Commit Graph

181 Commits

Author SHA1 Message Date
Volodymyr Sapsai 2ad768bb13 Revert "[ThinLTO] Add GraphTraits for FunctionSummaries"
It caused assertion failure
Assertion failed: (!DD.IsLambda && !MergeDD.IsLambda && "faked up lambda definition?"), function MergeDefinitionData, file /Users/buildslave/jenkins/workspace/clang-stage1-configure-RA/llvm/tools/clang/lib/Serialization/ASTReaderDecl.cpp, line 1675.

on the second stage build bots.

llvm-svn: 324932
2018-02-12 20:43:31 +00:00
Charles Saternos d3e7d19f59 [ThinLTO] Add GraphTraits for FunctionSummaries
Add GraphTraits definitions to the FunctionSummary and ModuleSummaryIndex classes. These GraphTraits will be used to construct find SCC's in ThinLTO analysis passes.

llvm-svn: 324854
2018-02-11 22:06:20 +00:00
Peter Collingbourne 7f1a5ba12a LTO: Include live bit in ThinLTO cache key.
As of r323633, this bit started controlling whether symbol definitions
appear in object files, and it also became sensitive to the prevailing
bit, so it needs to be included in the key.

Differential Revision: https://reviews.llvm.org/D43109

llvm-svn: 324711
2018-02-09 05:58:55 +00:00
Peter Collingbourne 3fe815d125 LTO: Also include dso-local bit for calls in ThinLTO cache key.
Differential Revision: https://reviews.llvm.org/D42934

llvm-svn: 324291
2018-02-05 23:46:32 +00:00
Peter Collingbourne b4edfb9af9 LTO: Include dso-local bit in ThinLTO cache key.
Differential Revision: https://reviews.llvm.org/D42713

llvm-svn: 324253
2018-02-05 17:17:51 +00:00
Vitaly Buka 59baf73a4d [ThinLTO/gold] Write empty imports even for modules with symbols
Summary: ThinLTO may skip object for other reasons, e.g. if there is no summary.

Reviewers: pcc, eugenis

Subscribers: mehdi_amini, inglorion, eraman, llvm-commits

Differential Revision: https://reviews.llvm.org/D42514

llvm-svn: 323818
2018-01-30 21:19:26 +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
George Rimar d328365b2e [LTO] - Introduce GlobalResolution::Prevailing flag.
It is NFC refactoring change that will make
D42107 a bit smaller.

Differential revision: https://reviews.llvm.org/D42528

llvm-svn: 323444
2018-01-25 17:23:27 +00:00
Rafael Espindola 349fe0aa87 Simplify. NFC.
Thanks to Teresa Johnson for the suggestion.

llvm-svn: 323365
2018-01-24 19:11:24 +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
Rafael Espindola 8a1ca67461 Don't drop dso_local in LTO.
LTO sets dso_local as an optimization, so don't clear it.

This avoid clearing it from undefined hidden symbols, which would then
fail the verifier.

llvm-svn: 322814
2018-01-18 05:38:43 +00:00
Vitaly Buka a5376f393e [LTO] Make processing of combined module more consistent
Summary:
1. Use stream 0 only for combined module. Previously if combined module was not
processes ThinLTO used the stream for own output. However small changes in input,
could trigger combined module  and shuffle outputs making life of llvm::LTO harder.

2. Always process combined module and write output to stream 0. Processing empty
combined module is cheap and allows llvm::LTO users to avoid implementing processing
which is already done in llvm::LTO.

Subscribers: mehdi_amini, inglorion, eraman, hiraditya

Differential Revision: https://reviews.llvm.org/D41267

llvm-svn: 320905
2017-12-16 02:10:00 +00:00
Eugene Leviant cb12249238 [ThinLTO] Disallow multiple prevailing defs
https://reviews.llvm.org/D41291

llvm-svn: 320825
2017-12-15 16:27:33 +00:00
Eugene Leviant 746f152dd6 [LLVMgold] Don't set undefined symbol as prevailing
Differential revision: https://reviews.llvm.org/D41113

llvm-svn: 320794
2017-12-15 09:18:21 +00:00
Sean Fertile 4595a915f6 [LTO][ThinLTO] Use the linker resolutions to mark global values as dso_local.
Now that we have a way to mark GlobalValues as local we can use the symbol
resolutions that the linker plugin provides as part of lto/thinlto link
step to refine the compilers view on what symbols will end up being local.

Originally commited as r317374, but reverted in r317395 to update some missed
tests.

Differential Revision: https://reviews.llvm.org/D35702

llvm-svn: 317408
2017-11-04 17:04:39 +00:00
Sean Fertile 39770ca0a1 Revert "[LTO][ThinLTO] Use the linker resolutions to mark global values ..."
Changes more tests then expected on one of the build bots.
reverting to investigate.

This reverts https://llvm.org/svn/llvm-project/llvm/trunk@317374

llvm-svn: 317395
2017-11-04 01:54:20 +00:00
Sean Fertile 36528c2a9b [LTO][ThinLTO] Use the linker resolutions to mark global values as dso_local.
Now that we have a way to mark GlobalValues as local we can use the symbol
resolutions that the linker plugin provides as part of lto/thinlto link
step to refine the compilers view on what symbols will end up being local.

Differential Revision: https://reviews.llvm.org/D35702

llvm-svn: 317374
2017-11-03 21:45:55 +00:00
Peter Collingbourne 9fb6e1a037 LTO: Apply global DCE to ThinLTO modules at LTO opt level 0.
This is necessary because DCE is applied to full LTO modules. Without
this change, a reference from a dead ThinLTO global to a dead full
LTO global will result in an undefined reference at link time.

This problem is only observable when --gc-sections is disabled, or
when targeting COFF, as the COFF port of lld requires all symbols to
have a definition even if all references are dead (this is consistent
with link.exe).

This change also adds an EliminateAvailableExternally pass at -O0. This
is necessary to handle the situation on Windows where a non-prevailing
copy of a linkonce_odr function has an SEH filter function; any
such filters must be DCE'd because they will contain a call to the
llvm.localrecover intrinsic, passing as an argument the address of the
function that the filter belongs to, and llvm.localrecover requires
this function to be defined locally.

Fixes PR35142.

Differential Revision: https://reviews.llvm.org/D39484

llvm-svn: 317108
2017-11-01 17:58:39 +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
Peter Collingbourne b9b6025328 LowerTypeTests: Add import/export support for targets without absolute symbol constants.
The rationale is the same as for r312967.

Differential Revision: https://reviews.llvm.org/D37408

llvm-svn: 312968
2017-09-11 22:49:10 +00:00
Peter Collingbourne b15a35e604 WholeProgramDevirt: Add import/export support for targets without absolute symbol constants.
Not all targets support the use of absolute symbols to export
constants. In particular, ARM has a wide variety of constant encodings
that cannot currently be relocated by linkers. So instead of exporting
the constants using symbols, export them directly in the summary.
The values of the constants are left as zeroes on targets that support
symbolic exports.

This may result in more cache misses when targeting those architectures
as a result of arbitrary changes in constant values, but this seems
somewhat unavoidable for now.

Differential Revision: https://reviews.llvm.org/D37407

llvm-svn: 312967
2017-09-11 22:34:42 +00:00
Evgeniy Stepanov 3427d17cf8 Fix thinlto cache key computation for cfi-icall.
Summary:
Fixed PR33966.

CFI code generation for users (not just callers) of a function depends
on whether this function has a jumptable entry or not. This
information needs to be encoded in of thinlto cache key.

We filter the jumptable list against functions that are actually
referenced in the current module.

Subscribers: mehdi_amini, inglorion, eraman, hiraditya

Differential Revision: https://reviews.llvm.org/D36346

llvm-svn: 310536
2017-08-09 23:24:07 +00:00
Rafael Espindola 79e238afee Delete Default and JITDefault code models
IMHO it is an antipattern to have a enum value that is Default.

At any given piece of code it is not clear if we have to handle
Default or if has already been mapped to a concrete value. In this
case in particular, only the target can do the mapping and it is nice
to make sure it is always done.

This deletes the two default enum values of CodeModel and uses an
explicit Optional<CodeModel> when it is possible that it is
unspecified.

llvm-svn: 309911
2017-08-03 02:16:21 +00:00
Peter Collingbourne e776dd9ca2 LTO: Export functions referenced by the CFI jump table.
If the LowerTypeTests pass decides to add a function to a jump
table for CFI, it will add its name to the set cfiFunctionDefs,
which among other things will cause the function to be renamed in
the ThinLTO backend.

One other thing that we must do with such functions is to not
internalize them, because the jump table in the full LTO object will
contain a reference to the actual function body in the ThinLTO object.

This patch handles that by ensuring that we export any functions
whose names appear in the cfiFunctionDefs set.

Fixes PR33831.

Differential Revision: https://reviews.llvm.org/D35605

llvm-svn: 308504
2017-07-19 18:18:19 +00:00
Dehao Chen 5d96ee4fab Use DenseMap instead std::map for GVSummaryMapTy.
Summary: This speeds-up thin-link by ~47% for large programs.

Reviewers: tejohnson

Reviewed By: tejohnson

Subscribers: sanjoy, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D35148

llvm-svn: 307578
2017-07-10 20:12:54 +00:00
Davide Italiano 6a5fbe52fa [LTO] Fix the interaction between linker redefined symbols and ThinLTO
This is the same as r304719 but for ThinLTO.
The substantial difference is that in this case we don't have
whole visibility, just the summary.
In the LTO case, when we got the resolution for the input file we
could just see if the linker told us whether a symbol was linker
redefined (using --wrap or --defsym) and switch the linkage directly
for the GV.

Here, we have the summary. So, we record that the linkage changed
from <whatever it was> to $weakany to prevent IPOs across this symbol
boundaries and actually just switch the linkage at FunctionImport time.

This patch should also fixes the lld bits (as all the scaffolding for
communicating if a symbol is linker redefined should be there & should
be the same), but I'll make sure to add some tests there as well.

Fixes PR33192.

Differential Revision:  https://reviews.llvm.org/D35064

llvm-svn: 307303
2017-07-06 19:58:26 +00:00
Brian Gesiak 44e5f6c4ac [ORE] Unify spelling as "diagnostics hotness"
Summary:
To enable profile hotness information in diagnostics output, Clang takes
the option `-fdiagnostics-show-hotness` -- that's "diagnostics", with an
"s" at the end. Clang also defines `CodeGenOptions::DiagnosticsWithHotness`.

LLVM, on the other hand, defines
`LLVMContext::getDiagnosticHotnessRequested` -- that's "diagnostic", not
"diagnostics". It's a small difference, but it's confusing, typo-inducing, and
frustrating.

Add a new method with the spelling "diagnostics", and "deprecate" the
old spelling.

Reviewers: anemet, davidxl

Reviewed By: anemet

Subscribers: llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D34864

llvm-svn: 306848
2017-06-30 18:13:59 +00:00
Teresa Johnson b247ffbaed [LTO] Remove values from non-prevailing comdats
Summary:
When linking a regular LTO module, if it has any non-prevailing values
(dropped to available_externally) in comdats, we need to do more than
just remove those values from their comdat. We also remove all values
from that comdat, so as to avoid leaving an incomplete comdat.

This is necessary in case we are compiling in mixed regular and ThinLTO
mode, since the resulting regularLTO native object is always linked into
the final binary first. We need to prevent the linker from selecting an
incomplete comdat that was not the prevailing copy.

Fixes PR32980.

Reviewers: pcc, rafael

Subscribers: mehdi_amini, david2050, llvm-commits, inglorion

Differential Revision: https://reviews.llvm.org/D34803

llvm-svn: 306826
2017-06-30 14:03:24 +00:00
Peter Collingbourne 7e85b26549 Silence warning with assertions disabled.
llvm-svn: 305485
2017-06-15 17:41:32 +00:00
Peter Collingbourne dbd2fed6a1 Apply summary-based dead stripping to regular LTO modules with summaries.
If a regular LTO module has a summary index, then instead of linking
it into the combined regular LTO module right away, add it to the
combined summary index and associate it with a special module that
represents the combined regular LTO module.

Any such modules are linked during LTO::run(), at which time we use
the results of summary-based dead stripping to control whether to
link prevailing symbols.

Differential Revision: https://reviews.llvm.org/D33922

llvm-svn: 305482
2017-06-15 17:26:13 +00:00
Peter Collingbourne c00c2b246b Object: Factor out the code for creating the irsymtab for an arbitrary bitcode file.
This code now lives in lib/Object. The idea is that it can now be reused by
IRObjectFile among other things.

Differential Revision: https://reviews.llvm.org/D31921

llvm-svn: 304958
2017-06-08 01:26:14 +00:00
Dmitry Mikulin db3b87b2c0 Symbols re-defined with -wrap and -defsym need to be excluded from inter-
procedural optimizations to prevent dropping symbols and allow the linker
to process re-directs.

PR33145: --wrap doesn't work with lto.
Differential Revision: https://reviews.llvm.org/D33621

llvm-svn: 304719
2017-06-05 16:24:25 +00:00
Evgeniy Stepanov 659b3bc77d Move summary dead stripping before regular LTO.
This way dead stripping results are recorded in combined summary and
can be used in regular LTO passes.

Differential Revision: https://reviews.llvm.org/D33615

llvm-svn: 304577
2017-06-02 18:24:17 +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
Evgeniy Stepanov 56584bbf16 (NFC) Track global summary liveness in GVFlags.
Replace GVFlags::LiveRoot with GVFlags::Live and use that instead of
all the DeadSymbols sets. This is refactoring in order to make
liveness information available in the RegularLTO pipeline.

llvm-svn: 304466
2017-06-01 20:30:06 +00:00
Davide Italiano d4db116af8 [lib/LTO] Don't reinvent the code for switching linkage.
Differential Revision:  https://reviews.llvm.org/D33582

llvm-svn: 304040
2017-05-26 21:56:14 +00:00
Peter Collingbourne f87197ad91 LTO: Do summary-based prevailing symbol resolution at --lto-O0.
Prevailing symbol resolution is necessary for correctness. Without
this we can end up dropping a referenced linkonce symbol from the link.

Differential Revision: https://reviews.llvm.org/D33570

llvm-svn: 303939
2017-05-25 23:40:11 +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 6f0ecca3b5 IR: Give function GlobalValue::getRealLinkageName() a less misleading name: dropLLVMManglingEscape().
This function gives the wrong answer on some non-ELF platforms in some
cases. The function that does the right thing lives in Mangler.h. To try to
discourage people from using this function, give it a different name.

Differential Revision: https://reviews.llvm.org/D33162

llvm-svn: 303134
2017-05-16 00:39:01 +00:00
Peter Collingbourne 9667b91b13 Re-apply r302108, "IR: Use pointers instead of GUIDs to represent edges in the module summary. NFCI."
with a fix for the clang backend.

llvm-svn: 302176
2017-05-04 18:03:25 +00:00
Eric Liu f6039f255e Revert "IR: Use pointers instead of GUIDs to represent edges in the module summary. NFCI."
This reverts commit r302108. This causes crash in clang bootstrap with LTO.

Contacted the auther in the original commit.

llvm-svn: 302140
2017-05-04 11:49:39 +00:00
Peter Collingbourne 5f85a9deda IR: Use pointers instead of GUIDs to represent edges in the module summary. NFCI.
When profiling a no-op incremental link of Chromium I found that the functions
computeImportForFunction and computeDeadSymbols were consuming roughly 10% of
the profile. The goal of this change is to improve the performance of those
functions by changing the map lookups that they were previously doing into
pointer dereferences.

This is achieved by changing the ValueInfo data structure to be a pointer to
an element of the global value map owned by ModuleSummaryIndex, and changing
reference lists in the GlobalValueSummary to hold ValueInfos instead of GUIDs.
This means that a ValueInfo will take a client directly to the summary list
for a given GUID.

Differential Revision: https://reviews.llvm.org/D32471

llvm-svn: 302108
2017-05-04 03:36:16 +00:00
Peter Collingbourne 74d22dd7dc Bitcode: Make the summary reader responsible for merging. NFCI.
This is to prepare for an upcoming change which uses pointers instead of
GUIDs to represent references.

Differential Revision: https://reviews.llvm.org/D32469

llvm-svn: 301843
2017-05-01 22:04:36 +00:00
Peter Collingbourne c15d60b772 Object: Remove ModuleSummaryIndexObjectFile class.
Differential Revision: https://reviews.llvm.org/D32195

llvm-svn: 301832
2017-05-01 20:42:32 +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
Peter Collingbourne 8446f1fe6a Object, LTO: Add target triple to irsymtab and LTO API.
Start using it in LLD to avoid needing to read bitcode again just to get the
target triple, and in llvm-lto2 to avoid printing symbol table information
that is inappropriate for the target.

Differential Revision: https://reviews.llvm.org/D32038

llvm-svn: 300300
2017-04-14 02:55:06 +00:00
Peter Collingbourne 942fa56f40 Support: Add a VCSRevision.h header file.
This is a magic header file supported by the build system that provides a
single definition, LLVM_REVISION, containing an LLVM revision identifier,
if available. This functionality previously lived in the LTO library, but
I am moving it out to lib/Support because I want to also start using it in
lib/Object to create the IR symbol table.

This change also fixes a bug where LLVM_REVISION was never actually being
used in lib/LTO because the macro HAS_LLVM_REVISION was never defined (it
was misspelled as HAVE_SVN_VERSION_INC in lib/LTO/CMakeLists.txt, and was
only being defined in a non-existent file Version.cpp).

I also changed the code to use "git rev-parse --git-dir" to locate the .git
directory, instead of looking for it in the LLVM source root directory,
which makes this compatible with monorepos as well as git worktrees.

Differential Revision: https://reviews.llvm.org/D31985

llvm-svn: 300160
2017-04-13 01:26:12 +00:00
Bob Haarman d6aea71957 LTO: call getRealLinkageName on IRNames before feeding to getGUID
Summary: GlobalValue has two getGUID methods: an instance method and a static method. The static method takes a string, which is expected to be what GlobalValue::getRealLinkageName() would return. In LTO.cpp, we were not doing this consistently, sometimes passing an IR name instead. This change makes it so that we call getRealLinkageName() first, making the static getGUID return value consistent with the instance method. Without this change, compiling FileCheck with ThinLTO on Windows fails with numerous undefined symbol errors. With the change, it builds successfully.

Reviewers: pcc, rnk

Reviewed By: pcc

Subscribers: tejohnson, mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D31444

llvm-svn: 299268
2017-03-31 21:56:30 +00:00
Peter Collingbourne 7b30f16c9f Re-apply r299168 and r299169 now that the libdeps are fixed.
llvm-svn: 299184
2017-03-31 04:47:07 +00:00
Peter Collingbourne c66018e247 Move llvm::emitLinkerFlagsForGlobalCOFF() to Mangler.
llvm-svn: 299183
2017-03-31 04:46:50 +00:00
Peter Collingbourne f10698b940 Revert r299168 and r299169 due to library dependency issues.
http://bb.pgr.jp/builders/i686-mingw32-RA-on-linux/builds/25073/steps/build_llvmclang/logs/stdio

llvm-svn: 299171
2017-03-31 02:44:50 +00:00
Peter Collingbourne d9717aa0e4 LTO: Reduce memory consumption by creating an in-memory symbol table for InputFiles. NFCI.
Introduce symbol table data structures that can be potentially written to
disk, have the LTO library build those data structures using temporarily
constructed modules and redirect the LTO library implementation to go through
those data structures. This allows us to remove the LLVMContext and Modules
owned by InputFile.

With this change I measured a peak memory consumption decrease from 5.4GB to
2.8GB in a no-op incremental ThinLTO link of Chromium on Linux. The impact on
memory consumption is larger in COFF linkers where we are currently forced
to materialize all metadata in order to read linker options. Peak memory
consumption linking a large piece of Chromium for Windows with full LTO and
debug info decreases from >64GB (OOM) to 15GB.

Part of PR27551.

Differential Revision: https://reviews.llvm.org/D31364

llvm-svn: 299168
2017-03-31 02:28:30 +00:00
Peter Collingbourne 192d8520de More accurate header inclusions. NFC.
llvm-svn: 298960
2017-03-28 23:35:34 +00:00
Peter Collingbourne 0d56b959ad LTO: Replace InputFile::Symbol::getFlags() with predicate accessors. NFC.
This makes the predicates independent of the flag representation
and makes the code a little easier to read.

llvm-svn: 298951
2017-03-28 22:31:35 +00:00
Peter Collingbourne 711284b017 LTO: Hash type identifier resolutions for WholeProgramDevirt.
Differential Revision: https://reviews.llvm.org/D30555

llvm-svn: 297514
2017-03-10 21:37:10 +00:00
Peter Collingbourne 780a4dd35f LTO: Hash type identifier resolutions for LowerTypeTests.
Differential Revision: https://reviews.llvm.org/D30553

llvm-svn: 297513
2017-03-10 21:35:17 +00:00
Peter Collingbourne 54a52b7569 LTO: Hash the set of imported symbols for each module.
This set may affect code generation and is sensitive to link order (and
possibly in the future to the linker's choice of prevailing symbol), so we
need to include it.

Differential Revision: https://reviews.llvm.org/D30586

llvm-svn: 296907
2017-03-03 20:25:30 +00:00
Tobias Edler von Koch f454b9eadf [LTO] Add ability to emit assembly to new LTO API
Summary:
Add a field to LTO::Config, CGFileType, to select the file type to emit (object
or assembly). This is useful for testing and to implement -save-temps.

Reviewers: tejohnson, mehdi_amini, pcc

Reviewed By: mehdi_amini

Subscribers: davide, llvm-commits

Differential Revision: https://reviews.llvm.org/D29475

llvm-svn: 295226
2017-02-15 20:36:36 +00:00
Davide Italiano 690ed9dec7 [LTO] Share the optimization remarks setup between Thin/Full LTO.
llvm-svn: 294807
2017-02-10 23:49:38 +00:00
Peter Collingbourne e6fd9ff96a IRMover: Merge flags LinkModuleInlineAsm and IsPerformingImport.
Currently these flags are always the inverse of each other, so there is
no need to keep them separate.

Differential Revision: https://reviews.llvm.org/D29471

llvm-svn: 294016
2017-02-03 17:01:14 +00:00
Mehdi Amini 1380edf4ef Revert "[ThinLTO] Add an auto-hide feature"
This reverts commit r293970.

After more discussion, this belongs to the linker side and
there is no added value to do it at this level.

llvm-svn: 293993
2017-02-03 07:41:43 +00:00
Mehdi Amini b0a8ff71e5 [ThinLTO] Add an auto-hide feature
When a symbol is not exported outside of the
DSO, it is can be hidden. Usually we try to internalize
as much as possible, but it is not always possible, for
instance a symbol can be referenced outside of the LTO
unit, or there can be cross-module reference in ThinLTO.

This is a recommit of r293912 after fixing build failures,
and a recommit of r293918 after fixing LLD tests.

Differential Revision: https://reviews.llvm.org/D28978

llvm-svn: 293970
2017-02-03 00:32:38 +00:00
Mehdi Amini 21c89dc920 Revert "[ThinLTO] Add an auto-hide feature"
This reverts commit r293918, one lld test does not pass.

llvm-svn: 293961
2017-02-02 23:20:36 +00:00
Bob Haarman dd4ebc1d3b [lto] add getLinkerOpts()
Summary: Some compilers, including MSVC and Clang, allow linker options to be specified in source files. In the legacy LTO API, there is a getLinkerOpts() method that returns linker options for the bitcode module being processed. This change adds that method to the new API, so that the COFF linker can get the right linker options when using the new LTO API.

Reviewers: pcc, ruiu, mehdi_amini, tejohnson

Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D29207

llvm-svn: 293950
2017-02-02 23:00:49 +00:00
Mehdi Amini 97624fb1ec [ThinLTO] Add an auto-hide feature
When a symbol is not exported outside of the
DSO, it is can be hidden. Usually we try to internalize
as much as possible, but it is not always possible, for
instance a symbol can be referenced outside of the LTO
unit, or there can be cross-module reference in ThinLTO.

This is a recommit of r293912 after fixing build failures.

Differential Revision: https://reviews.llvm.org/D28978

llvm-svn: 293918
2017-02-02 18:31:35 +00:00
Mehdi Amini 827600deaf Revert "[ThinLTO] Add an auto-hide feature"
This reverts r293912, bots are broken.

llvm-svn: 293914
2017-02-02 18:24:37 +00:00
Mehdi Amini dc5a7444f0 [ThinLTO] Add an auto-hide feature
When a symbol is not exported outside of the
DSO, it is can be hidden. Usually we try to internalize
as much as possible, but it is not always possible, for
instance a symbol can be referenced outside of the LTO
unit, or there can be cross-module reference in ThinLTO.

Differential Revision: https://reviews.llvm.org/D28978

llvm-svn: 293912
2017-02-02 18:13:46 +00:00
Peter Collingbourne 4613626d49 LTO: Link non-prevailing weak_odr or linkonce_odr globals into the combined module with available_externally linkage.
These linkages mean that the ultimately prevailing symbol will have the same
semantics as any non-prevailing copy of the symbol, so we are free to ignore
the linker's resolution.

Differential Revision: https://reviews.llvm.org/D29367

llvm-svn: 293865
2017-02-02 05:22:42 +00:00
Peter Collingbourne c387e70c69 Linker: Move special casing for available_externally in IRMover to clients. NFCI.
The goal is to simplify the semantic model for clients of IRMover.

Differential Revision: https://reviews.llvm.org/D29435

llvm-svn: 293864
2017-02-02 05:12:15 +00:00
Mehdi Amini f39ce99474 [ThinLTO] Don't perform computeDeadSymbols during O0 link, as the result is never used (NFC)
llvm-svn: 292679
2017-01-20 23:34:12 +00:00
Peter Collingbourne e02b74e294 IPO, LTO: Plumb the summary from the LTO API into the pass manager.
Differential Revision: https://reviews.llvm.org/D28840

llvm-svn: 292661
2017-01-20 22:18:52 +00:00
Teresa Johnson 4566c6db87 [ThinLTO] Drop non-prevailing non-ODR weak to declarations
Summary:
Allow non-ODR weak/linkonce non-prevailing copies to be marked
as available_externally in the index. Add support for dropping these to
declarations in the backend.

Reviewers: mehdi_amini, pcc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28806

llvm-svn: 292656
2017-01-20 21:54:58 +00:00
Peter Collingbourne 58ffcfbffa LTO: Flush the resolution file after writing to it.
Without this the file could be truncated if the linker crashes.

llvm-svn: 292532
2017-01-19 23:10:14 +00:00
Teresa Johnson 6c475a7595 ThinLTO: add early "dead-stripping" on the Index
Summary:
Using the linker-supplied list of "preserved" symbols, we can compute
the list of "dead" symbols, i.e. the one that are not reachable from
a "preserved" symbol transitively on the reference graph.
Right now we are using this information to mark these functions as
non-eligible for import.

The impact is two folds:
- Reduction of compile time: we don't import these functions anywhere
  or import the function these symbols are calling.
- The limited number of import/export leads to better internalization.

Patch originally by Mehdi Amini.

Reviewers: mehdi_amini, pcc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D23488

llvm-svn: 291177
2017-01-05 21:34:18 +00:00
Davide Italiano 6309895770 [lib/LTO] Simplify logic removing set but unused variable. NFCI.
Reported by David Binderman and ack'ed by Teresa on IRC.
PR: 31527

llvm-svn: 291000
2017-01-04 20:37:57 +00:00
Teresa Johnson a61f5e3796 [ThinLTO] Import composite types as declarations
Summary:
When reading the metadata bitcode, create a type declaration when
possible for composite types when we are importing. Doing this in
the bitcode reader saves memory. Also it works naturally in the case
when the type ODR map contains a definition for the same composite type
because it was used in the importing module (buildODRType will
automatically use the existing definition and not create a type
declaration).

For Chromium built with -g2, this reduces the aggregate size of the
generated native object files by 66% (from 31G to 10G). It reduced
the time through the ThinLTO link and backend phases by about 20% on
my machine.

Reviewers: mehdi_amini, dblaikie, aprantl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D27775

llvm-svn: 289993
2016-12-16 21:25:01 +00:00
Dehao Chen 2797800595 Pass sample pgo flags to thinlto.
Summary: ThinLTO needs to invoke SampleProfileLoader pass during link time in order to annotate profile correctly after module importing.

Reviewers: davidxl, mehdi_amini, tejohnson

Subscribers: pcc, davide, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D27790

llvm-svn: 289957
2016-12-16 16:48:46 +00:00
Davide Italiano 2ceb628f36 [LTO] Reject modules without datalayout.
Also, udpate the ~60 failing tests in the tree which did
not contain a valid datalayout.
This fixes PR31123. lld will be updated in a following patch,
immediately after this is committed.

Differential Revision:  https://reviews.llvm.org/D27082

llvm-svn: 289719
2016-12-14 21:57:04 +00:00
Peter Collingbourne 1a0720e8c4 LTO: Add support for multi-module bitcode files.
Differential Revision: https://reviews.llvm.org/D27313

llvm-svn: 289621
2016-12-14 01:17:59 +00:00
Peter Collingbourne ad90369a94 LTO: Port the new LTO API to ModuleSymbolTable.
Differential Revision: https://reviews.llvm.org/D27077

llvm-svn: 289574
2016-12-13 19:43:49 +00:00
Teresa Johnson 040cc16835 [ThinLTO] Import only necessary DICompileUnit fields
Summary:
As discussed on mailing list, for ThinLTO importing we don't need
to import all the fields of the DICompileUnit. Don't import enums,
macros, retained types lists. Also only import local scoped imported
entities. Since we don't currently import any global variables,
we also don't need to import the list of global variables (added an
assert to verify none are being imported).

This is being done by pre-populating the value map entries to map
the unneeded metadata to nullptr. For the imported entities, we can
simply replace the source module's list with a new list containing
only those needed imported entities. This is done in the IRLinker
constructor so that value mapping automatically does the desired
mapping.

Reviewers: mehdi_amini, dexonsmith, dblaikie, aprantl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D27635

llvm-svn: 289441
2016-12-12 16:09:30 +00:00
Peter Collingbourne f4257528e9 LTO: Hash the parts of the LTO configuration that affect code generation.
Most importantly, we need to hash the relocation model, otherwise we can
end up trying to link non-PIC object files into PIEs or DSOs.

Differential Revision: https://reviews.llvm.org/D27556

llvm-svn: 289024
2016-12-08 05:28:30 +00:00
Peter Collingbourne dac43b49bd LTO: Remove ModuleLoader, make loadModuleFromBuffer static and move into its only client, ThinLTOCodeGenerator.
This is no longer the recommended way to load modules for importing, so it should not be public API.

Differential Revision: https://reviews.llvm.org/D27292

llvm-svn: 288316
2016-12-01 05:52:32 +00:00
Peter Collingbourne fb8c2a4a6b LTO: Remove Symbol::getIRName().
Its only use was in the LTO implementation. Also document
Symbol::getName().

llvm-svn: 288302
2016-12-01 02:51:12 +00:00
Benjamin Kramer ffd3715d16 Give some helper classes/functions internal linkage. NFC.
llvm-svn: 287462
2016-11-19 20:44:26 +00:00
Peter Collingbourne d9445c49ad Bitcode: Change module reader functions to return an llvm::Expected.
Differential Revision: https://reviews.llvm.org/D26562

llvm-svn: 286752
2016-11-13 07:00:17 +00:00
Peter Collingbourne 6de481a378 Bitcode: Change getModuleSummaryIndex() to return an llvm::Expected.
Differential Revision: https://reviews.llvm.org/D26539

llvm-svn: 286624
2016-11-11 19:50:39 +00:00
Peter Collingbourne cd513a41c1 Bitcode: Clean up error handling for certain bitcode query functions.
The functions getBitcodeTargetTriple(), isBitcodeContainingObjCCategory(),
getBitcodeProducerString() and hasGlobalValueSummary() now return errors
via their return value rather than via the diagnostic handler.

To make this work, re-implement these functions using non-member functions
so that they can be used without the LLVMContext required by BitcodeReader.

Differential Revision: https://reviews.llvm.org/D26532

llvm-svn: 286623
2016-11-11 19:50:24 +00:00
Teresa Johnson ad17679abd Split Bitcode/ReaderWriter.h into separate reader and writer headers
Summary:
Split ReaderWriter.h which contains the APIs into both the BitReader and
BitWriter libraries into BitcodeReader.h and BitcodeWriter.h.

This is to address Chandler's concern about sharing the same API header
between multiple libraries (BitReader and BitWriter). That concern is
why we create a single bitcode library in our downstream build of clang,
which led to r286297 being reverted as it added a dependency that
created a cycle only when there is a single bitcode library (not two as
in upstream).

Reviewers: mehdi_amini

Subscribers: dlj, mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D26502

llvm-svn: 286566
2016-11-11 05:34:58 +00:00
Mehdi Amini 41af43092c Make the Error class constructor protected
This is forcing to use Error::success(), which is in a wide majority
of cases a lot more readable.

Differential Revision: https://reviews.llvm.org/D26481

llvm-svn: 286561
2016-11-11 04:28:40 +00:00
Peter Collingbourne 7f00d0a125 Bitcode: Change the materializer interface to return llvm::Error.
Differential Revision: https://reviews.llvm.org/D26439

llvm-svn: 286382
2016-11-09 17:49:19 +00:00
Peter Collingbourne e2dcf7c3a1 IR, Bitcode: Change bitcode reader to no longer own its memory buffer.
Unique ownership is just one possible ownership pattern for the memory buffer
underlying the bitcode reader. In practice, as this patch shows, ownership can
often reside at a higher level. With the upcoming change to allow multiple
modules in a single bitcode file, it will no longer be appropriate for
modules to generally have unique ownership of their memory buffer.

The C API exposes the ownership relation via the LLVMGetBitcodeModuleInContext
and LLVMGetBitcodeModuleInContext2 functions, so we still need some way for
the module to own the memory buffer. This patch does so by adding an owned
memory buffer field to Module, and using it in a few other places where it
is convenient.

Differential Revision: https://reviews.llvm.org/D26384

llvm-svn: 286214
2016-11-08 06:03:43 +00:00
Teresa Johnson 002af9bbce [ThinLTO] Disable importing and other cross-module optis at -O0
Summary:
There is no point to importing at -O0, since we won't inline. We should
also disable other cross-module optimizations.

(Plan to backport this fix to the 3.9 branch to fix PR30774)

Reviewers: pcc

Subscribers: johanengelen, mehdi_amini

Differential Revision: https://reviews.llvm.org/D25918

llvm-svn: 285648
2016-10-31 22:12:21 +00:00
Teresa Johnson 3bc8abdffc [ThinLTO] Correctly resolve linkonce when importing aliasee
Summary:
When we have an aliasee that is linkonce, while we can't convert
the non-prevailing copies to available_externally, we still need to
convert the prevailing copy to weak. If a reference to the aliasee
is exported, not converting a copy to weak will result in undefined
references when the linkonce is removed in its original module.

Add a new test and update existing tests.

Reviewers: mehdi_amini

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D26076

llvm-svn: 285512
2016-10-30 05:15:23 +00:00
Rafael Espindola 20aa1779d0 fix warning
llvm-svn: 285064
2016-10-25 12:28:26 +00:00
Rafael Espindola 7912110ddc Make the LTO comdat api more symbol table friendly.
In an IR symbol table I would expect the comdats to be represented as:

- A table of strings, one for each comdat name.
- Each symbol has an optional index into that table.

The natural api for accessing that would be

InputFile:
ArrayRef<StringRef> getComdatTable() const;

Symbol:
int getComdatIndex() const;

This patch implements an API as close to that as possible.  The
implementation on top of the current IRObjectFile is a bit hackish,
but should map just fine over a symbol table and is very convenient to
use.

llvm-svn: 285061
2016-10-25 12:02:03 +00:00
Teresa Johnson ec544c552e [ThinLTO] Default backend threads to heavyweight_hardware_concurrency
Summary:
Changes default backend parallelism from thread::hardware_concurrency to
the new llvm::heavyweight_hardware_concurrency, which for X86 Linux
defaults to the number of physical cores (and will fall back to
thread::hardware_concurrency otherwise). This avoid oversubscribing
the physical cores using hyperthreading.

Reviewers: mehdi_amini, pcc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D25775

llvm-svn: 284618
2016-10-19 17:35:01 +00:00
Teresa Johnson 4b9b379172 [ThinLTO] Don't link module level assembly when importing
Module inline asm was always being linked/concatenated
when running the IRLinker. This is correct for full LTO but not when
we are importing for ThinLTO, as it can result in multiply defined
symbols when the module asm defines a global symbol.

In order to test with llvm-lto2, I had to work around PR30396,
where a symbol that is defined in module assembly but defined in the
LLVM IR appears twice. Added workaround to llvm-lto2 with a FIXME.

Fixes PR30610.

Reviewers: mehdi_amini

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D25359

llvm-svn: 284030
2016-10-12 18:39:29 +00:00