* [PATCH] libstdc++: Fix tr1/8_c_compatibility/cstdio/functions.cc regression with recent glibc
@ 2023-10-12 7:54 Jakub Jelinek
2023-10-12 12:05 ` Jonathan Wakely
0 siblings, 1 reply; 2+ messages in thread
From: Jakub Jelinek @ 2023-10-12 7:54 UTC (permalink / raw)
To: libstdc++, gcc-patches; +Cc: Siddhesh Poyarekar
Hi!
The following testcase started FAILing recently after the
https://sourceware.org/git/?p=glibc.git;a=commit;h=64b1a44183a3094672ed304532bedb9acc707554
glibc change which marked vfscanf with nonnull (1) attribute.
While vfwscanf hasn't been marked similarly (strangely), the patch changes
that too. By using va_arg one hides the value of it from the compiler
(volatile keyword would do too, or making the FILE* stream a function
argument, but then it might need to be guarded by #if or something).
Tested on x86_64-linux, ok for trunk?
2023-10-12 Jakub Jelinek <jakub@redhat.com>
* testsuite/tr1/8_c_compatibility/cstdio/functions.cc (test01):
Initialize stream to va_arg(ap, FILE*) rather than 0.
* testsuite/tr1/8_c_compatibility/cwchar/functions.cc (test01):
Likewise.
--- libstdc++-v3/testsuite/tr1/8_c_compatibility/cstdio/functions.cc.jj 2023-01-16 23:19:06.651711546 +0100
+++ libstdc++-v3/testsuite/tr1/8_c_compatibility/cstdio/functions.cc 2023-10-12 09:46:28.695011763 +0200
@@ -35,7 +35,7 @@ void test01(int dummy, ...)
char* s = 0;
const char* cs = 0;
const char* format = "%i";
- FILE* stream = 0;
+ FILE* stream = va_arg(ap, FILE*);
std::size_t n = 0;
int ret;
--- libstdc++-v3/testsuite/tr1/8_c_compatibility/cwchar/functions.cc.jj 2023-01-16 23:19:06.651711546 +0100
+++ libstdc++-v3/testsuite/tr1/8_c_compatibility/cwchar/functions.cc 2023-10-12 09:46:19.236141897 +0200
@@ -42,7 +42,7 @@ void test01(int dummy, ...)
#endif
#if _GLIBCXX_HAVE_VFWSCANF
- FILE* stream = 0;
+ FILE* stream = va_arg(arg, FILE*);
const wchar_t* format1 = 0;
int ret1;
ret1 = std::tr1::vfwscanf(stream, format1, arg);
Jakub
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] libstdc++: Fix tr1/8_c_compatibility/cstdio/functions.cc regression with recent glibc
2023-10-12 7:54 [PATCH] libstdc++: Fix tr1/8_c_compatibility/cstdio/functions.cc regression with recent glibc Jakub Jelinek
@ 2023-10-12 12:05 ` Jonathan Wakely
0 siblings, 0 replies; 2+ messages in thread
From: Jonathan Wakely @ 2023-10-12 12:05 UTC (permalink / raw)
To: Jakub Jelinek; +Cc: libstdc++, gcc-patches, Siddhesh Poyarekar
[-- Attachment #1: Type: text/plain, Size: 1867 bytes --]
On Thursday, 12 October 2023, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> The following testcase started FAILing recently after the
>
https://sourceware.org/git/?p=glibc.git;a=commit;h=64b1a44183a3094672ed304532bedb9acc707554
> glibc change which marked vfscanf with nonnull (1) attribute.
> While vfwscanf hasn't been marked similarly (strangely), the patch changes
> that too. By using va_arg one hides the value of it from the compiler
> (volatile keyword would do too, or making the FILE* stream a function
> argument, but then it might need to be guarded by #if or something).
>
> Tested on x86_64-linux, ok for trunk?
OK, thanks.
>
> 2023-10-12 Jakub Jelinek <jakub@redhat.com>
>
> * testsuite/tr1/8_c_compatibility/cstdio/functions.cc (test01):
> Initialize stream to va_arg(ap, FILE*) rather than 0.
> * testsuite/tr1/8_c_compatibility/cwchar/functions.cc (test01):
> Likewise.
>
> --- libstdc++-v3/testsuite/tr1/8_c_compatibility/cstdio/functions.cc.jj
2023-01-16 23:19:06.651711546 +0100
> +++ libstdc++-v3/testsuite/tr1/8_c_compatibility/cstdio/functions.cc
2023-10-12 09:46:28.695011763 +0200
> @@ -35,7 +35,7 @@ void test01(int dummy, ...)
> char* s = 0;
> const char* cs = 0;
> const char* format = "%i";
> - FILE* stream = 0;
> + FILE* stream = va_arg(ap, FILE*);
> std::size_t n = 0;
>
> int ret;
> --- libstdc++-v3/testsuite/tr1/8_c_compatibility/cwchar/functions.cc.jj
2023-01-16 23:19:06.651711546 +0100
> +++ libstdc++-v3/testsuite/tr1/8_c_compatibility/cwchar/functions.cc
2023-10-12 09:46:19.236141897 +0200
> @@ -42,7 +42,7 @@ void test01(int dummy, ...)
> #endif
>
> #if _GLIBCXX_HAVE_VFWSCANF
> - FILE* stream = 0;
> + FILE* stream = va_arg(arg, FILE*);
> const wchar_t* format1 = 0;
> int ret1;
> ret1 = std::tr1::vfwscanf(stream, format1, arg);
>
> Jakub
>
>
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2023-10-12 12:05 ` Jonathan Wakely
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