Author: Mingming Liu Date: 2024-09-08T16:45:07-07:00 New Revision: 2b33fbee3f36344786fa63b189387c3bd90c4c3f
URL: https://github.com/llvm/llvm-project/commit/2b33fbee3f36344786fa63b189387c3bd90c4c3f DIFF: https://github.com/llvm/llvm-project/commit/2b33fbee3f36344786fa63b189387c3bd90c4c3f.diff LOG: Revert "[NFCI][LTO][lld] Optimize away symbol copies within LTO global resolu…" This reverts commit 9ade4e2646bd52b49e50c1648301da65de90ffa9. Added: Modified: lld/ELF/InputFiles.cpp lld/ELF/LTO.cpp llvm/include/llvm/LTO/Config.h llvm/include/llvm/LTO/LTO.h llvm/lib/LTO/LTO.cpp Removed: ################################################################################ diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp index da69c4882ead21..1570adf1370930 100644 --- a/lld/ELF/InputFiles.cpp +++ b/lld/ELF/InputFiles.cpp @@ -1804,10 +1804,6 @@ void BitcodeFile::parseLazy() { auto *sym = symtab.insert(unique_saver().save(irSym.getName())); sym->resolve(LazySymbol{*this}); symbols[i] = sym; - } else { - // Keep copies of per-module undefined symbols for LTO::GlobalResolutions - // usage. - unique_saver().save(irSym.getName()); } } diff --git a/lld/ELF/LTO.cpp b/lld/ELF/LTO.cpp index f339f1c2c0ec21..935d0a9eab9ee0 100644 --- a/lld/ELF/LTO.cpp +++ b/lld/ELF/LTO.cpp @@ -135,7 +135,6 @@ static lto::Config createConfig() { config->ltoValidateAllVtablesHaveTypeInfos; c.AllVtablesHaveTypeInfos = ctx.ltoAllVtablesHaveTypeInfos; c.AlwaysEmitRegularLTOObj = !config->ltoObjPath.empty(); - c.KeepSymbolNameCopies = false; for (const llvm::StringRef &name : config->thinLTOModulesToCompile) c.ThinLTOModulesToCompile.emplace_back(name); diff --git a/llvm/include/llvm/LTO/Config.h b/llvm/include/llvm/LTO/Config.h index a49cce9f30e20c..482b6e55a19d35 100644 --- a/llvm/include/llvm/LTO/Config.h +++ b/llvm/include/llvm/LTO/Config.h @@ -88,11 +88,6 @@ struct Config { /// want to know a priori all possible output files. bool AlwaysEmitRegularLTOObj = false; - /// If true, the LTO instance creates copies of the symbol names for LTO::run. - /// The lld linker uses string saver to keep symbol names alive and doesn't - /// need to create copies, so it can set this field to false. - bool KeepSymbolNameCopies = true; - /// Allows non-imported definitions to get the potentially more constraining /// visibility from the prevailing definition. FromPrevailing is the default /// because it works for many binary formats. ELF can use the more optimized diff --git a/llvm/include/llvm/LTO/LTO.h b/llvm/include/llvm/LTO/LTO.h index 782f37dc8d4404..949e80a43f0e88 100644 --- a/llvm/include/llvm/LTO/LTO.h +++ b/llvm/include/llvm/LTO/LTO.h @@ -15,9 +15,6 @@ #ifndef LLVM_LTO_LTO_H #define LLVM_LTO_LTO_H -#include <memory> - -#include "llvm/ADT/DenseMap.h" #include "llvm/ADT/MapVector.h" #include "llvm/ADT/StringMap.h" #include "llvm/Bitcode/BitcodeReader.h" @@ -26,7 +23,6 @@ #include "llvm/Object/IRSymtab.h" #include "llvm/Support/Caching.h" #include "llvm/Support/Error.h" -#include "llvm/Support/StringSaver.h" #include "llvm/Support/thread.h" #include "llvm/Transforms/IPO/FunctionAttrs.h" #include "llvm/Transforms/IPO/FunctionImport.h" @@ -407,19 +403,10 @@ class LTO { }; }; - // GlobalResolutionSymbolSaver allocator. - std::unique_ptr<llvm::BumpPtrAllocator> Alloc; - - // Symbol saver for global resolution map. - std::unique_ptr<llvm::StringSaver> GlobalResolutionSymbolSaver; - // Global mapping from mangled symbol names to resolutions. - // Make this an unique_ptr to guard against accessing after it has been reset + // Make this an optional to guard against accessing after it has been reset // (to reduce memory after we're done with it). - std::unique_ptr<llvm::DenseMap<StringRef, GlobalResolution>> - GlobalResolutions; - - void releaseGlobalResolutionsMemory(); + std::optional<StringMap<GlobalResolution>> GlobalResolutions; void addModuleToGlobalRes(ArrayRef<InputFile::Symbol> Syms, ArrayRef<SymbolResolution> Res, unsigned Partition, diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp index 5d9a5cbd18f156..68072563cb33d6 100644 --- a/llvm/lib/LTO/LTO.cpp +++ b/llvm/lib/LTO/LTO.cpp @@ -77,10 +77,6 @@ cl::opt<bool> EnableLTOInternalization( "enable-lto-internalization", cl::init(true), cl::Hidden, cl::desc("Enable global value internalization in LTO")); -static cl::opt<bool> - LTOKeepSymbolCopies("lto-keep-symbol-copies", cl::init(false), cl::Hidden, - cl::desc("Keep copies of symbols in LTO indexing")); - /// Indicate we are linking with an allocator that supports hot/cold operator /// new interfaces. extern cl::opt<bool> SupportsHotColdNew; @@ -591,14 +587,8 @@ LTO::LTO(Config Conf, ThinBackend Backend, : Conf(std::move(Conf)), RegularLTO(ParallelCodeGenParallelismLevel, this->Conf), ThinLTO(std::move(Backend)), - GlobalResolutions( - std::make_unique<DenseMap<StringRef, GlobalResolution>>()), - LTOMode(LTOMode) { - if (Conf.KeepSymbolNameCopies || LTOKeepSymbolCopies) { - Alloc = std::make_unique<BumpPtrAllocator>(); - GlobalResolutionSymbolSaver = std::make_unique<llvm::StringSaver>(*Alloc); - } -} + GlobalResolutions(std::make_optional<StringMap<GlobalResolution>>()), + LTOMode(LTOMode) {} // Requires a destructor for MapVector<BitcodeModule>. LTO::~LTO() = default; @@ -616,12 +606,7 @@ void LTO::addModuleToGlobalRes(ArrayRef<InputFile::Symbol> Syms, assert(ResI != ResE); SymbolResolution Res = *ResI++; - StringRef SymbolName = Sym.getName(); - // Keep copies of symbols if the client of LTO says so. - if (GlobalResolutionSymbolSaver && !GlobalResolutions->contains(SymbolName)) - SymbolName = GlobalResolutionSymbolSaver->save(SymbolName); - - auto &GlobalRes = (*GlobalResolutions)[SymbolName]; + auto &GlobalRes = (*GlobalResolutions)[Sym.getName()]; GlobalRes.UnnamedAddr &= Sym.isUnnamedAddr(); if (Res.Prevailing) { assert(!GlobalRes.Prevailing && @@ -675,14 +660,6 @@ void LTO::addModuleToGlobalRes(ArrayRef<InputFile::Symbol> Syms, } } -void LTO::releaseGlobalResolutionsMemory() { - // Release GlobalResolutions dense-map itself. - GlobalResolutions.reset(); - // Release the string saver memory. - GlobalResolutionSymbolSaver.reset(); - Alloc.reset(); -} - static void writeToResolutionFile(raw_ostream &OS, InputFile *Input, ArrayRef<SymbolResolution> Res) { StringRef Path = Input->getName(); @@ -1794,7 +1771,7 @@ Error LTO::runThinLTO(AddStreamFn AddStream, FileCache Cache, // are no further accesses. We specifically want to do this before computing // cross module importing, which adds to peak memory via the computed import // and export lists. - releaseGlobalResolutionsMemory(); + GlobalResolutions.reset(); if (Conf.OptLevel > 0) ComputeCrossModuleImport(ThinLTO.CombinedIndex, ModuleToDefinedGVSummaries, _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
