Commit Graph

14631 Commits

Author SHA1 Message Date
Greg McGary 3a1b3c9afe [lld-macho][nfc] rename parsed-section types & variables
This is an NFC diff that prepares for pruning & relocating `__eh_frame`.

Along the way, I made the following changes to ...
* clarify usage of `section` vs. `subsection`
* remove `map` & `vec` from type names
* disambiguate class `Section` from template parameter `SectionHeader`.

Differential Revision: https://reviews.llvm.org/D113241
2021-11-16 07:06:41 -07:00
Quinn Pham 1ca00ecfb8 [NFC][lld] Inclusive language: change master file to merged file
[NFC] As part of using inclusive language within the llvm project, this patch
replaces master with merged in these comments.

Reviewed By: #lld-macho, thakis

Differential Revision: https://reviews.llvm.org/D113903
2021-11-15 14:32:09 -06:00
Igor Kudrin 66691de94c [ELF] Do not try to assign a memory region to a non-allocatable section
Non-allocatable sections are not part of the memory image of the
program, so there is no need to find memory regions for them either
matching properties or handling explicit assignments. The early test
and return help to simplify LinkerScript::findMemoryRegion() a bit.

Differential Revision: https://reviews.llvm.org/D113768
2021-11-15 15:59:39 +07:00
Shao-Ce SUN 0c660256eb [NFC] Trim trailing whitespace in *.rst 2021-11-15 09:17:08 +08:00
Keith Smiley 51715fbd96 [lld-macho] Fix warning
```
/Users/ksmiley/dev/llvm-project/lld/MachO/Symbols.cpp:43:27: warning: field 'external' will be initialized after field 'weakDefCanBeHidden' [-Wreorder-ctor]
      weakDef(isWeakDef), external(isExternal),
                          ^
1 warning generated.
```

Differential Revision: https://reviews.llvm.org/D113823
2021-11-12 19:36:51 -08:00
Vy Nguyen 9b29dae3ca [lld-macho] Allow exporting weak_def_can_be_hidden(AKA "autohide") symbols
autohide symbols behaves similarly to private_extern symbols.
However, LD64 allows exporting autohide symbols. LLD currently does not.
This patch allows LLD to export them.

Differential Revision: https://reviews.llvm.org/D113167
2021-11-12 21:57:30 -05:00
Vy Nguyen ad932320d8 [lld-macho] Parallelize scanning the symbol tables in export/unexport-ing.
(Split from D113167)
Benchmarking on one of our large apps which exports a few thousands symbols,
this showed an improvement of ~17%.

x ./LLD_no_parallel.txt
+ ./LLD_with_parallel.txt

    N           Min           Max        Median           Avg        Stddev
x  10         84.01         89.41         88.64        87.693     1.7424061
+  10          71.9         74.29         72.63        72.753    0.77734663
Difference at 95.0% confidence
	-14.94 +/- 1.26763
	-17.0367% +/- 1.44553%
	(Student's t, pooled s = 1.34912)

(wallclock)

Differential Revision: https://reviews.llvm.org/D113820
2021-11-12 20:57:24 -05:00
Duncan P. N. Exon Smith 9a2b54af22 lld: const-qualify iterations through VarStreamArray, NFC
No functionality change here; just unblocking a patch to LLVM.
2021-11-12 14:29:49 -08:00
Jez Ng 9d0b237c51 [lld-macho] Fix symbol relocs handling for LSDAs
Similar to D113702, but for the LSDAs. Clang seems to emit all LSDA
relocs as section relocs, but ld -r can turn those relocs into symbol
ones.

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D113721
2021-11-12 16:02:49 -05:00
Jez Ng d9b6f7e312 [lld-macho] Teach ICF to dedup functions with identical unwind info
Dedup'ing unwind info is tricky because each CUE contains a different
function address, if ICF operated naively and compared the entire
contents of each CUE, entries with identical unwind info but belonging
to different functions would never be considered identical. To work
around this problem, we slice away the function address before
performing ICF. We rely on `relocateCompactUnwind()` to correctly handle
these truncated input sections.

Here are the numbers before and after D109944, D109945, and this diff
were applied, as tested on my 3.2 GHz 16-Core Intel Xeon W:

Without any optimizations:

             base           diff           difference (95% CI)
  sys_time   0.849 ± 0.015  0.896 ± 0.012  [  +4.8% ..   +6.2%]
  user_time  3.357 ± 0.030  3.512 ± 0.023  [  +4.3% ..   +5.0%]
  wall_time  3.944 ± 0.039  4.032 ± 0.031  [  +1.8% ..   +2.6%]
  samples    40             38

With `-dead_strip`:

             base           diff           difference (95% CI)
  sys_time   0.847 ± 0.010  0.896 ± 0.012  [  +5.2% ..   +6.5%]
  user_time  3.377 ± 0.014  3.532 ± 0.015  [  +4.4% ..   +4.8%]
  wall_time  3.962 ± 0.024  4.060 ± 0.030  [  +2.1% ..   +2.8%]
  samples    47             30

With `-dead_strip` and `--icf=all`:

             base           diff           difference (95% CI)
  sys_time   0.935 ± 0.013  0.957 ± 0.018  [  +1.5% ..   +3.2%]
  user_time  3.472 ± 0.022  6.531 ± 0.046  [ +87.6% ..  +88.7%]
  wall_time  4.080 ± 0.040  5.329 ± 0.060  [ +30.0% ..  +31.2%]
  samples    37             30

Unsurprisingly, ICF is now a lot slower, likely due to the much larger
number of input sections it needs to process. But the rest of the
linker only suffers a mild slowdown.

Note that the compact-unwind-bad-reloc.s test was expanded because we
now handle the relocation for CUE's function address in a separate code
path from the rest of the CUE relocations. The extended test covers both
code paths.

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D109946
2021-11-12 16:02:49 -05:00
Jez Ng ad8df21db2 [reland][lld-macho] Fix symbol relocs handling for compact unwind's functionAddress
Clang seems to emit all functionAddress relocs as section relocs, but
`ld -r` can turn those relocs into symbol ones. It turns out that we
weren't handling that case correctly when the symbol was a weak def
whose definition did not prevail.

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D113702
2021-11-12 15:01:51 -05:00
Keith Smiley eb6f9f3123 [lld-macho] Fix trailing slash in oso_prefix
Previously if you passed `-oso_prefix path/to/foo/` with a trailing
slash at the end, using `real_path` would remove that slash, but that
slash is necessary to make sure OSO prefix paths end up as valid
relative paths instead of starting with `/`.

Differential Revision: https://reviews.llvm.org/D113541
2021-11-12 11:29:08 -08:00
Fangrui Song a05384dc89 [ELF] Make --no-relax disable R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX GOT optimization
This brings back the original version of D81359.
I have found several use cases now.

* Unlike GNU ld, LLD's relocation processing is one pass. If we decide to
  optimize(relax) R_X86_64_{,REX_}GOTPCRELX, we will suppress GOT generation and
  cannot undo the decision later. Optimizing R_X86_64_REX_GOTPCRELX can usually
  make it easy to hit `relocation R_X86_64_REX_GOTPCRELX out of range` because
  the distance to GOT is usually shorter. Without --no-relax, the user has to
  recompile with `-Wa,-mrelax-relocations=no`.
* The option would help during my investigationg of the root cause of https://git.kernel.org/linus/09e43968db40c33a73e9ddbfd937f46d5c334924
* There is need for relaxation for AArch64 & RISC-V. Implementing this for
  x86-64 improves consistency with little target-specific cost (two-line
  X86_64.cpp change).

Reviewed By: alexander-shaposhnikov

Differential Revision: https://reviews.llvm.org/D113615
2021-11-12 09:47:31 -08:00
Kazu Hirata 835135a8ae Revert "[lld-macho] Fix symbol relocs handling for compact unwind's functionAddress"
This reverts commit e941fe5061.

The commit in question causes:

  lld/MachO/InputFiles.cpp:916:13: error: use of undeclared identifier
  'it'
2021-11-11 20:29:48 -08:00
Jez Ng e941fe5061 [lld-macho] Fix symbol relocs handling for compact unwind's functionAddress
Clang seems to emit all functionAddress relocs as section relocs, but
`ld -r` can turn those relocs into symbol ones. It turns out that we
weren't handling that case correctly when the symbol was a weak def
whose definition did not prevail.

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D113702
2021-11-11 22:53:35 -05:00
Petr Hosek d56b171ee9 [lld][ELF] Support for R_ARM_THM_JUMP8
This change implements support for R_ARM_THM_JUMP8 relocation in
addition to R_ARM_THM_JUMP11 which is already supported by LLD.

Differential Revision: https://reviews.llvm.org/D21225
2021-11-11 09:06:52 -08:00
Igor Kudrin d2dd36bbbe [ELF] Better resemble GNU ld when placing orphan sections into memory regions
An orphan section should be placed in the same memory region as its
anchor section if the latter specifies the memory region explicitly.
If there is no explicit assignment for the anchor section in the linker
script, its memory region is selected by matching attributes, and the
same should be done for the orphan section.

Before the patch, some scripts that were handled smoothly in GNU ld
caused an "error: no memory region specified for section" in lld.

Differential Revision: https://reviews.llvm.org/D112925
2021-11-11 15:07:38 +07:00
Jez Ng a2404f11c7 [lld-macho] Support renaming of LSDA section
Previously, our unwind info finalization logic assumed that the LSDA
section referenced by `__compact_unwind` was already finalized before
`__TEXT,__unwind_info` itself. However, that assumption could be broken
by the use of `-rename_section` -- it could be (and is) used to move
`__gcc_except_tab` it into a different segment later in the file.
(__TEXT is always the first non-zerofill segment, so any rename
basically guarantees that the section will be ordered after
`__unwind_info`.)

To handle this case, we compare LSDA relocations instead of their final
values in `UnwindInfoSection::finalize()`, and we actually relocate
those LSDAs in `UnwindInfoSection::writeTo()`. In order to do this, we
need an easy way to track which Symbol a given CUE corresponds to. My
solution was to change our `cuPtrVector` into a vector of indices, with
each index used for both the symbols vector (`symbolsVec`) as well as
the CUE vector (`cuVector`).

This change seems perf neutral. Numbers for linking chromium_framework
on my 16 core Mac Pro:

             base           diff           difference (95% CI)
  sys_time   1.248 ± 0.025  1.245 ± 0.026  [  -1.3% ..   +0.8%]
  user_time  3.588 ± 0.045  3.587 ± 0.037  [  -0.6% ..   +0.5%]
  wall_time  4.605 ± 0.069  4.595 ± 0.069  [  -1.0% ..   +0.5%]
  samples    42             26

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D113582
2021-11-10 19:31:54 -05:00
Fangrui Song 51ee08c217 [ELF] Enforce double-dash form for --ignore-{data,function}-pointer-equality --reproduce --thread
They are LLD-specific options. We have enforced double-dash forms for
other options (reduce collision with short options) but missed them.
2021-11-10 01:17:08 -08:00
Fangrui Song d71bb6a409 [ELF] Inline isPPC64SmallCodeModelTocReloc which is only called once. NFC 2021-11-09 20:41:05 -08:00
Fangrui Song bec28ee1ea [ELF] Move isStaticLinkTimeConstant closer to the only caller processRelocAux. NFC 2021-11-09 20:37:46 -08:00
Fangrui Song 213d1849a4 [ELF] Improve sh_info=0 and sh_info>=num_sections diagnostic for SHT_REL/SHT_RELA
PR52408 reported an sh_info=0 instance. I have seen sh_info=0
independently before.

sh_info>=num_sections is probably very rare. Just use one diagnostic for
the two types of errors.

Delete invalid-relocations.test which is covered by invalid/bad-reloc-target.test

Differential Revision: https://reviews.llvm.org/D113466
2021-11-09 09:54:12 -08:00
Vy Nguyen 2e1be96df6 Reland "[lld-macho] Fix assertion failure in registerCompactUnwind""
PR/52372

  Differential Revision: https://reviews.llvm.org/D112977

New changes:
- use llvm-otool instead of `otool` which doesn't in exist on non-OSX platforms
- add llvm-otool to the set of tools used by test so that the bot will use the <build_dir>/bin/llvm-otool instead of the unqualified `llvm-otool` (which may not exist)
- update tests since the latest (TOT) llvm-otool prints a space between two bytes and the old one doesn't.
2021-11-09 11:52:46 -05:00
Vy Nguyen eb4a517816 Revert "[lld-macho] Fix assertion failure in registerCompactUnwind"
broke windows build - reverting to investigate
This reverts commit b2d9258474.
2021-11-09 10:31:47 -05:00
Vy Nguyen b2d9258474 [lld-macho] Fix assertion failure in registerCompactUnwind
PR/52372

  Differential Revision: https://reviews.llvm.org/D112977
2021-11-09 10:08:17 -05:00
Fangrui Song 43bb5f0185 [docs] Remove outdated documentation for the legacy Atom-based LLD
The outdated documentation diverges a lot from the current state of
COFF/Mach-O/ELF/wasm ports and may just confuse users. It is better rewriting
some if useful.

Tested with `ninja docs-lld-html`

Reviewed By: #lld-macho, lhames, Jez Ng

Differential Revision: https://reviews.llvm.org/D113432
2021-11-08 15:20:16 -08:00
Fangrui Song cebb0a64b4 [ELF][ARM] Improve error message for unknown relocation
Like rLLD354040.

Before: `error: unrecognized relocation Unknown (254)`
Now:    `error: unknown relocation (254) against symbol foo`
2021-11-08 12:39:08 -08:00
David Blaikie 78758026e2 Fix lld test after dwarfdump array syntax change 2021-11-05 23:00:29 -07:00
Fangrui Song 26a8ceba3e [llvm-readobj] Display DT_RELRSZ/DT_RELRENT as " (bytes)"
to match RELSZ/RELENT.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D113206
2021-11-05 10:02:49 -07:00
Quinn Pham c71fbdd87b [NFC] Inclusive language: Remove instances of master in URLs
[NFC] This patch fixes URLs containing "master". Old URLs were either broken or
redirecting to the new URL.

Reviewed By: #libc, ldionne, mehdi_amini

Differential Revision: https://reviews.llvm.org/D113186
2021-11-05 08:48:41 -05:00
Keith Smiley a7a2959901 [lld-macho] Replace LC_LINKER_OPTION parsing
This removes the tablegen based parsing of LC_LINKER_OPTION since it can
only actually contain a very small number of potential arguments. In our
project with tablegen this took 5 seconds before.

This replaces https://reviews.llvm.org/D113075

Differential Revision: https://reviews.llvm.org/D113235
2021-11-04 22:03:40 -07:00
Fangrui Song 005456e5fc [lld-macho] Fix an assertion failure when -u specifies an undefined section$start symbol
This matches ld64. Also improve the test for `-dead_strip`.

Reviewed By: #lld-macho, Jez Ng

Differential Revision: https://reviews.llvm.org/D113147
2021-11-04 21:28:33 -07:00
Keith Smiley 0bce3e3b84 [lld-macho] Clear resolvedReads cache
https://reviews.llvm.org/D113153#3108083

smeenai, int3

Differential Revision: https://reviews.llvm.org/D113198
2021-11-04 18:02:34 -07:00
Noah Shutty d788c44f5c [Support] Improve Caching conformance with Support library behavior
This diff makes several amendments to the local file caching mechanism
which was migrated from ThinLTO to Support in
rGe678c51177102845c93529d457b020f969125373 in response to follow-up
discussion on that commit.

Patch By: noajshu

Differential Revision: https://reviews.llvm.org/D113080
2021-11-04 13:00:44 -07:00
Keith Smiley e7fdff403e [lld-macho] Silently ignore the -objc_abi_version
This undocumented ld64 flag, based on the most recent ld64 source dump
from Xcode 12, only applies to i386. It seems like on all newer
architectures this behavior is the default.

Reviewed By: #lld-macho, int3

Differential Revision: https://reviews.llvm.org/D113070
2021-11-03 22:16:09 -07:00
Keith Smiley d49e7244cc [lld-macho] Cache readFile results
In one of our links lld was reading 760k files, but the unique number of
files was only 1500. This takes that link from 30 seconds to 8.

This seems like a heavy hammer, especially since some things don't need
to be cached, like the filelist arguments and the passed static
archives (the latter is already cached as a one off), but it seems ld64
does something similar here to short circuit these duplicate reads:

82e429e186/src/ld/InputFiles.cpp (L644-L665)

Of the types of files being read for our iOS app, the biggest problem
was constantly re-reading small tbd files:

```
% wc -l /tmp/read.txt
761414 /tmp/read.txt
% cat /tmp/read.txt | sort -u | wc -l
1503

% cat /tmp/read.txt | grep "\.a$" | wc -l
43721
% cat /tmp/read.txt | grep "\.tbd$" | wc -l
717656
```

We could likely hoist this logic up to not cache at this level, but it
would be a more invasive change to make sure all callers that needed it
cached the results.

I could see this being an issue with OOMs, and I'm not a linker expert so
maybe there's another way we should solve this problem? Feedback welcome!

Reviewed By: int3, #lld-macho

Differential Revision: https://reviews.llvm.org/D113153
2021-11-03 22:12:21 -07:00
Keith Smiley 6629ec3ecc [lld-macho] Implement -arch_errors_fatal
By default with ld64, architecture mismatches are just warnings, then
this flag can be passed to make these fail. This matches that behavior.

Reviewed By: int3, #lld-macho

Differential Revision: https://reviews.llvm.org/D113082
2021-11-03 22:01:53 -07:00
Jez Ng 4ae8c83104 [lld-macho][nfc] Remove unnecessary -pie flags in tests
D101513 means that we no longer need to specify `-pie` in most of our
test RUN commands. Let's clean up the unused flags so as not to confuse
future test writers.

Reviewed By: #lld-macho, oontvoo, MaskRay

Differential Revision: https://reviews.llvm.org/D113114
2021-11-04 00:02:03 -04:00
Keith Smiley 4313c56aa3 [lld-macho] Enable search-paths tests on macOS
I'm not sure what the history is here but this test passes on macOS
today. It seems like we should unify these tests if they need to run
cross platform.

Reviewed By: #lld-macho, int3

Differential Revision: https://reviews.llvm.org/D113085
2021-11-03 12:01:36 -07:00
Keith Smiley 63e65de3ff [lld-macho] Cache discovered framework paths
On our large iOS project this took a link from 1 minute 45 seconds to 45
seconds. For reference ld64 does the same link in ~20 seconds.

Reviewed By: #lld-macho, int3

Differential Revision: https://reviews.llvm.org/D113063
2021-11-03 11:11:54 -07:00
Keith Smiley f79e65e61f [lld-macho] Cache library paths from findLibrary
On top of https://reviews.llvm.org/D113063 this took another 10 seconds
off our overall link time.

Reviewed By: #lld-macho, int3

Differential Revision: https://reviews.llvm.org/D113073
2021-11-03 10:02:23 -07:00
Fangrui Song c977564fc2 Revert "[ELF] Try appeasing --target=armv7-linux-androideabi24 sanitizer symbolization tests"
This reverts commit 5cbec88cbf.

Vitaly said that 2faac77f26 actually works.

Sanitizer's armv7-linux-androideabi24 configuration has other issues which haven't been identified yet, but that's unrelated to the empty symbol name issue.
2021-11-03 00:56:09 -07:00
Fangrui Song 5cbec88cbf [ELF] Try appeasing --target=armv7-linux-androideabi24 sanitizer symbolization tests 2021-11-02 18:57:04 -07:00
Vy Nguyen 37f96cb478 Revert "[lld-macho] Change bitfield types to be identical."
This reverts commit ae31f9fbad.

Reason: bitfields can't be merged across parent/child classes anyway. So this change doesn't help.
2021-11-02 16:57:51 -04:00
Vy Nguyen ae31f9fbad [lld-macho] Change bitfield types to be identical.
Symbol's subclasses all have an additional bitfield of type uint8_t (RefState enum).
For the bitfields in the same block tomerge, they should be of the same type. (clang/gcc will work, but others like MSVC does not)

Differential Revision: https://reviews.llvm.org/D113040
2021-11-02 15:48:39 -04:00
Nico Weber 64c1734438 [lld/mac] Write -v output to stderr
This matches ld64, and it's conceivable that projects try to read
this information off stderr for that reason.

--version keeps writing to stdout.

Differential Revision: https://reviews.llvm.org/D113020
2021-11-02 13:59:14 -04:00
Vy Nguyen d7e5393af4 [lld-macho] Remove no_dtrace_dof from un-implemented group.
One fewer warning.
In practice, lld already "implements" it. (ie., it does not do dtrace-dof processing ever).

Reviewed By: #lld-macho, thakis

Differential Revision: https://reviews.llvm.org/D112934
2021-11-02 12:36:08 -04:00
Vy Nguyen 3f35dd06a5 [lld-macho][nfc][cleanup] Fix a few code style lints and clang-tidy findings
- Use .empty() instead of `size() == 0` when possible.
- Use const-ref to avoid copying

Differential Revision: https://reviews.llvm.org/D112978
2021-11-02 11:26:15 -04:00
Shoaib Meenai 7a4b27609d [lld] Add test suite mode for running LLD main twice
LLD_IN_TEST determines how many times each port's `main` function is
run in each LLD process, and setting LLD_IN_TEST=2 (or higher) is useful
for checking if we're cleaning up and resetting global state correctly.
Add a test suite parameter to enable this easily. There's work in
progress to remove global state (e.g. D108850), but this seems useful in
the interim.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D112898
2021-11-01 14:26:54 -07:00
Fangrui Song 2f7366c89d [ELF] Simplify R_DTPREL. NFC 2021-10-31 20:30:00 -07:00