Re: [edk2-devel] [PATCH] BaseTools/tools_def.txt: Add -march=x86-64 for X64 CLANG and GCC targets

["dann frazier" <dann.frazier@canonical.com>]

Hi Pedro,

Yeah, apparently GCC didn't document it until 8.1.0:
  https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=c7cb6c178884
But it appears to have been introduced far earlier - best I can tell,
in 4.1:
  https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=3fec9fa9b726
It seems to be unrelated to the introduction of x86-64-v*, which was
in 11.1:
  https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=324bec558e95

I don't speak GCC source fluently, so it's possible I could've
misinterpreted those commits, so I did some testing. Ubuntu 16.04 had
compilers based on GCC 5.4.0 and clang 4.0. Both accept -march=x86-64:

$ gcc --version
gcc (Ubuntu 5.4.0-6ubuntu1~16.04.12) 5.4.0 20160609
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ gcc hello.c -o hello -march=x86-64

$ clang-4.0 --version
clang version 4.0.0-1ubuntu1~16.04.2 (tags/RELEASE_400/rc1)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
$ clang-4.0 hello.c -o hello -march=x86-64
$

Going all the way back to Ubuntu 12.04, which included compilers based
on GCC 4.4.7 and clang 3.3:

$ gcc-4.4 --version
gcc-4.4 (Ubuntu/Linaro 4.4.7-1ubuntu2) 4.4.7
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ gcc-4.4 test.c -o test -march=x86-64
$ clang --version
Ubuntu clang version 3.3-5ubuntu4~precise1 (branches/release_33) (based on LLVM 3.3)
Target: x86_64-pc-linux-gnu
Thread model: posix
$ clang test.c -o test -march=x86-64
$ 

  -dann
  
On Thu, Jun 30, 2022 at 02:05:52AM +0100, Pedro Falcato wrote:
> GCC 5.4 documentation (
> https://gcc.gnu.org/onlinedocs/gcc-5.4.0/gcc/x86-Options.html#x86-Options)
> doesn't include x86-64. I assume that specific option was added somewhere
> in the last 2-3 years when this x86-64-v* concept was added?
> 
> I went looking around in linux and they don't seem to specify anything of
> sorts either.
> 
> I can't speak for ARM but for IA32 it's pretty logic: the Pentium 1 (i586)
> was the first processor with CPUID, RDTSC, RD/WRMSR, etc. Essentials for
> firmware code that will never really even run on a processor that old.
> 
> On Thu, Jun 30, 2022 at 12:25 AM dann frazier <dann.frazier@canonical.com>
> wrote:
> 
> > On Wed, Jun 29, 2022 at 11:06:01PM +0100, Pedro Falcato wrote:
> > > This may be a strong opinion but I would consider toolchains that
> > > explicitly change the default -march from the well understood x86-64
> > (which
> > > all 64-bit processors support) to be totally broken. If a distro wants to
> > > switch the -march for the packages, override CFLAGS :)
> >
> > Opinion noted. But is there a downside to edk2 being explicit about
> > its target CPU level on x86-64, given it already does so for IA32 and
> > ARM?
> >
> >   -dann
> >
> > > On Wed, Jun 29, 2022 at 10:57 PM dann frazier <
> > dann.frazier@canonical.com>
> > > wrote:
> > >
> > > > Ping on this. Would it be more palatable if I limited the change only
> > > > to tested toolchains (gcc/clang)? Alternatively, is there a way to
> > > > submit this code to CI to verify the !(gcc|clang) variants?
> > > >
> > > >   -dann
> > > >
> > > > On Fri, Jun 10, 2022 at 12:09:18PM -0600, dann frazier wrote:
> > > > > From: dann frazier <dann.frazier@canonical.com>
> > > > >
> > > > > Some Linux distributions are experimenting with builds that target a
> > > > > higher x86-64 psABI, such as x86-64-v3. To avoid inheriting these
> > > > > compiler defaults in edk2 builds, and therefore breaking
> > compatibility
> > > > > with machines using older CPUs, explicitly target the generic x86-64
> > > > > psABI. This is similar to how we explicitly specify the cpu type for
> > > > > some other architectures (-march=i586 for IA32, -march=armv7-a for
> > ARM).
> > > > >
> > > > > Spot tested with OVMF builds using GCC5 and CLANG38.
> > > > >
> > > > > Signed-off-by: dann frazier <dann.frazier@canonical.com>
> > > > > ---
> > > > >  BaseTools/Conf/tools_def.template | 20 ++++++++++----------
> > > > >  1 file changed, 10 insertions(+), 10 deletions(-)
> > > > >
> > > > > diff --git a/BaseTools/Conf/tools_def.template
> > > > b/BaseTools/Conf/tools_def.template
> > > > > index adcd23f727..569d16fb3e 100755
> > > > > --- a/BaseTools/Conf/tools_def.template
> > > > > +++ b/BaseTools/Conf/tools_def.template
> > > > > @@ -1885,7 +1885,7 @@ DEFINE GCC_DEPS_FLAGS              = -MMD -MF
> > > > $@.deps
> > > > >  DEFINE GCC48_ALL_CC_FLAGS            = DEF(GCC_ALL_CC_FLAGS)
> > > > -ffunction-sections -fdata-sections
> > -DSTRING_ARRAY_NAME=$(BASE_NAME)Strings
> > > > >  DEFINE GCC48_IA32_X64_DLINK_COMMON   = -nostdlib
> > > > -Wl,-n,-q,--gc-sections -z common-page-size=0x20
> > > > >  DEFINE GCC48_IA32_CC_FLAGS           = DEF(GCC48_ALL_CC_FLAGS) -m32
> > > > -march=i586 -malign-double -fno-stack-protector -D EFI32
> > > > -fno-asynchronous-unwind-tables -Wno-address
> > > > > -DEFINE GCC48_X64_CC_FLAGS            = DEF(GCC48_ALL_CC_FLAGS) -m64
> > > > -fno-stack-protector "-DEFIAPI=__attribute__((ms_abi))"
> > > > -maccumulate-outgoing-args -mno-red-zone -Wno-address -mcmodel=small
> > -fpie
> > > > -fno-asynchronous-unwind-tables -Wno-address
> > > > > +DEFINE GCC48_X64_CC_FLAGS            = DEF(GCC48_ALL_CC_FLAGS) -m64
> > > > -march=x86-64 -fno-stack-protector "-DEFIAPI=__attribute__((ms_abi))"
> > > > -maccumulate-outgoing-args -mno-red-zone -Wno-address -mcmodel=small
> > -fpie
> > > > -fno-asynchronous-unwind-tables -Wno-address
> > > > >  DEFINE GCC48_IA32_X64_ASLDLINK_FLAGS =
> > DEF(GCC48_IA32_X64_DLINK_COMMON)
> > > > -Wl,--entry,ReferenceAcpiTable -u ReferenceAcpiTable
> > > > >  DEFINE GCC48_IA32_X64_DLINK_FLAGS    =
> > DEF(GCC48_IA32_X64_DLINK_COMMON)
> > > > -Wl,--entry,$(IMAGE_ENTRY_POINT) -u $(IMAGE_ENTRY_POINT)
> > > > -Wl,-Map,$(DEST_DIR_DEBUG)/$(BASE_NAME).map,--whole-archive
> > > > >  DEFINE GCC48_IA32_DLINK2_FLAGS       =
> > > > -Wl,--defsym=PECOFF_HEADER_SIZE=0x220 DEF(GCC_DLINK2_FLAGS_COMMON)
> > > > > @@ -2613,15 +2613,15 @@ NOOPT_CLANG38_IA32_DLINK2_FLAGS     =
> > > > DEF(GCC5_IA32_DLINK2_FLAGS) -O0
> > > > >  *_CLANG38_X64_ASLPP_FLAGS          = DEF(GCC_ASLPP_FLAGS)
> > > > DEF(CLANG38_X64_TARGET)
> > > > >  *_CLANG38_X64_VFRPP_FLAGS          = DEF(GCC_VFRPP_FLAGS)
> > > > DEF(CLANG38_X64_TARGET)
> > > > >
> > > > > -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
> > > > > +DEBUG_CLANG38_X64_CC_FLAGS         = DEF(CLANG38_ALL_CC_FLAGS) -m64
> > > > -march=x86-64 "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone
> > > > -mcmodel=small -fpie -Oz -flto DEF(CLANG38_X64_TARGET) -g
> > > > >  DEBUG_CLANG38_X64_DLINK_FLAGS      = DEF(GCC5_IA32_X64_DLINK_FLAGS)
> > > > -flto -Wl,-Oz -Wl,-melf_x86_64 -Wl,--oformat=elf64-x86-64 -Wl,-pie
> > > > -mcmodel=small
> > > > >  DEBUG_CLANG38_X64_DLINK2_FLAGS     = DEF(GCC5_X64_DLINK2_FLAGS) -O3
> > > > >
> > > > > -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)
> > > > > +RELEASE_CLANG38_X64_CC_FLAGS       = DEF(CLANG38_ALL_CC_FLAGS) -m64
> > > > -march=x86-64 "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone
> > > > -mcmodel=small -fpie -Oz -flto DEF(CLANG38_X64_TARGET)
> > > > >  RELEASE_CLANG38_X64_DLINK_FLAGS    = DEF(GCC5_IA32_X64_DLINK_FLAGS)
> > > > -flto -Wl,-Oz -Wl,-melf_x86_64 -Wl,--oformat=elf64-x86-64 -Wl,-pie
> > > > -mcmodel=small
> > > > >  RELEASE_CLANG38_X64_DLINK2_FLAGS   = DEF(GCC5_X64_DLINK2_FLAGS) -O3
> > > > >
> > > > > -NOOPT_CLANG38_X64_CC_FLAGS         = DEF(CLANG38_ALL_CC_FLAGS) -m64
> > > > "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone -mcmodel=small -fpie
> > -O0
> > > > DEF(CLANG38_X64_TARGET) -g
> > > > > +NOOPT_CLANG38_X64_CC_FLAGS         = DEF(CLANG38_ALL_CC_FLAGS) -m64
> > > > -march=x86-64 "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone
> > > > -mcmodel=small -fpie -O0 DEF(CLANG38_X64_TARGET) -g
> > > > >  NOOPT_CLANG38_X64_DLINK_FLAGS      = DEF(GCC5_IA32_X64_DLINK_FLAGS)
> > > > -Wl,-O0 -Wl,-melf_x86_64 -Wl,--oformat=elf64-x86-64 -Wl,-pie
> > -mcmodel=small
> > > > >  NOOPT_CLANG38_X64_DLINK2_FLAGS     = DEF(GCC5_X64_DLINK2_FLAGS) -O0
> > > > >
> > > > > @@ -2798,17 +2798,17 @@ NOOPT_CLANGPDB_IA32_DLINK2_FLAGS     =
> > > > >  *_CLANGPDB_X64_ASLPP_FLAGS          = DEF(GCC_ASLPP_FLAGS)
> > > > DEF(CLANGPDB_X64_TARGET)
> > > > >  *_CLANGPDB_X64_VFRPP_FLAGS          = DEF(GCC_VFRPP_FLAGS)
> > > > DEF(CLANGPDB_X64_TARGET)
> > > > >
> > > > > -DEBUG_CLANGPDB_X64_CC_FLAGS         = DEF(CLANGPDB_ALL_CC_FLAGS)
> > -m64
> > > > "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone -mcmodel=small -Oz
> > -flto
> > > > DEF(CLANGPDB_X64_TARGET) -gcodeview  -funwind-tables
> > > > > +DEBUG_CLANGPDB_X64_CC_FLAGS         = DEF(CLANGPDB_ALL_CC_FLAGS)
> > -m64
> > > > -march=x86-64 "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone
> > > > -mcmodel=small -Oz -flto DEF(CLANGPDB_X64_TARGET) -gcodeview
> > > > -funwind-tables
> > > > >  DEBUG_CLANGPDB_X64_DLINK_FLAGS      = /NOLOGO /NODEFAULTLIB
> > > > /IGNORE:4001 /OPT:REF /OPT:ICF=10 /ALIGN:32 /FILEALIGN:32 /Machine:X64
> > /DLL
> > > > /ENTRY:$(IMAGE_ENTRY_POINT) /SUBSYSTEM:EFI_BOOT_SERVICE_DRIVER
> > /SAFESEH:NO
> > > > /BASE:0 /DEBUG:GHASH /MLLVM:-exception-model=wineh /lldmap
> > > > >  DEBUG_CLANGPDB_X64_DLINK2_FLAGS     =
> > > > >  DEBUG_CLANGPDB_X64_GENFW_FLAGS      = --keepexceptiontable
> > > > >
> > > > > -RELEASE_CLANGPDB_X64_CC_FLAGS       = DEF(CLANGPDB_ALL_CC_FLAGS)
> > -m64
> > > > "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone -mcmodel=small -Oz
> > -flto
> > > > DEF(CLANGPDB_X64_TARGET) -fno-unwind-tables
> > > > > +RELEASE_CLANGPDB_X64_CC_FLAGS       = DEF(CLANGPDB_ALL_CC_FLAGS)
> > -m64
> > > > -march=x86-64 "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone
> > > > -mcmodel=small -Oz -flto DEF(CLANGPDB_X64_TARGET) -fno-unwind-tables
> > > > >  RELEASE_CLANGPDB_X64_DLINK_FLAGS    = /NOLOGO /NODEFAULTLIB
> > > > /IGNORE:4001 /IGNORE:4254 /OPT:REF /OPT:ICF=10 /ALIGN:32 /FILEALIGN:32
> > > > /SECTION:.xdata,D /SECTION:.pdata,D /Machine:X64 /DLL
> > > > /ENTRY:$(IMAGE_ENTRY_POINT) /SUBSYSTEM:EFI_BOOT_SERVICE_DRIVER
> > /SAFESEH:NO
> > > > /BASE:0 /MERGE:.rdata=.data /MLLVM:-exception-model=wineh /lldmap
> > > > >  RELEASE_CLANGPDB_X64_DLINK2_FLAGS   =
> > > > >  RELEASE_CLANGPDB_X64_GENFW_FLAGS    =
> > > > >
> > > > > -NOOPT_CLANGPDB_X64_CC_FLAGS         = DEF(CLANGPDB_ALL_CC_FLAGS)
> > -m64
> > > > "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone -mcmodel=small -O0
> > > > DEF(CLANGPDB_X64_TARGET) -gcodeview -funwind-tables
> > > > > +NOOPT_CLANGPDB_X64_CC_FLAGS         = DEF(CLANGPDB_ALL_CC_FLAGS)
> > -m64
> > > > -march=x86-64 "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone
> > > > -mcmodel=small -O0 DEF(CLANGPDB_X64_TARGET) -gcodeview -funwind-tables
> > > > >  NOOPT_CLANGPDB_X64_DLINK_FLAGS      = /NOLOGO /NODEFAULTLIB
> > > > /IGNORE:4001 /OPT:REF /OPT:ICF=10 /ALIGN:32 /FILEALIGN:32 /Machine:X64
> > /DLL
> > > > /ENTRY:$(IMAGE_ENTRY_POINT) /SUBSYSTEM:EFI_BOOT_SERVICE_DRIVER
> > /SAFESEH:NO
> > > > /BASE:0 /DEBUG:GHASH /MLLVM:-exception-model=wineh /lldmap
> > > > >  NOOPT_CLANGPDB_X64_DLINK2_FLAGS     =
> > > > >  NOOPT_CLANGPDB_X64_GENFW_FLAGS      = --keepexceptiontable
> > > > > @@ -2901,15 +2901,15 @@ NOOPT_CLANGDWARF_IA32_DLINK2_FLAGS     =
> > > > DEF(CLANGDWARF_IA32_DLINK2_FLAGS) -O0 -
> > > > >  *_CLANGDWARF_X64_ASLPP_FLAGS          = DEF(GCC_ASLPP_FLAGS)
> > > > DEF(CLANG38_X64_TARGET)
> > > > >  *_CLANGDWARF_X64_VFRPP_FLAGS          = DEF(GCC_VFRPP_FLAGS)
> > > > DEF(CLANG38_X64_TARGET)
> > > > >
> > > > > -DEBUG_CLANGDWARF_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
> > > > > +DEBUG_CLANGDWARF_X64_CC_FLAGS         = DEF(CLANG38_ALL_CC_FLAGS)
> > -m64
> > > > -march=x86-64 "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone
> > > > -mcmodel=small -fpie -Oz -flto DEF(CLANG38_X64_TARGET) -g
> > > > >  DEBUG_CLANGDWARF_X64_DLINK_FLAGS      =
> > > > DEF(CLANGDWARF_IA32_X64_DLINK_FLAGS) -flto -Wl,-O3 -Wl,-melf_x86_64
> > > > -Wl,--oformat,elf64-x86-64 -Wl,-pie -mcmodel=small
> > > > -Wl,--apply-dynamic-relocs
> > > > >  DEBUG_CLANGDWARF_X64_DLINK2_FLAGS     =
> > > > DEF(CLANGDWARF_X64_DLINK2_FLAGS) -O3 -fuse-ld=lld
> > > > >
> > > > > -RELEASE_CLANGDWARF_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)
> > > > > +RELEASE_CLANGDWARF_X64_CC_FLAGS       = DEF(CLANG38_ALL_CC_FLAGS)
> > -m64
> > > > -march=x86-64 "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone
> > > > -mcmodel=small -fpie -Oz -flto DEF(CLANG38_X64_TARGET)
> > > > >  RELEASE_CLANGDWARF_X64_DLINK_FLAGS    =
> > > > DEF(CLANGDWARF_IA32_X64_DLINK_FLAGS) -flto -Wl,-O3 -Wl,-melf_x86_64
> > > > -Wl,--oformat,elf64-x86-64 -Wl,-pie -mcmodel=small
> > > > -Wl,--apply-dynamic-relocs
> > > > >  RELEASE_CLANGDWARF_X64_DLINK2_FLAGS   =
> > > > DEF(CLANGDWARF_X64_DLINK2_FLAGS) -O3 -fuse-ld=lld
> > > > >
> > > > > -NOOPT_CLANGDWARF_X64_CC_FLAGS         = DEF(CLANG38_ALL_CC_FLAGS)
> > -m64
> > > > "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone -mcmodel=small -fpie
> > -O0
> > > > DEF(CLANG38_X64_TARGET) -g
> > > > > +NOOPT_CLANGDWARF_X64_CC_FLAGS         = DEF(CLANG38_ALL_CC_FLAGS)
> > -m64
> > > > -march=x86-64 "-DEFIAPI=__attribute__((ms_abi))" -mno-red-zone
> > > > -mcmodel=small -fpie -O0 DEF(CLANG38_X64_TARGET) -g
> > > > >  NOOPT_CLANGDWARF_X64_DLINK_FLAGS      =
> > > > DEF(CLANGDWARF_IA32_X64_DLINK_FLAGS) -Wl,-O0 -Wl,-melf_x86_64
> > > > -Wl,--oformat,elf64-x86-64 -Wl,-pie -mcmodel=small
> > > > -Wl,--apply-dynamic-relocs
> > > > >  NOOPT_CLANGDWARF_X64_DLINK2_FLAGS     =
> > > > DEF(CLANGDWARF_X64_DLINK2_FLAGS) -O0 -fuse-ld=lld
> > > > >
> > > >
> > > >
> > > > 
> > > >
> > > >
> > > >
> > >
> >
> 
>