D57497 added -msmall-data-limit= as an alias for -G and defaulted it to 8 for
-fno-pic/-fpie.
The behavior is already different from GCC in a few ways:
* GCC doesn't accept -G.
* GCC -fpie doesn't seem to use -msmall-data-limit=.
* GCC emits .srodata.cst* that we don't use (#82214). Writable contents
caused confusion (https://bugs.chromium.org/p/llvm/issues/detail?id=61)
In addition,
* claiming `-shared` means we don't get a desired `-Wunused-command-line-argument` for `clang --target=riscv64-linux-gnu -fpic -c -shared a.c`.
* -mcmodel=large doesn't work for RISC-V yet, so the special case is strange.
* It's quite unusual to emit a warning when an option (unrelated to relocation model) is used with -fpic.
* We don't want future configurations (Android) to continue adding customization to `SetRISCVSmallDataLimit`.
I believe the extra code just doesn't pull its weight and should be
cleaned up. This patch also changes the default to 0. GP relaxation
users are encouraged to specify these customization options explicitly.
Pull Request: https://github.com/llvm/llvm-project/pull/83093
Small mergeable read only data was place on the sdata before, but it
also means it lose the mergeable property, which means lose some code
size optimization opportunity during link time.
…v64 ELF
This is similar to https://github.com/llvm/llvm-project/pull/67754 but
adds support for ELF aarch64 and riscv64 now that GOTPCREL-equivalent
relocations have been added for those archs.
For the "C" Standard Extension/Zca, D45560 enabled 2-byte alignment for
assembly output (e.g. `clang -S a.c`) and D102052 enabled 2-byte alignment for
assembly input and object file output (e.g. `clang -c a.s`).
This patch ports the behavior for code generation and object file output by
adding RISCVELFTargetObjectFile::getTextSectionAlignment (e.g. `clang -c a.c`).
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D150240
Because of gp = sdata_start_address + 0x800, gp with signed twelve-bit offset
could covert most of the small data section. Linker relaxation could transfer
the multiple data accessing instructions to a gp base with signed twelve-bit
offset instruction.
Differential Revision: https://reviews.llvm.org/D57493
llvm-svn: 358150
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Summary:
LLVM defaults to the newer .init_array/.fini_array scheme for static
constructors rather than the less desirable .ctors/.dtors (the UseCtors
flag defaults to false). This wasn't being respected in the RISC-V
backend because it fails to call TargetLoweringObjectFileELF::InitializeELF with the the appropriate
flag for UseInitArray.
This patch fixes this by implementing RISCVELFTargetObjectFile and overriding its Initialize method to call
InitializeELF(TM.Options.UseInitArray).
Reviewers: asb, apazos
Reviewed By: asb
Subscribers: mgorny, rbar, johnrusso, simoncook, jordy.potman.lists, sabuasal, niosHD, kito-cheng, shiva0217, llvm-commits
Differential Revision: https://reviews.llvm.org/D44750
llvm-svn: 328433
