+2014-10-15 Paolo Carlini <paolo.carlini@oracle.com>
+
+ * semantics.c (is_instantiation_of_constexpr, literal_type_p,
+ ensure_literal_type_for_constexpr_object,
+ constexpr_fundef_hasher::equal, constexpr_fundef_hasher::hash,
+ retrieve_constexpr_fundef, is_valid_constexpr_fn,
+ build_anon_member_initialization, build_data_member_initialization,
+ check_constexpr_bind_expr_vars, check_constexpr_ctor_body_1,
+ check_constexpr_ctor_body, sort_constexpr_mem_initializers,
+ build_constexpr_constructor_member_initializers, constexpr_fn_retval,
+ massage_constexpr_body, cx_check_missing_mem_inits,
+ register_constexpr_fundef, explain_invalid_constexpr_fn,
+ constexpr_call_hasher::hash, constexpr_call_hasher::equal,
+ maybe_initialize_constexpr_call_table, get_function_named_in_call,
+ get_nth_callarg, lookup_parameter_binding,
+ cxx_eval_builtin_function_call, adjust_temp_type,
+ cxx_bind_parameters_in_call, push_cx_call_context,
+ pop_cx_call_context, cx_error_context, cxx_eval_call_expression,
+ reduced_constant_expression_p, verify_constant,
+ cxx_eval_unary_expression, cxx_eval_binary_expression,
+ cxx_eval_conditional_expression, cxx_eval_array_reference,
+ cxx_eval_component_reference, cxx_eval_bit_field_ref,
+ cxx_eval_logical_expression, base_field_constructor_elt,
+ cxx_eval_bare_aggregate, cxx_eval_vec_init_1, cxx_eval_vec_init,
+ cxx_fold_indirect_ref, cxx_eval_indirect_ref, non_const_var_error,
+ cxx_eval_trinary_expression, var_in_constexpr_fn,
+ cxx_eval_constant_expression, cxx_eval_outermost_constant_expr,
+ is_sub_constant_expr, cxx_constant_value, maybe_constant_value,
+ maybe_constant_init, potential_constant_expression_1,
+ potential_constant_expression, potential_rvalue_constant_expression,
+ require_potential_constant_expression,
+ require_potential_rvalue_constant_expression): Moved definitions...
+ * constexpr.c: ... here, new file.
+ * Make-lang.in: Update.
+ * config-lang.in: Likewise.
+
2014-10-14 Jason Merrill <jason@redhat.com>
PR c++/63455
cp/mangle.o cp/cp-objcp-common.o cp/name-lookup.o cp/cxx-pretty-print.o \
cp/cp-cilkplus.o \
cp/cp-gimplify.o cp/cp-array-notation.o cp/lambda.o \
- cp/vtable-class-hierarchy.o $(CXX_C_OBJS)
+ cp/vtable-class-hierarchy.o cp/constexpr.o $(CXX_C_OBJS)
# Language-specific object files for C++.
CXX_OBJS = cp/cp-lang.o c-family/stub-objc.o $(CXX_AND_OBJCXX_OBJS)
target_libs="target-libstdc++-v3"
-gtfiles="\$(srcdir)/cp/rtti.c \$(srcdir)/cp/mangle.c \$(srcdir)/cp/name-lookup.h \$(srcdir)/cp/name-lookup.c \$(srcdir)/cp/cp-tree.h \$(srcdir)/cp/decl.h \$(srcdir)/cp/call.c \$(srcdir)/cp/decl.c \$(srcdir)/cp/decl2.c \$(srcdir)/cp/pt.c \$(srcdir)/cp/repo.c \$(srcdir)/cp/semantics.c \$(srcdir)/cp/tree.c \$(srcdir)/cp/parser.h \$(srcdir)/cp/parser.c \$(srcdir)/cp/method.c \$(srcdir)/cp/typeck2.c \$(srcdir)/c-family/c-common.c \$(srcdir)/c-family/c-common.h \$(srcdir)/c-family/c-objc.h \$(srcdir)/c-family/c-lex.c \$(srcdir)/c-family/c-pragma.h \$(srcdir)/c-family/c-pragma.c \$(srcdir)/cp/class.c \$(srcdir)/cp/cp-objcp-common.c \$(srcdir)/cp/cp-lang.c \$(srcdir)/cp/except.c \$(srcdir)/cp/vtable-class-hierarchy.c"
+gtfiles="\$(srcdir)/cp/rtti.c \$(srcdir)/cp/mangle.c \$(srcdir)/cp/name-lookup.h \$(srcdir)/cp/name-lookup.c \$(srcdir)/cp/cp-tree.h \$(srcdir)/cp/decl.h \$(srcdir)/cp/call.c \$(srcdir)/cp/decl.c \$(srcdir)/cp/decl2.c \$(srcdir)/cp/pt.c \$(srcdir)/cp/repo.c \$(srcdir)/cp/semantics.c \$(srcdir)/cp/tree.c \$(srcdir)/cp/parser.h \$(srcdir)/cp/parser.c \$(srcdir)/cp/method.c \$(srcdir)/cp/typeck2.c \$(srcdir)/c-family/c-common.c \$(srcdir)/c-family/c-common.h \$(srcdir)/c-family/c-objc.h \$(srcdir)/c-family/c-lex.c \$(srcdir)/c-family/c-pragma.h \$(srcdir)/c-family/c-pragma.c \$(srcdir)/cp/class.c \$(srcdir)/cp/cp-objcp-common.c \$(srcdir)/cp/cp-lang.c \$(srcdir)/cp/except.c \$(srcdir)/cp/vtable-class-hierarchy.c \$(srcdir)/cp/constexpr.c"
--- /dev/null
+/* Perform the semantic phase of constexpr parsing, i.e., the process of
+ building tree structure, checking semantic consistency, and
+ building RTL. These routines are used both during actual parsing
+ and during the instantiation of template functions.
+
+ Copyright (C) 1998-2014 Free Software Foundation, Inc.
+
+ This file is part of GCC.
+
+ GCC is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ GCC is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tree.h"
+#include "varasm.h"
+#include "cp-tree.h"
+#include "c-family/c-objc.h"
+#include "tree-iterator.h"
+#include "gimplify.h"
+#include "builtins.h"
+
+static bool verify_constant (tree, bool, bool *, bool *);
+#define VERIFY_CONSTANT(X) \
+do { \
+ if (verify_constant ((X), allow_non_constant, non_constant_p, overflow_p)) \
+ return t; \
+ } while (0)
+
+/* Returns true iff FUN is an instantiation of a constexpr function
+ template or a defaulted constexpr function. */
+
+bool
+is_instantiation_of_constexpr (tree fun)
+{
+ return ((DECL_TEMPLOID_INSTANTIATION (fun)
+ && DECL_DECLARED_CONSTEXPR_P (DECL_TI_TEMPLATE (fun)))
+ || (DECL_DEFAULTED_FN (fun)
+ && DECL_DECLARED_CONSTEXPR_P (fun)));
+}
+
+/* Return true if T is a literal type. */
+
+bool
+literal_type_p (tree t)
+{
+ if (SCALAR_TYPE_P (t)
+ || TREE_CODE (t) == VECTOR_TYPE
+ || TREE_CODE (t) == REFERENCE_TYPE)
+ return true;
+ if (CLASS_TYPE_P (t))
+ {
+ t = complete_type (t);
+ gcc_assert (COMPLETE_TYPE_P (t) || errorcount);
+ return CLASSTYPE_LITERAL_P (t);
+ }
+ if (TREE_CODE (t) == ARRAY_TYPE)
+ return literal_type_p (strip_array_types (t));
+ return false;
+}
+
+/* If DECL is a variable declared `constexpr', require its type
+ be literal. Return the DECL if OK, otherwise NULL. */
+
+tree
+ensure_literal_type_for_constexpr_object (tree decl)
+{
+ tree type = TREE_TYPE (decl);
+ if (VAR_P (decl)
+ && (DECL_DECLARED_CONSTEXPR_P (decl)
+ || var_in_constexpr_fn (decl))
+ && !processing_template_decl)
+ {
+ tree stype = strip_array_types (type);
+ if (CLASS_TYPE_P (stype) && !COMPLETE_TYPE_P (complete_type (stype)))
+ /* Don't complain here, we'll complain about incompleteness
+ when we try to initialize the variable. */;
+ else if (!literal_type_p (type))
+ {
+ if (DECL_DECLARED_CONSTEXPR_P (decl))
+ error ("the type %qT of constexpr variable %qD is not literal",
+ type, decl);
+ else
+ error ("variable %qD of non-literal type %qT in %<constexpr%> "
+ "function", decl, type);
+ explain_non_literal_class (type);
+ return NULL;
+ }
+ }
+ return decl;
+}
+
+/* Representation of entries in the constexpr function definition table. */
+
+struct GTY((for_user)) constexpr_fundef {
+ tree decl;
+ tree body;
+};
+
+struct constexpr_fundef_hasher : ggc_hasher<constexpr_fundef *>
+{
+ static hashval_t hash (constexpr_fundef *);
+ static bool equal (constexpr_fundef *, constexpr_fundef *);
+};
+
+/* This table holds all constexpr function definitions seen in
+ the current translation unit. */
+
+static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table;
+
+/* Utility function used for managing the constexpr function table.
+ Return true if the entries pointed to by P and Q are for the
+ same constexpr function. */
+
+inline bool
+constexpr_fundef_hasher::equal (constexpr_fundef *lhs, constexpr_fundef *rhs)
+{
+ return lhs->decl == rhs->decl;
+}
+
+/* Utility function used for managing the constexpr function table.
+ Return a hash value for the entry pointed to by Q. */
+
+inline hashval_t
+constexpr_fundef_hasher::hash (constexpr_fundef *fundef)
+{
+ return DECL_UID (fundef->decl);
+}
+
+/* Return a previously saved definition of function FUN. */
+
+static constexpr_fundef *
+retrieve_constexpr_fundef (tree fun)
+{
+ constexpr_fundef fundef = { NULL, NULL };
+ if (constexpr_fundef_table == NULL)
+ return NULL;
+
+ fundef.decl = fun;
+ return constexpr_fundef_table->find (&fundef);
+}
+
+/* Check whether the parameter and return types of FUN are valid for a
+ constexpr function, and complain if COMPLAIN. */
+
+static bool
+is_valid_constexpr_fn (tree fun, bool complain)
+{
+ bool ret = true;
+
+ if (DECL_INHERITED_CTOR_BASE (fun)
+ && TREE_CODE (fun) == TEMPLATE_DECL)
+ {
+ ret = false;
+ if (complain)
+ error ("inherited constructor %qD is not constexpr",
+ get_inherited_ctor (fun));
+ }
+ else
+ {
+ for (tree parm = FUNCTION_FIRST_USER_PARM (fun);
+ parm != NULL_TREE; parm = TREE_CHAIN (parm))
+ if (!literal_type_p (TREE_TYPE (parm)))
+ {
+ ret = false;
+ if (complain)
+ {
+ error ("invalid type for parameter %d of constexpr "
+ "function %q+#D", DECL_PARM_INDEX (parm), fun);
+ explain_non_literal_class (TREE_TYPE (parm));
+ }
+ }
+ }
+
+ if (!DECL_CONSTRUCTOR_P (fun))
+ {
+ tree rettype = TREE_TYPE (TREE_TYPE (fun));
+ if (!literal_type_p (rettype))
+ {
+ ret = false;
+ if (complain)
+ {
+ error ("invalid return type %qT of constexpr function %q+D",
+ rettype, fun);
+ explain_non_literal_class (rettype);
+ }
+ }
+
+ if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun)
+ && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun)))
+ {
+ ret = false;
+ if (complain)
+ {
+ error ("enclosing class of constexpr non-static member "
+ "function %q+#D is not a literal type", fun);
+ explain_non_literal_class (DECL_CONTEXT (fun));
+ }
+ }
+ }
+ else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun)))
+ {
+ ret = false;
+ if (complain)
+ error ("%q#T has virtual base classes", DECL_CONTEXT (fun));
+ }
+
+ return ret;
+}
+
+/* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF
+ for a member of an anonymous aggregate, INIT is the initializer for that
+ member, and VEC_OUTER is the vector of constructor elements for the class
+ whose constructor we are processing. Add the initializer to the vector
+ and return true to indicate success. */
+
+static bool
+build_anon_member_initialization (tree member, tree init,
+ vec<constructor_elt, va_gc> **vec_outer)
+{
+ /* MEMBER presents the relevant fields from the inside out, but we need
+ to build up the initializer from the outside in so that we can reuse
+ previously built CONSTRUCTORs if this is, say, the second field in an
+ anonymous struct. So we use a vec as a stack. */
+ auto_vec<tree, 2> fields;
+ do
+ {
+ fields.safe_push (TREE_OPERAND (member, 1));
+ member = TREE_OPERAND (member, 0);
+ }
+ while (ANON_AGGR_TYPE_P (TREE_TYPE (member))
+ && TREE_CODE (member) == COMPONENT_REF);
+
+ /* VEC has the constructor elements vector for the context of FIELD.
+ If FIELD is an anonymous aggregate, we will push inside it. */
+ vec<constructor_elt, va_gc> **vec = vec_outer;
+ tree field;
+ while (field = fields.pop(),
+ ANON_AGGR_TYPE_P (TREE_TYPE (field)))
+ {
+ tree ctor;
+ /* If there is already an outer constructor entry for the anonymous
+ aggregate FIELD, use it; otherwise, insert one. */
+ if (vec_safe_is_empty (*vec)
+ || (*vec)->last().index != field)
+ {
+ ctor = build_constructor (TREE_TYPE (field), NULL);
+ CONSTRUCTOR_APPEND_ELT (*vec, field, ctor);
+ }
+ else
+ ctor = (*vec)->last().value;
+ vec = &CONSTRUCTOR_ELTS (ctor);
+ }
+
+ /* Now we're at the innermost field, the one that isn't an anonymous
+ aggregate. Add its initializer to the CONSTRUCTOR and we're done. */
+ gcc_assert (fields.is_empty());
+ CONSTRUCTOR_APPEND_ELT (*vec, field, init);
+
+ return true;
+}
+
+/* Subroutine of build_constexpr_constructor_member_initializers.
+ The expression tree T represents a data member initialization
+ in a (constexpr) constructor definition. Build a pairing of
+ the data member with its initializer, and prepend that pair
+ to the existing initialization pair INITS. */
+
+static bool
+build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec)
+{
+ tree member, init;
+ if (TREE_CODE (t) == CLEANUP_POINT_EXPR)
+ t = TREE_OPERAND (t, 0);
+ if (TREE_CODE (t) == EXPR_STMT)
+ t = TREE_OPERAND (t, 0);
+ if (t == error_mark_node)
+ return false;
+ if (TREE_CODE (t) == STATEMENT_LIST)
+ {
+ tree_stmt_iterator i;
+ for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
+ {
+ if (! build_data_member_initialization (tsi_stmt (i), vec))
+ return false;
+ }
+ return true;
+ }
+ if (TREE_CODE (t) == CLEANUP_STMT)
+ {
+ /* We can't see a CLEANUP_STMT in a constructor for a literal class,
+ but we can in a constexpr constructor for a non-literal class. Just
+ ignore it; either all the initialization will be constant, in which
+ case the cleanup can't run, or it can't be constexpr.
+ Still recurse into CLEANUP_BODY. */
+ return build_data_member_initialization (CLEANUP_BODY (t), vec);
+ }
+ if (TREE_CODE (t) == CONVERT_EXPR)
+ t = TREE_OPERAND (t, 0);
+ if (TREE_CODE (t) == INIT_EXPR
+ || TREE_CODE (t) == MODIFY_EXPR)
+ {
+ member = TREE_OPERAND (t, 0);
+ init = break_out_target_exprs (TREE_OPERAND (t, 1));
+ }
+ else if (TREE_CODE (t) == CALL_EXPR)
+ {
+ member = CALL_EXPR_ARG (t, 0);
+ /* We don't use build_cplus_new here because it complains about
+ abstract bases. Leaving the call unwrapped means that it has the
+ wrong type, but cxx_eval_constant_expression doesn't care. */
+ init = break_out_target_exprs (t);
+ }
+ else if (TREE_CODE (t) == BIND_EXPR)
+ return build_data_member_initialization (BIND_EXPR_BODY (t), vec);
+ else if (TREE_CODE (t) == DECL_EXPR
+ || TREE_CODE (t) == USING_STMT)
+ /* Declaring a temporary, don't add it to the CONSTRUCTOR.
+ Likewise for using directives. */
+ return true;
+ else
+ gcc_unreachable ();
+ if (INDIRECT_REF_P (member))
+ member = TREE_OPERAND (member, 0);
+ if (TREE_CODE (member) == NOP_EXPR)
+ {
+ tree op = member;
+ STRIP_NOPS (op);
+ if (TREE_CODE (op) == ADDR_EXPR)
+ {
+ gcc_assert (same_type_ignoring_top_level_qualifiers_p
+ (TREE_TYPE (TREE_TYPE (op)),
+ TREE_TYPE (TREE_TYPE (member))));
+ /* Initializing a cv-qualified member; we need to look through
+ the const_cast. */
+ member = op;
+ }
+ else if (op == current_class_ptr
+ && (same_type_ignoring_top_level_qualifiers_p
+ (TREE_TYPE (TREE_TYPE (member)),
+ current_class_type)))
+ /* Delegating constructor. */
+ member = op;
+ else
+ {
+ /* This is an initializer for an empty base; keep it for now so
+ we can check it in cxx_eval_bare_aggregate. */
+ gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member))));
+ }
+ }
+ if (TREE_CODE (member) == ADDR_EXPR)
+ member = TREE_OPERAND (member, 0);
+ if (TREE_CODE (member) == COMPONENT_REF)
+ {
+ tree aggr = TREE_OPERAND (member, 0);
+ if (TREE_CODE (aggr) != COMPONENT_REF)
+ /* Normal member initialization. */
+ member = TREE_OPERAND (member, 1);
+ else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr)))
+ /* Initializing a member of an anonymous union. */
+ return build_anon_member_initialization (member, init, vec);
+ else
+ /* We're initializing a vtable pointer in a base. Leave it as
+ COMPONENT_REF so we remember the path to get to the vfield. */
+ gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node);
+ }
+
+ CONSTRUCTOR_APPEND_ELT (*vec, member, init);
+ return true;
+}
+
+/* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval.
+ In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a
+ BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */
+
+static bool
+check_constexpr_bind_expr_vars (tree t)
+{
+ gcc_assert (TREE_CODE (t) == BIND_EXPR);
+
+ if (cxx_dialect >= cxx14)
+ return true;
+
+ for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var))
+ if (TREE_CODE (var) == TYPE_DECL
+ && DECL_IMPLICIT_TYPEDEF_P (var))
+ return false;
+ return true;
+}
+
+/* Subroutine of check_constexpr_ctor_body. */
+
+static bool
+check_constexpr_ctor_body_1 (tree last, tree list)
+{
+ switch (TREE_CODE (list))
+ {
+ case DECL_EXPR:
+ if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL)
+ return true;
+ if (cxx_dialect >= cxx14)
+ return true;
+ return false;
+
+ case CLEANUP_POINT_EXPR:
+ return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0),
+ /*complain=*/false);
+
+ case BIND_EXPR:
+ if (!check_constexpr_bind_expr_vars (list)
+ || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list),
+ /*complain=*/false))
+ return false;
+ return true;
+
+ case USING_STMT:
+ case STATIC_ASSERT:
+ return true;
+
+ default:
+ return false;
+ }
+}
+
+/* Make sure that there are no statements after LAST in the constructor
+ body represented by LIST. */
+
+bool
+check_constexpr_ctor_body (tree last, tree list, bool complain)
+{
+ bool ok = true;
+ if (TREE_CODE (list) == STATEMENT_LIST)
+ {
+ tree_stmt_iterator i = tsi_last (list);
+ for (; !tsi_end_p (i); tsi_prev (&i))
+ {
+ tree t = tsi_stmt (i);
+ if (t == last)
+ break;
+ if (!check_constexpr_ctor_body_1 (last, t))
+ {
+ ok = false;
+ break;
+ }
+ }
+ }
+ else if (list != last
+ && !check_constexpr_ctor_body_1 (last, list))
+ ok = false;
+ if (!ok)
+ {
+ if (complain)
+ error ("constexpr constructor does not have empty body");
+ DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false;
+ }
+ return ok;
+}
+
+/* V is a vector of constructor elements built up for the base and member
+ initializers of a constructor for TYPE. They need to be in increasing
+ offset order, which they might not be yet if TYPE has a primary base
+ which is not first in the base-clause or a vptr and at least one base
+ all of which are non-primary. */
+
+static vec<constructor_elt, va_gc> *
+sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v)
+{
+ tree pri = CLASSTYPE_PRIMARY_BINFO (type);
+ tree field_type;
+ unsigned i;
+ constructor_elt *ce;
+
+ if (pri)
+ field_type = BINFO_TYPE (pri);
+ else if (TYPE_CONTAINS_VPTR_P (type))
+ field_type = vtbl_ptr_type_node;
+ else
+ return v;
+
+ /* Find the element for the primary base or vptr and move it to the
+ beginning of the vec. */
+ for (i = 0; vec_safe_iterate (v, i, &ce); ++i)
+ if (TREE_TYPE (ce->index) == field_type)
+ break;
+
+ if (i > 0 && i < vec_safe_length (v))
+ {
+ vec<constructor_elt, va_gc> &vref = *v;
+ constructor_elt elt = vref[i];
+ for (; i > 0; --i)
+ vref[i] = vref[i-1];
+ vref[0] = elt;
+ }
+
+ return v;
+}
+
+/* Build compile-time evalable representations of member-initializer list
+ for a constexpr constructor. */
+
+static tree
+build_constexpr_constructor_member_initializers (tree type, tree body)
+{
+ vec<constructor_elt, va_gc> *vec = NULL;
+ bool ok = true;
+ if (TREE_CODE (body) == MUST_NOT_THROW_EXPR
+ || TREE_CODE (body) == EH_SPEC_BLOCK)
+ body = TREE_OPERAND (body, 0);
+ if (TREE_CODE (body) == STATEMENT_LIST)
+ body = STATEMENT_LIST_HEAD (body)->stmt;
+ body = BIND_EXPR_BODY (body);
+ if (TREE_CODE (body) == CLEANUP_POINT_EXPR)
+ {
+ body = TREE_OPERAND (body, 0);
+ if (TREE_CODE (body) == EXPR_STMT)
+ body = TREE_OPERAND (body, 0);
+ if (TREE_CODE (body) == INIT_EXPR
+ && (same_type_ignoring_top_level_qualifiers_p
+ (TREE_TYPE (TREE_OPERAND (body, 0)),
+ current_class_type)))
+ {
+ /* Trivial copy. */
+ return TREE_OPERAND (body, 1);
+ }
+ ok = build_data_member_initialization (body, &vec);
+ }
+ else if (TREE_CODE (body) == STATEMENT_LIST)
+ {
+ tree_stmt_iterator i;
+ for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i))
+ {
+ ok = build_data_member_initialization (tsi_stmt (i), &vec);
+ if (!ok)
+ break;
+ }
+ }
+ else if (TREE_CODE (body) == TRY_BLOCK)
+ {
+ error ("body of %<constexpr%> constructor cannot be "
+ "a function-try-block");
+ return error_mark_node;
+ }
+ else if (EXPR_P (body))
+ ok = build_data_member_initialization (body, &vec);
+ else
+ gcc_assert (errorcount > 0);
+ if (ok)
+ {
+ if (vec_safe_length (vec) > 0)
+ {
+ /* In a delegating constructor, return the target. */
+ constructor_elt *ce = &(*vec)[0];
+ if (ce->index == current_class_ptr)
+ {
+ body = ce->value;
+ vec_free (vec);
+ return body;
+ }
+ }
+ vec = sort_constexpr_mem_initializers (type, vec);
+ return build_constructor (type, vec);
+ }
+ else
+ return error_mark_node;
+}
+
+/* Subroutine of register_constexpr_fundef. BODY is the body of a function
+ declared to be constexpr, or a sub-statement thereof. Returns the
+ return value if suitable, error_mark_node for a statement not allowed in
+ a constexpr function, or NULL_TREE if no return value was found. */
+
+static tree
+constexpr_fn_retval (tree body)
+{
+ switch (TREE_CODE (body))
+ {
+ case STATEMENT_LIST:
+ {
+ tree_stmt_iterator i;
+ tree expr = NULL_TREE;
+ for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i))
+ {
+ tree s = constexpr_fn_retval (tsi_stmt (i));
+ if (s == error_mark_node)
+ return error_mark_node;
+ else if (s == NULL_TREE)
+ /* Keep iterating. */;
+ else if (expr)
+ /* Multiple return statements. */
+ return error_mark_node;
+ else
+ expr = s;
+ }
+ return expr;
+ }
+
+ case RETURN_EXPR:
+ return break_out_target_exprs (TREE_OPERAND (body, 0));
+
+ case DECL_EXPR:
+ if (TREE_CODE (DECL_EXPR_DECL (body)) == USING_DECL)
+ return NULL_TREE;
+ if (cxx_dialect >= cxx14)
+ return NULL_TREE;
+ return error_mark_node;
+
+ case CLEANUP_POINT_EXPR:
+ return constexpr_fn_retval (TREE_OPERAND (body, 0));
+
+ case BIND_EXPR:
+ if (!check_constexpr_bind_expr_vars (body))
+ return error_mark_node;
+ return constexpr_fn_retval (BIND_EXPR_BODY (body));
+
+ case USING_STMT:
+ return NULL_TREE;
+
+ default:
+ return error_mark_node;
+ }
+}
+
+/* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of
+ FUN; do the necessary transformations to turn it into a single expression
+ that we can store in the hash table. */
+
+static tree
+massage_constexpr_body (tree fun, tree body)
+{
+ if (DECL_CONSTRUCTOR_P (fun))
+ body = build_constexpr_constructor_member_initializers
+ (DECL_CONTEXT (fun), body);
+ else
+ {
+ if (TREE_CODE (body) == EH_SPEC_BLOCK)
+ body = EH_SPEC_STMTS (body);
+ if (TREE_CODE (body) == MUST_NOT_THROW_EXPR)
+ body = TREE_OPERAND (body, 0);
+ body = constexpr_fn_retval (body);
+ }
+ return body;
+}
+
+/* FUN is a constexpr constructor with massaged body BODY. Return true
+ if some bases/fields are uninitialized, and complain if COMPLAIN. */
+
+static bool
+cx_check_missing_mem_inits (tree fun, tree body, bool complain)
+{
+ bool bad;
+ tree field;
+ unsigned i, nelts;
+ tree ctype;
+
+ if (TREE_CODE (body) != CONSTRUCTOR)
+ return false;
+
+ nelts = CONSTRUCTOR_NELTS (body);
+ ctype = DECL_CONTEXT (fun);
+ field = TYPE_FIELDS (ctype);
+
+ if (TREE_CODE (ctype) == UNION_TYPE)
+ {
+ if (nelts == 0 && next_initializable_field (field))
+ {
+ if (complain)
+ error ("%<constexpr%> constructor for union %qT must "
+ "initialize exactly one non-static data member", ctype);
+ return true;
+ }
+ return false;
+ }
+
+ bad = false;
+ for (i = 0; i <= nelts; ++i)
+ {
+ tree index;
+ if (i == nelts)
+ index = NULL_TREE;
+ else
+ {
+ index = CONSTRUCTOR_ELT (body, i)->index;
+ /* Skip base and vtable inits. */
+ if (TREE_CODE (index) != FIELD_DECL
+ || DECL_ARTIFICIAL (index))
+ continue;
+ }
+ for (; field != index; field = DECL_CHAIN (field))
+ {
+ tree ftype;
+ if (TREE_CODE (field) != FIELD_DECL
+ || (DECL_C_BIT_FIELD (field) && !DECL_NAME (field))
+ || DECL_ARTIFICIAL (field))
+ continue;
+ ftype = strip_array_types (TREE_TYPE (field));
+ if (type_has_constexpr_default_constructor (ftype))
+ {
+ /* It's OK to skip a member with a trivial constexpr ctor.
+ A constexpr ctor that isn't trivial should have been
+ added in by now. */
+ gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype)
+ || errorcount != 0);
+ continue;
+ }
+ if (!complain)
+ return true;
+ error ("uninitialized member %qD in %<constexpr%> constructor",
+ field);
+ bad = true;
+ }
+ if (field == NULL_TREE)
+ break;
+ field = DECL_CHAIN (field);
+ }
+
+ return bad;
+}
+
+/* We are processing the definition of the constexpr function FUN.
+ Check that its BODY fulfills the propriate requirements and
+ enter it in the constexpr function definition table.
+ For constructor BODY is actually the TREE_LIST of the
+ member-initializer list. */
+
+tree
+register_constexpr_fundef (tree fun, tree body)
+{
+ constexpr_fundef entry;
+ constexpr_fundef **slot;
+
+ if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun)))
+ return NULL;
+
+ body = massage_constexpr_body (fun, body);
+ if (body == NULL_TREE || body == error_mark_node)
+ {
+ if (!DECL_CONSTRUCTOR_P (fun))
+ error ("body of constexpr function %qD not a return-statement", fun);
+ return NULL;
+ }
+
+ if (!potential_rvalue_constant_expression (body))
+ {
+ if (!DECL_GENERATED_P (fun))
+ require_potential_rvalue_constant_expression (body);
+ return NULL;
+ }
+
+ if (DECL_CONSTRUCTOR_P (fun)
+ && cx_check_missing_mem_inits (fun, body, !DECL_GENERATED_P (fun)))
+ return NULL;
+
+ /* Create the constexpr function table if necessary. */
+ if (constexpr_fundef_table == NULL)
+ constexpr_fundef_table
+ = hash_table<constexpr_fundef_hasher>::create_ggc (101);
+
+ entry.decl = fun;
+ entry.body = body;
+ slot = constexpr_fundef_table->find_slot (&entry, INSERT);
+
+ gcc_assert (*slot == NULL);
+ *slot = ggc_alloc<constexpr_fundef> ();
+ **slot = entry;
+
+ return fun;
+}
+
+/* FUN is a non-constexpr function called in a context that requires a
+ constant expression. If it comes from a constexpr template, explain why
+ the instantiation isn't constexpr. */
+
+void
+explain_invalid_constexpr_fn (tree fun)
+{
+ static hash_set<tree> *diagnosed;
+ tree body;
+ location_t save_loc;
+ /* Only diagnose defaulted functions or instantiations. */
+ if (!DECL_DEFAULTED_FN (fun)
+ && !is_instantiation_of_constexpr (fun))
+ return;
+ if (diagnosed == NULL)
+ diagnosed = new hash_set<tree>;
+ if (diagnosed->add (fun))
+ /* Already explained. */
+ return;
+
+ save_loc = input_location;
+ input_location = DECL_SOURCE_LOCATION (fun);
+ inform (0, "%q+D is not usable as a constexpr function because:", fun);
+ /* First check the declaration. */
+ if (is_valid_constexpr_fn (fun, true))
+ {
+ /* Then if it's OK, the body. */
+ if (!DECL_DECLARED_CONSTEXPR_P (fun))
+ explain_implicit_non_constexpr (fun);
+ else
+ {
+ body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun));
+ require_potential_rvalue_constant_expression (body);
+ if (DECL_CONSTRUCTOR_P (fun))
+ cx_check_missing_mem_inits (fun, body, true);
+ }
+ }
+ input_location = save_loc;
+}
+
+/* Objects of this type represent calls to constexpr functions
+ along with the bindings of parameters to their arguments, for
+ the purpose of compile time evaluation. */
+
+struct GTY((for_user)) constexpr_call {
+ /* Description of the constexpr function definition. */
+ constexpr_fundef *fundef;
+ /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE
+ is a parameter _DECL and the TREE_VALUE is the value of the parameter.
+ Note: This arrangement is made to accommodate the use of
+ iterative_hash_template_arg (see pt.c). If you change this
+ representation, also change the hash calculation in
+ cxx_eval_call_expression. */
+ tree bindings;
+ /* Result of the call.
+ NULL means the call is being evaluated.
+ error_mark_node means that the evaluation was erroneous;
+ otherwise, the actuall value of the call. */
+ tree result;
+ /* The hash of this call; we remember it here to avoid having to
+ recalculate it when expanding the hash table. */
+ hashval_t hash;
+};
+
+struct constexpr_call_hasher : ggc_hasher<constexpr_call *>
+{
+ static hashval_t hash (constexpr_call *);
+ static bool equal (constexpr_call *, constexpr_call *);
+ };
+
+/* A table of all constexpr calls that have been evaluated by the
+ compiler in this translation unit. */
+
+static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table;
+
+static tree cxx_eval_constant_expression (const constexpr_call *, tree,
+ bool, bool, bool *, bool *);
+
+/* Compute a hash value for a constexpr call representation. */
+
+inline hashval_t
+constexpr_call_hasher::hash (constexpr_call *info)
+{
+ return info->hash;
+}
+
+/* Return true if the objects pointed to by P and Q represent calls
+ to the same constexpr function with the same arguments.
+ Otherwise, return false. */
+
+bool
+constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs)
+{
+ tree lhs_bindings;
+ tree rhs_bindings;
+ if (lhs == rhs)
+ return 1;
+ if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef))
+ return 0;
+ lhs_bindings = lhs->bindings;
+ rhs_bindings = rhs->bindings;
+ while (lhs_bindings != NULL && rhs_bindings != NULL)
+ {
+ tree lhs_arg = TREE_VALUE (lhs_bindings);
+ tree rhs_arg = TREE_VALUE (rhs_bindings);
+ gcc_assert (TREE_TYPE (lhs_arg) == TREE_TYPE (rhs_arg));
+ if (!cp_tree_equal (lhs_arg, rhs_arg))
+ return 0;
+ lhs_bindings = TREE_CHAIN (lhs_bindings);
+ rhs_bindings = TREE_CHAIN (rhs_bindings);
+ }
+ return lhs_bindings == rhs_bindings;
+}
+
+/* Initialize the constexpr call table, if needed. */
+
+static void
+maybe_initialize_constexpr_call_table (void)
+{
+ if (constexpr_call_table == NULL)
+ constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101);
+}
+
+/* We have an expression tree T that represents a call, either CALL_EXPR
+ or AGGR_INIT_EXPR. If the call is lexically to a named function,
+ retrun the _DECL for that function. */
+
+static tree
+get_function_named_in_call (tree t)
+{
+ tree fun = NULL;
+ switch (TREE_CODE (t))
+ {
+ case CALL_EXPR:
+ fun = CALL_EXPR_FN (t);
+ break;
+
+ case AGGR_INIT_EXPR:
+ fun = AGGR_INIT_EXPR_FN (t);
+ break;
+
+ default:
+ gcc_unreachable();
+ break;
+ }
+ if (TREE_CODE (fun) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL)
+ fun = TREE_OPERAND (fun, 0);
+ return fun;
+}
+
+/* We have an expression tree T that represents a call, either CALL_EXPR
+ or AGGR_INIT_EXPR. Return the Nth argument. */
+
+static inline tree
+get_nth_callarg (tree t, int n)
+{
+ switch (TREE_CODE (t))
+ {
+ case CALL_EXPR:
+ return CALL_EXPR_ARG (t, n);
+
+ case AGGR_INIT_EXPR:
+ return AGGR_INIT_EXPR_ARG (t, n);
+
+ default:
+ gcc_unreachable ();
+ return NULL;
+ }
+}
+
+/* Look up the binding of the function parameter T in a constexpr
+ function call context CALL. */
+
+static tree
+lookup_parameter_binding (const constexpr_call *call, tree t)
+{
+ tree b = purpose_member (t, call->bindings);
+ return TREE_VALUE (b);
+}
+
+/* Attempt to evaluate T which represents a call to a builtin function.
+ We assume here that all builtin functions evaluate to scalar types
+ represented by _CST nodes. */
+
+static tree
+cxx_eval_builtin_function_call (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ const int nargs = call_expr_nargs (t);
+ tree *args = (tree *) alloca (nargs * sizeof (tree));
+ tree new_call;
+ int i;
+ for (i = 0; i < nargs; ++i)
+ {
+ args[i] = cxx_eval_constant_expression (call, CALL_EXPR_ARG (t, i),
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ if (allow_non_constant && *non_constant_p)
+ return t;
+ }
+ if (*non_constant_p)
+ return t;
+ new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t),
+ CALL_EXPR_FN (t), nargs, args);
+ new_call = fold (new_call);
+ VERIFY_CONSTANT (new_call);
+ return new_call;
+}
+
+/* TEMP is the constant value of a temporary object of type TYPE. Adjust
+ the type of the value to match. */
+
+static tree
+adjust_temp_type (tree type, tree temp)
+{
+ if (TREE_TYPE (temp) == type)
+ return temp;
+ /* Avoid wrapping an aggregate value in a NOP_EXPR. */
+ if (TREE_CODE (temp) == CONSTRUCTOR)
+ return build_constructor (type, CONSTRUCTOR_ELTS (temp));
+ gcc_assert (scalarish_type_p (type));
+ return cp_fold_convert (type, temp);
+}
+
+/* Subroutine of cxx_eval_call_expression.
+ We are processing a call expression (either CALL_EXPR or
+ AGGR_INIT_EXPR) in the call context of OLD_CALL. Evaluate
+ all arguments and bind their values to correspondings
+ parameters, making up the NEW_CALL context. */
+
+static void
+cxx_bind_parameters_in_call (const constexpr_call *old_call, tree t,
+ constexpr_call *new_call,
+ bool allow_non_constant,
+ bool *non_constant_p, bool *overflow_p)
+{
+ const int nargs = call_expr_nargs (t);
+ tree fun = new_call->fundef->decl;
+ tree parms = DECL_ARGUMENTS (fun);
+ int i;
+ for (i = 0; i < nargs; ++i)
+ {
+ tree x, arg;
+ tree type = parms ? TREE_TYPE (parms) : void_type_node;
+ /* For member function, the first argument is a pointer to the implied
+ object. And for an object construction, don't bind `this' before
+ it is fully constructed. */
+ if (i == 0 && DECL_CONSTRUCTOR_P (fun))
+ goto next;
+ x = get_nth_callarg (t, i);
+ if (parms && DECL_BY_REFERENCE (parms))
+ {
+ /* cp_genericize made this a reference for argument passing, but
+ we don't want to treat it like one for constexpr evaluation. */
+ gcc_assert (TREE_CODE (type) == REFERENCE_TYPE);
+ gcc_assert (TREE_CODE (TREE_TYPE (x)) == REFERENCE_TYPE);
+ type = TREE_TYPE (type);
+ x = convert_from_reference (x);
+ }
+ arg = cxx_eval_constant_expression (old_call, x, allow_non_constant,
+ TREE_CODE (type) == REFERENCE_TYPE,
+ non_constant_p, overflow_p);
+ /* Don't VERIFY_CONSTANT here. */
+ if (*non_constant_p && allow_non_constant)
+ return;
+ /* Just discard ellipsis args after checking their constantitude. */
+ if (!parms)
+ continue;
+ if (*non_constant_p)
+ /* Don't try to adjust the type of non-constant args. */
+ goto next;
+
+ /* Make sure the binding has the same type as the parm. */
+ if (TREE_CODE (type) != REFERENCE_TYPE)
+ arg = adjust_temp_type (type, arg);
+ new_call->bindings = tree_cons (parms, arg, new_call->bindings);
+ next:
+ parms = TREE_CHAIN (parms);
+ }
+}
+
+/* Variables and functions to manage constexpr call expansion context.
+ These do not need to be marked for PCH or GC. */
+
+/* FIXME remember and print actual constant arguments. */
+static vec<tree> call_stack = vNULL;
+static int call_stack_tick;
+static int last_cx_error_tick;
+
+static bool
+push_cx_call_context (tree call)
+{
+ ++call_stack_tick;
+ if (!EXPR_HAS_LOCATION (call))
+ SET_EXPR_LOCATION (call, input_location);
+ call_stack.safe_push (call);
+ if (call_stack.length () > (unsigned) max_constexpr_depth)
+ return false;
+ return true;
+}
+
+static void
+pop_cx_call_context (void)
+{
+ ++call_stack_tick;
+ call_stack.pop ();
+}
+
+vec<tree>
+cx_error_context (void)
+{
+ vec<tree> r = vNULL;
+ if (call_stack_tick != last_cx_error_tick
+ && !call_stack.is_empty ())
+ r = call_stack;
+ last_cx_error_tick = call_stack_tick;
+ return r;
+}
+
+/* Subroutine of cxx_eval_constant_expression.
+ Evaluate the call expression tree T in the context of OLD_CALL expression
+ evaluation. */
+
+static tree
+cxx_eval_call_expression (const constexpr_call *old_call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ location_t loc = EXPR_LOC_OR_LOC (t, input_location);
+ tree fun = get_function_named_in_call (t);
+ tree result;
+ constexpr_call new_call = { NULL, NULL, NULL, 0 };
+ constexpr_call **slot;
+ constexpr_call *entry;
+ bool depth_ok;
+
+ if (TREE_CODE (fun) != FUNCTION_DECL)
+ {
+ /* Might be a constexpr function pointer. */
+ fun = cxx_eval_constant_expression (old_call, fun, allow_non_constant,
+ /*addr*/false, non_constant_p,
+ overflow_p);
+ STRIP_NOPS (fun);
+ if (TREE_CODE (fun) == ADDR_EXPR)
+ fun = TREE_OPERAND (fun, 0);
+ }
+ if (TREE_CODE (fun) != FUNCTION_DECL)
+ {
+ if (!allow_non_constant && !*non_constant_p)
+ error_at (loc, "expression %qE does not designate a constexpr "
+ "function", fun);
+ *non_constant_p = true;
+ return t;
+ }
+ if (DECL_CLONED_FUNCTION_P (fun))
+ fun = DECL_CLONED_FUNCTION (fun);
+ if (is_builtin_fn (fun))
+ return cxx_eval_builtin_function_call (old_call, t, allow_non_constant,
+ addr, non_constant_p, overflow_p);
+ if (!DECL_DECLARED_CONSTEXPR_P (fun))
+ {
+ if (!allow_non_constant)
+ {
+ error_at (loc, "call to non-constexpr function %qD", fun);
+ explain_invalid_constexpr_fn (fun);
+ }
+ *non_constant_p = true;
+ return t;
+ }
+
+ /* Shortcut trivial constructor/op=. */
+ if (trivial_fn_p (fun))
+ {
+ if (call_expr_nargs (t) == 2)
+ {
+ tree arg = convert_from_reference (get_nth_callarg (t, 1));
+ return cxx_eval_constant_expression (old_call, arg, allow_non_constant,
+ addr, non_constant_p, overflow_p);
+ }
+ else if (TREE_CODE (t) == AGGR_INIT_EXPR
+ && AGGR_INIT_ZERO_FIRST (t))
+ return build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false);
+ }
+
+ /* If in direct recursive call, optimize definition search. */
+ if (old_call != NULL && old_call->fundef->decl == fun)
+ new_call.fundef = old_call->fundef;
+ else
+ {
+ new_call.fundef = retrieve_constexpr_fundef (fun);
+ if (new_call.fundef == NULL || new_call.fundef->body == NULL)
+ {
+ if (!allow_non_constant)
+ {
+ if (DECL_INITIAL (fun))
+ {
+ /* The definition of fun was somehow unsuitable. */
+ error_at (loc, "%qD called in a constant expression", fun);
+ explain_invalid_constexpr_fn (fun);
+ }
+ else
+ error_at (loc, "%qD used before its definition", fun);
+ }
+ *non_constant_p = true;
+ return t;
+ }
+ }
+ cxx_bind_parameters_in_call (old_call, t, &new_call,
+ allow_non_constant, non_constant_p, overflow_p);
+ if (*non_constant_p)
+ return t;
+
+ depth_ok = push_cx_call_context (t);
+
+ new_call.hash
+ = iterative_hash_template_arg (new_call.bindings,
+ constexpr_fundef_hasher::hash (new_call.fundef));
+
+ /* If we have seen this call before, we are done. */
+ maybe_initialize_constexpr_call_table ();
+ slot = constexpr_call_table->find_slot (&new_call, INSERT);
+ entry = *slot;
+ if (entry == NULL)
+ {
+ /* We need to keep a pointer to the entry, not just the slot, as the
+ slot can move in the call to cxx_eval_builtin_function_call. */
+ *slot = entry = ggc_alloc<constexpr_call> ();
+ *entry = new_call;
+ }
+ /* Calls which are in progress have their result set to NULL
+ so that we can detect circular dependencies. */
+ else if (entry->result == NULL)
+ {
+ if (!allow_non_constant)
+ error ("call has circular dependency");
+ *non_constant_p = true;
+ entry->result = result = error_mark_node;
+ }
+
+ if (!depth_ok)
+ {
+ if (!allow_non_constant)
+ error ("constexpr evaluation depth exceeds maximum of %d (use "
+ "-fconstexpr-depth= to increase the maximum)",
+ max_constexpr_depth);
+ *non_constant_p = true;
+ entry->result = result = error_mark_node;
+ }
+ else
+ {
+ result = entry->result;
+ if (!result || result == error_mark_node)
+ result = (cxx_eval_constant_expression
+ (&new_call, new_call.fundef->body,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p));
+ if (result == error_mark_node)
+ *non_constant_p = true;
+ if (*non_constant_p)
+ entry->result = result = error_mark_node;
+ else
+ {
+ /* If this was a call to initialize an object, set the type of
+ the CONSTRUCTOR to the type of that object. */
+ if (DECL_CONSTRUCTOR_P (fun))
+ {
+ tree ob_arg = get_nth_callarg (t, 0);
+ STRIP_NOPS (ob_arg);
+ gcc_assert (TYPE_PTR_P (TREE_TYPE (ob_arg))
+ && CLASS_TYPE_P (TREE_TYPE (TREE_TYPE (ob_arg))));
+ result = adjust_temp_type (TREE_TYPE (TREE_TYPE (ob_arg)),
+ result);
+ }
+ entry->result = result;
+ }
+ }
+
+ pop_cx_call_context ();
+ return unshare_expr (result);
+}
+
+/* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */
+
+bool
+reduced_constant_expression_p (tree t)
+{
+ switch (TREE_CODE (t))
+ {
+ case PTRMEM_CST:
+ /* Even if we can't lower this yet, it's constant. */
+ return true;
+
+ case CONSTRUCTOR:
+ /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */
+ tree elt; unsigned HOST_WIDE_INT idx;
+ FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), idx, elt)
+ if (!reduced_constant_expression_p (elt))
+ return false;
+ return true;
+
+ default:
+ /* FIXME are we calling this too much? */
+ return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE;
+ }
+}
+
+/* Some expressions may have constant operands but are not constant
+ themselves, such as 1/0. Call this function (or rather, the macro
+ following it) to check for that condition.
+
+ We only call this in places that require an arithmetic constant, not in
+ places where we might have a non-constant expression that can be a
+ component of a constant expression, such as the address of a constexpr
+ variable that might be dereferenced later. */
+
+static bool
+verify_constant (tree t, bool allow_non_constant, bool *non_constant_p,
+ bool *overflow_p)
+{
+ if (!*non_constant_p && !reduced_constant_expression_p (t))
+ {
+ if (!allow_non_constant)
+ error ("%q+E is not a constant expression", t);
+ *non_constant_p = true;
+ }
+ if (TREE_OVERFLOW_P (t))
+ {
+ if (!allow_non_constant)
+ {
+ permerror (input_location, "overflow in constant expression");
+ /* If we're being permissive (and are in an enforcing
+ context), ignore the overflow. */
+ if (flag_permissive)
+ return *non_constant_p;
+ }
+ *overflow_p = true;
+ }
+ return *non_constant_p;
+}
+
+/* Subroutine of cxx_eval_constant_expression.
+ Attempt to reduce the unary expression tree T to a compile time value.
+ If successful, return the value. Otherwise issue a diagnostic
+ and return error_mark_node. */
+
+static tree
+cxx_eval_unary_expression (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ tree r;
+ tree orig_arg = TREE_OPERAND (t, 0);
+ tree arg = cxx_eval_constant_expression (call, orig_arg, allow_non_constant,
+ addr, non_constant_p, overflow_p);
+ VERIFY_CONSTANT (arg);
+ if (arg == orig_arg)
+ return t;
+ r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), arg);
+ VERIFY_CONSTANT (r);
+ return r;
+}
+
+/* Subroutine of cxx_eval_constant_expression.
+ Like cxx_eval_unary_expression, except for binary expressions. */
+
+static tree
+cxx_eval_binary_expression (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ tree r;
+ tree orig_lhs = TREE_OPERAND (t, 0);
+ tree orig_rhs = TREE_OPERAND (t, 1);
+ tree lhs, rhs;
+ lhs = cxx_eval_constant_expression (call, orig_lhs,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ VERIFY_CONSTANT (lhs);
+ rhs = cxx_eval_constant_expression (call, orig_rhs,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ VERIFY_CONSTANT (rhs);
+ if (lhs == orig_lhs && rhs == orig_rhs)
+ return t;
+ r = fold_build2 (TREE_CODE (t), TREE_TYPE (t), lhs, rhs);
+ VERIFY_CONSTANT (r);
+ return r;
+}
+
+/* Subroutine of cxx_eval_constant_expression.
+ Attempt to evaluate condition expressions. Dead branches are not
+ looked into. */
+
+static tree
+cxx_eval_conditional_expression (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ tree val = cxx_eval_constant_expression (call, TREE_OPERAND (t, 0),
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ VERIFY_CONSTANT (val);
+ /* Don't VERIFY_CONSTANT the other operands. */
+ if (integer_zerop (val))
+ return cxx_eval_constant_expression (call, TREE_OPERAND (t, 2),
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ return cxx_eval_constant_expression (call, TREE_OPERAND (t, 1),
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+}
+
+/* Subroutine of cxx_eval_constant_expression.
+ Attempt to reduce a reference to an array slot. */
+
+static tree
+cxx_eval_array_reference (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ tree oldary = TREE_OPERAND (t, 0);
+ tree ary = cxx_eval_constant_expression (call, oldary,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ tree index, oldidx;
+ HOST_WIDE_INT i;
+ tree elem_type;
+ unsigned len, elem_nchars = 1;
+ if (*non_constant_p)
+ return t;
+ oldidx = TREE_OPERAND (t, 1);
+ index = cxx_eval_constant_expression (call, oldidx,
+ allow_non_constant, false,
+ non_constant_p, overflow_p);
+ VERIFY_CONSTANT (index);
+ if (addr && ary == oldary && index == oldidx)
+ return t;
+ else if (addr)
+ return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL);
+ elem_type = TREE_TYPE (TREE_TYPE (ary));
+ if (TREE_CODE (ary) == CONSTRUCTOR)
+ len = CONSTRUCTOR_NELTS (ary);
+ else if (TREE_CODE (ary) == STRING_CST)
+ {
+ elem_nchars = (TYPE_PRECISION (elem_type)
+ / TYPE_PRECISION (char_type_node));
+ len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars;
+ }
+ else
+ {
+ /* We can't do anything with other tree codes, so use
+ VERIFY_CONSTANT to complain and fail. */
+ VERIFY_CONSTANT (ary);
+ gcc_unreachable ();
+ }
+ if (compare_tree_int (index, len) >= 0)
+ {
+ if (tree_int_cst_lt (index, array_type_nelts_top (TREE_TYPE (ary))))
+ {
+ /* If it's within the array bounds but doesn't have an explicit
+ initializer, it's value-initialized. */
+ tree val = build_value_init (elem_type, tf_warning_or_error);
+ return cxx_eval_constant_expression (call, val,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ }
+
+ if (!allow_non_constant)
+ error ("array subscript out of bound");
+ *non_constant_p = true;
+ return t;
+ }
+ else if (tree_int_cst_lt (index, integer_zero_node))
+ {
+ if (!allow_non_constant)
+ error ("negative array subscript");
+ *non_constant_p = true;
+ return t;
+ }
+ i = tree_to_shwi (index);
+ if (TREE_CODE (ary) == CONSTRUCTOR)
+ return (*CONSTRUCTOR_ELTS (ary))[i].value;
+ else if (elem_nchars == 1)
+ return build_int_cst (cv_unqualified (TREE_TYPE (TREE_TYPE (ary))),
+ TREE_STRING_POINTER (ary)[i]);
+ else
+ {
+ tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (ary)));
+ return native_interpret_expr (type, (const unsigned char *)
+ TREE_STRING_POINTER (ary)
+ + i * elem_nchars, elem_nchars);
+ }
+ /* Don't VERIFY_CONSTANT here. */
+}
+
+/* Subroutine of cxx_eval_constant_expression.
+ Attempt to reduce a field access of a value of class type. */
+
+static tree
+cxx_eval_component_reference (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ unsigned HOST_WIDE_INT i;
+ tree field;
+ tree value;
+ tree part = TREE_OPERAND (t, 1);
+ tree orig_whole = TREE_OPERAND (t, 0);
+ tree whole = cxx_eval_constant_expression (call, orig_whole,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ if (whole == orig_whole)
+ return t;
+ if (addr)
+ return fold_build3 (COMPONENT_REF, TREE_TYPE (t),
+ whole, part, NULL_TREE);
+ /* Don't VERIFY_CONSTANT here; we only want to check that we got a
+ CONSTRUCTOR. */
+ if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR)
+ {
+ if (!allow_non_constant)
+ error ("%qE is not a constant expression", orig_whole);
+ *non_constant_p = true;
+ }
+ if (DECL_MUTABLE_P (part))
+ {
+ if (!allow_non_constant)
+ error ("mutable %qD is not usable in a constant expression", part);
+ *non_constant_p = true;
+ }
+ if (*non_constant_p)
+ return t;
+ FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value)
+ {
+ if (field == part)
+ return value;
+ }
+ if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE
+ && CONSTRUCTOR_NELTS (whole) > 0)
+ {
+ /* DR 1188 says we don't have to deal with this. */
+ if (!allow_non_constant)
+ error ("accessing %qD member instead of initialized %qD member in "
+ "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index);
+ *non_constant_p = true;
+ return t;
+ }
+
+ /* If there's no explicit init for this field, it's value-initialized. */
+ value = build_value_init (TREE_TYPE (t), tf_warning_or_error);
+ return cxx_eval_constant_expression (call, value,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+}
+
+/* Subroutine of cxx_eval_constant_expression.
+ Attempt to reduce a field access of a value of class type that is
+ expressed as a BIT_FIELD_REF. */
+
+static tree
+cxx_eval_bit_field_ref (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ tree orig_whole = TREE_OPERAND (t, 0);
+ tree retval, fldval, utype, mask;
+ bool fld_seen = false;
+ HOST_WIDE_INT istart, isize;
+ tree whole = cxx_eval_constant_expression (call, orig_whole,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ tree start, field, value;
+ unsigned HOST_WIDE_INT i;
+
+ if (whole == orig_whole)
+ return t;
+ /* Don't VERIFY_CONSTANT here; we only want to check that we got a
+ CONSTRUCTOR. */
+ if (!*non_constant_p
+ && TREE_CODE (whole) != VECTOR_CST
+ && TREE_CODE (whole) != CONSTRUCTOR)
+ {
+ if (!allow_non_constant)
+ error ("%qE is not a constant expression", orig_whole);
+ *non_constant_p = true;
+ }
+ if (*non_constant_p)
+ return t;
+
+ if (TREE_CODE (whole) == VECTOR_CST)
+ return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole,
+ TREE_OPERAND (t, 1), TREE_OPERAND (t, 2));
+
+ start = TREE_OPERAND (t, 2);
+ istart = tree_to_shwi (start);
+ isize = tree_to_shwi (TREE_OPERAND (t, 1));
+ utype = TREE_TYPE (t);
+ if (!TYPE_UNSIGNED (utype))
+ utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1);
+ retval = build_int_cst (utype, 0);
+ FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value)
+ {
+ tree bitpos = bit_position (field);
+ if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1))
+ return value;
+ if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE
+ && TREE_CODE (value) == INTEGER_CST
+ && tree_fits_shwi_p (bitpos)
+ && tree_fits_shwi_p (DECL_SIZE (field)))
+ {
+ HOST_WIDE_INT bit = tree_to_shwi (bitpos);
+ HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field));
+ HOST_WIDE_INT shift;
+ if (bit >= istart && bit + sz <= istart + isize)
+ {
+ fldval = fold_convert (utype, value);
+ mask = build_int_cst_type (utype, -1);
+ mask = fold_build2 (LSHIFT_EXPR, utype, mask,
+ size_int (TYPE_PRECISION (utype) - sz));
+ mask = fold_build2 (RSHIFT_EXPR, utype, mask,
+ size_int (TYPE_PRECISION (utype) - sz));
+ fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask);
+ shift = bit - istart;
+ if (BYTES_BIG_ENDIAN)
+ shift = TYPE_PRECISION (utype) - shift - sz;
+ fldval = fold_build2 (LSHIFT_EXPR, utype, fldval,
+ size_int (shift));
+ retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval);
+ fld_seen = true;
+ }
+ }
+ }
+ if (fld_seen)
+ return fold_convert (TREE_TYPE (t), retval);
+ gcc_unreachable ();
+ return error_mark_node;
+}
+
+/* Subroutine of cxx_eval_constant_expression.
+ Evaluate a short-circuited logical expression T in the context
+ of a given constexpr CALL. BAILOUT_VALUE is the value for
+ early return. CONTINUE_VALUE is used here purely for
+ sanity check purposes. */
+
+static tree
+cxx_eval_logical_expression (const constexpr_call *call, tree t,
+ tree bailout_value, tree continue_value,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ tree r;
+ tree lhs = cxx_eval_constant_expression (call, TREE_OPERAND (t, 0),
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ VERIFY_CONSTANT (lhs);
+ if (tree_int_cst_equal (lhs, bailout_value))
+ return lhs;
+ gcc_assert (tree_int_cst_equal (lhs, continue_value));
+ r = cxx_eval_constant_expression (call, TREE_OPERAND (t, 1),
+ allow_non_constant, addr, non_constant_p, overflow_p);
+ VERIFY_CONSTANT (r);
+ return r;
+}
+
+/* REF is a COMPONENT_REF designating a particular field. V is a vector of
+ CONSTRUCTOR elements to initialize (part of) an object containing that
+ field. Return a pointer to the constructor_elt corresponding to the
+ initialization of the field. */
+
+static constructor_elt *
+base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref)
+{
+ tree aggr = TREE_OPERAND (ref, 0);
+ tree field = TREE_OPERAND (ref, 1);
+ HOST_WIDE_INT i;
+ constructor_elt *ce;
+
+ gcc_assert (TREE_CODE (ref) == COMPONENT_REF);
+
+ if (TREE_CODE (aggr) == COMPONENT_REF)
+ {
+ constructor_elt *base_ce
+ = base_field_constructor_elt (v, aggr);
+ v = CONSTRUCTOR_ELTS (base_ce->value);
+ }
+
+ for (i = 0; vec_safe_iterate (v, i, &ce); ++i)
+ if (ce->index == field)
+ return ce;
+
+ gcc_unreachable ();
+ return NULL;
+}
+
+/* Subroutine of cxx_eval_constant_expression.
+ The expression tree T denotes a C-style array or a C-style
+ aggregate. Reduce it to a constant expression. */
+
+static tree
+cxx_eval_bare_aggregate (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t);
+ vec<constructor_elt, va_gc> *n;
+ vec_alloc (n, vec_safe_length (v));
+ constructor_elt *ce;
+ HOST_WIDE_INT i;
+ bool changed = false;
+ gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t));
+ for (i = 0; vec_safe_iterate (v, i, &ce); ++i)
+ {
+ tree elt = cxx_eval_constant_expression (call, ce->value,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ /* Don't VERIFY_CONSTANT here. */
+ if (allow_non_constant && *non_constant_p)
+ goto fail;
+ if (elt != ce->value)
+ changed = true;
+ if (ce->index && TREE_CODE (ce->index) == COMPONENT_REF)
+ {
+ /* This is an initialization of a vfield inside a base
+ subaggregate that we already initialized; push this
+ initialization into the previous initialization. */
+ constructor_elt *inner = base_field_constructor_elt (n, ce->index);
+ inner->value = elt;
+ }
+ else if (ce->index
+ && (TREE_CODE (ce->index) == NOP_EXPR
+ || TREE_CODE (ce->index) == POINTER_PLUS_EXPR))
+ {
+ /* This is an initializer for an empty base; now that we've
+ checked that it's constant, we can ignore it. */
+ gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (ce->index))));
+ }
+ else
+ CONSTRUCTOR_APPEND_ELT (n, ce->index, elt);
+ }
+ if (*non_constant_p || !changed)
+ {
+ fail:
+ vec_free (n);
+ return t;
+ }
+ t = build_constructor (TREE_TYPE (t), n);
+ TREE_CONSTANT (t) = true;
+ if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
+ t = fold (t);
+ return t;
+}
+
+/* Subroutine of cxx_eval_constant_expression.
+ The expression tree T is a VEC_INIT_EXPR which denotes the desired
+ initialization of a non-static data member of array type. Reduce it to a
+ CONSTRUCTOR.
+
+ Note that apart from value-initialization (when VALUE_INIT is true),
+ this is only intended to support value-initialization and the
+ initializations done by defaulted constructors for classes with
+ non-static data members of array type. In this case, VEC_INIT_EXPR_INIT
+ will either be NULL_TREE for the default constructor, or a COMPONENT_REF
+ for the copy/move constructor. */
+
+static tree
+cxx_eval_vec_init_1 (const constexpr_call *call, tree atype, tree init,
+ bool value_init, bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ tree elttype = TREE_TYPE (atype);
+ int max = tree_to_shwi (array_type_nelts (atype));
+ vec<constructor_elt, va_gc> *n;
+ vec_alloc (n, max + 1);
+ bool pre_init = false;
+ int i;
+
+ /* For the default constructor, build up a call to the default
+ constructor of the element type. We only need to handle class types
+ here, as for a constructor to be constexpr, all members must be
+ initialized, which for a defaulted default constructor means they must
+ be of a class type with a constexpr default constructor. */
+ if (TREE_CODE (elttype) == ARRAY_TYPE)
+ /* We only do this at the lowest level. */;
+ else if (value_init)
+ {
+ init = build_value_init (elttype, tf_warning_or_error);
+ init = cxx_eval_constant_expression
+ (call, init, allow_non_constant, addr, non_constant_p, overflow_p);
+ pre_init = true;
+ }
+ else if (!init)
+ {
+ vec<tree, va_gc> *argvec = make_tree_vector ();
+ init = build_special_member_call (NULL_TREE, complete_ctor_identifier,
+ &argvec, elttype, LOOKUP_NORMAL,
+ tf_warning_or_error);
+ release_tree_vector (argvec);
+ init = cxx_eval_constant_expression (call, init, allow_non_constant,
+ addr, non_constant_p, overflow_p);
+ pre_init = true;
+ }
+
+ if (*non_constant_p && !allow_non_constant)
+ goto fail;
+
+ for (i = 0; i <= max; ++i)
+ {
+ tree idx = build_int_cst (size_type_node, i);
+ tree eltinit;
+ if (TREE_CODE (elttype) == ARRAY_TYPE)
+ {
+ /* A multidimensional array; recurse. */
+ if (value_init || init == NULL_TREE)
+ eltinit = NULL_TREE;
+ else
+ eltinit = cp_build_array_ref (input_location, init, idx,
+ tf_warning_or_error);
+ eltinit = cxx_eval_vec_init_1 (call, elttype, eltinit, value_init,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ }
+ else if (pre_init)
+ {
+ /* Initializing an element using value or default initialization
+ we just pre-built above. */
+ if (i == 0)
+ eltinit = init;
+ else
+ eltinit = unshare_expr (init);
+ }
+ else
+ {
+ /* Copying an element. */
+ gcc_assert (same_type_ignoring_top_level_qualifiers_p
+ (atype, TREE_TYPE (init)));
+ eltinit = cp_build_array_ref (input_location, init, idx,
+ tf_warning_or_error);
+ if (!real_lvalue_p (init))
+ eltinit = move (eltinit);
+ eltinit = force_rvalue (eltinit, tf_warning_or_error);
+ eltinit = cxx_eval_constant_expression
+ (call, eltinit, allow_non_constant, addr, non_constant_p, overflow_p);
+ }
+ if (*non_constant_p && !allow_non_constant)
+ goto fail;
+ CONSTRUCTOR_APPEND_ELT (n, idx, eltinit);
+ }
+
+ if (!*non_constant_p)
+ {
+ init = build_constructor (atype, n);
+ TREE_CONSTANT (init) = true;
+ return init;
+ }
+
+ fail:
+ vec_free (n);
+ return init;
+}
+
+static tree
+cxx_eval_vec_init (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ tree atype = TREE_TYPE (t);
+ tree init = VEC_INIT_EXPR_INIT (t);
+ tree r = cxx_eval_vec_init_1 (call, atype, init,
+ VEC_INIT_EXPR_VALUE_INIT (t),
+ allow_non_constant, addr, non_constant_p, overflow_p);
+ if (*non_constant_p)
+ return t;
+ else
+ return r;
+}
+
+/* A less strict version of fold_indirect_ref_1, which requires cv-quals to
+ match. We want to be less strict for simple *& folding; if we have a
+ non-const temporary that we access through a const pointer, that should
+ work. We handle this here rather than change fold_indirect_ref_1
+ because we're dealing with things like ADDR_EXPR of INTEGER_CST which
+ don't really make sense outside of constant expression evaluation. Also
+ we want to allow folding to COMPONENT_REF, which could cause trouble
+ with TBAA in fold_indirect_ref_1.
+
+ Try to keep this function synced with fold_indirect_ref_1. */
+
+static tree
+cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base)
+{
+ tree sub, subtype;
+
+ sub = op0;
+ STRIP_NOPS (sub);
+ subtype = TREE_TYPE (sub);
+ if (!POINTER_TYPE_P (subtype))
+ return NULL_TREE;
+
+ if (TREE_CODE (sub) == ADDR_EXPR)
+ {
+ tree op = TREE_OPERAND (sub, 0);
+ tree optype = TREE_TYPE (op);
+
+ /* *&CONST_DECL -> to the value of the const decl. */
+ if (TREE_CODE (op) == CONST_DECL)
+ return DECL_INITIAL (op);
+ /* *&p => p; make sure to handle *&"str"[cst] here. */
+ if (same_type_ignoring_top_level_qualifiers_p (optype, type))
+ {
+ tree fop = fold_read_from_constant_string (op);
+ if (fop)
+ return fop;
+ else
+ return op;
+ }
+ /* *(foo *)&fooarray => fooarray[0] */
+ else if (TREE_CODE (optype) == ARRAY_TYPE
+ && (same_type_ignoring_top_level_qualifiers_p
+ (type, TREE_TYPE (optype))))
+ {
+ tree type_domain = TYPE_DOMAIN (optype);
+ tree min_val = size_zero_node;
+ if (type_domain && TYPE_MIN_VALUE (type_domain))
+ min_val = TYPE_MIN_VALUE (type_domain);
+ return build4_loc (loc, ARRAY_REF, type, op, min_val,
+ NULL_TREE, NULL_TREE);
+ }
+ /* *(foo *)&complexfoo => __real__ complexfoo */
+ else if (TREE_CODE (optype) == COMPLEX_TYPE
+ && (same_type_ignoring_top_level_qualifiers_p
+ (type, TREE_TYPE (optype))))
+ return fold_build1_loc (loc, REALPART_EXPR, type, op);
+ /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
+ else if (TREE_CODE (optype) == VECTOR_TYPE
+ && (same_type_ignoring_top_level_qualifiers_p
+ (type, TREE_TYPE (optype))))
+ {
+ tree part_width = TYPE_SIZE (type);
+ tree index = bitsize_int (0);
+ return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, index);
+ }
+ /* Also handle conversion to an empty base class, which
+ is represented with a NOP_EXPR. */
+ else if (is_empty_class (type)
+ && CLASS_TYPE_P (optype)
+ && DERIVED_FROM_P (type, optype))
+ {
+ *empty_base = true;
+ return op;
+ }
+ /* *(foo *)&struct_with_foo_field => COMPONENT_REF */
+ else if (RECORD_OR_UNION_TYPE_P (optype))
+ {
+ tree field = TYPE_FIELDS (optype);
+ for (; field; field = DECL_CHAIN (field))
+ if (TREE_CODE (field) == FIELD_DECL
+ && integer_zerop (byte_position (field))
+ && (same_type_ignoring_top_level_qualifiers_p
+ (TREE_TYPE (field), type)))
+ {
+ return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE);
+ break;
+ }
+ }
+ }
+ else if (TREE_CODE (sub) == POINTER_PLUS_EXPR
+ && TREE_CODE (TREE_OPERAND (sub, 1)) == INTEGER_CST)
+ {
+ tree op00 = TREE_OPERAND (sub, 0);
+ tree op01 = TREE_OPERAND (sub, 1);
+
+ STRIP_NOPS (op00);
+ if (TREE_CODE (op00) == ADDR_EXPR)
+ {
+ tree op00type;
+ op00 = TREE_OPERAND (op00, 0);
+ op00type = TREE_TYPE (op00);
+
+ /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
+ if (TREE_CODE (op00type) == VECTOR_TYPE
+ && (same_type_ignoring_top_level_qualifiers_p
+ (type, TREE_TYPE (op00type))))
+ {
+ HOST_WIDE_INT offset = tree_to_shwi (op01);
+ tree part_width = TYPE_SIZE (type);
+ unsigned HOST_WIDE_INT part_widthi = tree_to_shwi (part_width)/BITS_PER_UNIT;
+ unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT;
+ tree index = bitsize_int (indexi);
+
+ if (offset / part_widthi < TYPE_VECTOR_SUBPARTS (op00type))
+ return fold_build3_loc (loc,
+ BIT_FIELD_REF, type, op00,
+ part_width, index);
+
+ }
+ /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
+ else if (TREE_CODE (op00type) == COMPLEX_TYPE
+ && (same_type_ignoring_top_level_qualifiers_p
+ (type, TREE_TYPE (op00type))))
+ {
+ tree size = TYPE_SIZE_UNIT (type);
+ if (tree_int_cst_equal (size, op01))
+ return fold_build1_loc (loc, IMAGPART_EXPR, type, op00);
+ }
+ /* ((foo *)&fooarray)[1] => fooarray[1] */
+ else if (TREE_CODE (op00type) == ARRAY_TYPE
+ && (same_type_ignoring_top_level_qualifiers_p
+ (type, TREE_TYPE (op00type))))
+ {
+ tree type_domain = TYPE_DOMAIN (op00type);
+ tree min_val = size_zero_node;
+ if (type_domain && TYPE_MIN_VALUE (type_domain))
+ min_val = TYPE_MIN_VALUE (type_domain);
+ op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01,
+ TYPE_SIZE_UNIT (type));
+ op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val);
+ return build4_loc (loc, ARRAY_REF, type, op00, op01,
+ NULL_TREE, NULL_TREE);
+ }
+ /* Also handle conversion to an empty base class, which
+ is represented with a NOP_EXPR. */
+ else if (is_empty_class (type)
+ && CLASS_TYPE_P (op00type)
+ && DERIVED_FROM_P (type, op00type))
+ {
+ *empty_base = true;
+ return op00;
+ }
+ /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */
+ else if (RECORD_OR_UNION_TYPE_P (op00type))
+ {
+ tree field = TYPE_FIELDS (op00type);
+ for (; field; field = DECL_CHAIN (field))
+ if (TREE_CODE (field) == FIELD_DECL
+ && tree_int_cst_equal (byte_position (field), op01)
+ && (same_type_ignoring_top_level_qualifiers_p
+ (TREE_TYPE (field), type)))
+ {
+ return fold_build3 (COMPONENT_REF, type, op00,
+ field, NULL_TREE);
+ break;
+ }
+ }
+ }
+ }
+ /* *(foo *)fooarrptr => (*fooarrptr)[0] */
+ else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE
+ && (same_type_ignoring_top_level_qualifiers_p
+ (type, TREE_TYPE (TREE_TYPE (subtype)))))
+ {
+ tree type_domain;
+ tree min_val = size_zero_node;
+ tree newsub = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL);
+ if (newsub)
+ sub = newsub;
+ else
+ sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub);
+ type_domain = TYPE_DOMAIN (TREE_TYPE (sub));
+ if (type_domain && TYPE_MIN_VALUE (type_domain))
+ min_val = TYPE_MIN_VALUE (type_domain);
+ return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE,
+ NULL_TREE);
+ }
+
+ return NULL_TREE;
+}
+
+static tree
+cxx_eval_indirect_ref (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ tree orig_op0 = TREE_OPERAND (t, 0);
+ tree op0 = cxx_eval_constant_expression (call, orig_op0, allow_non_constant,
+ /*addr*/false, non_constant_p, overflow_p);
+ bool empty_base = false;
+ tree r;
+
+ /* Don't VERIFY_CONSTANT here. */
+ if (*non_constant_p)
+ return t;
+
+ r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0,
+ &empty_base);
+
+ if (r)
+ r = cxx_eval_constant_expression (call, r, allow_non_constant,
+ addr, non_constant_p, overflow_p);
+ else
+ {
+ tree sub = op0;
+ STRIP_NOPS (sub);
+ if (TREE_CODE (sub) == ADDR_EXPR)
+ {
+ /* We couldn't fold to a constant value. Make sure it's not
+ something we should have been able to fold. */
+ gcc_assert (!same_type_ignoring_top_level_qualifiers_p
+ (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t)));
+ /* DR 1188 says we don't have to deal with this. */
+ if (!allow_non_constant)
+ error ("accessing value of %qE through a %qT glvalue in a "
+ "constant expression", build_fold_indirect_ref (sub),
+ TREE_TYPE (t));
+ *non_constant_p = true;
+ return t;
+ }
+ }
+
+ /* If we're pulling out the value of an empty base, make sure
+ that the whole object is constant and then return an empty
+ CONSTRUCTOR. */
+ if (empty_base)
+ {
+ VERIFY_CONSTANT (r);
+ r = build_constructor (TREE_TYPE (t), NULL);
+ TREE_CONSTANT (r) = true;
+ }
+
+ if (r == NULL_TREE)
+ {
+ if (addr && op0 != orig_op0)
+ return build1 (INDIRECT_REF, TREE_TYPE (t), op0);
+ if (!addr)
+ VERIFY_CONSTANT (t);
+ return t;
+ }
+ return r;
+}
+
+/* Complain about R, a VAR_DECL, not being usable in a constant expression.
+ Shared between potential_constant_expression and
+ cxx_eval_constant_expression. */
+
+static void
+non_const_var_error (tree r)
+{
+ tree type = TREE_TYPE (r);
+ error ("the value of %qD is not usable in a constant "
+ "expression", r);
+ /* Avoid error cascade. */
+ if (DECL_INITIAL (r) == error_mark_node)
+ return;
+ if (DECL_DECLARED_CONSTEXPR_P (r))
+ inform (DECL_SOURCE_LOCATION (r),
+ "%qD used in its own initializer", r);
+ else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type))
+ {
+ if (!CP_TYPE_CONST_P (type))
+ inform (DECL_SOURCE_LOCATION (r),
+ "%q#D is not const", r);
+ else if (CP_TYPE_VOLATILE_P (type))
+ inform (DECL_SOURCE_LOCATION (r),
+ "%q#D is volatile", r);
+ else if (!DECL_INITIAL (r)
+ || !TREE_CONSTANT (DECL_INITIAL (r)))
+ inform (DECL_SOURCE_LOCATION (r),
+ "%qD was not initialized with a constant "
+ "expression", r);
+ else
+ gcc_unreachable ();
+ }
+ else
+ {
+ if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r))
+ inform (DECL_SOURCE_LOCATION (r),
+ "%qD was not declared %<constexpr%>", r);
+ else
+ inform (DECL_SOURCE_LOCATION (r),
+ "%qD does not have integral or enumeration type",
+ r);
+ }
+}
+
+/* Subroutine of cxx_eval_constant_expression.
+ Like cxx_eval_unary_expression, except for trinary expressions. */
+
+static tree
+cxx_eval_trinary_expression (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ int i;
+ tree args[3];
+ tree val;
+
+ for (i = 0; i < 3; i++)
+ {
+ args[i] = cxx_eval_constant_expression (call, TREE_OPERAND (t, i),
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ VERIFY_CONSTANT (args[i]);
+ }
+
+ val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t),
+ args[0], args[1], args[2]);
+ if (val == NULL_TREE)
+ return t;
+ VERIFY_CONSTANT (val);
+ return val;
+}
+
+bool
+var_in_constexpr_fn (tree t)
+{
+ tree ctx = DECL_CONTEXT (t);
+ return (cxx_dialect >= cxx14 && ctx && TREE_CODE (ctx) == FUNCTION_DECL
+ && DECL_DECLARED_CONSTEXPR_P (ctx));
+}
+
+/* Attempt to reduce the expression T to a constant value.
+ On failure, issue diagnostic and return error_mark_node. */
+/* FIXME unify with c_fully_fold */
+
+static tree
+cxx_eval_constant_expression (const constexpr_call *call, tree t,
+ bool allow_non_constant, bool addr,
+ bool *non_constant_p, bool *overflow_p)
+{
+ tree r = t;
+
+ if (t == error_mark_node)
+ {
+ *non_constant_p = true;
+ return t;
+ }
+ if (CONSTANT_CLASS_P (t))
+ {
+ if (TREE_CODE (t) == PTRMEM_CST)
+ t = cplus_expand_constant (t);
+ else if (TREE_OVERFLOW (t) && (!flag_permissive || allow_non_constant))
+ *overflow_p = true;
+ return t;
+ }
+ if (TREE_CODE (t) != NOP_EXPR
+ && reduced_constant_expression_p (t))
+ return fold (t);
+
+ switch (TREE_CODE (t))
+ {
+ case VAR_DECL:
+ if (addr)
+ return t;
+ /* else fall through. */
+ case CONST_DECL:
+ r = integral_constant_value (t);
+ if (TREE_CODE (r) == TARGET_EXPR
+ && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR)
+ r = TARGET_EXPR_INITIAL (r);
+ if (DECL_P (r) && var_in_constexpr_fn (r)
+ && DECL_INITIAL (r))
+ r = cxx_eval_constant_expression (call, DECL_INITIAL (r),
+ allow_non_constant, false,
+ non_constant_p, overflow_p);
+ if (DECL_P (r))
+ {
+ if (!allow_non_constant)
+ non_const_var_error (r);
+ *non_constant_p = true;
+ }
+ break;
+
+ case FUNCTION_DECL:
+ case TEMPLATE_DECL:
+ case LABEL_DECL:
+ return t;
+
+ case PARM_DECL:
+ if (call && DECL_CONTEXT (t) == call->fundef->decl)
+ {
+ if (DECL_ARTIFICIAL (t) && DECL_CONSTRUCTOR_P (DECL_CONTEXT (t)))
+ {
+ if (!allow_non_constant)
+ sorry ("use of the value of the object being constructed "
+ "in a constant expression");
+ *non_constant_p = true;
+ }
+ else
+ r = lookup_parameter_binding (call, t);
+ }
+ else if (addr)
+ /* Defer in case this is only used for its type. */;
+ else
+ {
+ if (!allow_non_constant)
+ error ("%qE is not a constant expression", t);
+ *non_constant_p = true;
+ }
+ break;
+
+ case CALL_EXPR:
+ case AGGR_INIT_EXPR:
+ r = cxx_eval_call_expression (call, t, allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case TARGET_EXPR:
+ if (!literal_type_p (TREE_TYPE (t)))
+ {
+ if (!allow_non_constant)
+ {
+ error ("temporary of non-literal type %qT in a "
+ "constant expression", TREE_TYPE (t));
+ explain_non_literal_class (TREE_TYPE (t));
+ }
+ *non_constant_p = true;
+ break;
+ }
+ /* else fall through. */
+ case INIT_EXPR:
+ /* Pass false for 'addr' because these codes indicate
+ initialization of a temporary. */
+ r = cxx_eval_constant_expression (call, TREE_OPERAND (t, 1),
+ allow_non_constant, false,
+ non_constant_p, overflow_p);
+ if (!*non_constant_p)
+ /* Adjust the type of the result to the type of the temporary. */
+ r = adjust_temp_type (TREE_TYPE (t), r);
+ break;
+
+ case SCOPE_REF:
+ r = cxx_eval_constant_expression (call, TREE_OPERAND (t, 1),
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case RETURN_EXPR:
+ case NON_LVALUE_EXPR:
+ case TRY_CATCH_EXPR:
+ case CLEANUP_POINT_EXPR:
+ case MUST_NOT_THROW_EXPR:
+ case SAVE_EXPR:
+ r = cxx_eval_constant_expression (call, TREE_OPERAND (t, 0),
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ /* These differ from cxx_eval_unary_expression in that this doesn't
+ check for a constant operand or result; an address can be
+ constant without its operand being, and vice versa. */
+ case INDIRECT_REF:
+ r = cxx_eval_indirect_ref (call, t, allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case ADDR_EXPR:
+ {
+ tree oldop = TREE_OPERAND (t, 0);
+ tree op = cxx_eval_constant_expression (call, oldop,
+ allow_non_constant,
+ /*addr*/true,
+ non_constant_p, overflow_p);
+ /* Don't VERIFY_CONSTANT here. */
+ if (*non_constant_p)
+ return t;
+ /* This function does more aggressive folding than fold itself. */
+ r = build_fold_addr_expr_with_type (op, TREE_TYPE (t));
+ if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop)
+ return t;
+ break;
+ }
+
+ case REALPART_EXPR:
+ case IMAGPART_EXPR:
+ case CONJ_EXPR:
+ case FIX_TRUNC_EXPR:
+ case FLOAT_EXPR:
+ case NEGATE_EXPR:
+ case ABS_EXPR:
+ case BIT_NOT_EXPR:
+ case TRUTH_NOT_EXPR:
+ case FIXED_CONVERT_EXPR:
+ r = cxx_eval_unary_expression (call, t, allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case SIZEOF_EXPR:
+ if (SIZEOF_EXPR_TYPE_P (t))
+ r = cxx_sizeof_or_alignof_type (TREE_TYPE (TREE_OPERAND (t, 0)),
+ SIZEOF_EXPR, false);
+ else if (TYPE_P (TREE_OPERAND (t, 0)))
+ r = cxx_sizeof_or_alignof_type (TREE_OPERAND (t, 0), SIZEOF_EXPR,
+ false);
+ else
+ r = cxx_sizeof_or_alignof_expr (TREE_OPERAND (t, 0), SIZEOF_EXPR,
+ false);
+ if (r == error_mark_node)
+ r = size_one_node;
+ VERIFY_CONSTANT (r);
+ break;
+
+ case COMPOUND_EXPR:
+ {
+ /* check_return_expr sometimes wraps a TARGET_EXPR in a
+ COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR
+ introduced by build_call_a. */
+ tree op0 = TREE_OPERAND (t, 0);
+ tree op1 = TREE_OPERAND (t, 1);
+ STRIP_NOPS (op1);
+ if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0))
+ || TREE_CODE (op1) == EMPTY_CLASS_EXPR)
+ r = cxx_eval_constant_expression (call, op0, allow_non_constant,
+ addr, non_constant_p, overflow_p);
+ else
+ {
+ /* Check that the LHS is constant and then discard it. */
+ cxx_eval_constant_expression (call, op0, allow_non_constant,
+ false, non_constant_p, overflow_p);
+ op1 = TREE_OPERAND (t, 1);
+ r = cxx_eval_constant_expression (call, op1, allow_non_constant,
+ addr, non_constant_p, overflow_p);
+ }
+ }
+ break;
+
+ case POINTER_PLUS_EXPR:
+ case PLUS_EXPR:
+ case MINUS_EXPR:
+ case MULT_EXPR:
+ case TRUNC_DIV_EXPR:
+ case CEIL_DIV_EXPR:
+ case FLOOR_DIV_EXPR:
+ case ROUND_DIV_EXPR:
+ case TRUNC_MOD_EXPR:
+ case CEIL_MOD_EXPR:
+ case ROUND_MOD_EXPR:
+ case RDIV_EXPR:
+ case EXACT_DIV_EXPR:
+ case MIN_EXPR:
+ case MAX_EXPR:
+ case LSHIFT_EXPR:
+ case RSHIFT_EXPR:
+ case LROTATE_EXPR:
+ case RROTATE_EXPR:
+ case BIT_IOR_EXPR:
+ case BIT_XOR_EXPR:
+ case BIT_AND_EXPR:
+ case TRUTH_XOR_EXPR:
+ case LT_EXPR:
+ case LE_EXPR:
+ case GT_EXPR:
+ case GE_EXPR:
+ case EQ_EXPR:
+ case NE_EXPR:
+ case UNORDERED_EXPR:
+ case ORDERED_EXPR:
+ case UNLT_EXPR:
+ case UNLE_EXPR:
+ case UNGT_EXPR:
+ case UNGE_EXPR:
+ case UNEQ_EXPR:
+ case LTGT_EXPR:
+ case RANGE_EXPR:
+ case COMPLEX_EXPR:
+ r = cxx_eval_binary_expression (call, t, allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ /* fold can introduce non-IF versions of these; still treat them as
+ short-circuiting. */
+ case TRUTH_AND_EXPR:
+ case TRUTH_ANDIF_EXPR:
+ r = cxx_eval_logical_expression (call, t, boolean_false_node,
+ boolean_true_node,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case TRUTH_OR_EXPR:
+ case TRUTH_ORIF_EXPR:
+ r = cxx_eval_logical_expression (call, t, boolean_true_node,
+ boolean_false_node,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case ARRAY_REF:
+ r = cxx_eval_array_reference (call, t, allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case COMPONENT_REF:
+ if (is_overloaded_fn (t))
+ {
+ /* We can only get here in checking mode via
+ build_non_dependent_expr, because any expression that
+ calls or takes the address of the function will have
+ pulled a FUNCTION_DECL out of the COMPONENT_REF. */
+ gcc_checking_assert (allow_non_constant || errorcount);
+ *non_constant_p = true;
+ return t;
+ }
+ r = cxx_eval_component_reference (call, t, allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case BIT_FIELD_REF:
+ r = cxx_eval_bit_field_ref (call, t, allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case COND_EXPR:
+ case VEC_COND_EXPR:
+ r = cxx_eval_conditional_expression (call, t, allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case CONSTRUCTOR:
+ r = cxx_eval_bare_aggregate (call, t, allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case VEC_INIT_EXPR:
+ /* We can get this in a defaulted constructor for a class with a
+ non-static data member of array type. Either the initializer will
+ be NULL, meaning default-initialization, or it will be an lvalue
+ or xvalue of the same type, meaning direct-initialization from the
+ corresponding member. */
+ r = cxx_eval_vec_init (call, t, allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case FMA_EXPR:
+ case VEC_PERM_EXPR:
+ r = cxx_eval_trinary_expression (call, t, allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ break;
+
+ case CONVERT_EXPR:
+ case VIEW_CONVERT_EXPR:
+ case NOP_EXPR:
+ {
+ tree oldop = TREE_OPERAND (t, 0);
+ tree op = cxx_eval_constant_expression (call, oldop,
+ allow_non_constant, addr,
+ non_constant_p, overflow_p);
+ if (*non_constant_p)
+ return t;
+ if (POINTER_TYPE_P (TREE_TYPE (t))
+ && TREE_CODE (op) == INTEGER_CST
+ && !integer_zerop (op))
+ {
+ if (!allow_non_constant)
+ error_at (EXPR_LOC_OR_LOC (t, input_location),
+ "reinterpret_cast from integer to pointer");
+ *non_constant_p = true;
+ return t;
+ }
+ if (op == oldop)
+ /* We didn't fold at the top so we could check for ptr-int
+ conversion. */
+ return fold (t);
+ r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), op);
+ /* Conversion of an out-of-range value has implementation-defined
+ behavior; the language considers it different from arithmetic
+ overflow, which is undefined. */
+ if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op))
+ TREE_OVERFLOW (r) = false;
+ }
+ break;
+
+ case EMPTY_CLASS_EXPR:
+ /* This is good enough for a function argument that might not get
+ used, and they can't do anything with it, so just return it. */
+ return t;
+
+ case LAMBDA_EXPR:
+ case PREINCREMENT_EXPR:
+ case POSTINCREMENT_EXPR:
+ case PREDECREMENT_EXPR:
+ case POSTDECREMENT_EXPR:
+ case NEW_EXPR:
+ case VEC_NEW_EXPR:
+ case DELETE_EXPR:
+ case VEC_DELETE_EXPR:
+ case THROW_EXPR:
+ case MODIFY_EXPR:
+ case MODOP_EXPR:
+ /* GCC internal stuff. */
+ case VA_ARG_EXPR:
+ case OBJ_TYPE_REF:
+ case WITH_CLEANUP_EXPR:
+ case STATEMENT_LIST:
+ case BIND_EXPR:
+ case NON_DEPENDENT_EXPR:
+ case BASELINK:
+ case EXPR_STMT:
+ case OFFSET_REF:
+ if (!allow_non_constant)
+ error_at (EXPR_LOC_OR_LOC (t, input_location),
+ "expression %qE is not a constant-expression", t);
+ *non_constant_p = true;
+ break;
+
+ default:
+ internal_error ("unexpected expression %qE of kind %s", t,
+ get_tree_code_name (TREE_CODE (t)));
+ *non_constant_p = true;
+ break;
+ }
+
+ if (r == error_mark_node)
+ *non_constant_p = true;
+
+ if (*non_constant_p)
+ return t;
+ else
+ return r;
+}
+
+static tree
+cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant)
+{
+ bool non_constant_p = false;
+ bool overflow_p = false;
+ tree r = cxx_eval_constant_expression (NULL, t, allow_non_constant,
+ false, &non_constant_p, &overflow_p);
+
+ verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p);
+
+ if (TREE_CODE (t) != CONSTRUCTOR
+ && cp_has_mutable_p (TREE_TYPE (t)))
+ {
+ /* We allow a mutable type if the original expression was a
+ CONSTRUCTOR so that we can do aggregate initialization of
+ constexpr variables. */
+ if (!allow_non_constant)
+ error ("%qT cannot be the type of a complete constant expression "
+ "because it has mutable sub-objects", TREE_TYPE (t));
+ non_constant_p = true;
+ }
+
+ /* Technically we should check this for all subexpressions, but that
+ runs into problems with our internal representation of pointer
+ subtraction and the 5.19 rules are still in flux. */
+ if (CONVERT_EXPR_CODE_P (TREE_CODE (r))
+ && ARITHMETIC_TYPE_P (TREE_TYPE (r))
+ && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR)
+ {
+ if (!allow_non_constant)
+ error ("conversion from pointer type %qT "
+ "to arithmetic type %qT in a constant-expression",
+ TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r));
+ non_constant_p = true;
+ }
+
+ if (!non_constant_p && overflow_p)
+ non_constant_p = true;
+
+ if (non_constant_p && !allow_non_constant)
+ return error_mark_node;
+ else if (non_constant_p && TREE_CONSTANT (r))
+ {
+ /* This isn't actually constant, so unset TREE_CONSTANT. */
+ if (EXPR_P (r))
+ r = copy_node (r);
+ else if (TREE_CODE (r) == CONSTRUCTOR)
+ r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r);
+ else
+ r = build_nop (TREE_TYPE (r), r);
+ TREE_CONSTANT (r) = false;
+ }
+ else if (non_constant_p || r == t)
+ return t;
+
+ if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r)))
+ {
+ if (TREE_CODE (t) == TARGET_EXPR
+ && TARGET_EXPR_INITIAL (t) == r)
+ return t;
+ else
+ {
+ r = get_target_expr (r);
+ TREE_CONSTANT (r) = true;
+ return r;
+ }
+ }
+ else
+ return r;
+}
+
+/* Returns true if T is a valid subexpression of a constant expression,
+ even if it isn't itself a constant expression. */
+
+bool
+is_sub_constant_expr (tree t)
+{
+ bool non_constant_p = false;
+ bool overflow_p = false;
+ cxx_eval_constant_expression (NULL, t, true, false, &non_constant_p,
+ &overflow_p);
+ return !non_constant_p && !overflow_p;
+}
+
+/* If T represents a constant expression returns its reduced value.
+ Otherwise return error_mark_node. If T is dependent, then
+ return NULL. */
+
+tree
+cxx_constant_value (tree t)
+{
+ return cxx_eval_outermost_constant_expr (t, false);
+}
+
+/* If T is a constant expression, returns its reduced value.
+ Otherwise, if T does not have TREE_CONSTANT set, returns T.
+ Otherwise, returns a version of T without TREE_CONSTANT. */
+
+tree
+maybe_constant_value (tree t)
+{
+ tree r;
+
+ if (instantiation_dependent_expression_p (t)
+ || type_unknown_p (t)
+ || BRACE_ENCLOSED_INITIALIZER_P (t)
+ || !potential_constant_expression (t))
+ {
+ if (TREE_OVERFLOW_P (t))
+ {
+ t = build_nop (TREE_TYPE (t), t);
+ TREE_CONSTANT (t) = false;
+ }
+ return t;
+ }
+
+ r = cxx_eval_outermost_constant_expr (t, true);
+#ifdef ENABLE_CHECKING
+ /* cp_tree_equal looks through NOPs, so allow them. */
+ gcc_assert (r == t
+ || CONVERT_EXPR_P (t)
+ || (TREE_CONSTANT (t) && !TREE_CONSTANT (r))
+ || !cp_tree_equal (r, t));
+#endif
+ return r;
+}
+
+/* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather
+ than wrapped in a TARGET_EXPR. */
+
+tree
+maybe_constant_init (tree t)
+{
+ if (TREE_CODE (t) == EXPR_STMT)
+ t = TREE_OPERAND (t, 0);
+ if (TREE_CODE (t) == CONVERT_EXPR
+ && VOID_TYPE_P (TREE_TYPE (t)))
+ t = TREE_OPERAND (t, 0);
+ t = maybe_constant_value (t);
+ if (TREE_CODE (t) == TARGET_EXPR)
+ {
+ tree init = TARGET_EXPR_INITIAL (t);
+ if (TREE_CODE (init) == CONSTRUCTOR)
+ t = init;
+ }
+ return t;
+}
+
+#if 0
+/* FIXME see ADDR_EXPR section in potential_constant_expression_1. */
+/* Return true if the object referred to by REF has automatic or thread
+ local storage. */
+
+enum { ck_ok, ck_bad, ck_unknown };
+static int
+check_automatic_or_tls (tree ref)
+{
+ enum machine_mode mode;
+ HOST_WIDE_INT bitsize, bitpos;
+ tree offset;
+ int volatilep = 0, unsignedp = 0;
+ tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset,
+ &mode, &unsignedp, &volatilep, false);
+ duration_kind dk;
+
+ /* If there isn't a decl in the middle, we don't know the linkage here,
+ and this isn't a constant expression anyway. */
+ if (!DECL_P (decl))
+ return ck_unknown;
+ dk = decl_storage_duration (decl);
+ return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok;
+}
+#endif
+
+/* Return true if T denotes a potentially constant expression. Issue
+ diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true,
+ an lvalue-rvalue conversion is implied.
+
+ C++0x [expr.const] used to say
+
+ 6 An expression is a potential constant expression if it is
+ a constant expression where all occurrences of function
+ parameters are replaced by arbitrary constant expressions
+ of the appropriate type.
+
+ 2 A conditional expression is a constant expression unless it
+ involves one of the following as a potentially evaluated
+ subexpression (3.2), but subexpressions of logical AND (5.14),
+ logical OR (5.15), and conditional (5.16) operations that are
+ not evaluated are not considered. */
+
+static bool
+potential_constant_expression_1 (tree t, bool want_rval, tsubst_flags_t flags)
+{
+ enum { any = false, rval = true };
+ int i;
+ tree tmp;
+
+ if (t == error_mark_node)
+ return false;
+ if (t == NULL_TREE)
+ return true;
+ if (TREE_THIS_VOLATILE (t))
+ {
+ if (flags & tf_error)
+ error ("expression %qE has side-effects", t);
+ return false;
+ }
+ if (CONSTANT_CLASS_P (t))
+ return true;
+
+ switch (TREE_CODE (t))
+ {
+ case FUNCTION_DECL:
+ case BASELINK:
+ case TEMPLATE_DECL:
+ case OVERLOAD:
+ case TEMPLATE_ID_EXPR:
+ case LABEL_DECL:
+ case LABEL_EXPR:
+ case CONST_DECL:
+ case SIZEOF_EXPR:
+ case ALIGNOF_EXPR:
+ case OFFSETOF_EXPR:
+ case NOEXCEPT_EXPR:
+ case TEMPLATE_PARM_INDEX:
+ case TRAIT_EXPR:
+ case IDENTIFIER_NODE:
+ case USERDEF_LITERAL:
+ /* We can see a FIELD_DECL in a pointer-to-member expression. */
+ case FIELD_DECL:
+ case PARM_DECL:
+ case USING_DECL:
+ return true;
+
+ case AGGR_INIT_EXPR:
+ case CALL_EXPR:
+ /* -- an invocation of a function other than a constexpr function
+ or a constexpr constructor. */
+ {
+ tree fun = get_function_named_in_call (t);
+ const int nargs = call_expr_nargs (t);
+ i = 0;
+
+ if (is_overloaded_fn (fun))
+ {
+ if (TREE_CODE (fun) == FUNCTION_DECL)
+ {
+ if (builtin_valid_in_constant_expr_p (fun))
+ return true;
+ if (!DECL_DECLARED_CONSTEXPR_P (fun)
+ /* Allow any built-in function; if the expansion
+ isn't constant, we'll deal with that then. */
+ && !is_builtin_fn (fun))
+ {
+ if (flags & tf_error)
+ {
+ error_at (EXPR_LOC_OR_LOC (t, input_location),
+ "call to non-constexpr function %qD", fun);
+ explain_invalid_constexpr_fn (fun);
+ }
+ return false;
+ }
+ /* A call to a non-static member function takes the address
+ of the object as the first argument. But in a constant
+ expression the address will be folded away, so look
+ through it now. */
+ if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun)
+ && !DECL_CONSTRUCTOR_P (fun))
+ {
+ tree x = get_nth_callarg (t, 0);
+ if (is_this_parameter (x))
+ {
+ if (DECL_CONTEXT (x) == NULL_TREE
+ || DECL_CONSTRUCTOR_P (DECL_CONTEXT (x)))
+ {
+ if (flags & tf_error)
+ sorry ("calling a member function of the "
+ "object being constructed in a constant "
+ "expression");
+ return false;
+ }
+ /* Otherwise OK. */;
+ }
+ else if (!potential_constant_expression_1 (x, rval, flags))
+ return false;
+ i = 1;
+ }
+ }
+ else
+ {
+ if (!potential_constant_expression_1 (fun, true, flags))
+ return false;
+ fun = get_first_fn (fun);
+ }
+ /* Skip initial arguments to base constructors. */
+ if (DECL_BASE_CONSTRUCTOR_P (fun))
+ i = num_artificial_parms_for (fun);
+ fun = DECL_ORIGIN (fun);
+ }
+ else
+ {
+ if (potential_constant_expression_1 (fun, rval, flags))
+ /* Might end up being a constant function pointer. */;
+ else
+ return false;
+ }
+ for (; i < nargs; ++i)
+ {
+ tree x = get_nth_callarg (t, i);
+ if (!potential_constant_expression_1 (x, rval, flags))
+ return false;
+ }
+ return true;
+ }
+
+ case NON_LVALUE_EXPR:
+ /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to
+ -- an lvalue of integral type that refers to a non-volatile
+ const variable or static data member initialized with
+ constant expressions, or
+
+ -- an lvalue of literal type that refers to non-volatile
+ object defined with constexpr, or that refers to a
+ sub-object of such an object; */
+ return potential_constant_expression_1 (TREE_OPERAND (t, 0), rval, flags);
+
+ case VAR_DECL:
+ if (want_rval && !decl_constant_var_p (t)
+ && !var_in_constexpr_fn (t)
+ && !dependent_type_p (TREE_TYPE (t)))
+ {
+ if (flags & tf_error)
+ non_const_var_error (t);
+ return false;
+ }
+ return true;
+
+ case NOP_EXPR:
+ case CONVERT_EXPR:
+ case VIEW_CONVERT_EXPR:
+ /* -- a reinterpret_cast. FIXME not implemented, and this rule
+ may change to something more specific to type-punning (DR 1312). */
+ {
+ tree from = TREE_OPERAND (t, 0);
+ if (POINTER_TYPE_P (TREE_TYPE (t))
+ && TREE_CODE (from) == INTEGER_CST
+ && !integer_zerop (from))
+ {
+ if (flags & tf_error)
+ error_at (EXPR_LOC_OR_LOC (t, input_location),
+ "reinterpret_cast from integer to pointer");
+ return false;
+ }
+ return (potential_constant_expression_1
+ (from, TREE_CODE (t) != VIEW_CONVERT_EXPR, flags));
+ }
+
+ case ADDR_EXPR:
+ /* -- a unary operator & that is applied to an lvalue that
+ designates an object with thread or automatic storage
+ duration; */
+ t = TREE_OPERAND (t, 0);
+
+ if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t))
+ /* A pointer-to-member constant. */
+ return true;
+
+#if 0
+ /* FIXME adjust when issue 1197 is fully resolved. For now don't do
+ any checking here, as we might dereference the pointer later. If
+ we remove this code, also remove check_automatic_or_tls. */
+ i = check_automatic_or_tls (t);
+ if (i == ck_ok)
+ return true;
+ if (i == ck_bad)
+ {
+ if (flags & tf_error)
+ error ("address-of an object %qE with thread local or "
+ "automatic storage is not a constant expression", t);
+ return false;
+ }
+#endif
+ return potential_constant_expression_1 (t, any, flags);
+
+ case COMPONENT_REF:
+ case BIT_FIELD_REF:
+ case ARROW_EXPR:
+ case OFFSET_REF:
+ /* -- a class member access unless its postfix-expression is
+ of literal type or of pointer to literal type. */
+ /* This test would be redundant, as it follows from the
+ postfix-expression being a potential constant expression. */
+ return potential_constant_expression_1 (TREE_OPERAND (t, 0),
+ want_rval, flags);
+
+ case EXPR_PACK_EXPANSION:
+ return potential_constant_expression_1 (PACK_EXPANSION_PATTERN (t),
+ want_rval, flags);
+
+ case INDIRECT_REF:
+ {
+ tree x = TREE_OPERAND (t, 0);
+ STRIP_NOPS (x);
+ if (is_this_parameter (x))
+ {
+ if (DECL_CONTEXT (x)
+ && !DECL_DECLARED_CONSTEXPR_P (DECL_CONTEXT (x)))
+ {
+ if (flags & tf_error)
+ error ("use of %<this%> in a constant expression");
+ return false;
+ }
+ if (want_rval && DECL_CONTEXT (x)
+ && DECL_CONSTRUCTOR_P (DECL_CONTEXT (x)))
+ {
+ if (flags & tf_error)
+ sorry ("use of the value of the object being constructed "
+ "in a constant expression");
+ return false;
+ }
+ return true;
+ }
+ return potential_constant_expression_1 (x, rval, flags);
+ }
+
+ case LAMBDA_EXPR:
+ case DYNAMIC_CAST_EXPR:
+ case PSEUDO_DTOR_EXPR:
+ case PREINCREMENT_EXPR:
+ case POSTINCREMENT_EXPR:
+ case PREDECREMENT_EXPR:
+ case POSTDECREMENT_EXPR:
+ case NEW_EXPR:
+ case VEC_NEW_EXPR:
+ case DELETE_EXPR:
+ case VEC_DELETE_EXPR:
+ case THROW_EXPR:
+ case MODIFY_EXPR:
+ case MODOP_EXPR:
+ case OMP_ATOMIC:
+ case OMP_ATOMIC_READ:
+ case OMP_ATOMIC_CAPTURE_OLD:
+ case OMP_ATOMIC_CAPTURE_NEW:
+ /* GCC internal stuff. */
+ case VA_ARG_EXPR:
+ case OBJ_TYPE_REF:
+ case WITH_CLEANUP_EXPR:
+ case CLEANUP_POINT_EXPR:
+ case MUST_NOT_THROW_EXPR:
+ case TRY_CATCH_EXPR:
+ case STATEMENT_LIST:
+ /* Don't bother trying to define a subset of statement-expressions to
+ be constant-expressions, at least for now. */
+ case STMT_EXPR:
+ case EXPR_STMT:
+ case BIND_EXPR:
+ case TRANSACTION_EXPR:
+ case IF_STMT:
+ case DO_STMT:
+ case FOR_STMT:
+ case WHILE_STMT:
+ case DECL_EXPR:
+ if (flags & tf_error)
+ error ("expression %qE is not a constant-expression", t);
+ return false;
+
+ case TYPEID_EXPR:
+ /* -- a typeid expression whose operand is of polymorphic
+ class type; */
+ {
+ tree e = TREE_OPERAND (t, 0);
+ if (!TYPE_P (e) && !type_dependent_expression_p (e)
+ && TYPE_POLYMORPHIC_P (TREE_TYPE (e)))
+ {
+ if (flags & tf_error)
+ error ("typeid-expression is not a constant expression "
+ "because %qE is of polymorphic type", e);
+ return false;
+ }
+ return true;
+ }
+
+ case MINUS_EXPR:
+ /* -- a subtraction where both operands are pointers. */
+ if (TYPE_PTR_P (TREE_OPERAND (t, 0))
+ && TYPE_PTR_P (TREE_OPERAND (t, 1)))
+ {
+ if (flags & tf_error)
+ error ("difference of two pointer expressions is not "
+ "a constant expression");
+ return false;
+ }
+ want_rval = true;
+ goto binary;
+
+ case LT_EXPR:
+ case LE_EXPR:
+ case GT_EXPR:
+ case GE_EXPR:
+ case EQ_EXPR:
+ case NE_EXPR:
+ /* -- a relational or equality operator where at least
+ one of the operands is a pointer. */
+ if (TYPE_PTR_P (TREE_OPERAND (t, 0))
+ || TYPE_PTR_P (TREE_OPERAND (t, 1)))
+ {
+ if (flags & tf_error)
+ error ("pointer comparison expression is not a "
+ "constant expression");
+ return false;
+ }
+ want_rval = true;
+ goto binary;
+
+ case BIT_NOT_EXPR:
+ /* A destructor. */
+ if (TYPE_P (TREE_OPERAND (t, 0)))
+ return true;
+ /* else fall through. */
+
+ case REALPART_EXPR:
+ case IMAGPART_EXPR:
+ case CONJ_EXPR:
+ case SAVE_EXPR:
+ case FIX_TRUNC_EXPR:
+ case FLOAT_EXPR:
+ case NEGATE_EXPR:
+ case ABS_EXPR:
+ case TRUTH_NOT_EXPR:
+ case FIXED_CONVERT_EXPR:
+ case UNARY_PLUS_EXPR:
+ return potential_constant_expression_1 (TREE_OPERAND (t, 0), rval,
+ flags);
+
+ case CAST_EXPR:
+ case CONST_CAST_EXPR:
+ case STATIC_CAST_EXPR:
+ case REINTERPRET_CAST_EXPR:
+ case IMPLICIT_CONV_EXPR:
+ if (cxx_dialect < cxx11
+ && !dependent_type_p (TREE_TYPE (t))
+ && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t)))
+ /* In C++98, a conversion to non-integral type can't be part of a
+ constant expression. */
+ {
+ if (flags & tf_error)
+ error ("cast to non-integral type %qT in a constant expression",
+ TREE_TYPE (t));
+ return false;
+ }
+
+ return (potential_constant_expression_1
+ (TREE_OPERAND (t, 0),
+ TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE, flags));
+
+ case PAREN_EXPR:
+ case NON_DEPENDENT_EXPR:
+ /* For convenience. */
+ case RETURN_EXPR:
+ return potential_constant_expression_1 (TREE_OPERAND (t, 0),
+ want_rval, flags);
+
+ case SCOPE_REF:
+ return potential_constant_expression_1 (TREE_OPERAND (t, 1),
+ want_rval, flags);
+
+ case TARGET_EXPR:
+ if (!literal_type_p (TREE_TYPE (t)))
+ {
+ if (flags & tf_error)
+ {
+ error ("temporary of non-literal type %qT in a "
+ "constant expression", TREE_TYPE (t));
+ explain_non_literal_class (TREE_TYPE (t));
+ }
+ return false;
+ }
+ case INIT_EXPR:
+ return potential_constant_expression_1 (TREE_OPERAND (t, 1),
+ rval, flags);
+
+ case CONSTRUCTOR:
+ {
+ vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t);
+ constructor_elt *ce;
+ for (i = 0; vec_safe_iterate (v, i, &ce); ++i)
+ if (!potential_constant_expression_1 (ce->value, want_rval, flags))
+ return false;
+ return true;
+ }
+
+ case TREE_LIST:
+ {
+ gcc_assert (TREE_PURPOSE (t) == NULL_TREE
+ || DECL_P (TREE_PURPOSE (t)));
+ if (!potential_constant_expression_1 (TREE_VALUE (t), want_rval,
+ flags))
+ return false;
+ if (TREE_CHAIN (t) == NULL_TREE)
+ return true;
+ return potential_constant_expression_1 (TREE_CHAIN (t), want_rval,
+ flags);
+ }
+
+ case TRUNC_DIV_EXPR:
+ case CEIL_DIV_EXPR:
+ case FLOOR_DIV_EXPR:
+ case ROUND_DIV_EXPR:
+ case TRUNC_MOD_EXPR:
+ case CEIL_MOD_EXPR:
+ case ROUND_MOD_EXPR:
+ {
+ tree denom = TREE_OPERAND (t, 1);
+ if (!potential_constant_expression_1 (denom, rval, flags))
+ return false;
+ /* We can't call cxx_eval_outermost_constant_expr on an expression
+ that hasn't been through fold_non_dependent_expr yet. */
+ if (!processing_template_decl)
+ denom = cxx_eval_outermost_constant_expr (denom, true);
+ if (integer_zerop (denom))
+ {
+ if (flags & tf_error)
+ error ("division by zero is not a constant-expression");
+ return false;
+ }
+ else
+ {
+ want_rval = true;
+ return potential_constant_expression_1 (TREE_OPERAND (t, 0),
+ want_rval, flags);
+ }
+ }
+
+ case COMPOUND_EXPR:
+ {
+ /* check_return_expr sometimes wraps a TARGET_EXPR in a
+ COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR
+ introduced by build_call_a. */
+ tree op0 = TREE_OPERAND (t, 0);
+ tree op1 = TREE_OPERAND (t, 1);
+ STRIP_NOPS (op1);
+ if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0))
+ || TREE_CODE (op1) == EMPTY_CLASS_EXPR)
+ return potential_constant_expression_1 (op0, want_rval, flags);
+ else
+ goto binary;
+ }
+
+ /* If the first operand is the non-short-circuit constant, look at
+ the second operand; otherwise we only care about the first one for
+ potentiality. */
+ case TRUTH_AND_EXPR:
+ case TRUTH_ANDIF_EXPR:
+ tmp = boolean_true_node;
+ goto truth;
+ case TRUTH_OR_EXPR:
+ case TRUTH_ORIF_EXPR:
+ tmp = boolean_false_node;
+ truth:
+ {
+ tree op = TREE_OPERAND (t, 0);
+ if (!potential_constant_expression_1 (op, rval, flags))
+ return false;
+ if (!processing_template_decl)
+ op = cxx_eval_outermost_constant_expr (op, true);
+ if (tree_int_cst_equal (op, tmp))
+ return potential_constant_expression_1 (TREE_OPERAND (t, 1), rval, flags);
+ else
+ return true;
+ }
+
+ case PLUS_EXPR:
+ case MULT_EXPR:
+ case POINTER_PLUS_EXPR:
+ case RDIV_EXPR:
+ case EXACT_DIV_EXPR:
+ case MIN_EXPR:
+ case MAX_EXPR:
+ case LSHIFT_EXPR:
+ case RSHIFT_EXPR:
+ case LROTATE_EXPR:
+ case RROTATE_EXPR:
+ case BIT_IOR_EXPR:
+ case BIT_XOR_EXPR:
+ case BIT_AND_EXPR:
+ case TRUTH_XOR_EXPR:
+ case UNORDERED_EXPR:
+ case ORDERED_EXPR:
+ case UNLT_EXPR:
+ case UNLE_EXPR:
+ case UNGT_EXPR:
+ case UNGE_EXPR:
+ case UNEQ_EXPR:
+ case LTGT_EXPR:
+ case RANGE_EXPR:
+ case COMPLEX_EXPR:
+ want_rval = true;
+ /* Fall through. */
+ case ARRAY_REF:
+ case ARRAY_RANGE_REF:
+ case MEMBER_REF:
+ case DOTSTAR_EXPR:
+ binary:
+ for (i = 0; i < 2; ++i)
+ if (!potential_constant_expression_1 (TREE_OPERAND (t, i),
+ want_rval, flags))
+ return false;
+ return true;
+
+ case CILK_SYNC_STMT:
+ case CILK_SPAWN_STMT:
+ case ARRAY_NOTATION_REF:
+ return false;
+
+ case FMA_EXPR:
+ case VEC_PERM_EXPR:
+ for (i = 0; i < 3; ++i)
+ if (!potential_constant_expression_1 (TREE_OPERAND (t, i),
+ true, flags))
+ return false;
+ return true;
+
+ case COND_EXPR:
+ case VEC_COND_EXPR:
+ /* If the condition is a known constant, we know which of the legs we
+ care about; otherwise we only require that the condition and
+ either of the legs be potentially constant. */
+ tmp = TREE_OPERAND (t, 0);
+ if (!potential_constant_expression_1 (tmp, rval, flags))
+ return false;
+ if (!processing_template_decl)
+ tmp = cxx_eval_outermost_constant_expr (tmp, true);
+ if (integer_zerop (tmp))
+ return potential_constant_expression_1 (TREE_OPERAND (t, 2),
+ want_rval, flags);
+ else if (TREE_CODE (tmp) == INTEGER_CST)
+ return potential_constant_expression_1 (TREE_OPERAND (t, 1),
+ want_rval, flags);
+ for (i = 1; i < 3; ++i)
+ if (potential_constant_expression_1 (TREE_OPERAND (t, i),
+ want_rval, tf_none))
+ return true;
+ if (flags & tf_error)
+ error ("expression %qE is not a constant-expression", t);
+ return false;
+
+ case VEC_INIT_EXPR:
+ if (VEC_INIT_EXPR_IS_CONSTEXPR (t))
+ return true;
+ if (flags & tf_error)
+ {
+ error ("non-constant array initialization");
+ diagnose_non_constexpr_vec_init (t);
+ }
+ return false;
+
+ default:
+ if (objc_is_property_ref (t))
+ return false;
+
+ sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t)));
+ gcc_unreachable();
+ return false;
+ }
+}
+
+/* The main entry point to the above. */
+
+bool
+potential_constant_expression (tree t)
+{
+ return potential_constant_expression_1 (t, false, tf_none);
+}
+
+/* As above, but require a constant rvalue. */
+
+bool
+potential_rvalue_constant_expression (tree t)
+{
+ return potential_constant_expression_1 (t, true, tf_none);
+}
+
+/* Like above, but complain about non-constant expressions. */
+
+bool
+require_potential_constant_expression (tree t)
+{
+ return potential_constant_expression_1 (t, false, tf_warning_or_error);
+}
+
+/* Cross product of the above. */
+
+bool
+require_potential_rvalue_constant_expression (tree t)
+{
+ return potential_constant_expression_1 (t, true, tf_warning_or_error);
+}
+
+#include "gt-cp-constexpr.h"
extern void finish_handler_parms (tree, tree);
extern void finish_handler (tree);
extern void finish_cleanup (tree, tree);
-extern bool literal_type_p (tree);
-extern tree register_constexpr_fundef (tree, tree);
-extern bool check_constexpr_ctor_body (tree, tree, bool);
-extern tree ensure_literal_type_for_constexpr_object (tree);
-extern bool potential_constant_expression (tree);
-extern bool potential_rvalue_constant_expression (tree);
-extern bool require_potential_constant_expression (tree);
-extern bool require_potential_rvalue_constant_expression (tree);
-extern tree cxx_constant_value (tree);
-extern tree maybe_constant_value (tree);
-extern tree maybe_constant_init (tree);
-extern bool is_sub_constant_expr (tree);
-extern bool reduced_constant_expression_p (tree);
-extern bool var_in_constexpr_fn (tree);
-extern void explain_invalid_constexpr_fn (tree);
-extern vec<tree> cx_error_context (void);
-extern bool is_this_parameter (tree);
+extern bool is_this_parameter (tree);
enum {
BCS_NO_SCOPE = 1,
extern tree expand_array_notation_exprs (tree);
bool cilkplus_an_triplet_types_ok_p (location_t, tree, tree, tree,
tree);
+
+/* In constexpr.c */
+extern bool literal_type_p (tree);
+extern tree register_constexpr_fundef (tree, tree);
+extern bool check_constexpr_ctor_body (tree, tree, bool);
+extern tree ensure_literal_type_for_constexpr_object (tree);
+extern bool potential_constant_expression (tree);
+extern bool potential_rvalue_constant_expression (tree);
+extern bool require_potential_constant_expression (tree);
+extern bool require_potential_rvalue_constant_expression (tree);
+extern tree cxx_constant_value (tree);
+extern tree maybe_constant_value (tree);
+extern tree maybe_constant_init (tree);
+extern bool is_sub_constant_expr (tree);
+extern bool reduced_constant_expression_p (tree);
+extern bool is_instantiation_of_constexpr (tree);
+extern bool var_in_constexpr_fn (tree);
+extern void explain_invalid_constexpr_fn (tree);
+extern vec<tree> cx_error_context (void);
+
/* In c-family/cilk.c */
extern bool cilk_valid_spawn (tree);
#include "builtins.h"
#include "convert.h"
-static bool verify_constant (tree, bool, bool *, bool *);
-#define VERIFY_CONSTANT(X) \
-do { \
- if (verify_constant ((X), allow_non_constant, non_constant_p, overflow_p)) \
- return t; \
- } while (0)
-
/* There routines provide a modular interface to perform many parsing
operations. They may therefore be used during actual parsing, or
during template instantiation, which may be regarded as a
}
}
-/* Returns true iff FUN is an instantiation of a constexpr function
- template or a defaulted constexpr function. */
-
-static inline bool
-is_instantiation_of_constexpr (tree fun)
-{
- return ((DECL_TEMPLOID_INSTANTIATION (fun)
- && DECL_DECLARED_CONSTEXPR_P (DECL_TI_TEMPLATE (fun)))
- || (DECL_DEFAULTED_FN (fun)
- && DECL_DECLARED_CONSTEXPR_P (fun)));
-
-}
-
/* Generate RTL for FN. */
bool
}
\f
-/* Return true if T is a literal type. */
+/* Return true if T designates the implied `this' parameter. */
bool
-literal_type_p (tree t)
-{
- if (SCALAR_TYPE_P (t)
- || TREE_CODE (t) == VECTOR_TYPE
- || TREE_CODE (t) == REFERENCE_TYPE)
- return true;
- if (CLASS_TYPE_P (t))
- {
- t = complete_type (t);
- gcc_assert (COMPLETE_TYPE_P (t) || errorcount);
- return CLASSTYPE_LITERAL_P (t);
- }
- if (TREE_CODE (t) == ARRAY_TYPE)
- return literal_type_p (strip_array_types (t));
- return false;
-}
-
-/* If DECL is a variable declared `constexpr', require its type
- be literal. Return the DECL if OK, otherwise NULL. */
-
-tree
-ensure_literal_type_for_constexpr_object (tree decl)
-{
- tree type = TREE_TYPE (decl);
- if (VAR_P (decl)
- && (DECL_DECLARED_CONSTEXPR_P (decl)
- || var_in_constexpr_fn (decl))
- && !processing_template_decl)
- {
- tree stype = strip_array_types (type);
- if (CLASS_TYPE_P (stype) && !COMPLETE_TYPE_P (complete_type (stype)))
- /* Don't complain here, we'll complain about incompleteness
- when we try to initialize the variable. */;
- else if (!literal_type_p (type))
- {
- if (DECL_DECLARED_CONSTEXPR_P (decl))
- error ("the type %qT of constexpr variable %qD is not literal",
- type, decl);
- else
- error ("variable %qD of non-literal type %qT in %<constexpr%> "
- "function", decl, type);
- explain_non_literal_class (type);
- return NULL;
- }
- }
- return decl;
-}
-
-/* Representation of entries in the constexpr function definition table. */
-
-struct GTY((for_user)) constexpr_fundef {
- tree decl;
- tree body;
-};
-
-struct constexpr_fundef_hasher : ggc_hasher<constexpr_fundef *>
-{
- static hashval_t hash (constexpr_fundef *);
- static bool equal (constexpr_fundef *, constexpr_fundef *);
-};
-
-/* This table holds all constexpr function definitions seen in
- the current translation unit. */
-
-static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table;
-
-/* Utility function used for managing the constexpr function table.
- Return true if the entries pointed to by P and Q are for the
- same constexpr function. */
-
-inline bool
-constexpr_fundef_hasher::equal (constexpr_fundef *lhs, constexpr_fundef *rhs)
-{
- return lhs->decl == rhs->decl;
-}
-
-/* Utility function used for managing the constexpr function table.
- Return a hash value for the entry pointed to by Q. */
-
-inline hashval_t
-constexpr_fundef_hasher::hash (constexpr_fundef *fundef)
-{
- return DECL_UID (fundef->decl);
-}
-
-/* Return a previously saved definition of function FUN. */
-
-static constexpr_fundef *
-retrieve_constexpr_fundef (tree fun)
-{
- constexpr_fundef fundef = { NULL, NULL };
- if (constexpr_fundef_table == NULL)
- return NULL;
-
- fundef.decl = fun;
- return constexpr_fundef_table->find (&fundef);
-}
-
-/* Check whether the parameter and return types of FUN are valid for a
- constexpr function, and complain if COMPLAIN. */
-
-static bool
-is_valid_constexpr_fn (tree fun, bool complain)
-{
- bool ret = true;
-
- if (DECL_INHERITED_CTOR_BASE (fun)
- && TREE_CODE (fun) == TEMPLATE_DECL)
- {
- ret = false;
- if (complain)
- error ("inherited constructor %qD is not constexpr",
- get_inherited_ctor (fun));
- }
- else
- {
- for (tree parm = FUNCTION_FIRST_USER_PARM (fun);
- parm != NULL_TREE; parm = TREE_CHAIN (parm))
- if (!literal_type_p (TREE_TYPE (parm)))
- {
- ret = false;
- if (complain)
- {
- error ("invalid type for parameter %d of constexpr "
- "function %q+#D", DECL_PARM_INDEX (parm), fun);
- explain_non_literal_class (TREE_TYPE (parm));
- }
- }
- }
-
- if (!DECL_CONSTRUCTOR_P (fun))
- {
- tree rettype = TREE_TYPE (TREE_TYPE (fun));
- if (!literal_type_p (rettype))
- {
- ret = false;
- if (complain)
- {
- error ("invalid return type %qT of constexpr function %q+D",
- rettype, fun);
- explain_non_literal_class (rettype);
- }
- }
-
- if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun)
- && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun)))
- {
- ret = false;
- if (complain)
- {
- error ("enclosing class of constexpr non-static member "
- "function %q+#D is not a literal type", fun);
- explain_non_literal_class (DECL_CONTEXT (fun));
- }
- }
- }
- else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun)))
- {
- ret = false;
- if (complain)
- error ("%q#T has virtual base classes", DECL_CONTEXT (fun));
- }
-
- return ret;
-}
-
-/* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF
- for a member of an anonymous aggregate, INIT is the initializer for that
- member, and VEC_OUTER is the vector of constructor elements for the class
- whose constructor we are processing. Add the initializer to the vector
- and return true to indicate success. */
-
-static bool
-build_anon_member_initialization (tree member, tree init,
- vec<constructor_elt, va_gc> **vec_outer)
-{
- /* MEMBER presents the relevant fields from the inside out, but we need
- to build up the initializer from the outside in so that we can reuse
- previously built CONSTRUCTORs if this is, say, the second field in an
- anonymous struct. So we use a vec as a stack. */
- auto_vec<tree, 2> fields;
- do
- {
- fields.safe_push (TREE_OPERAND (member, 1));
- member = TREE_OPERAND (member, 0);
- }
- while (ANON_AGGR_TYPE_P (TREE_TYPE (member))
- && TREE_CODE (member) == COMPONENT_REF);
-
- /* VEC has the constructor elements vector for the context of FIELD.
- If FIELD is an anonymous aggregate, we will push inside it. */
- vec<constructor_elt, va_gc> **vec = vec_outer;
- tree field;
- while (field = fields.pop(),
- ANON_AGGR_TYPE_P (TREE_TYPE (field)))
- {
- tree ctor;
- /* If there is already an outer constructor entry for the anonymous
- aggregate FIELD, use it; otherwise, insert one. */
- if (vec_safe_is_empty (*vec)
- || (*vec)->last().index != field)
- {
- ctor = build_constructor (TREE_TYPE (field), NULL);
- CONSTRUCTOR_APPEND_ELT (*vec, field, ctor);
- }
- else
- ctor = (*vec)->last().value;
- vec = &CONSTRUCTOR_ELTS (ctor);
- }
-
- /* Now we're at the innermost field, the one that isn't an anonymous
- aggregate. Add its initializer to the CONSTRUCTOR and we're done. */
- gcc_assert (fields.is_empty());
- CONSTRUCTOR_APPEND_ELT (*vec, field, init);
-
- return true;
-}
-
-/* Subroutine of build_constexpr_constructor_member_initializers.
- The expression tree T represents a data member initialization
- in a (constexpr) constructor definition. Build a pairing of
- the data member with its initializer, and prepend that pair
- to the existing initialization pair INITS. */
-
-static bool
-build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec)
+is_this_parameter (tree t)
{
- tree member, init;
- if (TREE_CODE (t) == CLEANUP_POINT_EXPR)
- t = TREE_OPERAND (t, 0);
- if (TREE_CODE (t) == EXPR_STMT)
- t = TREE_OPERAND (t, 0);
- if (t == error_mark_node)
+ if (!DECL_P (t) || DECL_NAME (t) != this_identifier)
return false;
- if (TREE_CODE (t) == STATEMENT_LIST)
- {
- tree_stmt_iterator i;
- for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
- {
- if (! build_data_member_initialization (tsi_stmt (i), vec))
- return false;
- }
- return true;
- }
- if (TREE_CODE (t) == CLEANUP_STMT)
- {
- /* We can't see a CLEANUP_STMT in a constructor for a literal class,
- but we can in a constexpr constructor for a non-literal class. Just
- ignore it; either all the initialization will be constant, in which
- case the cleanup can't run, or it can't be constexpr.
- Still recurse into CLEANUP_BODY. */
- return build_data_member_initialization (CLEANUP_BODY (t), vec);
- }
- if (TREE_CODE (t) == CONVERT_EXPR)
- t = TREE_OPERAND (t, 0);
- if (TREE_CODE (t) == INIT_EXPR
- || TREE_CODE (t) == MODIFY_EXPR)
- {
- member = TREE_OPERAND (t, 0);
- init = break_out_target_exprs (TREE_OPERAND (t, 1));
- }
- else if (TREE_CODE (t) == CALL_EXPR)
- {
- member = CALL_EXPR_ARG (t, 0);
- /* We don't use build_cplus_new here because it complains about
- abstract bases. Leaving the call unwrapped means that it has the
- wrong type, but cxx_eval_constant_expression doesn't care. */
- init = break_out_target_exprs (t);
- }
- else if (TREE_CODE (t) == BIND_EXPR)
- return build_data_member_initialization (BIND_EXPR_BODY (t), vec);
- else if (TREE_CODE (t) == DECL_EXPR
- || TREE_CODE (t) == USING_STMT)
- /* Declaring a temporary, don't add it to the CONSTRUCTOR.
- Likewise for using directives. */
- return true;
- else
- gcc_unreachable ();
- if (INDIRECT_REF_P (member))
- member = TREE_OPERAND (member, 0);
- if (TREE_CODE (member) == NOP_EXPR)
- {
- tree op = member;
- STRIP_NOPS (op);
- if (TREE_CODE (op) == ADDR_EXPR)
- {
- gcc_assert (same_type_ignoring_top_level_qualifiers_p
- (TREE_TYPE (TREE_TYPE (op)),
- TREE_TYPE (TREE_TYPE (member))));
- /* Initializing a cv-qualified member; we need to look through
- the const_cast. */
- member = op;
- }
- else if (op == current_class_ptr
- && (same_type_ignoring_top_level_qualifiers_p
- (TREE_TYPE (TREE_TYPE (member)),
- current_class_type)))
- /* Delegating constructor. */
- member = op;
- else
- {
- /* This is an initializer for an empty base; keep it for now so
- we can check it in cxx_eval_bare_aggregate. */
- gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member))));
- }
- }
- if (TREE_CODE (member) == ADDR_EXPR)
- member = TREE_OPERAND (member, 0);
- if (TREE_CODE (member) == COMPONENT_REF)
- {
- tree aggr = TREE_OPERAND (member, 0);
- if (TREE_CODE (aggr) != COMPONENT_REF)
- /* Normal member initialization. */
- member = TREE_OPERAND (member, 1);
- else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr)))
- /* Initializing a member of an anonymous union. */
- return build_anon_member_initialization (member, init, vec);
- else
- /* We're initializing a vtable pointer in a base. Leave it as
- COMPONENT_REF so we remember the path to get to the vfield. */
- gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node);
- }
-
- CONSTRUCTOR_APPEND_ELT (*vec, member, init);
- return true;
-}
-
-/* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval.
- In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a
- BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */
-
-static bool
-check_constexpr_bind_expr_vars (tree t)
-{
- gcc_assert (TREE_CODE (t) == BIND_EXPR);
-
- if (cxx_dialect >= cxx14)
- return true;
-
- for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var))
- if (TREE_CODE (var) == TYPE_DECL
- && DECL_IMPLICIT_TYPEDEF_P (var))
- return false;
+ gcc_assert (TREE_CODE (t) == PARM_DECL || is_capture_proxy (t));
return true;
}
-/* Subroutine of check_constexpr_ctor_body. */
-
-static bool
-check_constexpr_ctor_body_1 (tree last, tree list)
-{
- switch (TREE_CODE (list))
- {
- case DECL_EXPR:
- if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL)
- return true;
- if (cxx_dialect >= cxx14)
- return true;
- return false;
-
- case CLEANUP_POINT_EXPR:
- return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0),
- /*complain=*/false);
-
- case BIND_EXPR:
- if (!check_constexpr_bind_expr_vars (list)
- || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list),
- /*complain=*/false))
- return false;
- return true;
-
- case USING_STMT:
- case STATIC_ASSERT:
- return true;
-
- default:
- return false;
- }
-}
-
-/* Make sure that there are no statements after LAST in the constructor
- body represented by LIST. */
-
-bool
-check_constexpr_ctor_body (tree last, tree list, bool complain)
-{
- bool ok = true;
- if (TREE_CODE (list) == STATEMENT_LIST)
- {
- tree_stmt_iterator i = tsi_last (list);
- for (; !tsi_end_p (i); tsi_prev (&i))
- {
- tree t = tsi_stmt (i);
- if (t == last)
- break;
- if (!check_constexpr_ctor_body_1 (last, t))
- {
- ok = false;
- break;
- }
- }
- }
- else if (list != last
- && !check_constexpr_ctor_body_1 (last, list))
- ok = false;
- if (!ok)
- {
- if (complain)
- error ("constexpr constructor does not have empty body");
- DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false;
- }
- return ok;
-}
-
-/* V is a vector of constructor elements built up for the base and member
- initializers of a constructor for TYPE. They need to be in increasing
- offset order, which they might not be yet if TYPE has a primary base
- which is not first in the base-clause or a vptr and at least one base
- all of which are non-primary. */
-
-static vec<constructor_elt, va_gc> *
-sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v)
-{
- tree pri = CLASSTYPE_PRIMARY_BINFO (type);
- tree field_type;
- unsigned i;
- constructor_elt *ce;
-
- if (pri)
- field_type = BINFO_TYPE (pri);
- else if (TYPE_CONTAINS_VPTR_P (type))
- field_type = vtbl_ptr_type_node;
- else
- return v;
-
- /* Find the element for the primary base or vptr and move it to the
- beginning of the vec. */
- for (i = 0; vec_safe_iterate (v, i, &ce); ++i)
- if (TREE_TYPE (ce->index) == field_type)
- break;
-
- if (i > 0 && i < vec_safe_length (v))
- {
- vec<constructor_elt, va_gc> &vref = *v;
- constructor_elt elt = vref[i];
- for (; i > 0; --i)
- vref[i] = vref[i-1];
- vref[0] = elt;
- }
-
- return v;
-}
-
-/* Build compile-time evalable representations of member-initializer list
- for a constexpr constructor. */
-
-static tree
-build_constexpr_constructor_member_initializers (tree type, tree body)
-{
- vec<constructor_elt, va_gc> *vec = NULL;
- bool ok = true;
- if (TREE_CODE (body) == MUST_NOT_THROW_EXPR
- || TREE_CODE (body) == EH_SPEC_BLOCK)
- body = TREE_OPERAND (body, 0);
- if (TREE_CODE (body) == STATEMENT_LIST)
- body = STATEMENT_LIST_HEAD (body)->stmt;
- body = BIND_EXPR_BODY (body);
- if (TREE_CODE (body) == CLEANUP_POINT_EXPR)
- {
- body = TREE_OPERAND (body, 0);
- if (TREE_CODE (body) == EXPR_STMT)
- body = TREE_OPERAND (body, 0);
- if (TREE_CODE (body) == INIT_EXPR
- && (same_type_ignoring_top_level_qualifiers_p
- (TREE_TYPE (TREE_OPERAND (body, 0)),
- current_class_type)))
- {
- /* Trivial copy. */
- return TREE_OPERAND (body, 1);
- }
- ok = build_data_member_initialization (body, &vec);
- }
- else if (TREE_CODE (body) == STATEMENT_LIST)
- {
- tree_stmt_iterator i;
- for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i))
- {
- ok = build_data_member_initialization (tsi_stmt (i), &vec);
- if (!ok)
- break;
- }
- }
- else if (TREE_CODE (body) == TRY_BLOCK)
- {
- error ("body of %<constexpr%> constructor cannot be "
- "a function-try-block");
- return error_mark_node;
- }
- else if (EXPR_P (body))
- ok = build_data_member_initialization (body, &vec);
- else
- gcc_assert (errorcount > 0);
- if (ok)
- {
- if (vec_safe_length (vec) > 0)
- {
- /* In a delegating constructor, return the target. */
- constructor_elt *ce = &(*vec)[0];
- if (ce->index == current_class_ptr)
- {
- body = ce->value;
- vec_free (vec);
- return body;
- }
- }
- vec = sort_constexpr_mem_initializers (type, vec);
- return build_constructor (type, vec);
- }
- else
- return error_mark_node;
-}
-
-/* Subroutine of register_constexpr_fundef. BODY is the body of a function
- declared to be constexpr, or a sub-statement thereof. Returns the
- return value if suitable, error_mark_node for a statement not allowed in
- a constexpr function, or NULL_TREE if no return value was found. */
-
-static tree
-constexpr_fn_retval (tree body)
-{
- switch (TREE_CODE (body))
- {
- case STATEMENT_LIST:
- {
- tree_stmt_iterator i;
- tree expr = NULL_TREE;
- for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i))
- {
- tree s = constexpr_fn_retval (tsi_stmt (i));
- if (s == error_mark_node)
- return error_mark_node;
- else if (s == NULL_TREE)
- /* Keep iterating. */;
- else if (expr)
- /* Multiple return statements. */
- return error_mark_node;
- else
- expr = s;
- }
- return expr;
- }
-
- case RETURN_EXPR:
- return break_out_target_exprs (TREE_OPERAND (body, 0));
-
- case DECL_EXPR:
- if (TREE_CODE (DECL_EXPR_DECL (body)) == USING_DECL)
- return NULL_TREE;
- if (cxx_dialect >= cxx14)
- return NULL_TREE;
- return error_mark_node;
-
- case CLEANUP_POINT_EXPR:
- return constexpr_fn_retval (TREE_OPERAND (body, 0));
-
- case BIND_EXPR:
- if (!check_constexpr_bind_expr_vars (body))
- return error_mark_node;
- return constexpr_fn_retval (BIND_EXPR_BODY (body));
-
- case USING_STMT:
- return NULL_TREE;
-
- default:
- return error_mark_node;
- }
-}
-
-/* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of
- FUN; do the necessary transformations to turn it into a single expression
- that we can store in the hash table. */
-
-static tree
-massage_constexpr_body (tree fun, tree body)
-{
- if (DECL_CONSTRUCTOR_P (fun))
- body = build_constexpr_constructor_member_initializers
- (DECL_CONTEXT (fun), body);
- else
- {
- if (TREE_CODE (body) == EH_SPEC_BLOCK)
- body = EH_SPEC_STMTS (body);
- if (TREE_CODE (body) == MUST_NOT_THROW_EXPR)
- body = TREE_OPERAND (body, 0);
- body = constexpr_fn_retval (body);
- }
- return body;
-}
-
-/* FUN is a constexpr constructor with massaged body BODY. Return true
- if some bases/fields are uninitialized, and complain if COMPLAIN. */
-
-static bool
-cx_check_missing_mem_inits (tree fun, tree body, bool complain)
-{
- bool bad;
- tree field;
- unsigned i, nelts;
- tree ctype;
-
- if (TREE_CODE (body) != CONSTRUCTOR)
- return false;
-
- nelts = CONSTRUCTOR_NELTS (body);
- ctype = DECL_CONTEXT (fun);
- field = TYPE_FIELDS (ctype);
-
- if (TREE_CODE (ctype) == UNION_TYPE)
- {
- if (nelts == 0 && next_initializable_field (field))
- {
- if (complain)
- error ("%<constexpr%> constructor for union %qT must "
- "initialize exactly one non-static data member", ctype);
- return true;
- }
- return false;
- }
-
- bad = false;
- for (i = 0; i <= nelts; ++i)
- {
- tree index;
- if (i == nelts)
- index = NULL_TREE;
- else
- {
- index = CONSTRUCTOR_ELT (body, i)->index;
- /* Skip base and vtable inits. */
- if (TREE_CODE (index) != FIELD_DECL
- || DECL_ARTIFICIAL (index))
- continue;
- }
- for (; field != index; field = DECL_CHAIN (field))
- {
- tree ftype;
- if (TREE_CODE (field) != FIELD_DECL
- || (DECL_C_BIT_FIELD (field) && !DECL_NAME (field))
- || DECL_ARTIFICIAL (field))
- continue;
- ftype = strip_array_types (TREE_TYPE (field));
- if (type_has_constexpr_default_constructor (ftype))
- {
- /* It's OK to skip a member with a trivial constexpr ctor.
- A constexpr ctor that isn't trivial should have been
- added in by now. */
- gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype)
- || errorcount != 0);
- continue;
- }
- if (!complain)
- return true;
- error ("uninitialized member %qD in %<constexpr%> constructor",
- field);
- bad = true;
- }
- if (field == NULL_TREE)
- break;
- field = DECL_CHAIN (field);
- }
-
- return bad;
-}
-
-/* We are processing the definition of the constexpr function FUN.
- Check that its BODY fulfills the propriate requirements and
- enter it in the constexpr function definition table.
- For constructor BODY is actually the TREE_LIST of the
- member-initializer list. */
-
-tree
-register_constexpr_fundef (tree fun, tree body)
-{
- constexpr_fundef entry;
- constexpr_fundef **slot;
-
- if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun)))
- return NULL;
-
- body = massage_constexpr_body (fun, body);
- if (body == NULL_TREE || body == error_mark_node)
- {
- if (!DECL_CONSTRUCTOR_P (fun))
- error ("body of constexpr function %qD not a return-statement", fun);
- return NULL;
- }
-
- if (!potential_rvalue_constant_expression (body))
- {
- if (!DECL_GENERATED_P (fun))
- require_potential_rvalue_constant_expression (body);
- return NULL;
- }
-
- if (DECL_CONSTRUCTOR_P (fun)
- && cx_check_missing_mem_inits (fun, body, !DECL_GENERATED_P (fun)))
- return NULL;
-
- /* Create the constexpr function table if necessary. */
- if (constexpr_fundef_table == NULL)
- constexpr_fundef_table
- = hash_table<constexpr_fundef_hasher>::create_ggc (101);
-
- entry.decl = fun;
- entry.body = body;
- slot = constexpr_fundef_table->find_slot (&entry, INSERT);
-
- gcc_assert (*slot == NULL);
- *slot = ggc_alloc<constexpr_fundef> ();
- **slot = entry;
-
- return fun;
-}
-
-/* FUN is a non-constexpr function called in a context that requires a
- constant expression. If it comes from a constexpr template, explain why
- the instantiation isn't constexpr. */
-
-void
-explain_invalid_constexpr_fn (tree fun)
-{
- static hash_set<tree> *diagnosed;
- tree body;
- location_t save_loc;
- /* Only diagnose defaulted functions or instantiations. */
- if (!DECL_DEFAULTED_FN (fun)
- && !is_instantiation_of_constexpr (fun))
- return;
- if (diagnosed == NULL)
- diagnosed = new hash_set<tree>;
- if (diagnosed->add (fun))
- /* Already explained. */
- return;
-
- save_loc = input_location;
- input_location = DECL_SOURCE_LOCATION (fun);
- inform (0, "%q+D is not usable as a constexpr function because:", fun);
- /* First check the declaration. */
- if (is_valid_constexpr_fn (fun, true))
- {
- /* Then if it's OK, the body. */
- if (!DECL_DECLARED_CONSTEXPR_P (fun))
- explain_implicit_non_constexpr (fun);
- else
- {
- body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun));
- require_potential_rvalue_constant_expression (body);
- if (DECL_CONSTRUCTOR_P (fun))
- cx_check_missing_mem_inits (fun, body, true);
- }
- }
- input_location = save_loc;
-}
-
-/* Objects of this type represent calls to constexpr functions
- along with the bindings of parameters to their arguments, for
- the purpose of compile time evaluation. */
-
-struct GTY((for_user)) constexpr_call {
- /* Description of the constexpr function definition. */
- constexpr_fundef *fundef;
- /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE
- is a parameter _DECL and the TREE_VALUE is the value of the parameter.
- Note: This arrangement is made to accommodate the use of
- iterative_hash_template_arg (see pt.c). If you change this
- representation, also change the hash calculation in
- cxx_eval_call_expression. */
- tree bindings;
- /* Result of the call.
- NULL means the call is being evaluated.
- error_mark_node means that the evaluation was erroneous;
- otherwise, the actuall value of the call. */
- tree result;
- /* The hash of this call; we remember it here to avoid having to
- recalculate it when expanding the hash table. */
- hashval_t hash;
-};
-
-struct constexpr_call_hasher : ggc_hasher<constexpr_call *>
-{
- static hashval_t hash (constexpr_call *);
- static bool equal (constexpr_call *, constexpr_call *);
- };
-
-/* A table of all constexpr calls that have been evaluated by the
- compiler in this translation unit. */
-
-static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table;
-
-static tree cxx_eval_constant_expression (const constexpr_call *, tree,
- bool, bool, bool *, bool *);
-
-/* Compute a hash value for a constexpr call representation. */
-
-inline hashval_t
-constexpr_call_hasher::hash (constexpr_call *info)
-{
- return info->hash;
-}
-
-/* Return true if the objects pointed to by P and Q represent calls
- to the same constexpr function with the same arguments.
- Otherwise, return false. */
-
-bool
-constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs)
-{
- tree lhs_bindings;
- tree rhs_bindings;
- if (lhs == rhs)
- return 1;
- if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef))
- return 0;
- lhs_bindings = lhs->bindings;
- rhs_bindings = rhs->bindings;
- while (lhs_bindings != NULL && rhs_bindings != NULL)
- {
- tree lhs_arg = TREE_VALUE (lhs_bindings);
- tree rhs_arg = TREE_VALUE (rhs_bindings);
- gcc_assert (TREE_TYPE (lhs_arg) == TREE_TYPE (rhs_arg));
- if (!cp_tree_equal (lhs_arg, rhs_arg))
- return 0;
- lhs_bindings = TREE_CHAIN (lhs_bindings);
- rhs_bindings = TREE_CHAIN (rhs_bindings);
- }
- return lhs_bindings == rhs_bindings;
-}
-
-/* Initialize the constexpr call table, if needed. */
-
-static void
-maybe_initialize_constexpr_call_table (void)
-{
- if (constexpr_call_table == NULL)
- constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101);
-}
-
-/* Return true if T designates the implied `this' parameter. */
-
-bool
-is_this_parameter (tree t)
-{
- if (!DECL_P (t) || DECL_NAME (t) != this_identifier)
- return false;
- gcc_assert (TREE_CODE (t) == PARM_DECL || is_capture_proxy (t));
- return true;
-}
-
-/* We have an expression tree T that represents a call, either CALL_EXPR
- or AGGR_INIT_EXPR. If the call is lexically to a named function,
- retrun the _DECL for that function. */
-
-static tree
-get_function_named_in_call (tree t)
-{
- tree fun = NULL;
- switch (TREE_CODE (t))
- {
- case CALL_EXPR:
- fun = CALL_EXPR_FN (t);
- break;
-
- case AGGR_INIT_EXPR:
- fun = AGGR_INIT_EXPR_FN (t);
- break;
-
- default:
- gcc_unreachable();
- break;
- }
- if (TREE_CODE (fun) == ADDR_EXPR
- && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL)
- fun = TREE_OPERAND (fun, 0);
- return fun;
-}
-
-/* We have an expression tree T that represents a call, either CALL_EXPR
- or AGGR_INIT_EXPR. Return the Nth argument. */
-
-static inline tree
-get_nth_callarg (tree t, int n)
-{
- switch (TREE_CODE (t))
- {
- case CALL_EXPR:
- return CALL_EXPR_ARG (t, n);
-
- case AGGR_INIT_EXPR:
- return AGGR_INIT_EXPR_ARG (t, n);
-
- default:
- gcc_unreachable ();
- return NULL;
- }
-}
-
-/* Look up the binding of the function parameter T in a constexpr
- function call context CALL. */
-
-static tree
-lookup_parameter_binding (const constexpr_call *call, tree t)
-{
- tree b = purpose_member (t, call->bindings);
- return TREE_VALUE (b);
-}
-
-/* Attempt to evaluate T which represents a call to a builtin function.
- We assume here that all builtin functions evaluate to scalar types
- represented by _CST nodes. */
-
-static tree
-cxx_eval_builtin_function_call (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- const int nargs = call_expr_nargs (t);
- tree *args = (tree *) alloca (nargs * sizeof (tree));
- tree new_call;
- int i;
- for (i = 0; i < nargs; ++i)
- {
- args[i] = cxx_eval_constant_expression (call, CALL_EXPR_ARG (t, i),
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- if (allow_non_constant && *non_constant_p)
- return t;
- }
- if (*non_constant_p)
- return t;
- new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t),
- CALL_EXPR_FN (t), nargs, args);
- new_call = fold (new_call);
- VERIFY_CONSTANT (new_call);
- return new_call;
-}
-
-/* TEMP is the constant value of a temporary object of type TYPE. Adjust
- the type of the value to match. */
-
-static tree
-adjust_temp_type (tree type, tree temp)
-{
- if (TREE_TYPE (temp) == type)
- return temp;
- /* Avoid wrapping an aggregate value in a NOP_EXPR. */
- if (TREE_CODE (temp) == CONSTRUCTOR)
- return build_constructor (type, CONSTRUCTOR_ELTS (temp));
- gcc_assert (scalarish_type_p (type));
- return cp_fold_convert (type, temp);
-}
-
-/* Subroutine of cxx_eval_call_expression.
- We are processing a call expression (either CALL_EXPR or
- AGGR_INIT_EXPR) in the call context of OLD_CALL. Evaluate
- all arguments and bind their values to correspondings
- parameters, making up the NEW_CALL context. */
-
-static void
-cxx_bind_parameters_in_call (const constexpr_call *old_call, tree t,
- constexpr_call *new_call,
- bool allow_non_constant,
- bool *non_constant_p, bool *overflow_p)
-{
- const int nargs = call_expr_nargs (t);
- tree fun = new_call->fundef->decl;
- tree parms = DECL_ARGUMENTS (fun);
- int i;
- for (i = 0; i < nargs; ++i)
- {
- tree x, arg;
- tree type = parms ? TREE_TYPE (parms) : void_type_node;
- /* For member function, the first argument is a pointer to the implied
- object. And for an object construction, don't bind `this' before
- it is fully constructed. */
- if (i == 0 && DECL_CONSTRUCTOR_P (fun))
- goto next;
- x = get_nth_callarg (t, i);
- if (parms && DECL_BY_REFERENCE (parms))
- {
- /* cp_genericize made this a reference for argument passing, but
- we don't want to treat it like one for constexpr evaluation. */
- gcc_assert (TREE_CODE (type) == REFERENCE_TYPE);
- gcc_assert (TREE_CODE (TREE_TYPE (x)) == REFERENCE_TYPE);
- type = TREE_TYPE (type);
- x = convert_from_reference (x);
- }
- arg = cxx_eval_constant_expression (old_call, x, allow_non_constant,
- TREE_CODE (type) == REFERENCE_TYPE,
- non_constant_p, overflow_p);
- /* Don't VERIFY_CONSTANT here. */
- if (*non_constant_p && allow_non_constant)
- return;
- /* Just discard ellipsis args after checking their constantitude. */
- if (!parms)
- continue;
- if (*non_constant_p)
- /* Don't try to adjust the type of non-constant args. */
- goto next;
-
- /* Make sure the binding has the same type as the parm. */
- if (TREE_CODE (type) != REFERENCE_TYPE)
- arg = adjust_temp_type (type, arg);
- new_call->bindings = tree_cons (parms, arg, new_call->bindings);
- next:
- parms = TREE_CHAIN (parms);
- }
-}
-
-/* Variables and functions to manage constexpr call expansion context.
- These do not need to be marked for PCH or GC. */
-
-/* FIXME remember and print actual constant arguments. */
-static vec<tree> call_stack = vNULL;
-static int call_stack_tick;
-static int last_cx_error_tick;
-
-static bool
-push_cx_call_context (tree call)
-{
- ++call_stack_tick;
- if (!EXPR_HAS_LOCATION (call))
- SET_EXPR_LOCATION (call, input_location);
- call_stack.safe_push (call);
- if (call_stack.length () > (unsigned) max_constexpr_depth)
- return false;
- return true;
-}
-
-static void
-pop_cx_call_context (void)
-{
- ++call_stack_tick;
- call_stack.pop ();
-}
-
-vec<tree>
-cx_error_context (void)
-{
- vec<tree> r = vNULL;
- if (call_stack_tick != last_cx_error_tick
- && !call_stack.is_empty ())
- r = call_stack;
- last_cx_error_tick = call_stack_tick;
- return r;
-}
-
-/* Subroutine of cxx_eval_constant_expression.
- Evaluate the call expression tree T in the context of OLD_CALL expression
- evaluation. */
-
-static tree
-cxx_eval_call_expression (const constexpr_call *old_call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- location_t loc = EXPR_LOC_OR_LOC (t, input_location);
- tree fun = get_function_named_in_call (t);
- tree result;
- constexpr_call new_call = { NULL, NULL, NULL, 0 };
- constexpr_call **slot;
- constexpr_call *entry;
- bool depth_ok;
-
- if (TREE_CODE (fun) != FUNCTION_DECL)
- {
- /* Might be a constexpr function pointer. */
- fun = cxx_eval_constant_expression (old_call, fun, allow_non_constant,
- /*addr*/false, non_constant_p,
- overflow_p);
- STRIP_NOPS (fun);
- if (TREE_CODE (fun) == ADDR_EXPR)
- fun = TREE_OPERAND (fun, 0);
- }
- if (TREE_CODE (fun) != FUNCTION_DECL)
- {
- if (!allow_non_constant && !*non_constant_p)
- error_at (loc, "expression %qE does not designate a constexpr "
- "function", fun);
- *non_constant_p = true;
- return t;
- }
- if (DECL_CLONED_FUNCTION_P (fun))
- fun = DECL_CLONED_FUNCTION (fun);
- if (is_builtin_fn (fun))
- return cxx_eval_builtin_function_call (old_call, t, allow_non_constant,
- addr, non_constant_p, overflow_p);
- if (!DECL_DECLARED_CONSTEXPR_P (fun))
- {
- if (!allow_non_constant)
- {
- error_at (loc, "call to non-constexpr function %qD", fun);
- explain_invalid_constexpr_fn (fun);
- }
- *non_constant_p = true;
- return t;
- }
-
- /* Shortcut trivial constructor/op=. */
- if (trivial_fn_p (fun))
- {
- if (call_expr_nargs (t) == 2)
- {
- tree arg = convert_from_reference (get_nth_callarg (t, 1));
- return cxx_eval_constant_expression (old_call, arg, allow_non_constant,
- addr, non_constant_p, overflow_p);
- }
- else if (TREE_CODE (t) == AGGR_INIT_EXPR
- && AGGR_INIT_ZERO_FIRST (t))
- return build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false);
- }
-
- /* If in direct recursive call, optimize definition search. */
- if (old_call != NULL && old_call->fundef->decl == fun)
- new_call.fundef = old_call->fundef;
- else
- {
- new_call.fundef = retrieve_constexpr_fundef (fun);
- if (new_call.fundef == NULL || new_call.fundef->body == NULL)
- {
- if (!allow_non_constant)
- {
- if (DECL_INITIAL (fun))
- {
- /* The definition of fun was somehow unsuitable. */
- error_at (loc, "%qD called in a constant expression", fun);
- explain_invalid_constexpr_fn (fun);
- }
- else
- error_at (loc, "%qD used before its definition", fun);
- }
- *non_constant_p = true;
- return t;
- }
- }
- cxx_bind_parameters_in_call (old_call, t, &new_call,
- allow_non_constant, non_constant_p, overflow_p);
- if (*non_constant_p)
- return t;
-
- depth_ok = push_cx_call_context (t);
-
- new_call.hash
- = iterative_hash_template_arg (new_call.bindings,
- constexpr_fundef_hasher::hash (new_call.fundef));
-
- /* If we have seen this call before, we are done. */
- maybe_initialize_constexpr_call_table ();
- slot = constexpr_call_table->find_slot (&new_call, INSERT);
- entry = *slot;
- if (entry == NULL)
- {
- /* We need to keep a pointer to the entry, not just the slot, as the
- slot can move in the call to cxx_eval_builtin_function_call. */
- *slot = entry = ggc_alloc<constexpr_call> ();
- *entry = new_call;
- }
- /* Calls which are in progress have their result set to NULL
- so that we can detect circular dependencies. */
- else if (entry->result == NULL)
- {
- if (!allow_non_constant)
- error ("call has circular dependency");
- *non_constant_p = true;
- entry->result = result = error_mark_node;
- }
-
- if (!depth_ok)
- {
- if (!allow_non_constant)
- error ("constexpr evaluation depth exceeds maximum of %d (use "
- "-fconstexpr-depth= to increase the maximum)",
- max_constexpr_depth);
- *non_constant_p = true;
- entry->result = result = error_mark_node;
- }
- else
- {
- result = entry->result;
- if (!result || result == error_mark_node)
- result = (cxx_eval_constant_expression
- (&new_call, new_call.fundef->body,
- allow_non_constant, addr,
- non_constant_p, overflow_p));
- if (result == error_mark_node)
- *non_constant_p = true;
- if (*non_constant_p)
- entry->result = result = error_mark_node;
- else
- {
- /* If this was a call to initialize an object, set the type of
- the CONSTRUCTOR to the type of that object. */
- if (DECL_CONSTRUCTOR_P (fun))
- {
- tree ob_arg = get_nth_callarg (t, 0);
- STRIP_NOPS (ob_arg);
- gcc_assert (TYPE_PTR_P (TREE_TYPE (ob_arg))
- && CLASS_TYPE_P (TREE_TYPE (TREE_TYPE (ob_arg))));
- result = adjust_temp_type (TREE_TYPE (TREE_TYPE (ob_arg)),
- result);
- }
- entry->result = result;
- }
- }
-
- pop_cx_call_context ();
- return unshare_expr (result);
-}
-
-/* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */
-
-bool
-reduced_constant_expression_p (tree t)
-{
- switch (TREE_CODE (t))
- {
- case PTRMEM_CST:
- /* Even if we can't lower this yet, it's constant. */
- return true;
-
- case CONSTRUCTOR:
- /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */
- tree elt; unsigned HOST_WIDE_INT idx;
- FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), idx, elt)
- if (!reduced_constant_expression_p (elt))
- return false;
- return true;
-
- default:
- /* FIXME are we calling this too much? */
- return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE;
- }
-}
-
-/* Some expressions may have constant operands but are not constant
- themselves, such as 1/0. Call this function (or rather, the macro
- following it) to check for that condition.
-
- We only call this in places that require an arithmetic constant, not in
- places where we might have a non-constant expression that can be a
- component of a constant expression, such as the address of a constexpr
- variable that might be dereferenced later. */
-
-static bool
-verify_constant (tree t, bool allow_non_constant, bool *non_constant_p,
- bool *overflow_p)
-{
- if (!*non_constant_p && !reduced_constant_expression_p (t))
- {
- if (!allow_non_constant)
- error ("%q+E is not a constant expression", t);
- *non_constant_p = true;
- }
- if (TREE_OVERFLOW_P (t))
- {
- if (!allow_non_constant)
- {
- permerror (input_location, "overflow in constant expression");
- /* If we're being permissive (and are in an enforcing
- context), ignore the overflow. */
- if (flag_permissive)
- return *non_constant_p;
- }
- *overflow_p = true;
- }
- return *non_constant_p;
-}
-
-/* Subroutine of cxx_eval_constant_expression.
- Attempt to reduce the unary expression tree T to a compile time value.
- If successful, return the value. Otherwise issue a diagnostic
- and return error_mark_node. */
-
-static tree
-cxx_eval_unary_expression (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- tree r;
- tree orig_arg = TREE_OPERAND (t, 0);
- tree arg = cxx_eval_constant_expression (call, orig_arg, allow_non_constant,
- addr, non_constant_p, overflow_p);
- VERIFY_CONSTANT (arg);
- if (arg == orig_arg)
- return t;
- r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), arg);
- VERIFY_CONSTANT (r);
- return r;
-}
-
-/* Subroutine of cxx_eval_constant_expression.
- Like cxx_eval_unary_expression, except for binary expressions. */
-
-static tree
-cxx_eval_binary_expression (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- tree r;
- tree orig_lhs = TREE_OPERAND (t, 0);
- tree orig_rhs = TREE_OPERAND (t, 1);
- tree lhs, rhs;
- lhs = cxx_eval_constant_expression (call, orig_lhs,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- VERIFY_CONSTANT (lhs);
- rhs = cxx_eval_constant_expression (call, orig_rhs,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- VERIFY_CONSTANT (rhs);
- if (lhs == orig_lhs && rhs == orig_rhs)
- return t;
- r = fold_build2 (TREE_CODE (t), TREE_TYPE (t), lhs, rhs);
- VERIFY_CONSTANT (r);
- return r;
-}
-
-/* Subroutine of cxx_eval_constant_expression.
- Attempt to evaluate condition expressions. Dead branches are not
- looked into. */
-
-static tree
-cxx_eval_conditional_expression (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- tree val = cxx_eval_constant_expression (call, TREE_OPERAND (t, 0),
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- VERIFY_CONSTANT (val);
- /* Don't VERIFY_CONSTANT the other operands. */
- if (integer_zerop (val))
- return cxx_eval_constant_expression (call, TREE_OPERAND (t, 2),
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- return cxx_eval_constant_expression (call, TREE_OPERAND (t, 1),
- allow_non_constant, addr,
- non_constant_p, overflow_p);
-}
-
-/* Subroutine of cxx_eval_constant_expression.
- Attempt to reduce a reference to an array slot. */
-
-static tree
-cxx_eval_array_reference (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- tree oldary = TREE_OPERAND (t, 0);
- tree ary = cxx_eval_constant_expression (call, oldary,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- tree index, oldidx;
- HOST_WIDE_INT i;
- tree elem_type;
- unsigned len, elem_nchars = 1;
- if (*non_constant_p)
- return t;
- oldidx = TREE_OPERAND (t, 1);
- index = cxx_eval_constant_expression (call, oldidx,
- allow_non_constant, false,
- non_constant_p, overflow_p);
- VERIFY_CONSTANT (index);
- if (addr && ary == oldary && index == oldidx)
- return t;
- else if (addr)
- return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL);
- elem_type = TREE_TYPE (TREE_TYPE (ary));
- if (TREE_CODE (ary) == CONSTRUCTOR)
- len = CONSTRUCTOR_NELTS (ary);
- else if (TREE_CODE (ary) == STRING_CST)
- {
- elem_nchars = (TYPE_PRECISION (elem_type)
- / TYPE_PRECISION (char_type_node));
- len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars;
- }
- else
- {
- /* We can't do anything with other tree codes, so use
- VERIFY_CONSTANT to complain and fail. */
- VERIFY_CONSTANT (ary);
- gcc_unreachable ();
- }
- if (compare_tree_int (index, len) >= 0)
- {
- if (tree_int_cst_lt (index, array_type_nelts_top (TREE_TYPE (ary))))
- {
- /* If it's within the array bounds but doesn't have an explicit
- initializer, it's value-initialized. */
- tree val = build_value_init (elem_type, tf_warning_or_error);
- return cxx_eval_constant_expression (call, val,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- }
-
- if (!allow_non_constant)
- error ("array subscript out of bound");
- *non_constant_p = true;
- return t;
- }
- else if (tree_int_cst_lt (index, integer_zero_node))
- {
- if (!allow_non_constant)
- error ("negative array subscript");
- *non_constant_p = true;
- return t;
- }
- i = tree_to_shwi (index);
- if (TREE_CODE (ary) == CONSTRUCTOR)
- return (*CONSTRUCTOR_ELTS (ary))[i].value;
- else if (elem_nchars == 1)
- return build_int_cst (cv_unqualified (TREE_TYPE (TREE_TYPE (ary))),
- TREE_STRING_POINTER (ary)[i]);
- else
- {
- tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (ary)));
- return native_interpret_expr (type, (const unsigned char *)
- TREE_STRING_POINTER (ary)
- + i * elem_nchars, elem_nchars);
- }
- /* Don't VERIFY_CONSTANT here. */
-}
-
-/* Subroutine of cxx_eval_constant_expression.
- Attempt to reduce a field access of a value of class type. */
-
-static tree
-cxx_eval_component_reference (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- unsigned HOST_WIDE_INT i;
- tree field;
- tree value;
- tree part = TREE_OPERAND (t, 1);
- tree orig_whole = TREE_OPERAND (t, 0);
- tree whole = cxx_eval_constant_expression (call, orig_whole,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- if (whole == orig_whole)
- return t;
- if (addr)
- return fold_build3 (COMPONENT_REF, TREE_TYPE (t),
- whole, part, NULL_TREE);
- /* Don't VERIFY_CONSTANT here; we only want to check that we got a
- CONSTRUCTOR. */
- if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR)
- {
- if (!allow_non_constant)
- error ("%qE is not a constant expression", orig_whole);
- *non_constant_p = true;
- }
- if (DECL_MUTABLE_P (part))
- {
- if (!allow_non_constant)
- error ("mutable %qD is not usable in a constant expression", part);
- *non_constant_p = true;
- }
- if (*non_constant_p)
- return t;
- FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value)
- {
- if (field == part)
- return value;
- }
- if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE
- && CONSTRUCTOR_NELTS (whole) > 0)
- {
- /* DR 1188 says we don't have to deal with this. */
- if (!allow_non_constant)
- error ("accessing %qD member instead of initialized %qD member in "
- "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index);
- *non_constant_p = true;
- return t;
- }
-
- /* If there's no explicit init for this field, it's value-initialized. */
- value = build_value_init (TREE_TYPE (t), tf_warning_or_error);
- return cxx_eval_constant_expression (call, value,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
-}
-
-/* Subroutine of cxx_eval_constant_expression.
- Attempt to reduce a field access of a value of class type that is
- expressed as a BIT_FIELD_REF. */
-
-static tree
-cxx_eval_bit_field_ref (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- tree orig_whole = TREE_OPERAND (t, 0);
- tree retval, fldval, utype, mask;
- bool fld_seen = false;
- HOST_WIDE_INT istart, isize;
- tree whole = cxx_eval_constant_expression (call, orig_whole,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- tree start, field, value;
- unsigned HOST_WIDE_INT i;
-
- if (whole == orig_whole)
- return t;
- /* Don't VERIFY_CONSTANT here; we only want to check that we got a
- CONSTRUCTOR. */
- if (!*non_constant_p
- && TREE_CODE (whole) != VECTOR_CST
- && TREE_CODE (whole) != CONSTRUCTOR)
- {
- if (!allow_non_constant)
- error ("%qE is not a constant expression", orig_whole);
- *non_constant_p = true;
- }
- if (*non_constant_p)
- return t;
-
- if (TREE_CODE (whole) == VECTOR_CST)
- return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole,
- TREE_OPERAND (t, 1), TREE_OPERAND (t, 2));
-
- start = TREE_OPERAND (t, 2);
- istart = tree_to_shwi (start);
- isize = tree_to_shwi (TREE_OPERAND (t, 1));
- utype = TREE_TYPE (t);
- if (!TYPE_UNSIGNED (utype))
- utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1);
- retval = build_int_cst (utype, 0);
- FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value)
- {
- tree bitpos = bit_position (field);
- if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1))
- return value;
- if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE
- && TREE_CODE (value) == INTEGER_CST
- && tree_fits_shwi_p (bitpos)
- && tree_fits_shwi_p (DECL_SIZE (field)))
- {
- HOST_WIDE_INT bit = tree_to_shwi (bitpos);
- HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field));
- HOST_WIDE_INT shift;
- if (bit >= istart && bit + sz <= istart + isize)
- {
- fldval = fold_convert (utype, value);
- mask = build_int_cst_type (utype, -1);
- mask = fold_build2 (LSHIFT_EXPR, utype, mask,
- size_int (TYPE_PRECISION (utype) - sz));
- mask = fold_build2 (RSHIFT_EXPR, utype, mask,
- size_int (TYPE_PRECISION (utype) - sz));
- fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask);
- shift = bit - istart;
- if (BYTES_BIG_ENDIAN)
- shift = TYPE_PRECISION (utype) - shift - sz;
- fldval = fold_build2 (LSHIFT_EXPR, utype, fldval,
- size_int (shift));
- retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval);
- fld_seen = true;
- }
- }
- }
- if (fld_seen)
- return fold_convert (TREE_TYPE (t), retval);
- gcc_unreachable ();
- return error_mark_node;
-}
-
-/* Subroutine of cxx_eval_constant_expression.
- Evaluate a short-circuited logical expression T in the context
- of a given constexpr CALL. BAILOUT_VALUE is the value for
- early return. CONTINUE_VALUE is used here purely for
- sanity check purposes. */
-
-static tree
-cxx_eval_logical_expression (const constexpr_call *call, tree t,
- tree bailout_value, tree continue_value,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- tree r;
- tree lhs = cxx_eval_constant_expression (call, TREE_OPERAND (t, 0),
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- VERIFY_CONSTANT (lhs);
- if (tree_int_cst_equal (lhs, bailout_value))
- return lhs;
- gcc_assert (tree_int_cst_equal (lhs, continue_value));
- r = cxx_eval_constant_expression (call, TREE_OPERAND (t, 1),
- allow_non_constant, addr, non_constant_p, overflow_p);
- VERIFY_CONSTANT (r);
- return r;
-}
-
-/* REF is a COMPONENT_REF designating a particular field. V is a vector of
- CONSTRUCTOR elements to initialize (part of) an object containing that
- field. Return a pointer to the constructor_elt corresponding to the
- initialization of the field. */
-
-static constructor_elt *
-base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref)
-{
- tree aggr = TREE_OPERAND (ref, 0);
- tree field = TREE_OPERAND (ref, 1);
- HOST_WIDE_INT i;
- constructor_elt *ce;
-
- gcc_assert (TREE_CODE (ref) == COMPONENT_REF);
-
- if (TREE_CODE (aggr) == COMPONENT_REF)
- {
- constructor_elt *base_ce
- = base_field_constructor_elt (v, aggr);
- v = CONSTRUCTOR_ELTS (base_ce->value);
- }
-
- for (i = 0; vec_safe_iterate (v, i, &ce); ++i)
- if (ce->index == field)
- return ce;
-
- gcc_unreachable ();
- return NULL;
-}
-
-/* Subroutine of cxx_eval_constant_expression.
- The expression tree T denotes a C-style array or a C-style
- aggregate. Reduce it to a constant expression. */
-
-static tree
-cxx_eval_bare_aggregate (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t);
- vec<constructor_elt, va_gc> *n;
- vec_alloc (n, vec_safe_length (v));
- constructor_elt *ce;
- HOST_WIDE_INT i;
- bool changed = false;
- gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t));
- for (i = 0; vec_safe_iterate (v, i, &ce); ++i)
- {
- tree elt = cxx_eval_constant_expression (call, ce->value,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- /* Don't VERIFY_CONSTANT here. */
- if (allow_non_constant && *non_constant_p)
- goto fail;
- if (elt != ce->value)
- changed = true;
- if (ce->index && TREE_CODE (ce->index) == COMPONENT_REF)
- {
- /* This is an initialization of a vfield inside a base
- subaggregate that we already initialized; push this
- initialization into the previous initialization. */
- constructor_elt *inner = base_field_constructor_elt (n, ce->index);
- inner->value = elt;
- }
- else if (ce->index
- && (TREE_CODE (ce->index) == NOP_EXPR
- || TREE_CODE (ce->index) == POINTER_PLUS_EXPR))
- {
- /* This is an initializer for an empty base; now that we've
- checked that it's constant, we can ignore it. */
- gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (ce->index))));
- }
- else
- CONSTRUCTOR_APPEND_ELT (n, ce->index, elt);
- }
- if (*non_constant_p || !changed)
- {
- fail:
- vec_free (n);
- return t;
- }
- t = build_constructor (TREE_TYPE (t), n);
- TREE_CONSTANT (t) = true;
- if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
- t = fold (t);
- return t;
-}
-
-/* Subroutine of cxx_eval_constant_expression.
- The expression tree T is a VEC_INIT_EXPR which denotes the desired
- initialization of a non-static data member of array type. Reduce it to a
- CONSTRUCTOR.
-
- Note that apart from value-initialization (when VALUE_INIT is true),
- this is only intended to support value-initialization and the
- initializations done by defaulted constructors for classes with
- non-static data members of array type. In this case, VEC_INIT_EXPR_INIT
- will either be NULL_TREE for the default constructor, or a COMPONENT_REF
- for the copy/move constructor. */
-
-static tree
-cxx_eval_vec_init_1 (const constexpr_call *call, tree atype, tree init,
- bool value_init, bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- tree elttype = TREE_TYPE (atype);
- int max = tree_to_shwi (array_type_nelts (atype));
- vec<constructor_elt, va_gc> *n;
- vec_alloc (n, max + 1);
- bool pre_init = false;
- int i;
-
- /* For the default constructor, build up a call to the default
- constructor of the element type. We only need to handle class types
- here, as for a constructor to be constexpr, all members must be
- initialized, which for a defaulted default constructor means they must
- be of a class type with a constexpr default constructor. */
- if (TREE_CODE (elttype) == ARRAY_TYPE)
- /* We only do this at the lowest level. */;
- else if (value_init)
- {
- init = build_value_init (elttype, tf_warning_or_error);
- init = cxx_eval_constant_expression
- (call, init, allow_non_constant, addr, non_constant_p, overflow_p);
- pre_init = true;
- }
- else if (!init)
- {
- vec<tree, va_gc> *argvec = make_tree_vector ();
- init = build_special_member_call (NULL_TREE, complete_ctor_identifier,
- &argvec, elttype, LOOKUP_NORMAL,
- tf_warning_or_error);
- release_tree_vector (argvec);
- init = cxx_eval_constant_expression (call, init, allow_non_constant,
- addr, non_constant_p, overflow_p);
- pre_init = true;
- }
-
- if (*non_constant_p && !allow_non_constant)
- goto fail;
-
- for (i = 0; i <= max; ++i)
- {
- tree idx = build_int_cst (size_type_node, i);
- tree eltinit;
- if (TREE_CODE (elttype) == ARRAY_TYPE)
- {
- /* A multidimensional array; recurse. */
- if (value_init || init == NULL_TREE)
- eltinit = NULL_TREE;
- else
- eltinit = cp_build_array_ref (input_location, init, idx,
- tf_warning_or_error);
- eltinit = cxx_eval_vec_init_1 (call, elttype, eltinit, value_init,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- }
- else if (pre_init)
- {
- /* Initializing an element using value or default initialization
- we just pre-built above. */
- if (i == 0)
- eltinit = init;
- else
- eltinit = unshare_expr (init);
- }
- else
- {
- /* Copying an element. */
- gcc_assert (same_type_ignoring_top_level_qualifiers_p
- (atype, TREE_TYPE (init)));
- eltinit = cp_build_array_ref (input_location, init, idx,
- tf_warning_or_error);
- if (!real_lvalue_p (init))
- eltinit = move (eltinit);
- eltinit = force_rvalue (eltinit, tf_warning_or_error);
- eltinit = cxx_eval_constant_expression
- (call, eltinit, allow_non_constant, addr, non_constant_p, overflow_p);
- }
- if (*non_constant_p && !allow_non_constant)
- goto fail;
- CONSTRUCTOR_APPEND_ELT (n, idx, eltinit);
- }
-
- if (!*non_constant_p)
- {
- init = build_constructor (atype, n);
- TREE_CONSTANT (init) = true;
- return init;
- }
-
- fail:
- vec_free (n);
- return init;
-}
-
-static tree
-cxx_eval_vec_init (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- tree atype = TREE_TYPE (t);
- tree init = VEC_INIT_EXPR_INIT (t);
- tree r = cxx_eval_vec_init_1 (call, atype, init,
- VEC_INIT_EXPR_VALUE_INIT (t),
- allow_non_constant, addr, non_constant_p, overflow_p);
- if (*non_constant_p)
- return t;
- else
- return r;
-}
-
-/* A less strict version of fold_indirect_ref_1, which requires cv-quals to
- match. We want to be less strict for simple *& folding; if we have a
- non-const temporary that we access through a const pointer, that should
- work. We handle this here rather than change fold_indirect_ref_1
- because we're dealing with things like ADDR_EXPR of INTEGER_CST which
- don't really make sense outside of constant expression evaluation. Also
- we want to allow folding to COMPONENT_REF, which could cause trouble
- with TBAA in fold_indirect_ref_1.
-
- Try to keep this function synced with fold_indirect_ref_1. */
-
-static tree
-cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base)
-{
- tree sub, subtype;
-
- sub = op0;
- STRIP_NOPS (sub);
- subtype = TREE_TYPE (sub);
- if (!POINTER_TYPE_P (subtype))
- return NULL_TREE;
-
- if (TREE_CODE (sub) == ADDR_EXPR)
- {
- tree op = TREE_OPERAND (sub, 0);
- tree optype = TREE_TYPE (op);
-
- /* *&CONST_DECL -> to the value of the const decl. */
- if (TREE_CODE (op) == CONST_DECL)
- return DECL_INITIAL (op);
- /* *&p => p; make sure to handle *&"str"[cst] here. */
- if (same_type_ignoring_top_level_qualifiers_p (optype, type))
- {
- tree fop = fold_read_from_constant_string (op);
- if (fop)
- return fop;
- else
- return op;
- }
- /* *(foo *)&fooarray => fooarray[0] */
- else if (TREE_CODE (optype) == ARRAY_TYPE
- && (same_type_ignoring_top_level_qualifiers_p
- (type, TREE_TYPE (optype))))
- {
- tree type_domain = TYPE_DOMAIN (optype);
- tree min_val = size_zero_node;
- if (type_domain && TYPE_MIN_VALUE (type_domain))
- min_val = TYPE_MIN_VALUE (type_domain);
- return build4_loc (loc, ARRAY_REF, type, op, min_val,
- NULL_TREE, NULL_TREE);
- }
- /* *(foo *)&complexfoo => __real__ complexfoo */
- else if (TREE_CODE (optype) == COMPLEX_TYPE
- && (same_type_ignoring_top_level_qualifiers_p
- (type, TREE_TYPE (optype))))
- return fold_build1_loc (loc, REALPART_EXPR, type, op);
- /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
- else if (TREE_CODE (optype) == VECTOR_TYPE
- && (same_type_ignoring_top_level_qualifiers_p
- (type, TREE_TYPE (optype))))
- {
- tree part_width = TYPE_SIZE (type);
- tree index = bitsize_int (0);
- return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, index);
- }
- /* Also handle conversion to an empty base class, which
- is represented with a NOP_EXPR. */
- else if (is_empty_class (type)
- && CLASS_TYPE_P (optype)
- && DERIVED_FROM_P (type, optype))
- {
- *empty_base = true;
- return op;
- }
- /* *(foo *)&struct_with_foo_field => COMPONENT_REF */
- else if (RECORD_OR_UNION_TYPE_P (optype))
- {
- tree field = TYPE_FIELDS (optype);
- for (; field; field = DECL_CHAIN (field))
- if (TREE_CODE (field) == FIELD_DECL
- && integer_zerop (byte_position (field))
- && (same_type_ignoring_top_level_qualifiers_p
- (TREE_TYPE (field), type)))
- {
- return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE);
- break;
- }
- }
- }
- else if (TREE_CODE (sub) == POINTER_PLUS_EXPR
- && TREE_CODE (TREE_OPERAND (sub, 1)) == INTEGER_CST)
- {
- tree op00 = TREE_OPERAND (sub, 0);
- tree op01 = TREE_OPERAND (sub, 1);
-
- STRIP_NOPS (op00);
- if (TREE_CODE (op00) == ADDR_EXPR)
- {
- tree op00type;
- op00 = TREE_OPERAND (op00, 0);
- op00type = TREE_TYPE (op00);
-
- /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
- if (TREE_CODE (op00type) == VECTOR_TYPE
- && (same_type_ignoring_top_level_qualifiers_p
- (type, TREE_TYPE (op00type))))
- {
- HOST_WIDE_INT offset = tree_to_shwi (op01);
- tree part_width = TYPE_SIZE (type);
- unsigned HOST_WIDE_INT part_widthi = tree_to_shwi (part_width)/BITS_PER_UNIT;
- unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT;
- tree index = bitsize_int (indexi);
-
- if (offset / part_widthi < TYPE_VECTOR_SUBPARTS (op00type))
- return fold_build3_loc (loc,
- BIT_FIELD_REF, type, op00,
- part_width, index);
-
- }
- /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
- else if (TREE_CODE (op00type) == COMPLEX_TYPE
- && (same_type_ignoring_top_level_qualifiers_p
- (type, TREE_TYPE (op00type))))
- {
- tree size = TYPE_SIZE_UNIT (type);
- if (tree_int_cst_equal (size, op01))
- return fold_build1_loc (loc, IMAGPART_EXPR, type, op00);
- }
- /* ((foo *)&fooarray)[1] => fooarray[1] */
- else if (TREE_CODE (op00type) == ARRAY_TYPE
- && (same_type_ignoring_top_level_qualifiers_p
- (type, TREE_TYPE (op00type))))
- {
- tree type_domain = TYPE_DOMAIN (op00type);
- tree min_val = size_zero_node;
- if (type_domain && TYPE_MIN_VALUE (type_domain))
- min_val = TYPE_MIN_VALUE (type_domain);
- op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01,
- TYPE_SIZE_UNIT (type));
- op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val);
- return build4_loc (loc, ARRAY_REF, type, op00, op01,
- NULL_TREE, NULL_TREE);
- }
- /* Also handle conversion to an empty base class, which
- is represented with a NOP_EXPR. */
- else if (is_empty_class (type)
- && CLASS_TYPE_P (op00type)
- && DERIVED_FROM_P (type, op00type))
- {
- *empty_base = true;
- return op00;
- }
- /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */
- else if (RECORD_OR_UNION_TYPE_P (op00type))
- {
- tree field = TYPE_FIELDS (op00type);
- for (; field; field = DECL_CHAIN (field))
- if (TREE_CODE (field) == FIELD_DECL
- && tree_int_cst_equal (byte_position (field), op01)
- && (same_type_ignoring_top_level_qualifiers_p
- (TREE_TYPE (field), type)))
- {
- return fold_build3 (COMPONENT_REF, type, op00,
- field, NULL_TREE);
- break;
- }
- }
- }
- }
- /* *(foo *)fooarrptr => (*fooarrptr)[0] */
- else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE
- && (same_type_ignoring_top_level_qualifiers_p
- (type, TREE_TYPE (TREE_TYPE (subtype)))))
- {
- tree type_domain;
- tree min_val = size_zero_node;
- tree newsub = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL);
- if (newsub)
- sub = newsub;
- else
- sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub);
- type_domain = TYPE_DOMAIN (TREE_TYPE (sub));
- if (type_domain && TYPE_MIN_VALUE (type_domain))
- min_val = TYPE_MIN_VALUE (type_domain);
- return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE,
- NULL_TREE);
- }
-
- return NULL_TREE;
-}
-
-static tree
-cxx_eval_indirect_ref (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- tree orig_op0 = TREE_OPERAND (t, 0);
- tree op0 = cxx_eval_constant_expression (call, orig_op0, allow_non_constant,
- /*addr*/false, non_constant_p, overflow_p);
- bool empty_base = false;
- tree r;
-
- /* Don't VERIFY_CONSTANT here. */
- if (*non_constant_p)
- return t;
-
- r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0,
- &empty_base);
-
- if (r)
- r = cxx_eval_constant_expression (call, r, allow_non_constant,
- addr, non_constant_p, overflow_p);
- else
- {
- tree sub = op0;
- STRIP_NOPS (sub);
- if (TREE_CODE (sub) == ADDR_EXPR)
- {
- /* We couldn't fold to a constant value. Make sure it's not
- something we should have been able to fold. */
- gcc_assert (!same_type_ignoring_top_level_qualifiers_p
- (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t)));
- /* DR 1188 says we don't have to deal with this. */
- if (!allow_non_constant)
- error ("accessing value of %qE through a %qT glvalue in a "
- "constant expression", build_fold_indirect_ref (sub),
- TREE_TYPE (t));
- *non_constant_p = true;
- return t;
- }
- }
-
- /* If we're pulling out the value of an empty base, make sure
- that the whole object is constant and then return an empty
- CONSTRUCTOR. */
- if (empty_base)
- {
- VERIFY_CONSTANT (r);
- r = build_constructor (TREE_TYPE (t), NULL);
- TREE_CONSTANT (r) = true;
- }
-
- if (r == NULL_TREE)
- {
- if (addr && op0 != orig_op0)
- return build1 (INDIRECT_REF, TREE_TYPE (t), op0);
- if (!addr)
- VERIFY_CONSTANT (t);
- return t;
- }
- return r;
-}
-
-/* Complain about R, a VAR_DECL, not being usable in a constant expression.
- Shared between potential_constant_expression and
- cxx_eval_constant_expression. */
-
-static void
-non_const_var_error (tree r)
-{
- tree type = TREE_TYPE (r);
- error ("the value of %qD is not usable in a constant "
- "expression", r);
- /* Avoid error cascade. */
- if (DECL_INITIAL (r) == error_mark_node)
- return;
- if (DECL_DECLARED_CONSTEXPR_P (r))
- inform (DECL_SOURCE_LOCATION (r),
- "%qD used in its own initializer", r);
- else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type))
- {
- if (!CP_TYPE_CONST_P (type))
- inform (DECL_SOURCE_LOCATION (r),
- "%q#D is not const", r);
- else if (CP_TYPE_VOLATILE_P (type))
- inform (DECL_SOURCE_LOCATION (r),
- "%q#D is volatile", r);
- else if (!DECL_INITIAL (r)
- || !TREE_CONSTANT (DECL_INITIAL (r)))
- inform (DECL_SOURCE_LOCATION (r),
- "%qD was not initialized with a constant "
- "expression", r);
- else
- gcc_unreachable ();
- }
- else
- {
- if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r))
- inform (DECL_SOURCE_LOCATION (r),
- "%qD was not declared %<constexpr%>", r);
- else
- inform (DECL_SOURCE_LOCATION (r),
- "%qD does not have integral or enumeration type",
- r);
- }
-}
-
-/* Subroutine of cxx_eval_constant_expression.
- Like cxx_eval_unary_expression, except for trinary expressions. */
-
-static tree
-cxx_eval_trinary_expression (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- int i;
- tree args[3];
- tree val;
-
- for (i = 0; i < 3; i++)
- {
- args[i] = cxx_eval_constant_expression (call, TREE_OPERAND (t, i),
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- VERIFY_CONSTANT (args[i]);
- }
-
- val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t),
- args[0], args[1], args[2]);
- if (val == NULL_TREE)
- return t;
- VERIFY_CONSTANT (val);
- return val;
-}
-
-bool
-var_in_constexpr_fn (tree t)
-{
- tree ctx = DECL_CONTEXT (t);
- return (cxx_dialect >= cxx14 && ctx && TREE_CODE (ctx) == FUNCTION_DECL
- && DECL_DECLARED_CONSTEXPR_P (ctx));
-}
-
-/* Attempt to reduce the expression T to a constant value.
- On failure, issue diagnostic and return error_mark_node. */
-/* FIXME unify with c_fully_fold */
-
-static tree
-cxx_eval_constant_expression (const constexpr_call *call, tree t,
- bool allow_non_constant, bool addr,
- bool *non_constant_p, bool *overflow_p)
-{
- tree r = t;
-
- if (t == error_mark_node)
- {
- *non_constant_p = true;
- return t;
- }
- if (CONSTANT_CLASS_P (t))
- {
- if (TREE_CODE (t) == PTRMEM_CST)
- t = cplus_expand_constant (t);
- else if (TREE_OVERFLOW (t) && (!flag_permissive || allow_non_constant))
- *overflow_p = true;
- return t;
- }
- if (TREE_CODE (t) != NOP_EXPR
- && reduced_constant_expression_p (t))
- return fold (t);
-
- switch (TREE_CODE (t))
- {
- case VAR_DECL:
- if (addr)
- return t;
- /* else fall through. */
- case CONST_DECL:
- r = integral_constant_value (t);
- if (TREE_CODE (r) == TARGET_EXPR
- && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR)
- r = TARGET_EXPR_INITIAL (r);
- if (DECL_P (r) && var_in_constexpr_fn (r)
- && DECL_INITIAL (r))
- r = cxx_eval_constant_expression (call, DECL_INITIAL (r),
- allow_non_constant, false,
- non_constant_p, overflow_p);
- if (DECL_P (r))
- {
- if (!allow_non_constant)
- non_const_var_error (r);
- *non_constant_p = true;
- }
- break;
-
- case FUNCTION_DECL:
- case TEMPLATE_DECL:
- case LABEL_DECL:
- return t;
-
- case PARM_DECL:
- if (call && DECL_CONTEXT (t) == call->fundef->decl)
- {
- if (DECL_ARTIFICIAL (t) && DECL_CONSTRUCTOR_P (DECL_CONTEXT (t)))
- {
- if (!allow_non_constant)
- sorry ("use of the value of the object being constructed "
- "in a constant expression");
- *non_constant_p = true;
- }
- else
- r = lookup_parameter_binding (call, t);
- }
- else if (addr)
- /* Defer in case this is only used for its type. */;
- else
- {
- if (!allow_non_constant)
- error ("%qE is not a constant expression", t);
- *non_constant_p = true;
- }
- break;
-
- case CALL_EXPR:
- case AGGR_INIT_EXPR:
- r = cxx_eval_call_expression (call, t, allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case TARGET_EXPR:
- if (!literal_type_p (TREE_TYPE (t)))
- {
- if (!allow_non_constant)
- {
- error ("temporary of non-literal type %qT in a "
- "constant expression", TREE_TYPE (t));
- explain_non_literal_class (TREE_TYPE (t));
- }
- *non_constant_p = true;
- break;
- }
- /* else fall through. */
- case INIT_EXPR:
- /* Pass false for 'addr' because these codes indicate
- initialization of a temporary. */
- r = cxx_eval_constant_expression (call, TREE_OPERAND (t, 1),
- allow_non_constant, false,
- non_constant_p, overflow_p);
- if (!*non_constant_p)
- /* Adjust the type of the result to the type of the temporary. */
- r = adjust_temp_type (TREE_TYPE (t), r);
- break;
-
- case SCOPE_REF:
- r = cxx_eval_constant_expression (call, TREE_OPERAND (t, 1),
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case RETURN_EXPR:
- case NON_LVALUE_EXPR:
- case TRY_CATCH_EXPR:
- case CLEANUP_POINT_EXPR:
- case MUST_NOT_THROW_EXPR:
- case SAVE_EXPR:
- r = cxx_eval_constant_expression (call, TREE_OPERAND (t, 0),
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- /* These differ from cxx_eval_unary_expression in that this doesn't
- check for a constant operand or result; an address can be
- constant without its operand being, and vice versa. */
- case INDIRECT_REF:
- r = cxx_eval_indirect_ref (call, t, allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case ADDR_EXPR:
- {
- tree oldop = TREE_OPERAND (t, 0);
- tree op = cxx_eval_constant_expression (call, oldop,
- allow_non_constant,
- /*addr*/true,
- non_constant_p, overflow_p);
- /* Don't VERIFY_CONSTANT here. */
- if (*non_constant_p)
- return t;
- /* This function does more aggressive folding than fold itself. */
- r = build_fold_addr_expr_with_type (op, TREE_TYPE (t));
- if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop)
- return t;
- break;
- }
-
- case REALPART_EXPR:
- case IMAGPART_EXPR:
- case CONJ_EXPR:
- case FIX_TRUNC_EXPR:
- case FLOAT_EXPR:
- case NEGATE_EXPR:
- case ABS_EXPR:
- case BIT_NOT_EXPR:
- case TRUTH_NOT_EXPR:
- case FIXED_CONVERT_EXPR:
- r = cxx_eval_unary_expression (call, t, allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case SIZEOF_EXPR:
- if (SIZEOF_EXPR_TYPE_P (t))
- r = cxx_sizeof_or_alignof_type (TREE_TYPE (TREE_OPERAND (t, 0)),
- SIZEOF_EXPR, false);
- else if (TYPE_P (TREE_OPERAND (t, 0)))
- r = cxx_sizeof_or_alignof_type (TREE_OPERAND (t, 0), SIZEOF_EXPR,
- false);
- else
- r = cxx_sizeof_or_alignof_expr (TREE_OPERAND (t, 0), SIZEOF_EXPR,
- false);
- if (r == error_mark_node)
- r = size_one_node;
- VERIFY_CONSTANT (r);
- break;
-
- case COMPOUND_EXPR:
- {
- /* check_return_expr sometimes wraps a TARGET_EXPR in a
- COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR
- introduced by build_call_a. */
- tree op0 = TREE_OPERAND (t, 0);
- tree op1 = TREE_OPERAND (t, 1);
- STRIP_NOPS (op1);
- if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0))
- || TREE_CODE (op1) == EMPTY_CLASS_EXPR)
- r = cxx_eval_constant_expression (call, op0, allow_non_constant,
- addr, non_constant_p, overflow_p);
- else
- {
- /* Check that the LHS is constant and then discard it. */
- cxx_eval_constant_expression (call, op0, allow_non_constant,
- false, non_constant_p, overflow_p);
- op1 = TREE_OPERAND (t, 1);
- r = cxx_eval_constant_expression (call, op1, allow_non_constant,
- addr, non_constant_p, overflow_p);
- }
- }
- break;
-
- case POINTER_PLUS_EXPR:
- case PLUS_EXPR:
- case MINUS_EXPR:
- case MULT_EXPR:
- case TRUNC_DIV_EXPR:
- case CEIL_DIV_EXPR:
- case FLOOR_DIV_EXPR:
- case ROUND_DIV_EXPR:
- case TRUNC_MOD_EXPR:
- case CEIL_MOD_EXPR:
- case ROUND_MOD_EXPR:
- case RDIV_EXPR:
- case EXACT_DIV_EXPR:
- case MIN_EXPR:
- case MAX_EXPR:
- case LSHIFT_EXPR:
- case RSHIFT_EXPR:
- case LROTATE_EXPR:
- case RROTATE_EXPR:
- case BIT_IOR_EXPR:
- case BIT_XOR_EXPR:
- case BIT_AND_EXPR:
- case TRUTH_XOR_EXPR:
- case LT_EXPR:
- case LE_EXPR:
- case GT_EXPR:
- case GE_EXPR:
- case EQ_EXPR:
- case NE_EXPR:
- case UNORDERED_EXPR:
- case ORDERED_EXPR:
- case UNLT_EXPR:
- case UNLE_EXPR:
- case UNGT_EXPR:
- case UNGE_EXPR:
- case UNEQ_EXPR:
- case LTGT_EXPR:
- case RANGE_EXPR:
- case COMPLEX_EXPR:
- r = cxx_eval_binary_expression (call, t, allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- /* fold can introduce non-IF versions of these; still treat them as
- short-circuiting. */
- case TRUTH_AND_EXPR:
- case TRUTH_ANDIF_EXPR:
- r = cxx_eval_logical_expression (call, t, boolean_false_node,
- boolean_true_node,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case TRUTH_OR_EXPR:
- case TRUTH_ORIF_EXPR:
- r = cxx_eval_logical_expression (call, t, boolean_true_node,
- boolean_false_node,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case ARRAY_REF:
- r = cxx_eval_array_reference (call, t, allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case COMPONENT_REF:
- if (is_overloaded_fn (t))
- {
- /* We can only get here in checking mode via
- build_non_dependent_expr, because any expression that
- calls or takes the address of the function will have
- pulled a FUNCTION_DECL out of the COMPONENT_REF. */
- gcc_checking_assert (allow_non_constant || errorcount);
- *non_constant_p = true;
- return t;
- }
- r = cxx_eval_component_reference (call, t, allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case BIT_FIELD_REF:
- r = cxx_eval_bit_field_ref (call, t, allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case COND_EXPR:
- case VEC_COND_EXPR:
- r = cxx_eval_conditional_expression (call, t, allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case CONSTRUCTOR:
- r = cxx_eval_bare_aggregate (call, t, allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case VEC_INIT_EXPR:
- /* We can get this in a defaulted constructor for a class with a
- non-static data member of array type. Either the initializer will
- be NULL, meaning default-initialization, or it will be an lvalue
- or xvalue of the same type, meaning direct-initialization from the
- corresponding member. */
- r = cxx_eval_vec_init (call, t, allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case FMA_EXPR:
- case VEC_PERM_EXPR:
- r = cxx_eval_trinary_expression (call, t, allow_non_constant, addr,
- non_constant_p, overflow_p);
- break;
-
- case CONVERT_EXPR:
- case VIEW_CONVERT_EXPR:
- case NOP_EXPR:
- {
- tree oldop = TREE_OPERAND (t, 0);
- tree op = cxx_eval_constant_expression (call, oldop,
- allow_non_constant, addr,
- non_constant_p, overflow_p);
- if (*non_constant_p)
- return t;
- if (POINTER_TYPE_P (TREE_TYPE (t))
- && TREE_CODE (op) == INTEGER_CST
- && !integer_zerop (op))
- {
- if (!allow_non_constant)
- error_at (EXPR_LOC_OR_LOC (t, input_location),
- "reinterpret_cast from integer to pointer");
- *non_constant_p = true;
- return t;
- }
- if (op == oldop)
- /* We didn't fold at the top so we could check for ptr-int
- conversion. */
- return fold (t);
- r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), op);
- /* Conversion of an out-of-range value has implementation-defined
- behavior; the language considers it different from arithmetic
- overflow, which is undefined. */
- if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op))
- TREE_OVERFLOW (r) = false;
- }
- break;
-
- case EMPTY_CLASS_EXPR:
- /* This is good enough for a function argument that might not get
- used, and they can't do anything with it, so just return it. */
- return t;
-
- case LAMBDA_EXPR:
- case PREINCREMENT_EXPR:
- case POSTINCREMENT_EXPR:
- case PREDECREMENT_EXPR:
- case POSTDECREMENT_EXPR:
- case NEW_EXPR:
- case VEC_NEW_EXPR:
- case DELETE_EXPR:
- case VEC_DELETE_EXPR:
- case THROW_EXPR:
- case MODIFY_EXPR:
- case MODOP_EXPR:
- /* GCC internal stuff. */
- case VA_ARG_EXPR:
- case OBJ_TYPE_REF:
- case WITH_CLEANUP_EXPR:
- case STATEMENT_LIST:
- case BIND_EXPR:
- case NON_DEPENDENT_EXPR:
- case BASELINK:
- case EXPR_STMT:
- case OFFSET_REF:
- if (!allow_non_constant)
- error_at (EXPR_LOC_OR_LOC (t, input_location),
- "expression %qE is not a constant-expression", t);
- *non_constant_p = true;
- break;
-
- default:
- internal_error ("unexpected expression %qE of kind %s", t,
- get_tree_code_name (TREE_CODE (t)));
- *non_constant_p = true;
- break;
- }
-
- if (r == error_mark_node)
- *non_constant_p = true;
-
- if (*non_constant_p)
- return t;
- else
- return r;
-}
-
-static tree
-cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant)
-{
- bool non_constant_p = false;
- bool overflow_p = false;
- tree r = cxx_eval_constant_expression (NULL, t, allow_non_constant,
- false, &non_constant_p, &overflow_p);
-
- verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p);
-
- if (TREE_CODE (t) != CONSTRUCTOR
- && cp_has_mutable_p (TREE_TYPE (t)))
- {
- /* We allow a mutable type if the original expression was a
- CONSTRUCTOR so that we can do aggregate initialization of
- constexpr variables. */
- if (!allow_non_constant)
- error ("%qT cannot be the type of a complete constant expression "
- "because it has mutable sub-objects", TREE_TYPE (t));
- non_constant_p = true;
- }
-
- /* Technically we should check this for all subexpressions, but that
- runs into problems with our internal representation of pointer
- subtraction and the 5.19 rules are still in flux. */
- if (CONVERT_EXPR_CODE_P (TREE_CODE (r))
- && ARITHMETIC_TYPE_P (TREE_TYPE (r))
- && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR)
- {
- if (!allow_non_constant)
- error ("conversion from pointer type %qT "
- "to arithmetic type %qT in a constant-expression",
- TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r));
- non_constant_p = true;
- }
-
- if (!non_constant_p && overflow_p)
- non_constant_p = true;
-
- if (non_constant_p && !allow_non_constant)
- return error_mark_node;
- else if (non_constant_p && TREE_CONSTANT (r))
- {
- /* This isn't actually constant, so unset TREE_CONSTANT. */
- if (EXPR_P (r))
- r = copy_node (r);
- else if (TREE_CODE (r) == CONSTRUCTOR)
- r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r);
- else
- r = build_nop (TREE_TYPE (r), r);
- TREE_CONSTANT (r) = false;
- }
- else if (non_constant_p || r == t)
- return t;
-
- if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r)))
- {
- if (TREE_CODE (t) == TARGET_EXPR
- && TARGET_EXPR_INITIAL (t) == r)
- return t;
- else
- {
- r = get_target_expr (r);
- TREE_CONSTANT (r) = true;
- return r;
- }
- }
- else
- return r;
-}
-
-/* Returns true if T is a valid subexpression of a constant expression,
- even if it isn't itself a constant expression. */
-
-bool
-is_sub_constant_expr (tree t)
-{
- bool non_constant_p = false;
- bool overflow_p = false;
- cxx_eval_constant_expression (NULL, t, true, false, &non_constant_p,
- &overflow_p);
- return !non_constant_p && !overflow_p;
-}
-
-/* If T represents a constant expression returns its reduced value.
- Otherwise return error_mark_node. If T is dependent, then
- return NULL. */
-
-tree
-cxx_constant_value (tree t)
-{
- return cxx_eval_outermost_constant_expr (t, false);
-}
-
-/* If T is a constant expression, returns its reduced value.
- Otherwise, if T does not have TREE_CONSTANT set, returns T.
- Otherwise, returns a version of T without TREE_CONSTANT. */
-
-tree
-maybe_constant_value (tree t)
-{
- tree r;
-
- if (instantiation_dependent_expression_p (t)
- || type_unknown_p (t)
- || BRACE_ENCLOSED_INITIALIZER_P (t)
- || !potential_constant_expression (t))
- {
- if (TREE_OVERFLOW_P (t))
- {
- t = build_nop (TREE_TYPE (t), t);
- TREE_CONSTANT (t) = false;
- }
- return t;
- }
-
- r = cxx_eval_outermost_constant_expr (t, true);
-#ifdef ENABLE_CHECKING
- /* cp_tree_equal looks through NOPs, so allow them. */
- gcc_assert (r == t
- || CONVERT_EXPR_P (t)
- || (TREE_CONSTANT (t) && !TREE_CONSTANT (r))
- || !cp_tree_equal (r, t));
-#endif
- return r;
-}
-
-/* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather
- than wrapped in a TARGET_EXPR. */
-
-tree
-maybe_constant_init (tree t)
-{
- if (TREE_CODE (t) == EXPR_STMT)
- t = TREE_OPERAND (t, 0);
- if (TREE_CODE (t) == CONVERT_EXPR
- && VOID_TYPE_P (TREE_TYPE (t)))
- t = TREE_OPERAND (t, 0);
- t = maybe_constant_value (t);
- if (TREE_CODE (t) == TARGET_EXPR)
- {
- tree init = TARGET_EXPR_INITIAL (t);
- if (TREE_CODE (init) == CONSTRUCTOR)
- t = init;
- }
- return t;
-}
-
-#if 0
-/* FIXME see ADDR_EXPR section in potential_constant_expression_1. */
-/* Return true if the object referred to by REF has automatic or thread
- local storage. */
-
-enum { ck_ok, ck_bad, ck_unknown };
-static int
-check_automatic_or_tls (tree ref)
-{
- enum machine_mode mode;
- HOST_WIDE_INT bitsize, bitpos;
- tree offset;
- int volatilep = 0, unsignedp = 0;
- tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset,
- &mode, &unsignedp, &volatilep, false);
- duration_kind dk;
-
- /* If there isn't a decl in the middle, we don't know the linkage here,
- and this isn't a constant expression anyway. */
- if (!DECL_P (decl))
- return ck_unknown;
- dk = decl_storage_duration (decl);
- return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok;
-}
-#endif
-
-/* Return true if T denotes a potentially constant expression. Issue
- diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true,
- an lvalue-rvalue conversion is implied.
-
- C++0x [expr.const] used to say
-
- 6 An expression is a potential constant expression if it is
- a constant expression where all occurrences of function
- parameters are replaced by arbitrary constant expressions
- of the appropriate type.
-
- 2 A conditional expression is a constant expression unless it
- involves one of the following as a potentially evaluated
- subexpression (3.2), but subexpressions of logical AND (5.14),
- logical OR (5.15), and conditional (5.16) operations that are
- not evaluated are not considered. */
-
-static bool
-potential_constant_expression_1 (tree t, bool want_rval, tsubst_flags_t flags)
-{
- enum { any = false, rval = true };
- int i;
- tree tmp;
-
- if (t == error_mark_node)
- return false;
- if (t == NULL_TREE)
- return true;
- if (TREE_THIS_VOLATILE (t))
- {
- if (flags & tf_error)
- error ("expression %qE has side-effects", t);
- return false;
- }
- if (CONSTANT_CLASS_P (t))
- return true;
-
- switch (TREE_CODE (t))
- {
- case FUNCTION_DECL:
- case BASELINK:
- case TEMPLATE_DECL:
- case OVERLOAD:
- case TEMPLATE_ID_EXPR:
- case LABEL_DECL:
- case LABEL_EXPR:
- case CONST_DECL:
- case SIZEOF_EXPR:
- case ALIGNOF_EXPR:
- case OFFSETOF_EXPR:
- case NOEXCEPT_EXPR:
- case TEMPLATE_PARM_INDEX:
- case TRAIT_EXPR:
- case IDENTIFIER_NODE:
- case USERDEF_LITERAL:
- /* We can see a FIELD_DECL in a pointer-to-member expression. */
- case FIELD_DECL:
- case PARM_DECL:
- case USING_DECL:
- return true;
-
- case AGGR_INIT_EXPR:
- case CALL_EXPR:
- /* -- an invocation of a function other than a constexpr function
- or a constexpr constructor. */
- {
- tree fun = get_function_named_in_call (t);
- const int nargs = call_expr_nargs (t);
- i = 0;
-
- if (is_overloaded_fn (fun))
- {
- if (TREE_CODE (fun) == FUNCTION_DECL)
- {
- if (builtin_valid_in_constant_expr_p (fun))
- return true;
- if (!DECL_DECLARED_CONSTEXPR_P (fun)
- /* Allow any built-in function; if the expansion
- isn't constant, we'll deal with that then. */
- && !is_builtin_fn (fun))
- {
- if (flags & tf_error)
- {
- error_at (EXPR_LOC_OR_LOC (t, input_location),
- "call to non-constexpr function %qD", fun);
- explain_invalid_constexpr_fn (fun);
- }
- return false;
- }
- /* A call to a non-static member function takes the address
- of the object as the first argument. But in a constant
- expression the address will be folded away, so look
- through it now. */
- if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun)
- && !DECL_CONSTRUCTOR_P (fun))
- {
- tree x = get_nth_callarg (t, 0);
- if (is_this_parameter (x))
- {
- if (DECL_CONTEXT (x) == NULL_TREE
- || DECL_CONSTRUCTOR_P (DECL_CONTEXT (x)))
- {
- if (flags & tf_error)
- sorry ("calling a member function of the "
- "object being constructed in a constant "
- "expression");
- return false;
- }
- /* Otherwise OK. */;
- }
- else if (!potential_constant_expression_1 (x, rval, flags))
- return false;
- i = 1;
- }
- }
- else
- {
- if (!potential_constant_expression_1 (fun, true, flags))
- return false;
- fun = get_first_fn (fun);
- }
- /* Skip initial arguments to base constructors. */
- if (DECL_BASE_CONSTRUCTOR_P (fun))
- i = num_artificial_parms_for (fun);
- fun = DECL_ORIGIN (fun);
- }
- else
- {
- if (potential_constant_expression_1 (fun, rval, flags))
- /* Might end up being a constant function pointer. */;
- else
- return false;
- }
- for (; i < nargs; ++i)
- {
- tree x = get_nth_callarg (t, i);
- if (!potential_constant_expression_1 (x, rval, flags))
- return false;
- }
- return true;
- }
-
- case NON_LVALUE_EXPR:
- /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to
- -- an lvalue of integral type that refers to a non-volatile
- const variable or static data member initialized with
- constant expressions, or
-
- -- an lvalue of literal type that refers to non-volatile
- object defined with constexpr, or that refers to a
- sub-object of such an object; */
- return potential_constant_expression_1 (TREE_OPERAND (t, 0), rval, flags);
-
- case VAR_DECL:
- if (want_rval && !decl_constant_var_p (t)
- && !var_in_constexpr_fn (t)
- && !dependent_type_p (TREE_TYPE (t)))
- {
- if (flags & tf_error)
- non_const_var_error (t);
- return false;
- }
- return true;
-
- case NOP_EXPR:
- case CONVERT_EXPR:
- case VIEW_CONVERT_EXPR:
- /* -- a reinterpret_cast. FIXME not implemented, and this rule
- may change to something more specific to type-punning (DR 1312). */
- {
- tree from = TREE_OPERAND (t, 0);
- if (POINTER_TYPE_P (TREE_TYPE (t))
- && TREE_CODE (from) == INTEGER_CST
- && !integer_zerop (from))
- {
- if (flags & tf_error)
- error_at (EXPR_LOC_OR_LOC (t, input_location),
- "reinterpret_cast from integer to pointer");
- return false;
- }
- return (potential_constant_expression_1
- (from, TREE_CODE (t) != VIEW_CONVERT_EXPR, flags));
- }
-
- case ADDR_EXPR:
- /* -- a unary operator & that is applied to an lvalue that
- designates an object with thread or automatic storage
- duration; */
- t = TREE_OPERAND (t, 0);
-
- if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t))
- /* A pointer-to-member constant. */
- return true;
-
-#if 0
- /* FIXME adjust when issue 1197 is fully resolved. For now don't do
- any checking here, as we might dereference the pointer later. If
- we remove this code, also remove check_automatic_or_tls. */
- i = check_automatic_or_tls (t);
- if (i == ck_ok)
- return true;
- if (i == ck_bad)
- {
- if (flags & tf_error)
- error ("address-of an object %qE with thread local or "
- "automatic storage is not a constant expression", t);
- return false;
- }
-#endif
- return potential_constant_expression_1 (t, any, flags);
-
- case COMPONENT_REF:
- case BIT_FIELD_REF:
- case ARROW_EXPR:
- case OFFSET_REF:
- /* -- a class member access unless its postfix-expression is
- of literal type or of pointer to literal type. */
- /* This test would be redundant, as it follows from the
- postfix-expression being a potential constant expression. */
- return potential_constant_expression_1 (TREE_OPERAND (t, 0),
- want_rval, flags);
-
- case EXPR_PACK_EXPANSION:
- return potential_constant_expression_1 (PACK_EXPANSION_PATTERN (t),
- want_rval, flags);
-
- case INDIRECT_REF:
- {
- tree x = TREE_OPERAND (t, 0);
- STRIP_NOPS (x);
- if (is_this_parameter (x))
- {
- if (DECL_CONTEXT (x)
- && !DECL_DECLARED_CONSTEXPR_P (DECL_CONTEXT (x)))
- {
- if (flags & tf_error)
- error ("use of %<this%> in a constant expression");
- return false;
- }
- if (want_rval && DECL_CONTEXT (x)
- && DECL_CONSTRUCTOR_P (DECL_CONTEXT (x)))
- {
- if (flags & tf_error)
- sorry ("use of the value of the object being constructed "
- "in a constant expression");
- return false;
- }
- return true;
- }
- return potential_constant_expression_1 (x, rval, flags);
- }
-
- case LAMBDA_EXPR:
- case DYNAMIC_CAST_EXPR:
- case PSEUDO_DTOR_EXPR:
- case PREINCREMENT_EXPR:
- case POSTINCREMENT_EXPR:
- case PREDECREMENT_EXPR:
- case POSTDECREMENT_EXPR:
- case NEW_EXPR:
- case VEC_NEW_EXPR:
- case DELETE_EXPR:
- case VEC_DELETE_EXPR:
- case THROW_EXPR:
- case MODIFY_EXPR:
- case MODOP_EXPR:
- case OMP_ATOMIC:
- case OMP_ATOMIC_READ:
- case OMP_ATOMIC_CAPTURE_OLD:
- case OMP_ATOMIC_CAPTURE_NEW:
- /* GCC internal stuff. */
- case VA_ARG_EXPR:
- case OBJ_TYPE_REF:
- case WITH_CLEANUP_EXPR:
- case CLEANUP_POINT_EXPR:
- case MUST_NOT_THROW_EXPR:
- case TRY_CATCH_EXPR:
- case STATEMENT_LIST:
- /* Don't bother trying to define a subset of statement-expressions to
- be constant-expressions, at least for now. */
- case STMT_EXPR:
- case EXPR_STMT:
- case BIND_EXPR:
- case TRANSACTION_EXPR:
- case IF_STMT:
- case DO_STMT:
- case FOR_STMT:
- case WHILE_STMT:
- case DECL_EXPR:
- if (flags & tf_error)
- error ("expression %qE is not a constant-expression", t);
- return false;
-
- case TYPEID_EXPR:
- /* -- a typeid expression whose operand is of polymorphic
- class type; */
- {
- tree e = TREE_OPERAND (t, 0);
- if (!TYPE_P (e) && !type_dependent_expression_p (e)
- && TYPE_POLYMORPHIC_P (TREE_TYPE (e)))
- {
- if (flags & tf_error)
- error ("typeid-expression is not a constant expression "
- "because %qE is of polymorphic type", e);
- return false;
- }
- return true;
- }
-
- case MINUS_EXPR:
- /* -- a subtraction where both operands are pointers. */
- if (TYPE_PTR_P (TREE_OPERAND (t, 0))
- && TYPE_PTR_P (TREE_OPERAND (t, 1)))
- {
- if (flags & tf_error)
- error ("difference of two pointer expressions is not "
- "a constant expression");
- return false;
- }
- want_rval = true;
- goto binary;
-
- case LT_EXPR:
- case LE_EXPR:
- case GT_EXPR:
- case GE_EXPR:
- case EQ_EXPR:
- case NE_EXPR:
- /* -- a relational or equality operator where at least
- one of the operands is a pointer. */
- if (TYPE_PTR_P (TREE_OPERAND (t, 0))
- || TYPE_PTR_P (TREE_OPERAND (t, 1)))
- {
- if (flags & tf_error)
- error ("pointer comparison expression is not a "
- "constant expression");
- return false;
- }
- want_rval = true;
- goto binary;
-
- case BIT_NOT_EXPR:
- /* A destructor. */
- if (TYPE_P (TREE_OPERAND (t, 0)))
- return true;
- /* else fall through. */
-
- case REALPART_EXPR:
- case IMAGPART_EXPR:
- case CONJ_EXPR:
- case SAVE_EXPR:
- case FIX_TRUNC_EXPR:
- case FLOAT_EXPR:
- case NEGATE_EXPR:
- case ABS_EXPR:
- case TRUTH_NOT_EXPR:
- case FIXED_CONVERT_EXPR:
- case UNARY_PLUS_EXPR:
- return potential_constant_expression_1 (TREE_OPERAND (t, 0), rval,
- flags);
-
- case CAST_EXPR:
- case CONST_CAST_EXPR:
- case STATIC_CAST_EXPR:
- case REINTERPRET_CAST_EXPR:
- case IMPLICIT_CONV_EXPR:
- if (cxx_dialect < cxx11
- && !dependent_type_p (TREE_TYPE (t))
- && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t)))
- /* In C++98, a conversion to non-integral type can't be part of a
- constant expression. */
- {
- if (flags & tf_error)
- error ("cast to non-integral type %qT in a constant expression",
- TREE_TYPE (t));
- return false;
- }
-
- return (potential_constant_expression_1
- (TREE_OPERAND (t, 0),
- TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE, flags));
-
- case PAREN_EXPR:
- case NON_DEPENDENT_EXPR:
- /* For convenience. */
- case RETURN_EXPR:
- return potential_constant_expression_1 (TREE_OPERAND (t, 0),
- want_rval, flags);
-
- case SCOPE_REF:
- return potential_constant_expression_1 (TREE_OPERAND (t, 1),
- want_rval, flags);
-
- case TARGET_EXPR:
- if (!literal_type_p (TREE_TYPE (t)))
- {
- if (flags & tf_error)
- {
- error ("temporary of non-literal type %qT in a "
- "constant expression", TREE_TYPE (t));
- explain_non_literal_class (TREE_TYPE (t));
- }
- return false;
- }
- case INIT_EXPR:
- return potential_constant_expression_1 (TREE_OPERAND (t, 1),
- rval, flags);
-
- case CONSTRUCTOR:
- {
- vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t);
- constructor_elt *ce;
- for (i = 0; vec_safe_iterate (v, i, &ce); ++i)
- if (!potential_constant_expression_1 (ce->value, want_rval, flags))
- return false;
- return true;
- }
-
- case TREE_LIST:
- {
- gcc_assert (TREE_PURPOSE (t) == NULL_TREE
- || DECL_P (TREE_PURPOSE (t)));
- if (!potential_constant_expression_1 (TREE_VALUE (t), want_rval,
- flags))
- return false;
- if (TREE_CHAIN (t) == NULL_TREE)
- return true;
- return potential_constant_expression_1 (TREE_CHAIN (t), want_rval,
- flags);
- }
-
- case TRUNC_DIV_EXPR:
- case CEIL_DIV_EXPR:
- case FLOOR_DIV_EXPR:
- case ROUND_DIV_EXPR:
- case TRUNC_MOD_EXPR:
- case CEIL_MOD_EXPR:
- case ROUND_MOD_EXPR:
- {
- tree denom = TREE_OPERAND (t, 1);
- if (!potential_constant_expression_1 (denom, rval, flags))
- return false;
- /* We can't call cxx_eval_outermost_constant_expr on an expression
- that hasn't been through fold_non_dependent_expr yet. */
- if (!processing_template_decl)
- denom = cxx_eval_outermost_constant_expr (denom, true);
- if (integer_zerop (denom))
- {
- if (flags & tf_error)
- error ("division by zero is not a constant-expression");
- return false;
- }
- else
- {
- want_rval = true;
- return potential_constant_expression_1 (TREE_OPERAND (t, 0),
- want_rval, flags);
- }
- }
-
- case COMPOUND_EXPR:
- {
- /* check_return_expr sometimes wraps a TARGET_EXPR in a
- COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR
- introduced by build_call_a. */
- tree op0 = TREE_OPERAND (t, 0);
- tree op1 = TREE_OPERAND (t, 1);
- STRIP_NOPS (op1);
- if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0))
- || TREE_CODE (op1) == EMPTY_CLASS_EXPR)
- return potential_constant_expression_1 (op0, want_rval, flags);
- else
- goto binary;
- }
-
- /* If the first operand is the non-short-circuit constant, look at
- the second operand; otherwise we only care about the first one for
- potentiality. */
- case TRUTH_AND_EXPR:
- case TRUTH_ANDIF_EXPR:
- tmp = boolean_true_node;
- goto truth;
- case TRUTH_OR_EXPR:
- case TRUTH_ORIF_EXPR:
- tmp = boolean_false_node;
- truth:
- {
- tree op = TREE_OPERAND (t, 0);
- if (!potential_constant_expression_1 (op, rval, flags))
- return false;
- if (!processing_template_decl)
- op = cxx_eval_outermost_constant_expr (op, true);
- if (tree_int_cst_equal (op, tmp))
- return potential_constant_expression_1 (TREE_OPERAND (t, 1), rval, flags);
- else
- return true;
- }
-
- case PLUS_EXPR:
- case MULT_EXPR:
- case POINTER_PLUS_EXPR:
- case RDIV_EXPR:
- case EXACT_DIV_EXPR:
- case MIN_EXPR:
- case MAX_EXPR:
- case LSHIFT_EXPR:
- case RSHIFT_EXPR:
- case LROTATE_EXPR:
- case RROTATE_EXPR:
- case BIT_IOR_EXPR:
- case BIT_XOR_EXPR:
- case BIT_AND_EXPR:
- case TRUTH_XOR_EXPR:
- case UNORDERED_EXPR:
- case ORDERED_EXPR:
- case UNLT_EXPR:
- case UNLE_EXPR:
- case UNGT_EXPR:
- case UNGE_EXPR:
- case UNEQ_EXPR:
- case LTGT_EXPR:
- case RANGE_EXPR:
- case COMPLEX_EXPR:
- want_rval = true;
- /* Fall through. */
- case ARRAY_REF:
- case ARRAY_RANGE_REF:
- case MEMBER_REF:
- case DOTSTAR_EXPR:
- binary:
- for (i = 0; i < 2; ++i)
- if (!potential_constant_expression_1 (TREE_OPERAND (t, i),
- want_rval, flags))
- return false;
- return true;
-
- case CILK_SYNC_STMT:
- case CILK_SPAWN_STMT:
- case ARRAY_NOTATION_REF:
- return false;
-
- case FMA_EXPR:
- case VEC_PERM_EXPR:
- for (i = 0; i < 3; ++i)
- if (!potential_constant_expression_1 (TREE_OPERAND (t, i),
- true, flags))
- return false;
- return true;
-
- case COND_EXPR:
- case VEC_COND_EXPR:
- /* If the condition is a known constant, we know which of the legs we
- care about; otherwise we only require that the condition and
- either of the legs be potentially constant. */
- tmp = TREE_OPERAND (t, 0);
- if (!potential_constant_expression_1 (tmp, rval, flags))
- return false;
- if (!processing_template_decl)
- tmp = cxx_eval_outermost_constant_expr (tmp, true);
- if (integer_zerop (tmp))
- return potential_constant_expression_1 (TREE_OPERAND (t, 2),
- want_rval, flags);
- else if (TREE_CODE (tmp) == INTEGER_CST)
- return potential_constant_expression_1 (TREE_OPERAND (t, 1),
- want_rval, flags);
- for (i = 1; i < 3; ++i)
- if (potential_constant_expression_1 (TREE_OPERAND (t, i),
- want_rval, tf_none))
- return true;
- if (flags & tf_error)
- error ("expression %qE is not a constant-expression", t);
- return false;
-
- case VEC_INIT_EXPR:
- if (VEC_INIT_EXPR_IS_CONSTEXPR (t))
- return true;
- if (flags & tf_error)
- {
- error ("non-constant array initialization");
- diagnose_non_constexpr_vec_init (t);
- }
- return false;
-
- default:
- if (objc_is_property_ref (t))
- return false;
-
- sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t)));
- gcc_unreachable();
- return false;
- }
-}
-
-/* The main entry point to the above. */
-
-bool
-potential_constant_expression (tree t)
-{
- return potential_constant_expression_1 (t, false, tf_none);
-}
-
-/* As above, but require a constant rvalue. */
-
-bool
-potential_rvalue_constant_expression (tree t)
-{
- return potential_constant_expression_1 (t, true, tf_none);
-}
-
-/* Like above, but complain about non-constant expressions. */
-
-bool
-require_potential_constant_expression (tree t)
-{
- return potential_constant_expression_1 (t, false, tf_warning_or_error);
-}
-
-/* Cross product of the above. */
-
-bool
-require_potential_rvalue_constant_expression (tree t)
-{
- return potential_constant_expression_1 (t, true, tf_warning_or_error);
-}
-\f
/* Insert the deduced return type for an auto function. */
void
projects / gcc.git / commitdiff