* parser.c (cp_parser_type_id_1): Allow 'auto' if -fconcepts.
(cp_parser_template_type_arg): Likewise.
(get_concept_from_constraint): Split out most logic to...
* constraint.cc (placeholder_extract_concept_and_args): ...here.
(equivalent_placeholder_constraints, hash_placeholder_constraint): New.
* cxx-pretty-print.c (pp_cxx_constrained_type_spec): New.
* cxx-pretty-print.h: Declare it.
* error.c (dump_type) [TEMPLATE_TYPE_PARM]: Call it.
* pt.c (is_auto_r, extract_autos_r, extract_autos, auto_hash): New.
(type_uses_auto): Use is_auto_r.
(do_auto_deduction): Handle multiple 'auto's if -fconcepts.
* typeck.c (structural_comptypes) [TEMPLATE_TYPE_PARM]: Compare
constraints.
From-SVN: r229629
2015-10-31 Jason Merrill <jason@redhat.com>
+ Implement multiple 'auto' feature from Concepts TS.
+ * parser.c (cp_parser_type_id_1): Allow 'auto' if -fconcepts.
+ (cp_parser_template_type_arg): Likewise.
+ (get_concept_from_constraint): Split out most logic to...
+ * constraint.cc (placeholder_extract_concept_and_args): ...here.
+ (equivalent_placeholder_constraints, hash_placeholder_constraint): New.
+ * cxx-pretty-print.c (pp_cxx_constrained_type_spec): New.
+ * cxx-pretty-print.h: Declare it.
+ * error.c (dump_type) [TEMPLATE_TYPE_PARM]: Call it.
+ * pt.c (is_auto_r, extract_autos_r, extract_autos, auto_hash): New.
+ (type_uses_auto): Use is_auto_r.
+ (do_auto_deduction): Handle multiple 'auto's if -fconcepts.
+ * typeck.c (structural_comptypes) [TEMPLATE_TYPE_PARM]: Compare
+ constraints.
+
* pt.c (for_each_template_parm_r): Use WALK_SUBTREE.
Return a meaningful value rather than error_mark_node.
(for_each_template_parm): Return a tree.
return decl;
}
+/* Given the predicate constraint T from a placeholder type, extract its
+ TMPL and ARGS. */
+
+void
+placeholder_extract_concept_and_args (tree t, tree &tmpl, tree &args)
+{
+ gcc_assert (TREE_CODE (t) == PRED_CONSTR);
+ t = PRED_CONSTR_EXPR (t);
+ gcc_assert (TREE_CODE (t) == CALL_EXPR
+ || TREE_CODE (t) == TEMPLATE_ID_EXPR
+ || VAR_P (t));
+
+ if (TREE_CODE (t) == CALL_EXPR)
+ t = CALL_EXPR_FN (t);
+ if (TREE_CODE (t) == TEMPLATE_ID_EXPR)
+ {
+ tmpl = TREE_OPERAND (t, 0);
+ if (TREE_CODE (tmpl) == OVERLOAD)
+ {
+ gcc_assert (OVL_CHAIN (tmpl) == NULL_TREE);
+ tmpl = OVL_FUNCTION (tmpl);
+ }
+ args = TREE_OPERAND (t, 1);
+ }
+ else if (DECL_P (t))
+ {
+ tmpl = DECL_TI_TEMPLATE (t);
+ args = DECL_TI_ARGS (t);
+ }
+ else
+ gcc_unreachable ();
+}
+
+/* Returns true iff the placeholders C1 and C2 are equivalent. C1
+ and C2 can be either PRED_CONSTR_EXPR or TEMPLATE_TYPE_PARM. */
+
+bool
+equivalent_placeholder_constraints (tree c1, tree c2)
+{
+ if (TREE_CODE (c1) == TEMPLATE_TYPE_PARM)
+ c1 = PLACEHOLDER_TYPE_CONSTRAINTS (c1);
+ if (TREE_CODE (c2) == TEMPLATE_TYPE_PARM)
+ c2 = PLACEHOLDER_TYPE_CONSTRAINTS (c2);
+
+ if (c1 == c2)
+ return true;
+ if (!c1 || !c2)
+ return false;
+
+ tree t1, t2, a1, a2;
+ placeholder_extract_concept_and_args (c1, t1, a1);
+ placeholder_extract_concept_and_args (c2, t2, a2);
+
+ if (t1 != t2)
+ return false;
+ int len = TREE_VEC_LENGTH (a1);
+ if (len != TREE_VEC_LENGTH (a2))
+ return false;
+ /* Skip the first argument to avoid infinite recursion on the
+ placeholder auto itself. */
+ for (int i = len-1; i > 0; --i)
+ if (!cp_tree_equal (TREE_VEC_ELT (a1, i),
+ TREE_VEC_ELT (a2, i)))
+ return false;
+ return true;
+}
+
+/* Return a hash value for the placeholder PRED_CONSTR C. */
+
+hashval_t
+hash_placeholder_constraint (tree c)
+{
+ tree t, a;
+ placeholder_extract_concept_and_args (c, t, a);
+
+ /* Like hash_tmpl_and_args, but skip the first argument. */
+ hashval_t val = iterative_hash_object (DECL_UID (t), 0);
+
+ for (int i = TREE_VEC_LENGTH (a)-1; i > 0; --i)
+ val = iterative_hash_template_arg (TREE_VEC_ELT (a, i), val);
+
+ return val;
+}
/*---------------------------------------------------------------------------
Constraint substitution
extern tree build_concept_check (tree, tree, tree = NULL_TREE);
extern tree build_constrained_parameter (tree, tree, tree = NULL_TREE);
extern tree make_constrained_auto (tree, tree);
+extern void placeholder_extract_concept_and_args (tree, tree&, tree&);
+extern bool equivalent_placeholder_constraints (tree, tree);
+extern hashval_t hash_placeholder_constraint (tree);
extern bool deduce_constrained_parameter (tree, tree&, tree&);
extern tree resolve_constraint_check (tree);
extern tree check_function_concept (tree);
pp_cxx_end_template_argument_list (pp);
}
+/* Print a constrained-type-specifier. */
+
+void
+pp_cxx_constrained_type_spec (cxx_pretty_printer *pp, tree c)
+{
+ tree t, a;
+ placeholder_extract_concept_and_args (c, t, a);
+ pp->id_expression (t);
+ if (TREE_VEC_LENGTH (a) > 1)
+ {
+ pp_cxx_begin_template_argument_list (pp);
+ tree args = make_tree_vec (TREE_VEC_LENGTH (a) - 1);
+ for (int i = TREE_VEC_LENGTH (a) - 1; i > 0; --i)
+ TREE_VEC_ELT (args, i-1) = TREE_VEC_ELT (a, i);
+ pp_cxx_template_argument_list (pp, args);
+ ggc_free (args);
+ pp_cxx_end_template_argument_list (pp);
+ }
+}
+
/*
template-declaration:
export(opt) template < template-parameter-list > declaration
void pp_cxx_conjunction (cxx_pretty_printer *, tree);
void pp_cxx_disjunction (cxx_pretty_printer *, tree);
void pp_cxx_constraint (cxx_pretty_printer *, tree);
+void pp_cxx_constrained_type_spec (cxx_pretty_printer *, tree);
#endif /* GCC_CXX_PRETTY_PRINT_H */
case TEMPLATE_TYPE_PARM:
pp_cxx_cv_qualifier_seq (pp, t);
- if (TYPE_IDENTIFIER (t))
+ if (tree c = PLACEHOLDER_TYPE_CONSTRAINTS (t))
+ pp_cxx_constrained_type_spec (pp, c);
+ else if (TYPE_IDENTIFIER (t))
pp_cxx_tree_identifier (pp, TYPE_IDENTIFIER (t));
else
pp_cxx_canonical_template_parameter
abstract_declarator = NULL;
if (type_specifier_seq.type
+ /* The concepts TS allows 'auto' as a type-id. */
+ && !flag_concepts
/* None of the valid uses of 'auto' in C++14 involve the type-id
nonterminal, but it is valid in a trailing-return-type. */
&& !(cxx_dialect >= cxx14 && is_trailing_return)
= G_("types may not be defined in template arguments");
r = cp_parser_type_id_1 (parser, true, false);
parser->type_definition_forbidden_message = saved_message;
- if (cxx_dialect >= cxx14 && type_uses_auto (r))
+ if (cxx_dialect >= cxx14 && !flag_concepts && type_uses_auto (r))
{
error ("invalid use of %<auto%> in template argument");
r = error_mark_node;
static tree
get_concept_from_constraint (tree t)
{
- gcc_assert (TREE_CODE (t) == PRED_CONSTR);
- t = PRED_CONSTR_EXPR (t);
- gcc_assert (TREE_CODE (t) == CALL_EXPR
- || TREE_CODE (t) == TEMPLATE_ID_EXPR
- || VAR_P (t));
-
- if (TREE_CODE (t) == TEMPLATE_ID_EXPR)
- return DECL_TEMPLATE_RESULT (TREE_OPERAND (t, 0));
- if (VAR_P (t))
- return DECL_TEMPLATE_RESULT (DECL_TI_TEMPLATE (t));
- else
- {
- tree fn = CALL_EXPR_FN (t);
- tree ovl = TREE_OPERAND (fn, 0);
- tree tmpl = OVL_FUNCTION (ovl);
- return DECL_TEMPLATE_RESULT (tmpl);
- }
+ tree tmpl, args;
+ placeholder_extract_concept_and_args (t, tmpl, args);
+ return DECL_TEMPLATE_RESULT (tmpl);
}
/* Add an implicit template type parameter to the CURRENT_TEMPLATE_PARMS
return tsubst (type, argvec, tf_warning_or_error, NULL_TREE);
}
+/* Hash traits for hashing possibly constrained 'auto'
+ TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
+
+struct auto_hash : default_hash_traits<tree>
+{
+ static inline hashval_t hash (tree);
+ static inline bool equal (tree, tree);
+};
+
+/* Hash the 'auto' T. */
+
+inline hashval_t
+auto_hash::hash (tree t)
+{
+ if (tree c = PLACEHOLDER_TYPE_CONSTRAINTS (t))
+ /* Matching constrained-type-specifiers denote the same template
+ parameter, so hash the constraint. */
+ return hash_placeholder_constraint (c);
+ else
+ /* But unconstrained autos are all separate, so just hash the pointer. */
+ return iterative_hash_object (t, 0);
+}
+
+/* Compare two 'auto's. */
+
+inline bool
+auto_hash::equal (tree t1, tree t2)
+{
+ if (t1 == t2)
+ return true;
+
+ tree c1 = PLACEHOLDER_TYPE_CONSTRAINTS (t1);
+ tree c2 = PLACEHOLDER_TYPE_CONSTRAINTS (t2);
+
+ /* Two unconstrained autos are distinct. */
+ if (!c1 || !c2)
+ return false;
+
+ return equivalent_placeholder_constraints (c1, c2);
+}
+
+/* for_each_template_parm callback for extract_autos: if t is a (possibly
+ constrained) auto, add it to the vector. */
+
+static int
+extract_autos_r (tree t, void *data)
+{
+ hash_table<auto_hash> &hash = *(hash_table<auto_hash>*)data;
+ if (is_auto_or_concept (t))
+ {
+ /* All the autos were built with index 0; fix that up now. */
+ tree *p = hash.find_slot (t, INSERT);
+ unsigned idx;
+ if (*p)
+ /* If this is a repeated constrained-type-specifier, use the index we
+ chose before. */
+ idx = TEMPLATE_PARM_IDX (TEMPLATE_TYPE_PARM_INDEX (*p));
+ else
+ {
+ /* Otherwise this is new, so use the current count. */
+ *p = t;
+ idx = hash.elements () - 1;
+ }
+ TEMPLATE_PARM_IDX (TEMPLATE_TYPE_PARM_INDEX (t)) = idx;
+ }
+
+ /* Always keep walking. */
+ return 0;
+}
+
+/* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
+ says they can appear anywhere in the type. */
+
+static tree
+extract_autos (tree type)
+{
+ hash_set<tree> visited;
+ hash_table<auto_hash> hash (2);
+
+ for_each_template_parm (type, extract_autos_r, &hash, &visited, true);
+
+ tree tree_vec = make_tree_vec (hash.elements());
+ for (hash_table<auto_hash>::iterator iter = hash.begin();
+ iter != hash.end(); ++iter)
+ {
+ tree elt = *iter;
+ unsigned i = TEMPLATE_PARM_IDX (TEMPLATE_TYPE_PARM_INDEX (elt));
+ TREE_VEC_ELT (tree_vec, i)
+ = build_tree_list (NULL_TREE, TYPE_NAME (elt));
+ }
+
+ return tree_vec;
+}
+
/* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
init = resolve_nondeduced_context (init);
- targs = make_tree_vec (1);
if (AUTO_IS_DECLTYPE (auto_node))
{
bool id = (DECL_P (init) || (TREE_CODE (init) == COMPONENT_REF
&& !REF_PARENTHESIZED_P (init)));
+ targs = make_tree_vec (1);
TREE_VEC_ELT (targs, 0)
= finish_decltype_type (init, id, tf_warning_or_error);
if (type != auto_node)
else
{
tree parms = build_tree_list (NULL_TREE, type);
- tree tparms = make_tree_vec (1);
- int val;
-
- TREE_VEC_ELT (tparms, 0)
- = build_tree_list (NULL_TREE, TYPE_NAME (auto_node));
- val = type_unification_real (tparms, targs, parms, &init, 1, 0,
- DEDUCE_CALL, LOOKUP_NORMAL,
- NULL, /*explain_p=*/false);
+ tree tparms;
+
+ if (flag_concepts)
+ tparms = extract_autos (type);
+ else
+ {
+ tparms = make_tree_vec (1);
+ TREE_VEC_ELT (tparms, 0)
+ = build_tree_list (NULL_TREE, TYPE_NAME (auto_node));
+ }
+
+ targs = make_tree_vec (TREE_VEC_LENGTH (tparms));
+ int val = type_unification_real (tparms, targs, parms, &init, 1, 0,
+ DEDUCE_CALL, LOOKUP_NORMAL,
+ NULL, /*explain_p=*/false);
if (val > 0)
{
if (processing_template_decl)
of each declared variable is determined as described above. If the
type deduced for the template parameter U is not the same in each
deduction, the program is ill-formed. */
- if (TREE_TYPE (auto_node)
+ if (!flag_concepts && TREE_TYPE (auto_node)
&& !same_type_p (TREE_TYPE (auto_node), TREE_VEC_ELT (targs, 0)))
{
if (cfun && auto_node == current_function_auto_return_pattern
auto_node, TREE_TYPE (auto_node), TREE_VEC_ELT (targs, 0));
return error_mark_node;
}
- if (context != adc_requirement)
+ if (!flag_concepts)
TREE_TYPE (auto_node) = TREE_VEC_ELT (targs, 0);
/* Check any placeholder constraints against the deduced type. */
return false;
}
+/* for_each_template_parm callback for type_uses_auto. */
+
+int
+is_auto_r (tree tp, void */*data*/)
+{
+ return is_auto_or_concept (tp);
+}
+
/* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
a use of `auto'. Returns NULL_TREE otherwise. */
tree
type_uses_auto (tree type)
{
- return find_type_usage (type, is_auto);
+ if (flag_concepts)
+ {
+ /* The Concepts TS allows multiple autos in one type-specifier; just
+ return the first one we find, do_auto_deduction will collect all of
+ them. */
+ if (uses_template_parms (type))
+ return for_each_template_parm (type, is_auto_r, /*data*/NULL,
+ /*visited*/NULL, /*nondeduced*/true);
+ else
+ return NULL_TREE;
+ }
+ else
+ return find_type_usage (type, is_auto);
}
/* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
template parameters set, they can't be equal. */
if (!comp_template_parms_position (t1, t2))
return false;
+ /* Constrained 'auto's are distinct from parms that don't have the same
+ constraints. */
+ if (!equivalent_placeholder_constraints (t1, t2))
+ return false;
break;
case TYPENAME_TYPE:
--- /dev/null
+// { dg-options "-std=c++1z" }
+
+template <class T1, class T2> class A { };
+
+A<int, int> a;
+A<double, float> a2;
+A<double, double> a22;
+
+A<auto, auto> b = a;
+A<auto, auto> b1 = a2;
+
+template <class T> concept bool C = __is_same_as (T, int);
+
+A<C,C> b2 = a;
+A<C,C> b3 = a2; // { dg-error "" }
+A<C,C> b32 = a22; // { dg-error "" }
+
+template <class T> concept bool C2() { return __is_enum (T); }
+
+enum E1 { };
+enum E2 { };
+
+A<E1,E1> a3;
+A<C2,C2> b4 = a3;
+
+A<E1,E2> a4;
+A<C2,C2> b5 = a4; // { dg-error "" }
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