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* [ThinLTOBitcodeWriter] Emit summaries for regular LTO modulesVlad Tsyrklevich2018-06-011-4/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Emit summaries for bitcode modules that are only destined for the regular LTO portion of the build so they can participate in summary-based dead stripping. This change reduces the size of a nacl_helper build with cfi-icall enabled by 7%, removing the majority of the overhead due to enabling cfi-icall. The cfi-icall size increase was caused by compiling in lots of unused code and cfi-icall generating jumptable references to unused symbols that could no longer be removed by -Wl,-gc-sections. Increasing the visibility of summary-based dead stripping prevented jumptable entries being created for unused symbols from the regular LTO portion of the build. Reviewers: pcc Reviewed By: pcc Subscribers: dschuff, mehdi_amini, inglorion, eraman, llvm-commits, kcc Differential Revision: https://reviews.llvm.org/D47594 llvm-svn: 333768
* Extend the GlobalObject metadata interfaceBenjamin Kramer2018-05-311-21/+14
| | | | | | | | | | | | - Make eraseMetadata return whether it changed something - Wire getMetadata for a single MDNode efficiently into the attachment map - Add hasMetadata, which is less weird than checking getMetadata == nullptr on a multimap. Use it to simplify code. llvm-svn: 333649
* LowerTypeTests: Propagate symver directivesVlad Tsyrklevich2018-04-201-2/+21
| | | | | | | | | | | | | | | | | | | | | | Summary: This change fixes https://crbug.com/834474, a build failure caused by LowerTypeTests not preserving .symver symbol versioning directives for exported functions. Emit symver information to ThinLTO summary data and then propagate symver directives for exported functions to the merged module. Emitting symver information to the summaries increases the size of intermediate build artifacts for a Chromium build by less than 0.2%. Reviewers: pcc Reviewed By: pcc Subscribers: tejohnson, mehdi_amini, eraman, llvm-commits, eugenis, kcc Differential Revision: https://reviews.llvm.org/D45798 llvm-svn: 330387
* Pass a module reference to CloneModule.Rafael Espindola2018-02-141-1/+1
| | | | | | | It can never be null and most callers were already using references or std::unique_ptr. llvm-svn: 325160
* Pass a reference to a module to the bitcode writer.Rafael Espindola2018-02-141-9/+8
| | | | | | | This simplifies most callers as they are already using references or std::unique_ptr. llvm-svn: 325155
* Recommit r324455 "[ThinLTO] - Simplify code in ThinLTOBitcodeWriter."George Rimar2018-02-081-40/+12
| | | | | | | | | | | | | With fix: reimplemented. Original commit message: Recently introduced convertToDeclaration is very similar to code used in filterModule function. Patch reuses it to reduce duplication. Differential revision: https://reviews.llvm.org/D42971 llvm-svn: 324574
* Revert r324455 "[ThinLTO] - Simplify code in ThinLTOBitcodeWriter."George Rimar2018-02-071-11/+37
| | | | | | | It broke BB: http://lab.llvm.org:8011/builders/sanitizer-windows/builds/23721 llvm-svn: 324458
* [ThinLTO] - Simplify code in ThinLTOBitcodeWriter.George Rimar2018-02-071-37/+11
| | | | | | | | | | Recently introduced convertToDeclaration is very similar to code used in filterModule function. Patch reuses it to reduce duplication. Differential revision: https://reviews.llvm.org/D42971 llvm-svn: 324455
* ThinLTOBitcodeWriter: Do not include module-level inline asm in the merged ↵Peter Collingbourne2018-02-061-0/+1
| | | | | | | | | | | module. If the inline asm provides the definition of a symbol, this can result in duplicate symbol errors. Differential Revision: https://reviews.llvm.org/D42944 llvm-svn: 324313
* LowerTypeTests: Add limited support for aliasesVlad Tsyrklevich2018-01-101-0/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: LowerTypeTests moves some function definitions from individual object files to the merged module, leaving a stub to be called in the merged module's jump table. If an alias was pointing to such a function definition LowerTypeTests would fail because the alias would be left without a definition to point to. This change 1) emits information about aliases to the ThinLTO summary, 2) replaces aliases pointing to function definitions that are moved to the merged module with function declarations, and 3) re-emits those aliases in the merged module pointing to the correct function definitions. The patch does not correctly fix all possible mis-uses of aliases in LowerTypeTests. For example, it does not handle aliases with a different type from the pointed to function. The addition of alias data increases the size of Chrome build artifacts by less than 1%. Reviewers: pcc Reviewed By: pcc Subscribers: mehdi_amini, eraman, mgrang, llvm-commits, eugenis, kcc Differential Revision: https://reviews.llvm.org/D41741 llvm-svn: 322139
* Avoid int to string conversion in Twine or raw_ostream contexts.Benjamin Kramer2017-12-281-2/+1
| | | | | | Some output changes from uppercase hex to lowercase hex, no other functionality change intended. llvm-svn: 321526
* Remove redundant includes from lib/Transforms.Michael Zolotukhin2017-12-131-1/+0
| | | | llvm-svn: 320628
* ThinLTOBitcodeWriter: Try harder to discard unused references to the merged ↵Peter Collingbourne2017-11-301-3/+11
| | | | | | | | | | | | | | | | | | | module. If the thin module has no references to an internal global in the merged module, we need to make sure to preserve that property if the global is a member of a comdat group, as otherwise promotion can end up adding global symbols to the comdat, which is not allowed. This situation can arise if the external global in the thin module has dead constant users, which would cause use_empty() to return false and would cause us to try to promote it. To prevent this from happening, discard the dead constant users before asking whether a global is empty. Differential Revision: https://reviews.llvm.org/D40593 llvm-svn: 319494
* ThinLTO Minimized Bitcode File Size ReductionHaojie Wang2017-07-211-13/+9
| | | | | | | | | | | | | | Summary: Currently the ThinLTO minimized bitcode file only strip the debug info, but there is still a lot of information in the minimized bit code file that will be not used for thin linker. In this patch, most of the extra information is striped to reduce the minimized bitcode file. Now only ModuleVersion, ModuleInfo, ModuleGlobalValueSummary, ModuleHash, Symtab and Strtab are left. Now the minimized bitcode file size is reduced to 15%-30% of the debug info stripped bitcode file size. Reviewers: danielcdh, tejohnson, pcc Reviewed By: pcc Subscribers: mehdi_amini, aprantl, inglorion, eraman, llvm-commits Differential Revision: https://reviews.llvm.org/D35334 llvm-svn: 308760
* ThinLTOBitcodeWriter: Do not rewrite intrinsic functions when splitting modules.Peter Collingbourne2017-07-191-1/+3
| | | | | | | | Changing the type of an intrinsic may invalidate the IR. Differential Revision: https://reviews.llvm.org/D35593 llvm-svn: 308500
* [PM/ThinLTO] Fix PR33536, a bug where the ThinLTO bitcode writer wasChandler Carruth2017-07-111-1/+2
| | | | | | | | | | | | | querying for analysis results on a function declaration rather than a definition. The only reason this worked previously is by chance -- because the way we got alias analysis results with the legacy PM, we happened to not compute a dominator tree and so we happened to not hit an assert even though it didn't make any real sense. Now we bail out before trying to compute alias analysis so that we don't hit these asserts. llvm-svn: 307625
* Bitcode: Write the irsymtab to disk.Peter Collingbourne2017-06-271-0/+2
| | | | | | Differential Revision: https://reviews.llvm.org/D33973 llvm-svn: 306487
* [cfi] CFI-ICall for ThinLTO.Evgeniy Stepanov2017-06-161-7/+43
| | | | | | | | Implement ControlFlowIntegrity for indirect function calls in ThinLTO. Design follows the RFC in llvm-dev, see https://groups.google.com/d/msg/llvm-dev/MgUlaphu4Qc/kywu0AqjAQAJ llvm-svn: 305533
* Write summaries for merged modules when splitting modules for ThinLTO.Peter Collingbourne2017-06-081-2/+10
| | | | | | | | | This is to prepare to allow for dead stripping of globals in the merged modules. Differential Revision: https://reviews.llvm.org/D33921 llvm-svn: 305027
* [ThinLTO] Migrate ThinLTOBitcodeWriter to the new PM.Tim Shen2017-06-011-7/+13
| | | | | | | | | | | | Summary: Also see D33429 for other ThinLTO + New PM related changes. Reviewers: davide, chandlerc, tejohnson Subscribers: mehdi_amini, Prazek, cfe-commits, inglorion, llvm-commits, eraman Differential Revision: https://reviews.llvm.org/D33525 llvm-svn: 304378
* Remove spurious cast of nullptr. NFC.Serge Guelton2017-05-111-1/+1
| | | | | | Conversion rules allow automatic casting of nullptr to any pointer type. llvm-svn: 302780
* Ensure non-null ProfileSummaryInfo passed to ModuleSummaryIndex builderTeresa Johnson2017-05-101-1/+3
| | | | | | | | | | | | This fixes a ubsan bot failure after r302597, which made getProfileCount non-static, but ended up invoking it on a null ProfileSummaryInfo object in some cases from buildModuleSummaryIndex. Most testing passed because the non-static getProfileCount currently doesn't access any member variables, but I found this when testing a follow on patch (D32877) that adds a member variable access. llvm-svn: 302705
* [asan] Fix dead stripping of globals on Linux.Evgeniy Stepanov2017-04-271-33/+2
| | | | | | | | | | | | | | | | | | | | | | Use a combination of !associated, comdat, @llvm.compiler.used and custom sections to allow dead stripping of globals and their asan metadata. Sometimes. Currently this works on LLD, which supports SHF_LINK_ORDER with sh_link pointing to the associated section. This also works on BFD, which seems to treat comdats as all-or-nothing with respect to linker GC. There is a weird quirk where the "first" global in each link is never GC-ed because of the section symbols. At this moment it does not work on Gold (as in the globals are never stripped). This is a second re-land of r298158. This time, this feature is limited to -fdata-sections builds. llvm-svn: 301587
* Bitcode: Add a string table to the bitcode format.Peter Collingbourne2017-04-171-0/+2
| | | | | | | | | | | | | | | | | | | | | | | Add a top-level STRTAB block containing a string table blob, and start storing strings for module codes FUNCTION, GLOBALVAR, ALIAS, IFUNC and COMDAT in the string table. This change allows us to share names between globals and comdats as well as between modules, and improves the efficiency of loading bitcode files by no longer using a bit encoding for symbol names. Once we start writing the irsymtab to the bitcode file we will also be able to share strings between it and the module. On my machine, link time for Chromium for Linux with ThinLTO decreases by about 7% for no-op incremental builds or about 1% for full builds. Total bitcode file size decreases by about 3%. As discussed on llvm-dev: http://lists.llvm.org/pipermail/llvm-dev/2017-April/111732.html Differential Revision: https://reviews.llvm.org/D31838 llvm-svn: 300464
* ThinLTOBitcodeWriter: keep comdats together, rename if leader is renamedBob Haarman2017-04-121-6/+33
| | | | | | | | | | | | | | | | | | | Summary: COFF requires that every comdat contain a symbol with the same name as the comdat. ThinLTOBitcodeWriter renames symbols, which may cause this requirement to be violated. This change avoids such violations by renaming comdats if their leaders are renamed. It also keeps comdats together when splitting modules. Reviewers: pcc, mehdi_amini, tejohnson Reviewed By: pcc Subscribers: rnk, Prazek, llvm-commits Differential Revision: https://reviews.llvm.org/D31963 llvm-svn: 300019
* Revert "[asan] Fix dead stripping of globals on Linux."Evgeniy Stepanov2017-04-101-2/+33
| | | | | | This reverts commit r299697, which caused a big increase in object file size. llvm-svn: 299879
* [asan] Fix dead stripping of globals on Linux.Evgeniy Stepanov2017-04-061-33/+2
| | | | | | | | | | | | | | | | | | | | | | | Use a combination of !associated, comdat, @llvm.compiler.used and custom sections to allow dead stripping of globals and their asan metadata. Sometimes. Currently this works on LLD, which supports SHF_LINK_ORDER with sh_link pointing to the associated section. This also works on BFD, which seems to treat comdats as all-or-nothing with respect to linker GC. There is a weird quirk where the "first" global in each link is never GC-ed because of the section symbols. At this moment it does not work on Gold (as in the globals are never stripped). This is a re-land of r298158 rebased on D31358. This time, asan.module_ctor is put in a comdat as well to avoid quadratic behavior in Gold. llvm-svn: 299697
* ThinLTOBitcodeWriter: handle aliases first in filterModuleBob Haarman2017-04-051-20/+20
| | | | | | | | | | | | | | Summary: This change fixes a "local linkage requires default visibility" assert when attempting to build LLVM with ThinLTO on Windows. Reviewers: pcc, tejohnson, mehdi_amini Reviewed By: pcc Subscribers: llvm-commits, Prazek Differential Revision: https://reviews.llvm.org/D31632 llvm-svn: 299491
* ThinLTOBitcodeWriter: Use Module::global_values(). NFCI.Peter Collingbourne2017-03-301-25/+7
| | | | llvm-svn: 299132
* [ThinLTO] Add support for emitting minimized bitcode for thin linkTeresa Johnson2017-03-231-17/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: The cumulative size of the bitcode files for a very large application can be huge, particularly with -g. In a distributed build environment, all of these files must be sent to the remote build node that performs the thin link step, and this can exceed size limits. The thin link actually only needs the summary along with a bitcode symbol table. Until we have a proper bitcode symbol table, simply stripping the debug metadata results in significant size reduction. Add support for an option to additionally emit minimized bitcode modules, just for use in the thin link step, which for now just strips all debug metadata. I plan to add a cc1 option so this can be invoked easily during the compile step. However, care must be taken to ensure that these minimized thin link bitcode files produce the same index as with the original bitcode files, as these original bitcode files will be used in the backends. Specifically: 1) The module hash used for caching is typically produced by hashing the written bitcode, and we want to include the hash that would correspond to the original bitcode file. This is because we want to ensure that changes in the stripped portions affect caching. Added plumbing to emit the same module hash in the minimized thin link bitcode file. 2) The module paths in the index are constructed from the module ID of each thin linked bitcode, and typically is automatically generated from the input file path. This is the path used for finding the modules to import from, and obviously we need this to point to the original bitcode files. Added gold-plugin support to take a suffix replacement during the thin link that is used to override the identifier on the MemoryBufferRef constructed from the loaded thin link bitcode file. The assumption is that the build system can specify that the minimized bitcode file has a name that is similar but uses a different suffix (e.g. out.thinlink.bc instead of out.o). Added various tests to ensure that we get identical index files out of the thin link step. Reviewers: mehdi_amini, pcc Subscribers: Prazek, llvm-commits Differential Revision: https://reviews.llvm.org/D31027 llvm-svn: 298638
* Revert r298158.Evgeniy Stepanov2017-03-201-2/+42
| | | | | | | | Revert "[asan] Fix dead stripping of globals on Linux." OOM in gold linker. llvm-svn: 298288
* [asan] Fix dead stripping of globals on Linux.Evgeniy Stepanov2017-03-171-42/+2
| | | | | | | | | | | | | | | | | | | | | Use a combination of !associated, comdat, @llvm.compiler.used and custom sections to allow dead stripping of globals and their asan metadata. Sometimes. Currently this works on LLD, which supports SHF_LINK_ORDER with sh_link pointing to the associated section. This also works on BFD, which seems to treat comdats as all-or-nothing with respect to linker GC. There is a weird quirk where the "first" global in each link is never GC-ed because of the section symbols. At this moment it does not work on Gold (as in the globals are never stripped). Differential Revision: https://reviews.llvm.org/D30121 llvm-svn: 298158
* ThinLTOBitcodeWriter: Do not follow operand edges of type GlobalValue when ↵Peter Collingbourne2017-03-021-0/+2
| | | | | | | | | | | | looking for virtual functions. Such edges may otherwise result in infinite recursion if a pointer to a vtable is reachable from the vtable itself. This can happen in practice if a TU defines the ABI types used to implement RTTI, and is itself compiled with RTTI. Fixes PR32121. llvm-svn: 296839
* ThinLTOBitcodeWriter: Write available_externally copies of VCP eligible ↵Peter Collingbourne2017-02-141-13/+79
| | | | | | | | functions to merged module. Differential Revision: https://reviews.llvm.org/D29701 llvm-svn: 295021
* ThinLTOBitcodeWriter: Strip debug info from merged module.Peter Collingbourne2017-02-081-0/+2
| | | | | | | | | | This module will contain nothing but vtable definitions and (soon) available_externally function definitions, so there is no point in keeping debug info in the module. Differential Revision: https://reviews.llvm.org/D28913 llvm-svn: 294511
* ThinLTOBitcodeWriter: Clear comdats on filtered globals.Peter Collingbourne2017-01-181-0/+2
| | | | | | Differential Revision: https://reviews.llvm.org/D28839 llvm-svn: 292431
* Apply clang-tidy's performance-unnecessary-value-param to LLVM.Benjamin Kramer2017-01-131-1/+1
| | | | | | | With some minor manual fixes for using function_ref instead of std::function. No functional change intended. llvm-svn: 291904
* IPO: Introduce ThinLTOBitcodeWriter pass.Peter Collingbourne2016-12-161-0/+344
This pass prepares a module containing type metadata for ThinLTO by splitting it into regular and thin LTO parts if possible, and writing both parts to a multi-module bitcode file. Modules that do not contain type metadata are written unmodified as a single module. All globals with type metadata are added to the regular LTO module, and the rest are added to the thin LTO module. Differential Revision: https://reviews.llvm.org/D27324 llvm-svn: 289899
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