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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/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<bool>
DisableOpt("disable-opt", cl::init(false),
cl::desc("Do not run any optimization passes"));
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::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);
namespace {
struct ModuleInfo {
std::vector<bool> CanBeHidden;
};
}
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");
// Initialize the configured targets.
InitializeAllTargets();
InitializeAllTargetMCs();
InitializeAllAsmPrinters();
InitializeAllAsmParsers();
// set up the TargetOptions for the machine
TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
unsigned BaseArg = 0;
LTOCodeGenerator CodeGen;
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;
}
if (!CodeGen.addModule(Module.get(), error)) {
errs() << argv[0] << ": error adding file '" << InputFilenames[i]
<< "': " << error << "\n";
return 1;
}
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);
}
}
// 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());
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, DisableOpt, DisableInline,
DisableGVNLoadPRE, ErrorInfo);
if (!Code) {
errs() << argv[0]
<< ": error compiling the code: " << ErrorInfo << "\n";
return 1;
}
raw_fd_ostream FileStream(OutputFilename.c_str(), ErrorInfo,
sys::fs::F_None);
if (!ErrorInfo.empty()) {
errs() << argv[0] << ": error opening the file '" << OutputFilename
<< "': " << ErrorInfo << "\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, DisableOpt, DisableInline,
DisableGVNLoadPRE, ErrorInfo)) {
errs() << argv[0]
<< ": error compiling the code: " << ErrorInfo
<< "\n";
return 1;
}
outs() << "Wrote native object file '" << OutputName << "'\n";
}
return 0;
}
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