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+//===-- llvm-lto: a simple command-line program to link modules with LTO --===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This program takes in a list of bitcode files, links them, performs link-time
+// optimization, and outputs an object file.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/StringSet.h"
+#include "llvm/Bitcode/ReaderWriter.h"
+#include "llvm/CodeGen/CommandFlags.h"
+#include "llvm/IR/DiagnosticPrinter.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/LTO/LTOCodeGenerator.h"
+#include "llvm/LTO/LTOModule.h"
+#include "llvm/Object/FunctionIndexObjectFile.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/ToolOutputFile.h"
+#include "llvm/Support/raw_ostream.h"
+#include <list>
+
+using namespace llvm;
+
+static cl::opt<char>
+OptLevel("O",
+ cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
+ "(default = '-O2')"),
+ cl::Prefix,
+ cl::ZeroOrMore,
+ cl::init('2'));
+
+static cl::opt<bool> DisableVerify(
+ "disable-verify", cl::init(false),
+ cl::desc("Do not run the verifier during the optimization pipeline"));
+
+static cl::opt<bool>
+DisableInline("disable-inlining", cl::init(false),
+ cl::desc("Do not run the inliner pass"));
+
+static cl::opt<bool>
+DisableGVNLoadPRE("disable-gvn-loadpre", cl::init(false),
+ cl::desc("Do not run the GVN load PRE pass"));
+
+static cl::opt<bool>
+DisableLTOVectorization("disable-lto-vectorization", cl::init(false),
+ cl::desc("Do not run loop or slp vectorization during LTO"));
+
+static cl::opt<bool>
+UseDiagnosticHandler("use-diagnostic-handler", cl::init(false),
+ cl::desc("Use a diagnostic handler to test the handler interface"));
+
+static cl::opt<bool>
+ ThinLTO("thinlto", cl::init(false),
+ cl::desc("Only write combined global index for ThinLTO backends"));
+
+static cl::opt<bool>
+SaveModuleFile("save-merged-module", cl::init(false),
+ cl::desc("Write merged LTO module to file before CodeGen"));
+
+static cl::list<std::string>
+InputFilenames(cl::Positional, cl::OneOrMore,
+ cl::desc("<input bitcode files>"));
+
+static cl::opt<std::string>
+OutputFilename("o", cl::init(""),
+ cl::desc("Override output filename"),
+ cl::value_desc("filename"));
+
+static cl::list<std::string>
+ExportedSymbols("exported-symbol",
+ cl::desc("Symbol to export from the resulting object file"),
+ cl::ZeroOrMore);
+
+static cl::list<std::string>
+DSOSymbols("dso-symbol",
+ cl::desc("Symbol to put in the symtab in the resulting dso"),
+ cl::ZeroOrMore);
+
+static cl::opt<bool> ListSymbolsOnly(
+ "list-symbols-only", cl::init(false),
+ cl::desc("Instead of running LTO, list the symbols in each IR file"));
+
+static cl::opt<bool> SetMergedModule(
+ "set-merged-module", cl::init(false),
+ cl::desc("Use the first input module as the merged module"));
+
+static cl::opt<unsigned> Parallelism("j", cl::Prefix, cl::init(1),
+ cl::desc("Number of backend threads"));
+
+namespace {
+struct ModuleInfo {
+ std::vector<bool> CanBeHidden;
+};
+}
+
+static void handleDiagnostics(lto_codegen_diagnostic_severity_t Severity,
+ const char *Msg, void *) {
+ errs() << "llvm-lto: ";
+ switch (Severity) {
+ case LTO_DS_NOTE:
+ errs() << "note: ";
+ break;
+ case LTO_DS_REMARK:
+ errs() << "remark: ";
+ break;
+ case LTO_DS_ERROR:
+ errs() << "error: ";
+ break;
+ case LTO_DS_WARNING:
+ errs() << "warning: ";
+ break;
+ }
+ errs() << Msg << "\n";
+}
+
+static std::string CurrentActivity;
+static void diagnosticHandler(const DiagnosticInfo &DI) {
+ raw_ostream &OS = errs();
+ OS << "llvm-lto: ";
+ switch (DI.getSeverity()) {
+ case DS_Error:
+ OS << "error";
+ break;
+ case DS_Warning:
+ OS << "warning";
+ break;
+ case DS_Remark:
+ OS << "remark";
+ break;
+ case DS_Note:
+ OS << "note";
+ break;
+ }
+ if (!CurrentActivity.empty())
+ OS << ' ' << CurrentActivity;
+ OS << ": ";
+
+ DiagnosticPrinterRawOStream DP(OS);
+ DI.print(DP);
+ OS << '\n';
+
+ if (DI.getSeverity() == DS_Error)
+ exit(1);
+}
+
+static void diagnosticHandlerWithContenxt(const DiagnosticInfo &DI,
+ void *Context) {
+ diagnosticHandler(DI);
+}
+
+static void error(const Twine &Msg) {
+ errs() << "llvm-lto: " << Msg << '\n';
+ exit(1);
+}
+
+static void error(std::error_code EC, const Twine &Prefix) {
+ if (EC)
+ error(Prefix + ": " + EC.message());
+}
+
+template <typename T>
+static void error(const ErrorOr<T> &V, const Twine &Prefix) {
+ error(V.getError(), Prefix);
+}
+
+static std::unique_ptr<LTOModule>
+getLocalLTOModule(StringRef Path, std::unique_ptr<MemoryBuffer> &Buffer,
+ const TargetOptions &Options) {
+ ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
+ MemoryBuffer::getFile(Path);
+ error(BufferOrErr, "error loading file '" + Path + "'");
+ Buffer = std::move(BufferOrErr.get());
+ CurrentActivity = ("loading file '" + Path + "'").str();
+ ErrorOr<std::unique_ptr<LTOModule>> Ret = LTOModule::createInLocalContext(
+ Buffer->getBufferStart(), Buffer->getBufferSize(), Options, Path);
+ CurrentActivity = "";
+ return std::move(*Ret);
+}
+
+/// \brief List symbols in each IR file.
+///
+/// The main point here is to provide lit-testable coverage for the LTOModule
+/// functionality that's exposed by the C API to list symbols. Moreover, this
+/// provides testing coverage for modules that have been created in their own
+/// contexts.
+static void listSymbols(const TargetOptions &Options) {
+ for (auto &Filename : InputFilenames) {
+ std::unique_ptr<MemoryBuffer> Buffer;
+ std::unique_ptr<LTOModule> Module =
+ getLocalLTOModule(Filename, Buffer, Options);
+
+ // List the symbols.
+ outs() << Filename << ":\n";
+ for (int I = 0, E = Module->getSymbolCount(); I != E; ++I)
+ outs() << Module->getSymbolName(I) << "\n";
+ }
+}
+
+/// Create a combined index file from the input IR files and write it.
+///
+/// This is meant to enable testing of ThinLTO combined index generation,
+/// currently available via the gold plugin via -thinlto.
+static void createCombinedFunctionIndex() {
+ FunctionInfoIndex CombinedIndex;
+ uint64_t NextModuleId = 0;
+ for (auto &Filename : InputFilenames) {
+ CurrentActivity = "loading file '" + Filename + "'";
+ ErrorOr<std::unique_ptr<FunctionInfoIndex>> IndexOrErr =
+ llvm::getFunctionIndexForFile(Filename, diagnosticHandler);
+ std::unique_ptr<FunctionInfoIndex> Index = std::move(IndexOrErr.get());
+ CurrentActivity = "";
+ // Skip files without a function summary.
+ if (!Index)
+ continue;
+ CombinedIndex.mergeFrom(std::move(Index), ++NextModuleId);
+ }
+ std::error_code EC;
+ assert(!OutputFilename.empty());
+ raw_fd_ostream OS(OutputFilename + ".thinlto.bc", EC,
+ sys::fs::OpenFlags::F_None);
+ error(EC, "error opening the file '" + OutputFilename + ".thinlto.bc'");
+ WriteFunctionSummaryToFile(CombinedIndex, OS);
+ OS.close();
+}
+
+int main(int argc, char **argv) {
+ // Print a stack trace if we signal out.
+ sys::PrintStackTraceOnErrorSignal();
+ PrettyStackTraceProgram X(argc, argv);
+
+ llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
+ cl::ParseCommandLineOptions(argc, argv, "llvm LTO linker\n");
+
+ if (OptLevel < '0' || OptLevel > '3')
+ error("optimization level must be between 0 and 3");
+
+ // Initialize the configured targets.
+ InitializeAllTargets();
+ InitializeAllTargetMCs();
+ InitializeAllAsmPrinters();
+ InitializeAllAsmParsers();
+
+ // set up the TargetOptions for the machine
+ TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
+
+ if (ListSymbolsOnly) {
+ listSymbols(Options);
+ return 0;
+ }
+
+ if (ThinLTO) {
+ createCombinedFunctionIndex();
+ return 0;
+ }
+
+ unsigned BaseArg = 0;
+
+ LLVMContext Context;
+ Context.setDiagnosticHandler(diagnosticHandlerWithContenxt, nullptr, true);
+
+ LTOCodeGenerator CodeGen(Context);
+
+ if (UseDiagnosticHandler)
+ CodeGen.setDiagnosticHandler(handleDiagnostics, nullptr);
+
+ CodeGen.setCodePICModel(RelocModel);
+
+ CodeGen.setDebugInfo(LTO_DEBUG_MODEL_DWARF);
+ CodeGen.setTargetOptions(Options);
+
+ llvm::StringSet<llvm::MallocAllocator> DSOSymbolsSet;
+ for (unsigned i = 0; i < DSOSymbols.size(); ++i)
+ DSOSymbolsSet.insert(DSOSymbols[i]);
+
+ std::vector<std::string> KeptDSOSyms;
+
+ for (unsigned i = BaseArg; i < InputFilenames.size(); ++i) {
+ CurrentActivity = "loading file '" + InputFilenames[i] + "'";
+ ErrorOr<std::unique_ptr<LTOModule>> ModuleOrErr =
+ LTOModule::createFromFile(Context, InputFilenames[i].c_str(), Options);
+ std::unique_ptr<LTOModule> &Module = *ModuleOrErr;
+ CurrentActivity = "";
+
+ unsigned NumSyms = Module->getSymbolCount();
+ for (unsigned I = 0; I < NumSyms; ++I) {
+ StringRef Name = Module->getSymbolName(I);
+ if (!DSOSymbolsSet.count(Name))
+ continue;
+ lto_symbol_attributes Attrs = Module->getSymbolAttributes(I);
+ unsigned Scope = Attrs & LTO_SYMBOL_SCOPE_MASK;
+ if (Scope != LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN)
+ KeptDSOSyms.push_back(Name);
+ }
+
+ // We use the first input module as the destination module when
+ // SetMergedModule is true.
+ if (SetMergedModule && i == BaseArg) {
+ // Transfer ownership to the code generator.
+ CodeGen.setModule(std::move(Module));
+ } else if (!CodeGen.addModule(Module.get())) {
+ // Print a message here so that we know addModule() did not abort.
+ errs() << argv[0] << ": error adding file '" << InputFilenames[i] << "'\n";
+ return 1;
+ }
+ }
+
+ // Add all the exported symbols to the table of symbols to preserve.
+ for (unsigned i = 0; i < ExportedSymbols.size(); ++i)
+ CodeGen.addMustPreserveSymbol(ExportedSymbols[i].c_str());
+
+ // Add all the dso symbols to the table of symbols to expose.
+ for (unsigned i = 0; i < KeptDSOSyms.size(); ++i)
+ CodeGen.addMustPreserveSymbol(KeptDSOSyms[i].c_str());
+
+ // Set cpu and attrs strings for the default target/subtarget.
+ CodeGen.setCpu(MCPU.c_str());
+
+ CodeGen.setOptLevel(OptLevel - '0');
+
+ std::string attrs;
+ for (unsigned i = 0; i < MAttrs.size(); ++i) {
+ if (i > 0)
+ attrs.append(",");
+ attrs.append(MAttrs[i]);
+ }
+
+ if (!attrs.empty())
+ CodeGen.setAttr(attrs.c_str());
+
+ if (FileType.getNumOccurrences())
+ CodeGen.setFileType(FileType);
+
+ if (!OutputFilename.empty()) {
+ if (!CodeGen.optimize(DisableVerify, DisableInline, DisableGVNLoadPRE,
+ DisableLTOVectorization)) {
+ // Diagnostic messages should have been printed by the handler.
+ errs() << argv[0] << ": error optimizing the code\n";
+ return 1;
+ }
+
+ if (SaveModuleFile) {
+ std::string ModuleFilename = OutputFilename;
+ ModuleFilename += ".merged.bc";
+ std::string ErrMsg;
+
+ if (!CodeGen.writeMergedModules(ModuleFilename.c_str())) {
+ errs() << argv[0] << ": writing merged module failed.\n";
+ return 1;
+ }
+ }
+
+ std::list<tool_output_file> OSs;
+ std::vector<raw_pwrite_stream *> OSPtrs;
+ for (unsigned I = 0; I != Parallelism; ++I) {
+ std::string PartFilename = OutputFilename;
+ if (Parallelism != 1)
+ PartFilename += "." + utostr(I);
+ std::error_code EC;
+ OSs.emplace_back(PartFilename, EC, sys::fs::F_None);
+ if (EC) {
+ errs() << argv[0] << ": error opening the file '" << PartFilename
+ << "': " << EC.message() << "\n";
+ return 1;
+ }
+ OSPtrs.push_back(&OSs.back().os());
+ }
+
+ if (!CodeGen.compileOptimized(OSPtrs)) {
+ // Diagnostic messages should have been printed by the handler.
+ errs() << argv[0] << ": error compiling the code\n";
+ return 1;
+ }
+
+ for (tool_output_file &OS : OSs)
+ OS.keep();
+ } else {
+ if (Parallelism != 1) {
+ errs() << argv[0] << ": -j must be specified together with -o\n";
+ return 1;
+ }
+
+ if (SaveModuleFile) {
+ errs() << argv[0] << ": -save-merged-module must be specified with -o\n";
+ return 1;
+ }
+
+ const char *OutputName = nullptr;
+ if (!CodeGen.compile_to_file(&OutputName, DisableVerify, DisableInline,
+ DisableGVNLoadPRE, DisableLTOVectorization)) {
+ // Diagnostic messages should have been printed by the handler.
+ errs() << argv[0] << ": error compiling the code\n";
+ return 1;
+ }
+
+ outs() << "Wrote native object file '" << OutputName << "'\n";
+ }
+
+ return 0;
+}
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