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PR c++/91360 - Implement C++20 P1143R2: constinit.

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* c-common.c (c_common_reswords): Add constinit and __constinit.
	(keyword_is_decl_specifier): Handle RID_CONSTINIT.
	* c-common.h (enum rid): Add RID_CONSTINIT, RID_FIRST_CXX20, and
	RID_LAST_CXX20.
	(D_CXX20): Define.
	* c-cppbuiltin.c (c_cpp_builtins): Define __cpp_constinit.
	* c-format.c (cxx_keywords): Add "constinit".
	* c.opt (Wc++2a-compat, Wc++20-compat): New options.

	* cp-tree.h (TINFO_VAR_DECLARED_CONSTINIT): Define.
	(LOOKUP_CONSTINIT): Define.
	(enum cp_decl_spec): Add ds_constinit.
	* decl.c (check_tag_decl): Give an error for constinit in type
	declarations.
	(check_initializer): Also check LOOKUP_CONSTINIT.
	(cp_finish_decl): Add checking for a constinit declaration.  Set
	TINFO_VAR_DECLARED_CONSTINIT.
	(grokdeclarator): Add checking for a declaration with the constinit
	specifier.
	* lex.c (init_reswords): Handle D_CXX20.
	* parser.c (cp_lexer_get_preprocessor_token): Pass a better location
	to warning_at.  Warn about C++20 keywords.
	(cp_keyword_starts_decl_specifier_p): Handle RID_CONSTINIT.
	(cp_parser_diagnose_invalid_type_name): Add an inform about constinit.
	(cp_parser_decomposition_declaration): Maybe pass LOOKUP_CONSTINIT to
	cp_finish_decl.
	(cp_parser_decl_specifier_seq): Handle RID_CONSTINIT.
	(cp_parser_init_declarator): Maybe pass LOOKUP_CONSTINIT to
	cp_finish_decl.
	(set_and_check_decl_spec_loc): Add "constinit".
	* pt.c (tsubst_decl): Set TINFO_VAR_DECLARED_CONSTINIT.
	(instantiate_decl): Maybe pass LOOKUP_CONSTINIT to cp_finish_decl.
	* typeck2.c (store_init_value): If a constinit variable wasn't
	initialized using a constant initializer, give an error.

	* doc/invoke.texi: Document -Wc++20-compat.

	* g++.dg/cpp2a/constinit1.C: New test.
	* g++.dg/cpp2a/constinit2.C: New test.
	* g++.dg/cpp2a/constinit3.C: New test.
	* g++.dg/cpp2a/constinit4.C: New test.
	* g++.dg/cpp2a/constinit5.C: New test.
	* g++.dg/cpp2a/constinit6.C: New test.
	* g++.dg/cpp2a/constinit7.C: New test.
	* g++.dg/cpp2a/constinit8.C: New test.
	* g++.dg/cpp2a/constinit9.C: New test.
	* g++.dg/cpp2a/constinit10.C: New test.
	* g++.dg/cpp2a/constinit11.C: New test.
	* g++.dg/cpp2a/constinit12.C: New test.

From-SVN: r275008
This commit is contained in:
Marek Polacek 2019-08-28 20:31:31 +00:00 committed by Marek Polacek
parent 6e12721acd
commit 4742dbe718
28 changed files with 556 additions and 17 deletions
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5
gcc/ChangeLog
View File

@ -1,3 +1,8 @@
2019-08-28 Marek Polacek <polacek@redhat.com>
PR c++/91360 - Implement C++20 P1143R2: constinit.
* doc/invoke.texi: Document -Wc++20-compat.
2019-08-28 Martin Sebor <msebor@redhat.com>
PR tree-optimization/91457

12
gcc/c-family/ChangeLog
View File

@ -1,3 +1,15 @@
2019-08-28 Marek Polacek <polacek@redhat.com>
PR c++/91360 - Implement C++20 P1143R2: constinit.
* c-common.c (c_common_reswords): Add constinit and __constinit.
(keyword_is_decl_specifier): Handle RID_CONSTINIT.
* c-common.h (enum rid): Add RID_CONSTINIT, RID_FIRST_CXX20, and
RID_LAST_CXX20.
(D_CXX20): Define.
* c-cppbuiltin.c (c_cpp_builtins): Define __cpp_constinit.
* c-format.c (cxx_keywords): Add "constinit".
* c.opt (Wc++2a-compat, Wc++20-compat): New options.
2019-08-27 Jakub Jelinek <jakub@redhat.com>
PR c++/91415

8
gcc/c-family/c-common.c
View File

@ -326,8 +326,9 @@ static bool nonnull_check_p (tree, unsigned HOST_WIDE_INT);
C --std=c89: D_C99 | D_CXXONLY | D_OBJC | D_CXX_OBJC
C --std=c99: D_CXXONLY | D_OBJC
ObjC is like C except that D_OBJC and D_CXX_OBJC are not set
C++ --std=c++98: D_CONLY | D_CXX11 | D_OBJC
C++ --std=c++11: D_CONLY | D_OBJC
C++ --std=c++98: D_CONLY | D_CXX11 | D_CXX20 | D_OBJC
C++ --std=c++11: D_CONLY | D_CXX20 | D_OBJC
C++ --std=c++2a: D_CONLY | D_OBJC
ObjC++ is like C++ except that D_OBJC is not set
If -fno-asm is used, D_ASM is added to the mask. If
@ -392,6 +393,7 @@ const struct c_common_resword c_common_reswords[] =
{ "__complex__", RID_COMPLEX, 0 },
{ "__const", RID_CONST, 0 },
{ "__const__", RID_CONST, 0 },
{ "__constinit", RID_CONSTINIT, D_CXXONLY },
{ "__decltype", RID_DECLTYPE, D_CXXONLY },
{ "__direct_bases", RID_DIRECT_BASES, D_CXXONLY },
{ "__extension__", RID_EXTENSION, 0 },
@ -462,6 +464,7 @@ const struct c_common_resword c_common_reswords[] =
{ "class", RID_CLASS, D_CXX_OBJC | D_CXXWARN },
{ "const", RID_CONST, 0 },
{ "constexpr", RID_CONSTEXPR, D_CXXONLY | D_CXX11 | D_CXXWARN },
{ "constinit", RID_CONSTINIT, D_CXXONLY | D_CXX20 | D_CXXWARN },
{ "const_cast", RID_CONSTCAST, D_CXXONLY | D_CXXWARN },
{ "continue", RID_CONTINUE, 0 },
{ "decltype", RID_DECLTYPE, D_CXXONLY | D_CXX11 | D_CXXWARN },
@ -7927,6 +7930,7 @@ keyword_is_decl_specifier (enum rid keyword)
case RID_TYPEDEF:
case RID_FRIEND:
case RID_CONSTEXPR:
case RID_CONSTINIT:
return true;
default:
return false;

6
gcc/c-family/c-common.h
View File

@ -180,6 +180,9 @@ enum rid
/* C++11 */
RID_CONSTEXPR, RID_DECLTYPE, RID_NOEXCEPT, RID_NULLPTR, RID_STATIC_ASSERT,
/* C++20 */
RID_CONSTINIT,
/* char8_t */
RID_CHAR8,
@ -250,6 +253,8 @@ enum rid
RID_FIRST_CXX11 = RID_CONSTEXPR,
RID_LAST_CXX11 = RID_STATIC_ASSERT,
RID_FIRST_CXX20 = RID_CONSTINIT,
RID_LAST_CXX20 = RID_CONSTINIT,
RID_FIRST_AT = RID_AT_ENCODE,
RID_LAST_AT = RID_AT_IMPLEMENTATION,
RID_FIRST_PQ = RID_IN,
@ -427,6 +432,7 @@ extern machine_mode c_default_pointer_mode;
#define D_CXX_CONCEPTS 0x0400 /* In C++, only with concepts. */
#define D_TRANSMEM 0X0800 /* C++ transactional memory TS. */
#define D_CXX_CHAR8_T 0X1000 /* In C++, only with -fchar8_t. */
#define D_CXX20 0x2000 /* In C++, C++20 only. */
#define D_CXX_CONCEPTS_FLAGS D_CXXONLY | D_CXX_CONCEPTS
#define D_CXX_CHAR8_T_FLAGS D_CXXONLY | D_CXX_CHAR8_T

1
gcc/c-family/c-cppbuiltin.c
View File

@ -986,6 +986,7 @@ c_cpp_builtins (cpp_reader *pfile)
{
/* Set feature test macros for C++2a. */
cpp_define (pfile, "__cpp_conditional_explicit=201806");
cpp_define (pfile, "__cpp_constinit=201907");
cpp_define (pfile, "__cpp_nontype_template_parameter_class=201806");
cpp_define (pfile, "__cpp_impl_destroying_delete=201806");
}

1
gcc/c-family/c-format.c
View File

@ -2958,6 +2958,7 @@ static const token_t cxx_keywords[] =
NAME ("catch", NULL),
NAME ("constexpr if", NULL),
NAME ("constexpr", NULL),
NAME ("constinit", NULL),
NAME ("consteval", NULL),
NAME ("decltype", NULL),
NAME ("nullptr", NULL),

7
gcc/c-family/c.opt
View File

@ -400,6 +400,13 @@ Wc++17-compat
C++ ObjC++ Var(warn_cxx17_compat) Warning LangEnabledBy(C++ ObjC++,Wall)
Warn about C++ constructs whose meaning differs between ISO C++ 2014 and ISO C++ 2017.
Wc++2a-compat
C++ ObjC++ Warning Alias(Wc++20-compat) Undocumented
Wc++20-compat
C++ ObjC++ Var(warn_cxx20_compat) Warning LangEnabledBy(C++ ObjC++,Wall)
Warn about C++ constructs whose meaning differs between ISO C++ 2017 and ISO C++ 2020.
Wcast-function-type
C ObjC C++ ObjC++ Var(warn_cast_function_type) Warning EnabledBy(Wextra)
Warn about casts between incompatible function types.

29
gcc/cp/ChangeLog
View File

@ -1,3 +1,32 @@
2019-08-28 Marek Polacek <polacek@redhat.com>
PR c++/91360 - Implement C++20 P1143R2: constinit.
* cp-tree.h (TINFO_VAR_DECLARED_CONSTINIT): Define.
(LOOKUP_CONSTINIT): Define.
(enum cp_decl_spec): Add ds_constinit.
* decl.c (check_tag_decl): Give an error for constinit in type
declarations.
(check_initializer): Also check LOOKUP_CONSTINIT.
(cp_finish_decl): Add checking for a constinit declaration. Set
TINFO_VAR_DECLARED_CONSTINIT.
(grokdeclarator): Add checking for a declaration with the constinit
specifier.
* lex.c (init_reswords): Handle D_CXX20.
* parser.c (cp_lexer_get_preprocessor_token): Pass a better location
to warning_at. Warn about C++20 keywords.
(cp_keyword_starts_decl_specifier_p): Handle RID_CONSTINIT.
(cp_parser_diagnose_invalid_type_name): Add an inform about constinit.
(cp_parser_decomposition_declaration): Maybe pass LOOKUP_CONSTINIT to
cp_finish_decl.
(cp_parser_decl_specifier_seq): Handle RID_CONSTINIT.
(cp_parser_init_declarator): Maybe pass LOOKUP_CONSTINIT to
cp_finish_decl.
(set_and_check_decl_spec_loc): Add "constinit".
* pt.c (tsubst_decl): Set TINFO_VAR_DECLARED_CONSTINIT.
(instantiate_decl): Maybe pass LOOKUP_CONSTINIT to cp_finish_decl.
* typeck2.c (store_init_value): If a constinit variable wasn't
initialized using a constant initializer, give an error.
2019-08-28 Nathan Sidwell <nathan@acm.org>
PR c++/90613

9
gcc/cp/cp-tree.h
View File

@ -443,6 +443,7 @@ extern GTY(()) tree cp_global_trees[CPTI_MAX];
SWITCH_STMT_NO_BREAK_P (in SWITCH_STMT)
LAMBDA_EXPR_CAPTURE_OPTIMIZED (in LAMBDA_EXPR)
IMPLICIT_CONV_EXPR_BRACED_INIT (in IMPLICIT_CONV_EXPR)
TINFO_VAR_DECLARED_CONSTINIT (in TEMPLATE_INFO)
3: (TREE_REFERENCE_EXPR) (in NON_LVALUE_EXPR) (commented-out).
ICS_BAD_FLAG (in _CONV)
FN_TRY_BLOCK_P (in TRY_BLOCK)
@ -1435,6 +1436,11 @@ typedef struct qualified_typedef_usage_s qualified_typedef_usage_t;
#define TINFO_USED_TEMPLATE_ID(NODE) \
(TREE_LANG_FLAG_1 (TEMPLATE_INFO_CHECK (NODE)))
/* Non-zero if this variable template specialization was declared with the
`constinit' specifier. */
#define TINFO_VAR_DECLARED_CONSTINIT(NODE) \
(TREE_LANG_FLAG_2 (TEMPLATE_INFO_CHECK (NODE)))
struct GTY(()) tree_template_info {
struct tree_base base;
tree tmpl;
@ -5502,6 +5508,8 @@ enum overload_flags { NO_SPECIAL = 0, DTOR_FLAG, TYPENAME_FLAG };
#define LOOKUP_DELEGATING_CONS (LOOKUP_NO_NON_INTEGRAL << 1)
/* Allow initialization of a flexible array members. */
#define LOOKUP_ALLOW_FLEXARRAY_INIT (LOOKUP_DELEGATING_CONS << 1)
/* Require constant initialization of a non-constant variable. */
#define LOOKUP_CONSTINIT (LOOKUP_ALLOW_FLEXARRAY_INIT << 1)
#define LOOKUP_NAMESPACES_ONLY(F) \
(((F) & LOOKUP_PREFER_NAMESPACES) && !((F) & LOOKUP_PREFER_TYPES))
@ -5815,6 +5823,7 @@ enum cp_decl_spec {
ds_alias,
ds_constexpr,
ds_complex,
ds_constinit,
ds_thread,
ds_type_spec,
ds_redefined_builtin_type_spec,

71
gcc/cp/decl.c
View File

@ -4962,6 +4962,9 @@ check_tag_decl (cp_decl_specifier_seq *declspecs,
else if (decl_spec_seq_has_spec_p (declspecs, ds_constexpr))
error_at (declspecs->locations[ds_constexpr],
"%<constexpr%> cannot be used for type declarations");
else if (decl_spec_seq_has_spec_p (declspecs, ds_constinit))
error_at (declspecs->locations[ds_constinit],
"%<constinit%> cannot be used for type declarations");
}
if (declspecs->attributes && warn_attributes && declared_type)
@ -6595,11 +6598,12 @@ check_initializer (tree decl, tree init, int flags, vec<tree, va_gc> **cleanups)
about aggregate initialization of non-aggregate classes. */
flags |= LOOKUP_ALREADY_DIGESTED;
}
else if (DECL_DECLARED_CONSTEXPR_P (decl))
else if (DECL_DECLARED_CONSTEXPR_P (decl)
|| (flags & LOOKUP_CONSTINIT))
{
/* Declared constexpr, but no suitable initializer; massage
init appropriately so we can pass it into store_init_value
for the error. */
/* Declared constexpr or constinit, but no suitable initializer;
massage init appropriately so we can pass it into
store_init_value for the error. */
if (CLASS_TYPE_P (type)
&& (!init || TREE_CODE (init) == TREE_LIST))
{
@ -7162,6 +7166,10 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
DECL_INITIAL (decl) = NULL_TREE;
}
/* Handle `constinit' on variable templates. */
if (flags & LOOKUP_CONSTINIT)
TINFO_VAR_DECLARED_CONSTINIT (DECL_TEMPLATE_INFO (decl)) = true;
/* Generally, initializers in templates are expanded when the
template is instantiated. But, if DECL is a variable constant
then it can be used in future constant expressions, so its value
@ -7253,6 +7261,18 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
if (VAR_P (decl))
{
duration_kind dk = decl_storage_duration (decl);
/* [dcl.constinit]/1 "The constinit specifier shall be applied
only to a declaration of a variable with static or thread storage
duration." */
if ((flags & LOOKUP_CONSTINIT)
&& !(dk == dk_thread || dk == dk_static))
{
error ("%<constinit%> can only be applied to a variable with static "
"or thread storage duration");
return;
}
/* If this is a local variable that will need a mangled name,
register it now. We must do this before processing the
initializer for the variable, since the initialization might
@ -10477,6 +10497,7 @@ grokdeclarator (const cp_declarator *declarator,
bool template_parm_flag = false;
bool typedef_p = decl_spec_seq_has_spec_p (declspecs, ds_typedef);
bool constexpr_p = decl_spec_seq_has_spec_p (declspecs, ds_constexpr);
bool constinit_p = decl_spec_seq_has_spec_p (declspecs, ds_constinit);
bool late_return_type_p = false;
bool array_parameter_p = false;
location_t saved_loc = input_location;
@ -10763,6 +10784,24 @@ grokdeclarator (const cp_declarator *declarator,
return error_mark_node;
}
if (constinit_p && typedef_p)
{
error_at (declspecs->locations[ds_constinit],
"%<constinit%> cannot appear in a typedef declaration");
return error_mark_node;
}
/* [dcl.spec]/2 "At most one of the constexpr, consteval, and constinit
keywords shall appear in a decl-specifier-seq." */
if (constinit_p && constexpr_p)
{
error_at (min_location (declspecs->locations[ds_constinit],
declspecs->locations[ds_constexpr]),
"can use at most one of the %<constinit%> and %<constexpr%> "
"specifiers");
return error_mark_node;
}
/* If there were multiple types specified in the decl-specifier-seq,
issue an error message. */
if (declspecs->multiple_types_p)
@ -11155,6 +11194,12 @@ grokdeclarator (const cp_declarator *declarator,
"a parameter cannot be declared %<constexpr%>");
constexpr_p = 0;
}
else if (constinit_p)
{
error_at (declspecs->locations[ds_constinit],
"a parameter cannot be declared %<constinit%>");
constexpr_p = 0;
}
}
/* Give error if `virtual' is used outside of class declaration. */
@ -11597,6 +11642,13 @@ grokdeclarator (const cp_declarator *declarator,
"an array", name);
return error_mark_node;
}
if (constinit_p)
{
error_at (declspecs->locations[ds_constinit],
"%<constinit%> on function return type is not "
"allowed");
return error_mark_node;
}
if (ctype == NULL_TREE
&& decl_context == FIELD
@ -12794,10 +12846,17 @@ grokdeclarator (const cp_declarator *declarator,
else if (constexpr_p)
{
error_at (declspecs->locations[ds_constexpr],
"non-static data member %qE declared %<constexpr%>",
unqualified_id);
"non-static data member %qE declared "
"%<constexpr%>", unqualified_id);
constexpr_p = false;
}
else if (constinit_p)
{
error_at (declspecs->locations[ds_constinit],
"non-static data member %qE declared "
"%<constinit%>", unqualified_id);
constinit_p = false;
}
decl = build_decl (id_loc, FIELD_DECL, unqualified_id, type);
DECL_NONADDRESSABLE_P (decl) = bitfield;
if (bitfield && !unqualified_id)

2
gcc/cp/lex.c
View File

@ -229,6 +229,8 @@ init_reswords (void)
if (cxx_dialect < cxx11)
mask |= D_CXX11;
if (cxx_dialect < cxx2a)
mask |= D_CXX20;
if (!flag_concepts)
mask |= D_CXX_CONCEPTS;
if (!flag_tm)

44
gcc/cp/parser.c
View File

@ -834,14 +834,28 @@ cp_lexer_get_preprocessor_token (cp_lexer *lexer, cp_token *token)
{
/* Warn about the C++0x keyword (but still treat it as
an identifier). */
warning (OPT_Wc__11_compat,
"identifier %qE is a keyword in C++11",
token->u.value);
warning_at (token->location, OPT_Wc__11_compat,
"identifier %qE is a keyword in C++11",
token->u.value);
/* Clear out the C_RID_CODE so we don't warn about this
particular identifier-turned-keyword again. */
C_SET_RID_CODE (token->u.value, RID_MAX);
}
if (warn_cxx20_compat
&& C_RID_CODE (token->u.value) >= RID_FIRST_CXX20
&& C_RID_CODE (token->u.value) <= RID_LAST_CXX20)
{
/* Warn about the C++20 keyword (but still treat it as
an identifier). */
warning_at (token->location, OPT_Wc__20_compat,
"identifier %qE is a keyword in C++20",
token->u.value);
/* Clear out the C_RID_CODE so we don't warn about this
particular identifier-turned-keyword again. */
C_SET_RID_CODE (token->u.value, RID_MAX);
}
token->keyword = RID_MAX;
}
@ -986,6 +1000,7 @@ cp_keyword_starts_decl_specifier_p (enum rid keyword)
case RID_DECLTYPE:
case RID_UNDERLYING_TYPE:
case RID_CONSTEXPR:
case RID_CONSTINIT:
return true;
default:
@ -3353,6 +3368,9 @@ cp_parser_diagnose_invalid_type_name (cp_parser *parser, tree id,
&& id_equal (id, "thread_local"))
inform (location, "C++11 %<thread_local%> only available with "
"%<-std=c++11%> or %<-std=gnu++11%>");
else if (cxx_dialect < cxx2a && id == ridpointers[(int)RID_CONSTINIT])
inform (location, "C++20 %<constinit%> only available with "
"%<-std=c++2a%> or %<-std=gnu++2a%>");
else if (!flag_concepts && id == ridpointers[(int)RID_CONCEPT])
inform (location, "%<concept%> only available with %<-fconcepts%>");
else if (processing_template_decl && current_class_type
@ -13839,9 +13857,12 @@ cp_parser_decomposition_declaration (cp_parser *parser,
if (decl != error_mark_node)
{
int flags = (decl_spec_seq_has_spec_p (decl_specifiers, ds_constinit)
? LOOKUP_CONSTINIT : 0);
cp_maybe_mangle_decomp (decl, prev, v.length ());
cp_finish_decl (decl, initializer, non_constant_p, NULL_TREE,
is_direct_init ? LOOKUP_NORMAL : LOOKUP_IMPLICIT);
(is_direct_init ? LOOKUP_NORMAL : LOOKUP_IMPLICIT)
| flags);
cp_finish_decomp (decl, prev, v.length ());
}
}
@ -13993,7 +14014,8 @@ cp_parser_decl_specifier_seq (cp_parser* parser,
{
/* decl-specifier:
friend
constexpr */
constexpr
constinit */
case RID_FRIEND:
if (!at_class_scope_p ())
{
@ -14015,6 +14037,11 @@ cp_parser_decl_specifier_seq (cp_parser* parser,
cp_lexer_consume_token (parser->lexer);
break;
case RID_CONSTINIT:
ds = ds_constinit;
cp_lexer_consume_token (parser->lexer);
break;
case RID_CONCEPT:
ds = ds_concept;
cp_lexer_consume_token (parser->lexer);
@ -20532,6 +20559,8 @@ cp_parser_init_declarator (cp_parser* parser,
declarations. */
if (!member_p && decl && decl != error_mark_node && !range_for_decl_p)
{
int cf = (decl_spec_seq_has_spec_p (decl_specifiers, ds_constinit)
? LOOKUP_CONSTINIT : 0);
cp_finish_decl (decl,
initializer, !is_non_constant_init,
asm_specification,
@ -20540,7 +20569,7 @@ cp_parser_init_declarator (cp_parser* parser,
`explicit' constructor is OK. Otherwise, an
`explicit' constructor cannot be used. */
((is_direct_init || !is_initialized)
? LOOKUP_NORMAL : LOOKUP_IMPLICIT));
? LOOKUP_NORMAL : LOOKUP_IMPLICIT) | cf);
}
else if ((cxx_dialect != cxx98) && friend_p
&& decl && TREE_CODE (decl) == FUNCTION_DECL)
@ -29470,7 +29499,8 @@ set_and_check_decl_spec_loc (cp_decl_specifier_seq *decl_specs,
"typedef",
"using",
"constexpr",
"__complex"
"__complex",
"constinit"
};
gcc_rich_location richloc (location);
richloc.add_fixit_remove ();

8
gcc/cp/pt.c
View File

@ -13955,6 +13955,10 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain)
DECL_TEMPLATE_INFO (r) = build_template_info (tmpl, argvec);
SET_DECL_IMPLICIT_INSTANTIATION (r);
/* Remember whether we require constant initialization of
a non-constant template variable. */
TINFO_VAR_DECLARED_CONSTINIT (DECL_TEMPLATE_INFO (r))
= TINFO_VAR_DECLARED_CONSTINIT (DECL_TEMPLATE_INFO (t));
if (!error_operand_p (r) || (complain & tf_error))
register_specialization (r, gen_tmpl, argvec, false, hash);
}
@ -24744,7 +24748,9 @@ instantiate_decl (tree d, bool defer_ok, bool expl_inst_class_mem_p)
push_nested_class (DECL_CONTEXT (d));
const_init = DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (code_pattern);
cp_finish_decl (d, init, const_init, NULL_TREE, 0);
int flags = (TINFO_VAR_DECLARED_CONSTINIT (DECL_TEMPLATE_INFO (d))
? LOOKUP_CONSTINIT : 0);
cp_finish_decl (d, init, const_init, NULL_TREE, flags);
if (enter_context)
pop_nested_class ();

17
gcc/cp/typeck2.c
View File

@ -885,7 +885,22 @@ store_init_value (tree decl, tree init, vec<tree, va_gc>** cleanups, int flags)
if (!TYPE_REF_P (type))
TREE_CONSTANT (decl) = const_init && decl_maybe_constant_var_p (decl);
if (!const_init)
value = oldval;
{
/* [dcl.constinit]/2 "If a variable declared with the constinit
specifier has dynamic initialization, the program is
ill-formed." */
if (flags & LOOKUP_CONSTINIT)
{
error_at (location_of (decl),
"%<constinit%> variable %qD does not have a constant "
"initializer", decl);
if (require_constant_expression (value))
cxx_constant_init (value, decl);
value = error_mark_node;
}
else
value = oldval;
}
}
value = cp_fully_fold_init (value);

7
gcc/doc/invoke.texi
View File

@ -295,6 +295,7 @@ Objective-C and Objective-C++ Dialects}.
-Wno-builtin-declaration-mismatch @gol
-Wno-builtin-macro-redefined -Wc90-c99-compat -Wc99-c11-compat @gol
-Wc++-compat -Wc++11-compat -Wc++14-compat -Wc++17-compat @gol
-Wc++20-compat @gol
-Wcast-align -Wcast-align=strict -Wcast-function-type -Wcast-qual @gol
-Wchar-subscripts -Wcatch-value -Wcatch-value=@var{n} @gol
-Wclobbered -Wcomment -Wconditionally-supported @gol
@ -6792,6 +6793,12 @@ and ISO C++ 2014. This warning is enabled by @option{-Wall}.
Warn about C++ constructs whose meaning differs between ISO C++ 2014
and ISO C++ 2017. This warning is enabled by @option{-Wall}.
@item -Wc++20-compat @r{(C++ and Objective-C++ only)}
@opindex Wc++20-compat
@opindex Wno-c++20-compat
Warn about C++ constructs whose meaning differs between ISO C++ 2017
and ISO C++ 2020. This warning is enabled by @option{-Wall}.
@item -Wcast-qual
@opindex Wcast-qual
@opindex Wno-cast-qual

16
gcc/testsuite/ChangeLog
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@ -1,3 +1,19 @@
2019-08-28 Marek Polacek <polacek@redhat.com>
PR c++/91360 - Implement C++20 P1143R2: constinit.
* g++.dg/cpp2a/constinit1.C: New test.
* g++.dg/cpp2a/constinit2.C: New test.
* g++.dg/cpp2a/constinit3.C: New test.
* g++.dg/cpp2a/constinit4.C: New test.
* g++.dg/cpp2a/constinit5.C: New test.
* g++.dg/cpp2a/constinit6.C: New test.
* g++.dg/cpp2a/constinit7.C: New test.
* g++.dg/cpp2a/constinit8.C: New test.
* g++.dg/cpp2a/constinit9.C: New test.
* g++.dg/cpp2a/constinit10.C: New test.
* g++.dg/cpp2a/constinit11.C: New test.
* g++.dg/cpp2a/constinit12.C: New test.
2019-08-28 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/91565

38
gcc/testsuite/g++.dg/cpp2a/constinit1.C Normal file
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@ -0,0 +1,38 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do compile { target c++2a } }
// Test basic usage of 'constinit'.
const char *g() { return "dynamic init"; }
constexpr const char *f(bool p) { return p ? "constant init" : g(); } // { dg-error "call to non-.constexpr. function" }
constinit const char *c = f(true);
constinit const char *d = f(false); // { dg-error "variable .d. does not have a constant initializer" }
// { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-1 }
static constinit const char *e = f(true);
constexpr int foo(int x) { return x; }
constinit int i = foo(42);
constinit int j // { dg-error "variable .j. does not have a constant initializer" }
= foo(i); // { dg-error "not usable in a constant expression" }
int y = 42;
constinit int x // { dg-error "variable .x. does not have a constant initializer" }
= y; // { dg-error "not usable in a constant expression" }
constinit int z;
const constinit unsigned cst = 1u;
void
fn ()
{
static constinit int m = foo(42);
static constinit int n // { dg-error "variable .n. does not have a constant initializer" }
= foo(m); // { dg-error "not usable in a constant expression" }
// Make sure we can still modify constinit variables.
c = "foo";
i = 10;
m = 90;
// ... unless they're 'const'.
cst *= 2; // { dg-error "assignment of read-only variable" }
}

26
gcc/testsuite/g++.dg/cpp2a/constinit10.C Normal file
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@ -0,0 +1,26 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do compile { target c++2a } }
// From PR83428.
struct S1
{
constexpr S1 ();
int m_i;
};
struct alignas(64) S2
{
constexpr S2 ()
: m_tabS1()
{}
S1 m_tabS1[7];
};
constinit S2 objX; // { dg-error ".constinit. variable .objX. does not have a constant initializer" }
// { dg-error "used before its definition" "" { target *-*-* } .-1 }
// // { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-2 }
constexpr S1::S1 ()
: m_i(14)
{}

79
gcc/testsuite/g++.dg/cpp2a/constinit11.C Normal file
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@ -0,0 +1,79 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do compile { target c++2a } }
int foo ();
constexpr int constfoo () { return 42; }
int gl = 42;
struct nonliteral {
int m;
nonliteral() : m() { }
nonliteral(int n) : m(n) { }
~nonliteral() {}
};
struct literal {
int m;
constexpr literal() : m() { }
constexpr literal(int n) : m(n) { }
};
struct pod {
int m;
};
struct S {
static constinit pod p;
static constinit pod pc;
static const constinit nonliteral n;
};
struct W {
int w = 42;
};
constinit W w;
constinit const int &r1 = gl;
constinit thread_local const int &r2 = gl;
constinit const int &r3 // { dg-error "variable .r3. does not have a constant initializer" }
= foo (); // { dg-error "call to non-.constexpr. function" }
constinit const literal &r4 = 42;
constinit const nonliteral &r5 // { dg-error "variable .r5. does not have a constant initializer" }
= 42; // { dg-error "call to non-.constexpr. function" }
constinit const int &r6 = nonliteral(2).m; // { dg-error "variable .r6. does not have a constant initializer|call to non-.constexpr. function" }
constinit pod p1;
constinit pod p2 = { 42 };
constinit pod p3 = { constfoo() };
constinit pod p4 = { foo() }; // { dg-error "variable .p4. does not have a constant initializer|call to non-.constexpr. function" }
constexpr literal lit;
constinit literal l1 = lit;
constinit literal l2 = 42;
constinit literal l3 = constfoo();
constinit literal l4 = foo(); // { dg-error "variable .l4. does not have a constant initializer|call to non-.constexpr. function" }
constinit literal l5 = {};
constinit literal l6{};
constinit thread_local literal l7 = lit;
constinit thread_local literal l8 = 42;
constinit thread_local literal l9 = constfoo();
constinit thread_local literal l10 = foo(); // { dg-error "variable .l10. does not have a constant initializer|call to non-.constexpr. function" }
constinit thread_local literal l11{};
pod S::p;
constinit pod S::pc(S::p); // { dg-error "variable .S::pc. does not have a constant initializer|not usable" }
constinit const nonliteral S::n(42); // { dg-error "variable .S::n. does not have a constant initializer|call to non-.constexpr. function" }
constinit int n1 = nonliteral{42}.m; // { dg-error "variable .n1. does not have a constant initializer|temporary of non-literal type" }
constinit int n2 = literal{42}.m;
void
fn1 ()
{
const int c = 42;
static constinit const int &l // { dg-error "variable .l. does not have a constant initializer" }
= c; // { dg-error "not a constant" }
static const int &l2 = 10;
static const int &l3 = gl;
}

14
gcc/testsuite/g++.dg/cpp2a/constinit12.C Normal file
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@ -0,0 +1,14 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do compile { target c++2a } }
struct S {
S(int) { }
};
template <class T>
struct U {
T m;
constexpr U(int i) : m(i) { } // { dg-error "call to non-.constexpr. function" }
};
constinit U<S> u(42); // { dg-error "does not have a constant initializer|called in a constant expression" }

14
gcc/testsuite/g++.dg/cpp2a/constinit2.C Normal file
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@ -0,0 +1,14 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do compile { target c++11 } }
// Test that 'constinit' isn't recognized pre-C++2a, but '__constinit' is.
constinit int g = 42; // { dg-error ".constinit. does not name a type" "" { target c++17_down } }
__constinit int g2 = 42;
static __constinit int g3 = 42;
void
fn ()
{
static constinit int x = 69; // { dg-error ".constinit. does not name a type" "" { target c++17_down } }
static __constinit int x2 = 69;
}

58
gcc/testsuite/g++.dg/cpp2a/constinit3.C Normal file
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@ -0,0 +1,58 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do compile { target c++2a } }
constinit constinit int v1; // { dg-error "duplicate .constinit." }
constexpr constinit int v2 = 1; // { dg-error "can use at most one of the .constinit. and .constexpr. specifiers" }
constinit constexpr int v3 = 1; // { dg-error "an use at most one of the .constinit. and .constexpr. specifiers" }
extern static constinit int v4; // { dg-error "conflicting specifiers" }
extern thread_local constinit int v5;
extern constinit int v6;
constinit typedef int T; // { dg-error ".constinit. cannot appear in a typedef declaration" }
struct S2 {
constinit int m1; // { dg-error "non-static data member .m1. declared .constinit." }
constinit unsigned int b : 32; // { dg-error " non-static data member .b. declared .constinit." }
};
struct S3 {
constinit S3() {} // { dg-error ".constinit. on function return type is not allowed" }
constinit ~S3() {} // { dg-error ".constinit. on function return type is not allowed" }
};
constinit struct S4 { // { dg-error ".constinit. cannot be used for type declarations" }
};
template<constinit int I> // { dg-error "a parameter cannot be declared .constinit." }
struct X { };
int
fn1 ()
{
// Not static storage
constinit int a1 = 42; // { dg-error ".constinit. can only be applied to a variable with static or thread storage" }
constinit int a2 = 42; // { dg-error ".constinit. can only be applied to a variable with static or thread storage" }
extern constinit int e1;
return 0;
}
constinit int // { dg-error ".constinit. on function return type is not allowed" }
fn3 ()
{
}
void
fn2 (int i, constinit int p) // { dg-error "a parameter cannot be declared .constinit." }
{
constinit auto l = [i](){ return i; }; // { dg-error ".constinit. can only be applied to a variable with static or thread storage" }
}
struct B { int d; };
void
fn3 (B b)
{
constinit auto [ a ] = b; // { dg-error ".constinit. can only be applied to a variable with static or thread storage" }
}

16
gcc/testsuite/g++.dg/cpp2a/constinit4.C Normal file
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@ -0,0 +1,16 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do compile { target c++2a } }
struct S { };
constinit extern S s;
constinit S s2 = { };
struct T {
int i;
};
constinit T t;
struct U : T {
int j;
};
constinit U u;

27
gcc/testsuite/g++.dg/cpp2a/constinit5.C Normal file
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@ -0,0 +1,27 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do compile { target c++2a } }
// Check that we preserve DECL_DECLARED_CONSTINIT_P in duplicate_decls.
int gl = 42;
struct S {
constinit static int m;
constinit static int n;
constinit static const int &r1;
constinit static const int &r2;
};
int S::m = 42;
int nonconst;
constinit int S::n = nonconst; // { dg-error "variable .S::n. does not have a constant initializer" }
// { dg-error "not usable in a constant expression" "" { target *-*-* } .-1 }
const int &S::r1 = gl;
const int &S::r2 = 42;
struct T {
constinit static thread_local const int &r1;
constinit static thread_local const int &r2;
};
constinit thread_local const int &T::r1 = gl;
constinit thread_local const int &T::r2 = 42; // { dg-error "variable .T::r2. does not have a constant initializer|not a constant expression" }

5
gcc/testsuite/g++.dg/cpp2a/constinit6.C Normal file
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@ -0,0 +1,5 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do compile { target c++17_down } }
// { dg-options "-Wc++20-compat" }
int constinit; // { dg-warning "identifier .constinit. is a keyword" }

11
gcc/testsuite/g++.dg/cpp2a/constinit7.C Normal file
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@ -0,0 +1,11 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do compile { target c++11 } }
struct T {
constexpr T(int) {}
~T();
};
__constinit T x = { 42 };
// ??? This should be rejected in C++14: copy initialization is not a constant
// expression on a non-literal type in C++14. But 'constinit' is C++20 only.
__constinit T y = 42;

18
gcc/testsuite/g++.dg/cpp2a/constinit8.C Normal file
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@ -0,0 +1,18 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do compile { target c++2a } }
// Variable templates.
int nonconst;
template<typename T>
constinit T v1 = 42;
template<typename T>
constinit T v2 = nonconst; // { dg-error "does not have a constant initializer|not usable" }
void
fn ()
{
v1<int>;
v2<int>;
}

24
gcc/testsuite/g++.dg/cpp2a/constinit9.C Normal file
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@ -0,0 +1,24 @@
// PR c++/91360 - Implement C++20 P1143R2: constinit
// { dg-do run { target c++2a } }
// A run-time test.
constexpr int foo (int x) { return x; }
constinit int b = foo(42);
int
main ()
{
if (b != 42)
__builtin_abort ();
// We can still modify 'b'.
b = 10;
if (b != 10)
__builtin_abort ();
constinit static int s = foo(14);
if (s != 14)
__builtin_abort ();
s++;
if (s != 15)
__builtin_abort ();
}