Imported Upstream version 5.18.0.179

Former-commit-id: 67aa10e65b237e1c4537630979ee99ebe1374215

external/llvm/tools/llvm-link/llvm-link.cpp

@@ -0,0 +1,407 @@
+//===- 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/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/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 "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:
+      errs() << "ERROR: ";
+      break;
+    case DS_Warning:
+      if (SuppressWarnings)
+        return true;
+      errs() << "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
+             << ": 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(std::make_pair(F->getGUID(), /* (Unused) threshold */ 1.0));
+  }
+  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 << ": 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 << ": 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) {
+  // Print a stack trace if we signal out.
+  sys::PrintStackTraceOnErrorSignal(argv[0]);
+  PrettyStackTraceProgram X(argc, argv);
+
+  ExitOnErr.setBanner(std::string(argv[0]) + ": ");
+
+  LLVMContext Context;
+  Context.setDiagnosticHandler(
+    llvm::make_unique<LLVMLinkDiagnosticHandler>(), true);
+  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
+  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) {
+    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;
+}