Re: [PATCH v5 0/8] BaseTools: add support for GCC5 in LTO mode

["Shi, Steven" <steven.shi@intel.com>]

Ard,
Thank you to check in GCC5! 


Steven Shi
Intel\SSG\STO\UEFI Firmware

Tel: +86 021-61166522
iNet: 821-6522


> -----Original Message-----
> From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org]
> Sent: Tuesday, August 02, 2016 5:03 PM
> To: Shi, Steven <steven.shi@intel.com>; Zhu, Yonghong
> <yonghong.zhu@intel.com>; Gao, Liming <liming.gao@intel.com>; Justen,
> Jordan L <jordan.l.justen@intel.com>; edk2-devel-01 <edk2-
> devel@lists.01.org>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>; Laszlo Ersek
> <lersek@redhat.com>; Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Subject: Re: [PATCH v5 0/8] BaseTools: add support for GCC5 in LTO mode
> 
> On 1 August 2016 at 10:01, Ard Biesheuvel <ard.biesheuvel@linaro.org>
> wrote:
> > This v5 to introduce GCC5 is now a 8 piece series, including some
> > preparatory cleanup patches that allow all GCC4x and CLANG35 toolchains
> > to switch to using 'gcc' as the linker. This allows us to get rid of
> > the wrapper script to marshall ld arguments in order to make them
> > understandable by gcc, which is fragile and likely to cause problems in
> > the future.
> >
> > Since there appears to be a natural split between the 'legacy' GCC
> > toolchains UNIXGCC, ELFGCC, and CYGGCC[xASL], both in term of
> supported
> > architectures [IA32, X64, IPF] vs [IA32, X64, ARM, AARCH64], and in
> > terms of maintenance, these toolchains are not moved to using 'gcc' as
> > the linker, and instead, a new BUILDRULEFAMILY is introduced called
> GCCLD
> > that will retain the old behavior.
> >
> > The result is that GCC5 can align much more closely with its predecessors,
> > making the expected maintenance burden of supporting GCC back to v4.4
> > much lower.
> >
> > Changes since v4:
> > - added patch to use 'protected' visibility only for the libraries that
> >   define the module entry points (_ModuleEntryPoint), to prevent them
> from
> >   being optimized away by the LTO routines
> > - added Jordan's ack/RBs
> > - add some extra comments to tools_def.template (#8)
> >
> 
> Thanks all. Committed as
> 
> 1c63516075b3 BaseTools CLANG35: drop problematic use-movt and save-
> temps options
> ff54bcdf2e4e ArmVirtPkg/ArmVirtPrePiUniCoreRelocatable: ignore .hash
> and .note sections
> befb3ba51502 BaseTools UNIXGCC ELFGCC CYGGCC: clone GCC build rule
> family into GCCLD
> a1b8baccc30b BaseTools GCC: use 'gcc' as the linker command for GCC44
> and later
> e1458aaded8e ArmPkg: add prebuilt glue binaries for GCC5 LTO support
> 7fd5d619806d BaseTools GCC: drop GNU notes section from EFI image
> 4a8466d4baba BaseTools GCC: introduce GCC5 toolchain to support GCC
> v5.x in LTO mode
> 
> with Leif and Liming's R-b. I dropped patch #7, and instead made the
> visibility pragma conditional on whether LTO is disabled.
> 
> --
> Ard.
> 
> 
> > Changes since v3:
> > - like Steven does in his GCC5LTO patch, add -fno-builtin to IA32 and X64
> >   CC_FLAGS; this addresses a build issue reported by Liming
> > - add -Os the the linker flags as well, for AARCH64 this does not seem to
> make
> >   a difference, but it is arguably correct since the LTO processing at link
> >   time involves code generation as well
> > - add Laszlo's ack to #2
> > - new patch #6 to omit the autogenerated build-id from the PE/COFF binary
> >
> > Changes since v2:
> > - add license headers to LTO glue files for ARM and AARCH64 (#5)
> > - get rid of lto-ld-wrapper script
> >
> > Ard Biesheuvel (8):
> >   BaseTools CLANG35: drop problematic use-movt and save-temps options
> >   ArmVirtPkg/ArmVirtPrePiUniCoreRelocatable: ignore .hash and .note
> >     sections
> >   BaseTools UNIXGCC ELFGCC CYGGCC: clone GCC build rule family into
> >     GCCLD
> >   BaseTools GCC: use 'gcc' as the linker command for GCC44 and later
> >   ArmPkg: add prebuilt glue binaries for GCC5 LTO support
> >   BaseTools GCC: drop GNU notes section from EFI image
> >   MdePkg GCC/X64: avoid 'hidden' visibility for module entry points
> >   BaseTools GCC: introduce GCC5 toolchain to support GCC v5.x in LTO
> >     mode
> >
> >  ArmPkg/GccLto/liblto-aarch64.a                                         | Bin 0 -> 1016
> bytes
> >  ArmPkg/GccLto/liblto-aarch64.s                                         |  27 ++
> >  ArmPkg/GccLto/liblto-arm.a                                             | Bin 0 -> 2096 bytes
> >  ArmPkg/GccLto/liblto-arm.s                                             |  61 ++++
> >  ArmVirtPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf                    |   2 +-
> >  ArmVirtPkg/PrePi/Scripts/PrePi-PIE.lds                                 |   3 +
> >  BaseTools/Conf/build_rule.template                                     |  31 +-
> >  BaseTools/Conf/tools_def.template                                      | 350
> +++++++++++++++-----
> >  BaseTools/Scripts/GccBase.lds                                          |   6 +
> >  EmulatorPkg/Unix/Host/Host.inf                                         |   6 +-
> >  MdePkg/Include/X64/ProcessorBind.h                                     |   9 +-
> >  MdePkg/Library/DxeCoreEntryPoint/DxeCoreEntryPoint.inf                 |   2 +
> >  MdePkg/Library/PeiCoreEntryPoint/PeiCoreEntryPoint.inf                 |   2 +
> >  MdePkg/Library/PeimEntryPoint/PeimEntryPoint.inf                       |   2 +
> >  MdePkg/Library/UefiApplicationEntryPoint/UefiApplicationEntryPoint.inf |
> 2 +
> >  MdePkg/Library/UefiDriverEntryPoint/UefiDriverEntryPoint.inf           |   2 +
> >  16 files changed, 396 insertions(+), 109 deletions(-)
> >  create mode 100644 ArmPkg/GccLto/liblto-aarch64.a
> >  create mode 100644 ArmPkg/GccLto/liblto-aarch64.s
> >  create mode 100644 ArmPkg/GccLto/liblto-arm.a
> >  create mode 100644 ArmPkg/GccLto/liblto-arm.s
> >
> > --
> > 2.7.4
> >