+2018-09-18 Marek Polacek <polacek@redhat.com>
+
+ P1064R0 - Allowing Virtual Function Calls in Constant Expressions
+ * gimple-fold.c (gimple_get_virt_method_for_vtable): Adjust assert.
+
2018-09-18 Segher Boessenkool <segher@kernel.crashing.org>
* config/rs6000/rs6000.md: Remove old "Cygnus sibcall" comment.
+2018-09-18 Marek Polacek <polacek@redhat.com>
+
+ P1064R0 - Allowing Virtual Function Calls in Constant Expressions
+ * call.c (build_over_call): No longer check if we're outside a template
+ function.
+ * class.c (build_vtbl_initializer): Build vtable's constructor with
+ indexes.
+ * constexpr.c (cxx_eval_constant_expression): Don't ignore _vptr's
+ initializer. Handle OBJ_TYPE_REF.
+ (potential_constant_expression_1): Handle OBJ_TYPE_REF.
+ * decl.c (maybe_commonize_var): Bail out for any DECL_ARTIFICIAL.
+ (initialize_artificial_var): Mark the variable as constexpr.
+ (grokdeclarator): Change error to pedwarn. Only warn when
+ pedantic and not C++2a.
+
2018-09-18 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/85065
&& DECL_BUILT_IN_CLASS (fn) == BUILT_IN_NORMAL)
maybe_warn_class_memaccess (input_location, fn, args);
- if (DECL_VINDEX (fn) && (flags & LOOKUP_NONVIRTUAL) == 0
- /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
- virtual functions can't be constexpr. */
- && !in_template_function ())
+ if (DECL_VINDEX (fn) && (flags & LOOKUP_NONVIRTUAL) == 0)
{
tree t;
tree binfo = lookup_base (TREE_TYPE (TREE_TYPE (argarray[0])),
tree vcall_index;
tree fn, fn_original;
tree init = NULL_TREE;
+ tree idx = size_int (jx++);
fn = BV_FN (v);
fn_original = fn;
int i;
if (init == size_zero_node)
for (i = 0; i < TARGET_VTABLE_USES_DESCRIPTORS; ++i)
- CONSTRUCTOR_APPEND_ELT (*inits, NULL_TREE, init);
+ CONSTRUCTOR_APPEND_ELT (*inits, idx, init);
else
for (i = 0; i < TARGET_VTABLE_USES_DESCRIPTORS; ++i)
{
fn, build_int_cst (NULL_TREE, i));
TREE_CONSTANT (fdesc) = 1;
- CONSTRUCTOR_APPEND_ELT (*inits, NULL_TREE, fdesc);
+ CONSTRUCTOR_APPEND_ELT (*inits, idx, fdesc);
}
}
else
- CONSTRUCTOR_APPEND_ELT (*inits, NULL_TREE, init);
+ CONSTRUCTOR_APPEND_ELT (*inits, idx, init);
}
}
CONST_DECL for aggregate constants. */
if (lval)
return t;
+ /* is_really_empty_class doesn't take into account _vptr, so initializing
+ otherwise empty class with { } would overwrite the initializer that
+ initialize_vtable created for us. */
if (COMPLETE_TYPE_P (TREE_TYPE (t))
+ && !TYPE_POLYMORPHIC_P (TREE_TYPE (t))
&& is_really_empty_class (TREE_TYPE (t)))
{
/* If the class is empty, we aren't actually loading anything. */
case MODOP_EXPR:
/* GCC internal stuff. */
case VA_ARG_EXPR:
- case OBJ_TYPE_REF:
case NON_DEPENDENT_EXPR:
case BASELINK:
case OFFSET_REF:
*non_constant_p = true;
break;
+ case OBJ_TYPE_REF:
+ {
+ /* Virtual function call. Let the constexpr machinery figure out
+ the dynamic type. */
+ int token = tree_to_shwi (OBJ_TYPE_REF_TOKEN (t));
+ tree obj = OBJ_TYPE_REF_OBJECT (t);
+ obj = cxx_eval_constant_expression (ctx, obj, lval, non_constant_p,
+ overflow_p);
+ /* We expect something in the form of &x.D.2103.D.2094; get x. */
+ if (TREE_CODE (obj) != ADDR_EXPR)
+ {
+ if (!ctx->quiet)
+ error_at (cp_expr_loc_or_loc (t, input_location),
+ "expression %qE is not a constant expression", t);
+ *non_constant_p = true;
+ return t;
+ }
+ obj = TREE_OPERAND (obj, 0);
+ while (handled_component_p (obj))
+ obj = TREE_OPERAND (obj, 0);
+ tree objtype = TREE_TYPE (obj);
+ /* Find the function decl in the virtual functions list. TOKEN is
+ the DECL_VINDEX that says which function we're looking for. */
+ tree virtuals = BINFO_VIRTUALS (TYPE_BINFO (objtype));
+ r = TREE_VALUE (chain_index (token, virtuals));
+ break;
+ }
+
case PLACEHOLDER_EXPR:
/* Use of the value or address of the current object. */
if (tree ctor = lookup_placeholder (ctx, lval, TREE_TYPE (t)))
case OACC_UPDATE:
/* GCC internal stuff. */
case VA_ARG_EXPR:
- case OBJ_TYPE_REF:
case TRANSACTION_EXPR:
case ASM_EXPR:
case AT_ENCODE_EXPR:
error_at (loc, "expression %qE is not a constant expression", t);
return false;
+ case OBJ_TYPE_REF:
+ if (cxx_dialect >= cxx2a)
+ /* In C++2a virtual calls can be constexpr, don't give up yet. */
+ return true;
+ else if (flags & tf_error)
+ error_at (loc, "virtual functions cannot be constexpr before C++2a");
+ return false;
+
case TYPEID_EXPR:
/* -- a typeid expression whose operand is of polymorphic
class type; */
void
maybe_commonize_var (tree decl)
{
+ /* Don't mess with __FUNCTION__ and similar. */
+ if (DECL_ARTIFICIAL (decl))
+ return;
+
/* Static data in a function with comdat linkage also has comdat
linkage. */
if ((TREE_STATIC (decl)
- /* Don't mess with __FUNCTION__. */
- && ! DECL_ARTIFICIAL (decl)
&& DECL_FUNCTION_SCOPE_P (decl)
&& vague_linkage_p (DECL_CONTEXT (decl)))
|| (TREE_PUBLIC (decl) && DECL_INLINE_VAR_P (decl)))
gcc_assert (TREE_CODE (init) == CONSTRUCTOR);
DECL_INITIAL (decl) = init;
DECL_INITIALIZED_P (decl) = 1;
+ /* Mark the decl as constexpr so that we can access its content
+ at compile time. */
+ DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl) = true;
+ DECL_DECLARED_CONSTEXPR_P (decl) = true;
determine_visibility (decl);
layout_var_decl (decl);
maybe_commonize_var (decl);
storage_class = sc_none;
staticp = 0;
}
- if (constexpr_p)
+ if (constexpr_p && cxx_dialect < cxx2a)
{
gcc_rich_location richloc (declspecs->locations[ds_virtual]);
richloc.add_range (declspecs->locations[ds_constexpr]);
- error_at (&richloc, "member %qD cannot be declared both %<virtual%> "
- "and %<constexpr%>", dname);
+ pedwarn (&richloc, OPT_Wpedantic, "member %qD can be declared both "
+ "%<virtual%> and %<constexpr%> only in -std=c++2a or "
+ "-std=gnu++2a", dname);
}
}
friendp = decl_spec_seq_has_spec_p (declspecs, ds_friend);
access_index = offset / BITS_PER_UNIT / elt_size;
gcc_checking_assert (offset % (elt_size * BITS_PER_UNIT) == 0);
- /* This code makes an assumption that there are no
- indexed fileds produced by C++ FE, so we can directly index the array. */
+ /* The C++ FE can now produce indexed fields, and we check if the indexes
+ match. */
if (access_index < CONSTRUCTOR_NELTS (init))
{
fn = CONSTRUCTOR_ELT (init, access_index)->value;
- gcc_checking_assert (!CONSTRUCTOR_ELT (init, access_index)->index);
+ tree idx = CONSTRUCTOR_ELT (init, access_index)->index;
+ gcc_checking_assert (!idx || tree_to_uhwi (idx) == access_index);
STRIP_NOPS (fn);
}
else
+2018-09-18 Marek Polacek <polacek@redhat.com>
+
+ P1064R0 - Allowing Virtual Function Calls in Constant Expressions
+ * g++.dg/cpp0x/constexpr-virtual5.C: Adjust dg-error.
+ * g++.dg/cpp2a/constexpr-virtual1.C: New test.
+ * g++.dg/cpp2a/constexpr-virtual2.C: New test.
+ * g++.dg/cpp2a/constexpr-virtual3.C: New test.
+ * g++.dg/cpp2a/constexpr-virtual4.C: New test.
+ * g++.dg/cpp2a/constexpr-virtual5.C: New test.
+ * g++.dg/cpp2a/constexpr-virtual6.C: New test.
+ * g++.dg/cpp2a/constexpr-virtual7.C: New test.
+ * g++.dg/cpp2a/constexpr-virtual8.C: New test.
+ * g++.dg/cpp2a/constexpr-virtual9.C: New test.
+ * g++.dg/diagnostic/virtual-constexpr.C: Skip for C++2a. Use
+ -pedantic-errors. Adjust dg-error.
+
2018-09-18 Paul Thomas <pault@gcc.gnu.org>
PR fortran/87336
// { dg-do compile { target c++11 } }
struct S {
- constexpr virtual int f() { return 1; } // { dg-error "13:member .f. cannot be declared both .virtual. and .constexpr." }
+ constexpr virtual int f() { return 1; } // { dg-error "13:member .f. can be declared both .virtual. and .constexpr." "" { target c++17_down } }
};
--- /dev/null
+// P1064R0
+// { dg-do compile { target c++11 } }
+// { dg-options "-pedantic-errors" }
+
+struct X
+{
+ constexpr virtual int f() { return 0; } // { dg-error "member .f. can be declared both .virtual. and .constexpr. only" "" { target c++17_down } }
+};
--- /dev/null
+// P1064R0
+// { dg-do compile }
+// { dg-options "-std=c++2a" }
+
+struct X1
+{
+ virtual int f() const = 0;
+};
+
+struct X2: public X1
+{
+ constexpr virtual int f() const { return 2; }
+};
+
+struct X3: public X2
+{
+ virtual int f() const { return 3; }
+};
+
+struct X4: public X3
+{
+ constexpr virtual int f() const { return 4; }
+};
+
+constexpr int (X1::*pf)() const = &X1::f;
+
+constexpr X2 x2;
+static_assert(x2.f() == 2);
+static_assert((x2.*pf)() == 2);
+
+constexpr X1 const& r2 = x2;
+static_assert(r2.f() == 2);
+static_assert((r2.*pf)() == 2);
+
+constexpr X1 const* p2 = &x2;
+static_assert(p2->f() == 2);
+static_assert((p2->*pf)() == 2);
+
+constexpr X4 x4;
+static_assert(x4.f() == 4);
+static_assert((x4.*pf)() == 4);
+
+constexpr X1 const& r4 = x4;
+static_assert(r4.f() == 4);
+static_assert((r4.*pf)() == 4);
+
+constexpr X1 const* p4 = &x4;
+static_assert(p4->f() == 4);
+static_assert((p4->*pf)() == 4);
--- /dev/null
+// P1064R0
+// { dg-do compile }
+// { dg-options "-std=c++2a" }
+
+struct X1
+{
+ virtual int f() const = 0;
+};
+
+struct X2: public X1
+{
+ int i2 = 42;
+ constexpr virtual int f() const { return 2; }
+};
+
+struct X3: public X2
+{
+ int i3 = 42;
+ virtual int f() const { return 3; }
+};
+
+struct X4: public X3
+{
+ int i4 = 42;
+ constexpr virtual int f() const { return 4; }
+};
+
+constexpr int (X1::*pf)() const = &X1::f;
+
+constexpr X2 x2;
+static_assert(x2.f() == 2);
+static_assert((x2.*pf)() == 2);
+
+constexpr X1 const& r2 = x2;
+static_assert(r2.f() == 2);
+static_assert((r2.*pf)() == 2);
+
+constexpr X1 const* p2 = &x2;
+static_assert(p2->f() == 2);
+static_assert((p2->*pf)() == 2);
+
+constexpr X4 x4;
+static_assert(x4.f() == 4);
+static_assert((x4.*pf)() == 4);
+
+constexpr X1 const& r4 = x4;
+static_assert(r4.f() == 4);
+static_assert((r4.*pf)() == 4);
+
+constexpr X1 const* p4 = &x4;
+static_assert(p4->f() == 4);
+static_assert((p4->*pf)() == 4);
--- /dev/null
+// P1064R0
+// { dg-do compile }
+// { dg-options "-std=c++2a" }
+
+struct X1
+{
+ virtual int f1() const = 0;
+ virtual int f2() const = 0;
+ virtual int f3() const = 0;
+};
+
+struct X2: public X1
+{
+ constexpr virtual int f1() const { return 21; }
+ constexpr virtual int f2() const { return 22; }
+ constexpr virtual int f3() const { return 23; }
+};
+
+struct X3: public X2
+{
+ virtual int f1() const { return 31; }
+ virtual int f2() const { return 32; }
+ virtual int f3() const { return 33; }
+};
+
+struct X4: public X3
+{
+ constexpr virtual int f1() const { return 41; }
+ constexpr virtual int f2() const { return 42; }
+ constexpr virtual int f3() const { return 43; }
+};
+
+constexpr int (X1::*pf)() const = &X1::f2;
+
+constexpr X2 x2;
+static_assert(x2.f2() == 22);
+static_assert((x2.*pf)() == 22);
+
+constexpr X1 const& r2 = x2;
+static_assert(r2.f2() == 22);
+static_assert((r2.*pf)() == 22);
+
+constexpr X1 const* p2 = &x2;
+static_assert(p2->f2() == 22);
+static_assert((p2->*pf)() == 22);
+
+constexpr X4 x4;
+static_assert(x4.f2() == 42);
+static_assert((x4.*pf)() == 42);
+
+constexpr X1 const& r4 = x4;
+static_assert(r4.f2() == 42);
+static_assert((r4.*pf)() == 42);
+
+constexpr X1 const* p4 = &x4;
+static_assert(p4->f2() == 42);
+static_assert((p4->*pf)() == 42);
--- /dev/null
+// P1064R0
+// { dg-do compile }
+// { dg-options "-std=c++2a" }
+
+struct X1
+{
+ virtual int f1() const = 0;
+ virtual int f2() const = 0;
+ virtual int f3() const = 0;
+};
+
+struct X2: public X1
+{
+ int i2 = 42;
+ constexpr virtual int f1() const { return 21; }
+ constexpr virtual int f2() const { return 22; }
+ constexpr virtual int f3() const { return 23; }
+};
+
+struct X3: public X2
+{
+ int i3 = 42;
+ virtual int f1() const { return 31; }
+ virtual int f2() const { return 32; }
+ virtual int f3() const { return 33; }
+};
+
+struct X4: public X3
+{
+ int i4 = 42;
+ constexpr virtual int f1() const { return 41; }
+ constexpr virtual int f2() const { return 42; }
+ constexpr virtual int f3() const { return 43; }
+};
+
+constexpr int (X1::*pf)() const = &X1::f2;
+
+constexpr X2 x2;
+static_assert(x2.f2() == 22);
+static_assert((x2.*pf)() == 22);
+
+constexpr X1 const& r2 = x2;
+static_assert(r2.f2() == 22);
+static_assert((r2.*pf)() == 22);
+
+constexpr X1 const* p2 = &x2;
+static_assert(p2->f2() == 22);
+static_assert((p2->*pf)() == 22);
+
+constexpr X4 x4;
+static_assert(x4.f2() == 42);
+static_assert((x4.*pf)() == 42);
+
+constexpr X1 const& r4 = x4;
+static_assert(r4.f2() == 42);
+static_assert((r4.*pf)() == 42);
+
+constexpr X1 const* p4 = &x4;
+static_assert(p4->f2() == 42);
+static_assert((p4->*pf)() == 42);
--- /dev/null
+// P1064R0
+// { dg-do compile }
+// { dg-options "-std=c++2a" }
+
+struct X1
+{
+ constexpr virtual X1 const *f() const { return this; }
+};
+
+struct Y
+{
+ int m = 0;
+};
+
+struct X2: public Y, public X1
+{
+ constexpr virtual X2 const *f() const { return this; }
+};
+
+constexpr X1 x1;
+static_assert(x1.f() == &x1);
+
+constexpr X2 x2;
+constexpr X1 const& r2 = x2;
+static_assert(r2.f() == &r2);
--- /dev/null
+// P1064R0
+// { dg-do compile }
+// { dg-options "-std=c++2a" }
+
+struct X1
+{
+ virtual int f() const = 0;
+};
+
+struct X2: public X1
+{
+ constexpr virtual int f() const { return 2; }
+};
+
+struct X3: public X2
+{
+ virtual int f() const { return 3; }
+};
+
+struct X4: public X3
+{
+ constexpr virtual int f() const { return 4; }
+};
+
+constexpr int (X1::*pf)() const = &X1::f;
+
+constexpr X2 x2;
+
+struct S
+{
+ int i, j;
+ constexpr S() : i(x2.f()), j((x2.*pf)()) { }
+};
+
+static_assert(S().i == 2);
+static_assert(S().j == 2);
+
+constexpr X1 const& r2 = x2;
+
+struct S2
+{
+ int i, j;
+ constexpr S2() : i(r2.f()), j((r2.*pf)()) { }
+};
+
+static_assert(S2().i == 2);
+static_assert(S2().j == 2);
+
+constexpr X1 const* p2 = &x2;
+struct S3
+{
+ int i, j;
+ constexpr S3() : i(p2->f()), j((p2->*pf)()) { }
+};
+
+static_assert(S3().i == 2);
+static_assert(S3().j == 2);
+
+constexpr X4 x4;
+struct S4
+{
+ int i, j;
+ constexpr S4() : i(x4.f()), j((x4.*pf)()) { }
+};
+
+static_assert(S4().i == 4);
+static_assert(S4().j == 4);
+
+constexpr X1 const& r4 = x4;
+struct S5
+{
+ int i, j;
+ constexpr S5() : i(r4.f()), j((r4.*pf)()) { }
+};
+
+static_assert(S5().i == 4);
+static_assert(S5().j == 4);
+
+constexpr X1 const* p4 = &x4;
+struct S6
+{
+ int i, j;
+ constexpr S6() : i(p4->f()), j((p4->*pf)()) { }
+};
+
+static_assert(S6().i == 4);
+static_assert(S6().j == 4);
--- /dev/null
+// P1064R0
+// { dg-do compile }
+// { dg-options "-std=c++2a" }
+
+template<typename T>
+struct X1
+{
+ virtual T f() const = 0;
+};
+
+struct X2: public X1<int>
+{
+ constexpr virtual int f() const { return 2; }
+};
+
+struct X3: public X2
+{
+ virtual int f() const { return 3; }
+};
+
+struct X4: public X3
+{
+ constexpr virtual int f() const { return 4; }
+};
+
+constexpr int (X1<int>::*pf)() const = &X1<int>::f;
+
+constexpr X2 x2;
+static_assert(x2.f() == 2);
+static_assert((x2.*pf)() == 2);
+
+constexpr X1<int> const& r2 = x2;
+static_assert(r2.f() == 2);
+static_assert((r2.*pf)() == 2);
+
+constexpr X1<int> const* p2 = &x2;
+static_assert(p2->f() == 2);
+static_assert((p2->*pf)() == 2);
+
+constexpr X4 x4;
+static_assert(x4.f() == 4);
+static_assert((x4.*pf)() == 4);
+
+constexpr X1<int> const& r4 = x4;
+static_assert(r4.f() == 4);
+static_assert((r4.*pf)() == 4);
+
+constexpr X1<int> const* p4 = &x4;
+static_assert(p4->f() == 4);
+static_assert((p4->*pf)() == 4);
--- /dev/null
+// P1064R0
+// { dg-do compile }
+// { dg-options "-std=c++2a" }
+
+struct X1
+{
+ virtual int f() const = 0;
+ virtual int f(int) const = 0;
+ virtual int f(int, int) const = 0;
+};
+
+struct X2: public X1
+{
+ constexpr virtual int f() const { return 2; }
+ constexpr virtual int f(int) const { return 12; }
+ constexpr virtual int f(int, int) const { return 22; }
+};
+
+struct X3: public X2
+{
+ virtual int f() const { return 3; }
+ virtual int f(int) const { return 13; }
+ virtual int f(int, int) const { return 23; }
+};
+
+struct X4: public X3
+{
+ constexpr virtual int f() const { return 4; }
+ constexpr virtual int f(int) const { return 14; }
+ constexpr virtual int f(int, int) const { return 24; }
+};
+
+constexpr int (X1::*pf)() const = &X1::f;
+constexpr int (X1::*pf1)(int) const = &X1::f;
+constexpr int (X1::*pf2)(int, int) const = &X1::f;
+
+constexpr X2 x2;
+static_assert(x2.f() == 2);
+static_assert((x2.*pf)() == 2);
+static_assert(x2.f(1) == 12);
+static_assert((x2.*pf1)(1) == 12);
+static_assert(x2.f(1, 2) == 22);
+static_assert((x2.*pf2)(1, 2) == 22);
+
+constexpr X1 const& r2 = x2;
+static_assert(r2.f() == 2);
+static_assert((r2.*pf)() == 2);
+static_assert(r2.f(1) == 12);
+static_assert((r2.*pf1)(1) == 12);
+static_assert(r2.f(1, 2) == 22);
+static_assert((r2.*pf2)(1, 2) == 22);
+
+constexpr X1 const* p2 = &x2;
+static_assert(p2->f() == 2);
+static_assert((p2->*pf)() == 2);
+static_assert(p2->f(1) == 12);
+static_assert((p2->*pf1)(1) == 12);
+static_assert(p2->f(1, 2) == 22);
+static_assert((p2->*pf2)(1, 2) == 22);
+
+constexpr X4 x4;
+static_assert(x4.f() == 4);
+static_assert((x4.*pf)() == 4);
+static_assert(x4.f(1) == 14);
+static_assert((x4.*pf1)(1) == 14);
+static_assert(x4.f(1, 2) == 24);
+static_assert((x4.*pf2)(1, 2) == 24);
+
+constexpr X1 const& r4 = x4;
+static_assert(r4.f() == 4);
+static_assert((r4.*pf)() == 4);
+static_assert(r4.f(1) == 14);
+static_assert((r4.*pf1)(1) == 14);
+static_assert(r4.f(1, 2) == 24);
+static_assert((r4.*pf2)(1, 2) == 24);
+
+constexpr X1 const* p4 = &x4;
+static_assert(p4->f() == 4);
+static_assert((p4->*pf)() == 4);
+static_assert(p4->f(1) == 14);
+static_assert((p4->*pf1)(1) == 14);
+static_assert(p4->f(1, 2) == 24);
+static_assert((p4->*pf2)(1, 2) == 24);
-// { dg-options "-fdiagnostics-show-caret" }
+// { dg-options "-fdiagnostics-show-caret -pedantic-errors" }
// { dg-do compile { target c++11 } }
+// { dg-skip-if "virtual constexpr" { *-*-* } { "-std=gnu++2a" } { "" } }
struct S
{
- virtual constexpr void foo(); // { dg-error "3:member .foo. cannot be declared both .virtual. and .constexpr." }
+ virtual constexpr void foo(); // { dg-error "3:member .foo. can be declared both .virtual. and .constexpr." }
/* { dg-begin-multiline-output "" }
virtual constexpr void foo();
^~~~~~~ ~~~~~~~~~
{ dg-end-multiline-output "" } */
- constexpr virtual void bar(); // { dg-error "13:member .bar. cannot be declared both .virtual. and .constexpr." }
+ constexpr virtual void bar(); // { dg-error "13:member .bar. can be declared both .virtual. and .constexpr." }
/* { dg-begin-multiline-output "" }
constexpr virtual void bar();
~~~~~~~~~ ^~~~~~~
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