* [PATCH v2] c: Error message for incorrect use of static in array declarations
@ 2024-06-26 18:01 Martin Uecker
2024-06-26 21:17 ` Marek Polacek
0 siblings, 1 reply; 2+ messages in thread
From: Martin Uecker @ 2024-06-26 18:01 UTC (permalink / raw)
To: gcc-patches; +Cc: Joseph Myers, Marek Polacek
Thanks Marek, here is the second version which should
implement all your suggestions.
(BTW: Without the newline of the end, the test case has
undefined behavior..., not that we need to care.)
Bootstrapped and regression tested on x86_64.
[PATCH] c: Error message for incorrect use of static in array declarations.
Add an explicit error messages when c99's static is
used without a size expression in an array declarator.
gcc/c:
c-parser.cc (c_parser_direct_declarator_inner): Add
error message.
gcc/testsuite:
gcc.dg/c99-arraydecl-4.c: New test.
diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 6a3f96d5b61..db60507252b 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -4715,8 +4715,6 @@ c_parser_direct_declarator_inner (c_parser *parser, bool id_present,
location_t brace_loc = c_parser_peek_token (parser)->location;
struct c_declarator *declarator;
struct c_declspecs *quals_attrs = build_null_declspecs ();
- bool static_seen;
- bool star_seen;
struct c_expr dimen;
dimen.value = NULL_TREE;
dimen.original_code = ERROR_MARK;
@@ -4724,7 +4722,8 @@ c_parser_direct_declarator_inner (c_parser *parser, bool id_present,
c_parser_consume_token (parser);
c_parser_declspecs (parser, quals_attrs, false, false, true,
false, false, false, false, cla_prefer_id);
- static_seen = c_parser_next_token_is_keyword (parser, RID_STATIC);
+ const bool static_seen = c_parser_next_token_is_keyword (parser,
+ RID_STATIC);
if (static_seen)
c_parser_consume_token (parser);
if (static_seen && !quals_attrs->declspecs_seen_p)
@@ -4735,38 +4734,34 @@ c_parser_direct_declarator_inner (c_parser *parser, bool id_present,
/* If "static" is present, there must be an array dimension.
Otherwise, there may be a dimension, "*", or no
dimension. */
- if (static_seen)
+ bool star_seen = false;
+ if (c_parser_next_token_is (parser, CPP_MULT)
+ && c_parser_peek_2nd_token (parser)->type == CPP_CLOSE_SQUARE)
{
- star_seen = false;
- dimen = c_parser_expr_no_commas (parser, NULL);
+ star_seen = true;
+ c_parser_consume_token (parser);
}
- else
+ else if (!c_parser_next_token_is (parser, CPP_CLOSE_SQUARE))
+ dimen = c_parser_expr_no_commas (parser, NULL);
+
+ if (static_seen)
{
- if (c_parser_next_token_is (parser, CPP_CLOSE_SQUARE))
+ if (star_seen)
{
- dimen.value = NULL_TREE;
+ error_at (c_parser_peek_token (parser)->location,
+ "%<static%> may not be used with an unspecified "
+ "variable length array size");
+ /* Prevent further errors. */
star_seen = false;
+ dimen.value = error_mark_node;
}
- else if (c_parser_next_token_is (parser, CPP_MULT))
- {
- if (c_parser_peek_2nd_token (parser)->type == CPP_CLOSE_SQUARE)
- {
- dimen.value = NULL_TREE;
- star_seen = true;
- c_parser_consume_token (parser);
- }
- else
- {
- star_seen = false;
- dimen = c_parser_expr_no_commas (parser, NULL);
- }
- }
- else
+ else if (!dimen.value)
{
- star_seen = false;
- dimen = c_parser_expr_no_commas (parser, NULL);
+ error_at (c_parser_peek_token (parser)->location,
+ "%<static%> may not be used without an array size");
}
}
+
if (c_parser_next_token_is (parser, CPP_CLOSE_SQUARE))
c_parser_consume_token (parser);
else
diff --git a/gcc/testsuite/gcc.dg/c99-arraydecl-4.c b/gcc/testsuite/gcc.dg/c99-arraydecl-4.c
new file mode 100644
index 00000000000..f8cad3b9429
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c99-arraydecl-4.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c99 -pedantic-errors" } */
+
+void fo(char buf[static]); /* { dg-error "'static' may not be used without an array size" } */
+void fo(char buf[static]) { } /* { dg-error "'static' may not be used without an array size" } */
+
+void fu(char buf[static *]); /* { dg-error "'static' may not be used with an unspecified variable length array size" } */
+void fu(char buf[static *]) { } /* { dg-error "'static' may not be used with an unspecified variable length array size" } */
+
+void fe(int n, char buf[static n]);
+void fe(int n, char buf[static *]) { } /* { dg-error "'static' may not be used with an unspecified variable length array size" } */
+
+void fa(int *n, char buf[static *n]);
+void fa(int *n, char buf[static *n]) { }
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH v2] c: Error message for incorrect use of static in array declarations
2024-06-26 18:01 [PATCH v2] c: Error message for incorrect use of static in array declarations Martin Uecker
@ 2024-06-26 21:17 ` Marek Polacek
0 siblings, 0 replies; 2+ messages in thread
From: Marek Polacek @ 2024-06-26 21:17 UTC (permalink / raw)
To: Martin Uecker; +Cc: gcc-patches, Joseph Myers
On Wed, Jun 26, 2024 at 08:01:57PM +0200, Martin Uecker wrote:
>
> Thanks Marek, here is the second version which should
> implement all your suggestions.
Thanks!
> (BTW: Without the newline of the end, the test case has
> undefined behavior..., not that we need to care.)
>
>
> Bootstrapped and regression tested on x86_64.
>
>
> [PATCH] c: Error message for incorrect use of static in array declarations.
>
> Add an explicit error messages when c99's static is
> used without a size expression in an array declarator.
>
> gcc/c:
> c-parser.cc (c_parser_direct_declarator_inner): Add
> error message.
>
> gcc/testsuite:
> gcc.dg/c99-arraydecl-4.c: New test.
>
> diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
> index 6a3f96d5b61..db60507252b 100644
> --- a/gcc/c/c-parser.cc
> +++ b/gcc/c/c-parser.cc
> @@ -4715,8 +4715,6 @@ c_parser_direct_declarator_inner (c_parser *parser, bool id_present,
> location_t brace_loc = c_parser_peek_token (parser)->location;
> struct c_declarator *declarator;
> struct c_declspecs *quals_attrs = build_null_declspecs ();
> - bool static_seen;
> - bool star_seen;
> struct c_expr dimen;
> dimen.value = NULL_TREE;
> dimen.original_code = ERROR_MARK;
> @@ -4724,7 +4722,8 @@ c_parser_direct_declarator_inner (c_parser *parser, bool id_present,
> c_parser_consume_token (parser);
> c_parser_declspecs (parser, quals_attrs, false, false, true,
> false, false, false, false, cla_prefer_id);
> - static_seen = c_parser_next_token_is_keyword (parser, RID_STATIC);
> + const bool static_seen = c_parser_next_token_is_keyword (parser,
> + RID_STATIC);
> if (static_seen)
> c_parser_consume_token (parser);
> if (static_seen && !quals_attrs->declspecs_seen_p)
> @@ -4735,38 +4734,34 @@ c_parser_direct_declarator_inner (c_parser *parser, bool id_present,
> /* If "static" is present, there must be an array dimension.
> Otherwise, there may be a dimension, "*", or no
> dimension. */
> - if (static_seen)
> + bool star_seen = false;
> + if (c_parser_next_token_is (parser, CPP_MULT)
> + && c_parser_peek_2nd_token (parser)->type == CPP_CLOSE_SQUARE)
> {
> - star_seen = false;
> - dimen = c_parser_expr_no_commas (parser, NULL);
> + star_seen = true;
> + c_parser_consume_token (parser);
> }
> - else
> + else if (!c_parser_next_token_is (parser, CPP_CLOSE_SQUARE))
> + dimen = c_parser_expr_no_commas (parser, NULL);
> +
> + if (static_seen)
> {
> - if (c_parser_next_token_is (parser, CPP_CLOSE_SQUARE))
> + if (star_seen)
> {
> - dimen.value = NULL_TREE;
> + error_at (c_parser_peek_token (parser)->location,
Now I realize that the location is not ideal here, it points to the
closing ], but we can easily get the location of "static". So perhaps:
location_t static_loc = UNKNOWN_LOCATION;
if (c_parser_next_token_is_keyword (parser, RID_STATIC))
{
static_loc = c_parser_peek_token (parser)->location;
c_parser_consume_token (parser);
}
and then use "seen_loc != UNKNOWN_LOCATION" instead of the bool, or
do
const bool static_seen = (static_loc != UNKNOWN_LOCATION);
if you prefer.
> + "%<static%> may not be used with an unspecified "
> + "variable length array size");
> + /* Prevent further errors. */
> star_seen = false;
> + dimen.value = error_mark_node;
> }
> - else if (c_parser_next_token_is (parser, CPP_MULT))
> - {
> - if (c_parser_peek_2nd_token (parser)->type == CPP_CLOSE_SQUARE)
> - {
> - dimen.value = NULL_TREE;
> - star_seen = true;
> - c_parser_consume_token (parser);
> - }
> - else
> - {
> - star_seen = false;
> - dimen = c_parser_expr_no_commas (parser, NULL);
> - }
> - }
> - else
> + else if (!dimen.value)
> {
> - star_seen = false;
> - dimen = c_parser_expr_no_commas (parser, NULL);
> + error_at (c_parser_peek_token (parser)->location,
> + "%<static%> may not be used without an array size");
> }
No need to have { } around a single statement.
Marek
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