- Introduce a skeleton outline for the GOFFAsmParser
- Before instantiating AsmParser/HLASMAsmParser, target specific asm parsers are attempted to be initialized first before proceeding. If it doesn't exist for a particular file type, we report a fatal error.
- This patch allows to properly instantiate the HLASMAsmParser on z/OS, and ensures we can write lit tests and unit tests which will involve the instantiation of asm parsers, without an assert / fatal error.
Reviewed By: uweigand, Kai
Differential Revision: https://reviews.llvm.org/D110730
The call to emitCodeAlignment was missing a STI which is required
after D45962.
emitCodeAlignment has a default parameter of 0 for MaxBytesToEmit.
Explicitly passing 0 here was interpreted as as nullptr for the STI.
This could possibly be avoided by taking STI as a const reference in
emitCodeAlignment.
Differential Revision: https://reviews.llvm.org/D109425
In preparation for passing the MCSubtargetInfo (STI) through to writeNops
so that it can use the STI in operation at the time, we need to record the
STI in operation when a MCAlignFragment may write nops as padding. The
STI is currently unused, a further patch will pass it through to
writeNops.
There are many places that can create an MCAlignFragment, in most cases
we can find out the STI in operation at the time. In a few places this
isn't possible as we are in initialisation or finalisation, or are
emitting constant pools. When possible I've tried to find the most
appropriate existing fragment to obtain the STI from, when none is
available use the per module STI.
For constant pools we don't actually need to use EmitCodeAlign as the
constant pools are data anyway so falling through into it via an
executable NOP is no better than falling through into data padding.
This is a prerequisite for D45962 which uses the STI to emit the
appropriate NOP for the STI. Which can differ per fragment.
Note that involves an interface change to InitSections. It is now
called initSections and requires a SubtargetInfo as a parameter.
Differential Revision: https://reviews.llvm.org/D45961
Fixes issue: https://bugs.llvm.org/show_bug.cgi?id=47983
The AsmLexer currently has an issue with lexing line comments in files
with CRLF line endings, in which it reads the carriage return as being
part of the line comment. This causes an error for certain valid comment
layouts; this patch fixes this by excluding the carriage return from the
line comment.
Differential Revision: https://reviews.llvm.org/D90234
MIPS .debug_* sections should have SHT_MIPS_DWARF section type to
distinguish among sections contain DWARF and ECOFF debug formats, but in
assembly files these sections have SHT_PROGBITS (@progbits) type. Now
assembler shows 'changed section type for ...' error when parsing
`.section .debug_*,"",@progbits` directive for MIPS targets.
The same problem exists for x86-64 target and this patch extends
workaround implemented in D76151. The patch adds one more case
when assembler ignores section types mismatch after `SwitchSection()`
call.
Differential Revision: https://reviews.llvm.org/D107707
Previously we would emit constant pool entries for ldr inline asm at the
very end of AsmPrinter::doFinalization(). However, if we're emitting
dwarf aranges, that would end all sections with aranges. Then if we have
constant pool entries to be emitted in those same sections, we'd hit an
assert that the section has already been ended.
We want to emit constant pool entries before emitting dwarf aranges.
This patch splits out arm32/64's constant pool entry emission into its
own MCTargetStreamer virtual method.
Fixes PR51208
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D107314
- This patch consists of the bare basic code needed in order to generate some assembly for the z/OS target.
- Only the .text and the .bss sections are added for now.
- The relevant MCSectionGOFF/Symbol interfaces have been added. This enables us to print out the GOFF machine code sections.
- This patch enables us to add simple lit tests wherever possible, and contribute to the testing coverage for the z/OS target
- Further improvements and additions will be made in future patches.
Reviewed By: tmatheson
Differential Revision: https://reviews.llvm.org/D106380
We previously had issues identifying macros not registered with a lowercase name.
Reviewed By: mstorsjo, thakis
Differential Revision: https://reviews.llvm.org/D106453
Add support for all built-in text macros supported by ML64:
@Date, @Time, @FileName, @FileCur, and @CurSeg.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D104965
Support @Version and @Line as built-in symbols. For now, resolves @Version to 1427 (the same as for the VS 2019 release of ML.EXE).
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D104964
No implementation uses the `LocCookie` parameter at all. Errors are
reported from inside that function by `llvm::SourceMgr`, and the
instance of that at the clang call site arranges to pass the error
messages back to a `ClangAsmParserCallback`, which is where the clang
SourceLocation for the error is computed.
(This is part of a patch series working towards the ability to make
SourceLocation into a 64-bit type to handle larger translation units.
But this particular change seems beneficial in its own right.)
Reviewed By: miyuki
Differential Revision: https://reviews.llvm.org/D105490
In MASM, the ifdef family of directives treats its argument literally, without expanding it as a text macro. Add support for this, and also replace the special handling that was previously used for echo.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D104196
Implement XCOFFMCAsmParser so that we can use MC to parse inline asm.
The directives and storage mapping classes will be added later
iteratively.
Reviewed By: xgupta
Differential Revision: https://reviews.llvm.org/D105259
Enable the emission of a GNU attributes section by reusing the code for
emitting the ARM build attributes section.
The GNU attributes follow the exact same section format as the ARM
BuildAttributes section, so this can be factored out and reused for GNU
attributes generally.
The immediate motivation for this is to emit a GNU attributes section for the
vector ABI on SystemZ (https://reviews.llvm.org/D105067).
Review: Logan Chien, Ulrich Weigand
Differential Revision: https://reviews.llvm.org/D102894
- In the caller of the overridden `parseStatement` function (i.e. the `AsmParser::Run()`) in the case of an error **and** if we're not at the start of the statement, we "eat" up until the end of the current statement, so we don't have to process it again.
- However, in the HLASMAsmParser class what's happening is that, if an error occurs at the very start of the statement (for example, you invoke the HLASMAsmParser to parse a gnu directive), we will error out, but we never really progress in terms of the next token in the statement to parse. We simply keep looping processing the same error over and over again (partly because we're at the start of the statement)
- To remedy this, when the `parseAsHLASMLabel` function fails, before returning, we "eat" until the end of the statement function, so we don't process it anymore.
Reviewed By: uweigand
Differential Revision: https://reviews.llvm.org/D104869
Match ML.EXE's behavior for ALIGN, EVEN, and ORG directives both at file level and in STRUCTs.
We currently reject negative offsets passed to ORG inside STRUCTs (in ML.EXE and ML64.EXE, they wrap around as for an unsigned 32-bit integer).
Also, if a STRUCT is declared using an ORG directive, no value of that type can be defined.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D92507
This is a mechanical change. This actually also renames the
similarly named methods in the SmallString class, however these
methods don't seem to be used outside of the llvm subproject, so
this doesn't break building of the rest of the monorepo.
- Currently, the emitting of labels in the parsePrimaryExpr function is case independent. It just takes the identifier and emits it.
- However, for HLASM the emitting of labels is case independent. We are emitting them in the upper case only, to enforce case independency. So we need to ensure that at the time of parsing the label we are emitting the upper case (in `parseAsHLASMLabel`), but also, when we are processing a PC-relative relocatable expression, we need to ensure we emit it in upper case (in `parsePrimaryExpr`)
- To achieve this a new MCAsmInfo attribute has been introduced which corresponding targets can override if needed.
Reviewed By: abhina.sreeskantharajan, uweigand
Differential Revision: https://reviews.llvm.org/D104715
If a macro is defined on the command line and then overridden in the source code, this is likely to be an error in the user's build system. We should warn on this.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D104008
MASM specifies that all variable definitions are redefinable, except for EQU definitions to expressions. (TEXTEQU is unspecified, but appears to be fully redefinable as well.)
Also, in practice, ML.EXE allows redefinitions where the value doesn't change.
Make variable redefinition possible for text macros, suppressing expansion if written as the first argument to an EQU or TEXTEQU directive.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D103993
- A lot of lit tests simply specify the arch minus the triple. On z/OS, this could result in a scenario of some-other-triple-unknown-ibm-zos. This points to an incorrect triple + arch combo.
- To prevent this, isOSzOS change is switched in favour of isOSBinFormatGOFF.
- This is because, the GOFF format is set only if the triple is systemz and if the operating system is GOFF. And currently, there are no other architectures/os's using the GOFF file format.
- An argument could be made that the problematic tests be fixed to explicitly specify the arch-vendor-triple string, but there's a large number of these tests, and adding this stricter scope ensures that we aren't instantiating the incorrect instance of the AsmParser for other platforms when run on z/OS.
Reviewed By: uweigand
Differential Revision: https://reviews.llvm.org/D103343
- This patch is the second (and hopefully final) part of providing HLASM syntax for inline asm statements for z/OS to LLVM (continuing on from https://reviews.llvm.org/D98276)
- This second part deals with providing label support
- As mentioned in https://reviews.llvm.org/D98276, if the first token is not a space we process the first token as a label, and the remaining tokens as a possible machine instruction
- To achieve this, a new `parseAsHLASMLabel` function is introduced. This function processes the first token, validates whether it is an "acceptable" label according to HLASM standards, and then emits it
- After handling and emitting the label, call the `parseAsMachineInstruction` instruction to process the remaining tokens as a machine instruction.
Reviewed By: uweigand
Differential Revision: https://reviews.llvm.org/D103320
- This patch (is one in a series of patches) which introduces HLASM Parser support (for the first parameter of inline asm statements) to LLVM ([[ https://lists.llvm.org/pipermail/llvm-dev/2021-January/147686.html | main RFC here ]])
- This patch in particular introduces HLASM Parser support for Z machine instructions.
- The approach taken here was to subclass `AsmParser`, and make various functions and variables as "protected" wherever appropriate.
- The `HLASMAsmParser` class overrides the `parseStatement` function. Two new private functions `parseAsHLASMLabel` and `parseAsMachineInstruction` are introduced as well.
The general syntax is laid out as follows (more information available in [[ https://www.ibm.com/support/knowledgecenter/SSENW6_1.6.0/com.ibm.hlasm.v1r6.asm/asmr1023.pdf | HLASM V1R6 Language Reference Manual ]] - Chapter 2 - Instruction Statement Format):
```
<TokA><spaces.*><TokB><spaces.*><TokC><spaces.*><TokD>
```
1. TokA is referred to as the Name Entry. This token is optional
2. TokB is referred to as the Operation Entry. This token is mandatory.
3. TokC is referred to as the Operand Entry. This token is mandatory
4. TokD is referred to as the Remarks Entry. This token is optional
- If TokA is provided, then we either parse TokA as a possible comment or as a label (Name Entry), Tok B as the Operation Entry and so on.
- If TokA is not provided (i.e. we have one or more spaces and then the first token), then we will parse the first token (i.e TokB) as a possible Z machine instruction, TokC as the operands to the Z machine instruction and TokD as a possible Remark field
- TokC (Operand Entry), no spaces are allowed between OperandEntries. If a space occurs it is classified as an error.
- TokD if provided is taken as is, and emitted as a comment.
The following additional approach was examined, but not taken:
- Adding custom private only functions to base AsmParser class, and only invoking them for z/OS. While this would eliminate the need for another child class, these private functions would be of non-use to every other target. Similarly, adding any pure virtual functions to the base MCAsmParser class and overriding them in AsmParser would also have the same disadvantage.
Testing:
- This patch doesn't have tests added with it, for the sole reason that MCStreamer Support and Object File support hasn't been added for the z/OS target (yet). Hence, it's not possible generate code outright for the z/OS target. They are in the process of being committed / process of being worked on.
- Any comments / feedback on how to combat this "lack of testing" due to other missing required features is appreciated.
Reviewed By: Kai, uweigand
Differential Revision: https://reviews.llvm.org/D98276
This change was originally landed in: 5000a1b4b9
It was reverted in: 061e071d8c
This change adds support for a new WASM_SEG_FLAG_STRINGS flag in
the object format which works in a similar fashion to SHF_STRINGS
in the ELF world.
Unlike the ELF linker this support is currently limited:
- No support for SHF_MERGE (non-string merging)
- Always do full tail merging ("lo" can be merged with "hello")
- Only support single byte strings (p2align 0)
Like the ELF linker merging is only performed at `-O1` and above.
This fixes part of https://bugs.llvm.org/show_bug.cgi?id=48828,
although crucially it doesn't not currently support debug sections
because they are not represented by data segments (they are custom
sections)
Differential Revision: https://reviews.llvm.org/D97657
This change adds support for a new WASM_SEG_FLAG_STRINGS flag in
the object format which works in a similar fashion to SHF_STRINGS
in the ELF world.
Unlike the ELF linker this support is currently limited:
- No support for SHF_MERGE (non-string merging)
- Always do full tail merging ("lo" can be merged with "hello")
- Only support single byte strings (p2align 0)
Like the ELF linker merging is only performed at `-O1` and above.
This fixes part of https://bugs.llvm.org/show_bug.cgi?id=48828,
although crucially it doesn't not currently support debug sections
because they are not represented by data segments (they are custom
sections)
Differential Revision: https://reviews.llvm.org/D97657
This untangles the MCContext and the MCObjectFileInfo. There is a circular
dependency between MCContext and MCObjectFileInfo. Currently this dependency
also exists during construction: You can't contruct a MOFI without a MCContext
without constructing the MCContext with a dummy version of that MOFI first.
This removes this dependency during construction. In a perfect world,
MCObjectFileInfo wouldn't depend on MCContext at all, but only be stored in the
MCContext, like other MC information. This is future work.
This also shifts/adds more information to the MCContext making it more
available to the different targets. Namely:
- TargetTriple
- ObjectFileType
- SubtargetInfo
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D101462
- As per the HLASM support we are providing, i.e. support only for the first parameter of the inline asm block, only pertaining to Z machine instructions defined in LLVM, character literals and string literals are not supported (see Figure 4 - https://www-01.ibm.com/servers/resourcelink/svc00100.nsf/pages/zOSV2R3sc264940/$file/asmr1023.pdf for more information)
- This patch explicitly rejects the usage of char literals and string literals (for example "abc 'a'") when the relevant field is set
- This is achieved by introducing a field called `LexHLASMStrings` in MCAsmLexer similar to `LexMasmStrings`
Reviewed By: abhina.sreeskantharajan, Kai
Differential Revision: https://reviews.llvm.org/D101660
- This patch attempts to implement the location counter syntax (*) for the HLASM variant for PC-relative instructions.
- In the HLASM variant, for purely constant relocatable values, we expect a * token preceding it, with special support for " *" which is parsed as "<pc-rel-insn 0>"
- For combinations of absolute values and relocatable values, we don't expect the "*" preceding the token.
When you have a " * " what’s accepted is:
```
*<space>.*{.*} -> <pc-rel-insn> 0
*[+|-][constant-value] -> <pc-rel-insn> [+|-]constant-value
```
When you don’t have a " * " what’s accepted is:
```
brasl 1,func is allowed (MCSymbolRef type)
brasl 1,func+4 is allowed (MCBinary type)
brasl 1,4+func is allowed (MCBinary type)
brasl 1,-4+func is allowed (MCBinary type)
brasl 1,func-4 is allowed (MCBinary type)
brasl 1,*func is not allowed (* cannot be used for non-MCConstantExprs)
brasl 1,*+func is not allowed (* cannot be used for non-MCConstantExprs)
brasl 1,*+func+4 is not allowed (* cannot be used for non-MCConstantExprs)
brasl 1,*+4+func is not allowed (* cannot be used for non-MCConstantExprs)
brasl 1,*-4+8+func is not allowed (* cannot be used for non-MCConstantExprs)
```
Reviewed By: Kai
Differential Revision: https://reviews.llvm.org/D100987
- Currently, the "." (Dot) character, when not identifying an Identifier or a Constant, refers to the current PC (Program Counter)
- However, in z/OS, for the HLASM dialect, it strictly accepts only the "*" as the current PC (Support for this will be put up in a follow-up patch)
- The changes in this patch allow individual platforms to choose whether they would like to use the "." (Dot) character as a marker for the current PC or not.
- It is achieved by introducing a new field in MCAsmInfo.h called `DotIsPC` (similar to `DollarIsPC`)
Reviewed By: abhina.sreeskantharajan
Differential Revision: https://reviews.llvm.org/D100975
- Previously, https://reviews.llvm.org/D99889 changed the framework in the AsmLexer to treat special tokens, if they occur at the start of the string, as Identifiers.
- These are used by the MASM Parser implementation in LLVM, and we can extend some of the changes made in the previous patch to SystemZ.
- In SystemZ, the special "tokens" referred to here are "_", "$", "@", "#". [_|$|@|#] are already supported as "part" of an Identifier.
- The changes in this patch ensure that these special tokens, when they occur at the start of the Identifier, are treated as Identifiers.
Reviewed By: abhina.sreeskantharajan
Differential Revision: https://reviews.llvm.org/D100959
- Previously, https://reviews.llvm.org/D72680 introduced a new attribute called `AllowSymbolAtNameStart` (in relation to the MAsmParser changes) in `MCAsmInfo.h` which (according to the comment in the header) allows the following behaviour:
```
/// This is true if the assembler allows $ @ ? characters at the start of
/// symbol names. Defaults to false.
```
- However, the usage of this field in AsmLexer.cpp doesn't seem completely accurate* for a couple of reasons.
```
default:
if (MAI.doesAllowSymbolAtNameStart()) {
// Handle Microsoft-style identifier: [a-zA-Z_$.@?][a-zA-Z0-9_$.@#?]*
if (!isDigit(CurChar) &&
isIdentifierChar(CurChar, MAI.doesAllowAtInName(),
AllowHashInIdentifier))
return LexIdentifier();
}
```
1. The Dollar and At tokens, when occurring at the start of the string, are treated as separate tokens (AsmToken::Dollar and AsmToken::At respectively) and not lexed as an Identifier.
2. I'm not too sure why `MAI.doesAllowAtInName()` is used when `AllowAtInIdentifier` could be used. For X86 platforms, afaict, this shouldn't be an issue, since the `CommentString` attribute isn't "@". (alternatively the call to the setter can be set anywhere else as needed). The `AllowAtInName` does have an additional important meaning, but in the context of AsmLexer, shouldn't mean anything different compared to `AllowAtInIdentifier`
My proposal is the following:
- Introduce 3 new fields called `AllowQuestionTokenAtStartOfString`, `AllowDollarTokenAtStartOfString` and `AllowAtTokenAtStartOfString` in MCAsmInfo.h which will encapsulate the previously documented behaviour of "allowing $, @, ? characters at the start of symbol names")
- Introduce these fields where "$", "@" are lexed, and treat them as identifiers depending on whether `Allow[Dollar|At]TokenAtStartOfString` is set.
- For the sole case of "?", append it to the existing logic for treating a "default" token as an Identifier.
z/OS (HLASM) will also make use of some of these fields in follow up patches.
completely accurate* - This was based on the comments and the intended behaviour the code. I might have completely misinterpreted it, and if that is the case my sincere apologies. We can close this patch if necessary, if there are no changes to be made :)
Depends on https://reviews.llvm.org/D99374
Reviewed By: Jonathan.Crowther
Differential Revision: https://reviews.llvm.org/D99889
- Add support for HLASM style integers. These are the decimal integers [0-9].
- HLASM does not support the additional prefixed integers like, `0b`, `0x`, octal integers and Masm style integers.
- To achieve this, a field `LexHLASMStyleIntegers` (similar to the `LexMasmStyleIntegers` field) is introduced in `MCAsmLexer.h` as well as a corresponding setter.
Note: This field could also go into MCAsmInfo.h. I used the previous precedent set by the `LexMasmIntegers` field.
Depends on https://reviews.llvm.org/D99286
Reviewed By: epastor
Differential Revision: https://reviews.llvm.org/D99374
- Currently, MCAsmInfo provides a CommentString attribute, that various targets can set, so that the AsmLexer can appropriately lex a string as a comment based on the set value of the attribute.
- However, AsmLexer also supports a few additional comment syntaxes, in addition to what's specified as a CommentString attribute. This includes regular C-style block comments (/* ... */), regular C-style line comments (// .... ) and #. While I'm not sure as to why this behaviour exists, I am assuming it does to maintain backward compatibility with GNU AS (see https://sourceware.org/binutils/docs/as/Comments.html#Comments for reference)
For example:
Consider a target which sets the CommentString attribute to '*'.
The following strings are all lexed as comments.
```
"# abc" -> comment
"// abc" -> comment
"/* abc */ -> comment
"* abc" -> comment
```
- In HLASM however, only "*" is accepted as a comment string, and nothing else.
- To achieve this, an additional attribute (`AllowAdditionalComments`) has been added to MCAsmInfo. If this attribute is set to false, then only the string specified by the CommentString attribute is used as a possible comment string to be lexed by the AsmLexer. The regular C-style block comments, line comments and "#" are disabled. As a final note, "#" will still be treated as a comment, if the CommentString attribute is set to "#".
Depends on https://reviews.llvm.org/D99277
Reviewed By: abhina.sreeskantharajan, myiwanch
Differential Revision: https://reviews.llvm.org/D99286
The GNU AS manual states the following about single-character constants enclosed within single quotes:
> Some backslash escapes apply to characters, \b, \f, \n, \r, \t, and \" with the same meaning as for strings, plus \' for a single quote.
Add two more characters to the switch handling this case to match GAS behaviour, plus a test to make sure nothing regresses.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D99609
Problem:
On SystemZ we need to open text files in text mode. On Windows, files opened in text mode adds a CRLF '\r\n' which may not be desirable.
Solution:
This patch adds two new flags
- OF_CRLF which indicates that CRLF translation is used.
- OF_TextWithCRLF = OF_Text | OF_CRLF indicates that the file is text and uses CRLF translation.
Developers should now use either the OF_Text or OF_TextWithCRLF for text files and OF_None for binary files. If the developer doesn't want carriage returns on Windows, they should use OF_Text, if they do want carriage returns on Windows, they should use OF_TextWithCRLF.
So this is the behaviour per platform with my patch:
z/OS:
OF_None: open in binary mode
OF_Text : open in text mode
OF_TextWithCRLF: open in text mode
Windows:
OF_None: open file with no carriage return
OF_Text: open file with no carriage return
OF_TextWithCRLF: open file with carriage return
The Major change is in llvm/lib/Support/Windows/Path.inc to only set text mode if the OF_CRLF is set.
```
if (Flags & OF_CRLF)
CrtOpenFlags |= _O_TEXT;
```
These following files are the ones that still use OF_Text which I left unchanged. I modified all these except raw_ostream.cpp in recent patches so I know these were previously in Binary mode on Windows.
./llvm/lib/Support/raw_ostream.cpp
./llvm/lib/TableGen/Main.cpp
./llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
./llvm/unittests/Support/Path.cpp
./clang/lib/StaticAnalyzer/Core/HTMLDiagnostics.cpp
./clang/lib/Frontend/CompilerInstance.cpp
./clang/lib/Driver/Driver.cpp
./clang/lib/Driver/ToolChains/Clang.cpp
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D99426
These look like $00A0cf for hex and %001010101 for binary. They are used in Motorola assembly syntax.
Differential Revision: https://reviews.llvm.org/D98519
Define -fatal-warnings to make warnings fatal, and accept /WX as an ML.EXE compatible alias for it.
Also make sure that if Warning() returns true, we always treat it as an error.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D92504
Make variables and text-macro references case-insensitive, to match ml.exe.
Also improve error handling for text-macro expansion.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D92503
- This patch adds in support to accept the "#" character as part of an Identifier.
- This support is needed especially for the HLASM dialect since "#" is treated as part of the valid "Alphabet" range
- The way this is done is by making use of the previous precedent set by the `AllowAtInIdentifier` field in `MCAsmLexer.h`. A new field called `AllowHashInIdentifier` is introduced.
- The static function `IsIdentifierChar` is also updated to accept the `#` character if the `AllowHashInIdentifier` field is set to true.
Note: The field introduced in `MCAsmLexer.h` could very well be moved to `MCAsmInfo.h`. I'm not opposed to it. I decided to put it in `MCAsmLexer` since there seems to be some sort of precedent already with `AllowAtInIdentifier`.
Reviewed By: abhina.sreeskantharajan, nickdesaulniers, MaskRay
Differential Revision: https://reviews.llvm.org/D99277