| //===- llvm-link.cpp - Low-level LLVM linker ------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This utility may be invoked in the following manner: |
| // llvm-link a.bc b.bc c.bc -o x.bc |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Linker/Linker.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/Bitcode/ReaderWriter.h" |
| #include "llvm/IR/AutoUpgrade.h" |
| #include "llvm/IR/DiagnosticInfo.h" |
| #include "llvm/IR/DiagnosticPrinter.h" |
| #include "llvm/IR/FunctionInfo.h" |
| #include "llvm/IR/LLVMContext.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/IR/Verifier.h" |
| #include "llvm/IRReader/IRReader.h" |
| #include "llvm/Object/FunctionIndexObjectFile.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/FileSystem.h" |
| #include "llvm/Support/ManagedStatic.h" |
| #include "llvm/Support/Path.h" |
| #include "llvm/Support/PrettyStackTrace.h" |
| #include "llvm/Support/Signals.h" |
| #include "llvm/Support/SourceMgr.h" |
| #include "llvm/Support/SystemUtils.h" |
| #include "llvm/Support/ToolOutputFile.h" |
| #include <memory> |
| 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 function index |
| // 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> FunctionIndex("functionindex", |
| cl::desc("Function 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> |
| 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> |
| 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> |
| PreserveModules("preserve-modules", |
| cl::desc("Preserve linked modules for testing")); |
| |
| 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); |
| |
| // 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 = |
| getLazyIRFileModule(FN, Err, Context, !MaterializeMetadata); |
| if (!Result) |
| Err.print(argv0, errs()); |
| |
| if (MaterializeMetadata) { |
| Result->materializeMetadata(); |
| UpgradeDebugInfo(*Result); |
| } |
| |
| return Result; |
| } |
| |
| static void diagnosticHandler(const DiagnosticInfo &DI) { |
| unsigned Severity = DI.getSeverity(); |
| switch (Severity) { |
| case DS_Error: |
| errs() << "ERROR: "; |
| break; |
| case DS_Warning: |
| if (SuppressWarnings) |
| return; |
| errs() << "WARNING: "; |
| break; |
| case DS_Remark: |
| case DS_Note: |
| llvm_unreachable("Only expecting warnings and errors"); |
| } |
| |
| DiagnosticPrinterRawOStream DP(errs()); |
| DI.print(DP); |
| errs() << '\n'; |
| } |
| |
| static void diagnosticHandlerWithContext(const DiagnosticInfo &DI, void *C) { |
| diagnosticHandler(DI); |
| } |
| |
| /// Import any functions requested via the -import option. |
| static bool importFunctions(const char *argv0, LLVMContext &Context, |
| Linker &L) { |
| StringMap<std::unique_ptr<DenseMap<unsigned, MDNode *>>> |
| ModuleToTempMDValsMap; |
| 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. |
| std::unique_ptr<Module> M = loadFile(argv0, FileName, Context, false); |
| if (!M.get()) { |
| errs() << argv0 << ": error loading file '" << FileName << "'\n"; |
| return false; |
| } |
| |
| if (verifyModule(*M, &errs())) { |
| errs() << argv0 << ": " << FileName |
| << ": error: input module is broken!\n"; |
| return false; |
| } |
| |
| Function *F = M->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"; |
| |
| std::unique_ptr<FunctionInfoIndex> Index; |
| if (!FunctionIndex.empty()) { |
| ErrorOr<std::unique_ptr<FunctionInfoIndex>> IndexOrErr = |
| llvm::getFunctionIndexForFile(FunctionIndex, diagnosticHandler); |
| std::error_code EC = IndexOrErr.getError(); |
| if (EC) { |
| errs() << EC.message() << '\n'; |
| return false; |
| } |
| Index = std::move(IndexOrErr.get()); |
| } |
| |
| // Save the mapping of value ids to temporary metadata created when |
| // importing this function. If we have already imported from this module, |
| // add new temporary metadata to the existing mapping. |
| auto &TempMDVals = ModuleToTempMDValsMap[FileName]; |
| if (!TempMDVals) |
| TempMDVals = llvm::make_unique<DenseMap<unsigned, MDNode *>>(); |
| |
| // Link in the specified function. |
| DenseSet<const GlobalValue *> FunctionsToImport; |
| FunctionsToImport.insert(F); |
| if (L.linkInModule(std::move(M), Linker::Flags::None, Index.get(), |
| &FunctionsToImport, TempMDVals.get())) |
| return false; |
| } |
| |
| // Now link in metadata for all modules from which we imported functions. |
| for (StringMapEntry<std::unique_ptr<DenseMap<unsigned, MDNode *>>> &SME : |
| ModuleToTempMDValsMap) { |
| // Load the specified source module. |
| std::unique_ptr<Module> M = loadFile(argv0, SME.getKey(), Context, true); |
| if (!M.get()) { |
| errs() << argv0 << ": error loading file '" << SME.getKey() << "'\n"; |
| return false; |
| } |
| |
| if (verifyModule(*M, &errs())) { |
| errs() << argv0 << ": " << SME.getKey() |
| << ": error: input module is broken!\n"; |
| return false; |
| } |
| |
| // Link in all necessary metadata from this module. |
| if (L.linkInMetadata(*M, SME.getValue().get())) |
| return false; |
| } |
| 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; |
| for (const auto &File : Files) { |
| std::unique_ptr<Module> M = loadFile(argv0, File, Context); |
| if (!M.get()) { |
| errs() << argv0 << ": error loading file '" << File << "'\n"; |
| return false; |
| } |
| |
| if (verifyModule(*M, &errs())) { |
| errs() << argv0 << ": " << File << ": error: input module is broken!\n"; |
| return false; |
| } |
| |
| // If a function index is supplied, load it so linkInModule can treat |
| // local functions/variables as exported and promote if necessary. |
| std::unique_ptr<FunctionInfoIndex> Index; |
| if (!FunctionIndex.empty()) { |
| ErrorOr<std::unique_ptr<FunctionInfoIndex>> IndexOrErr = |
| llvm::getFunctionIndexForFile(FunctionIndex, diagnosticHandler); |
| std::error_code EC = IndexOrErr.getError(); |
| if (EC) { |
| errs() << EC.message() << '\n'; |
| return false; |
| } |
| Index = std::move(IndexOrErr.get()); |
| } |
| |
| if (Verbose) |
| errs() << "Linking in '" << File << "'\n"; |
| |
| if (L.linkInModule(std::move(M), ApplicableFlags, Index.get())) |
| return false; |
| // All linker flags apply to linking of subsequent files. |
| ApplicableFlags = Flags; |
| |
| // If requested for testing, preserve modules by releasing them from |
| // the unique_ptr before the are freed. This can help catch any |
| // cross-module references from e.g. unneeded metadata references |
| // that aren't properly set to null but instead mapped to the source |
| // module version. The bitcode writer will assert if it finds any such |
| // cross-module references. |
| if (PreserveModules) |
| M.release(); |
| } |
| |
| return true; |
| } |
| |
| int main(int argc, char **argv) { |
| // Print a stack trace if we signal out. |
| sys::PrintStackTraceOnErrorSignal(); |
| PrettyStackTraceProgram X(argc, argv); |
| |
| LLVMContext &Context = getGlobalContext(); |
| Context.setDiagnosticHandler(diagnosticHandlerWithContext, nullptr, true); |
| |
| llvm_shutdown_obj Y; // Call llvm_shutdown() on exit. |
| cl::ParseCommandLineOptions(argc, argv, "llvm linker\n"); |
| |
| auto Composite = make_unique<Module>("llvm-link", Context); |
| Linker L(*Composite); |
| |
| unsigned Flags = Linker::Flags::None; |
| if (Internalize) |
| Flags |= Linker::Flags::InternalizeLinkedSymbols; |
| 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], Context, L)) |
| return 1; |
| |
| if (DumpAsm) errs() << "Here's the assembly:\n" << *Composite; |
| |
| std::error_code EC; |
| tool_output_file Out(OutputFilename, EC, sys::fs::F_None); |
| if (EC) { |
| errs() << EC.message() << '\n'; |
| return 1; |
| } |
| |
| if (verifyModule(*Composite, &errs())) { |
| errs() << argv[0] << ": 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.get(), Out.os(), PreserveBitcodeUseListOrder); |
| |
| // Declare success. |
| Out.keep(); |
| |
| return 0; |
| } |