* [FFmpeg-devel] [PATCH] fftools/opt_common: remove dead code in print_buildconf()
@ 2024-03-12 22:41 Marth64
2024-03-12 22:48 ` Andreas Rheinhardt
0 siblings, 1 reply; 5+ messages in thread
From: Marth64 @ 2024-03-12 22:41 UTC (permalink / raw)
To: ffmpeg-devel; +Cc: Marth64
I found this code block when looking at this warning thrown in my
compiler (gcc 11.4.0 x86_64-linux-gnu):
```
In function ‘print_buildconf’,
inlined from ‘show_buildconf’ at fftools/opt_common.c:260:5:
fftools/opt_common.c:226:49: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
226 | remove_tilde[sizeof("pkg-config~") - 2] = ' ';
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
fftools/opt_common.c: In function ‘show_buildconf’:
fftools/opt_common.c:214:10: note: at offset [10, 11] into destination object ‘str’ of size 1
214 | char str[] = { FFMPEG_CONFIGURATION };
| ^~~
```
Upon further inspection, I am convinced that remove_tilde does not serve
a functional purpose. There are no other occurences in the FFmpeg
tree via grep, and we are setting a value in it but never using.
The original code traces back to 69cf626f9c1ba29e66ff62e2b835dcfc3031db8d
and even there, I cannot find a purpose for it.
Remove the variable and it's related loop where the assignment occurs,
which resolves the warning.
Signed-off-by: Marth64 <marth64@proxyid.net>
---
fftools/opt_common.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/fftools/opt_common.c b/fftools/opt_common.c
index 947a226d8d..e4a63f565e 100644
--- a/fftools/opt_common.c
+++ b/fftools/opt_common.c
@@ -212,7 +212,7 @@ static void print_buildconf(int flags, int level)
{
const char *indent = flags & INDENT ? " " : "";
char str[] = { FFMPEG_CONFIGURATION };
- char *conflist, *remove_tilde, *splitconf;
+ char *conflist, *splitconf;
// Change all the ' --' strings to '~--' so that
// they can be identified as tokens.
@@ -220,12 +220,6 @@ static void print_buildconf(int flags, int level)
conflist[0] = '~';
}
- // Compensate for the weirdness this would cause
- // when passing 'pkg-config --static'.
- while ((remove_tilde = strstr(str, "pkg-config~")) != NULL) {
- remove_tilde[sizeof("pkg-config~") - 2] = ' ';
- }
-
splitconf = strtok(str, "~");
av_log(NULL, level, "\n%sconfiguration:\n", indent);
while (splitconf != NULL) {
--
2.34.1
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [FFmpeg-devel] [PATCH] fftools/opt_common: remove dead code in print_buildconf()
2024-03-12 22:41 [FFmpeg-devel] [PATCH] fftools/opt_common: remove dead code in print_buildconf() Marth64
@ 2024-03-12 22:48 ` Andreas Rheinhardt
2024-03-12 22:53 ` Marth64
0 siblings, 1 reply; 5+ messages in thread
From: Andreas Rheinhardt @ 2024-03-12 22:48 UTC (permalink / raw)
To: ffmpeg-devel
Marth64:
> I found this code block when looking at this warning thrown in my
> compiler (gcc 11.4.0 x86_64-linux-gnu):
>
> ```
> In function ‘print_buildconf’,
> inlined from ‘show_buildconf’ at fftools/opt_common.c:260:5:
> fftools/opt_common.c:226:49: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
> 226 | remove_tilde[sizeof("pkg-config~") - 2] = ' ';
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
> fftools/opt_common.c: In function ‘show_buildconf’:
> fftools/opt_common.c:214:10: note: at offset [10, 11] into destination object ‘str’ of size 1
> 214 | char str[] = { FFMPEG_CONFIGURATION };
> | ^~~
> ```
>
> Upon further inspection, I am convinced that remove_tilde does not serve
> a functional purpose. There are no other occurences in the FFmpeg
> tree via grep, and we are setting a value in it but never using.
> The original code traces back to 69cf626f9c1ba29e66ff62e2b835dcfc3031db8d
> and even there, I cannot find a purpose for it.
>
> Remove the variable and it's related loop where the assignment occurs,
> which resolves the warning.
>
> Signed-off-by: Marth64 <marth64@proxyid.net>
> ---
> fftools/opt_common.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/fftools/opt_common.c b/fftools/opt_common.c
> index 947a226d8d..e4a63f565e 100644
> --- a/fftools/opt_common.c
> +++ b/fftools/opt_common.c
> @@ -212,7 +212,7 @@ static void print_buildconf(int flags, int level)
> {
> const char *indent = flags & INDENT ? " " : "";
> char str[] = { FFMPEG_CONFIGURATION };
> - char *conflist, *remove_tilde, *splitconf;
> + char *conflist, *splitconf;
>
> // Change all the ' --' strings to '~--' so that
> // they can be identified as tokens.
> @@ -220,12 +220,6 @@ static void print_buildconf(int flags, int level)
> conflist[0] = '~';
> }
>
> - // Compensate for the weirdness this would cause
> - // when passing 'pkg-config --static'.
> - while ((remove_tilde = strstr(str, "pkg-config~")) != NULL) {
> - remove_tilde[sizeof("pkg-config~") - 2] = ' ';
> - }
> -
> splitconf = strtok(str, "~");
> av_log(NULL, level, "\n%sconfiguration:\n", indent);
> while (splitconf != NULL) {
The code block changes str and str is later accessed (via splitconf).
- Andreas
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [FFmpeg-devel] [PATCH] fftools/opt_common: remove dead code in print_buildconf()
2024-03-12 22:48 ` Andreas Rheinhardt
@ 2024-03-12 22:53 ` Marth64
2024-03-12 22:57 ` Andreas Rheinhardt
0 siblings, 1 reply; 5+ messages in thread
From: Marth64 @ 2024-03-12 22:53 UTC (permalink / raw)
To: FFmpeg development discussions and patches
> The code block changes str and str is later accessed (via splitconf).
Sorry, for the lack of awareness, but I am confused how.
strstr() shouldn't modify the string right?
The only change I see is in the unused remove_tilde[]
Thank you, for taking a look and explaining.
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [FFmpeg-devel] [PATCH] fftools/opt_common: remove dead code in print_buildconf()
2024-03-12 22:53 ` Marth64
@ 2024-03-12 22:57 ` Andreas Rheinhardt
2024-03-12 23:02 ` Marth64
0 siblings, 1 reply; 5+ messages in thread
From: Andreas Rheinhardt @ 2024-03-12 22:57 UTC (permalink / raw)
To: ffmpeg-devel
Marth64:
>> The code block changes str and str is later accessed (via splitconf).
> Sorry, for the lack of awareness, but I am confused how.
> strstr() shouldn't modify the string right?
> The only change I see is in the unused remove_tilde[]
>
No, but strstr() returns a pointer pointing into the string
that is used to modify str.
- Andreas
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^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2024-03-12 23:03 UTC | newest]
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2024-03-12 22:41 [FFmpeg-devel] [PATCH] fftools/opt_common: remove dead code in print_buildconf() Marth64
2024-03-12 22:48 ` Andreas Rheinhardt
2024-03-12 22:53 ` Marth64
2024-03-12 22:57 ` Andreas Rheinhardt
2024-03-12 23:02 ` Marth64
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