13 Commits

Author SHA1 Message Date
Fangrui Song
3e7eab0997 [RISCV] RISCVELFTargetObjectFile: use 2-byte alignment for .text if RVC
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
2023-05-11 13:44:37 -07:00
Craig Topper
29463612d2 [RISCV] Replace RISCV -> RISC-V in comments. NFC
To be consistent with RISC-V branding guidelines
https://riscv.org/about/risc-v-branding-guidelines/
Think we should be using RISC-V where possible.

More patches will follow.

Reviewed By: asb

Differential Revision: https://reviews.llvm.org/D146449
2023-03-27 09:50:17 -07:00
Leonard Chan
cdb9a0c086 [MC][CodeGen] Define R_RISCV_PLT32 and lower dso_local_equivalent to it
This introduces R_RISCV_PLT32, PC-relative data relocation that takes
the 32-bit relative offset to a function or its PLT entry from its
relocation location.

This is needed to support relative vtables on RISCV.

Github PR: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/363

The lld handling of this reloc is D143115.

Differential Revision: https://reviews.llvm.org/D143226
2023-02-23 01:26:27 +00:00
Fangrui Song
47c5576d7d ELF: Create unique SHF_GNU_RETAIN sections for llvm.used global objects
If a global object is listed in `@llvm.used`, place it in a unique section with
the `SHF_GNU_RETAIN` flag. The section is a GC root under `ld --gc-sections`
with LLD>=13 or GNU ld>=2.36.

For front ends which do not expect to see multiple sections of the same name,
consider emitting `@llvm.compiler.used` instead of `@llvm.used`.

SHF_GNU_RETAIN is restricted to ELFOSABI_GNU and ELFOSABI_FREEBSD in
binutils. We don't do the restriction - see the rationale in D95749.

The integrated assembler has supported SHF_GNU_RETAIN since D95730.
GNU as>=2.36 supports section flag 'R'.
We don't need to worry about GNU ld support because older GNU ld just ignores
the unknown SHF_GNU_RETAIN.

With this change, `__attribute__((retain))` functions/variables emitted
by clang will get the SHF_GNU_RETAIN flag.

Differential Revision: https://reviews.llvm.org/D97448
2021-02-26 16:38:44 -08:00
Craig Topper
f96a7706d9 [Target] Use Align in TargetLoweringObjectFile::getSectionForConstant.
Differential Revision: https://reviews.llvm.org/D80363
2020-05-21 15:23:29 -07:00
Fangrui Song
85c30f3374 [X86] Reland D71360 Clean up UseInitArray initialization for X86ELFTargetObjectFile
-fuse-init-array is now the CC1 default but TargetLoweringObjectFileELF::UseInitArray still defaults to false.
The following two unknown OS target triples continue using .ctors/.dtors because InitializeELF is not called.

clang -target i386 -c a.c
clang -target x86_64 -c a.c

This cleanup fixes this as a bonus.

X86SpeculativeLoadHardeningPass::tracePredStateThroughCall can call
MCContext::createTempSymbol before TargetLoweringObjectFileELF::Initialize().
We need to call TargetLoweringObjectFileELF::Initialize() ealier.

test/CodeGen/X86/speculative-load-hardening-indirect.ll

Differential Revision: https://reviews.llvm.org/D71360
2020-03-20 21:57:34 -07:00
Eric Christopher
fc7233d774 Temporarily Revert "[X86] Reland D71360 Clean up UseInitArray initialization for X86ELFTargetObjectFile"
as it's causing msan failures.

This reverts commit 7899fe9da8d8df6f19ddcbbb877ea124d711c54b.
2020-03-20 17:36:12 -07:00
Fangrui Song
7899fe9da8 [X86] Reland D71360 Clean up UseInitArray initialization for X86ELFTargetObjectFile
UseInitArray is now the CC1 default but TargetLoweringObjectFileELF::UseInitArray still defaults to false.
The following two unknown OS target triples continue using .ctors/.dtors because InitializeELF is not called.

clang -target i386 -c a.c
clang -target x86_64 -c a.c

This cleanup fixes this as a bonus.

Differential Revision: https://reviews.llvm.org/D71360
2020-03-20 11:18:36 -07:00
Mitch Phillips
2423774cc2 Revert "Honor -fuse-init-array when os is not specified on x86"
This reverts commit aa5ee8f244441a8ea103a7e0ed8b6f3e74454516.

This change broke the sanitizer buildbots. See comments at the patchset
(https://reviews.llvm.org/D71360) for more information.
2019-12-17 07:36:59 -08:00
Kamlesh Kumar
aa5ee8f244 Honor -fuse-init-array when os is not specified on x86
Currently -fuse-init-array option is not effective when target triple
does not specify os, on x86,x86_64.
i.e.

// -fuse-init-array is not honored.
$ clang -target i386 -fuse-init-array test.c -S

// -fuse-init-array is honored.
$ clang -target i386-linux -fuse-init-array test.c -S

This patch fixes first case.
And does cleanup.

Reviewers: rnk, craig.topper, fhahn, echristo

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D71360
2019-12-16 15:21:23 -08:00
Shiva Chen
7cc03bd064 [RISCV] Put data smaller than eight bytes to small data section
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
2019-04-11 04:59:13 +00:00
Chandler Carruth
2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
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
2019-01-19 08:50:56 +00:00
Mandeep Singh Grang
98bc25a0f2 [RISCV] Use init_array instead of ctors for RISCV target, by default
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
2018-03-24 18:37:19 +00:00