400 lines
13 KiB
C++
400 lines
13 KiB
C++
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//===- llvm-link.cpp - Low-level LLVM linker ------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This utility may be invoked in the following manner:
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// llvm-link a.bc b.bc c.bc -o x.bc
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Bitcode/ReaderWriter.h"
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#include "llvm/IR/AutoUpgrade.h"
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#include "llvm/IR/DiagnosticInfo.h"
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#include "llvm/IR/DiagnosticPrinter.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/ModuleSummaryIndex.h"
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#include "llvm/IR/Verifier.h"
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#include "llvm/IRReader/IRReader.h"
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#include "llvm/Linker/Linker.h"
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#include "llvm/Object/ModuleSummaryIndexObjectFile.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/FileSystem.h"
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#include "llvm/Support/ManagedStatic.h"
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#include "llvm/Support/Path.h"
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#include "llvm/Support/PrettyStackTrace.h"
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#include "llvm/Support/Signals.h"
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#include "llvm/Support/SourceMgr.h"
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#include "llvm/Support/SystemUtils.h"
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#include "llvm/Support/ToolOutputFile.h"
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#include "llvm/Transforms/Utils/FunctionImportUtils.h"
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#include <memory>
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#include <utility>
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using namespace llvm;
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static cl::list<std::string>
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InputFilenames(cl::Positional, cl::OneOrMore,
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cl::desc("<input bitcode files>"));
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static cl::list<std::string> OverridingInputs(
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"override", cl::ZeroOrMore, cl::value_desc("filename"),
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cl::desc(
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"input bitcode file which can override previously defined symbol(s)"));
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// Option to simulate function importing for testing. This enables using
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// llvm-link to simulate ThinLTO backend processes.
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static cl::list<std::string> Imports(
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"import", cl::ZeroOrMore, cl::value_desc("function:filename"),
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cl::desc("Pair of function name and filename, where function should be "
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"imported from bitcode in filename"));
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// Option to support testing of function importing. The module summary
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// must be specified in the case were we request imports via the -import
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// option, as well as when compiling any module with functions that may be
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// exported (imported by a different llvm-link -import invocation), to ensure
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// consistent promotion and renaming of locals.
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static cl::opt<std::string>
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SummaryIndex("summary-index", cl::desc("Module summary index filename"),
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cl::init(""), cl::value_desc("filename"));
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static cl::opt<std::string>
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OutputFilename("o", cl::desc("Override output filename"), cl::init("-"),
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cl::value_desc("filename"));
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static cl::opt<bool>
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Internalize("internalize", cl::desc("Internalize linked symbols"));
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static cl::opt<bool>
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DisableDITypeMap("disable-debug-info-type-map",
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cl::desc("Don't use a uniquing type map for debug info"));
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static cl::opt<bool>
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OnlyNeeded("only-needed", cl::desc("Link only needed symbols"));
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static cl::opt<bool>
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Force("f", cl::desc("Enable binary output on terminals"));
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static cl::opt<bool>
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OutputAssembly("S",
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cl::desc("Write output as LLVM assembly"), cl::Hidden);
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static cl::opt<bool>
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Verbose("v", cl::desc("Print information about actions taken"));
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static cl::opt<bool>
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DumpAsm("d", cl::desc("Print assembly as linked"), cl::Hidden);
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static cl::opt<bool>
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SuppressWarnings("suppress-warnings", cl::desc("Suppress all linking warnings"),
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cl::init(false));
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static cl::opt<bool> PreserveBitcodeUseListOrder(
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"preserve-bc-uselistorder",
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cl::desc("Preserve use-list order when writing LLVM bitcode."),
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cl::init(true), cl::Hidden);
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static cl::opt<bool> PreserveAssemblyUseListOrder(
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"preserve-ll-uselistorder",
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cl::desc("Preserve use-list order when writing LLVM assembly."),
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cl::init(false), cl::Hidden);
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// Read the specified bitcode file in and return it. This routine searches the
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// link path for the specified file to try to find it...
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//
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static std::unique_ptr<Module> loadFile(const char *argv0,
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const std::string &FN,
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LLVMContext &Context,
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bool MaterializeMetadata = true) {
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SMDiagnostic Err;
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if (Verbose) errs() << "Loading '" << FN << "'\n";
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std::unique_ptr<Module> Result =
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getLazyIRFileModule(FN, Err, Context, !MaterializeMetadata);
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if (!Result) {
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Err.print(argv0, errs());
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return nullptr;
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}
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if (MaterializeMetadata) {
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Result->materializeMetadata();
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UpgradeDebugInfo(*Result);
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}
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return Result;
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}
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namespace {
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/// Helper to load on demand a Module from file and cache it for subsequent
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/// queries during function importing.
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class ModuleLazyLoaderCache {
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/// Cache of lazily loaded module for import.
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StringMap<std::unique_ptr<Module>> ModuleMap;
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/// Retrieve a Module from the cache or lazily load it on demand.
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std::function<std::unique_ptr<Module>(const char *argv0,
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const std::string &FileName)>
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createLazyModule;
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public:
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/// Create the loader, Module will be initialized in \p Context.
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ModuleLazyLoaderCache(std::function<std::unique_ptr<Module>(
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const char *argv0, const std::string &FileName)>
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createLazyModule)
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: createLazyModule(std::move(createLazyModule)) {}
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/// Retrieve a Module from the cache or lazily load it on demand.
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Module &operator()(const char *argv0, const std::string &FileName);
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std::unique_ptr<Module> takeModule(const std::string &FileName) {
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auto I = ModuleMap.find(FileName);
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assert(I != ModuleMap.end());
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std::unique_ptr<Module> Ret = std::move(I->second);
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ModuleMap.erase(I);
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return Ret;
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}
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};
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// Get a Module for \p FileName from the cache, or load it lazily.
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Module &ModuleLazyLoaderCache::operator()(const char *argv0,
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const std::string &Identifier) {
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auto &Module = ModuleMap[Identifier];
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if (!Module)
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Module = createLazyModule(argv0, Identifier);
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return *Module;
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}
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} // anonymous namespace
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static void diagnosticHandler(const DiagnosticInfo &DI) {
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unsigned Severity = DI.getSeverity();
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switch (Severity) {
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case DS_Error:
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errs() << "ERROR: ";
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break;
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case DS_Warning:
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if (SuppressWarnings)
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return;
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errs() << "WARNING: ";
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break;
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case DS_Remark:
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case DS_Note:
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llvm_unreachable("Only expecting warnings and errors");
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}
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DiagnosticPrinterRawOStream DP(errs());
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DI.print(DP);
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errs() << '\n';
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}
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static void diagnosticHandlerWithContext(const DiagnosticInfo &DI, void *C) {
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diagnosticHandler(DI);
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}
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/// Import any functions requested via the -import option.
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static bool importFunctions(const char *argv0, LLVMContext &Context,
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Linker &L) {
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if (SummaryIndex.empty())
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return true;
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ErrorOr<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
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llvm::getModuleSummaryIndexForFile(SummaryIndex, diagnosticHandler);
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std::error_code EC = IndexOrErr.getError();
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if (EC) {
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errs() << EC.message() << '\n';
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return false;
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}
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auto Index = std::move(IndexOrErr.get());
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// Map of Module -> List of globals to import from the Module
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std::map<StringRef, DenseSet<const GlobalValue *>> ModuleToGlobalsToImportMap;
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auto ModuleLoader = [&Context](const char *argv0,
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const std::string &Identifier) {
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return loadFile(argv0, Identifier, Context, false);
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};
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ModuleLazyLoaderCache ModuleLoaderCache(ModuleLoader);
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for (const auto &Import : Imports) {
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// Identify the requested function and its bitcode source file.
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size_t Idx = Import.find(':');
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if (Idx == std::string::npos) {
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errs() << "Import parameter bad format: " << Import << "\n";
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return false;
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}
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std::string FunctionName = Import.substr(0, Idx);
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std::string FileName = Import.substr(Idx + 1, std::string::npos);
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// Load the specified source module.
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auto &SrcModule = ModuleLoaderCache(argv0, FileName);
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if (verifyModule(SrcModule, &errs())) {
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errs() << argv0 << ": " << FileName
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<< ": error: input module is broken!\n";
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return false;
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}
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Function *F = SrcModule.getFunction(FunctionName);
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if (!F) {
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errs() << "Ignoring import request for non-existent function "
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<< FunctionName << " from " << FileName << "\n";
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continue;
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}
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// We cannot import weak_any functions without possibly affecting the
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// order they are seen and selected by the linker, changing program
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// semantics.
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if (F->hasWeakAnyLinkage()) {
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errs() << "Ignoring import request for weak-any function " << FunctionName
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<< " from " << FileName << "\n";
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continue;
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}
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if (Verbose)
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errs() << "Importing " << FunctionName << " from " << FileName << "\n";
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auto &Entry = ModuleToGlobalsToImportMap[SrcModule.getModuleIdentifier()];
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Entry.insert(F);
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F->materialize();
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}
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// Do the actual import of globals now, one Module at a time
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for (auto &GlobalsToImportPerModule : ModuleToGlobalsToImportMap) {
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// Get the module for the import
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auto &GlobalsToImport = GlobalsToImportPerModule.second;
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std::unique_ptr<Module> SrcModule =
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ModuleLoaderCache.takeModule(GlobalsToImportPerModule.first);
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assert(&Context == &SrcModule->getContext() && "Context mismatch");
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// If modules were created with lazy metadata loading, materialize it
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// now, before linking it (otherwise this will be a noop).
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SrcModule->materializeMetadata();
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UpgradeDebugInfo(*SrcModule);
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// Linkage Promotion and renaming
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if (renameModuleForThinLTO(*SrcModule, *Index, &GlobalsToImport))
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return true;
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// Instruct the linker to not automatically import linkonce defintion.
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unsigned Flags = Linker::Flags::DontForceLinkLinkonceODR;
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if (L.linkInModule(std::move(SrcModule), Flags, &GlobalsToImport))
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return false;
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}
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return true;
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}
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static bool linkFiles(const char *argv0, LLVMContext &Context, Linker &L,
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const cl::list<std::string> &Files,
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unsigned Flags) {
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// Filter out flags that don't apply to the first file we load.
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unsigned ApplicableFlags = Flags & Linker::Flags::OverrideFromSrc;
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for (const auto &File : Files) {
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std::unique_ptr<Module> M = loadFile(argv0, File, Context);
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if (!M.get()) {
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errs() << argv0 << ": error loading file '" << File << "'\n";
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return false;
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}
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// Note that when ODR merging types cannot verify input files in here When
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// doing that debug metadata in the src module might already be pointing to
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// the destination.
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if (DisableDITypeMap && verifyModule(*M, &errs())) {
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errs() << argv0 << ": " << File << ": error: input module is broken!\n";
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return false;
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}
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// If a module summary index is supplied, load it so linkInModule can treat
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// local functions/variables as exported and promote if necessary.
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if (!SummaryIndex.empty()) {
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ErrorOr<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
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llvm::getModuleSummaryIndexForFile(SummaryIndex, diagnosticHandler);
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std::error_code EC = IndexOrErr.getError();
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if (EC) {
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errs() << EC.message() << '\n';
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return false;
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}
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auto Index = std::move(IndexOrErr.get());
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// Promotion
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if (renameModuleForThinLTO(*M, *Index))
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return true;
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}
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if (Verbose)
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errs() << "Linking in '" << File << "'\n";
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if (L.linkInModule(std::move(M), ApplicableFlags))
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return false;
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// All linker flags apply to linking of subsequent files.
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ApplicableFlags = Flags;
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}
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return true;
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}
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int main(int argc, char **argv) {
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// Print a stack trace if we signal out.
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sys::PrintStackTraceOnErrorSignal(argv[0]);
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PrettyStackTraceProgram X(argc, argv);
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LLVMContext Context;
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Context.setDiagnosticHandler(diagnosticHandlerWithContext, nullptr, true);
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llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
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cl::ParseCommandLineOptions(argc, argv, "llvm linker\n");
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if (!DisableDITypeMap)
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Context.enableDebugTypeODRUniquing();
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auto Composite = make_unique<Module>("llvm-link", Context);
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Linker L(*Composite);
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unsigned Flags = Linker::Flags::None;
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if (Internalize)
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Flags |= Linker::Flags::InternalizeLinkedSymbols;
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if (OnlyNeeded)
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Flags |= Linker::Flags::LinkOnlyNeeded;
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// First add all the regular input files
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if (!linkFiles(argv[0], Context, L, InputFilenames, Flags))
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return 1;
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// Next the -override ones.
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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;
|
||
|
|
}
|