* [C PATCH] C: Error message for incorrect use of static in array declarations
@ 2024-06-23 18:42 Martin Uecker
2024-06-24 20:41 ` Marek Polacek
0 siblings, 1 reply; 2+ messages in thread
From: Martin Uecker @ 2024-06-23 18:42 UTC (permalink / raw)
To: gcc-patches; +Cc: Joseph Myers
This adds an explicit error message for [static] and [static*]
(the same as clang has) instead of the generic "error: expected
expression before ']' token", which is not entirely accurate.
For function definitions the subsequent error "[*] can not be
used outside function prototype scope" is then suppressed.
Bootstrapped and regression tested on x86_64.
commit 1157d04764eeeb51fa1098727813dbc092e11dd2
Author: Martin Uecker <uecker@tugraz.at>
Date: Sat Nov 4 14:39:19 2023 +0100
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 e83e9c683f7..91b8d24ca78 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -4732,41 +4732,29 @@ c_parser_direct_declarator_inner (c_parser *parser, bool id_present,
false, false, false, false, cla_prefer_id);
if (!quals_attrs->declspecs_seen_p)
quals_attrs = NULL;
- /* If "static" is present, there must be an array dimension.
- Otherwise, there may be a dimension, "*", or no
- dimension. */
- if (static_seen)
+
+ 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 && star_seen)
{
- if (c_parser_next_token_is (parser, CPP_CLOSE_SQUARE))
- {
- dimen.value = NULL_TREE;
- star_seen = false;
- }
- 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
- {
- star_seen = false;
- dimen = c_parser_expr_no_commas (parser, NULL);
- }
+ 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;
}
+ else if (static_seen && NULL_TREE == dimen.value)
+ 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..bfc26196433
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/c99-arraydecl-4.c
@@ -0,0 +1,15 @@
+/* { 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: [C PATCH] C: Error message for incorrect use of static in array declarations
2024-06-23 18:42 [C PATCH] C: Error message for incorrect use of static in array declarations Martin Uecker
@ 2024-06-24 20:41 ` Marek Polacek
0 siblings, 0 replies; 2+ messages in thread
From: Marek Polacek @ 2024-06-24 20:41 UTC (permalink / raw)
To: Martin Uecker; +Cc: gcc-patches, Joseph Myers
On Sun, Jun 23, 2024 at 08:42:36PM +0200, Martin Uecker wrote:
>
> This adds an explicit error message for [static] and [static*]
> (the same as clang has) instead of the generic "error: expected
> expression before ']' token", which is not entirely accurate.
> For function definitions the subsequent error "[*] can not be
> used outside function prototype scope" is then suppressed.
>
>
> Bootstrapped and regression tested on x86_64.
>
>
>
> commit 1157d04764eeeb51fa1098727813dbc092e11dd2
> Author: Martin Uecker <uecker@tugraz.at>
> Date: Sat Nov 4 14:39:19 2023 +0100
>
> C: Error message for incorrect use of static in array declarations.
Please use "[PATCH] c: ..." for C patches.
> 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.
No "c/" here.
>
> 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 e83e9c683f7..91b8d24ca78 100644
> --- a/gcc/c/c-parser.cc
> +++ b/gcc/c/c-parser.cc
> @@ -4732,41 +4732,29 @@ c_parser_direct_declarator_inner (c_parser *parser, bool id_present,
> false, false, false, false, cla_prefer_id);
> if (!quals_attrs->declspecs_seen_p)
> quals_attrs = NULL;
FWIW, I'd prefer to use
const bool static_seen = c_parser_next_token_is_keyword (parser, RID_STATIC);
> - /* If "static" is present, there must be an array dimension.
> - Otherwise, there may be a dimension, "*", or no
> - dimension. */
Why remove the comment?
> - if (static_seen)
> +
> + star_seen = false;
bool star_seen = false; would be nicer IMHO.
> + 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 && star_seen)
> {
> - if (c_parser_next_token_is (parser, CPP_CLOSE_SQUARE))
> - {
> - dimen.value = NULL_TREE;
> - star_seen = false;
> - }
> - 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
> - {
> - star_seen = false;
> - dimen = c_parser_expr_no_commas (parser, NULL);
> - }
> + error_at (c_parser_peek_token (parser)->location,
> + "%<static%> may not be used with an unspecified "
> + "variable length array size");
The last two lines are not indented enough.
> + /* Prevent further errors. */
Two spaces after a '.'.
> + star_seen = false;
> }
> + else if (static_seen && NULL_TREE == dimen.value)
Please let's use !dimen.value or dimen.value == NULL_TREE instead.
I think it'd be better to do:
if (static_seen)
{
if (star_seen)
// ...
else if (!dimen.value)
// ...
}
> + 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..bfc26196433
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/c99-arraydecl-4.c
> @@ -0,0 +1,15 @@
> +/* { dg-do "compile" } */
It's unusual to quote compile here.
> +/* { 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" } */
With -Wvla-parameter we get:
c99-arraydecl-4.c:11:21: warning: argument 2 of type 'char[]' declared as an ordinary array
c99-arraydecl-4.c:10:21: note: previously declared as a variable length array 'char[static n]'
which seems wrong; should we set
dimen.value = error_mark_node;
in the static_seen && star_seen case?
> +void fa(int *n, char buf[static *n]);
> +void fa(int *n, char buf[static *n]) { }
> +
Spurious newline.
Marek
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2024-06-24 20:41 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-06-23 18:42 [C PATCH] C: Error message for incorrect use of static in array declarations Martin Uecker
2024-06-24 20:41 ` Marek Polacek
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).