Commit Graph

95 Commits

Author SHA1 Message Date
Teresa Johnson d0aad9f56e [LTO] Constify lto::Config reference passed to backends (NFC)
The lto::Config object saved on the global LTO object should not be
updated by any of the LTO backends. Otherwise we could run into
interference between threads utilizing it. Motivated by some proposed
changes that would have caused it to get modified in the ThinLTO
backends.
2020-01-13 12:26:17 -08:00
Wei Mi 21a4710c67 [ThinLTO] Pass CodeGenOpts like UnrollLoops/VectorizeLoop/VectorizeSLP
down to pass builder in ltobackend.

Currently CodeGenOpts like UnrollLoops/VectorizeLoop/VectorizeSLP in clang
are not passed down to pass builder in ltobackend when new pass manager is
used. This is inconsistent with the behavior when new pass manager is used
and thinlto is not used. Such inconsistency causes slp vectorization pass
not being enabled in ltobackend for O3 + thinlto right now. This patch
fixes that.

Differential Revision: https://reviews.llvm.org/D72386
2020-01-09 21:13:11 -08:00
evgeny ad364956ed [ThinLTO] Show preserved symbols in DOT files
Differential revision: https://reviews.llvm.org/D71608
2019-12-18 18:33:15 +03:00
Teresa Johnson c8e0bb3b2c [LTO] Support for embedding bitcode section during LTO
Summary:
This adds support for embedding bitcode in a binary during LTO. The libLTO gains supports the `-lto-embed-bitcode` flag. The option allows users of the LTO library to embed a bitcode section. For example, LLD can pass the option via `ld.lld -mllvm=-lto-embed-bitcode`.

This feature allows doing something comparable to `clang -c -fembed-bitcode`, but on the (LTO) linker level. Having bitcode alongside native code has many use-cases. To give an example, the MacOS linker can create a `-bitcode_bundle` section containing bitcode. Also, having this feature built into LLVM is an alternative to 3rd party tools such as [[ https://github.com/travitch/whole-program-llvm | wllvm ]] or [[ https://github.com/SRI-CSL/gllvm | gllvm ]]. As with these tools, this feature simplifies creating "whole-program" llvm bitcode files, but in contrast to wllvm/gllvm it does not rely on a specific llvm frontend/driver.

Patch by Josef Eisl <josef.eisl@oracle.com>

Reviewers: #llvm, #clang, rsmith, pcc, alexshap, tejohnson

Reviewed By: tejohnson

Subscribers: tejohnson, mehdi_amini, inglorion, hiraditya, aheejin, steven_wu, dexonsmith, dang, cfe-commits, llvm-commits, #llvm, #clang

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D68213
2019-12-12 12:34:19 -08:00
Taewook Oh 213d8a9f13 [NewPM][PassInstrumentation] IR printing support for (Thin)LTO
Summary: IR printing has not been correctly supported with (Thin)LTO if the new pass manager is enabled. Previously we only get outputs from backend(codegen) passes, as they are still under legacy pass manager even when the new pass manager is enabled. This patch addresses the issue and enables IR printing for optimization passes with new pass manager + (Thin)LTO setting.

Reviewers: fedor.sergeev, philip.pfaffe

Subscribers: mehdi_amini, inglorion, hiraditya, steven_wu, dexonsmith, dang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66253

llvm-svn: 369024
2019-08-15 17:47:44 +00:00
Jonas Devlieghere 0eaee545ee [llvm] Migrate llvm::make_unique to std::make_unique
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

llvm-svn: 369013
2019-08-15 15:54:37 +00:00
Fangrui Song d9b948b6eb Rename F_{None,Text,Append} to OF_{None,Text,Append}. NFC
F_{None,Text,Append} are kept for compatibility since r334221.

llvm-svn: 367800
2019-08-05 05:43:48 +00:00
Francis Visoiu Mistrih 34667519dc [Remarks] Extend -fsave-optimization-record to specify the format
Use -fsave-optimization-record=<format> to specify a different format
than the default, which is YAML.

For now, only YAML is supported.

llvm-svn: 363573
2019-06-17 16:06:00 +00:00
Aaron Puchert e1dc495e63 [Clang] Harmonize Split DWARF options with llc
Summary:
With Split DWARF the resulting object file (then called skeleton CU)
contains the file name of another ("DWO") file with the debug info.
This can be a problem for remote compilation, as it will contain the
name of the file on the compilation server, not on the client.

To use Split DWARF with remote compilation, one needs to either

* make sure only relative paths are used, and mirror the build directory
  structure of the client on the server,
* inject the desired file name on the client directly.

Since llc already supports the latter solution, we're just copying that
over. We allow setting the actual output filename separately from the
value of the DW_AT_[GNU_]dwo_name attribute in the skeleton CU.

Fixes PR40276.

Reviewers: dblaikie, echristo, tejohnson

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D59673

llvm-svn: 363496
2019-06-15 15:38:51 +00:00
Francis Visoiu Mistrih 7a21113ce8 Reland: [Remarks] Refactor optimization remarks setup
* Add a common function to setup opt-remarks
* Rename common options to the same names
* Add error types to distinguish between file errors and regex errors

llvm-svn: 363415
2019-06-14 16:20:51 +00:00
Francis Visoiu Mistrih e4147ea1ef Revert "[Remarks] Refactor optimization remarks setup"
This reverts commit 6e6e3af55b.

This breaks greendragon.

llvm-svn: 363343
2019-06-14 00:05:56 +00:00
Francis Visoiu Mistrih 6e6e3af55b [Remarks] Refactor optimization remarks setup
* Add a common function to setup opt-remarks
* Rename common options to the same names
* Add error types to distinguish between file errors and regex errors

llvm-svn: 363328
2019-06-13 21:46:57 +00:00
Alina Sbirlea 0499a2f961 [NewPassManager] Adding pass tuning options: loop vectorize.
Summary:
Trying to add the plumbing necessary to add tuning options to the new pass manager.
Testing with the flags for loop vectorize.

Reviewers: chandlerc

Subscribers: sanjoy, mehdi_amini, jlebar, steven_wu, dexonsmith, dang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59723

llvm-svn: 358763
2019-04-19 16:11:59 +00:00
Francis Visoiu Mistrih dd42236c6c Reland "[Remarks] Add -foptimization-record-passes to filter remark emission"
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.

This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`

will only emit the remarks coming from the pass `inline`.

This adds:

* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin

Differential Revision: https://reviews.llvm.org/D59268

Original llvm-svn: 355964

llvm-svn: 355984
2019-03-12 21:22:27 +00:00
Francis Visoiu Mistrih 1d6c47ad2b Revert "[Remarks] Add -foptimization-record-passes to filter remark emission"
This reverts commit 20fff32b7d.

llvm-svn: 355976
2019-03-12 20:54:18 +00:00
Francis Visoiu Mistrih 20fff32b7d [Remarks] Add -foptimization-record-passes to filter remark emission
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.

This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`

will only emit the remarks coming from the pass `inline`.

This adds:

* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin

Differential Revision: https://reviews.llvm.org/D59268

llvm-svn: 355964
2019-03-12 20:28:50 +00:00
Rong Xu db29a3a438 [PGO] Context sensitive PGO (part 3)
Part 3 of CSPGO changes (mostly related to PassMananger).

Differential Revision: https://reviews.llvm.org/D54175

llvm-svn: 355330
2019-03-04 20:21:27 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Pirama Arumuga Nainar e61652a384 [LTO] Drop non-prevailing definitions only if linkage is not local or appending
Summary:
This fixes PR 37422

In ELF, non-weak symbols can also be non-prevailing.  In this particular
PR, the __llvm_profile_* symbols are non-prevailing but weren't getting
dropped - causing multiply-defined errors with lld.

Also add a test, strong_non_prevailing.ll, to ensure that multiple
copies of a strong symbol are dropped.

To fix the test regressions exposed by this fix,
- do not mark prevailing copies for symbols with 'appending' linkage.
There's no one prevailing copy for such symbols.
- fix the prevailing version in dead-strip-fulllto.ll
- explicitly pass exported symbols to llvm-lto in fumcimport.ll and
funcimport_var.ll

Reviewers: tejohnson, pcc

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith,
dang, srhines, llvm-commits

Differential Revision: https://reviews.llvm.org/D54125

llvm-svn: 346436
2018-11-08 20:10:07 +00:00
Fedor Sergeev bd6b2138b9 [NewPM] teach -passes= to emit meaningful error messages
All the PassBuilder::parse interfaces now return descriptive StringError
instead of a plain bool. It allows to make -passes/aa-pipeline parsing
errors context-specific and thus less confusing.

TODO: ideally we should also make suggestions for misspelled pass names,
but that requires some extensions to PassBuilder.

Reviewed By: philip.pfaffe, chandlerc
Differential Revision: https://reviews.llvm.org/D53246

llvm-svn: 344685
2018-10-17 10:36:23 +00:00
Fedor Sergeev a01be0f217 Revert "[NewPM] teach -passes= to emit meaningful error messages"
This reverts r344519 due to failures in pipeline-parsing test.

llvm-svn: 344524
2018-10-15 15:36:08 +00:00
Fedor Sergeev 4155a77e98 [NewPM] teach -passes= to emit meaningful error messages
Summary:
All the PassBuilder::parse interfaces now return descriptive StringError
instead of a plain bool. It allows to make -passes/aa-pipeline parsing
errors context-specific and thus less confusing.

TODO: ideally we should also make suggestions for misspelled pass names,
but that requires some extensions to PassBuilder.

Reviewed By: philip.pfaffe, chandlerc
Differential Revision: https://reviews.llvm.org/D53246

llvm-svn: 344519
2018-10-15 15:00:18 +00:00
Richard Smith 6c67662816 Add a flag to remap manglings when reading profile data information.
This can be used to preserve profiling information across codebase
changes that have widespread impact on mangled names, but across which
most profiling data should still be usable. For example, when switching
from libstdc++ to libc++, or from the old libstdc++ ABI to the new ABI,
or even from a 32-bit to a 64-bit build.

The user can provide a remapping file specifying parts of mangled names
that should be treated as equivalent (eg, std::__1 should be treated as
equivalent to std::__cxx11), and profile data will be treated as
applying to a particular function if its name is equivalent to the name
of a function in the profile data under the provided equivalences. See
the documentation change for a description of how this is configured.

Remapping is supported for both sample-based profiling and instruction
profiling. We do not support remapping indirect branch target
information, but all other profile data should be remapped
appropriately.

Support is only added for the new pass manager. If someone wants to also
add support for this for the old pass manager, doing so should be
straightforward.

This is the LLVM side of Clang r344199.

Reviewers: davidxl, tejohnson, dlj, erik.pilkington

Subscribers: mehdi_amini, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D51249

llvm-svn: 344200
2018-10-10 23:13:47 +00:00
Caroline Tice 3dea3f9e0a Pass code-model through Module IR to LTO which will use it.
Currently the code-model does not get saved in the module IR,
so if a code model is specified when compiling with LTO,
it gets lost and is not propagated properly to LTO. This patch,
along with one for the front end, fixes that.

Differential Revision: https://reviews.llvm.org/D52322

llvm-svn: 342760
2018-09-21 18:41:31 +00:00
Teresa Johnson 28023dbed7 [ThinLTO] Enable ThinLTO WholeProgramDevirt and LowerTypeTests in new PM
Summary:
Enable these passes for CFI and WPD in ThinLTO and LTO with the new pass
manager. Add a couple of tests for both PMs based on the clang tests
tools/clang/test/CodeGen/thinlto-distributed-cfi*.ll, but just test
through llvm-lto2 and not with distributed ThinLTO.

Reviewers: pcc

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D49429

llvm-svn: 337461
2018-07-19 14:51:32 +00:00
Peter Collingbourne 3aa30e8062 IRGen: Write .dwo files when -split-dwarf-file is used together with -fthinlto-index.
Differential Revision: https://reviews.llvm.org/D47597

llvm-svn: 333677
2018-05-31 18:25:59 +00:00
Peter Collingbourne 274c4f7ab4 Fix a make_unique ambiguity.
llvm-svn: 332889
2018-05-21 20:56:28 +00:00
Peter Collingbourne c5a9765cea LTO: Replace split dwarf implementation that uses objcopy with one that uses direct emission.
Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47091

llvm-svn: 332884
2018-05-21 20:26:49 +00:00
Peter Collingbourne 9a45114b3c CodeGen: Add a dwo output file argument to addPassesToEmitFile and hook it up to dwo output.
Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47089

llvm-svn: 332881
2018-05-21 20:16:41 +00:00
Teresa Johnson 81d9207317 [LTO] Handle Task=-1 passed to addSaveTemps
Summary:
This change is necessary for D46464, which will pass -1 as the Task
ID for distributed backends, so that the save temps files don't end
up with "4294967295" in their path. For distributed back ends, when -1
is passed, don't append any Task ID.

An existing test (tools/clang/test/CodeGen/thinlto_backend.ll) will
fail without this change after D46464.

Reviewers: pcc

Subscribers: mehdi_amini, inglorion, llvm-commits

Differential Revision: https://reviews.llvm.org/D46488

llvm-svn: 331591
2018-05-05 14:37:20 +00:00
Teresa Johnson 85cc298c1a [ThinLTO] Add support for optimization remarks to thinBackend
Summary:
Support was added to the regular LTO backend, but not thinBackend.
This patch adds that support.

Reviewers: pcc, davide

Subscribers: mehdi_amini, inglorion, llvm-commits

Differential Revision: https://reviews.llvm.org/D46376

llvm-svn: 331481
2018-05-03 20:24:12 +00:00
Yunlian Jiang bd200b9ff6 Enable debug fission for thinLTO linked via gold-plugin
Summary: This enables debug fission on implicit ThinLTO when linked with gold. It will put the .dwo files in a directory specified by user. 

Reviewers: tejohnson, pcc, dblaikie

Reviewed By: pcc

Subscribers: JDevlieghere, mehdi_amini, inglorion

Differential Revision: https://reviews.llvm.org/D44792

llvm-svn: 329988
2018-04-13 05:03:28 +00:00
Bob Haarman fb2d342299 Revert "[LTO] Support filtering by hotness threshold"
This reverts commit 1f3bd185c53beb6aa68446974b7e80837abd6ef0 (r326107)
because it fails
ThinLTO/X86/diagnostic-handler-remarks-with-hotness.ll.

llvm-svn: 326975
2018-03-08 01:13:10 +00:00
Adam Nemet b4ce3573c4 [LTO] Support filtering by hotness threshold
This wires up -pass-remarks-hotness-threshold to LTO and ThinLTO.

Next is to change the clang driver to pass this
with -fdiagnostics-hotness-threshold.

Differential Revision: https://reviews.llvm.org/D41465

llvm-svn: 326107
2018-02-26 18:37:45 +00:00
Rafael Espindola 6a86e25d90 Pass a reference to a module to the bitcode writer.
This simplifies most callers as they are already using references or
std::unique_ptr.

llvm-svn: 325155
2018-02-14 19:11:32 +00:00
Teresa Johnson 791c98e4c8 [ThinLTO] Remove dead and dropped symbol declarations when possible
Summary:
Removing the dropped symbols will prevent indirect call promotion in the
ThinLTO Backend from adding a new reference to a symbol, which can
result in linker unsats. This can happen when we compile with a sample
profile collected from one binary by used for another, which may have
profiled targets that aren't used in the new binary.

Note that until dropDeadSymbols handles variables and aliases (in
progress), we may not be able to remove the declaration and can still
have an issue.

Reviewers: grimar, davidxl

Subscribers: mehdi_amini, inglorion, llvm-commits, eraman

Differential Revision: https://reviews.llvm.org/D42816

llvm-svn: 324299
2018-02-06 00:43:39 +00:00
Teresa Johnson 5a95c47730 [ThinLTO] Convert dead alias to declarations
Summary:
This complements the fixes in r323633 and r324075 which drop the
definitions of dead functions and variables, respectively.

Fixes PR36208.

Reviewers: grimar, rafael

Subscribers: mehdi_amini, llvm-commits, inglorion

Differential Revision: https://reviews.llvm.org/D42856

llvm-svn: 324242
2018-02-05 15:44:27 +00:00
George Rimar f5de271a92 [LTO] - Simplify. NFC.
llvm-svn: 324076
2018-02-02 12:21:26 +00:00
George Rimar 76c5fae2a0 [ThinLTO] - Fix for "ThinLTO inlines variables that should be discarded".
This fixes PR36187.

Patch teaches ThinLTO to drop non-prevailing variables, 
just like we recently did for functions (in r323633).

Differential revision: https://reviews.llvm.org/D42798

llvm-svn: 324075
2018-02-02 12:17:33 +00:00
George Rimar eaf5172ca6 [ThinLTO] - Stop internalizing and drop non-prevailing symbols.
Implementation marks non-prevailing symbols as not live in the summary.
Then them are dropped in backends.

Fixes https://bugs.llvm.org/show_bug.cgi?id=35938

Differential revision: https://reviews.llvm.org/D42107

llvm-svn: 323633
2018-01-29 08:03:30 +00:00
Eugene Leviant 28d8a49f42 [ThinLTO] Re-commit of dot dumper after test fix
llvm-svn: 323116
2018-01-22 13:35:40 +00:00
Eugene Leviant 72b9bdb71a Temporarily revert r323062 to investigate buildbot failures
llvm-svn: 323065
2018-01-21 10:22:19 +00:00
Eugene Leviant 453c976a63 [ThinLTO] Implement summary visualizer
Differential revision: https://reviews.llvm.org/D41297

llvm-svn: 323062
2018-01-21 07:27:32 +00:00
Reid Kleckner 3fc649cb76 [Support] Rename tool_output_file to ToolOutputFile, NFC
This class isn't similar to anything from the STL, so it shouldn't use
the STL naming conventions.

llvm-svn: 314050
2017-09-23 01:03:17 +00:00
Dehao Chen 3246dc3df1 Fix the bug that parseAAPipeline is not invoked in runNewPMPasses in release compiler.
Summary: The logic is guarded by "assert".

Reviewers: davidxl, davide, chandlerc

Reviewed By: davide, chandlerc

Subscribers: sanjoy, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D36195

llvm-svn: 309787
2017-08-02 03:03:19 +00:00
Dehao Chen 89d3226019 Update the new PM pipeline to make ICP aware if it is SamplePGO build.
Summary: In ThinLTO backend compile, OPTOptions are not set so that the ICP in ThinLTO backend does not know if it is a SamplePGO build, in which profile count needs to be annotated directly on call instructions. This patch cleaned up the PGOOptions handling logic and passes down PGOOptions to ThinLTO backend.

Reviewers: chandlerc, tejohnson, davidxl

Reviewed By: chandlerc

Subscribers: sanjoy, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D36052

llvm-svn: 309780
2017-08-02 01:28:31 +00:00
Tim Shen 4e912aa5af [ThinLTO] Move -lto-use-new-pm to llvm-lto2, and change it to -use-new-pm.
Summary:
As we teach Clang to use ThinkLTO + new PM, it's good for the users to
inject through Config, instead of setting a flag in the LTOBackend
library. Move the flag to llvm-lto2.

As it moves to llvm-lto2, a new name -use-new-pm seems simpler and as
clear.

Reviewers: davide, tejohnson

Subscribers: mehdi_amini, Prazek, inglorion, eraman, chandlerc, llvm-commits

Differential Revision: https://reviews.llvm.org/D33799

llvm-svn: 304492
2017-06-01 23:13:44 +00:00
Chandler Carruth 8b3be4e59d [PM/ThinLTO] Port the ThinLTO pipeline (both components) to the new PM.
Based on the original patch by Davide, but I've adjusted the API exposed
to just be different entry points rather than exposing more state
parameters. I've factored all the common logic out so that we don't have
any duplicate pipelines, we just stitch them together in different ways.
I think this makes the build easier to reason about and understand.

This adds a direct method for getting the module simplification pipeline
as well as a method to get the optimization pipeline. While not my
express goal, this seems nice and gives a good place comment about the
restrictions that are imposed on them.

I did make some minor changes to the way the pipelines are structured
here, but hopefully not ones that are significant or controversial:

1) I sunk the PGO indirect call promotion to only be run when we have
   PGO enabled (or as part of the special ThinLTO pipeline).

2) I made the extra GlobalOpt run in ThinLTO just happen all the time
   and at a slightly more powerful place (before we remove available
   externaly functions). This seems like general goodness and not a big
   compile time sink, so it didn't make sense to *only* use it in
   ThinLTO. Fewer differences in the pipeline makes everything simpler
   IMO.

3) I hoisted the ThinLTO stop point pre-link above the the RPO function
   attr inference. The RPO inference won't infer anything terribly
   meaningful pre-link (recursiveness?) so it didn't make a lot of
   sense. But if the placement of RPO inference starts to matter, we
   should move it to the canonicalization phase anyways which seems like
   a better place for it (and there is a FIXME to this effect!). But
   that seemed a bridge too far for this patch.

If we ever need to parameterize these pipelines more heavily, we can
always sink the logic to helper functions with parameters to keep those
parameters out of the public API. But the changes above seemed minor
that we could possible get away without the parameters entirely.

I added support for parsing 'thinlto' and 'thinlto-pre-link' names in
pass pipelines to make it easy to test these routines and play with them
in larger pipelines. I also added a really basic manifest of passes test
that will show exactly how the pipelines behave and work as well as
making updates to them clear.

Lastly, this factoring does introduce a nesting layer of module pass
managers in the default pipeline. I don't think this is a big deal and
the flexibility of decoupling the pipelines seems easily worth it.

Differential Revision: https://reviews.llvm.org/D33540

llvm-svn: 304407
2017-06-01 11:39:39 +00:00
Evgeniy Stepanov b9f1b014e1 Infer relocation model from module flags in relocatable LTO link.
Fix for PR33096.

llvm-svn: 303578
2017-05-22 21:11:35 +00:00
Peter Collingbourne fa58f7528e LTO: Mark undefined module asm symbols as used.
Marking them as used causes them to be considered visible outside of LTO. This
prevents the symbols from being internalized or discarded, either by GlobalDCE
or by summary-based dead stripping in ThinLTO.

This change makes it unnecessary to add these symbols to llvm.compiler.used
in the backend, as the symbols are kept alive by virtue of being external,
so remove the backend code that handles that.

Fixes PR32798.

Differential Revision: https://reviews.llvm.org/D32544

llvm-svn: 301438
2017-04-26 17:53:39 +00:00