llvm-6502/tools/llvm-lto/llvm-lto.cpp
Peter Collingbourne 416d8ecf80 libLTO, llvm-lto, gold: Introduce flag for controlling optimization level.
This change also introduces a link-time optimization level of 1. This
optimization level runs only the globaldce pass as well as cleanup passes for
passes that run at -O0, specifically simplifycfg which cleans up lowerbitsets.

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150316/266951.html

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232769 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-19 22:01:00 +00:00

293 lines
8.9 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/CodeGen/CommandFlags.h"
#include "llvm/LTO/LTOCodeGenerator.h"
#include "llvm/LTO/LTOModule.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/raw_ostream.h"
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>
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::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"));
namespace {
struct ModuleInfo {
std::vector<bool> CanBeHidden;
};
}
static void handleDiagnostics(lto_codegen_diagnostic_severity_t Severity,
const char *Msg, void *) {
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::unique_ptr<LTOModule>
getLocalLTOModule(StringRef Path, std::unique_ptr<MemoryBuffer> &Buffer,
const TargetOptions &Options, std::string &Error) {
ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
MemoryBuffer::getFile(Path);
if (std::error_code EC = BufferOrErr.getError()) {
Error = EC.message();
return nullptr;
}
Buffer = std::move(BufferOrErr.get());
return std::unique_ptr<LTOModule>(LTOModule::createInLocalContext(
Buffer->getBufferStart(), Buffer->getBufferSize(), Options, Error, Path));
}
/// \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 int listSymbols(StringRef Command, const TargetOptions &Options) {
for (auto &Filename : InputFilenames) {
std::string Error;
std::unique_ptr<MemoryBuffer> Buffer;
std::unique_ptr<LTOModule> Module =
getLocalLTOModule(Filename, Buffer, Options, Error);
if (!Module) {
errs() << Command << ": error loading file '" << Filename
<< "': " << Error << "\n";
return 1;
}
// List the symbols.
outs() << Filename << ":\n";
for (int I = 0, E = Module->getSymbolCount(); I != E; ++I)
outs() << Module->getSymbolName(I) << "\n";
}
return 0;
}
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') {
errs() << argv[0] << ": optimization level must be between 0 and 3\n";
return 1;
}
// Initialize the configured targets.
InitializeAllTargets();
InitializeAllTargetMCs();
InitializeAllAsmPrinters();
InitializeAllAsmParsers();
// set up the TargetOptions for the machine
TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
if (ListSymbolsOnly)
return listSymbols(argv[0], Options);
unsigned BaseArg = 0;
LTOCodeGenerator CodeGen;
if (UseDiagnosticHandler)
CodeGen.setDiagnosticHandler(handleDiagnostics, nullptr);
switch (RelocModel) {
case Reloc::Static:
CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_STATIC);
break;
case Reloc::PIC_:
CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC);
break;
case Reloc::DynamicNoPIC:
CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC);
break;
default:
CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DEFAULT);
}
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) {
std::string error;
std::unique_ptr<LTOModule> Module(
LTOModule::createFromFile(InputFilenames[i].c_str(), Options, error));
if (!error.empty()) {
errs() << argv[0] << ": error loading file '" << InputFilenames[i]
<< "': " << error << "\n";
return 1;
}
LTOModule *LTOMod = Module.get();
// 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(Module.release());
} else if (!CodeGen.addModule(Module.get()))
return 1;
unsigned NumSyms = LTOMod->getSymbolCount();
for (unsigned I = 0; I < NumSyms; ++I) {
StringRef Name = LTOMod->getSymbolName(I);
if (!DSOSymbolsSet.count(Name))
continue;
lto_symbol_attributes Attrs = LTOMod->getSymbolAttributes(I);
unsigned Scope = Attrs & LTO_SYMBOL_SCOPE_MASK;
if (Scope != LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN)
KeptDSOSyms.push_back(Name);
}
}
// 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 (!OutputFilename.empty()) {
size_t len = 0;
std::string ErrorInfo;
const void *Code =
CodeGen.compile(&len, DisableInline, DisableGVNLoadPRE,
DisableLTOVectorization, ErrorInfo);
if (!Code) {
errs() << argv[0]
<< ": error compiling the code: " << ErrorInfo << "\n";
return 1;
}
std::error_code EC;
raw_fd_ostream FileStream(OutputFilename, EC, sys::fs::F_None);
if (EC) {
errs() << argv[0] << ": error opening the file '" << OutputFilename
<< "': " << EC.message() << "\n";
return 1;
}
FileStream.write(reinterpret_cast<const char *>(Code), len);
} else {
std::string ErrorInfo;
const char *OutputName = nullptr;
if (!CodeGen.compile_to_file(&OutputName, DisableInline,
DisableGVNLoadPRE, DisableLTOVectorization,
ErrorInfo)) {
errs() << argv[0]
<< ": error compiling the code: " << ErrorInfo
<< "\n";
return 1;
}
outs() << "Wrote native object file '" << OutputName << "'\n";
}
return 0;
}