Commit Graph

3578 Commits

Author SHA1 Message Date
Georgii Rymar dac5ddb482 [llvm-readelf/llvm-readobj] - Improved the error reporting in a few method related to versioning.
I was investigating a change previously discussed that eliminates an excessive
empty lines from the output when we report warnings and errors
(https://reviews.llvm.org/D70826#inline-639055) and found
that we need this refactoring or alike to achieve that.

The problem is that some of our functions that finds symbol versions just
fail instead of returning errors or printing warnings. Another problem
is that they might print a warning on the same line with the regular output.
In this patch I've splitted getting of the version information and dumping of it
for GNU printVersionSymbolSection(). I had to change a few methods to return
Error or Expected<> to do that properly.

Differential revision: https://reviews.llvm.org/D71118
2019-12-10 13:08:18 +03:00
Hans Wennborg bfb53c55b8 Add more diff -b to roundtrip-compress.test
It was missing on the first test invocation. The flag is necessary to
ignore line-ending differences on Windows.
2019-12-10 10:32:16 +01:00
Georgii Rymar dbf520f617 [llvm-readobj][test] - Move platform specific test cases and their inputs to separate folders.
This creates the next subfolders in the test directory:
"COFF", "ELF", "MachO", "wasm".

I've also removed platform specific prefixes, like "coff-*".
One unused binary was removed as well: `Inputs/relocs.obj.elf-mips`

Differential revision: https://reviews.llvm.org/D71203
2019-12-10 11:36:23 +03:00
Jonas Devlieghere d9466653e4 [llvm/dwarfdump] Use the architecture string to filter.
Currently dwarfdump uses the ArchType to filter out architectures, which
is problematic for architectures like arm64e and x86_64h that map back
to arm64 and x86_64 respectively. The result is that the filter doesn't
work for these architectures because it matches all the variants. This
is especially bad because usually these architectures are the reason to
use the filter in the first place.

Instead, we should match the architecture based on the string name. This
means the filter works for the values printed by dwarfdump. It has the
unfortunate side effect of not working for aliases, like AArch64, but I
think that's worth the trade-off.

rdar://53653014

Differential revision: https://reviews.llvm.org/D71230
2019-12-09 17:17:01 -08:00
James Henderson 01d8bb4939 [test][llvm-cxxfilt] Add missing '-n'
See also e84468c1f.
2019-12-09 15:06:41 +00:00
James Henderson 2815390532 [test][llvm-cxxfilt] Fix darwin build bot
When committing dba420bc05, I missed that a darwin-specific change had
been recently introduced into llvm-cxxfilt, which my change ignored and
consequently broke the darwin build bot. This change fixes this issue as
well as improving naming/commenting of things related to this point so
that people are less likely to run into the same issue as I did.
2019-12-09 14:01:14 +00:00
Jeremy Morse 00e238896c [DebugInfo] Nerf placeDbgValues, with prejudice
CodeGenPrepare::placeDebugValues moves variable location intrinsics to be
immediately after the Value they refer to. This makes tracking of locations
very easy; but it changes the order in which assignments appear to the
debugger, from the source programs order to the order in which the
optimised program computes values. This then leads to PR43986 and PR38754,
where variable locations that were in a conditional block are made
unconditional, which is highly misleading.

This patch adjusts placeDbgValues to only re-order variable location
intrinsics if they use a Value before it is defined, significantly reducing
the damage that it does. This is still not 100% safe, but the rest of
CodeGenPrepare needs polishing to correctly update debug info when
optimisations are performed to fully fix this.

This will probably break downstream debuginfo tests -- if the
instruction-stream position of variable location changes isn't the focus of
the test, an easy fix should be to manually apply placeDbgValues' behaviour
to the failing tests, moving dbg.value intrinsics next to SSA variable
definitions thus:

  %foo = inst1
  %bar = ...
  %baz = ...
  void call @llvm.dbg.value(metadata i32 %foo, ...

to

  %foo = inst1
  void call @llvm.dbg.value(metadata i32 %foo, ...
  %bar = ...
  %baz = ...

This should return your test to exercising whatever it was testing before.

Differential Revision: https://reviews.llvm.org/D58453
2019-12-09 12:52:10 +00:00
James Henderson dba420bc05 [test][tools] Add missing and improve testing
Mostly this adds testing for certain aliases in more explicit ways.
There are also a few tidy-ups, and additions of missing testing, where
the feature was either not tested at all, or not tested explicitly and
sufficiently.

Reviewed by: MaskRay, rupprecht, grimar

Differential Revision: https://reviews.llvm.org/D71116
2019-12-09 12:24:23 +00:00
Kristina Bessonova 68f464ac2e [llvm-dwarfdump][Statistics] Unify coverage statistic computation
Summary:
The patch removes OffsetToFirstDefinition in the 'scope bytes total'
statistic computation. Thus it unifies the way the scope and the coverage
buckets are computed. The rationals behind that are the following:

1. OffsetToFirstDefinition was used to calculate the variable's life range.
However, there is no simple way to do it accurately, so the scope calculated
this way might be misleading. See D69027 for more details on the subject.
2. Both 'scope bytes total' and coverage buckets seem to be intended
to represent the same data in different ways. Otherwise, the statistics
might be controversial and confusing.

Note that the approach gives up a thorough evaluation of debug information
completeness (i.e. coverage buckets by themselves doesn't tell how good
the debug information is). Only changes in coverage over time make
a 'physical' sense.

Reviewers: djtodoro, aprantl, vsk, dblaikie, avl

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70548
2019-12-08 15:46:49 +03:00
Georgii Rymar 18cf93a6ed [llvm-readobj][llvm-readelf] - Refactor parsing of the SHT_GNU_versym section.
This introduce a new helper which is used to parse the SHT_GNU_versym section.
LLVM/GNU styles implementations now use it to share the logic.

Differential revision: https://reviews.llvm.org/D71054
2019-12-06 15:35:05 +03:00
Georgii Rymar cd2c409ceb [llvm-readobj] - Implement --dependent-libraries flag.
There is no way to dump SHT_LLVM_DEPENDENT_LIBRARIES sections
currently. This patch implements this.

The section is described here:
https://llvm.org/docs/Extensions.html#sht-llvm-dependent-libraries-section-dependent-libraries

Differential revision: https://reviews.llvm.org/D70665
2019-12-06 14:28:29 +03:00
Amy Huang 23e63a906d Use diff -b on zlib tests so they pass on Windows
Reviewers: hubert.reinterpretcast

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71036
2019-12-05 11:32:58 -08:00
Puyan Lotfi ef7267def6 [llvm] llvm-ifs: Support for handling empty IFS and merging weak+strong symbols.
The following changes enable llvm-ifs to handle the following merge conflicts:

* Weak + Strong symbol merging for the same symbol
* empty vs non-empty triple field
* empty vs non-empty object file format

Differential Revision: https://reviews.llvm.org/D70834
2019-12-05 12:56:37 -05:00
Pavel Labath 4ee76a922a [llvm/DWARF] Return section offset from DWARFUnit::get{Loc,Rng}listOffset
Summary:
Currently these function return the raw content of the appropriate table
header, which means they are relative to the DW_AT_{loc,rng}list_base,
and one has to relocate them in order to do anything.

This changes the functions to perform the relocation themselves, which
seems more clearer, particularly as they are sitting right next to the
find{Rng,Loc}listFromOffset functions, but one *cannot* simply take the
result of these functions and take pass them there.

The only effect of this patch is to change what value is dumped for the
DW_AT_ranges attribute, which I think is for the better, as previously
the values appeared to point into thin air.

(The main reason I am looking at this is because I was trying to
implement equivalent functionality in lldb's DWARFUnit, and was stumped
by this behavior.

Reviewers: dblaikie, JDevlieghere, aprantl

Subscribers: hiraditya, llvm-commits, SouraVX

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71006
2019-12-05 12:35:09 +01:00
Xiangling Liao 8b8a7d1ecf Revert "Add --strip-trailing-cr to compression tests so they pass on Windows."
This reverts commit d6cbc9528d.

It causes the tests to fail on AIX.
2019-12-04 17:26:30 -05:00
Amy Huang d6cbc9528d Add --strip-trailing-cr to compression tests so they pass on Windows. 2019-12-04 13:23:27 -08:00
Vedant Kumar f208b70fbc Revert "[Coverage] Revise format to reduce binary size"
This reverts commit e18531595b.

On Windows, there is an error:

http://lab.llvm.org:8011/builders/sanitizer-windows/builds/54963/steps/stage%201%20check/logs/stdio

error: C:\b\slave\sanitizer-windows\build\stage1\projects\compiler-rt\test\profile\Profile-x86_64\Output\instrprof-merging.cpp.tmp.v1.o: Failed to load coverage: Malformed coverage data
2019-12-04 10:35:14 -08:00
Vedant Kumar e18531595b [Coverage] Revise format to reduce binary size
Revise the coverage mapping format to reduce binary size by:

1. Naming function records and marking them `linkonce_odr`, and
2. Compressing filenames.

This shrinks the size of llc's coverage segment by 82% (334MB -> 62MB)
and speeds up end-to-end single-threaded report generation by 10%. For
reference the compressed name data in llc is 81MB (__llvm_prf_names).

Rationale for changes to the format:

- With the current format, most coverage function records are discarded.
  E.g., more than 97% of the records in llc are *duplicate* placeholders
  for functions visible-but-not-used in TUs. Placeholders *are* used to
  show under-covered functions, but duplicate placeholders waste space.

- We reached general consensus about giving (1) a try at the 2017 code
  coverage BoF [1]. The thinking was that using `linkonce_odr` to merge
  duplicates is simpler than alternatives like teaching build systems
  about a coverage-aware database/module/etc on the side.

- Revising the format is expensive due to the backwards compatibility
  requirement, so we might as well compress filenames while we're at it.
  This shrinks the encoded filenames in llc by 86% (12MB -> 1.6MB).

See CoverageMappingFormat.rst for the details on what exactly has
changed.

Fixes PR34533 [2], hopefully.

[1] http://lists.llvm.org/pipermail/llvm-dev/2017-October/118428.html
[2] https://bugs.llvm.org/show_bug.cgi?id=34533

Differential Revision: https://reviews.llvm.org/D69471
2019-12-04 10:10:55 -08:00
Troy Johnson a6febd53c9 [Gold Tests] Add missing target flag to X86 test
This test was failing on non-X86 targets because the gold invocation did not
have the necessary -m flag.

Differential Revision: https://reviews.llvm.org/D70982
2019-12-04 11:50:44 -06:00
gbreynoo 8c1e1d1482 [llvm-ar][test] Add to thin archive test coverage
This diff adds test coverage for thin archives including additions to
existing tests. In some cases I have updated the formats of these tests
to better match other tests in the archive.

Differential Revision: https://reviews.llvm.org/D70969
2019-12-04 16:17:42 +00:00
Peter Smith 2120612e46 [ELF] Support for PT_GNU_PROPERTY in header and tools
The PT_GNU_PROPERTY is generated by a linker to describe the
.note.gnu.property section. The Linux kernel uses this program header to
locate the .note.gnu.property section.

It is described in "The Linux gABI extension"

Include support for llvm-readelf, llvm-readobj and the yaml reader and
writers.

Differential Revision: https://reviews.llvm.org/D70959
2019-12-04 15:38:12 +00:00
Georgii Rymar daff7b8589 [yaml2obj] - Make DynamicSymbols to be Optional<> too.
We already have Symbols property to list regular symbols and
it is currently Optional<>. This patch makes DynamicSymbols to be optional
too. With this there is no need to define a dummy symbol anymore to trigger
creation of the .dynsym and it is now possible to define an empty .dynsym using
just the following line:

DynamicSymbols: []
(it is important to have when you do not want to have dynamic symbols,
but want to have a .dynsym)

Now the code is consistent and it helped to fix a bug: previously we
did not report an error when both Content/Size and an empty
Symbols/DynamicSymbols list were specified.

Differential revision: https://reviews.llvm.org/D70956
2019-12-04 13:12:02 +03:00
Pavel Labath a3af3ac393 [DWARFDebugLoclists] Add support for other DW_LLE encodings
Summary:
lldb's loclists parser has support for DW_LLE_start_end(x) encodings. To
avoid regressing when switching the implementation to llvm's, I add
parsing support for all previously unsupported location list encodings.

Reviewers: dblaikie, JDevlieghere, aprantl, SouraVX

Subscribers: hiraditya, probinson, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70949
2019-12-04 10:38:21 +01:00
Georgii Rymar 3b47e6efb9 [yaml2obj][test] - Remove excessive symtab-shinfo.yaml.
The same testing is performed in `implicit-sections-info.yaml`:
https://github.com/llvm-mirror/llvm/blob/master/test/tools/yaml2obj/implicit-sections-info.yaml

Differential revision: https://reviews.llvm.org/D70957
2019-12-04 12:01:39 +03:00
Fangrui Song 36663d506e [llvm-strip][MachO] Test llvm-strip --strip-debug
Reviewed By: smeenai

Differential Revision: https://reviews.llvm.org/D70995
2019-12-03 21:15:56 -08:00
Georgii Rymar d7ecc0256e [Object/ELF] - Refine the error reported when section's offset + size overruns the file buffer.
This is a follow-up requested in comments for D70826.

It changes the message from
"section X has a sh_offset (Y) + sh_size (Z) that cannot be represented"
to
"section X has a sh_offset (Y) + sh_size (Z) that is greater than the file size (0xABC)"

when section's sh_offset + sh_size overruns a file buffer.

Differential revision: https://reviews.llvm.org/D70893
2019-12-03 17:55:55 +03:00
Pavel Labath 1fbe8a82e1 [DWARF] Add support for parsing/dumping section indices in location lists
Summary:
This does exactly what it says on the box. The only small gotcha is the
section index computation for offset_pair entries, which can use either
the base address section, or the section from the offset_pair entry.
This is to support both the cases where the base address is relocated
(points to the base of the CU, typically), and the case where the base
address is a constant (typically zero) and relocations are on the
offsets themselves.

Reviewers: dblaikie, JDevlieghere, aprantl, SouraVX

Subscribers: hiraditya, llvm-commits, probinson

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70540
2019-12-03 11:48:28 +01:00
Wang, Pengfei cf81714a7e [X86] Model MXCSR for AVX instructions other than AVX512
Summary: Model MXCSR for AVX instructions other than AVX512

Reviewers: craig.topper, RKSimon

Subscribers: hiraditya, llvm-commits, LuoYuanke, LiuChen3

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70875
2019-12-03 08:53:47 +08:00
Clement Courbet 3540b80fe4 [llvm-exegesis] Fix 44b9942898.
Summary:
Add missing stack release instructions in
loadImplicitRegAndFinalize.

Reviewers: pengfei, gchatelet

Subscribers: tschuett, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70903
2019-12-02 16:13:27 +01:00
Wang, Pengfei 76b70f6f75 [X86] Add initialization of FPCW in llvm-exegesis
Summary: This is a following up to D70874. It adds the initialization of FPCW in llvm-exegesis.

Reviewers: craig.topper, RKSimon, courbet, gchatelet

Subscribers: tschuett, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70891
2019-12-02 20:18:35 +08:00
Georgii Rymar e19f19b09f [llvm-readobj/llvm-readelf] - Simplify the code that dumps versions.
After changes introduced in D70495 and D70826 its now possible
to significantly simplify the code we have.

This also fixes an issue: previous code assumed that version strings
should always be read from the dynamic string table. While it is
normally true, the string table should be taken from the corresponding
sh_link field.

Differential revision: https://reviews.llvm.org/D70855
2019-12-02 15:14:30 +03:00
Wang, Pengfei 44b9942898 [X86] Add initialization of MXCSR in llvm-exegesis
Summary: This patch is used to initialize the new added register MXCSR.

Reviewers: craig.topper, RKSimon

Subscribers: tschuett, courbet, llvm-commits, LiuChen3

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70874
2019-12-02 18:19:32 +08:00
Georgii Rymar 7eecf2b872 [llvm-readelf/llvm-readobj] - Check the version of SHT_GNU_verneed section entries.
It is a follow-up for D70826 and it is similar to D70810.

SHT_GNU_verneed contains the following fields:
`vn_version`: Version of structure. This value is currently set to 1, and will be reset
if the versioning implementation is incompatibly altered.
(https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/symversion.html)

We should check it for correctness.

Differential revision: https://reviews.llvm.org/D70842
2019-12-02 12:57:23 +03:00
Georgii Rymar c653a52c85 [llvm-readobj/llvm-readelf] - Reimplement dumping of the SHT_GNU_verneed section.
This is similar to D70495, but for SHT_GNU_verneed section.
It solves the same problems: different implementations, lack of error reporting
and no test coverage.

DIfferential revision: https://reviews.llvm.org/D70826
2019-12-02 12:27:31 +03:00
Georgii Rymar 99adf047c8 [llvm-readelf][test] - Update comment in elf-verdef-invalid.test. NFC.
It was suggested to change it during review of D70810,
but I've forgotten to update it before commit.
2019-11-29 11:38:27 +03:00
Georgii Rymar 7ab1481361 [llvm-readelf/llvm-readobj] - Check version of SHT_GNU_verdef section entries when dumping.
Elfxx_Verdef contains the following field:

vd_version
Version revision. This field shall be set to 1.
(https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/symversion.html)

Our code should check the struct version for correctness. This patch does that.
(This will help to simplify or eliminate ELFDumper<ELFT>::LoadVersionDefs() which
has it's own logic to parse version definitions for no reason. It checks the
struct version currently).

Differential revision: https://reviews.llvm.org/D70810
2019-11-29 11:09:56 +03:00
Georgii Rymar 13cbcf1c1a [yaml2obj] - Add a way to describe content of the SHT_GNU_verneed section with "Content".
There is no way to set raw content for SHT_GNU_verneed section.
This patch implements it.

Differential revision: https://reviews.llvm.org/D70816
2019-11-29 10:50:00 +03:00
Georgii Rymar 7f362f04a7 [llvm-readelf] - Make GNU style dumping of invalid SHT_GNU_verdef be consistent with LLVM style.
When we dump SHT_GNU_verdef section that has sh_link that references a non-existent section,
llvm-readobj reports a warning and continues dump, but llvm-readelf fails with a error.

This patch fixes the issue and opens road for futher follow-ups for
improving the printGNUVersionSectionProlog().

Differential revision: https://reviews.llvm.org/D70776
2019-11-28 12:41:29 +03:00
Georgii Rymar bb7d75ef1d [llvm-readelf][llvm-readobj][test] - Cleanup test cases for versioning sections.
Currently we have 2 tests for testing versioning sections:
1) elf-versioninfo.test
2) elf-invalid-versioning.test

The first one currently checks how versioning sections are dumped +
how tools dump invalid SHT_GNU_verdef section.

The second despite of its name contains only tests for invalid SHT_GNU_verneed section.

In this patch I`ve renamed elf-invalid-versioning.test->elf-verneed-invalid.test,
and moved a few tests from elf-versioninfo.test to a new elf-verdef-invalid.test.

It will help to maintain these and a new tests for broken versioning sections.

Differential revision:
2019-11-28 10:18:51 +03:00
Georgii Rymar 3b35603a56 [llvm-readobj] - Always print "Predecessors" for version definition sections.
This is a follow-up discussed in D70495 thread.

The current logic is unusual for llvm-readobj. It doesn't print predecessors
list when it is empty. This is not good for machine parsers.
D70495 had to add this condition during refactoring to reduce amount of changes,
in tests, because the original code also had a similar logic.

Now seems it is time to get rid of it. This patch does it.

Differential revision: https://reviews.llvm.org/D70717
2019-11-27 12:29:55 +03:00
Georgii Rymar d88f67bdca [llvm-readobj/llvm-readelf] - Reimplement dumping of the SHT_GNU_verdef section.
Currently we have following issues:
1) We have 2 different implementations with a different behaviors for GNU/LLVM styles.
2) Errors are either not handled at all or we call report_fatal_error with not helpfull messages.
3) There is no test coverage even for those errors that are reported.

This patch reimplements parsing of the SHT_GNU_verdef section entries
in a single place, adds a few error messages and test coverage.

Differential revision: https://reviews.llvm.org/D70495
2019-11-26 17:15:39 +03:00
Georgii Rymar 64225aea8f [llvm-readobj][test] - Cleanup the many-sections.s test case.
It removes 2 precompiled binaries used which are now
can be crafted with the use of yaml2obj.

Differential revision: https://reviews.llvm.org/D70711
2019-11-26 16:56:48 +03:00
Georgii Rymar 91827ebf5e [yaml2obj] - Fix BB after «[yaml2obj] - Teach tool to describe SHT_GNU_verdef section with a "Content" property.»
Fixed a temporary file name.

BB: http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-ubuntu/builds/669
2019-11-26 16:05:38 +03:00
Georgii Rymar f69ac55d60 [yaml2obj] - Teach tool to describe SHT_GNU_verdef section with a "Content" property.
There is no way to set raw content for SHT_GNU_verdef section.
This patch implements it.

Differential revision: https://reviews.llvm.org/D70710
2019-11-26 15:35:05 +03:00
Evgenii Stepanov 06d1110584 Speculative fix for frame-loclist.s test on Windows.
"echo -e" treats windows paths as special characters (ex. "\b").
2019-11-25 17:51:15 -08:00
Evgenii Stepanov 5906fb682d Fix new llvm-symbolizer tests on Windows.
A forward-slash vs backward-slash issue.
2019-11-25 15:59:13 -08:00
Evgenii Stepanov 1b42cc0df1 llvm-symbolizer: fix handling of DW_AT_specification in FRAME.
Summary:
Use getSubroutineName() to the the subrouting name; this function knows
how to handle cases when DW_TAG_subprogram refers to an earlier
declaration:

0x00000050:     DW_TAG_subprogram
                  DW_AT_linkage_name    ("_ZN1A1fEv")
                  DW_AT_name    ("f")
...
0x00000067:   DW_TAG_subprogram
                DW_AT_low_pc    (0x0000000000000000)
                DW_AT_high_pc   (0x0000000000000020)
                DW_AT_specification     (0x00000050 "_ZN1A1fEv")
...
0x0000008c:     DW_TAG_variable

Reviewers: pcc, vitalybuka, jdoerfert

Subscribers: srhines, hiraditya, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70630
2019-11-25 15:06:07 -08:00
Evgenii Stepanov 9f60820d84 llvm-symbolizer: Support loclist in FRAME.
Summary:
Support location lists in FRAME command.
These are used for the majority of local variables in optimized code.
Also support DW_OP_breg in addition to DW_OP_fbreg when it refers to the
same register as DW_AT_frame_base.

Reviewers: pcc, jdoerfert

Subscribers: srhines, hiraditya, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70629
2019-11-25 15:06:07 -08:00
Evgenii Stepanov 1c33d7130e llvm-symbolizer: Fix FRAME handling of missing AT_name.
Summary:
llvm-symbolizer protocol is empty string means end-of-output.
Do not emit empty string when a function or a variable do not have a
name for any reason. Emit "??".

Reviewers: pcc, vitalybuka, jdoerfert

Subscribers: srhines, hiraditya, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70626
2019-11-25 14:55:11 -08:00
Georgii Rymar 9659464d7e [yaml2obj/obj2yaml] - Add support for SHT_LLVM_DEPENDENT_LIBRARIES sections.
This section contains strings specifying libraries to be added to the link by the linker.
The strings are encoded as standard null-terminated UTF-8 strings.

This patch adds a way to describe and dump SHT_LLVM_DEPENDENT_LIBRARIES sections.

I introduced a new YAMLFlowString type here. That used to teach obj2yaml to dump
them like:

```
Libraries: [ foo, bar ]
```

instead of the following (if StringRef would be used):

```
Libraries:
  - foo
  - bar
```

Differential revision: https://reviews.llvm.org/D70598
2019-11-25 12:57:53 +03:00