| //===- llvm-link.cpp - Low-level LLVM linker ------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This utility may be invoked in the following manner: |
| // llvm-link a.bc b.bc c.bc -o x.bc |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/Bitcode/BitcodeReader.h" |
| #include "llvm/Bitcode/BitcodeWriter.h" |
| #include "llvm/IR/AutoUpgrade.h" |
| #include "llvm/IR/DiagnosticInfo.h" |
| #include "llvm/IR/DiagnosticPrinter.h" |
| #include "llvm/IR/LLVMContext.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/IR/ModuleSummaryIndex.h" |
| #include "llvm/IR/Verifier.h" |
| #include "llvm/IRReader/IRReader.h" |
| #include "llvm/Linker/Linker.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/FileSystem.h" |
| #include "llvm/Support/InitLLVM.h" |
| #include "llvm/Support/Path.h" |
| #include "llvm/Support/SourceMgr.h" |
| #include "llvm/Support/SystemUtils.h" |
| #include "llvm/Support/ToolOutputFile.h" |
| #include "llvm/Support/WithColor.h" |
| #include "llvm/Transforms/IPO/FunctionImport.h" |
| #include "llvm/Transforms/IPO/Internalize.h" |
| #include "llvm/Transforms/Utils/FunctionImportUtils.h" |
| |
| #include <memory> |
| #include <utility> |
| using namespace llvm; |
| |
| static cl::list<std::string> |
| InputFilenames(cl::Positional, cl::OneOrMore, |
| cl::desc("<input bitcode files>")); |
| |
| static cl::list<std::string> OverridingInputs( |
| "override", cl::ZeroOrMore, cl::value_desc("filename"), |
| cl::desc( |
| "input bitcode file which can override previously defined symbol(s)")); |
| |
| // Option to simulate function importing for testing. This enables using |
| // llvm-link to simulate ThinLTO backend processes. |
| static cl::list<std::string> Imports( |
| "import", cl::ZeroOrMore, cl::value_desc("function:filename"), |
| cl::desc("Pair of function name and filename, where function should be " |
| "imported from bitcode in filename")); |
| |
| // Option to support testing of function importing. The module summary |
| // must be specified in the case were we request imports via the -import |
| // option, as well as when compiling any module with functions that may be |
| // exported (imported by a different llvm-link -import invocation), to ensure |
| // consistent promotion and renaming of locals. |
| static cl::opt<std::string> |
| SummaryIndex("summary-index", cl::desc("Module summary index filename"), |
| cl::init(""), cl::value_desc("filename")); |
| |
| static cl::opt<std::string> |
| OutputFilename("o", cl::desc("Override output filename"), cl::init("-"), |
| cl::value_desc("filename")); |
| |
| static cl::opt<bool> |
| Internalize("internalize", cl::desc("Internalize linked symbols")); |
| |
| static cl::opt<bool> |
| DisableDITypeMap("disable-debug-info-type-map", |
| cl::desc("Don't use a uniquing type map for debug info")); |
| |
| static cl::opt<bool> |
| OnlyNeeded("only-needed", cl::desc("Link only needed symbols")); |
| |
| static cl::opt<bool> |
| Force("f", cl::desc("Enable binary output on terminals")); |
| |
| static cl::opt<bool> |
| DisableLazyLoad("disable-lazy-loading", |
| cl::desc("Disable lazy module loading")); |
| |
| static cl::opt<bool> |
| OutputAssembly("S", cl::desc("Write output as LLVM assembly"), cl::Hidden); |
| |
| static cl::opt<bool> |
| Verbose("v", cl::desc("Print information about actions taken")); |
| |
| static cl::opt<bool> |
| DumpAsm("d", cl::desc("Print assembly as linked"), cl::Hidden); |
| |
| static cl::opt<bool> |
| SuppressWarnings("suppress-warnings", cl::desc("Suppress all linking warnings"), |
| cl::init(false)); |
| |
| static cl::opt<bool> PreserveBitcodeUseListOrder( |
| "preserve-bc-uselistorder", |
| cl::desc("Preserve use-list order when writing LLVM bitcode."), |
| cl::init(true), cl::Hidden); |
| |
| static cl::opt<bool> PreserveAssemblyUseListOrder( |
| "preserve-ll-uselistorder", |
| cl::desc("Preserve use-list order when writing LLVM assembly."), |
| cl::init(false), cl::Hidden); |
| |
| static ExitOnError ExitOnErr; |
| |
| // Read the specified bitcode file in and return it. This routine searches the |
| // link path for the specified file to try to find it... |
| // |
| static std::unique_ptr<Module> loadFile(const char *argv0, |
| const std::string &FN, |
| LLVMContext &Context, |
| bool MaterializeMetadata = true) { |
| SMDiagnostic Err; |
| if (Verbose) |
| errs() << "Loading '" << FN << "'\n"; |
| std::unique_ptr<Module> Result; |
| if (DisableLazyLoad) |
| Result = parseIRFile(FN, Err, Context); |
| else |
| Result = getLazyIRFileModule(FN, Err, Context, !MaterializeMetadata); |
| |
| if (!Result) { |
| Err.print(argv0, errs()); |
| return nullptr; |
| } |
| |
| if (MaterializeMetadata) { |
| ExitOnErr(Result->materializeMetadata()); |
| UpgradeDebugInfo(*Result); |
| } |
| |
| return Result; |
| } |
| |
| namespace { |
| |
| /// Helper to load on demand a Module from file and cache it for subsequent |
| /// queries during function importing. |
| class ModuleLazyLoaderCache { |
| /// Cache of lazily loaded module for import. |
| StringMap<std::unique_ptr<Module>> ModuleMap; |
| |
| /// Retrieve a Module from the cache or lazily load it on demand. |
| std::function<std::unique_ptr<Module>(const char *argv0, |
| const std::string &FileName)> |
| createLazyModule; |
| |
| public: |
| /// Create the loader, Module will be initialized in \p Context. |
| ModuleLazyLoaderCache(std::function<std::unique_ptr<Module>( |
| const char *argv0, const std::string &FileName)> |
| createLazyModule) |
| : createLazyModule(std::move(createLazyModule)) {} |
| |
| /// Retrieve a Module from the cache or lazily load it on demand. |
| Module &operator()(const char *argv0, const std::string &FileName); |
| |
| std::unique_ptr<Module> takeModule(const std::string &FileName) { |
| auto I = ModuleMap.find(FileName); |
| assert(I != ModuleMap.end()); |
| std::unique_ptr<Module> Ret = std::move(I->second); |
| ModuleMap.erase(I); |
| return Ret; |
| } |
| }; |
| |
| // Get a Module for \p FileName from the cache, or load it lazily. |
| Module &ModuleLazyLoaderCache::operator()(const char *argv0, |
| const std::string &Identifier) { |
| auto &Module = ModuleMap[Identifier]; |
| if (!Module) |
| Module = createLazyModule(argv0, Identifier); |
| return *Module; |
| } |
| } // anonymous namespace |
| |
| namespace { |
| struct LLVMLinkDiagnosticHandler : public DiagnosticHandler { |
| bool handleDiagnostics(const DiagnosticInfo &DI) override { |
| unsigned Severity = DI.getSeverity(); |
| switch (Severity) { |
| case DS_Error: |
| WithColor::error(); |
| break; |
| case DS_Warning: |
| if (SuppressWarnings) |
| return true; |
| WithColor::warning(); |
| break; |
| case DS_Remark: |
| case DS_Note: |
| llvm_unreachable("Only expecting warnings and errors"); |
| } |
| |
| DiagnosticPrinterRawOStream DP(errs()); |
| DI.print(DP); |
| errs() << '\n'; |
| return true; |
| } |
| }; |
| } |
| |
| /// Import any functions requested via the -import option. |
| static bool importFunctions(const char *argv0, Module &DestModule) { |
| if (SummaryIndex.empty()) |
| return true; |
| std::unique_ptr<ModuleSummaryIndex> Index = |
| ExitOnErr(llvm::getModuleSummaryIndexForFile(SummaryIndex)); |
| |
| // Map of Module -> List of globals to import from the Module |
| FunctionImporter::ImportMapTy ImportList; |
| |
| auto ModuleLoader = [&DestModule](const char *argv0, |
| const std::string &Identifier) { |
| return loadFile(argv0, Identifier, DestModule.getContext(), false); |
| }; |
| |
| ModuleLazyLoaderCache ModuleLoaderCache(ModuleLoader); |
| for (const auto &Import : Imports) { |
| // Identify the requested function and its bitcode source file. |
| size_t Idx = Import.find(':'); |
| if (Idx == std::string::npos) { |
| errs() << "Import parameter bad format: " << Import << "\n"; |
| return false; |
| } |
| std::string FunctionName = Import.substr(0, Idx); |
| std::string FileName = Import.substr(Idx + 1, std::string::npos); |
| |
| // Load the specified source module. |
| auto &SrcModule = ModuleLoaderCache(argv0, FileName); |
| |
| if (verifyModule(SrcModule, &errs())) { |
| errs() << argv0 << ": " << FileName; |
| WithColor::error() << "input module is broken!\n"; |
| return false; |
| } |
| |
| Function *F = SrcModule.getFunction(FunctionName); |
| if (!F) { |
| errs() << "Ignoring import request for non-existent function " |
| << FunctionName << " from " << FileName << "\n"; |
| continue; |
| } |
| // We cannot import weak_any functions without possibly affecting the |
| // order they are seen and selected by the linker, changing program |
| // semantics. |
| if (F->hasWeakAnyLinkage()) { |
| errs() << "Ignoring import request for weak-any function " << FunctionName |
| << " from " << FileName << "\n"; |
| continue; |
| } |
| |
| if (Verbose) |
| errs() << "Importing " << FunctionName << " from " << FileName << "\n"; |
| |
| auto &Entry = ImportList[FileName]; |
| Entry.insert(F->getGUID()); |
| } |
| auto CachedModuleLoader = [&](StringRef Identifier) { |
| return ModuleLoaderCache.takeModule(Identifier); |
| }; |
| FunctionImporter Importer(*Index, CachedModuleLoader); |
| ExitOnErr(Importer.importFunctions(DestModule, ImportList)); |
| |
| return true; |
| } |
| |
| static bool linkFiles(const char *argv0, LLVMContext &Context, Linker &L, |
| const cl::list<std::string> &Files, |
| unsigned Flags) { |
| // Filter out flags that don't apply to the first file we load. |
| unsigned ApplicableFlags = Flags & Linker::Flags::OverrideFromSrc; |
| // Similar to some flags, internalization doesn't apply to the first file. |
| bool InternalizeLinkedSymbols = false; |
| for (const auto &File : Files) { |
| std::unique_ptr<Module> M = loadFile(argv0, File, Context); |
| if (!M.get()) { |
| errs() << argv0 << ": "; |
| WithColor::error() << " loading file '" << File << "'\n"; |
| return false; |
| } |
| |
| // Note that when ODR merging types cannot verify input files in here When |
| // doing that debug metadata in the src module might already be pointing to |
| // the destination. |
| if (DisableDITypeMap && verifyModule(*M, &errs())) { |
| errs() << argv0 << ": " << File << ": "; |
| WithColor::error() << "input module is broken!\n"; |
| return false; |
| } |
| |
| // If a module summary index is supplied, load it so linkInModule can treat |
| // local functions/variables as exported and promote if necessary. |
| if (!SummaryIndex.empty()) { |
| std::unique_ptr<ModuleSummaryIndex> Index = |
| ExitOnErr(llvm::getModuleSummaryIndexForFile(SummaryIndex)); |
| |
| // Conservatively mark all internal values as promoted, since this tool |
| // does not do the ThinLink that would normally determine what values to |
| // promote. |
| for (auto &I : *Index) { |
| for (auto &S : I.second.SummaryList) { |
| if (GlobalValue::isLocalLinkage(S->linkage())) |
| S->setLinkage(GlobalValue::ExternalLinkage); |
| } |
| } |
| |
| // Promotion |
| if (renameModuleForThinLTO(*M, *Index)) |
| return true; |
| } |
| |
| if (Verbose) |
| errs() << "Linking in '" << File << "'\n"; |
| |
| bool Err = false; |
| if (InternalizeLinkedSymbols) { |
| Err = L.linkInModule( |
| std::move(M), ApplicableFlags, [](Module &M, const StringSet<> &GVS) { |
| internalizeModule(M, [&GVS](const GlobalValue &GV) { |
| return !GV.hasName() || (GVS.count(GV.getName()) == 0); |
| }); |
| }); |
| } else { |
| Err = L.linkInModule(std::move(M), ApplicableFlags); |
| } |
| |
| if (Err) |
| return false; |
| |
| // Internalization applies to linking of subsequent files. |
| InternalizeLinkedSymbols = Internalize; |
| |
| // All linker flags apply to linking of subsequent files. |
| ApplicableFlags = Flags; |
| } |
| |
| return true; |
| } |
| |
| int main(int argc, char **argv) { |
| InitLLVM X(argc, argv); |
| ExitOnErr.setBanner(std::string(argv[0]) + ": "); |
| |
| LLVMContext Context; |
| Context.setDiagnosticHandler( |
| llvm::make_unique<LLVMLinkDiagnosticHandler>(), true); |
| cl::ParseCommandLineOptions(argc, argv, "llvm linker\n"); |
| |
| if (!DisableDITypeMap) |
| Context.enableDebugTypeODRUniquing(); |
| |
| auto Composite = make_unique<Module>("llvm-link", Context); |
| Linker L(*Composite); |
| |
| unsigned Flags = Linker::Flags::None; |
| if (OnlyNeeded) |
| Flags |= Linker::Flags::LinkOnlyNeeded; |
| |
| // First add all the regular input files |
| if (!linkFiles(argv[0], Context, L, InputFilenames, Flags)) |
| return 1; |
| |
| // Next the -override ones. |
| if (!linkFiles(argv[0], Context, L, OverridingInputs, |
| Flags | Linker::Flags::OverrideFromSrc)) |
| return 1; |
| |
| // Import any functions requested via -import |
| if (!importFunctions(argv[0], *Composite)) |
| return 1; |
| |
| if (DumpAsm) |
| errs() << "Here's the assembly:\n" << *Composite; |
| |
| std::error_code EC; |
| ToolOutputFile Out(OutputFilename, EC, sys::fs::F_None); |
| if (EC) { |
| WithColor::error() << EC.message() << '\n'; |
| return 1; |
| } |
| |
| if (verifyModule(*Composite, &errs())) { |
| errs() << argv[0] << ": "; |
| WithColor::error() << "linked module is broken!\n"; |
| return 1; |
| } |
| |
| if (Verbose) |
| errs() << "Writing bitcode...\n"; |
| if (OutputAssembly) { |
| Composite->print(Out.os(), nullptr, PreserveAssemblyUseListOrder); |
| } else if (Force || !CheckBitcodeOutputToConsole(Out.os(), true)) |
| WriteBitcodeToFile(*Composite, Out.os(), PreserveBitcodeUseListOrder); |
| |
| // Declare success. |
| Out.keep(); |
| |
| return 0; |
| } |