871 Commits

Author SHA1 Message Date
Kazu Hirata
f347a06591
[lld] Use llvm::unique (NFC) (#136453) 2025-04-19 13:35:51 -07:00
Csanád Hajdú
10f75b8ef7
[LLD][ELF][AArch64] Mark .plt and .iplt with PURECODE flag (#134798)
Mark the synthetic sections `.plt` and `.iplt` with the
`SHF_AARCH64_PURECODE` section flag, allowing them to be placed in an
executable-only segment.
2025-04-17 16:26:11 +02:00
Peter Smith
e47d3a3088
[LLD][AArch64] Increase alignment of AArch64AbsLongThunk to 8 (#133738)
This permits an AArch64AbsLongThunk to be used in an environment where
unaligned accesses are disabled.

The AArch64AbsLongThunk does a load of an 8-byte address. When unaligned
accesses are disabled this address must be 8-byte aligned.

The vast majority of AArch64 systems will have unaligned accesses
enabled in userspace. However, after a reset, before the MMU has been
enabled, all memory accesses are to "device" memory, which requires
aligned accesses. In systems with multi-stage boot loaders a thunk may
be required to a later stage before the MMU has been enabled.

As we only want to increase the alignment when the ldr is used we delay
the increase in thunk alignment until we know we are going to write an
ldr. We also need to account for the ThunkSection alignment increase
when this happens.

In some of the test updates, particularly those with shared CHECK lines
with position independent thunks it was easier to ensure that the thunks
started at an 8-byte aligned address in all cases.
2025-04-01 09:49:27 +01:00
Fangrui Song
52fc6ffcda [ELF] Refine isExported/isPreemptible condition
Reland 994cea3f0a2d0caf4d66321ad5a06ab330144d89 after bolt tests no
longer rely on -pie --unresolved-symbols=ignore-all with no input DSO
generating PLT entries.

---

Commit f10441ad003236ef3b9e5415a571d2be0c0ce5ce , while dropping a
special case for isUndefWeak and --no-dynamic-linking, made
--export-dynamic ineffective when -pie is used without any input DSO.

This change restores --export-dynamic and unifies -pie and -pie
--no-dynamic-linker when there is no input DSO.

* -pie with no input DSO suppresses undefined symbols in .dynsym.
  Previously this only appied to -pie --no-dynamic-linker.
* As a side effect, -pie with no input DSO suppresses PLT.
2025-02-05 21:16:00 -08:00
Nikita Popov
b84f7d17f8 Revert "[ELF] Refine isExported/isPreemptible condition"
This reverts commit 994cea3f0a2d0caf4d66321ad5a06ab330144d89.

Try to fix the bolt test failures in pre-merge checks.
2025-02-03 10:01:53 +01:00
Fangrui Song
994cea3f0a [ELF] Refine isExported/isPreemptible condition
Commit f10441ad003236ef3b9e5415a571d2be0c0ce5ce dropped a special case
for isUndefWeak and --no-dynamic-linking but also made --export-dynamic
ineffective for static PIE.

This change restores the --export-dynamic behavior and entirely drops
special handling of --no-dynamic-linker:

* -pie with no input DSO, similar to --no-dynamic-linker, suppresses
  undefined symbols in .dynsym

The new behaviors resemble GNU ld more.
2025-01-31 20:37:18 -08:00
Fangrui Song
d6fa74ab3d [ELF] Merge exportDynamic/isExported and remove Symbol::includeInDynsym
Commit 3733ed6f1c6b0eef1e13e175ac81ad309fc0b080 introduced isExported to
cache includeInDynsym. If we don't unnecessarily set isExported for
undefined symbols, exportDynamic/includeInDynsym can be replaced with
isExported.
2025-01-30 22:24:04 -08:00
Daniil Kovalev
9178708c3b
[PAC][lld][AArch64][ELF] Support signed TLSDESC (#113817)
Depends on #120010

Support `R_AARCH64_AUTH_TLSDESC_ADR_PAGE21`, `R_AARCH64_AUTH_TLSDESC_LD64_LO12`
and `R_AARCH64_AUTH_TLSDESC_LD64_LO12` static relocations and
`R_AARCH64_AUTH_TLSDESC` dynamic relocation. IE/LE optimization is not
currently supported for AUTH TLSDESC.
2025-01-22 12:18:05 +03:00
Fangrui Song
510a5c7fc2 [ELF] Fix .gnu.version crash when .dynsym is discarded
Fix #88650

In addition, delete the unneeded comment.
https://sourceware.org/gnu-gabi/program-loading-and-dynamic-linking.txt
2025-01-02 18:46:44 -08:00
Daniil Kovalev
417d2d7ce6
[PAC][lld][AArch64][ELF] Support signed GOT (#113815)
Depends on #113811

Support `R_AARCH64_AUTH_ADR_GOT_PAGE`, `R_AARCH64_AUTH_GOT_LO12_NC` and
`R_AARCH64_AUTH_GOT_ADD_LO12_NC` GOT-generating relocations. For preemptible
symbols, dynamic relocation `R_AARCH64_AUTH_GLOB_DAT` is emitted. Otherwise,
we unconditionally emit `R_AARCH64_AUTH_RELATIVE` dynamic relocation since
pointers in signed GOT needs to be signed during dynamic link time.
2024-12-17 10:23:01 +03:00
Peter Collingbourne
64da33a589
ELF: Introduce --randomize-section-padding option.
The --randomize-section-padding option randomly inserts padding between
input sections using the given seed. It is intended to be used in A/B
experiments to determine the average effect of a change on program
performance, while controlling for effects such as false sharing in
the cache which may introduce measurement bias. For more details,
see the RFC:

https://discourse.llvm.org/t/rfc-lld-feature-for-controlling-for-code-size-dependent-measurement-bias/83334

Reviewers: smithp35, MaskRay

Reviewed By: MaskRay, smithp35

Pull Request: https://github.com/llvm/llvm-project/pull/117653
2024-12-13 11:52:09 -08:00
Fangrui Song
04996a28b7
[ELF] Rename target-specific RelExpr enumerators
RelExpr enumerators are named `R_*`, which can be confused with ELF
relocation type names. Rename the target-specific ones to `RE_*` to
avoid confusion.

For consistency, the target-independent ones can be renamed as well, but
that's not urgent. The relocation processing mechanism with RelExpr has
non-trivial overhead compared with mold's approach, and we might make
more code into Arch/*.cpp files and decrease the enumerators.

Pull Request: https://github.com/llvm/llvm-project/pull/118424
2024-12-03 09:17:17 -08:00
Fangrui Song
1cd627562b [ELF] Remove unneeded Twine in ELFSyncStream 2024-11-24 12:13:02 -08:00
Fangrui Song
c4dc5ed825 [ELF] Avoid some toStr and ErrAlways 2024-11-24 11:43:40 -08:00
Fangrui Song
a5af6214dd [ELF] Make SyntheticSection parameter order match InputSection
And rename `/*alignment=*/` to `/*addralign=*/`
2024-11-23 15:16:36 -08:00
Fangrui Song
43e3871a32 [ELF] Make section member orders consistent
SectionBase, InputSectionBase, InputSection, MergeInputSection, and
OutputSection have different member orders. Make them consistent and
adopt the order similar to the raw Elf64_Shdr.
2024-11-23 14:22:24 -08:00
Fangrui Song
a52032448e [ELF] Avoid make<PhdrEntry>
Store them in Partition::phdrs instead.
2024-11-19 22:38:14 -08:00
Fangrui Song
5b1b6a62b8 [ELF] Make elfHeader/programHeaders unique_ptr
This removes some SpecificAlloc instantiations, makes lld smaller, and
drops the small memory waste due to the separate BumpPtrAllocator.
2024-11-17 00:25:42 -08:00
Fangrui Song
53dc4e7600 [ELF] createSyntheticSections: replace some make<> with unique_ptr
This removes some SpecificAlloc instantiations and makes lld smaller.
This drops the small memory waste due to the separate BumpPtrAllocator.
2024-11-17 00:09:06 -08:00
Fangrui Song
2991a4e209 [ELF] Replace functions bAlloc/saver/uniqueSaver with member access 2024-11-16 22:34:13 -08:00
Fangrui Song
483516fd83 [ELF] Remove unneeded Twine() 2024-11-16 20:32:44 -08:00
Fangrui Song
73bb022b46 [ELF] Remove global ctx
This commit completes the work that eliminates global variables like
config/target/inputSections/symTab from lld/ELF.

Key changes:

* Introduced `lld:🧝:ctx` to encapsulate global state.
* Moved global variables into `Ctx lld:🧝:ctx`
* Updated many functions to accept `Ctx &ctx`
* Made `ctx` a local variable (this commit)

If we don't count `static std::mutex`, this is the last major global
state within lld/ELF (minor ones like `SharedFile::vernauxNum`
(33ff9e43b4c5bdc3da31c6b11ad51d35a69bec5f) might not all be eliminated
yet).
2024-11-16 17:24:11 -08:00
Fangrui Song
33ff9e43b4 [ELF] Move SharedFile::vernauxNum to Ctx 2024-11-16 17:00:51 -08:00
Fangrui Song
7d13775486 [ELF] Pass ctx & 2024-11-16 15:48:01 -08:00
Fangrui Song
a626eb2a2f [ELF] Pass ctx to bAlloc/saver/uniqueSaver 2024-11-16 15:20:21 -08:00
Fangrui Song
58a971f42f [ELF] Replace contex-less toString(x) with toStr(ctx, x)
so that we can remove the global `ctx` from toString implementations.
Rename lld::toString (to lld:🧝:toStr) to simplify name lookup (we
have many llvm::toString and another lld::toString(const llvm::opt::Arg
&)).
2024-11-16 11:58:10 -08:00
Fangrui Song
d69cc05bcf [ELF] Migrate away from global ctx 2024-11-14 22:30:29 -08:00
Fangrui Song
e24457a330 [ELF] Migrate away from global ctx 2024-11-14 22:17:10 -08:00
Fangrui Song
c13258ac49 [ELF] Replace log with Log(ctx) 2024-11-07 09:30:20 -08:00
Fangrui Song
9b058bb42d [ELF] Replace errorOrWarn(...) with Err 2024-11-06 22:33:51 -08:00
Fangrui Song
f8bae3af74 [ELF] Replace warn(...) with Warn 2024-11-06 22:19:31 -08:00
Fangrui Song
09c2c5e1e9 [ELF] Replace error(...) with ErrAlways or Err
Most are migrated to ErrAlways mechanically.
In the future we should change most to Err.
2024-11-06 22:04:52 -08:00
Fangrui Song
63c6fe4a0b [ELF] Replace fatal(...) with Fatal or Err 2024-11-06 21:17:26 -08:00
Fangrui Song
861bd36bce [ELF] Pass Ctx & to Symbol::getVA 2024-10-19 20:32:58 -07:00
Fangrui Song
fe8af49a1b [ELF] Pass Ctx & to Defined & CommonSymbol 2024-10-20 01:38:16 +00:00
Fangrui Song
682925ef43 [ELF] Pass Ctx & to Partition 2024-10-15 22:58:07 -07:00
Fangrui Song
0dbc85a59f [ELF] Pass Ctx & to Arch-specific code 2024-10-13 11:08:06 -07:00
Fangrui Song
002ca63b3f [ELF] Pass Ctx & to (read|write)(16|64) 2024-10-13 10:47:18 -07:00
Fangrui Song
38dfcd9ac9 [ELF] Pass Ctx & to read32/write32 2024-10-13 10:37:47 -07:00
Fangrui Song
a3bad9adcb [ELF] Pass Ctx & 2024-10-12 09:56:05 -07:00
Fangrui Song
dbd197118d [ELF] Pass Ctx & to Symbol 2024-10-11 23:34:43 -07:00
Fangrui Song
dd326b1225 [ELF] Pass Ctx & 2024-10-11 21:10:05 -07:00
Fangrui Song
d0606c265e [ELF] Make .comment have a non-full file
This ensures that SectionBase::file is non-null except
InputSection::discarded.
2024-10-11 20:55:21 -07:00
Fangrui Song
9bf2e20b17 [ELF] Pass Ctx & to OutputSection 2024-10-11 20:28:58 -07:00
Fangrui Song
6dd773b650 [ELF] Pass Ctx & 2024-10-11 20:15:02 -07:00
Fangrui Song
1c28f31133 [ELF] Pass Ctx & 2024-10-11 18:35:02 -07:00
Fangrui Song
81bd712f92 [ELF] Revert Ctx & parameters from SyntheticSection
Since Ctx &ctx is a member variable,
1f391a75af8685e6bba89421443d72ac6a186599
7a5b9ef54eb96abd8415fd893576c42e51fd95db
e2f0ec3a3a8a2981be8a1aac2004cfb9064c61e8 can be reverted.
2024-10-10 23:43:21 -07:00
Fangrui Song
d91c103a10 [ELF] Pass Ctx & to SyntheticSections 2024-10-10 23:28:25 -07:00
Fangrui Song
25cda9e069 [ELF] Pass Ctx & to SyntheticSection 2024-10-10 23:07:02 -07:00
Fangrui Song
cfd3289a1f [ELF] Pass Ctx & to some free functions 2024-10-06 19:36:21 -07:00