Symbols with regular GOT entries do need to be exported, but those that
are internalized (and have dymmy/internal GOT entries) need not be
exported.
This happens to fix the failures on the emscripten waterfall where extra
symbols were being exported by the linker (and then later removed by
wasm-opt).
Differential Revision: https://reviews.llvm.org/D119902
Reported by Stefan Pintilie in D119773.
For a branch to a hidden undefined weak symbol, there is an
`assert(sym->getVA());` failure in PPC64LongBranchTargetSection::writeTo for a
-no-pie link. The root cause is that we unnecessarily create the thunk for the
-no-pie link.
Fix this by changing the condition to just `s.isUndefined()`. See the inline
comment.
Rename ppc64-weak-undef-call.s to ppc64-undefined-weak.s to be consistent with
other architectures.
Reviewed By: sfertile, stefanp
Differential Revision: https://reviews.llvm.org/D119787
https://maskray.me/blog/2022-01-16-archives-and-start-lib
For every definition in an extracted archive member, we intern the symbol twice,
once for the archive index entry, once for the .o symbol table after extraction.
This is inefficient.
Symbols in a --start-lib ObjFile/BitcodeFile are only interned once because the
result is cached in symbols[i].
Just handle an archive using the --start-lib code path. We can therefore remove
ArchiveFile and LazyArchive. For many projects, archive member extraction ratio
is high and it is a net performance win. Linking a Release build of clang is
1.01x as fast.
Note: --start-lib scans symbols in the same order that llvm-ar adds them to the
index, so in the common case the semantics should be identical. If the archive
symbol table was created in a different order, or is incomplete, this strategy
may have different semantics. Such cases are considered user error.
The `is neither ET_REL nor LLVM bitcode` error is changed to a warning.
Previously an archive may have such members without a diagnostic. Using a
warning prevents breakage.
* For some tests, the diagnostics get improved where we did not consider
the archive member name: `b.a:` => `b.a(b.o):`.
* `no-obj.s`: the link is now allowed, matching GNU ld
* `archive-no-index.s`: the `is neither ET_REL nor LLVM bitcode` diagnostic is
demoted to a warning.
* `incompatible.s`: even when an archive is unextracted, we may report an
"incompatible with" error.
---
I recently decreased sizeof(SymbolUnion) by 8 and decreased memory usage quite a
bit, so retaining `symbols` for un-extracted archive members should not cause a
memory usage problem.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D119074
These global TLS symbols are shared across all shared libraries and
therefor should not be assumed to be local to the current module.
Also add new error in the linker when TLS relocations are used against
undefined symbols. TLS relocations are offsets into the current modules
tls data segment, and don't make sense for undefined symbols which are
modeled as global imports.
Fixes: https://github.com/emscripten-core/emscripten/issues/13398
Differential Revision: https://reviews.llvm.org/D119630
By unsetting this property, we are now able to internalize more symbols
during LTO. I compared the output of `-save-temps` for both LLD and
ld64, and we now match ld64's behavior as far as `lto-internalize.ll` is
concerned.
(Thanks @smeenai for working on an initial version of this diff!)
Fixes https://github.com/llvm/llvm-project/issues/50574.
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D119372
Makes lld-link work in a non-MSVC shell by autodetecting MSVC toolchain. Also
adds support for /winsysroot and a few other switches.
All this is done by refactoring to share code with clang-cl's existing support
for the same.
Differential Revision: https://reviews.llvm.org/D118070
... to use hyphens instead of underscores, making it consistent with
our other substitutions like %no-arg-lld and %lld-watchos.
Reviewed By: keith
Differential Revision: https://reviews.llvm.org/D119513
We have a mix of substituted lld (`%lld`) and hard-coded lld (`ld64.lld`) commands.
When testing with different versions of LLD, this would require going into every place
where lld is hard-coded and changing that. If we centralize it, this'll only require us
to modify it in only one place and will make it easy to run the same test suite. Plus,
this will make it be consistent with how we write other tests.
Reviewed By: #lld-macho, int3, oontvoo
Differential Revision: https://reviews.llvm.org/D119394
Having clarified that executing the SerializeToHsaco pass can
depend on a ROCm installation, switch from calling lld as a library to
using the copy of lld guaranteed to be included in a ROCm install.
This removes the workaround introduced in D119277
Reviewed By: whchung
Differential Revision: https://reviews.llvm.org/D119463
https://maskray.me/blog/2022-02-06-all-about-common-symbols#no-define-common
In GNU ld, -dc only affects -r links and causes COMMON symbols to be allocated.
--no-define-common is defined to make COMMON symbols undefined for -shared.
AIUI --no-define-common is a workaround around glibc 2.1 time and not really useful.
gold confuses --define-common with -d/FORCE_COMMON_ALLOCATION and implements
--define-common with -d semantics. Its --no-define-common is incompatible with
GNU ld.
In ld.lld, b2a23cf3c0 fixed the default -r
behavior for COMMON symbols but ported the incompatible gold
--[no-]define-common. To the best of my knowledge, no project uses -dp
--[no-]define-common. So just remove these options.
-d/-dc are used by the following projects:
* grub grub-core/genmod.sh.in uses -Wl,-r,-d (https://lists.gnu.org/archive/html/grub-devel/2022-02/msg00088.html)
* FreeBSD crunchgen uses -Wl,-dc (https://reviews.freebsd.org/D34215)
A no-op implementation works for them. Only when a program inspects relocatable
output by itself and does not recognize COMMON symbols, there may be a problem.
This is an extremely unlikely case.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D119108
This fixes the issue raised in https://reviews.llvm.org/D108850#3303452
Before C++17, the function object is evaluated in a unspecified order. In the following example: https://godbolt.org/z/8ao4vdsr7 the function object is either evaluated before or after the arguments, depending on the compiler. With MSVC and /std:c++14 the function object is evaluated after the arguments; with clang and gcc, it is evaluated before. With C++17, the function object is guaranteed to be evaluated before the arguments, see: https://riptutorial.com/cplusplus/example/19369/evaluation-order-of-function-arguments
In our case, the issue was that the `args` conversion to `ArrayRef` was evaluated before the lambda call `link`, which internally was calling `parseFlavor()`, which in turned modified `args`. We ended with an `ArrayRef` argument that reflected the previous contents of `args`.
Add coverage for `-flavor` which we didn't have before.
Differential Revision: https://reviews.llvm.org/D119278
This makes it easier to pinpoint the source of the problem.
TODO: Have more relocation error messages make use of this
functionality.
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D118798
to decrease sizeof(SymbolUnion) from 72 to 64 on ELF64 platforms.
Use a dummy `Undefined` to prevent null pointer dereference (though unused)
`*rel.sym` in InputSectionBase::relocateAlloc.
The relocation order may shuffle a bit, but otherwise there is no behavior
difference.
lld/ELF/OutputSections.cpp includes llvm/Config/config.h for
LLVM_ENABLE_ZLIB definition, but llvm/Config/config.h doesn't exist in
standalone build.
To fix this, this patch moves LLVM_ENABLE_ZLIB from config.h to
llvm-config.h and updates OutputSections.cpp to include llvm-config.h
instead of config.h
Reviewed By: MaskRay, mgorny
Differential Revision: https://reviews.llvm.org/D119058
Adds `-pagezero_size`. `-pagezero_size` commonly used for kernel development.
`-pagezero_size` changes the `__PAGEZERO` size, removing that segment if it is set to zero.
One of the four flags from {D118570}
Now with error messages and tests.
Differential Revision: https://reviews.llvm.org/D118724
SharedSymbol::SharedSymbol initializes verdefIndex and Symbol::replace
copies verdefIndex.
By move verdefIndex assignment outside of ctor, Symbol::replace can be changed
to not copy verdefIndex. This can be used to decrease work for for
ObjKind/BitcodeKind.
Currently `this->getName() == newSym.getName()`.
By keeping the old nameData/nameSize, newSym's nameData/nameSize will be
ignored. The call sites can avoid calling getName().
printTraceSymbol needs to take the symbol name since `other`'s name is empty.
* partition and isPreemptible are frequently used. Move it to the front
* move used beside isUsedInRegularObj. They are similar and accessed together in .symtab finalizing
* move auxIdx/dynsymIndex/verdefIndex to the end.
This decreases code size.
For -no-pie/-pie, when `__real_foo` is interposable in a shared object, `foo` is
exported. This rule does not match GNU ld and is unneeded because:
* the exported `foo` does not interpose `__real_foo` at run-time
* the similar `__wrap_foo` <-> `foo` relation does not have the rule
A STV_PROTECTED shared definition does not set exportDynamic of a defined
symbol. This is on the basis that a protected definition cannot be preempted so
the export is unnecessary. However, the condition is imperfect because we don't
know whether the shared object was built with a symbolic option. Since dropping
the condition simplifies code and matches GNU ld, let's do it.
There's a couple of motivations here:
* LLD 12 (which I was originally testing with) was adding an undefined
symbol to the symbol table if you attempted to wrap an unreferenced
lazy symbol, which would later break `--no-allow-shlib-undefined`. LLD
on main actually produces a weak undefined symbol, so this doesn't
break anyway, but it's cleaner to not have the weak undefined symbol
as well. The new behavior also matches bfd and gold.
* PROVIDE in a linker script referencing a wrapped symbol would think
that an otherwise-unreferenced lazy symbol which was wrapped was
actually referenced, and therefore proceed with the definition, which
goes against expectations. The new behavior also matches bfd and gold.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D118756
Xcode 13 comes with a mismatched platform in libcompiler_rt.dylib,
so this creates a linker error on mac catalyst.
Fix it by adding it to the skip list.
Reviewed By: MaskRay, #lld-macho, int3
Differential Revision: https://reviews.llvm.org/D117925
-fprofile-use=/-fprofile-sample-use= compiles may produce REL-format
.rel.llvm.call-graph-profile even if the prevailing format is RELA on AArch64.
Add R_AARCH64_NONE to getImplicitAddend to fix this linker error:
```
ld.lld: error: internal linker error: cannot read addend for relocation R_AARCH64_NONE
PLEASE submit a bug report to https://crbug.com and run tools/clang/scripts/process_crashreports.py (only works inside Google) which will upload a report and include the crash backtrace.
```
Earlier in LLD's evolution, I tried to create the illusion that
subsections were indistinguishable from "top-level" sections. Thus, even
though the subsections shared many common field values, I hid those
common values away in a private Shared struct (see D105305). More
recently, however, @gkm added a public `Section` struct in D113241 that
served as an explicit way to store values that are common to an entire
set of subsections (aka InputSections). Now that we have another "common
value" struct, `Shared` has been rendered redundant. All its fields can
be moved into `Section` instead, and the pointer to `Shared` can be replaced
with a pointer to `Section`.
This `Section` pointer also has the advantage of letting us inspect other
subsections easily, simplifying the implementation of {D118798}.
P.S. I do think that having both `Section` and `InputSection` makes for
a slightly confusing naming scheme. I considered renaming `InputSection`
to `Subsection`, but that would break the symmetry with `OutputSection`.
It would also make us deviate from LLD-ELF's naming scheme.
This change is perf-neutral on my 3.2 GHz 16-Core Intel Xeon W machine:
base diff difference (95% CI)
sys_time 1.258 ± 0.031 1.248 ± 0.023 [ -1.6% .. +0.1%]
user_time 3.659 ± 0.047 3.658 ± 0.041 [ -0.5% .. +0.4%]
wall_time 4.640 ± 0.085 4.625 ± 0.063 [ -1.0% .. +0.3%]
samples 49 61
There's also no stat sig change in RSS (as measured by `time -l`):
base diff difference (95% CI)
time 998038627.097 ± 13567305.958 1003327715.556 ± 15210451.236 [ -0.2% .. +1.2%]
samples 31 36
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D118797
- If not using `llvm-config`, `LLVM_MAIN_SRC_DIR` now has a sane default
- `LLVM_CONFIG_PATH` will continue to work for LLD for back compat.
- More quoting of paths in an abundance of caution.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D118792
In the case your framework bundles contain relocatable objects, and your
objects include LC_LINKER_OPTIONs for the framework, previously they
would not be deduplicated like they would have if they were static
archives. This was also the case if you passed `-framework` for the
framework as well.
Reviewed By: #lld-macho, thakis, oontvoo
Differential Revision: https://reviews.llvm.org/D114841
This updates all the non-runtime project release notes to use the
version number from CMake instead of the hard-coded version numbers
in conf.py.
It also hides warnings about pre-releases when the git suffix
is dropped from the LLVM version in CMake.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D112181
This diff adds support for ADRP+ADD optimization for AArch64 described in
d2ca58c54b
i.e. under appropriate constraints
ADRP x0, symbol
ADD x0, x0, :lo12: symbol
can be turned into
NOP
ADR x0, symbol
Test plan: make check-all
Differential revision: https://reviews.llvm.org/D117614
Added some comments (particularly around finalize() and
finalizeContents()) as well as doing some rephrasing / grammar fixes for
existing comments.
Also did some minor style fixups, such as by putting methods together in
a class definition and having fields of similar types next to each
other.
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D118714
See the updated insert-before.test for the effects: many synthetic
sections are SHF_ALLOC|SHF_WRITE. If they are discarded, we don't want
to propagate their flags to subsequent output section descriptions.
`getFirstInputSection(sec) == nullptr` can technically be merged into
`isDiscardable` but I'd like to postpone that as not sharing code may give more
refactoring opportunity.
Depends on D118529.
Reviewed By: peter.smith, bluca
Differential Revision: https://reviews.llvm.org/D118530
adjustSectionsBeforeSorting updates some output section attributes
(alignment/flags) and removes discardable empty sections. When it is called,
INSERT commands have not been processed. Therefore the flags propagation rule
may not affect output sections defined in an INSERT command properly.
Fix this by moving processInsertCommands before adjustSectionsBeforeSorting.
adjustSectionsBeforeSorting is somewhat misnamed. The order between it and
sortInputSections does not matter. With the pass shuffle, the name of
adjustSectionsBeforeSorting becomes wrong. Therefore rename it. The new
name is not set into stone. The function mixes several tasks and the
code may be refactored in a way that we may give them more meaningful
names.
With this patch, I think the behavior of attribute propagation becomes more
reasonable. In particular, in the absence of non-INSERT SECTIONS,
inserting a section after a SHF_ALLOC one will give us a SHF_ALLOC section,
not a non-SHF_ALLOC one (see linkerscript/insert-after.test).
Reviewed By: peter.smith, bluca
Differential Revision: https://reviews.llvm.org/D118529
The deduplication requires a DenseMap of the same size of the local part of
.strtab . I optimized it in e205445434 but it is
still quite slow.
For Release build of clang, deduplication makes .strtab 1.1% smaller and makes the link 3% slower.
For chrome, deduplication makes .strtab 0.1% smaller and makes the link 6% slower.
I suggest that we only perform the optimization with -O2 (default is -O1).
Not deduplicating local symbol names will simplify parallel symbol table write.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D118577
Replace `f<ELFT>(x)` with `InvokeELFT(f, x)`.
The size reduction comes from turning `link` from 4 specializations into 1.
My x86-64 lld executable is 26KiB smaller.
Reviewed By: ikudrin
Differential Revision: https://reviews.llvm.org/D118551
Previously an InputSectionBase is dead (`partition==0`) by default.
SyntheticSection calls markLive and BssSection overrides that with markDead.
It is more natural to make InputSectionBase live by default and let
--gc-sections mark InputSectionBase dead.
When linking a Release build of clang:
* --no-gc-sections:, the removed `inputSections` loop decreases markLive time from 4ms to 1ms.
* --gc-sections: the extra `inputSections` loop increases markLive time from 0.181296s to 0.188526s.
This is as of we lose the removing one `inputSections` loop optimization (4374824ccf).
I believe the loss can be mitigated if we refactor markLive.
This is a ld64 option equivalent to `-sectcreate seg sect /dev/null`
that's useful for creating sections like the RESTRICT section.
Differential Revision: https://reviews.llvm.org/D117749
Previously functions that aren't included in the symtab were also
excluded from the function starts. Symbols missing from function starts
degrades the debugger experience in the case you don't have debug info
for them.
Differential Revision: https://reviews.llvm.org/D114275
* `RelocationBaseSection::addReloc` increases `numRelativeRelocs`, which
duplicates the work done by RelocationSection<ELFT>::writeTo.
* --pack-dyn-relocs=android has inappropropriate DT_RELACOUNT.
AndroidPackedRelocationSection does not necessarily place relative relocations
in the front and DT_RELACOUNT might cause semantics error (though our
implementation doesn't and Android bionic doesn't use DT_RELACOUNT anyway.)
Move `llvm::partition` to a new function `partitionRels` and compute
`numRelativeRelocs` there. Now `RelocationBaseSection::addReloc` is trivial and
can be moved to the header to enable inlining.
The rest of DynamicReloc and `-z combreloc` handling is moved to the
non-template `RelocationBaseSection::computeRels` to decrease code size. My
x86-64 lld executable is 44+KiB smaller.
While here, rename `sort` to `combreloc`.
When processing dependent libraries, if there's a directory of the same
name as the library being searched for, either in the current directory
or earlier in the search order, LLD will try to open it and report an
error. This is because LLD uses file existence check. To address this
issue we reverse the order, searching the library by basename first
and only considering search paths later, and current directory last.
Differential Revision: https://reviews.llvm.org/D118498
Close#52781: for LTO, the inline asm diagnostic uses `<inline asm>` as the file
name (lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp) and it is unclear which
module has the issue.
With this patch, we will see the module name (say `asm.o`) before `<inline asm>` with ThinLTO.
```
% clang -flto=thin -c asm.c && myld.lld asm.o -e f
ld.lld: error: asm.o <inline asm>:1:2: invalid instruction mnemonic 'invalid'
invalid
^~~~~~~
```
For regular LTO, unfortunately the original module name is lost and we only get
ld-temp.o.
Reviewed By: #lld-macho, ychen, Jez Ng
Differential Revision: https://reviews.llvm.org/D118434
In older versions of llvm (e.g. llvm 13), symbols were not individually
flagged as TLS. In this case, the indent was to implicitly mark any
symbols defined in TLS segments as TLS. However, we were not performing
this implicit conversion if the segment was explicitly marked as TLS
As it happens, llvm 13 was branched between the addition of the segment
flag and the addition of the symbol flag. See:
- segment flag added: https://reviews.llvm.org/D102202
- symbol flag added: https://reviews.llvm.org/D109426
Testing this is tricky because the assembler will imply the TLS status
of the symbol based on the segment its declared in, so we are forced to
use a yaml file here.
Fixes: https://github.com/emscripten-core/emscripten/issues/15891
Differential Revision: https://reviews.llvm.org/D118414
This reverts commit ef82063207.
- It conflicts with the existing llvm::size in STLExtras, which will now
never be called.
- Calling it without llvm:: breaks C++17 compat
To fix
../../chromeclang/bin/../include/c++/v1/__algorithm/min.h:39:1: note: candidate template ignored: deduced conflicting types for parameter '_Tp' ('unsigned long' vs. 'unsigned long long')
on macOS arm64.
In start-end.s there is a lit check line `# SEG: _main` to begin the
check at the start of the function main where `_main` is the Darwin name
mangling for C main. Because the text file that FileCheck is getting as
input has the path of the compiler build in it from llvm-mc and
llvm-objdump, and because of the lack of a trailing colon in this check
line we end up inadvertently matching against the line of text with the
compiler path in it in the case where said path contains "_main" some
place. This can be very likely if the compiler branch has "main" or
"_main" in it.
To fix this I include the training : since that will match on the
function label and not the path line.
When linking a Debug build clang (265MiB SHF_ALLOC sections, 920MiB uncompressed
debug info), in a --threads=1 link "Compress debug sections" takes 2/3 time and
in a --threads=8 link "Compress debug sections" takes ~70% time.
This patch splits a section into 1MiB shards and calls zlib `deflake` parallelly.
DEFLATE blocks are a bit sequence. We need to ensure every shard starts
at a byte boundary for concatenation. We use Z_SYNC_FLUSH for all shards
but the last to flush the output to a byte boundary. (Z_FULL_FLUSH can
be used as well, but Z_FULL_FLUSH clears the hash table which just
wastes time.)
The last block requires the BFINAL flag. We call deflate with Z_FINISH
to set the flag as well as flush the output to a byte boundary. Under
the hood, all of Z_SYNC_FLUSH, Z_FULL_FLUSH, and Z_FINISH emit a
non-compressed block (called stored block in zlib). RFC1951 says "Any
bits of input up to the next byte boundary are ignored."
In a --threads=8 link, "Compress debug sections" is 5.7x as fast and the total
speed is 2.54x. Because the hash table for one shard is not shared with the next
shard, the output is slightly larger. Better compression ratio can be achieved
by preloading the window size from the previous shard as dictionary
(`deflateSetDictionary`), but that is overkill.
```
# 1MiB shards
% bloaty clang.new -- clang.old
FILE SIZE VM SIZE
-------------- --------------
+0.3% +129Ki [ = ] 0 .debug_str
+0.1% +105Ki [ = ] 0 .debug_info
+0.3% +101Ki [ = ] 0 .debug_line
+0.2% +2.66Ki [ = ] 0 .debug_abbrev
+0.0% +1.19Ki [ = ] 0 .debug_ranges
+0.1% +341Ki [ = ] 0 TOTAL
# 2MiB shards
% bloaty clang.new -- clang.old
FILE SIZE VM SIZE
-------------- --------------
+0.2% +74.2Ki [ = ] 0 .debug_line
+0.1% +72.3Ki [ = ] 0 .debug_str
+0.0% +69.9Ki [ = ] 0 .debug_info
+0.1% +976 [ = ] 0 .debug_abbrev
+0.0% +882 [ = ] 0 .debug_ranges
+0.0% +218Ki [ = ] 0 TOTAL
```
Bonus in not using zlib::compress
* we can compress a debug section larger than 4GiB
* peak memory usage is lower because for most shards the output size is less
than 50% input size (all less than 55% for a large binary I tested, but
decreasing the initial output size does not decrease memory usage)
Reviewed By: ikudrin
Differential Revision: https://reviews.llvm.org/D117853
This is in preparation for moving the code that parses and processes
order files into this file.
See https://reviews.llvm.org/D117354 for context and discussion.
Notation: dst is `t->getThunkTargetSym()->getVA()`
On AArch64, when `src-0x8000000-r_addend <= dst < src-0x8000000`, the condition
`target->inBranchRange(rel.type, src, rel.sym->getVA(rel.addend))` may
incorrectly consider a thunk reusable.
`rel.addend = -getPCBias(rel.type)` resets the addend to 0 for AArch64/PPC
and the zero addend is used by `rel.sym->getVA(rel.addend)` to check
out-of-range relocations.
See the test for a case this computation is wrong:
`error: a.o:(.text_high+0x4): relocation R_AARCH64_JUMP26 out of range: -134217732 is not in [-134217728, 134217727]`
I have seen a real world case with r_addend=19960.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D117734
Only using that change in StringRef already decreases the number of
preoprocessed lines from 7837621 to 7776151 for LLVMSupport
Perhaps more interestingly, it shows that many files were relying on the
inclusion of StringRef.h to have the declaration from STLExtras.h. This
patch tries hard to patch relevant part of llvm-project impacted by this
hidden dependency removal.
Potential impact:
- "llvm/ADT/StringRef.h" no longer includes <memory>,
"llvm/ADT/Optional.h" nor "llvm/ADT/STLExtras.h"
Related Discourse thread:
https://llvm.discourse.group/t/include-what-you-use-include-cleanup/5831
D54759 introduced aarch64-combined-dynrel.s and
aarch64-combined-dynrel-ifunc.s . Unfortunately the requires line
at the top was AArch64 instead of aarch64 which means they were never
run. Update the tests to use aarch64 and fix to match current lld output.
Differential Revision: https://reviews.llvm.org/D117896
Unresolved symbols are not currently reported when building with
`-shared` or `-pie` so setting unresolvedSymbols doesn't have any
effect.
Differential Revision: https://reviews.llvm.org/D117737
Its defaulting logic must go after `project(..)` to work correctly, but `project(..)` is often in a standalone condition making this
awkward, since the rest of the condition code may also need GNUInstallDirs.
The good thing is there are the various standalone booleans, which I had missed before. This makes splitting the conditional blocks less awkward.
Reviewed By: arichardson, phosek, beanz, ldionne, #libunwind, #libc, #libc_abi
Differential Revision: https://reviews.llvm.org/D117639
StringRefZ does not improve performance. Non-local symbols always have eagerly
computed nameSize. Most local symbols's lengths will be updated in either:
* shouldKeepInSymtab
* SymbolTableBaseSection::addSymbol
Its benefit is offsetted by strlen in every call site (sums up to 5KiB code in a
release x86-64 build), so using StringRefZ may be slower.
In a -s link (uncommon) there is minor speedup, like ~0.3% for clang and chrome.
Reviewed By: alexander-shaposhnikov
Differential Revision: https://reviews.llvm.org/D117644
This patch writes the full -cc1 command into the resulting .OBJ, like MSVC does. This allows for external tools (Recode, Live++) to rebuild a source file without any external dependency but the .OBJ itself (other than the compiler) and without knowledge of the build system.
The LF_BUILDINFO record stores a full path to the compiler, the PWD (CWD at program startup), a relative or absolute path to the source, and the full CC1 command line. The stored command line is self-standing (does not depend on the environment). In the same way, MSVC doesn't exactly store the provided command-line, but an expanded version (a somehow equivalent of CC1) which is also self-standing.
For more information see PR36198 and D43002.
Differential Revision: https://reviews.llvm.org/D80833
If you're building this on macOS 12.x+ this produces a deprecation
warning. I'm not sure what this means for the bitcode format going
forward, but it seems safe to silence for now.
Do we need to worry about GCC for this?
Differential Revision: https://reviews.llvm.org/D117718
This flag is the default, so in ld64 it is not implemented, but it can
be useful to negate previous -all_load arguments. Specifically if your
build system has some global linker flags, that you may want to negate
for specific links. We use something like this today to make sure some
C++ symbols are automatically discovered for all links, which passing
-all_load hides.
Differential Revision: https://reviews.llvm.org/D117629
Fix a regression after aabe901d57 (`[ELF] Remove
one redundant computeBinding`): isLocal() does not indicate that the symbol is
originally local. For simplicity, just drop this optimization.
In ld.lld, when an ObjFile/BitcodeFile is read in --start-lib state, the file is
given archive semantics. --end-lib closes the previous --start-lib. A build
system can use this feature as an alternative to archives. This patch ports
the feature to lld-macho.
--start-lib and --end-lib are positional, unlike usual ld64 options.
I think the slight drawback does not matter as (a) reusing option names
make build systems convenient (b) `--start-lib a.o b.o --end-lib` conveys more
information than an alternative design: `-objlib a.o -objlib b.o` because
--start-lib makes it clear which objects are in the same conceptual archive.
This provides flexibility (c) `-objlib`/`-filelist` interaction may be weird.
Close https://github.com/llvm/llvm-project/issues/52931
Reviewed By: #lld-macho, Jez Ng, oontvoo
Differential Revision: https://reviews.llvm.org/D116913
When an archive with an empty index contains only bitcode files, it is
handled as a group of lazy (--start-lib) object files. If there is a
non-bitcode file, there will be a diagnostic a la GNU ld.
For some programs, the archive member extraction ratio is high (e.g. for chrome,
79% archive members are extracted according to --print-archive-stats=). Because
symbol interning is cached for ObjFile::parseLazy but not for ArchiveFile,
parsing an archive as a group of --start-lib object files may be faster.
If the linker speculatively creates section representations for archive members,
the archive index will not be used.
If we take the above view, the archive index is essentially useless. If a user
wants a fast build without using --start-lib, they may just build thin archives
without index (`ar rcS --thin`).
Therefore, I suggest that we no longer treat the code as a hack, instead as a
supported feature. I believe we will do this anyway if we add parallel symbol
interning (parallel symbol interning for lazy object files is simpler than that
for archives).
Ecosystem issues:
* parseLazy actually has nearly the same behavior as ArchiveFile::parse, but the symbol order may be different.
* users may get addicted to the behavior and build archives not working with GNU ld and gold. I think it is easy to rebuild archives to be compatible.
Reviewed By: ikudrin
Differential Revision: https://reviews.llvm.org/D117284
D46245 added support for this in llvm-libtool, but while lld-link can
also create .lib files from .def files it didn't support aliases.
I compared the Inputs/library.def test against the output from
llvm-libtool and it matches, except for the fact that lld-link reorders
functions for some reason.
I have also verified that this fixes a bug I was running into while
trying to compile .def files to .lib files in MinGW-w64 (using lld-link
instead of llvm-libtool).
Differential Revision: https://reviews.llvm.org/D113365
This simplifies the code a bit. While here,
* change the `multiple relocation sections` diagnostic from `fatal` to `error` and include the relocated section name.
* drop less useful name from `getRelocTarget`. Without -r/--emit-relocs we don't need to get SHT_REL/SHT_RELA names.
It's still uncertain but whether we want to have `deduplicate-literals` be the
default flag for LLD out of the box or not. If `deduplicate-literals` is the default
behavior, then we will need a way override it and not deduplicate. Luckily, we
have `no_deduplicate` to fill this gap. For now, I've set the default to be false
which aligns with the existing behavior. That can only always be changed after
discussions on D117250.
Reviewed By: #lld-macho, int3
Differential Revision: https://reviews.llvm.org/D117387
We already perform memory initialization and apply global relocations
during start. It makes sense to performs data relocations too. I think
the reason we were not doing this already is solely historical.
Differential Revision: https://reviews.llvm.org/D117412
After the D33630 fallout was properly fixed by a4c5db30be.
Tested by D37462/D44986 tests, the new --no-rosegment test in build-id.s, and a few --rosegment/--no-rosegment programs.
Move all variables at file-scope or function-static-scope into a hosting structure (lld::CommonLinkerContext) that lives at lldMain()-scope. Drivers will inherit from this structure and add their own global state, in the same way as for the existing COFFLinkerContext.
See discussion in https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html
Differential Revision: https://reviews.llvm.org/D108850
Sorting dynamic relocations is a bottleneck. Simplifying the comparator improves
performance. Linking clang is 4~5% faster with --threads=8.
This change may shuffle R_MIPS_REL32 for Mips and is a NFC for non-Mips.
Tail merge is slow and of low value. With regular string deduplication, we can
just use the return value of StringTableBuilder::add.
There is no noticeable performance increase because without deduplication
`__cstring` is quite small (7.6MiB for chromium_framework).
Reviewed By: #lld-macho, Jez Ng
Differential Revision: https://reviews.llvm.org/D117273
The PlatformKind/PlatformType enums contain the same information, which requires
them to be kept in-sync. This commit changes over to PlatformType as the sole
source of truth, which allows the removal of the redundant PlatformKind.
The majority of the changes were in LLD and TextAPI.
Reviewed By: cishida
Differential Revision: https://reviews.llvm.org/D117163
This extends D81784. Sections can be discarded when linking a
relocatable output. Before the patch, LLD did not update the content
of debug sections and only replaced the corresponding relocations with
R_*_NONE, which could break the debug information.
Differential Revision: https://reviews.llvm.org/D116946
db08df0570 does not work because part.relrDyn is
a unique_ptr and `reset` destroys the object which may still be referenced.
This commit uses the D114180 approach. Also improve the test to check that there
is no R_X86_64_RELATIVE.
Fix https://github.com/llvm/llvm-project/issues/53073
In case of a relocation error, GNU ld's link map includes
the archive member extraction information but not output sections.
Our -Map and --why-extract= are currently no-op in case of an error.
This change makes the two options work.
Reviewed By: ikudrin, peter.smith
Differential Revision: https://reviews.llvm.org/D116838
to prepare for D116838, otherwise for linkerscript/discard-section-err.s,
there will be a null pointer dereference in `part.relrDyn->getParent()->size`
in `finalizeSynthetic(part.relrDyn.get())`.
Depends on D112160
This adds the new options `--call-graph-profile-sort` (default),
`--no-call-graph-profile-sort` and `--print-symbol-order=`. If call graph
profile sorting is enabled, reads `__LLVM,__cg_profile` sections from object
files and uses the resulting graph to put callees and callers close to each
other in the final binary via the C3 clustering heuristic.
Differential Revision: https://reviews.llvm.org/D112164
rG1bb0caf56168 changed the datalayout of f80 on Windows 32 bits. But it
missed the related use in the LLD tests. This patch will fix the
problem catched by buildbot.
After {D117069}, map-file.s seems flaky. It seems that the "Total Write
map file" section always exists, but the "Write map file" sub-section
may or may not be emitted. So we check for the former.
After {D115416}, the "Write map file" event no longer shows up
in the time trace. Each time trace profiler instance is thread-local,
but we had neglected to initialize a separate instance for the mapfile
worker thread.
Reviewed By: keith
Differential Revision: https://reviews.llvm.org/D117069
D116913 will add LazyObject. Rename LazySymbol to LazyArchive to avoid confusion
and mirror ELF.
Reviewed By: #lld-macho, Jez Ng
Differential Revision: https://reviews.llvm.org/D116914
Currently the way some relocation-related static functions pass around
states is clumsy. Add a Resolver class to store some states as member
variables.
Advantages:
* Avoid the parameter `InputSectionBase &sec` (this offsets the cost passing around `this` paramemter)
* Avoid the parameter `end` (Mips and PowerPC hacks)
* `config` and `target` can be cached as member variables to reduce global state accesses. (potential speedup because the compiler didn't know `config`/`target` were not changed across function calls)
* If we ever want to reduce if-else costs (e.g. `config->emachine==EM_MIPS` for non-Mips) or introduce parallel relocation scan not handling some tricky arches (PPC/Mips), we can templatize Resolver
`target` isn't used as much as `config`, so I change it to a const reference
during the migration.
There is a minor performance inprovement for elf::scanRelocations.
Reviewed By: ikudrin, peter.smith
Differential Revision: https://reviews.llvm.org/D116881
When `file->fetch(sym)` is replaced with a no-op, no test fails.
The new test catches the case.
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D116916
We only support both TLSDESC and TLS GD for x86 so this is an x86-specific
problem. If both are used, only one R_X86_64_TLSDESC is produced and TLS GD
accesses will incorrectly reference R_X86_64_TLSDESC. Fix this by introducing
SymbolAux::tlsDescIdx.
Reviewed By: ikudrin
Differential Revision: https://reviews.llvm.org/D116900
Fangrui Song