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

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

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
>