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| author | Ramsay Jones <ramsay@ramsayjones.plus.com> | 2021-09-28 00:45:22 +0100 |
|---|---|---|
| committer | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2022-05-20 10:55:05 +0200 |
| commit | d08822184fe1d4557beca97c2e3599ffc3668e50 (patch) | |
| tree | fd21e6b95ea88839593466e8c6f4db304f942824 | |
| parent | 4cd76bd9eeb3777219a307893e33d072df05eb37 (diff) | |
| download | sparse-d08822184fe1d4557beca97c2e3599ffc3668e50.tar.gz | |
parse: warn about a 'case label' on empty statement
Commit 0d6bb7e1 ("handle more graciously labels with no statement",
2020-10-26) allowed a label to appear just before the closing brace
of a compound statement. This is not valid C (which would require
at least a null statement). Similarly, a case label is also not
allowed to appear just before a closing brace.
So, extend the solution of commit 0d6bb7e1 to issue a warning for
case labels and 'insert' a null statement.
Note that the next C standard (C23 ?) will allow even more freedom
in the placement of labels (see N2508 [1]) and make this placement
(along with others) legal C.
[1] https://www9.open-std.org/JTC1/SC22/WG14/www/docs/n2508.pdf
Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
| -rw-r--r-- | parse.c | 5 | ||||
| -rw-r--r-- | validation/label-positioning.c | 22 |
2 files changed, 27 insertions, 0 deletions
@@ -2329,6 +2329,11 @@ static inline struct token *case_statement(struct token *token, struct statement stmt->type = STMT_CASE; token = expect(token, ':', "after default/case"); add_case_statement(stmt); + if (match_op(token, '}')) { + warning(token->pos, "statement expected after case label"); + stmt->case_statement = alloc_statement(token->pos, STMT_NONE); + return token; + } return statement(token, &stmt->case_statement); } diff --git a/validation/label-positioning.c b/validation/label-positioning.c new file mode 100644 index 00000000..583661ca --- /dev/null +++ b/validation/label-positioning.c @@ -0,0 +1,22 @@ +extern int someval(void); + +static void func (int x) +{ + if (x > someval()) + goto end; + switch (x) { case 0: } + switch (x) { case 1 ... 9: } + switch (x) { default: } +end: +} + +/* + * check-name: label-positioning + * + * check-error-start +label-positioning.c:7:30: warning: statement expected after case label +label-positioning.c:8:36: warning: statement expected after case label +label-positioning.c:9:31: warning: statement expected after case label +label-positioning.c:11:1: warning: statement expected after label + * check-error-end + */ |