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


Shi, Steven <steven.shi@...>
 

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

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