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C front-end: fallthrough and __fallthrough__ are the same attribute #5730

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Merged
merged 1 commit into from
Mar 15, 2021
Merged

C front-end: fallthrough and __fallthrough__ are the same attribute #5730

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17 changes: 12 additions & 5 deletions regression/ansi-c/gcc_attributes13/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -7,13 +7,20 @@ int main()
int x;
switch(x)
{
case 1:
x = 2;
case 1:
x = 2;
#ifdef __GNUC__
__attribute__((fallthrough));
__attribute__((fallthrough));
#endif
case 2:
x = 3;
case 2:
{
x = 3;
#ifdef __GNUC__
__attribute__((__fallthrough__));
#endif
}
case 3:
break;
}

return 0;
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29 changes: 13 additions & 16 deletions src/ansi-c/parser.y
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Expand Up @@ -1655,6 +1655,11 @@ gcc_attribute:
{
init($$);
}
| TOK_GCC_ATTRIBUTE_FALLTHROUGH
{
// attribute ignored
init($$);
}
| gcc_type_attribute
;

Expand Down Expand Up @@ -2320,19 +2325,7 @@ declaration_statement:
;

labeled_statement:
identifier_or_typedef_name ':' gcc_attribute_specifier ';'
{
/* Only semicolons permitted after the attribute:
https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html */
$$=$2;
statement($$, ID_label);
irep_idt identifier=PARSER.lookup_label(parser_stack($1).get(ID_C_base_name));
parser_stack($$).set(ID_label, identifier);
// attribute ignored
statement($3, ID_skip);
mto($$, $3);
}
| identifier_or_typedef_name ':' statement
identifier_or_typedef_name ':' statement
{
$$=$2;
statement($$, ID_label);
Expand Down Expand Up @@ -2367,10 +2360,14 @@ labeled_statement:
;

statement_attribute:
TOK_GCC_ATTRIBUTE '(' '(' TOK_GCC_ATTRIBUTE_FALLTHROUGH ')' ')' ';' labeled_statement
gcc_attribute_specifier ';'
{
// attribute ignored
$$=$8;
// Really should only be TOK_GCC_ATTRIBUTE_FALLTHROUGH or a label
// attribute. Only semicolons permitted after the attribute:
// https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html
// We ignore all such attributes.
$$=$1;
statement($$, ID_skip);
}
;

Expand Down
3 changes: 2 additions & 1 deletion src/ansi-c/scanner.l
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Expand Up @@ -1704,7 +1704,8 @@ __decltype { if(PARSER.cpp98 &&
"destructor" |
"__destructor__" { BEGIN(GCC_ATTRIBUTE3); loc(); return TOK_GCC_ATTRIBUTE_DESTRUCTOR; }

"fallthrough" { BEGIN(GCC_ATTRIBUTE3); loc(); return TOK_GCC_ATTRIBUTE_FALLTHROUGH; }
"fallthrough" |
"__fallthrough__" { BEGIN(GCC_ATTRIBUTE3); loc(); return TOK_GCC_ATTRIBUTE_FALLTHROUGH; }

"used" |
"__used__" { BEGIN(GCC_ATTRIBUTE3); loc(); return TOK_GCC_ATTRIBUTE_USED; }
Expand Down