Re: [PATCH] BaseTools-CLANG38: Add O3 in Dlink2 flag

["Gao, Liming" <liming.gao@intel.com>]

CLANG38 IA32 Arch also requires this change. 

> -----Original Message-----
> From: Shi, Steven
> Sent: Wednesday, August 17, 2016 9:02 PM
> To: edk2-devel@lists.01.org; Gao, Liming <liming.gao@intel.com>
> Cc: ard.biesheuvel@linaro.org; Shi, Steven <steven.shi@intel.com>
> Subject: [PATCH] BaseTools-CLANG38: Add O3 in Dlink2 flag
> 
> CLANG38 build fail after CC_FLAG is added in the link rule.
> This failure is because the CLANG38 enable the LTO through LLVMgold.so
> linker plugin, but the LLVMgold.so plugin cannot accept the clang -Oz
> CC flag as build option. After CC_FLAG is added in the link rule,
> the LLVMgold.so plugin reports linking error. LLVMgold.so only accept
> -O0 ~ -O3, and you can see it in the LLVM gold plugin source code
> in below:
> 
> http://llvm.org/svn/llvm-project/llvm/tags/RELEASE_380/final/tools/gold/
> gold-plugin.cpp line173:
> 
> if (opt[1] < '0' || opt[1] > '3')
>    message(LDPL_FATAL, "Optimization level must be between 0 and 3");
> 
> Add -O3 in the *_CLANG38_X64_DLINK2_FLAGS to override the -Oz flag in
> *_CLANG38_X64_CC_FLAGS to pass LLVMgold.so linking.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Steven Shi <steven.shi@intel.com>
> ---
>  BaseTools/Conf/tools_def.template | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/BaseTools/Conf/tools_def.template
> b/BaseTools/Conf/tools_def.template
> index 974656c..c8e80c9 100755
> --- a/BaseTools/Conf/tools_def.template
> +++ b/BaseTools/Conf/tools_def.template
> @@ -5518,7 +5518,7 @@ RELEASE_CLANG38_IA32_CC_FLAGS       =
> DEF(CLANG38_ALL_CC_FLAGS) -m32 -Oz -flto -
>  DEBUG_CLANG38_X64_CC_FLAGS         = DEF(CLANG38_ALL_CC_FLAGS) -
> m64 "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone -mcmodel=small -
> fpie -Oz -flto DEF(CLANG38_X64_TARGET) -g
>  RELEASE_CLANG38_X64_CC_FLAGS       = DEF(CLANG38_ALL_CC_FLAGS) -
> m64 "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone -mcmodel=small -
> fpie -Oz -flto DEF(CLANG38_X64_TARGET)
>  *_CLANG38_X64_DLINK_FLAGS          = DEF(GCC5_IA32_X64_DLINK_FLAGS) -
> Wl,-Oz -Wl,-melf_x86_64 -Wl,--oformat=elf64-x86-64 -Wl,-pie -
> mcmodel=small
> -*_CLANG38_X64_DLINK2_FLAGS         = DEF(GCC5_X64_DLINK2_FLAGS)
> +*_CLANG38_X64_DLINK2_FLAGS         = DEF(GCC5_X64_DLINK2_FLAGS) -O3
>  *_CLANG38_X64_RC_FLAGS             = DEF(GCC_X64_RC_FLAGS)
>  *_CLANG38_X64_OBJCOPY_FLAGS        =
>  *_CLANG38_X64_NASM_FLAGS           = -f elf64
> --
> 2.7.4