cp-tree.h (AUTO_IS_DECLTYPE): New.

N3582
	* cp-tree.h (AUTO_IS_DECLTYPE): New.
	* parser.c (cp_parser_decltype): Handle decltype(auto).
	(cp_parser_type_id_1): Allow auto without a late-specified
	return in C++1y.
	(cp_parser_primary_expression): Use the return value of
	finish_parenthesized_expr.
	(cp_parser_transaction_expression): Likewise.
	* semantics.c (force_paren_expr): New.
	(finish_parenthesized_expr): Use it.
	* call.c (build_conditional_expr_1): Likewise.
	* pt.c (do_auto_deduction): Handle decltype(auto).
	(tsubst_copy): Handle PAREN_EXPR.
	(tsubst_copy_and_build): Likewise.
	* error.c (dump_expr): Handle PAREN_EXPR.
	* cxx-pretty-print.c (pp_cxx_expression): Likewise.
	* mangle.c (write_expression): Ignore PAREN_EXPR.

	* parser.c (cp_parser_decltype_expr): Split out...
	(cp_parser_decltype): ...from here.

From-SVN: r197248
This commit is contained in:
Jason Merrill 2013-03-29 15:51:36 -04:00 committed by Jason Merrill
parent 15914ac8b1
commit 10c6dc8e39
13 changed files with 227 additions and 28 deletions

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@ -1,5 +1,23 @@
2013-03-29 Jason Merrill <jason@redhat.com>
N3582
* cp-tree.h (AUTO_IS_DECLTYPE): New.
* parser.c (cp_parser_decltype): Handle decltype(auto).
(cp_parser_type_id_1): Allow auto without a late-specified
return in C++1y.
(cp_parser_primary_expression): Use the return value of
finish_parenthesized_expr.
(cp_parser_transaction_expression): Likewise.
* semantics.c (force_paren_expr): New.
(finish_parenthesized_expr): Use it.
* call.c (build_conditional_expr_1): Likewise.
* pt.c (do_auto_deduction): Handle decltype(auto).
(tsubst_copy): Handle PAREN_EXPR.
(tsubst_copy_and_build): Likewise.
* error.c (dump_expr): Handle PAREN_EXPR.
* cxx-pretty-print.c (pp_cxx_expression): Likewise.
* mangle.c (write_expression): Ignore PAREN_EXPR.
* parser.c (cp_parser_decltype_expr): Split out...
(cp_parser_decltype): ...from here.

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@ -4845,6 +4845,8 @@ build_conditional_expr_1 (tree arg1, tree arg2, tree arg3,
lvalue, we must add a NON_LVALUE_EXPR. */
result = rvalue (result);
}
else
result = force_paren_expr (result);
return result;
}

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@ -121,6 +121,7 @@ c-common.h, not after.
4: TYPE_HAS_NONTRIVIAL_DESTRUCTOR
5: CLASS_TYPE_P (in RECORD_TYPE and UNION_TYPE)
ENUM_FIXED_UNDERLYING_TYPE_P (in ENUMERAL_TYPE)
AUTO_IS_DECLTYPE (in TEMPLATE_TYPE_PARM)
6: TYPE_DEPENDENT_P_VALID
Usage of DECL_LANG_FLAG_?:
@ -4604,6 +4605,10 @@ enum overload_flags { NO_SPECIAL = 0, DTOR_FLAG, TYPENAME_FLAG };
#define TEMPLATE_TYPE_PARAMETER_PACK(NODE) \
(TEMPLATE_PARM_PARAMETER_PACK (TEMPLATE_TYPE_PARM_INDEX (NODE)))
/* True iff this TEMPLATE_TYPE_PARM represents decltype(auto). */
#define AUTO_IS_DECLTYPE(NODE) \
(TYPE_LANG_FLAG_5 (TEMPLATE_TYPE_PARM_CHECK (NODE)))
/* These constants can used as bit flags in the process of tree formatting.
TFF_PLAIN_IDENTIFIER: unqualified part of a name.
@ -5659,6 +5664,7 @@ extern tree finish_asm_stmt (int, tree, tree, tree, tree,
extern tree finish_label_stmt (tree);
extern void finish_label_decl (tree);
extern tree finish_parenthesized_expr (tree);
extern tree force_paren_expr (tree);
extern tree finish_non_static_data_member (tree, tree, tree);
extern tree begin_stmt_expr (void);
extern tree finish_stmt_expr_expr (tree, tree);

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@ -1167,6 +1167,12 @@ pp_cxx_expression (cxx_pretty_printer *pp, tree t)
pp_cxx_ws_string (pp, "<lambda>");
break;
case PAREN_EXPR:
pp_cxx_left_paren (pp);
pp_cxx_expression (pp, TREE_OPERAND (t, 0));
pp_cxx_right_paren (pp);
break;
default:
pp_c_expression (pp_c_base (pp), t);
break;

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@ -2506,6 +2506,12 @@ dump_expr (tree t, int flags)
pp_string (cxx_pp, M_("<lambda>"));
break;
case PAREN_EXPR:
pp_cxx_left_paren (cxx_pp);
dump_expr (TREE_OPERAND (t, 0), flags | TFF_EXPR_IN_PARENS);
pp_cxx_right_paren (cxx_pp);
break;
/* This list is incomplete, but should suffice for now.
It is very important that `sorry' does not call
`report_error_function'. That could cause an infinite loop. */

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@ -2555,6 +2555,8 @@ write_expression (tree expr)
is converted (via qualification conversions) to another
type. */
while (TREE_CODE (expr) == NOP_EXPR
/* Parentheses aren't mangled. */
|| code == PAREN_EXPR
|| TREE_CODE (expr) == NON_LVALUE_EXPR)
{
expr = TREE_OPERAND (expr, 0);

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@ -4106,7 +4106,7 @@ cp_parser_primary_expression (cp_parser *parser,
example, the expression is of the form `A::B', since
`&A::B' might be a pointer-to-member, but `&(A::B)' is
not. */
finish_parenthesized_expr (expr);
expr = finish_parenthesized_expr (expr);
/* DR 705: Wrapping an unqualified name in parentheses
suppresses arg-dependent lookup. We want to pass back
CP_ID_KIND_QUALIFIED for suppressing vtable lookup
@ -11399,7 +11399,9 @@ cp_parser_decltype_expr (cp_parser *parser,
/* Parse a `decltype' type. Returns the type.
simple-type-specifier:
decltype ( expression ) */
decltype ( expression )
C++14 proposal:
decltype ( auto ) */
static tree
cp_parser_decltype (cp_parser *parser)
@ -11427,6 +11429,18 @@ cp_parser_decltype (cp_parser *parser)
if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
return error_mark_node;
/* decltype (auto) */
if (cxx_dialect >= cxx1y
&& cp_lexer_next_token_is_keyword (parser->lexer, RID_AUTO))
{
cp_lexer_consume_token (parser->lexer);
if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
return error_mark_node;
expr = make_auto ();
AUTO_IS_DECLTYPE (expr) = true;
goto rewrite;
}
/* Types cannot be defined in a `decltype' expression. Save away the
old message. */
saved_message = parser->type_definition_forbidden_message;
@ -11485,6 +11499,7 @@ cp_parser_decltype (cp_parser *parser)
expr = finish_decltype_type (expr, id_expression_or_member_access_p,
tf_warning_or_error);
rewrite:
/* Replace the decltype with a CPP_DECLTYPE so we don't need to parse
it again. */
start_token->type = CPP_DECLTYPE;
@ -17207,6 +17222,7 @@ cp_parser_type_id_1 (cp_parser* parser, bool is_template_arg,
abstract_declarator = NULL;
if (type_specifier_seq.type
&& cxx_dialect < cxx1y
&& type_uses_auto (type_specifier_seq.type))
{
/* A type-id with type 'auto' is only ok if the abstract declarator
@ -28003,7 +28019,7 @@ cp_parser_transaction_expression (cp_parser *parser, enum rid keyword)
cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
expr = cp_parser_expression (parser, /*cast_p=*/false, NULL);
finish_parenthesized_expr (expr);
expr = finish_parenthesized_expr (expr);
cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
}

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@ -12303,6 +12303,7 @@ tsubst_copy (tree t, tree args, tsubst_flags_t complain, tree in_decl)
case TYPEID_EXPR:
case REALPART_EXPR:
case IMAGPART_EXPR:
case PAREN_EXPR:
return build1
(code, tsubst (TREE_TYPE (t), args, complain, in_decl),
tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl));
@ -14549,6 +14550,9 @@ tsubst_copy_and_build (tree t,
RETURN (tsubst_expr(t, args, complain, in_decl,
integral_constant_expression_p));
case PAREN_EXPR:
RETURN (finish_parenthesized_expr (RECUR (TREE_OPERAND (t, 0))));
default:
/* Handle Objective-C++ constructs, if appropriate. */
{
@ -20593,9 +20597,7 @@ listify_autos (tree type, tree auto_node)
tree
do_auto_deduction (tree type, tree init, tree auto_node)
{
tree parms, tparms, targs;
tree args[1];
int val;
tree targs;
if (init == error_mark_node)
return error_mark_node;
@ -20614,32 +20616,42 @@ do_auto_deduction (tree type, tree init, tree auto_node)
init = resolve_nondeduced_context (init);
parms = build_tree_list (NULL_TREE, type);
args[0] = init;
tparms = make_tree_vec (1);
targs = make_tree_vec (1);
TREE_VEC_ELT (tparms, 0)
= build_tree_list (NULL_TREE, TYPE_NAME (auto_node));
val = type_unification_real (tparms, targs, parms, args, 1, 0,
DEDUCE_CALL, LOOKUP_NORMAL,
/*explain_p=*/false);
if (val > 0)
if (AUTO_IS_DECLTYPE (auto_node))
{
if (processing_template_decl)
/* Try again at instantiation time. */
return type;
if (type && type != error_mark_node)
/* If type is error_mark_node a diagnostic must have been
emitted by now. Also, having a mention to '<type error>'
in the diagnostic is not really useful to the user. */
bool id = (DECL_P (init) || TREE_CODE (init) == COMPONENT_REF);
TREE_VEC_ELT (targs, 0)
= finish_decltype_type (init, id, tf_warning_or_error);
}
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,
/*explain_p=*/false);
if (val > 0)
{
if (cfun && auto_node == current_function_auto_return_pattern
&& LAMBDA_FUNCTION_P (current_function_decl))
error ("unable to deduce lambda return type from %qE", init);
else
error ("unable to deduce %qT from %qE", type, init);
if (processing_template_decl)
/* Try again at instantiation time. */
return type;
if (type && type != error_mark_node)
/* If type is error_mark_node a diagnostic must have been
emitted by now. Also, having a mention to '<type error>'
in the diagnostic is not really useful to the user. */
{
if (cfun && auto_node == current_function_auto_return_pattern
&& LAMBDA_FUNCTION_P (current_function_decl))
error ("unable to deduce lambda return type from %qE", init);
else
error ("unable to deduce %qT from %qE", type, init);
}
return error_mark_node;
}
return error_mark_node;
}
/* If the list of declarators contains more than one declarator, the type

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@ -1507,6 +1507,38 @@ finish_mem_initializers (tree mem_inits)
emit_mem_initializers (mem_inits);
}
/* Obfuscate EXPR if it looks like an id-expression or member access so
that the call to finish_decltype in do_auto_deduction will give the
right result. */
tree
force_paren_expr (tree expr)
{
/* This is only needed for decltype(auto) in C++14. */
if (cxx_dialect < cxx1y)
return expr;
if (!DECL_P (expr) && TREE_CODE (expr) != COMPONENT_REF
&& TREE_CODE (expr) != SCOPE_REF)
return expr;
if (processing_template_decl)
expr = build1 (PAREN_EXPR, TREE_TYPE (expr), expr);
else
{
cp_lvalue_kind kind = lvalue_kind (expr);
if ((kind & ~clk_class) != clk_none)
{
tree type = unlowered_expr_type (expr);
bool rval = !!(kind & clk_rvalueref);
type = cp_build_reference_type (type, rval);
expr = build_static_cast (type, expr, tf_warning_or_error);
}
}
return expr;
}
/* Finish a parenthesized expression EXPR. */
tree
@ -1525,6 +1557,8 @@ finish_parenthesized_expr (tree expr)
if (TREE_CODE (expr) == STRING_CST)
PAREN_STRING_LITERAL_P (expr) = 1;
expr = force_paren_expr (expr);
return expr;
}

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@ -0,0 +1,50 @@
// { dg-options "-std=c++1y -Wno-return-local-addr" }
template<class,class> struct same_type;
template<class T> struct same_type<T,T> {};
int& f();
int i;
decltype(auto) g() { return f(); }
decltype(auto) h1() { return i; }
decltype(auto) h2() { return (i); }
decltype(auto) h2a() { return 0,i; }
struct A { int i; };
A a;
decltype(auto) h3() { return a.i; }
decltype(auto) h4() { return (a.i); }
template <class T>
decltype(auto) h5(T t) { return t.i; }
template <class T>
decltype(auto) h6(T t) { return (t.i); }
int main()
{
decltype(auto) i = f();
same_type<decltype(i),int&>();
decltype(auto) i2 = i;
same_type<decltype(i2),int&>();
decltype(auto) i3 = ::i;
same_type<decltype(i3),int>();
decltype(auto) i4 = (::i);
same_type<decltype(i4),int&>();
decltype(auto) i5 = a.i;
same_type<decltype(i5),int>();
decltype(auto) i6 = (a.i);
same_type<decltype(i6),int&>();
decltype(auto) i7 = true ? ::i : ::i;
same_type<decltype(i7),int&>();
same_type<decltype(g()),int&>();
same_type<decltype(h1()),int>();
same_type<decltype(h2()),int&>();
same_type<decltype(h2a()),int&>();
same_type<decltype(h3()),int>();
same_type<decltype(h4()),int&>();
same_type<decltype(h5(a)),int>();
same_type<decltype(h6(a)),int&>();
}

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@ -0,0 +1,12 @@
// { dg-options -std=c++1y }
template<class,class> struct ST;
template<class T> struct ST<T,T> {};
int j;
auto x3 = []()->auto&& { return j; }; // OK: return type is int&
int main()
{
ST<decltype(x3()),int&>();
}

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@ -0,0 +1,22 @@
// { dg-options -std=c++1y }
// { dg-do run }
int c;
int d;
struct A
{
A() { ++c; }
A(const A&) { ++c; }
~A() { ++d; }
};
A g() { return A(); }
decltype(auto) f() { return g(); }
int main()
{
f();
if (c < 1 || c != d)
__builtin_abort ();
}

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@ -0,0 +1,13 @@
// Test that the parens don't show up in the mangling
// { dg-options "-std=c++1y -Wno-return-local-addr" }
// { dg-final { scan-assembler "_Z1gI1AEDTdtfp_1iET_" } }
struct A { int i; };
template <class T>
auto g(T t)->decltype((t.i)) { return t.i; }
int main()
{
g(A());
}