Commit Graph

27176 Commits

Author SHA1 Message Date
Balazs Benics cdacffe4ac [analyzer][z3] Use more elaborate Z3 variable names
Previously, it was a tedious task to comprehend Z3 dumps.
We will use the same name prefix just as we use in the corresponding dump method

For all `SymbolData` values:
    `$###` -> `conj_$###`
    `$###` -> `derived_$###`
    `$###` -> `extent_$###`
    `$###` -> `meta_$###`
    `$###` -> `reg_$###`

Reviewed By: xazax.hun,mikhail.ramalho

Differential Revision: https://reviews.llvm.org/D86223
2020-09-14 08:43:56 +02:00
Serge Pavlov f1cd6593da [AST][FPEnv] Keep FP options in trailing storage of CastExpr
This is recommit of 6c8041aa0f, reverted in de044f7562 because of some
fails. Original commit message is below.

This change allow a CastExpr to have optional FPOptionsOverride object,
stored in trailing storage. Of all cast nodes only ImplicitCastExpr,
CStyleCastExpr, CXXFunctionalCastExpr and CXXStaticCastExpr are allowed
to have FPOptions.

Differential Revision: https://reviews.llvm.org/D85960
2020-09-14 12:15:21 +07:00
Raphael Isemann c0bcd11068 [ASTImporter] Add basic support for comparing Stmts and compare function bodies
Right now the ASTImporter assumes for most Expr nodes that they are always equal
which leads to non-compatible declarations ending up being merged. This patch
adds the basic framework for comparing Stmts (and with that also Exprs) and
implements the custom checks for a few Stmt subclasses. I'll implement the
remaining subclasses in follow up patches (mostly because there are a lot of
subclasses and some of them require further changes like having GNU language in
the testing framework)

The motivation for this is that in LLDB we try to import libc++ source code and
some of the types we are importing there contain expressions (e.g. because they
use `enable_if<expr>`), so those declarations are currently merged even if they
are completely different (e.g. `enable_if<value> ...` and `enable_if<!value>
...` are currently considered equal which is clearly not true).

Reviewed By: martong, balazske

Differential Revision: https://reviews.llvm.org/D87444
2020-09-13 18:25:04 +02:00
Florian Hahn a874d63344 [Clang] Add option to allow marking pass-by-value args as noalias.
After the recent discussion on cfe-dev 'Can indirect class parameters be
noalias?' [1], it seems like using using noalias is problematic for
current C++, but should be allowed for C-only code.

This patch introduces a new option to let the user indicate that it is
safe to mark indirect class parameters as noalias. Note that this also
applies to external callers, e.g. it might not be safe to use this flag
for C functions that are called by C++ functions.

In targets that allocate indirect arguments in the called function, this
enables more agressive optimizations with respect to memory operations
and brings a ~1% - 2% codesize reduction for some programs.

[1] : http://lists.llvm.org/pipermail/cfe-dev/2020-July/066353.html

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D85473
2020-09-12 14:56:13 +01:00
Serge Pavlov de044f7562 Revert "[AST][FPEnv] Keep FP options in trailing storage of CastExpr"
This reverts commit 6c8041aa0f.
It caused some fails on buildbots.
2020-09-12 17:06:42 +07:00
Serge Pavlov 6c8041aa0f [AST][FPEnv] Keep FP options in trailing storage of CastExpr
This change allow a CastExpr to have optional FPOptionsOverride object,
stored in trailing storage. Of all cast nodes only ImplicitCastExpr,
CStyleCastExpr, CXXFunctionalCastExpr and CXXStaticCastExpr are allowed
to have FPOptions.

Differential Revision: https://reviews.llvm.org/D85960
2020-09-12 14:30:44 +07:00
Zequan Wu 83286a1a8f [MS ABI] Add mangled type for auto template parameter whose argument kind is Integeral 2020-09-11 16:19:43 -07:00
Saleem Abdulrasool 43e6c59f1c docs: add a newline to appease Sphinx
Sphinx expects an empty newline after the bulleted list.
2020-09-11 22:09:29 +00:00
Saleem Abdulrasool f5ab5b20fb Sema: add support for `__attribute__((__swift_error__))`
Introduce a new attribute that is used to indicate the error handling
convention used by a function.  This is used to translate the error
semantics from the decorated interface to a compatible Swift interface.

The supported error convention is one of:
- none: no error handling
- nonnull_error: a non-null error parameter indicates an error signifier
- null_result: a return value of NULL is an error signifier
- zero_result: a return value of 0 is an error signifier
- nonzero_result: a non-zero return value is an error signifier

Since this is the first of the attributes needed to support the semantic
annotation for Swift, this change also includes the necessary supporting
infrastructure for a new category of attributes (Swift).

This is based on the work of the original changes in
8afaf3aad2

Differential Revision: https://reviews.llvm.org/D87331
Reviewed By: John McCall, Aaron Ballman, Dmitri Gribenko
2020-09-11 21:20:38 +00:00
Eduardo Caldas 7c37b82f5b [SyntaxTree][Synthesis] Add support for Tree.
In a future patch
* Implement helper function to generate Trees for tests
* and test Tree methods, namely `findFirstLeaf` and `findLastLeaf`

Differential Revision: https://reviews.llvm.org/D87533
2020-09-11 20:37:23 +00:00
Eduardo Caldas 515238d5b1 [SyntaxTree] Reduce visibility of `Arena::lexBuffer`.
Differential Revision: https://reviews.llvm.org/D87523
2020-09-11 18:32:38 +00:00
Eduardo Caldas 5d152127d4 [SyntaxTree][Synthesis] Add support for simple Leafs and test based on tree dump
Differential Revision: https://reviews.llvm.org/D87495
2020-09-11 18:22:00 +00:00
Eduardo Caldas 4c14ee61b7 [SyntaxTree] Rename functions to start with verb
According to LLVM coding standards:
https://llvm.org/docs/CodingStandards.html#name-types-functions-variables-and-enumerators-properly

Differential Revision: https://reviews.llvm.org/D87498
2020-09-11 14:54:18 +00:00
Kristóf Umann b9bca883c9 [analyzer][NFC] Don't bind values to ObjCForCollectionStmt, replace it with a GDM trait
Based on the discussion in D82598#2171312. Thanks @NoQ!

D82598 is titled "Get rid of statement liveness, because such a thing doesn't
exist", and indeed, expressions express a value, non-expression statements
don't.

if (a && get() || []{ return true; }())
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ has a value
    ~ has a value
    ~~~~~~~~~~ has a value
                  ~~~~~~~~~~~~~~~~~~~~ has a value
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ doesn't have a value

That is simple enough, so it would only make sense if we only assigned symbolic
values to expressions in the static analyzer. Yet the interface checkers can
access presents, among other strange things, the following two methods:

ProgramState::BindExpr(const Stmt *S, const LocationContext *LCtx, SVal V,
                       bool Invalidate=true)
ProgramState::getSVal(const Stmt *S, const LocationContext *LCtx)

So, what gives? Turns out, we make an exception for ReturnStmt (which we'll
leave for another time) and ObjCForCollectionStmt. For any other loops, in order
to know whether we should analyze another iteration, among other things, we
evaluate it's condition. Which is a problem for ObjCForCollectionStmt, because
it simply doesn't have one (CXXForRangeStmt has an implicit one!). In its
absence, we assigned the actual statement with a concrete 1 or 0 to indicate
whether there are any more iterations left. However, this is wildly incorrect,
its just simply not true that the for statement has a value of 1 or 0, we can't
calculate its liveness because that doesn't make any sense either, so this patch
turns it into a GDM trait.

Fixing this allows us to reinstate the assert removed in
https://reviews.llvm.org/rG032b78a0762bee129f33e4255ada6d374aa70c71.

Differential Revision: https://reviews.llvm.org/D86736
2020-09-11 15:58:48 +02:00
Caroline Concatto 257b29715b [flang][driver] Add the new flang compiler and frontend drivers
Summary:

This is the first patch implementing the new Flang driver as outlined in [1],
[2] & [3]. It creates Flang driver (`flang-new`) and Flang frontend driver
(`flang-new -fc1`). These will be renamed as `flang` and `flang -fc1` once the
current Flang throwaway driver, `flang`, can be replaced with `flang-new`.

Currently only 2 options are supported: `-help` and `--version`.

`flang-new` is implemented in terms of libclangDriver, defaulting the driver
mode to `FlangMode` (added to libclangDriver in [4]). This ensures that the
driver runs in Flang mode regardless of the name of the binary inferred from
argv[0].

The design of the new Flang compiler and frontend drivers is inspired by it
counterparts in Clang [3]. Currently, the new Flang compiler and frontend
drivers re-use Clang libraries: clangBasic, clangDriver and clangFrontend.

To identify Flang options, this patch adds FlangOption/FC1Option enums.
Driver::printHelp is updated so that `flang-new` prints only Flang options.
The new Flang driver is disabled by default. To enable it, set
`-DBUILD_FLANG_NEW_DRIVER=ON` when configuring CMake and add clang to
`LLVM_ENABLE_PROJECTS` (e.g. -DLLVM_ENABLE_PROJECTS=“clang;flang;mlir”).

[1] “RFC: new Flang driver - next steps”
http://lists.llvm.org/pipermail/flang-dev/2020-July/000470.html
[2] “RFC: Adding a fortran mode to the clang driver for flang”
http://lists.llvm.org/pipermail/cfe-dev/2019-June/062669.html
[3] “RFC: refactoring libclangDriver/libclangFrontend to share with Flang”
http://lists.llvm.org/pipermail/cfe-dev/2020-July/066393.html
[4] https://reviews.llvm.org/rG6bf55804924d5a1d902925ad080b1a2b57c5c75c

co-authored-by: Andrzej Warzynski <andrzej.warzynski@arm.com>

Reviewed By: richard.barton.arm, sameeranjoshi

Differential Revision: https://reviews.llvm.org/D86089
2020-09-11 10:55:54 +01:00
Mark de Wever 08196e0b2e Implements [[likely]] and [[unlikely]] in IfStmt.
This is the initial part of the implementation of the C++20 likelihood
attributes. It handles the attributes in an if statement.

Differential Revision: https://reviews.llvm.org/D85091
2020-09-09 20:48:37 +02:00
Eduardo Caldas c0e5e3fbfa [Ignore Expressions] Fix performance regression by inlining `Ignore*SingleStep`
We also add a `const` versions of `IgnoreExprNodes`

Differential Revision: https://reviews.llvm.org/D87278
2020-09-09 07:32:40 +00:00
Saleem Abdulrasool f4ac79a364 Sema: extract a check for `isCFError` (NFC)
Extract a simple check to check if a `RecordDecl` is a `CFError` Decl.
This is a simple refactoring to prepare for an upcoming change.  NFC.

Patch is extracted from
8afaf3aad2.
2020-09-08 20:07:47 +00:00
Ties Stuij d6f3f61231 Revert "[ARM] Follow AACPS standard for volatile bit-fields access width"
This reverts commit 514df1b2bb.

Some of the buildbots got llvm-lit errors on CodeGen/volatile.c
2020-09-08 18:46:27 +01:00
Ties Stuij 514df1b2bb [ARM] Follow AACPS standard for volatile bit-fields access width
This patch resumes the work of D16586.
According to the AAPCS, volatile bit-fields should
be accessed using containers of the widht of their
declarative type. In such case:
```
struct S1 {
  short a : 1;
}
```
should be accessed using load and stores of the width
(sizeof(short)), where now the compiler does only load
the minimum required width (char in this case).
However, as discussed in D16586,
that could overwrite non-volatile bit-fields, which
conflicted with C and C++ object models by creating
data race conditions that are not part of the bit-field,
e.g.
```
struct S2 {
  short a;
  int  b : 16;
}
```
Accessing `S2.b` would also access `S2.a`.

The AAPCS Release 2020Q2
(https://documentation-service.arm.com/static/5efb7fbedbdee951c1ccf186?token=)
section 8.1 Data Types, page 36, "Volatile bit-fields -
preserving number and width of container accesses" has been
updated to avoid conflict with the C++ Memory Model.
Now it reads in the note:
```
This ABI does not place any restrictions on the access widths of bit-fields where the container
overlaps with a non-bit-field member or where the container overlaps with any zero length bit-field
placed between two other bit-fields. This is because the C/C++ memory model defines these as being
separate memory locations, which can be accessed by two threads simultaneously. For this reason,
compilers must be permitted to use a narrower memory access width (including splitting the access into
multiple instructions) to avoid writing to a different memory location. For example, in
struct S { int a:24; char b; }; a write to a must not also write to the location occupied by b, this requires at least two
memory accesses in all current Arm architectures. In the same way, in struct S { int a:24; int:0; int b:8; };,
writes to a or b must not overwrite each other.
```

Patch D16586 was updated to follow such behavior by verifying that we
only change volatile bit-field access when:
 - it won't overlap with any other non-bit-field member
 - we only access memory inside the bounds of the record
 - avoid overlapping zero-length bit-fields.

Regarding the number of memory accesses, that should be preserved, that will
be implemented by D67399.

Differential Revision: https://reviews.llvm.org/D72932

The following people contributed to this patch:
- Diogo Sampaio
- Ties Stuij
2020-09-08 17:49:49 +01:00
Hans Wennborg 2d9d270e77 Revert 3e782bf809 "[Sema][MSVC] warn at dynamic_cast when /GR- is given"
This caused more warnings than expected, see https://crbug.com/1126019

Also reverts the follow-up 7907e5516.

> Differential Revision: https://reviews.llvm.org/D86369
2020-09-08 16:10:18 +02:00
Haojian Wu 9c9974c3cc [clang] Limit the maximum level of fold-expr expansion.
Introduce a new diagnostic, and respect the bracket-depth (256) by default.

Differential Revision: https://reviews.llvm.org/D86936
2020-09-08 15:40:09 +02:00
Martin Storsjö 28b9ace85f [clang] Remove a stray semicolon, fixing pedantic GCC warnings. NFC. 2020-09-08 09:26:39 +03:00
Zequan Wu 3e782bf809 [Sema][MSVC] warn at dynamic_cast when /GR- is given
Differential Revision: https://reviews.llvm.org/D86369
2020-09-07 16:46:58 -07:00
Gabor Marton 8248c2af94 [analyzer][StdLibraryFunctionsChecker] Have proper weak dependencies
We want the generice StdLibraryFunctionsChecker to report only if there
are no specific checkers that would handle the argument constraint for a
function.

Note, the assumptions are still evaluated, even if the arguement
constraint checker is set to not report. This means that the assumptions
made in the generic StdLibraryFunctionsChecker should be an
over-approximation of the assumptions made in the specific checkers. But
most importantly, the assumptions should not contradict.

Differential Revision: https://reviews.llvm.org/D87240
2020-09-07 17:56:26 +02:00
Eduardo Caldas 1a7a2cd747 [Ignore Expressions][NFC] Refactor to better use `IgnoreExpr.h` and nits
This change groups
* Rename: `ignoreParenBaseCasts` -> `IgnoreParenBaseCasts` for uniformity
* Rename: `IgnoreConversionOperator` -> `IgnoreConversionOperatorSingleStep` for uniformity
* Inline `IgnoreNoopCastsSingleStep` into a lambda inside `IgnoreNoopCasts`
* Refactor `IgnoreUnlessSpelledInSource` to make adequate use of `IgnoreExprNodes`

Differential Revision: https://reviews.llvm.org/D86880
2020-09-07 09:32:30 +00:00
Eduardo Caldas 81aa66f65f Extract infrastructure to ignore intermediate expressions into `clang/AST/IgnoreExpr.h`
Rationale:
This allows users to use `IgnoreExprNodes` and `Ignore*SingleStep` outside of
`clang/AST/Expr.cpp`.

Minor:
Rename `IgnoreImp...SingleStep`  into `IgnoreImplicit...SingleStep`.

Differential Revision: https://reviews.llvm.org/D86778
2020-09-07 09:32:30 +00:00
Alex Richardson e7bd058c7e [clang-format] Allow configuring list of macros that map to attributes
This adds a `AttributeMacros` configuration option that causes certain
identifiers to be parsed like a __attribute__((foo)) annotation.
This is motivated by our CHERI C/C++ fork which adds a __capability
qualifier for pointer/reference. Without this change clang-format parses
many type declarations as multiplications/bitwise-and instead.
I initially considered adding "__capability" as a new clang-format keyword,
but having a list of macros that should be treated as attributes is more
flexible since it can be used e.g. for static analyzer annotations or other language
extensions.

Example: std::vector<foo * __capability> -> std::vector<foo *__capability>

Depends on D86775 (to apply cleanly)

Reviewed By: MyDeveloperDay, jrtc27

Differential Revision: https://reviews.llvm.org/D86782
2020-09-07 10:09:17 +01:00
Amy Kwan efa57f9a7a [PowerPC] Implement Vector Expand Mask builtins in LLVM/Clang
This patch implements the vec_expandm function prototypes in altivec.h in order
to utilize the vector expand with mask instructions introduced in Power10.

Differential Revision: https://reviews.llvm.org/D82727
2020-09-06 17:13:21 -05:00
Benjamin Kramer 4d0312c8e0 Add proper move ctor/move assign to APValue. NFCI.
Swapping 64 bytes to make a move isn't cheap.
2020-09-06 13:02:11 +02:00
Aaron Puchert d3a779fe21 Restore size of TemplateParameterList after D44352
After adding a field of one bit, the bitfield members would take
30+1+1+1 = 33 bits, causing the size of TemplateParameterList to
increase from 16 to 24 bytes on 64-bit systems.

With 29 bits for NumParams we can encode up to half a billion template
parameters, which is almost certainly still enough for anybody.
2020-09-05 18:01:33 +02:00
Pengxuan Zheng 2bccd2b435 [Driver] Allow -specs and -nostartfiles to be forwarded to GCC
With 6a75496836, these two options are no longer
forwarded to GCC. This patch restores the original behavior.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D87162
2020-09-04 15:09:33 -07:00
Jan Korous 69e5abb57b [libclang] Add CXRewriter to libclang API
Differential Revision: https://reviews.llvm.org/D86992
2020-09-04 14:17:03 -07:00
Jan Korous 052f838903 [libclang] Expose couple more AST details via cursors
Differential Revision: https://reviews.llvm.org/D86991
2020-09-04 13:38:47 -07:00
Teresa Johnson 45c3560384 [HeapProf] Address post-review comments in instrumentation code
Addresses post-review comments from D85948, which can be found here:
https://reviews.llvm.org/rG7ed8124d46f9.
2020-09-04 08:59:00 -07:00
Nico Weber 7b0332389a Revert "Canonicalize declaration pointers when forming APValues."
This reverts commit e6393ee813.
It breaks Wunreachable for weak attributes, see
http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20200831/336645.html
2020-09-04 10:13:28 -04:00
Vaibhav Garg 2c9dbcda4f [modules] Correctly parse LateParsedTemplates in case of dependent modules.
While parsing LateParsedTemplates, Clang assumes that the Global DeclID matches
with the Local DeclID of a Decl. This is not the case when we have multiple
dependent modules , each having their own LateParsedTemplate section. In such a
case, a Local/Global DeclID confusion occurs which leads to improper casting of
FunctionDecl's.

This commit creates a Vector to map the LateParsedTemplate section of each
Module with their module file and therefore resolving the Global/Local DeclID
confusion.

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D86514
2020-09-04 11:39:04 +00:00
Serge Pavlov a633da5391 [FPEnv] Partially implement #pragma STDC FENV_ROUND
This change implements pragma STDC FENV_ROUND, which is introduced by
the extension to standard (TS 18661-1). The pragma is implemented only
in frontend, it sets apprpriate state of FPOptions stored in Sema. Use
of these bits in constant evaluation adn/or code generator is not in the
scope of this change.

Parser issues warning on unsuppored pragma when it encounteres pragma
STDC FENV_ROUND, however it makes syntax checks and updates Sema state
as if the pragma were supported.

Primary purpose of the partial implementation is to facilitate
development of non-default floating poin environment. Previously a
developer cannot set non-default rounding mode in sources, this mades
preparing tests for say constant evaluation  substantially complicated.

Differential Revision: https://reviews.llvm.org/D86921
2020-09-04 16:47:10 +07:00
Richard Smith 052dbe226c Remove unused and dangerous overload of PerformImplicitConversion.
Previously we had two overloads where the only real difference beyond
parameter order was whether a reference parameter is const, where one
overload treated the reference parameter as an in-parameter and the
other treated it as an out-parameter!
2020-09-03 15:35:12 -07:00
Richard Smith e6393ee813 Canonicalize declaration pointers when forming APValues.
References to different declarations of the same entity aren't different
values, so shouldn't have different representations.
2020-09-03 15:35:12 -07:00
Yitzhak Mandelbaum d4f3903131 [libTooling] Provide overloads of `rewriteDescendants` that operate directly on an AST node.
The new overloads apply directly to a node, like the
`clang::ast_matchers::match` functions, Rather than generating an
`EditGenerator` combinator.

Differential Revision: https://reviews.llvm.org/D87031
2020-09-03 14:39:50 +00:00
Cullen Rhodes f9091e56d3 [clang][aarch64] Drop experimental from __ARM_FEATURE_SVE_BITS macro
The __ARM_FEATURE_SVE_BITS feature macro is specified in the Arm C
Language Extensions (ACLE) for SVE [1] (version 00bet5). From the spec,
where __ARM_FEATURE_SVE_BITS==N:

    When N is nonzero, indicates that the implementation is generating
    code for an N-bit SVE target and that the arm_sve_vector_bits(N)
    attribute is available.

This was defined in D83550 as __ARM_FEATURE_SVE_BITS_EXPERIMENTAL and
enabled under the -msve-vector-bits flag to simplify initial tests.
This patch drops _EXPERIMENTAL now there is support for the feature.

[1] https://developer.arm.com/documentation/100987/latest

Reviewed By: david-arm

Differential Revision: https://reviews.llvm.org/D86720
2020-09-03 09:39:37 +00:00
Craig Topper ca134374b7 [X86] Add a /tune: option for clang-cl
We recently added support for -mtune. This patch adds /tune: so we can specify the tune CPU from clang-cl. MSVC doesn't support this but icc does.

Differential Revision: https://reviews.llvm.org/D86820
2020-09-02 20:27:38 -07:00
Adrian Prantl 3b12e12d4b Revert "[clang] Add missing .def files to Clang's modulemap"
This reverts commit e0e7eb2e26.

[the commit this fixes up was reverted]
2020-09-02 14:15:32 -07:00
Yaxun (Sam) Liu 62dbb7e54c Revert "[HIP] Change default --gpu-max-threads-per-block value to 1024"
Temporarily revert commit 04abbb3a78
due to regressions in some HIP apps due backend issues revealed by
this change.

Will re-commit it when backend issues are fixed.
2020-09-02 16:12:28 -04:00
Albion Fung 5d1fe3f903 [PowerPC] Implemented Vector Multiply Builtins
This patch implements the builtins for Vector Multiply Builtins (vmulxxd family of instructions), and adds the appropriate test cases for these builtins. The builtins utilize the vector multiply instructions itnroduced with ISA 3.1.

Differential Revision: 	https://reviews.llvm.org/D83955
2020-09-02 14:16:21 -05:00
Erik Pilkington 9523cf02c2 [AST] Fix handling of long double and bool in __builtin_bit_cast
On x86, long double has 6 unused trailing bytes. This patch changes the
constant evaluator to treat them as though they were padding bytes, so reading
from them results in an indeterminate value, and nothing is written for them.
Also, fix a similar bug with bool, but instead of treating the unused bits as
padding, enforce that they're zero.

Differential revision: https://reviews.llvm.org/D76323
2020-09-02 15:01:53 -04:00
Raphael Isemann e0e7eb2e26 [clang] Add missing .def files to Clang's modulemap
These new .def files weren't marked as textual so they ended up being compiled
into the Clang module (which completely defeats the purpose of .def files).
2020-09-02 20:42:12 +02:00
Douglas Yung 8d2d0e8485 Revert "Move all fields of '-cc1' option related classes into def file databases"
This reverts commit c4a2a13074.

This commit was causing a test failure: http://lab.llvm.org:8011/builders/llvm-clang-win-x-armv7l/builds/1068
2020-09-02 10:38:34 -07:00
Erik Pilkington d46f2c51e4 Make -fvisibility-inlines-hidden apply to static local variables in inline functions on Darwin
This effectively disables r340386 on Darwin, and provides a command line flag
to opt into/out of this behaviour. This change is needed to compile certain
Apple headers correctly.

rdar://47688592

Differential revision: https://reviews.llvm.org/D86881
2020-09-02 12:19:12 -04:00