Commit Graph

105 Commits

Author SHA1 Message Date
Raphael Isemann 77440d644b [lldb][NFC] Allow range-based for loops over DWARFDIE's children
This patch adds the ability to get a DWARFDIE's children as an LLVM range.

This way we can use for range loops to iterate over them and we can use LLVM's
algorithms like `llvm::all_of` to query all children.

The implementation has to do some small shenanigans as the iterator needs to
store a DWARFDIE, but a DWARFDIE container is also a DWARFDIE so it can't return
the iterator by value. I just made the `children` getter a templated function to
avoid the cyclic dependency.

Reviewed By: #lldb, werat, JDevlieghere

Differential Revision: https://reviews.llvm.org/D103172
2021-07-22 15:03:30 +02:00
Raphael Isemann c462048cc4 [lldb][NFC] Use SubsystemRAII in XcodeSDKModuleTests 2021-06-22 13:41:01 +02:00
Med Ismail Bennani d5069dace7
[lldb/Symbol] Fix typo in SymbolFilePDBTests (NFC)
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-05-05 00:38:41 +00:00
Med Ismail Bennani 30fcdf0b19 [lldb/Symbol] Update SymbolFilePDB unitest with SourceLocationSpec
This patch should fix the windows test failure following `3e2ed7440569`.

It makes use of a `SourceLocationSpec` object  when resolving a symbol
context from `SymbolFilePDB` file.

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-05-05 00:34:44 +00:00
Pavel Labath 2ecf928153 [lldb/DWARF] Fix a crash parsing invalid dwarf (pr49678)
If the debug info is missing the terminating null die, we would crash
when trying to access the nonexisting children/siblings. This was
discovered because the test case for D98619 accidentaly produced such
input.
2021-04-08 16:48:02 +02:00
Pavel Labath 5978912da0 [lldb] Add a dwarf unit test for null unit dies
This is the test I mentioned in the previous commit (1b96e133), but
forgot to add.
2021-03-30 08:46:36 +02:00
Greg Clayton eee309068e Fix .debug_aranges parsing issues.
When LLVM error handling was introduced to the parsing of the .debug_aranges it would cause major issues if any DWARFDebugArangeSet::extract() calls returned any errors. The code in DWARFDebugInfo::GetCompileUnitAranges() would end up calling DWARFDebugAranges::extract() which would return an error if _any_ DWARFDebugArangeSet had any errors, but it default constructed a DWARFDebugAranges object into DWARFDebugInfo::m_cu_aranges_up and populated it partially, and returned an error prior to finishing much needed functionality in the DWARFDebugInfo::GetCompileUnitAranges() function. Subsequent callers to this function would see that the DWARFDebugInfo::m_cu_aranges_up was actually valid and return this partially populated DWARFDebugAranges reference _and_ it would not be sorted or minimized.

This above bugs would cause an incomplete .debug_aranges parsing, it would skip manually parsing any compile units for ranges, and would not sort the DWARFDebugAranges in m_cu_aranges_up.

This bug would also cause breakpoints set by file and line to fail to set correctly if a symbol context for an address could not be resolved properly, which the incomplete and unsorted DWARFDebugAranges object that DWARFDebugInfo::GetCompileUnitAranges() returned would cause symbol context lookups resolved by address (breakpoint address) to fail to find any DWARF debug info for a given address.

This patch fixes all of the issues that I found:
- DWARFDebugInfo::GetCompileUnitAranges() no longer returns a "llvm::Expected<DWARFDebugAranges &>", but just returns a "const DWARFDebugAranges &". Why? Because this code contained a fallback that would parse all of the valid DWARFDebugArangeSet objects, and would check which compile units had valid .debug_aranges set entries, and manually build an address ranges table using DWARFUnit::BuildAddressRangeTable(). If we return an error because any DWARFDebugArangeSet has any errors, then we don't do any of this code. Now we parse all DWARFDebugArangeSet objects that have no errors, if any calls to DWARFDebugArangeSet::extract() return errors, we skip that DWARFDebugArangeSet so that we can use the fallback call to DWARFUnit::BuildAddressRangeTable(). Since DWARFDebugInfo::GetCompileUnitAranges() needs to parse what it can from the .debug_aranges and build address ranges tables for any compile units that don't have any .debug_aranges sets, everything now works as expected.
- Fix an issue where a DWARFDebugArangeSet contains multiple terminator entries. The LLVM parser and llvm-dwarfdump properly warn about this because it happens with linux compilers and linkers and was the original cause of the bug I am fixing here. We now correctly warn about this issue if "log enable dwarf info" is enabled, but we continue to parse the DWARFDebugArangeSet correctly so we don't lose data that is contained in the .debug_aranges section.
- DWARFDebugAranges::extract() no longer returns a llvm::Error because we need to be able to parse all of the valid DWARFDebugArangeSet objects. It also will correctly skip a DWARFDebugArangeSet object that has errors in the middle of the stream by setting the start offsets of each DWARFDebugArangeSet to be calculated by the previous DWARFDebugArangeSet::extract() calculated offset that uses the header which contains the length of the DWARFDebugArangeSet. This means if do we run into real errors while parsing individual DWARFDebugArangeSet objects, we can continue to parse the rest of the validly encoded DWARFDebugArangeSet objects in the .debug_aranges section. This will allow LLDB to parse DWARF that contains a possibly newer .debug_aranges set format than LLDB currently supports because we will error out for the parsing of the DWARFDebugArangeSet, but be able to skip to the next DWARFDebugArangeSet object using the "DWARFDebugArangeSet.m_header.length" field to calculate the next starting offset.

Tests were added to cover all new functionality.

Differential Revision: https://reviews.llvm.org/D99401
2021-03-29 15:34:36 -07:00
Jonas Devlieghere 136d06749b [lldb] Fix XcodeSDKModuleTests
Update XcodeSDKModuleTests for YAMLModuleTester changes in D90393.
2020-10-30 23:08:35 -07:00
Pavel Labath a895a446bc [lldb/test] Simplify/generalize YAMLModuleTester
The class only supports a single DWARF unit (needed for my new test), and it
reimplements chunks of object and symbol file classes. We can just make it use
the real thing, save some LOC and get the full feature set.

Differential Revision: https://reviews.llvm.org/D90393
2020-10-30 14:27:50 +01:00
David Blaikie 0b05732045 fix lldb for recent libDebugInfoDWARF API change 2020-10-23 19:20:38 -07:00
Greg Clayton 79f22b1f99 Fix .debug_aranges parsing.
Code was added that used llvm error checking to parse .debug_aranges, but the error check after parsing the DWARFDebugArangesSet was reversed and was causing no error to be returned with no valid address ranges being actually used. This meant we always would fall back onto creating out own address ranges by parsing the compile unit's ranges. This was causing problems for cases where the DW_TAG_compile_unit had a single address range by using a DW_AT_low_pc and DW_AT_high_pc attribute pair (not using a DW_AT_ranges attribute), but the .debug_aranges had correct split ranges. In this case we would end up using the single range for the compile unit that encompassed all of the ranges from the .debug_aranges section and would cause address resolving issues in LLDB where address lookups would fail for certain addresses.

Differential Revision: https://reviews.llvm.org/D87626
2020-09-15 11:50:57 -07:00
Pavel Labath 0a2213c6eb [lldb/cmake] Fix testing support library dependencies
lldbUtilityHelpers does not depend on lldbSymbolHelpers. Remove that
dependency, and add direct lldbSymbolHelpers dependencies where needed.
2020-09-15 13:32:08 +02:00
Xing GUO 1d01fc100b [Test] Simplify DWARF test cases. NFC.
The Length, AbbrOffset and Values fields of the debug_info section are
optional. This patch helps remove them and simplify test cases.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D86857
2020-08-31 14:03:48 +08:00
Xing GUO 290e399f96 [DWARFYAML] Add support for emitting multiple abbrev tables.
This patch adds support for emitting multiple abbrev tables. Currently,
compilation units will always reference the first abbrev table.

Reviewed By: jhenderson, labath

Differential Revision: https://reviews.llvm.org/D86194
2020-08-21 10:12:08 +08:00
Adrian Prantl 6dbd4775bf Fix Windows build 2020-07-22 11:01:25 -07:00
Xing GUO 8632931787 [DWARFYAML] Make the length field of compilation units optional. NFC.
This patch makes the length field of compilation units optional (0 by
default).
2020-07-22 12:16:19 +08:00
Raphael Isemann bc163f6324 [lldb] Fix TestModuleGetXcodeSDK test after DWARFYAML change
D82622 / fe08ab542b changes the YAML format
so this test was failing as the test yaml wasn't updated.
2020-06-30 14:05:20 +02:00
Xing GUO fe08ab542b [DWARFYAML][debug_info] Replace 'InitialLength' with 'Format' and 'Length'.
'InitialLength' is replaced with 'Format' (DWARF32 by default) and 'Length' in this patch.
Besides, test cases for DWARFv4 and DWARFv5, DWARF32 and DWARF64 is
added.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D82622
2020-06-30 16:28:39 +08:00
Pavel Labath ba03bcbc4a [lldb] Remove custom DWARF expression printing code
The llvm DWARFExpression dump is nearly identical, but better -- for
example it does print a spurious space after zero-argument expressions.

Some parts of our code (variable locations) have been already switched
to llvm-based expression dumping. This switches the remainder: unwind
plans and some unit tests.
2020-05-25 16:09:25 +02:00
Adrian Prantl 01fc85dc96 ParseXcodeSDK: Register both the CU module and the SymbolFile module.
For Swift LLDB (but potentially also for module support in Clang-land)
we need a way to accumulate the path remappings produced by
Module::RegisterXcodeSDK(). In order to make this work for
SymbolFileDebugMaps, registering the search path remapping with both
modules is necessary.

Differential Revision: https://reviews.llvm.org/D79384

<rdar://problem/62750529>
2020-05-06 16:46:22 -07:00
Adrian Prantl 5935227e11 Add an explicit API to read the Xcode SDK DWARF attribute from compile units
When debugging from a SymbolMap the creation of CompileUnits for the
individual object files is so lazy that RegisterXcodeSDK() is not
invoked at all before the Swift TypeSystem wants to read it. This
patch fixes this by introducing an explicit
SymbolFile::ParseXcodeSDK() call that can be invoked deterministically
before the result is required.

<rdar://problem/62532151+62326862>

https://reviews.llvm.org/D79273
2020-05-06 13:16:16 -07:00
Adrian Prantl a0919ac080 Invert an #ifdef in XcodeSDKModuleTests.cpp and actually make the test work. 2020-04-24 18:39:40 -07:00
Adrian Prantl 06e4f69b22 Add a getter to retrieve the XcodeSDK from Module and unit-test it. (NFC)
This API is used by swift-lldb.

(Recommit with missing file git-added)
2020-04-24 17:00:34 -07:00
Adrian Prantl af015c1a33 Revert "Add a getter to retrieve the XcodeSDK from Module and unit-test it. (NFC)"
This reverts commit 345df863ce.

(Forgot to git-add the new file)
2020-04-24 16:59:48 -07:00
Adrian Prantl 345df863ce Add a getter to retrieve the XcodeSDK from Module and unit-test it. (NFC)
This API is used by swift-lldb.
2020-04-24 16:51:54 -07:00
Raphael Isemann e3fc6b3c34 [lldb][NFC] Fix unsigned/signed comparison warning in SymbolFileDWARFTest.cpp
offset_t is unsigned, so if the RHS is signed we get a warning from clang:
    warning: comparison of integers of different signs: 'const unsigned long long' and 'const int'
2020-03-12 15:30:11 +01:00
Luke Drummond 0fa3320931 [lldb] reject `.debug_arange` sections with nonzero segment size
If a producer emits a nonzero segment size, `lldb` will silently read
incorrect values and crash, or do something worse later as the tuple
size is expected to be 2, rather than 3.

Neither LLVM, nor GCC produce segmented aranges, but this dangerous case
should still be checked and handled.

Reviewed by: clayborg, labath
Differential Revision: https://reviews.llvm.org/D75925
Subscribers: lldb-commits
Tags: #lldb
2020-03-12 12:22:50 +00:00
Raphael Isemann 3f0661b5e7 [lldb][NFC] Fix compilation of SymbolFilePDBTests.cpp after FindNamespace API change
Since f9568a9549 this function takes a
CompilerDeclContext reference instead of a pointer. It overlooked this function
when I fixed the compilation for FindTypes.
2020-02-18 11:25:12 +01:00
Raphael Isemann 7d13812329 [lldb] Fix compilation of SymbolFilePDBTests.cpp after FindTypes API change
Since f9568a9549 this function takes a
CompilerDeclContext reference instead of a pointer.
2020-02-18 10:52:02 +01:00
Jonas Devlieghere f37b62ecce Re-land "[lldb] [testsuite] generalize `DWARFASTParserClangTests` based on `DWARFExpressionTest`'s YAML" 2020-02-04 13:59:29 -08:00
Jan Kratochvil b73f8c53d8 Revert: [lldb] [testsuite] generalize `DWARFASTParserClangTests` based on `DWARFExpressionTest`'s YAML
It is causing a failure on OSX, to be investigated more.

Differential Revision: https://reviews.llvm.org/D73279
2020-02-04 22:48:27 +01:00
Jan Kratochvil 2926a651ba [lldb] [testsuite] generalize `DWARFASTParserClangTests` based on `DWARFExpressionTest`'s YAML
YAMLModuleTester from DWARFExpressionTest can be reused for more
testcases.

Differential Revision: https://reviews.llvm.org/D73279
2020-02-04 14:33:29 +01:00
Alex Langford 8be30215fe [lldb] Move clang-based files out of Symbol
Summary:
This change represents the move of ClangASTImporter, ClangASTMetadata,
ClangExternalASTSourceCallbacks, ClangUtil, CxxModuleHandler, and
TypeSystemClang from lldbSource to lldbPluginExpressionParserClang.h

This explicitly removes knowledge of clang internals from lldbSymbol,
moving towards a more generic core implementation of lldb.

Reviewers: JDevlieghere, davide, aprantl, teemperor, clayborg, labath, jingham, shafik

Subscribers: emaste, mgorny, arphaman, jfb, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D73661
2020-01-31 12:20:10 -08:00
Raphael Isemann 808142876c [lldb][NFC] Fix all formatting errors in .cpp file headers
Summary:
A *.cpp file header in LLDB (and in LLDB) should like this:
```
//===-- TestUtilities.cpp -------------------------------------------------===//
```
However in LLDB most of our source files have arbitrary changes to this format and
these changes are spreading through LLDB as folks usually just use the existing
source files as templates for their new files (most notably the unnecessary
editor language indicator `-*- C++ -*-` is spreading and in every review
someone is pointing out that this is wrong, resulting in people pointing out that this
is done in the same way in other files).

This patch removes most of these inconsistencies including the editor language indicators,
all the different missing/additional '-' characters, files that center the file name, missing
trailing `===//` (mostly caused by clang-format breaking the line).

Reviewers: aprantl, espindola, jfb, shafik, JDevlieghere

Reviewed By: JDevlieghere

Subscribers: dexonsmith, wuzish, emaste, sdardis, nemanjai, kbarton, MaskRay, atanasyan, arphaman, jfb, abidh, jsji, JDevlieghere, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D73258
2020-01-24 08:52:55 +01:00
Raphael Isemann 6e3b0cc2fb [lldb][NFC] Rename ClangASTContext to TypeSystemClang
Summary:
This commit renames ClangASTContext to TypeSystemClang to better reflect what this class is actually supposed to do
(implement the TypeSystem interface for Clang). It also gets rid of the very confusing situation that we have both a
`clang::ASTContext` and a `ClangASTContext` in clang (which sometimes causes Clang people to think I'm fiddling
with Clang's ASTContext when I'm actually just doing LLDB work).

I also have plans to potentially have multiple clang::ASTContext instances associated with one ClangASTContext so
the ASTContext naming will then become even more confusing to people.

Reviewers: #lldb, aprantl, shafik, clayborg, labath, JDevlieghere, davide, espindola, jdoerfert, xiaobai

Reviewed By: clayborg, labath, xiaobai

Subscribers: wuzish, emaste, nemanjai, mgorny, kbarton, MaskRay, arphaman, jfb, usaxena95, jingham, xiaobai, abidh, JDevlieghere, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D72684
2020-01-23 10:09:14 +01:00
Raphael Isemann c9a39a896c [lldb] Add a display name to ClangASTContext instances
Summary:
I often struggle to understand what exactly LLDB is doing by looking at our expression evaluation logging as our messages look like this:
```
CompleteTagDecl[2] on (ASTContext*)0x7ff31f01d240 Completing (TagDecl*)0x7ff31f01d568 named DeclName1
```

From the log messages it's unclear what this ASTContext is. Is it the scratch context, the expression context, some decl vendor context or a context from a module?
The pointer value isn't helpful for anyone unless I'm in a debugger where I could inspect the memory at the address. But even with a debugger it's not easy to
figure out what this ASTContext is without having deeper understanding about all the different ASTContext instances in LLDB (e.g., valid SourceLocation
from the file system usually means that this is the Objective-C decl vendor, a file name from multiple expressions is probably the scratch context, etc.).

This patch adds a name field to ClangASTContext instances that we can use to store a name which can be used for logging and debugging. With this
our log messages now look like this:
```
CompleteTagDecl[2] on scratch ASTContext. Completing (TagDecl*)0x7ff31f01d568 named Foo
```
We can now also just print a ClangASTContext from the debugger and see a useful name in the `m_display_name` field, e.g.
```
  m_display_name = "AST for /Users/user/test/main.o";
```

Reviewers: shafik, labath, JDevlieghere, mib

Reviewed By: shafik

Subscribers: clayborg, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D72391
2020-01-22 08:54:10 +01:00
Raphael Isemann 518597c173 [lldb] Remove default llvm::Triple argument from ClangASTContext constructor
Creating an ASTContext with an unknown triple is rarely a good idea (as usually
all our ASTs have a valid triple that is either from the host or the target) and the
default argument makes it far to easy to implicitly create such an AST. Let's
remove it and force people to pass a triple.

The only place where we don't pass a triple is a DWARFASTParserClangTests
where we now just pass the host triple instead (the test doesn't depend on any
triple so this shouldn't change anything).
2020-01-08 12:05:51 +01:00
Raphael Isemann 73951a11c6 [lldb] Add sanity check to CreateDeclContext and fixed illformed CompilerContext in ClangExpressionDeclMap.
This adds a check that the ClangASTContext actually fits to the
DeclContext that we want to create a CompilerDeclContext for. If
the ClangASTContext (and its associated ASTContext) does not fit
to the DeclContext (that is, the DeclContext wasn't created by the
ASTContext), all computations using this malformed CompilerDeclContext
will yield unpredictable results.

Also fixes the only place that actually hits this assert which is the
construction of a CompilerDeclContext in ClangExpressionDeclMap
where we pass an unrelated ASTContext instead of the ASTContext
of the current expression.

I had to revert my previous change to DWARFASTParserClangTests.cpp
back to using the unsafe direct construction of CompilerDeclContext
as this assert won't work if the DeclContext we pass isn't a valid
DeclContext in the first place.
2019-12-23 11:48:02 +01:00
Raphael Isemann 5dca0596a9 [lldb] Add a SubsystemRAII that takes care of calling Initialize and Terminate in the unit tests
Summary:
Many of our tests need to initialize certain subsystems/plugins of LLDB such as
`FileSystem` or `HostInfo` by calling their static `Initialize` functions before the
test starts and then calling `::Terminate` after the test is done (in reverse order).
This adds a lot of error-prone boilerplate code to our testing code.

This patch adds a RAII called SubsystemRAII that ensures that we always call
::Initialize and then call ::Terminate after the test is done (and that the Terminate
calls are always in the reverse order of the ::Initialize calls). It also gets rid of
all of the boilerplate that we had for these calls.

Per-fixture initialization is still not very nice with this approach as it would
require some kind of static unique_ptr that gets manually assigned/reseted
from the gtest SetUpTestCase/TearDownTestCase functions. Because of that
I changed all per-fixture setup to now do per-test setup which can be done
by just having the SubsystemRAII as a member of the test fixture. This change doesn't
influence our normal test runtime as LIT anyway runs each test case separately
(and the Initialize/Terminate calls are anyway not very expensive). It will however
make running all tests in a single executable slightly slower.

Reviewers: labath, JDevlieghere, martong, espindola, shafik

Reviewed By: labath

Subscribers: mgorny, rnkovacs, emaste, MaskRay, abidh, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71630
2019-12-23 10:38:25 +01:00
Raphael Isemann 42ec584a8b [lldb][NFC] Make CompilerDeclContext construction type safe
The CompilerDeclContext constructor takes a void* pointer which
means that all callers of this constructor need to first explicitly
convert all pointers to clang::DeclContext*. This causes that we
for example can't just pass a TranslationUnitDecl* to the constructor without
first casting it to its parent class (as it inherits from both
Decl and DeclContext so the void* pointer is actually a Decl*).

This patch introduces a utility function in the ClangASTContext
which gets rid of the requirement to cast all pointers to
clang::DeclContext. Also moves all constructor calls to use this
function instead which is NFC (beside the change in
DWARFASTParserClangTests.cpp).
2019-12-23 09:56:54 +01:00
Raphael Isemann ceb433ad16 [lldb] Fix windows build after getASTContext() change 2019-12-21 23:27:27 +01:00
Pavel Labath 656a8123de [lldb] Fix windows build for 38870af 2019-11-29 12:48:25 +01:00
Adrian Prantl 3ebbda0f08 Adapt Windows test to API change.
llvm-svn: 375170
2019-10-17 20:51:55 +00:00
Raphael Isemann 2eb963abff [lldb][NFC] Create the ASTContext in ClangASTContext exactly once.
Reason for this patch is the Ssame reason as for the previous patches:
Having a ClangASTContext and being able to switch the associated ASTContext isn't
a use case we have (or should have), so let's simplify all this code.
This way it becomes clearer in what order we initialize data structures.

The DWARFASTParserClangTests changes are necessary as the test is using
a ClangASTContext but relied on the fact that no called function ever calls
getASTContext() on our ClangASTContext (as that would create the ASTContext).
As we now always create the ASTContext the fact that we had an uninitialized
FileSystem made the test crash.

llvm-svn: 373457
2019-10-02 12:26:08 +00:00
Adrian Prantl e2385e089d Make yet another attempt in restoring SymbolFilePDBTests
The original test was passing false to the append argument of
FindTypes (the only use of this feature!). This patch now replicates
that by passing a fresh TypeMap into the function where applicable.

llvm-svn: 373409
2019-10-02 00:06:27 +00:00
Adrian Prantl f3d2158616 Make another attempt at fixing SymbolFilePDBTests.
llvm-svn: 373373
2019-10-01 18:15:22 +00:00
Adrian Prantl dffe5dfa5c Fix a syntax error.
llvm-svn: 373355
2019-10-01 17:10:25 +00:00
Adrian Prantl bf9d84c014 Remove size_t return parameter from FindTypes
In r368345 I accidentally introduced a regression that would
over-report the number of matches found by FindTypes if the
DeclContext Filter was hit.

This patch simply removes the size_t return parameter altogether —
it's not that useful.

rdar://problem/55500457

Differential Revision: https://reviews.llvm.org/D68169

llvm-svn: 373344
2019-10-01 15:40:41 +00:00
Adrian Prantl b0ccef143a Try to update Windows unit test for API change.
llvm-svn: 373250
2019-09-30 19:38:52 +00:00
Pavel Labath 13a4e8f3ef Enhance SymbolFileDWARF::ParseDeclsForContext performance
This implements
DWARFASTParserClang::EnsureAllDIEsInDeclContextHaveBeenParsed so as to
provide a faster way to ensure all DIEs linked to a certain declaration
context have been parsed.

Currently, we rely on SymbolFileDWARF::ParseDeclsForContext calling
DWARFASTParserClang::GetDIEForDeclContext, and only then
DWARFASTParserClang::GetDeclForUIDFromDWARF. This change shortcuts that
logic and removes redundant calls to DWARFASTParserClang::
GetClangDeclForDIE by deleting DIEs from the m_decl_ctx_to_die map once
they have been parsed.

Differential Revision: https://reviews.llvm.org/D67760
Patch by Guilherme Andrade <guiandrade@google.com>.

llvm-svn: 372744
2019-09-24 12:36:54 +00:00