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authorAndi Kleen <ak@linux.intel.com>2024-01-24 07:44:23 -0800
committerAndi Kleen <ak@gcc.gnu.org>2024-07-19 23:28:58 -0700
commit7db47f7b915c5f5d645fa536547e26b92290afe3 (patch)
treeec93fee82d935cdedc107b9fad9792a9d28a0cf6 /gcc/c/c-parser.cc
parent59dd1d7ab21ad9a7ebf641ec9aeea609c003ad2f (diff)
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C: Implement musttail attribute for returns
Implement a C23 clang compatible musttail attribute similar to the earlier C++ implementation in the C parser. gcc/c/ChangeLog: PR c/83324 * c-parser.cc (struct attr_state): Define with musttail_p. (c_parser_statement_after_labels): Handle [[musttail]]. (c_parser_std_attribute): Dito. (c_parser_handle_musttail): Dito. (c_parser_compound_statement_nostart): Dito. (c_parser_all_labels): Dito. (c_parser_statement): Dito. * c-tree.h (c_finish_return): Add musttail_p flag. * c-typeck.cc (c_finish_return): Handle musttail_p flag.
Diffstat (limited to 'gcc/c/c-parser.cc')
-rw-r--r--gcc/c/c-parser.cc71
1 files changed, 58 insertions, 13 deletions
diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 12c5ed5..9b9284b 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -1621,6 +1621,12 @@ struct omp_for_parse_data {
bool fail : 1;
};
+struct attr_state
+{
+ /* True if we parsed a musttail attribute for return. */
+ bool musttail_p;
+};
+
static bool c_parser_nth_token_starts_std_attributes (c_parser *,
unsigned int);
static tree c_parser_std_attribute_specifier_sequence (c_parser *);
@@ -1665,7 +1671,8 @@ static location_t c_parser_compound_statement_nostart (c_parser *);
static void c_parser_label (c_parser *, tree);
static void c_parser_statement (c_parser *, bool *, location_t * = NULL);
static void c_parser_statement_after_labels (c_parser *, bool *,
- vec<tree> * = NULL);
+ vec<tree> * = NULL,
+ attr_state = {});
static tree c_parser_c99_block_statement (c_parser *, bool *,
location_t * = NULL);
static void c_parser_if_statement (c_parser *, bool *, vec<tree> *);
@@ -6982,6 +6989,29 @@ c_parser_handle_directive_omp_attributes (tree &attrs,
}
}
+/* Check if STD_ATTR contains a musttail attribute and remove if it
+ precedes a return. PARSER is the parser and ATTR is the output
+ attr_state. */
+
+static tree
+c_parser_handle_musttail (c_parser *parser, tree std_attrs, attr_state &attr)
+{
+ if (c_parser_next_token_is_keyword (parser, RID_RETURN))
+ {
+ if (lookup_attribute ("gnu", "musttail", std_attrs))
+ {
+ std_attrs = remove_attribute ("gnu", "musttail", std_attrs);
+ attr.musttail_p = true;
+ }
+ if (lookup_attribute ("clang", "musttail", std_attrs))
+ {
+ std_attrs = remove_attribute ("clang", "musttail", std_attrs);
+ attr.musttail_p = true;
+ }
+ }
+ return std_attrs;
+}
+
/* Parse a compound statement except for the opening brace. This is
used for parsing both compound statements and statement expressions
(which follow different paths to handling the opening). */
@@ -6998,6 +7028,7 @@ c_parser_compound_statement_nostart (c_parser *parser)
bool in_omp_loop_block
= omp_for_parse_state ? omp_for_parse_state->want_nested_loop : false;
tree sl = NULL_TREE;
+ attr_state a = {};
if (c_parser_next_token_is (parser, CPP_CLOSE_BRACE))
{
@@ -7138,7 +7169,10 @@ c_parser_compound_statement_nostart (c_parser *parser)
= c_parser_nth_token_starts_std_attributes (parser, 1);
tree std_attrs = NULL_TREE;
if (have_std_attrs)
- std_attrs = c_parser_std_attribute_specifier_sequence (parser);
+ {
+ std_attrs = c_parser_std_attribute_specifier_sequence (parser);
+ std_attrs = c_parser_handle_musttail (parser, std_attrs, a);
+ }
if (c_parser_next_token_is_keyword (parser, RID_CASE)
|| c_parser_next_token_is_keyword (parser, RID_DEFAULT)
|| (c_parser_next_token_is (parser, CPP_NAME)
@@ -7286,7 +7320,7 @@ c_parser_compound_statement_nostart (c_parser *parser)
last_stmt = true;
mark_valid_location_for_stdc_pragma (false);
if (!omp_for_parse_state)
- c_parser_statement_after_labels (parser, NULL);
+ c_parser_statement_after_labels (parser, NULL, NULL, a);
else
{
/* In canonical loop nest form, nested loops can only appear
@@ -7328,15 +7362,20 @@ c_parser_compound_statement_nostart (c_parser *parser)
/* Parse all consecutive labels, possibly preceded by standard
attributes. In this context, a statement is required, not a
declaration, so attributes must be followed by a statement that is
- not just a semicolon. */
+ not just a semicolon. Returns an attr_state. */
-static void
+static attr_state
c_parser_all_labels (c_parser *parser)
{
+ attr_state attr = {};
bool have_std_attrs;
tree std_attrs = NULL;
if ((have_std_attrs = c_parser_nth_token_starts_std_attributes (parser, 1)))
- std_attrs = c_parser_std_attribute_specifier_sequence (parser);
+ {
+ std_attrs = c_parser_std_attribute_specifier_sequence (parser);
+ std_attrs = c_parser_handle_musttail (parser, std_attrs, attr);
+ }
+
while (c_parser_next_token_is_keyword (parser, RID_CASE)
|| c_parser_next_token_is_keyword (parser, RID_DEFAULT)
|| (c_parser_next_token_is (parser, CPP_NAME)
@@ -7346,7 +7385,10 @@ c_parser_all_labels (c_parser *parser)
std_attrs = NULL;
if ((have_std_attrs = c_parser_nth_token_starts_std_attributes (parser,
1)))
- std_attrs = c_parser_std_attribute_specifier_sequence (parser);
+ {
+ std_attrs = c_parser_std_attribute_specifier_sequence (parser);
+ std_attrs = c_parser_handle_musttail (parser, std_attrs, attr);
+ }
}
if (std_attrs
&& (!c_parser_handle_statement_omp_attributes (parser, std_attrs, &have_std_attrs)
@@ -7358,6 +7400,7 @@ c_parser_all_labels (c_parser *parser)
}
else if (have_std_attrs && c_parser_next_token_is (parser, CPP_SEMICOLON))
c_parser_error (parser, "expected statement");
+ return attr;
}
/* Parse a label (C90 6.6.1, C99 6.8.1, C11 6.8.1).
@@ -7601,11 +7644,11 @@ c_parser_label (c_parser *parser, tree std_attrs)
static void
c_parser_statement (c_parser *parser, bool *if_p, location_t *loc_after_labels)
{
- c_parser_all_labels (parser);
+ attr_state a = c_parser_all_labels (parser);
if (loc_after_labels)
*loc_after_labels = c_parser_peek_token (parser)->location;
parser->omp_attrs_forbidden_p = false;
- c_parser_statement_after_labels (parser, if_p, NULL);
+ c_parser_statement_after_labels (parser, if_p, NULL, a);
}
/* Parse a statement, other than a labeled statement. CHAIN is a vector
@@ -7614,11 +7657,11 @@ c_parser_statement (c_parser *parser, bool *if_p, location_t *loc_after_labels)
IF_P is used to track whether there's a (possibly labeled) if statement
which is not enclosed in braces and has an else clause. This is used to
- implement -Wparentheses. */
+ implement -Wparentheses. ASTATE is an earlier parsed attribute state. */
static void
c_parser_statement_after_labels (c_parser *parser, bool *if_p,
- vec<tree> *chain)
+ vec<tree> *chain, attr_state astate)
{
location_t loc = c_parser_peek_token (parser)->location;
tree stmt = NULL_TREE;
@@ -7686,7 +7729,8 @@ c_parser_statement_after_labels (c_parser *parser, bool *if_p,
c_parser_consume_token (parser);
if (c_parser_next_token_is (parser, CPP_SEMICOLON))
{
- stmt = c_finish_return (loc, NULL_TREE, NULL_TREE);
+ stmt = c_finish_return (loc, NULL_TREE, NULL_TREE,
+ astate.musttail_p);
c_parser_consume_token (parser);
}
else
@@ -7695,7 +7739,8 @@ c_parser_statement_after_labels (c_parser *parser, bool *if_p,
struct c_expr expr = c_parser_expression_conv (parser);
mark_exp_read (expr.value);
stmt = c_finish_return (EXPR_LOC_OR_LOC (expr.value, xloc),
- expr.value, expr.original_type);
+ expr.value, expr.original_type,
+ astate.musttail_p);
goto expect_semicolon;
}
break;
generated by cgit v1.1 at 2025-03-30 13:35:36 +0000