For the variadic function error with AMD64 abi and windows calling convention on
64bits x86, I find it has been tracked in Bug 20847
(https://llvm.org/bugs/show_bug.cgi?id=20847)
(http://reviews.llvm.org/D1622#inline-9345). Do we still plan to fix it?
You know, I meet exactly same va_arg mistake with llvm3.7 when I enable the Uefi
firmware (http://www.uefi.org/) build with clang. The ms_abi is the Uefi
firmware binary module standard interface. I really hope this bug fix can been
checked in as soon as possible. If we cannot fix it in short time, could we
offer a temporary fix patch based on llvm3.7?
Steven Shi
Intel\SSG\STO\UEFI Firmware
Tel: +86 021-61166522
iNet: 821-6522
From: Shi, Steven
Sent: Thursday, January 07, 2016 11:07 PM
To: 'cfe-dev at lists.llvm.org'
Subject: Is it a va_arg bug in clang?
Hello,
I'm trying to use the clang3.7 to compile 64bits x86 code with Microsoft
ABI in Ubuntu 64bit, but I find the va_arg get the wrong variable argument from
the va_list. Below is my test code.
#include <stdio.h>
#include <stdarg.h>
void
__attribute__((ms_abi))
Foo_va_list (
int VaNum,
const char *Format,
...
)
{
va_list Marker;
long long Value;
va_start (Marker, Format);
for (int i = 0; i < VaNum; i++ ) {
Value = va_arg (Marker, int);
printf("Value = 0x%llx\n", Value);
}
va_end (Marker);
}
int main()
{
Foo_va_list (16, "0123456789abcdef= %x%x%x%x%x%x%x%x%x%x%x%x%x%x%x%x
\n", 0,1,2,3,4,5,6,7,8,9,0xa,0xb,0xc,0xd,0xe,0xf);
return 0;
}
The expected output are:
Value = 0x0
Value = 0x1
Value = 0x2
Value = 0x3
Value = 0x4
Value = 0x5
Value = 0x6
Value = 0x7
Value = 0x8
Value = 0x9
Value = 0xa
Value = 0xb
Value = 0xc
Value = 0xd
Value = 0xe
Value = 0xf
But the real output are:
Value = 0x0
Value = 0x1
Value = 0x2
Value = 0x3
Value = 0x4
Value = 0x5
Value = 0x0
Value = 0x1
Value = 0x2
Value = 0x3
Value = 0x4
Value = 0x5
Value = 0x6
Value = 0x7
Value = 0x8
Value = 0x9
After I remove the Microsoft ABI definition __attribute__((ms_abi)) above
Foo_va_list () in the code, the output will become correct. I find GCC also have
similar wrong behavior with __attribute__((ms_abi)). I don't know how to
make the __attribute__((ms_abi)) work correctly with va_arg. I appreciate if
any suggestion.
Steven Shi
Intel\SSG\STO\UEFI Firmware
Tel: +86 021-61166522
iNet: 821-6522
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Richard Smith via llvm-dev
2016-Jan-08 19:26 UTC
[llvm-dev] [cfe-dev] Is it a va_arg bug in clang?
On Thu, Jan 7, 2016 at 11:15 PM, Shi, Steven via cfe-dev < cfe-dev at lists.llvm.org> wrote:> For the variadic function error with AMD64 abi and windows calling > convention on 64bits x86, I find it has been tracked in Bug 20847 ( > https://llvm.org/bugs/show_bug.cgi?id=20847) ( > http://reviews.llvm.org/D1622#inline-9345). Do we still plan to fix it? > > > > You know, I meet exactly same va_arg mistake with llvm3.7 when I enable > the Uefi firmware (http://www.uefi.org/) build with clang. The ms_abi is > the Uefi firmware binary module standard interface. I really hope this bug > fix can been checked in as soon as possible. If we cannot fix it in short > time, could we offer a temporary fix patch based on llvm3.7? >This is already fixed in clang trunk. Your code is rejected as follows: <stdin>:15:17: error: 'va_start' used in Win64 ABI function va_start (Marker, Format); ^ You need to use __builtin_ms_va_list, __builtin_ms_va_start, __builtin_ms_va_end to use ms_abi varargs semantics. (In particular, note that __builtin_ms_va_list is a different type from va_list, so this can't "just work" in the way you expect it to.)> *Steven Shi* > > *Intel\SSG\STO\UEFI Firmware* > > > > Tel: +86 021-61166522 > > iNet: 821-6522 > > > > *From:* Shi, Steven > *Sent:* Thursday, January 07, 2016 11:07 PM > *To:* 'cfe-dev at lists.llvm.org' > *Subject:* Is it a va_arg bug in clang? > > > > Hello, > > I’m trying to use the clang3.7 to compile 64bits x86 code with Microsoft > ABI in Ubuntu 64bit, but I find the va_arg get the wrong variable argument > from the va_list. Below is my test code. > > > > #include <stdio.h> > > #include <stdarg.h> > > > > void > > __attribute__((ms_abi)) > > Foo_va_list ( > > int VaNum, > > const char *Format, > > ... > > ) > > { > > va_list Marker; > > long long Value; > > > > va_start (Marker, Format); > > for (int i = 0; i < VaNum; i++ ) { > > Value = va_arg (Marker, int); > > printf("Value = 0x%llx\n", Value); > > } > > va_end (Marker); > > } > > > > > > int main() > > { > > Foo_va_list (16, "0123456789abcdef= %x%x%x%x%x%x%x%x%x%x%x%x%x%x%x%x > \n", 0,1,2,3,4,5,6,7,8,9,0xa,0xb,0xc,0xd,0xe,0xf); > > return 0; > > } > > > > The expected output are: > > Value = 0x0 > > Value = 0x1 > > Value = 0x2 > > Value = 0x3 > > Value = 0x4 > > Value = 0x5 > > Value = 0x6 > > Value = 0x7 > > Value = 0x8 > > Value = 0x9 > > Value = 0xa > > Value = 0xb > > Value = 0xc > > Value = 0xd > > Value = 0xe > > Value = 0xf > > > > But the real output are: > > Value = 0x0 > > Value = 0x1 > > Value = 0x2 > > Value = 0x3 > > Value = 0x4 > > Value = 0x5 > > Value = 0x0 > > Value = 0x1 > > Value = 0x2 > > Value = 0x3 > > Value = 0x4 > > Value = 0x5 > > Value = 0x6 > > Value = 0x7 > > Value = 0x8 > > Value = 0x9 > > > > After I remove the Microsoft ABI definition __attribute__((ms_abi)) above > Foo_va_list () in the code, the output will become correct. I find GCC > also have similar wrong behavior with __attribute__((ms_abi)). I don’t know > how to make the __attribute__((ms_abi)) work correctly with va_arg. I > appreciate if any suggestion. > > > > > > > > > > > > > > *Steven Shi* > > *Intel\SSG\STO\UEFI Firmware* > > > > Tel: +86 021-61166522 > > iNet: 821-6522 > > > > _______________________________________________ > cfe-dev mailing list > cfe-dev at lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20160108/e3f1c9df/attachment.html>
Shi, Steven via llvm-dev
2016-Jan-09 03:15 UTC
[llvm-dev] [cfe-dev] Is it a va_arg bug in clang?
Hi Richard,
Thank you for the info. I build my code in Ubuntu-64bits with simply commands:
“clang X64.c”, then run “./a.out” to see the output. If I replace my va_list,
va_start, va_arg va_end with __builtin_ms_va_list, __builtin_ms_va_start,
__builtin_ms_va_arg, __builtin_ms_va_end, my code will build fail in Ubuntu with
below message. Do you suggest I should build it in windows and not in Linux? Or
did I miss any build option here? Appreciate if you could let me know the
correct build steps.
jshi19 at jshi19-Intel:/mnt/disk3$ clang X64.c
X64.c:12:2: error: unknown type name '__builtin_ms_va_list'; did you
mean
'__builtin_va_list'?
__builtin_ms_va_list Marker;
^~~~~~~~~~~~~~~~~~~~
__builtin_va_list
note: '__builtin_va_list' declared here
X64.c:15:2: error: use of unknown builtin '__builtin_ms_va_start'
[-Wimplicit-function-declaration]
__builtin_ms_va_start (Marker, Format);
^
X64.c:17:11: error: use of unknown builtin '__builtin_ms_va_arg'
[-Wimplicit-function-declaration]
Value = __builtin_ms_va_arg (Marker, int);
^
X64.c:17:11: note: did you mean '__builtin_ms_va_start'?
X64.c:15:2: note: '__builtin_ms_va_start' declared here
__builtin_ms_va_start (Marker, Format);
^
X64.c:17:40: error: expected expression
Value = __builtin_ms_va_arg (Marker, int);
^
X64.c:20:2: error: use of unknown builtin '__builtin_ms_va_end'
[-Wimplicit-function-declaration]
__builtin_ms_va_end (Marker);
^
X64.c:20:2: note: did you mean '__builtin_ms_va_arg'?
X64.c:17:11: note: '__builtin_ms_va_arg' declared here
Value = __builtin_ms_va_arg (Marker, int);
^
5 errors generated.
Steven Shi
Intel\SSG\STO\UEFI Firmware
Tel: +86 021-61166522
iNet: 821-6522
From: metafoo at gmail.com [mailto:metafoo at gmail.com] On Behalf Of Richard
Smith
Sent: Saturday, January 09, 2016 3:26 AM
To: Shi, Steven
Cc: cfe-dev at lists.llvm.org; llvm-dev at lists.llvm.org
Subject: Re: [cfe-dev] Is it a va_arg bug in clang?
On Thu, Jan 7, 2016 at 11:15 PM, Shi, Steven via cfe-dev <cfe-dev at
lists.llvm.org<mailto:cfe-dev at lists.llvm.org>> wrote:
For the variadic function error with AMD64 abi and windows calling convention on
64bits x86, I find it has been tracked in Bug 20847
(https://llvm.org/bugs/show_bug.cgi?id=20847)
(http://reviews.llvm.org/D1622#inline-9345). Do we still plan to fix it?
You know, I meet exactly same va_arg mistake with llvm3.7 when I enable the Uefi
firmware (http://www.uefi.org/) build with clang. The ms_abi is the Uefi
firmware binary module standard interface. I really hope this bug fix can been
checked in as soon as possible. If we cannot fix it in short time, could we
offer a temporary fix patch based on llvm3.7?
This is already fixed in clang trunk. Your code is rejected as follows:
<stdin>:15:17: error: 'va_start' used in Win64 ABI function
va_start (Marker, Format);
^
You need to use __builtin_ms_va_list, __builtin_ms_va_start, __builtin_ms_va_end
to use ms_abi varargs semantics. (In particular, note that __builtin_ms_va_list
is a different type from va_list, so this can't "just work" in the
way you expect it to.)
Steven Shi
Intel\SSG\STO\UEFI Firmware
Tel: +86 021-61166522<tel:%2B86%20021-61166522>
iNet: 821-6522
From: Shi, Steven
Sent: Thursday, January 07, 2016 11:07 PM
To: 'cfe-dev at lists.llvm.org<mailto:cfe-dev at lists.llvm.org>'
Subject: Is it a va_arg bug in clang?
Hello,
I’m trying to use the clang3.7 to compile 64bits x86 code with Microsoft ABI in
Ubuntu 64bit, but I find the va_arg get the wrong variable argument from the
va_list. Below is my test code.
#include <stdio.h>
#include <stdarg.h>
void
__attribute__((ms_abi))
Foo_va_list (
int VaNum,
const char *Format,
...
)
{
va_list Marker;
long long Value;
va_start (Marker, Format);
for (int i = 0; i < VaNum; i++ ) {
Value = va_arg (Marker, int);
printf("Value = 0x%llx\n", Value);
}
va_end (Marker);
}
int main()
{
Foo_va_list (16, "0123456789abcdef= %x%x%x%x%x%x%x%x%x%x%x%x%x%x%x%x
\n", 0,1,2,3,4,5,6,7,8,9,0xa,0xb,0xc,0xd,0xe,0xf);
return 0;
}
The expected output are:
Value = 0x0
Value = 0x1
Value = 0x2
Value = 0x3
Value = 0x4
Value = 0x5
Value = 0x6
Value = 0x7
Value = 0x8
Value = 0x9
Value = 0xa
Value = 0xb
Value = 0xc
Value = 0xd
Value = 0xe
Value = 0xf
But the real output are:
Value = 0x0
Value = 0x1
Value = 0x2
Value = 0x3
Value = 0x4
Value = 0x5
Value = 0x0
Value = 0x1
Value = 0x2
Value = 0x3
Value = 0x4
Value = 0x5
Value = 0x6
Value = 0x7
Value = 0x8
Value = 0x9
After I remove the Microsoft ABI definition __attribute__((ms_abi)) above
Foo_va_list () in the code, the output will become correct. I find GCC also have
similar wrong behavior with __attribute__((ms_abi)). I don’t know how to make
the __attribute__((ms_abi)) work correctly with va_arg. I appreciate if any
suggestion.
Steven Shi
Intel\SSG\STO\UEFI Firmware
Tel: +86 021-61166522<tel:%2B86%20021-61166522>
iNet: 821-6522
_______________________________________________
cfe-dev mailing list
cfe-dev at lists.llvm.org<mailto:cfe-dev at lists.llvm.org>
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
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