Commit Graph

784 Commits

Author SHA1 Message Date
Abhina Sreeskantharajan 82b3e28e83 [SystemZ][z/OS][Windows] Add new OF_TextWithCRLF flag and use this flag instead of OF_Text
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
2021-04-06 07:23:31 -04:00
Yevgeny Rouban 39e3e3aa51 [NewPM] Redesign of PreserveCFG Checker
The reason for the NewPM redesign is described in the commit
  cba3e783389a: [NewPM] Disable PreservedCFGChecker ...

The checker introduces an internal custom CFG analysis that tracks
current up-to date CFG snapshot. The analysis is invalidated along
any other CFG related analysis (the key is CFGAnalyses). If the CFG
analysis is not invalidated at a functional pass exit then the checker
asserts that the CFG snapshot taken from this analysis is equals to
a snapshot of the current CFG.

Along the way:
- the function CFG::printDiff() is simplified by removing function
  name calculation. The name is printed by the caller;
- fixed CFG invalidated condition (see CFG::invalidate());
- StandardInstrumentations::registerCallbacks() gets additional
  optional parameter of type FunctionAnalysisManager*, which is
  needed by the checker to get the custom CFG analysis;
- several PM related tests updated to explicitly set
  -verify-cfg-preserved=1 as they need.

This patch is safe to land as the CFGChecker is left switched off
(the options -verify-cfg-preserved is false by default). It will be
switched on by a separate patch to minimize possible reverts.

Reviewed By: skatkov, kuhar

Differential Revision: https://reviews.llvm.org/D91327
2021-04-06 12:35:49 +07:00
Wael Yehia 563cdeaafd [LTO][Legacy] Decouple option parsing from LTOCodeGenerator
in this patch we add a new libLTO API to specify debug options independent of an lto_code_gen_t.
This allows clients to pass codegen flags (through libLTO) which otherwise today are ignored.

Reviewed By: steven_wu

Differential Revision: https://reviews.llvm.org/D92611
2021-03-31 16:43:26 +00:00
Wei Mi d535a05ca1 [ThinLTO] During module importing, close one source module before open
another one for distributed mode.

Currently during module importing, ThinLTO opens all the source modules,
collect functions to be imported and append them to the destination module,
then leave all the modules open through out the lto backend pipeline. This
patch refactors it in the way that one source module will be closed before
another source module is opened. All the source modules will be closed after
importing phase is done. It will save some amount of memory when there are
many source modules to be imported.

Note that this patch only changes the distributed thinlto mode. For in
process thinlto mode, one source module is shared acorss different thinlto
backend threads so it is not changed in this patch.

Differential Revision: https://reviews.llvm.org/D99554
2021-03-30 14:37:29 -07:00
Abhina Sreeskantharajan c83cd8feef [NFC] Reordering parameters in getFile and getFileOrSTDIN
In future patches I will be setting the IsText parameter frequently so I will refactor the args to be in the following order. I have removed the FileSize parameter because it is never used.

```
  static ErrorOr<std::unique_ptr<MemoryBuffer>>
  getFile(const Twine &Filename, bool IsText = false,
          bool RequiresNullTerminator = true, bool IsVolatile = false);

  static ErrorOr<std::unique_ptr<MemoryBuffer>>
  getFileOrSTDIN(const Twine &Filename, bool IsText = false,
                 bool RequiresNullTerminator = true);

 static ErrorOr<std::unique_ptr<MB>>
 getFileAux(const Twine &Filename, uint64_t MapSize, uint64_t Offset,
            bool IsText, bool RequiresNullTerminator, bool IsVolatile);

  static ErrorOr<std::unique_ptr<WritableMemoryBuffer>>
  getFile(const Twine &Filename, bool IsVolatile = false);
```

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D99182
2021-03-25 09:47:49 -04:00
Yuanfang Chen b4a8c0ebb6 [LTO][MC] Discard non-prevailing defined symbols in module-level assembly
This is the alternative approach to D96931.

In LTO, for each module with inlineasm block, prepend directive ".lto_discard <sym>, <sym>*" to the beginning of the inline
asm.  ".lto_discard" is both a module inlineasm block marker and (optionally) provides a list of symbols to be discarded.

In MC while emitting for inlineasm, discard symbol binding & symbol
definitions according to ".lto_disard".

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D98762
2021-03-18 15:33:42 -07:00
Wael Yehia be646e3148 llvm-lto: default Relocation Model should be selected by the TargetMachine.
Right now, the createTargetMachine function in LTOBackend.cpp (used by llvm-lto, and other components) selects the default Relocation Model when none is specified in the module.
Other components (such as opt and llc) that construct a TargetMachine delegate the decision on the default value to the polymorphic TargetMachine's constructor.

This commit aligns llvm-lto with other components.

Reviewed By: daltenty, fhahn

Differential Revision: https://reviews.llvm.org/D97507
2021-03-10 17:31:26 -05:00
Fangrui Song 584cb67d2d [IRSymTab] Set FB_used on llvm.compiler.used symbols
IR symbol table does not parse inline asm. A symbol only referenced by inline
asm is not in the IR symbol table, so LTO does not know that the definition (in
another translation unit) is referenced and may internalize it, even if that
definition has `__attribute__((used))` (which lowers to `llvm.compiler.used` on
ELF targets since D97446).

```
// cabac.c
__attribute__((used)) const uint8_t ff_h264_cabac_tables[...] = {...};

// h264_cabac.c
  asm("lea ff_h264_cabac_tables(%rip), %0" : ...);
```

`__attribute__((used))` is the recommended way to tell the compiler there may
be inline asm references, so the usage is perfectly fine. This patch
conservatively sets the `FB_used` bit on `llvm.compiler.used` symbols to work
around the IR symbol table limitation. Note: before D97446, Clang never emitted
symbols in the `llvm.compiler.used` list, so this change does not punish any
Clang emitted global object.

Without the patch, `ff_h264_cabac_tables` may be assigned to a non-external
partition and get internalized. Then we will get a linker error because the
`cabac.c` definition is not exposed.

Differential Revision: https://reviews.llvm.org/D97755
2021-03-03 16:22:30 -08:00
Benjamin Kramer 715dc556b7 [lto] Enable new PM when the PM config is non-empty
This restores the behavior before 964f8103c5, which broke 2 tests:
  LLVM :: tools/llvm-lto2/X86/pipeline.ll
  lld :: ELF/lto/ltopasses-custom.ll
2021-02-15 20:49:09 +01:00
Florian Hahn c70737ba1d Recommit "[LTO] Use lto::backend for code generation."
This version of the patch includes a fix for the cfi failures.

(undoes the revert commit 7db390cc77)

It also undoes reverts of follow-up patches that also needed reverting
originally:

  * [LTO] Add option enable NewPM with LTOCodeGenerator.
    (undoes revert commit 0a17664b47)

  * [LTOCodeGenerator] Use lto::Config for options (NFC)."
    (undoes revert commit b0a8e41cff)
2021-02-15 10:05:42 +00:00
Wei Wang 80dc0661bd [LTO] Perform DSOLocal propagation in combined index
Perform DSOLocal propagation within summary list of every GV. This
avoids the repeated query of this information during function
importing.

Differential Revision: https://reviews.llvm.org/D96398
2021-02-12 22:58:26 -08:00
Arthur Eubanks 964f8103c5 [NFC] Combine runNewPMPasses() and runNewPMCustomPasses()
I've already witnessed two separate changes missing runNewPMPasses()
because runNewPMCustomPasses() is so similar.

This cleans up some duplicated code.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D96553
2021-02-12 16:44:52 -08:00
Arthur Eubanks 8334cdde2e [NFC] Don't pass redundant arguments
Some parameters were already part of the Config passed in.
2021-02-10 22:06:49 -08:00
Florian Hahn 7db390cc77
Revert "[LTO] Use lto::backend for code generation."
This reverts commit 6a59f05606, because
it is causing failures on green dragon.
2021-02-03 22:49:30 +00:00
Florian Hahn 0a17664b47
Revert "[LTO] Add option enable NewPM with LTOCodeGenerator."
This reverts commit 7a6a2cc81a because
it is causing failures on green dragon.
2021-02-03 22:49:20 +00:00
Florian Hahn b0a8e41cff
Revert "[LTOCodeGenerator] Use lto::Config for options (NFC)."
This reverts commit 0d487cf87a because
it is causing failures on green dragon.
2021-02-03 22:48:54 +00:00
Florian Hahn 0d487cf87a
[LTOCodeGenerator] Use lto::Config for options (NFC).
This patch removes some options that have been duplicated in
LTOCodeGenerator and instead use lto::Config directly to manage the
options.

This is a cleanup after 6a59f05606.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D95738
2021-01-31 19:08:07 +00:00
Florian Hahn 7a6a2cc81a [LTO] Add option enable NewPM with LTOCodeGenerator.
This patch adds an option to enable the new pass manager in
LTOCodeGenerator. It also updates a few tests with legacy PM specific
tests, which started failing after 6a59f05606 when
LLVM_ENABLE_NEW_PASS_MANAGER=true.
2021-01-30 11:54:20 +00:00
Florian Hahn 6a59f05606 [LTO] Use lto::backend for code generation.
This patch updates LTOCodeGenerator to use the utilities provided by
LTOBackend to run middle-end optimizations and backend code generation.

This is a first step towards unifying the code used by libLTO's C API
and the newer, C++ interface (see PR41541).

The immediate motivation is to allow using the new pass manager when
doing LTO using libLTO's C API, which is used on Darwin, among others.

With the changes, there are no codegen/stats differences when building
MultiSource/SPEC2000/SPEC2006 on Darwin X86 with LTO, compared
to without the patch.

Reviewed By: steven_wu

Differential Revision: https://reviews.llvm.org/D94487
2021-01-30 10:09:55 +00:00
Florian Hahn f3a710cade [LTO] Update splitCodeGen to take a reference to the module. (NFC)
splitCodeGen does not need to take ownership of the module, as it
currently clones the original module for each split operation.

There is an ~4 year old fixme to change that, but until this is
addressed, the function can just take a reference to the module.

This makes the transition of LTOCodeGenerator to use LTOBackend a bit
easier, because under some circumstances, LTOCodeGenerator needs to
write the original module back after codegen.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D95222
2021-01-29 11:53:11 +00:00
Teresa Johnson 1487747e99 [LTO] Prevent devirtualization for symbols dynamically exported
Identify dynamically exported symbols (--export-dynamic[-symbol=],
--dynamic-list=, or definitions needed to preempt shared objects) and
prevent their LTO visibility from being upgraded.
This helps avoid use of whole program devirtualization when there may
be overrides in dynamic libraries.

Differential Revision: https://reviews.llvm.org/D91583
2021-01-27 15:54:13 -08:00
Fangrui Song 54fb3ca96e [ThinLTO] Add Visibility bits to GlobalValueSummary::GVFlags
Imported functions and variable get the visibility from the module supplying the
definition.  However, non-imported definitions do not get the visibility from
(ELF) the most constraining visibility among all modules (Mach-O) the visibility
of the prevailing definition.

This patch

* adds visibility bits to GlobalValueSummary::GVFlags
* computes the result visibility and propagates it to all definitions

Protected/hidden can imply dso_local which can enable some optimizations (this
is stronger than GVFlags::DSOLocal because the implied dso_local can be
leveraged for ELF -shared while default visibility dso_local has to be cleared
for ELF -shared).

Note: we don't have summaries for declarations, so for ELF if a declaration has
the most constraining visibility, the result visibility may not be that one.

Differential Revision: https://reviews.llvm.org/D92900
2021-01-27 10:43:51 -08:00
Florian Hahn f959d8195d
[LTO] Move DisableVerify setting to LTOCodeGenerator class (NFC).
To simplify the transition to using LTOBackend, move DisableVerify to
the LTOCodeGenerator class, like most/all other options.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D95223
2021-01-24 14:14:40 +00:00
Florian Hahn 08dbcc14e2
[LTO] Store target attributes as vector of strings (NFC).
The target features are obtained as a list of features/attributes.
Instead of storing them in a single string, store the vector. This
matches lto::Config's behavior and simplifies the transition to
lto::backend().

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D95224
2021-01-23 12:11:58 +00:00
Florian Hahn 2a8cbdd830
[LTO] Add support for existing Config::Freestanding option.
lto::Config has a field to control whether the build is "freestanding"
(no builtins) or not, but it is not hooked up to the code actually
running the passes.

This patch adds support for the flag to both the code that runs
optimization with the new and old pass managers, by explicitly adding a
TargetLibraryInfo instance. If Freestanding is true, all library functions
are disabled.

Reviewed By: steven_wu

Differential Revision: https://reviews.llvm.org/D94630
2021-01-22 13:45:39 +00:00
Jez Ng 697f4e429b [lld-macho] Run ObjCContractPass during LTO
Run the ObjCARCContractPass during LTO. The legacy LTO backend (under
LTO/ThinLTOCodeGenerator.cpp) already does this; this diff just adds that
behavior to the new LTO backend. Without that pass, the objc.clang.arc.use
intrinsic will get passed to the instruction selector, which doesn't know how to
handle it.

In order to test both the new and old pass managers, I've also added support for
the `--[no-]lto-legacy-pass-manager` flags.

P.S. Not sure if the ordering of the pass within the pipeline matters...

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D94547
2021-01-20 14:21:32 -05:00
Florian Hahn bca16e2fbb
[LTO] Remove options to disable inlining, vectorization & GVNLoadPRE.
This patch removes some ancient options as a clean-up before moving
code-gen to use LTOBackend in D94487.

I think it would preferable to remove those ancient options, because

  1. There are no corresponding options in LTOBackend based tools,
  2. There are no unit tests for them,
  3. They are not passed through by Clang,
  4. At least for GNVLoadPRE, users could just use GVN's `enable-load-pre`.

Alternatively we could add support for those options to lto::Config &
co, but I think it would be better to remove them, unless they are
actually used in practice.

Reviewed By: steven_wu, tejohnson

Differential Revision: https://reviews.llvm.org/D94783
2021-01-16 16:29:15 +00:00
Florian Hahn 4bb11b3eaf
[LTO] Expose opt() in LTOBackend (NFC).
Exposing opt() which runs middle-end LTO optimzation allows re-using it
in LTOCodeGenerator.

Reviewed By: steven_wu

Differential Revision: https://reviews.llvm.org/D94486
2021-01-14 09:53:41 +00:00
Florian Hahn f638c2eb4e [LTO] Replace anonymous namespace with static functions (NFC).
Only class declarations should be inside anonymous namespaces
(https://llvm.org/docs/CodingStandards.html#anonymous-namespaces)

Instead of using a anonymous namespace, just mark the functions in it as
static (some of them already were).

This simplifies the diff for D94486.
2021-01-13 09:32:15 +00:00
dfukalov 9ed8e0caab [NFC] Reduce include files dependency and AA header cleanup (part 2).
Continuing work started in https://reviews.llvm.org/D92489:

Removed a bunch of includes from "AliasAnalysis.h" and "LoopPassManager.h".

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D92852
2020-12-17 14:04:48 +03:00
Ahmed Bougacha f77c948d56 [Triple][MachO] Define "arm64e", an AArch64 subarch for Pointer Auth.
This also teaches MachO writers/readers about the MachO cpu subtype,
beyond the minimal subtype reader support present at the moment.

This also defines a preprocessor macro to allow users to distinguish
__arm64__ from __arm64e__.

arm64e defaults to an "apple-a12" CPU, which supports v8.3a, allowing
pointer-authentication codegen.
It also currently defaults to ios14 and macos11.

Differential Revision: https://reviews.llvm.org/D87095
2020-12-03 07:53:59 -08:00
dfukalov 2ce38b3f03 [NFC] Reduce include files dependency.
1. Removed #include "...AliasAnalysis.h" in other headers and modules.
2. Cleaned up includes in AliasAnalysis.h.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D92489
2020-12-03 18:25:05 +03:00
Arthur Eubanks 26d3aaeb3a [LTO][NewPM] Run verifier when doing LTO
This matches the legacy PM.

Reviewed By: ychen

Differential Revision: https://reviews.llvm.org/D92138
2020-12-01 10:14:53 -08:00
Wei Wang 3acda91742 [Remarks][1/2] Expand remarks hotness threshold option support in more tools
This is the #1 of 2 changes that make remarks hotness threshold option
available in more tools. The changes also allow the threshold to sync with
hotness threshold from profile summary with special value 'auto'.

This change modifies the interface of lto::setupLLVMOptimizationRemarks() to
accept remarks hotness threshold. Update all the tools that use it with remarks
hotness threshold options:

* lld: '--opt-remarks-hotness-threshold='
* llvm-lto2: '--pass-remarks-hotness-threshold='
* llvm-lto: '--lto-pass-remarks-hotness-threshold='
* gold plugin: '-plugin-opt=opt-remarks-hotness-threshold='

Differential Revision: https://reviews.llvm.org/D85809
2020-11-30 21:55:49 -08:00
Ella Ma 1756d67934 [llvm][clang][mlir] Add checks for the return values from Target::createXXX to prevent protential null deref
All these potential null pointer dereferences are reported by my static analyzer for null smart pointer dereferences, which has a different implementation from `alpha.cplusplus.SmartPtr`.

The checked pointers in this patch are initialized by Target::createXXX functions. When the creator function pointer is not correctly set, a null pointer will be returned, or the creator function may originally return a null pointer.

Some of them may not make sense as they may be checked before entering the function, but I fixed them all in this patch. I submit this fix because 1) similar checks are found in some other places in the LLVM codebase for the same return value of the function; and, 2) some of the pointers are dereferenced before they are checked, which may definitely trigger a null pointer dereference if the return value is nullptr.

Reviewed By: tejohnson, MaskRay, jpienaar

Differential Revision: https://reviews.llvm.org/D91410
2020-11-21 21:04:12 -08:00
serge-sans-paille 9218ff50f9 llvmbuildectomy - replace llvm-build by plain cmake
No longer rely on an external tool to build the llvm component layout.

Instead, leverage the existing `add_llvm_componentlibrary` cmake function and
introduce `add_llvm_component_group` to accurately describe component behavior.

These function store extra properties in the created targets. These properties
are processed once all components are defined to resolve library dependencies
and produce the header expected by llvm-config.

Differential Revision: https://reviews.llvm.org/D90848
2020-11-13 10:35:24 +01:00
Arthur Eubanks 2e31727a88 [NFC] Clean up PassBuilder
Make DebugLogging a member variable so that users of PassBuilder don't
need to pass it around so much.

Move call to TargetMachine::registerPassBuilderCallbacks() within
PassBuilder so users don't need to remember to call it.

Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D90437
2020-10-30 10:03:59 -07:00
Mircea Trofin 735ab4be35 [ThinLTO] Fix .llvmcmd emission
llvm::EmbedBitcodeInModule needs (what used to be called) EmbedMarker
set, in order to emit .llvmcmd. EmbedMarker is really about embedding the
command line, so renamed the parameter accordingly, too.

This was not caught at test because the check-prefix was incorrect, but
FileCheck does not report that when multiple prefixes are provided. A
separate patch will address that.

Differential Revision: https://reviews.llvm.org/D90278
2020-10-28 17:45:30 -07:00
Mircea Trofin 6fa35541a0 [NFC][ThinLTO] Change command line passing to EmbedBitcodeInModule
Changing to pass by ref - less null checks to worry about.

Differential Revision: https://reviews.llvm.org/D90330
2020-10-28 12:33:39 -07:00
Alexandre Ganea 617d64f6c5 Re-land [ThinLTO] Re-order modules for optimal multi-threaded processing
This reverts 9b5b305023 and fixes the unwanted re-ordering when generating ThinLTO indexes.

The goal of this patch is to better balance thread utilization during ThinLTO in-process linking (in llvm-lto2 or in LLD). Before this patch, large modules would often be scheduled late during execution, taking a long time to complete, thus starving the thread pool.

We now sort modules in descending order, based on each module's bitcode size, so that larger modules are processed first. By doing so, smaller modules have a better chance to keep the thread pool active, and thus avoid starvation when the bitcode compilation is almost complete.

In our case (on dual Intel Xeon Gold 6140, Windows 10 version 2004, two-stage build), this saves 15 sec when linking `clang.exe` with LLD & -flto=thin, /opt:lldltojobs=all, no ThinLTO cache, -DLLVM_INTEGRATED_CRT_ALLOC=d:\git\rpmalloc.

Before patch: 100 sec
After patch: 85 sec

Inspired by the work done by David Callahan in D60495.

Differential Revision: https://reviews.llvm.org/D87966
2020-10-13 21:54:15 -04:00
Jordan Rupprecht 9b5b305023 Temporarily revert "[ThinLTO] Re-order modules for optimal multi-threaded processing"
This reverts commit 6537004913. This is causing test failures internally, and while a few of the cases turned out to be bad user code (relying on a specific order of static initialization across translation units), some cases are less clear. Temporarily reverting for now, and Teresa is going to follow up with more details.
2020-10-09 14:36:20 -07:00
Mircea Trofin cf112382dd [ThinLTO] Option to bypass function importing.
This completes the circle, complementing -lto-embed-bitcode
(specifically, post-merge-pre-opt). Using -thinlto-assume-merged skips
function importing. The index file is still needed for the other data it
contains.

Differential Revision: https://reviews.llvm.org/D87949
2020-09-22 13:12:11 -07:00
Alexandre Ganea 6537004913 [ThinLTO] Re-order modules for optimal multi-threaded processing
Re-use an optimizition from the old LTO API (used by ld64).
This sorts modules in ascending order, based on bitcode size, so that larger modules are processed first. This allows for smaller modules to be process last, and better fill free threads 'slots', and thusly allow for better multi-thread load balancing.

In our case (on dual Intel Xeon Gold 6140, Windows 10 version 2004, two-stage build), this saves 15 sec when linking `clang.exe` with LLD & `-flto=thin`, `/opt:lldltojobs=all`, no ThinLTO cache, -DLLVM_INTEGRATED_CRT_ALLOC=d:\git\rpmalloc.

Before patch: 102 sec
After patch: 85 sec

Inspired by the work done by David Callahan in D60495.

Differential Revision: https://reviews.llvm.org/D87966
2020-09-22 11:25:59 -04:00
Mircea Trofin 61fc10d6a5 [ThinLTO] add post-thinlto-merge option to -lto-embed-bitcode
This will embed bitcode after (Thin)LTO merge, but before optimizations.
In the case the thinlto backend is called from clang, the .llvmcmd
section is also produced. Doing so in the case where the caller is the
linker doesn't yet have a motivation, and would require plumbing through
command line args.

Differential Revision: https://reviews.llvm.org/D87636
2020-09-15 15:56:11 -07:00
Mircea Trofin 9a2bab5ea2 [ThinLTO] Make -lto-embed-bitcode an enum
The current behavior of -lto-embed-bitcode is not quite the same as that
of -fembed-bitcode. While both populate .llvmbc with bitcode, the latter
populates it with pre-optimized bitcode(*), while the former with
post-optimized. The scenarios driving them are different - the latter's
goal is to allow re-compilation, while the former, IIUC, is execution.

I plan to add a third mode for thinlto cases, closely-related to
-fembed-bitcode's scenario: adding the bitcode pre-optimization, but
post-merging. This would allow re-compilation without requiring the
other .bc files that were merged (akin to how -fembed-bitcode allows
recompilation without all the .h files)

The third mode can't co-exist with the current -lto-embed-bitcode mode,
because the latter would overwrite it. For clarity, we change
-lto-embed-bitcode to be an enum.

(*) That's the compiler semantics. The driver splits compilation in 2
phases, so if -fembed-bitcode is given to the driver, the .llvmbc is
optimized bitcode; if the option is passed to the compiler (after -cc1),
the section is pre-optimized.

Differential Revision: https://reviews.llvm.org/D87477
2020-09-11 13:24:54 -07:00
Mircea Trofin e543708e5e [NFC][ThinLTO] Let llvm::EmbedBitcodeInModule handle serialization.
llvm::EmbedBitcodeInModule handles serializing the passed-in module, if
the provided MemoryBufferRef is invalid. This is already the path taken
in one of the uses of the API - clang::EmbedBitcode, when called from
BackendConsumer::HandleTranslationUnit - so might as well do the same
here and reduce (by very little) code duplication.

The only difference this patch introduces is that the serialization happens
with ShouldPreserveUseListOrder set to true.

Differential Revision: https://reviews.llvm.org/D87339
2020-09-10 10:25:00 -07:00
Mircea Trofin 4013bab9c4 [NFC][ThinLTO] EmbedBitcodeSection doesn't need the Config
Instead, passing in the command line options, initialized to nullptr. In
an upcoming patch, we can then use the parameter to pass actual command
line options.

Differential Revision: https://reviews.llvm.org/D87336
2020-09-08 17:14:44 -07:00
Steven Wu 97866b8de8 [ThinLTO][Legacy] Fix StringRef assertion from ThinLTO bots
This is a presumed fix for FireFox thinLTO bot fix which hits assertion
failure for invalid index when access StringRef. Techinically, `IRName`
in the symtab should not be empty string for the entries we cared about
but this will help to fix the bot before more information can be
provided. Otherwise, NFCI.
2020-09-04 12:30:09 -07:00
Steven Wu 476ca33089 [LTO] Don't apply LTOPostLink module flag during writeMergedModule
For `ld64` which uses legacy LTOCodeGenerator, it relies on
writeMergedModule to perform `ld -r` (generates a linked object file).
If all the inputs to `ld -r` is fullLTO bitcode, `ld64` will linked the
bitcode module, internalize all the symbols and write out another
fullLTO bitcode object file. This bitcode file doesn't have all the
bitcode inputs and it should not have LTOPostLink module flag. It will
also cause error when this bitcode object file is linked with other LTO
object file.
Fix the issue by not applying LTOPostLink flag during writeMergedModule
function. The flag should only be added when all the bitcode are linked
and ready to be optimized.

rdar://problem/58462798

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D84789
2020-08-26 11:17:45 -07:00
Steven Wu 34b289b6db [ThinLTO][Legacy] Compute PreservedGUID based on IRName in Symtab
Instead of computing GUID based on some assumption about symbol mangling
rule from IRName to symbol name, lookup the IRName from all the symtabs
from all the input files to see if there are any matching symbols entry
provides the IRName for GUID computation.

rdar://65853754

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D84803
2020-08-26 10:15:00 -07:00