On 05/20/21 04:37, gaoliming wrote: > Laszlo: > Here is the discussion https://edk2.groups.io/g/devel/message/75299. > Now, some uninitialized warning can't be detected on GCC5 tool chain, but > can be detected on GCC49 tool chain. > Edk2 CI only covers GCC5 tool chain. So, the merged code may impact GCC49 > build. > I add this option to expose such uninitialized warning in GCC5 tool chain > and increase GCC5 tool chain coverage. > > And, this is gcc issue https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90844 > > Yes. This change will expose some existing issues. I will include more > detail in the commit message for this change.
Great, thanks for the info. Can you please include the reference https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90844 in the commit message? Acked-by: Laszlo Ersek <ler...@redhat.com> Thanks! Laszlo > > Thanks > Liming >> -----邮件原件----- >> 发件人: Laszlo Ersek <ler...@redhat.com> >> 发送时间: 2021年5月19日 15:23 >> 收件人: devel@edk2.groups.io; gaolim...@byosoft.com.cn >> 抄送: Sergei Dmitrouk <ser...@posteo.net>; Bob Feng >> <bob.c.f...@intel.com>; Ard Biesheuvel <ardb+tianoc...@kernel.org> >> 主题: Re: [edk2-devel] [PATCH] BaseTools: Add -ffat-lto-objects option in >> GCC5 tool chain >> >> Hi Liming, >> >> On 05/19/21 04:27, gaoliming wrote: >>> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3403 >>> >>> This option can trig the uninitialized warning when lto is enabled. >>> The image size data is also collected for OVMF. There is no impact. >>> >>> Cc: Sergei Dmitrouk <ser...@posteo.net> >>> Cc: Bob Feng <bob.c.f...@intel.com> >>> Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org> >>> Signed-off-by: Liming Gao <gaolim...@byosoft.com.cn> >>> --- >>> BaseTools/Conf/tools_def.template | 16 ++++++++-------- >>> 1 file changed, 8 insertions(+), 8 deletions(-) >> >> I've now read the documentation on "-ffat-lto-objects", and I agree that >> it should not affect the final module executable sizes. >> >> However, I don't understand how this option *helps*. You mention >> "uninitialized warning". I find nothing related to that in the >> documentation. >> >> According to the documentation, "fat" LTO objects include both object >> code and intermediate language (GIMPLE) bytecode. Such objects can then >> be linked with, or without, link-time (= interprocedural) optimization. >> As I understand the documentation, "fat" LTO objects only make a >> difference if there are parts of the toolchain that are themselves >> unaware of LTO, and so need the GIMPLE bytecode to be present in the >> object files. >> >> I *guess* that this is the situation that we have in edk2 -- is there >> perhaps something in our toolchain(s) that does not "notice" LTO without >> "fat" LTO objects, and therefore we fail to emit a warning? Because, >> without LTO, we don't notice that an initialization is missing? >> >> This is too speculative. The commit message should please include more >> details. I'd like to understand what code in edk2 is affected, what the >> specific warning is, what the problematic component in the toolchain is >> (i.e., what tool requires GIMPLE bytecode to be present in the object file). >> >> Thanks, >> Laszlo >> >> >> >>> >>> diff --git a/BaseTools/Conf/tools_def.template >> b/BaseTools/Conf/tools_def.template >>> index 498696e583..aad5297385 100755 >>> --- a/BaseTools/Conf/tools_def.template >>> +++ b/BaseTools/Conf/tools_def.template >>> @@ -2315,10 +2315,10 @@ RELEASE_GCC49_AARCH64_DLINK_XIPFLAGS >> = -z common-page-size=0x20 >>> *_GCC5_IA32_OBJCOPY_FLAGS = >>> *_GCC5_IA32_NASM_FLAGS = -f elf32 >>> >>> - DEBUG_GCC5_IA32_CC_FLAGS = DEF(GCC5_IA32_CC_FLAGS) >> -flto -Os >>> + DEBUG_GCC5_IA32_CC_FLAGS = DEF(GCC5_IA32_CC_FLAGS) >> -ffat-lto-objects -flto -Os >>> DEBUG_GCC5_IA32_DLINK_FLAGS = >> DEF(GCC5_IA32_X64_DLINK_FLAGS) -flto -Os >> -Wl,-m,elf_i386,--oformat=elf32-i386 >>> >>> -RELEASE_GCC5_IA32_CC_FLAGS = DEF(GCC5_IA32_CC_FLAGS) >> -flto -Os -Wno-unused-but-set-variable -Wno-unused-const-variable >>> +RELEASE_GCC5_IA32_CC_FLAGS = DEF(GCC5_IA32_CC_FLAGS) >> -ffat-lto-objects -flto -Os -Wno-unused-but-set-variable >> -Wno-unused-const-variable >>> RELEASE_GCC5_IA32_DLINK_FLAGS = >> DEF(GCC5_IA32_X64_DLINK_FLAGS) -flto -Os >> -Wl,-m,elf_i386,--oformat=elf32-i386 >>> >>> NOOPT_GCC5_IA32_CC_FLAGS = DEF(GCC5_IA32_CC_FLAGS) >> -O0 >>> @@ -2347,10 +2347,10 @@ RELEASE_GCC5_IA32_DLINK_FLAGS = >> DEF(GCC5_IA32_X64_DLINK_FLAGS) -flto -Os -Wl, >>> *_GCC5_X64_OBJCOPY_FLAGS = >>> *_GCC5_X64_NASM_FLAGS = -f elf64 >>> >>> - DEBUG_GCC5_X64_CC_FLAGS = DEF(GCC5_X64_CC_FLAGS) >> -flto -DUSING_LTO -Os >>> + DEBUG_GCC5_X64_CC_FLAGS = DEF(GCC5_X64_CC_FLAGS) >> -ffat-lto-objects -flto -DUSING_LTO -Os >>> DEBUG_GCC5_X64_DLINK_FLAGS = >> DEF(GCC5_X64_DLINK_FLAGS) -flto -Os >>> >>> -RELEASE_GCC5_X64_CC_FLAGS = DEF(GCC5_X64_CC_FLAGS) >> -flto -DUSING_LTO -Os -Wno-unused-but-set-variable >> -Wno-unused-const-variable >>> +RELEASE_GCC5_X64_CC_FLAGS = DEF(GCC5_X64_CC_FLAGS) >> -ffat-lto-objects -flto -DUSING_LTO -Os -Wno-unused-but-set-variable >> -Wno-unused-const-variable >>> RELEASE_GCC5_X64_DLINK_FLAGS = DEF(GCC5_X64_DLINK_FLAGS) >> -flto -Os >>> >>> NOOPT_GCC5_X64_CC_FLAGS = DEF(GCC5_X64_CC_FLAGS) >> -O0 >>> @@ -2382,10 +2382,10 @@ RELEASE_GCC5_X64_DLINK_FLAGS = >> DEF(GCC5_X64_DLINK_FLAGS) -flto -Os >>> *_GCC5_ARM_VFRPP_FLAGS = $(ARCHCC_FLAGS) >> $(PLATFORM_FLAGS) DEF(GCC_VFRPP_FLAGS) >>> *_GCC5_ARM_CC_XIPFLAGS = >> DEF(GCC5_ARM_CC_XIPFLAGS) >>> >>> - DEBUG_GCC5_ARM_CC_FLAGS = DEF(GCC5_ARM_CC_FLAGS) >> -flto -Wno-unused-but-set-variable -Wno-unused-const-variable >>> + DEBUG_GCC5_ARM_CC_FLAGS = DEF(GCC5_ARM_CC_FLAGS) >> -ffat-lto-objects -flto -Wno-unused-but-set-variable >> -Wno-unused-const-variable >>> DEBUG_GCC5_ARM_DLINK_FLAGS = >> DEF(GCC5_ARM_DLINK_FLAGS) -flto -Os >> -L$(WORKSPACE)/ArmPkg/Library/GccLto -llto-arm >> -Wl,-plugin-opt=-pass-through=-llto-arm >>> >>> -RELEASE_GCC5_ARM_CC_FLAGS = DEF(GCC5_ARM_CC_FLAGS) >> -flto -Wno-unused-but-set-variable -Wno-unused-const-variable >>> +RELEASE_GCC5_ARM_CC_FLAGS = DEF(GCC5_ARM_CC_FLAGS) >> -ffat-lto-objects -flto -Wno-unused-but-set-variable >> -Wno-unused-const-variable >>> RELEASE_GCC5_ARM_DLINK_FLAGS = >> DEF(GCC5_ARM_DLINK_FLAGS) -flto -Os >> -L$(WORKSPACE)/ArmPkg/Library/GccLto -llto-arm >> -Wl,-plugin-opt=-pass-through=-llto-arm >>> >>> NOOPT_GCC5_ARM_CC_FLAGS = DEF(GCC5_ARM_CC_FLAGS) >> -O0 >>> @@ -2416,11 +2416,11 @@ RELEASE_GCC5_ARM_DLINK_FLAGS = >> DEF(GCC5_ARM_DLINK_FLAGS) -flto -Os -L$(WORKS >>> *_GCC5_AARCH64_VFRPP_FLAGS = $(ARCHCC_FLAGS) >> $(PLATFORM_FLAGS) DEF(GCC_VFRPP_FLAGS) >>> *_GCC5_AARCH64_CC_XIPFLAGS = >> DEF(GCC5_AARCH64_CC_XIPFLAGS) >>> >>> - DEBUG_GCC5_AARCH64_CC_FLAGS = >> DEF(GCC5_AARCH64_CC_FLAGS) -flto -Wno-unused-but-set-variable >> -Wno-unused-const-variable >>> + DEBUG_GCC5_AARCH64_CC_FLAGS = >> DEF(GCC5_AARCH64_CC_FLAGS) -ffat-lto-objects -flto >> -Wno-unused-but-set-variable -Wno-unused-const-variable >>> DEBUG_GCC5_AARCH64_DLINK_FLAGS = >> DEF(GCC5_AARCH64_DLINK_FLAGS) -flto -Os >> -L$(WORKSPACE)/ArmPkg/Library/GccLto -llto-aarch64 >> -Wl,-plugin-opt=-pass-through=-llto-aarch64 -Wno-lto-type-mismatch >>> DEBUG_GCC5_AARCH64_DLINK_XIPFLAGS = -z >> common-page-size=0x20 >>> >>> -RELEASE_GCC5_AARCH64_CC_FLAGS = >> DEF(GCC5_AARCH64_CC_FLAGS) -flto -Wno-unused-but-set-variable >> -Wno-unused-const-variable >>> +RELEASE_GCC5_AARCH64_CC_FLAGS = >> DEF(GCC5_AARCH64_CC_FLAGS) -ffat-lto-objects -flto >> -Wno-unused-but-set-variable -Wno-unused-const-variable >>> RELEASE_GCC5_AARCH64_DLINK_FLAGS = >> DEF(GCC5_AARCH64_DLINK_FLAGS) -flto -Os >> -L$(WORKSPACE)/ArmPkg/Library/GccLto -llto-aarch64 >> -Wl,-plugin-opt=-pass-through=-llto-aarch64 -Wno-lto-type-mismatch >>> RELEASE_GCC5_AARCH64_DLINK_XIPFLAGS = -z >> common-page-size=0x20 >>> >>> > > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. 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