llvm-project/llvm/tools/llvm-lto/llvm-lto.cpp

412 lines
13 KiB
C++

//===-- 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);
error(ModuleOrErr, "error " + CurrentActivity);
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;
}