N2557, accepted into C2x at the October WG14 meeting, removes the
requirement that duplicates of standard attributes cannot appear
within an attribute list (so allowing e.g. [[deprecated, deprecated]],
where previously that was disallowed but [[deprecated]] [[deprecated]]
was OK). Remove the code checking for this (standard attributes
aren't in any released version of the C standard) and update tests
accordingly.
Bootstrapped with no regressions on x86_64-pc-linux-gnu. Applied to
mainline.
gcc/c/
2020-10-27 Joseph Myers <jos...@codesourcery.com>
* c-parser.c (c_parser_std_attribute_specifier): Allow duplicate
standard attributes.
gcc/testsuite/
2020-10-27 Joseph Myers <jos...@codesourcery.com>
* gcc.dg/c2x-attr-deprecated-4.c, gcc.dg/c2x-attr-fallthrough-4.c,
gcc.dg/c2x-attr-maybe_unused-4.c: Allow duplicate attributes.
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index b6a7ef4c92b..d49e508ce6d 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -4977,9 +4977,6 @@ c_parser_std_attribute (c_parser *parser, bool for_tm)
static tree
c_parser_std_attribute_specifier (c_parser *parser, bool for_tm)
{
- bool seen_deprecated = false;
- bool seen_fallthrough = false;
- bool seen_maybe_unused = false;
location_t loc = c_parser_peek_token (parser)->location;
if (!c_parser_require (parser, CPP_OPEN_SQUARE, "expected %<[%>"))
return NULL_TREE;
@@ -5005,55 +5002,8 @@ c_parser_std_attribute_specifier (c_parser *parser, bool
for_tm)
tree attribute = c_parser_std_attribute (parser, for_tm);
if (attribute != error_mark_node)
{
- bool duplicate = false;
- tree name = get_attribute_name (attribute);
- tree ns = get_attribute_namespace (attribute);
- if (ns == NULL_TREE)
- {
- /* Some standard attributes may appear at most once in
- each attribute list. Diagnose duplicates and remove
- them from the list to avoid subsequent diagnostics
- such as the more general one for multiple
- "fallthrough" attributes in the same place (including
- in separate attribute lists in the same attribute
- specifier sequence, which is not a constraint
- violation). */
- if (is_attribute_p ("deprecated", name))
- {
- if (seen_deprecated)
- {
- error ("attribute %<deprecated%> can appear at most "
- "once in an attribute-list");
- duplicate = true;
- }
- seen_deprecated = true;
- }
- else if (is_attribute_p ("fallthrough", name))
- {
- if (seen_fallthrough)
- {
- error ("attribute %<fallthrough%> can appear at most "
- "once in an attribute-list");
- duplicate = true;
- }
- seen_fallthrough = true;
- }
- else if (is_attribute_p ("maybe_unused", name))
- {
- if (seen_maybe_unused)
- {
- error ("attribute %<maybe_unused%> can appear at most "
- "once in an attribute-list");
- duplicate = true;
- }
- seen_maybe_unused = true;
- }
- }
- if (!duplicate)
- {
- TREE_CHAIN (attribute) = attributes;
- attributes = attribute;
- }
+ TREE_CHAIN (attribute) = attributes;
+ attributes = attribute;
}
if (c_parser_next_token_is_not (parser, CPP_COMMA))
break;
diff --git a/gcc/testsuite/gcc.dg/c2x-attr-deprecated-4.c
b/gcc/testsuite/gcc.dg/c2x-attr-deprecated-4.c
index f1848a20cd5..7698434cc6d 100644
--- a/gcc/testsuite/gcc.dg/c2x-attr-deprecated-4.c
+++ b/gcc/testsuite/gcc.dg/c2x-attr-deprecated-4.c
@@ -1,13 +1,11 @@
-/* Test C2x deprecated attribute: duplicates. */
+/* Test C2x deprecated attribute: duplicates (allowed after N2557). */
/* { dg-do compile } */
/* { dg-options "-std=c2x -pedantic-errors" } */
-[[deprecated, __deprecated__]] int a; /* { dg-error "can appear at most once"
} */
-[[__deprecated__, deprecated("message")]] int b; /* { dg-error "can appear at
most once" } */
-int c [[deprecated("message"), deprecated]]; /* { dg-error "can appear at most
once" } */
-[[deprecated, deprecated]]; /* { dg-error "can appear at most once" } */
+[[deprecated, __deprecated__]] int a;
+[[__deprecated__, deprecated("message")]] int b;
+int c [[deprecated("message"), deprecated]];
+[[deprecated, deprecated]];
/* { dg-error "ignored" "ignored" { target *-*-* } .-1 } */
-/* Separate attribute lists in the same attribute specifier sequence,
- with the same attribute in them, are OK. */
[[deprecated]] [[deprecated]] int d [[deprecated]] [[deprecated]];
diff --git a/gcc/testsuite/gcc.dg/c2x-attr-fallthrough-4.c
b/gcc/testsuite/gcc.dg/c2x-attr-fallthrough-4.c
index 75aceff9941..a6cedcd0042 100644
--- a/gcc/testsuite/gcc.dg/c2x-attr-fallthrough-4.c
+++ b/gcc/testsuite/gcc.dg/c2x-attr-fallthrough-4.c
@@ -1,4 +1,4 @@
-/* Test C2x fallthrough attribute: duplicates. */
+/* Test C2x fallthrough attribute: duplicates (allowed after N2557). */
/* { dg-do compile } */
/* { dg-options "-std=c2x -pedantic-errors" } */
@@ -9,12 +9,9 @@ f (int a)
{
case 1:
a++;
- [[fallthrough, __fallthrough__]]; /* { dg-error "can appear at most
once" } */
+ [[fallthrough, __fallthrough__]]; /* { dg-warning "specified multiple
times" } */
case 2:
a++;
- /* Separate attribute lists in the same attribute specifier
- sequence, with the same attribute in them, are OK (but
- receive a warning). */
[[fallthrough]] [[fallthrough]]; /* { dg-warning "specified multiple
times" } */
case 3:
a++;
diff --git a/gcc/testsuite/gcc.dg/c2x-attr-maybe_unused-4.c
b/gcc/testsuite/gcc.dg/c2x-attr-maybe_unused-4.c
index 300c0dae73c..6b997aa0033 100644
--- a/gcc/testsuite/gcc.dg/c2x-attr-maybe_unused-4.c
+++ b/gcc/testsuite/gcc.dg/c2x-attr-maybe_unused-4.c
@@ -1,13 +1,11 @@
-/* Test C2x maybe_unused attribute: duplicates. */
+/* Test C2x maybe_unused attribute: duplicates (allowed after N2557). */
/* { dg-do compile } */
/* { dg-options "-std=c2x -pedantic-errors" } */
-[[maybe_unused, __maybe_unused__]] int a; /* { dg-error "can appear at most
once" } */
-[[__maybe_unused__, maybe_unused]] int b; /* { dg-error "can appear at most
once" } */
-int c [[maybe_unused, maybe_unused]]; /* { dg-error "can appear at most once"
} */
-[[maybe_unused, maybe_unused]]; /* { dg-error "can appear at most once" } */
+[[maybe_unused, __maybe_unused__]] int a;
+[[__maybe_unused__, maybe_unused]] int b;
+int c [[maybe_unused, maybe_unused]];
+[[maybe_unused, maybe_unused]];
/* { dg-error "ignored" "ignored" { target *-*-* } .-1 } */
-/* Separate attribute lists in the same attribute specifier sequence,
- with the same attribute in them, are OK. */
[[maybe_unused]] [[maybe_unused]] int d [[maybe_unused]] [[maybe_unused]];
--
Joseph S. Myers
jos...@codesourcery.com
