[lld-macho] Implement -hidden-l

Similarly to -load_hidden, this flag instructs the linker to not export
symbols from the specified archive. While that flag takes a path,
-hidden-l looks for the spec

[lld-macho] Implement -hidden-l

Similarly to -load_hidden, this flag instructs the linker to not export
symbols from the specified archive. While that flag takes a path,
-hidden-l looks for the specified library name in the search path.

The test changes are needed because -hidden-lfoo resolves to libfoo.a,
not foo.a.

Differential Revision: https://reviews.llvm.org/D130529

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Reland "[lld-macho] Implement -load_hidden"

This flag was introduced in ld64-609. It instructs the linker to link to
a static library while treating its symbols as if they had hidden
visibility. Thi

Reland "[lld-macho] Implement -load_hidden"

This flag was introduced in ld64-609. It instructs the linker to link to
a static library while treating its symbols as if they had hidden
visibility. This is useful when building a dylib that links to static
libraries but we don't want the symbols from those to be exported.

Closes #51505

This reland adds bitcode file handling, so we won't get any compile
errors due to BitcodeFile::forceHidden being unused.

Differential Revision: https://reviews.llvm.org/D130473

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Revert "[lld-macho] Implement -load_hidden"

This reverts commit 4c79e1a3f4eb790f40239833ae237e828ce07386.

Broke this bot: https://lab.llvm.org/buildbot/#builders/57/builds/20319

[lld-macho] Implement -load_hidden

This flag was introduced in ld64-609. It instructs the linker to link to
a static library while treating its symbols as if they had hidden
visibility. This is usef

[lld-macho] Implement -load_hidden

This flag was introduced in ld64-609. It instructs the linker to link to
a static library while treating its symbols as if they had hidden
visibility. This is useful when building a dylib that links to static
libraries but we don't want the symbols from those to be exported.

Closes #51505

Differential Revision: https://reviews.llvm.org/D130473

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[lld-macho] Fold __objc_imageinfo sections

Previously, we treated it as a regular ConcatInputSection. However, ld64
actually parses its contents and uses that to synthesize a single image
info struc

[lld-macho] Fold __objc_imageinfo sections

Previously, we treated it as a regular ConcatInputSection. However, ld64
actually parses its contents and uses that to synthesize a single image
info struct, generating one 8-byte section instead of `8 * number of
object files with ObjC code`.

I'm not entirely sure what impact this section has on the runtime, so I
just tried to follow ld64's semantics as closely as possible in this
diff. My main motivation though was to reduce binary size.

No significant perf change on chromium_framework on my 16-core Mac Pro:

base diff difference (95% CI)
sys_time 1.764 ± 0.062 1.748 ± 0.032 [ -2.4% .. +0.5%]
user_time 5.112 ± 0.104 5.106 ± 0.046 [ -0.9% .. +0.7%]
wall_time 6.111 ± 0.184 6.085 ± 0.076 [ -1.6% .. +0.8%]
samples 30 32

Reviewed By: #lld-macho, thakis

Differential Revision: https://reviews.llvm.org/D130125

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[lld-macho] Fold cfstrings with --deduplicate-literals

Similar to cstrings ld64 always deduplicates cfstrings. This was already
being done when enabling ICF, but for debug builds you may want to fli

[lld-macho] Fold cfstrings with --deduplicate-literals

Similar to cstrings ld64 always deduplicates cfstrings. This was already
being done when enabling ICF, but for debug builds you may want to flip
this on if you cannot eliminate your instances of this, so this change
makes --deduplicate-literals also apply to cfstrings.

Differential Revision: https://reviews.llvm.org/D130134

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Use llvm::is_contained (NFC)

[lld-macho] Simplify archive loading logic

This is a follow-on to {D129556}. I've refactored the code such that
`addFile()` no longer needs to take an extra parameter. Additionally,
the "do we force

[lld-macho] Simplify archive loading logic

This is a follow-on to {D129556}. I've refactored the code such that
`addFile()` no longer needs to take an extra parameter. Additionally,
the "do we force-load or not" policy logic is now fully contained within
addFile, instead of being split between `addFile` and
`parseLCLinkerOptions`. This also allows us to move the `ForceLoad` (now
`LoadType`) enum out of the header file.

Additionally, we can now correctly report loads induced by
`LC_LINKER_OPTION` in our `-why_load` output.

I've also added another test to check that CLI library non-force-loads
take precedence over `LC_LINKER_OPTION` + `-force_load_swift_libs`. (The
existing logic is correct, just untested.)

Reviewed By: #lld-macho, thakis

Differential Revision: https://reviews.llvm.org/D130137

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[lld-macho] Fix loading same libraries from both LC_LINKER_OPTION and command line

This fixes https://github.com/llvm/llvm-project/issues/56059 and
https://github.com/llvm/llvm-project/issues/56440.

[lld-macho] Fix loading same libraries from both LC_LINKER_OPTION and command line

This fixes https://github.com/llvm/llvm-project/issues/56059 and
https://github.com/llvm/llvm-project/issues/56440. This is inspired by
tapthaker's patch (https://reviews.llvm.org/D127941), and has reused his
test cases. This patch adds an bool "isCommandLineLoad" to indicate
where archives are from. If lld tries to load the same library loaded
previously by LC_LINKER_OPTION from CLI, it will use this
isCommandLineLoad to determine if it should be affected by -all_load &
-ObjC flags. This also prevents -force_load from affecting archives
loaded previously from CLI without such flag, whereas tapthaker's patch
will fail such test case (introduced by
https://reviews.llvm.org/D128025).

Reviewed By: int3, #lld-macho

Differential Revision: https://reviews.llvm.org/D129556

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[lld-macho] Add support for -alias

This creates a symbol alias similar to --defsym in the elf linker. This
is used by swiftpm for all executables, so it's useful to support. This
doesn't implement -

[lld-macho] Add support for -alias

This creates a symbol alias similar to --defsym in the elf linker. This
is used by swiftpm for all executables, so it's useful to support. This
doesn't implement -alias_list but that could be done pretty easily as
needed.

Differential Revision: https://reviews.llvm.org/D129938

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[lld-macho] Enable EH frame relocation / pruning

This just removes the code that gates the logic. The main issue here is
perf impact: without {D122258}, LLD takes a significant perf hit because
it n

[lld-macho] Enable EH frame relocation / pruning

This just removes the code that gates the logic. The main issue here is
perf impact: without {D122258}, LLD takes a significant perf hit because
it now has to do a lot more work in the input parsing phase. But with
that change to eliminate unnecessary EH frames from input object files,
the perf overhead here is minimal. Concretely, here are the numbers for
some builds as measured on my 16-core Mac Pro:

**chromium_framework**

This is without the use of `-femit-dwarf-unwind=no-compact-unwind`:

base diff difference (95% CI)
sys_time 1.826 ± 0.019 1.962 ± 0.034 [ +6.5% .. +8.4%]
user_time 9.306 ± 0.054 9.926 ± 0.082 [ +6.2% .. +7.1%]
wall_time 8.225 ± 0.068 8.947 ± 0.128 [ +8.0% .. +9.6%]
samples 15 22

With that flag enabled, the regression mostly disappears, as hoped:

base diff difference (95% CI)
sys_time 1.839 ± 0.062 1.866 ± 0.068 [ -0.9% .. +3.8%]
user_time 9.452 ± 0.068 9.490 ± 0.067 [ -0.1% .. +0.9%]
wall_time 8.383 ± 0.127 8.452 ± 0.114 [ -0.1% .. +1.8%]
samples 17 21

**Unnamed internal app**

Without `-femit-dwarf-unwind`, this is the perf hit:

base diff difference (95% CI)
sys_time 1.372 ± 0.029 1.317 ± 0.024 [ -4.6% .. -3.5%]
user_time 2.835 ± 0.028 2.980 ± 0.027 [ +4.8% .. +5.4%]
wall_time 3.205 ± 0.079 3.383 ± 0.066 [ +4.9% .. +6.2%]
samples 102 83

With `-femit-dwarf-unwind`, the perf hit almost disappears:

base diff difference (95% CI)
sys_time 1.274 ± 0.026 1.270 ± 0.025 [ -0.9% .. +0.3%]
user_time 2.812 ± 0.023 2.822 ± 0.035 [ +0.1% .. +0.7%]
wall_time 3.166 ± 0.047 3.174 ± 0.059 [ -0.2% .. +0.7%]
samples 95 97

Just for fun, I measured the impact of `-femit-dwarf-unwind` on ld64
(`base` has the extra DWARF unwind info in the input object files,
`diff` doesn't):

base diff difference (95% CI)
sys_time 1.128 ± 0.010 1.124 ± 0.023 [ -1.3% .. +0.6%]
user_time 7.176 ± 0.030 7.106 ± 0.094 [ -1.5% .. -0.4%]
wall_time 7.874 ± 0.041 7.795 ± 0.121 [ -1.7% .. -0.3%]
samples 16 25

And for LLD:

base diff difference (95% CI)
sys_time 1.315 ± 0.019 1.280 ± 0.019 [ -3.2% .. -2.0%]
user_time 2.980 ± 0.022 2.822 ± 0.016 [ -5.5% .. -5.0%]
wall_time 3.369 ± 0.038 3.175 ± 0.033 [ -6.2% .. -5.3%]
samples 47 47

So parsing the extra EH frames is a lot more expensive for us than for
ld64. But given that we are quite a lot faster than ld64 to begin with,
I guess this isn't entirely unexpected...

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D129540

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[lld-macho] Initial support for Linker Optimization Hints

Linker optimization hints mark a sequence of instructions used for
synthesizing an address, like ADRP+ADD. If the referenced symbol ends up

[lld-macho] Initial support for Linker Optimization Hints

Linker optimization hints mark a sequence of instructions used for
synthesizing an address, like ADRP+ADD. If the referenced symbol ends up
close enough, it can be replaced by a faster sequence of instructions
like ADR+NOP.

This commit adds support for 2 of the 7 defined ARM64 optimization
hints:
- LOH_ARM64_ADRP_ADD, which transforms a pair of ADRP+ADD into ADR+NOP
if the referenced address is within +/- 1 MiB
- LOH_ARM64_ADRP_ADRP, which transforms two ADRP instructions into
ADR+NOP if they reference the same page

These two kinds already cover more than 50% of all LOHs in
chromium_framework.

Differential Review: https://reviews.llvm.org/D128093

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[lld, ELF and mac] Add --time-trace=<file>, remove --time-trace-file=<file>

`--time-trace=foo` has the same behavior as `--time-trace --time-trace-file=<file>`
had previously.

Also, for mac, make -

[lld, ELF and mac] Add --time-trace=<file>, remove --time-trace-file=<file>

`--time-trace=foo` has the same behavior as `--time-trace --time-trace-file=<file>`
had previously.

Also, for mac, make --time-trace-granularity *not* imply --time-trace, to match
behavior of the ELF port.

Differential Revision: https://reviews.llvm.org/D128451

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[lld/mac] Add a few TimeTraceScopes

Identical literal folding takes ~1.4% of the time, and was missing
from the trace.

Signature computation still needs ~2.2% of the time, so probably worth
explici

[lld/mac] Add a few TimeTraceScopes

Identical literal folding takes ~1.4% of the time, and was missing
from the trace.

Signature computation still needs ~2.2% of the time, so probably worth
explicitly marking its contribution to "Write output file" (9.1%)

Differential Revision: https://reviews.llvm.org/D128343

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[lld-macho] Add support for exporting no symbols

As an optimization for ld64 sometimes it can be useful to not export any
symbols for top level binaries that don't need any exports, to do this
you c

[lld-macho] Add support for exporting no symbols

As an optimization for ld64 sometimes it can be useful to not export any
symbols for top level binaries that don't need any exports, to do this
you can pass `-exported_symbols_list /dev/null`, or new with Xcode 14
(ld64 816) there is a `-no_exported_symbols` flag for the same behavior.
This reproduces this behavior where previously an empty exported symbols
list file would have been ignored.

Differential Revision: https://reviews.llvm.org/D127562

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[lld-macho][reland] Initial support for EH Frames

This reverts commit 942f4e3a7cc9a9f8b2654817cff12907d1276031.

The additional change required to avoid the assertion errors seen
previously is:

-

[lld-macho][reland] Initial support for EH Frames

This reverts commit 942f4e3a7cc9a9f8b2654817cff12907d1276031.

The additional change required to avoid the assertion errors seen
previously is:

--- a/lld/MachO/ICF.cpp
+++ b/lld/MachO/ICF.cpp
@@ -443,7 +443,9 @@ void macho::foldIdenticalSections() {
/*relocVA=*/0);
isec->data = copy;
}
- } else {
+ } else if (!isEhFrameSection(isec)) {
+ // EH frames are gathered as hashables from unwindEntry above; give a
+ // unique ID to everything else.
isec->icfEqClass[0] = ++icfUniqueID;
}
}

Differential Revision: https://reviews.llvm.org/D123435

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Revert "[lld-macho] Initial support for EH Frames"

This reverts commit 826be330af9c0a8553a5b32718ecd2d97e10438e.

This was causing a test failure on build bots:
- https://lab.llvm.org/buildbot/#/b

Revert "[lld-macho] Initial support for EH Frames"

This reverts commit 826be330af9c0a8553a5b32718ecd2d97e10438e.

This was causing a test failure on build bots:
- https://lab.llvm.org/buildbot/#/builders/36/builds/21770
- https://lab.llvm.org/buildbot/#/builders/58/builds/23913

show more ...

[lld-macho] Initial support for EH Frames

== Background ==

`llvm-mc` generates unwind info in both compact unwind and DWARF
formats. LLD already handles the compact unwind format; this diff gets
us

[lld-macho] Initial support for EH Frames

== Background ==

`llvm-mc` generates unwind info in both compact unwind and DWARF
formats. LLD already handles the compact unwind format; this diff gets
us close to handling the DWARF format properly.

== Caveats ==

It's not quite done yet, but I figure it's worth getting this reviewed
and landed first as it's shaping up to be a fairly large code change.

**Known limitations of the current code:**

* Only works for x86_64, for which `llvm-mc` emits "abs-ified"
relocations as described in https://github.com/llvm/llvm-project/commit/618def651b59bd42c05bbd91d825af2fb2145683.
`llvm-mc` emits regular relocations for ARM EH frames, which we do not
yet handle correctly.

Since the feature is not ready for real use yet, I've gated it behind a
flag that only gets toggled on during test suite runs. With most of the
new code disabled, we see just a hint of perf regression, so I don't
think it'd be remiss to land this as-is:

base diff difference (95% CI)
sys_time 1.926 ± 0.168 1.979 ± 0.117 [ -1.2% .. +6.6%]
user_time 3.590 ± 0.033 3.606 ± 0.028 [ +0.0% .. +0.9%]
wall_time 7.104 ± 0.184 7.179 ± 0.151 [ -0.2% .. +2.3%]
samples 30 31

== Design ==

Like compact unwind entries, EH frames are also represented as regular
ConcatInputSections that get pointed to via `Defined::unwindEntry`. This
allows them to be handled generically by e.g. the MarkLive and ICF
code. (But note that unlike compact unwind subsections, EH frame
subsections do end up in the final binary.)

In order to make EH frames "look like" a regular ConcatInputSection,
some processing is required. First, we need to split the `__eh_frame`
section along EH frame boundaries rather than along symbol boundaries.
We do this by decoding the length field of each EH frame. Second, the
abs-ified relocations need to be turned into regular Relocs.

== Next Steps ==

In order to support EH frames on ARM targets, we will either have to
teach LLD how to handle EH frames with explicit relocs, or we can try to
make `llvm-mc` emit abs-ified relocs for ARM as well. I'm hoping to do
the latter as I think it will make the LLD implementation both simpler
and faster to execute.

== Misc ==

The `obj-file-with-stabs.s` test had to be updated as the previous
version would trip assertion errors in the code. It appears that in our
attempt to produce a minimal YAML test input, we created a file with
invalid EH frame data. I've fixed this by re-generating the YAML and not
doing any hand-pruning of it.

Reviewed By: #lld-macho, Roger

Differential Revision: https://reviews.llvm.org/D123435

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[lld-macho] Addressed additional post-commit comments from D126046

- fixed newlines
- renamed helper function for clarity
- added additional comment

Differential Revision: https://reviews.llvm.org

[lld-macho] Addressed additional post-commit comments from D126046

- fixed newlines
- renamed helper function for clarity
- added additional comment

Differential Revision: https://reviews.llvm.org/D126792

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[lld-macho] Support -non_global_symbols_strip_list, -non_global_symbols_no_strip_list, -x

PR/55600

Differential Revision: https://reviews.llvm.org/D126046

[lld-macho] Demangle symbol names in export-symbol error messages when -demangle is specified.
PR/55512

Reviewed By: keith

Differential Revision: https://reviews.llvm.org/D125732

[lld/mac] Support writing zippered dylibs and bundles

With -platform_version flags for two distinct platforms,
this writes a LC_BUILD_VERSION header for each.

The motivation is that this is needed

[lld/mac] Support writing zippered dylibs and bundles

With -platform_version flags for two distinct platforms,
this writes a LC_BUILD_VERSION header for each.

The motivation is that this is needed for self-hosting with lld as linker
after D124059.

To create a zippered output at the clang driver level, pass

-target arm64-apple-macos -darwin-target-variant arm64-apple-ios-macabi

to create a zippered dylib.

(In Xcode's clang, `-darwin-target-variant` is spelled just `-target-variant`.)

(If you pass `-target arm64-apple-ios-macabi -target-variant arm64-apple-macos`
instead, ld64 crashes!)

This results in two -platform_version flags being passed to the linker.

ld64 also verifies that the iOS SDK version is at least 13.1. We don't do that
yet. But ld64 also does that for other platforms and we don't. So we need to
do that at some point, but not in this patch.

Only dylib and bundle outputs can be zippered.

I verified that a Catalyst app linked against a dylib created with

clang -shared foo.cc -o libfoo.dylib \
-target arm64-apple-macos \
-target-variant arm64-apple-ios-macabi \
-Wl,-install_name,@rpath/libfoo.dylib \
-fuse-ld=$PWD/out/gn/bin/ld64.lld

runs successfully. (The app calls a function `f()` in libfoo.dylib
that returns a const char* "foo", and NSLog(@"%s")s it.)

ld64 is a bit more permissive when writing zippered outputs,
see references to "unzippered twins". That's not implemented yet.
(If anybody wants to implement that, D124275 is a good start.)

Differential Revision: https://reviews.llvm.org/D124887

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[lld] Implement safe icf for MachO

This change implements --icf=safe for MachO based on addrsig section that is implemented in D123751.

Reviewed By: int3, #lld-macho

Differential Revision: https:/

[lld] Implement safe icf for MachO

This change implements --icf=safe for MachO based on addrsig section that is implemented in D123751.

Reviewed By: int3, #lld-macho

Differential Revision: https://reviews.llvm.org/D123752

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[lld/mac] For catalyst outputs, tolerate implicitly linking against mac-only tbd files

Before this,

clang empty.cc -target x86_64-apple-ios13.1-macabi \
-framework CoreServices -fuse-ld=lld

[lld/mac] For catalyst outputs, tolerate implicitly linking against mac-only tbd files

Before this,

clang empty.cc -target x86_64-apple-ios13.1-macabi \
-framework CoreServices -fuse-ld=lld

would error out with

ld64.lld: error: path/to/MacOSX.sdk/System/Library/Frameworks/
CoreServices.framework/Versions/A/Frameworks/CarbonCore.framework/
Versions/A/CarbonCore.tbd(
/System/Library/Frameworks/
CoreServices.framework/Versions/A/Frameworks/CarbonCore.framework/
Versions/A/CarbonCore) is incompatible with x86_64 (macCatalyst)

Now it works, like with ld64.

Differential Revision: https://reviews.llvm.org/D124336

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[lld-macho] Fix crash on invalid framework tbd

Previously these would crash because `file` is null in the case there is
an invalid tbd file.

Differential Revision: https://reviews.llvm.org/D124271