Re: [Patch 1/2] BaseTools: Add -D NO_MSABI_VARGS to X64 XCODE5 CC_FLAGS

[Andrew Fish <afish@apple.com>]

> On May 19, 2017, at 5:49 AM, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> 
> On 19 May 2017 at 07:52, Michael Kinney <michael.d.kinney@intel.com <mailto:michael.d.kinney@intel.com>> wrote:
>> https://bugzilla.tianocore.org/show_bug.cgi?id=561
>> 
>> Update BaseTools/Conf/tools_def.template to add the define
>> 
>> -D NO_MSABI_VAARGS
>> 
>> To CC_FLAGS for X64 XCODE5 builds.
>> 
>> The llvm/clang compiler used in XCODE5 builds supports the
>> _ms_ versions of the vararg builtins, but the compiler
>> generates build errors.
>> 
>> The recommendation from the XCODE5 experts is to never use
>> the _ms_ version of the vararg builtins.  The define
>> NO_MSABI_VARARGS is already supported in MdePkg/Include/Base.h
>> and forces the use the standard vararg builtins.
>> 
> 
> Are such builds compliant with the UEFI spec?
> 

Ard I think you are confusing implementation and architecture. The UEFI Spec quotes an ABI, and __builtin_ms_* is a non standard compiler extension. 

Clang was designed to be a cross compiler and for X64 (x86_64) we set the arch to clang via -target x86_64-pc-win32-macho. Basically this tells clang it is an x86_64 (X64) arch, with a Windows ABI (EFI ABI), and produce a Mach-O Executable (for debugging). So the default var args builtin does the right thing for the EFI ABI, and __builtin_ms_* is not supported. The x86_64-pc-win32-macho triple is only used for EFI and when I talked to the clang folks they were like why do you need __builtin_ms_* when it is the same as __builtin_*, please fix your include files. 

Thanks,

Andrew Fish

>> Cc: Andrew Fish <afish@apple.com>
>> Cc: Liming Gao <liming.gao@intel.com>
>> Contributed-under: TianoCore Contribution Agreement 1.0
>> Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
>> ---
>> BaseTools/Conf/tools_def.template | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>> 
>> diff --git a/BaseTools/Conf/tools_def.template b/BaseTools/Conf/tools_def.template
>> index 427ef1b..ed9e834 100755
>> --- a/BaseTools/Conf/tools_def.template
>> +++ b/BaseTools/Conf/tools_def.template
>> @@ -7494,9 +7494,9 @@ RELEASE_XCODE5_X64_ASM_FLAGS  = -arch x86_64
>> *_XCODE5_*_VFRPP_FLAGS      = -x c -E -P -DVFRCOMPILE -include $(DEST_DIR_DEBUG)/$(MODULE_NAME)StrDefs.h
>> 
>> 
>> -  DEBUG_XCODE5_X64_CC_FLAGS   = -target x86_64-pc-win32-macho -c -g -Os       -Wall -Werror -Wextra -include AutoGen.h -funsigned-char -fno-ms-extensions -fno-stack-protector -fno-builtin -fshort-wchar -mno-implicit-float -mms-bitfields -Wno-unused-parameter -Wno-missing-braces -Wno-missing-field-initializers -Wno-tautological-compare -Wno-sign-compare -ftrap-function=undefined_behavior_has_been_optimized_away_by_clang $(PLATFORM_FLAGS)
>> -  NOOPT_XCODE5_X64_CC_FLAGS   = -target x86_64-pc-win32-macho -c -g -O0       -Wall -Werror -Wextra -include AutoGen.h -funsigned-char -fno-ms-extensions -fno-stack-protector -fno-builtin -fshort-wchar -mno-implicit-float -mms-bitfields -Wno-unused-parameter -Wno-missing-braces -Wno-missing-field-initializers -Wno-tautological-compare -Wno-sign-compare -ftrap-function=undefined_behavior_has_been_optimized_away_by_clang $(PLATFORM_FLAGS)
>> -RELEASE_XCODE5_X64_CC_FLAGS   = -target x86_64-pc-win32-macho -c    -Os       -Wall -Werror -Wextra -include AutoGen.h -funsigned-char -fno-ms-extensions -fno-stack-protector -fno-builtin -fshort-wchar -mno-implicit-float -mms-bitfields -Wno-unused-parameter -Wno-missing-braces -Wno-missing-field-initializers -Wno-tautological-compare -Wno-sign-compare -ftrap-function=undefined_behavior_has_been_optimized_away_by_clang $(PLATFORM_FLAGS)
>> +  DEBUG_XCODE5_X64_CC_FLAGS   = -target x86_64-pc-win32-macho -c -g -Os       -Wall -Werror -Wextra -include AutoGen.h -funsigned-char -fno-ms-extensions -fno-stack-protector -fno-builtin -fshort-wchar -mno-implicit-float -mms-bitfields -Wno-unused-parameter -Wno-missing-braces -Wno-missing-field-initializers -Wno-tautological-compare -Wno-sign-compare -ftrap-function=undefined_behavior_has_been_optimized_away_by_clang -D NO_MSABI_VA_FUNCS $(PLATFORM_FLAGS)
>> +  NOOPT_XCODE5_X64_CC_FLAGS   = -target x86_64-pc-win32-macho -c -g -O0       -Wall -Werror -Wextra -include AutoGen.h -funsigned-char -fno-ms-extensions -fno-stack-protector -fno-builtin -fshort-wchar -mno-implicit-float -mms-bitfields -Wno-unused-parameter -Wno-missing-braces -Wno-missing-field-initializers -Wno-tautological-compare -Wno-sign-compare -ftrap-function=undefined_behavior_has_been_optimized_away_by_clang -D NO_MSABI_VA_FUNCS $(PLATFORM_FLAGS)
>> +RELEASE_XCODE5_X64_CC_FLAGS   = -target x86_64-pc-win32-macho -c    -Os       -Wall -Werror -Wextra -include AutoGen.h -funsigned-char -fno-ms-extensions -fno-stack-protector -fno-builtin -fshort-wchar -mno-implicit-float -mms-bitfields -Wno-unused-parameter -Wno-missing-braces -Wno-missing-field-initializers -Wno-tautological-compare -Wno-sign-compare -ftrap-function=undefined_behavior_has_been_optimized_away_by_clang -D NO_MSABI_VA_FUNCS $(PLATFORM_FLAGS)
>> 
>> *_XCODE5_*_ASLCC_FLAGS      = -x c -save-temps -g -O0 -fshort-wchar -fno-strict-aliasing -Wall -Werror -Wno-missing-braces -c -include AutoGen.h
>> *_XCODE5_*_ASLDLINK_FLAGS   = -e _ReferenceAcpiTable -preload -segalign 0x20  -pie -seg1addr 0x240 -read_only_relocs suppress -map $(DEST_DIR_DEBUG)/$(BASE_NAME).map
>> --
>> 2.6.3.windows.1
>> 
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