mirror of
https://github.com/c64scene-ar/llvm-6502.git
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988fdc5f28
materialise them in LTO. I observed a ~0.5-1% speedup for an LTO link of opt. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143784 91177308-0d34-0410-b5e6-96231b3b80d8
432 lines
13 KiB
C++
432 lines
13 KiB
C++
//===-LTOCodeGenerator.cpp - LLVM Link Time Optimizer ---------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the Link Time Optimization library. This library is
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// intended to be used by linker to optimize code at link time.
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//
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//===----------------------------------------------------------------------===//
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#include "LTOModule.h"
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#include "LTOCodeGenerator.h"
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Linker.h"
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#include "llvm/LLVMContext.h"
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#include "llvm/Module.h"
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#include "llvm/PassManager.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/ADT/Triple.h"
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#include "llvm/Analysis/Passes.h"
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#include "llvm/Analysis/Verifier.h"
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#include "llvm/Bitcode/ReaderWriter.h"
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#include "llvm/MC/MCAsmInfo.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/SubtargetFeature.h"
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#include "llvm/Target/Mangler.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/FormattedStream.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include "llvm/Support/SystemUtils.h"
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#include "llvm/Support/ToolOutputFile.h"
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#include "llvm/Support/Host.h"
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#include "llvm/Support/Program.h"
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#include "llvm/Support/Signals.h"
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#include "llvm/Support/TargetRegistry.h"
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#include "llvm/Support/TargetSelect.h"
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#include "llvm/Support/system_error.h"
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#include "llvm/Config/config.h"
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#include "llvm/Transforms/IPO.h"
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#include "llvm/Transforms/IPO/PassManagerBuilder.h"
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#include <cstdlib>
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#include <unistd.h>
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#include <fcntl.h>
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using namespace llvm;
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static cl::opt<bool> DisableInline("disable-inlining",
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cl::desc("Do not run the inliner pass"));
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const char* LTOCodeGenerator::getVersionString()
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{
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#ifdef LLVM_VERSION_INFO
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return PACKAGE_NAME " version " PACKAGE_VERSION ", " LLVM_VERSION_INFO;
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#else
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return PACKAGE_NAME " version " PACKAGE_VERSION;
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#endif
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}
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LTOCodeGenerator::LTOCodeGenerator()
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: _context(getGlobalContext()),
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_linker("LinkTimeOptimizer", "ld-temp.o", _context), _target(NULL),
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_emitDwarfDebugInfo(false), _scopeRestrictionsDone(false),
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_codeModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC),
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_nativeObjectFile(NULL)
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{
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InitializeAllTargets();
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InitializeAllTargetMCs();
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InitializeAllAsmPrinters();
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}
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LTOCodeGenerator::~LTOCodeGenerator()
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{
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delete _target;
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delete _nativeObjectFile;
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}
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bool LTOCodeGenerator::addModule(LTOModule* mod, std::string& errMsg)
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{
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bool ret = _linker.LinkInModule(mod->getLLVVMModule(), &errMsg);
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const std::vector<const char*> &undefs = mod->getAsmUndefinedRefs();
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for (int i = 0, e = undefs.size(); i != e; ++i)
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_asmUndefinedRefs[undefs[i]] = 1;
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return ret;
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}
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bool LTOCodeGenerator::setDebugInfo(lto_debug_model debug, std::string& errMsg)
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{
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switch (debug) {
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case LTO_DEBUG_MODEL_NONE:
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_emitDwarfDebugInfo = false;
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return false;
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case LTO_DEBUG_MODEL_DWARF:
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_emitDwarfDebugInfo = true;
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return false;
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}
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errMsg = "unknown debug format";
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return true;
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}
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bool LTOCodeGenerator::setCodePICModel(lto_codegen_model model,
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std::string& errMsg)
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{
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switch (model) {
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case LTO_CODEGEN_PIC_MODEL_STATIC:
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case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
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case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
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_codeModel = model;
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return false;
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}
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errMsg = "unknown pic model";
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return true;
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}
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void LTOCodeGenerator::setCpu(const char* mCpu)
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{
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_mCpu = mCpu;
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}
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void LTOCodeGenerator::addMustPreserveSymbol(const char* sym)
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{
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_mustPreserveSymbols[sym] = 1;
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}
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bool LTOCodeGenerator::writeMergedModules(const char *path,
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std::string &errMsg) {
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if (determineTarget(errMsg))
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return true;
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// mark which symbols can not be internalized
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applyScopeRestrictions();
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// create output file
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std::string ErrInfo;
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tool_output_file Out(path, ErrInfo,
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raw_fd_ostream::F_Binary);
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if (!ErrInfo.empty()) {
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errMsg = "could not open bitcode file for writing: ";
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errMsg += path;
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return true;
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}
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// write bitcode to it
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WriteBitcodeToFile(_linker.getModule(), Out.os());
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Out.os().close();
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if (Out.os().has_error()) {
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errMsg = "could not write bitcode file: ";
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errMsg += path;
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Out.os().clear_error();
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return true;
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}
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Out.keep();
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return false;
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}
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bool LTOCodeGenerator::compile_to_file(const char** name, std::string& errMsg)
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{
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// make unique temp .o file to put generated object file
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sys::PathWithStatus uniqueObjPath("lto-llvm.o");
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if ( uniqueObjPath.createTemporaryFileOnDisk(false, &errMsg) ) {
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uniqueObjPath.eraseFromDisk();
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return true;
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}
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sys::RemoveFileOnSignal(uniqueObjPath);
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// generate object file
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bool genResult = false;
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tool_output_file objFile(uniqueObjPath.c_str(), errMsg);
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if (!errMsg.empty())
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return true;
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genResult = this->generateObjectFile(objFile.os(), errMsg);
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objFile.os().close();
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if (objFile.os().has_error()) {
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objFile.os().clear_error();
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return true;
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}
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objFile.keep();
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if ( genResult ) {
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uniqueObjPath.eraseFromDisk();
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return true;
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}
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_nativeObjectPath = uniqueObjPath.str();
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*name = _nativeObjectPath.c_str();
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return false;
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}
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const void* LTOCodeGenerator::compile(size_t* length, std::string& errMsg)
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{
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const char *name;
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if (compile_to_file(&name, errMsg))
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return NULL;
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// remove old buffer if compile() called twice
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delete _nativeObjectFile;
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// read .o file into memory buffer
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OwningPtr<MemoryBuffer> BuffPtr;
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if (error_code ec = MemoryBuffer::getFile(name, BuffPtr, -1, false)) {
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errMsg = ec.message();
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return NULL;
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}
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_nativeObjectFile = BuffPtr.take();
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// remove temp files
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sys::Path(_nativeObjectPath).eraseFromDisk();
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// return buffer, unless error
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if ( _nativeObjectFile == NULL )
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return NULL;
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*length = _nativeObjectFile->getBufferSize();
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return _nativeObjectFile->getBufferStart();
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}
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bool LTOCodeGenerator::determineTarget(std::string& errMsg)
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{
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if ( _target == NULL ) {
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std::string Triple = _linker.getModule()->getTargetTriple();
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if (Triple.empty())
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Triple = sys::getDefaultTargetTriple();
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// create target machine from info for merged modules
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const Target *march = TargetRegistry::lookupTarget(Triple, errMsg);
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if ( march == NULL )
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return true;
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// The relocation model is actually a static member of TargetMachine
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// and needs to be set before the TargetMachine is instantiated.
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Reloc::Model RelocModel = Reloc::Default;
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switch( _codeModel ) {
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case LTO_CODEGEN_PIC_MODEL_STATIC:
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RelocModel = Reloc::Static;
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break;
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case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
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RelocModel = Reloc::PIC_;
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break;
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case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
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RelocModel = Reloc::DynamicNoPIC;
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break;
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}
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// construct LTOModule, hand over ownership of module and target
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SubtargetFeatures Features;
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Features.getDefaultSubtargetFeatures(llvm::Triple(Triple));
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std::string FeatureStr = Features.getString();
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_target = march->createTargetMachine(Triple, _mCpu, FeatureStr,
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RelocModel);
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}
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return false;
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}
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void LTOCodeGenerator::applyRestriction(GlobalValue &GV,
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std::vector<const char*> &mustPreserveList,
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SmallPtrSet<GlobalValue*, 8> &asmUsed,
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Mangler &mangler) {
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SmallString<64> Buffer;
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mangler.getNameWithPrefix(Buffer, &GV, false);
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if (GV.isDeclaration())
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return;
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if (_mustPreserveSymbols.count(Buffer))
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mustPreserveList.push_back(GV.getName().data());
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if (_asmUndefinedRefs.count(Buffer))
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asmUsed.insert(&GV);
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}
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static void findUsedValues(GlobalVariable *LLVMUsed,
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SmallPtrSet<GlobalValue*, 8> &UsedValues) {
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if (LLVMUsed == 0) return;
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ConstantArray *Inits = dyn_cast<ConstantArray>(LLVMUsed->getInitializer());
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if (Inits == 0) return;
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for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
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if (GlobalValue *GV =
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dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts()))
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UsedValues.insert(GV);
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}
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void LTOCodeGenerator::applyScopeRestrictions() {
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if (_scopeRestrictionsDone) return;
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Module *mergedModule = _linker.getModule();
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// Start off with a verification pass.
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PassManager passes;
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passes.add(createVerifierPass());
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// mark which symbols can not be internalized
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MCContext Context(*_target->getMCAsmInfo(), *_target->getRegisterInfo(), NULL);
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Mangler mangler(Context, *_target->getTargetData());
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std::vector<const char*> mustPreserveList;
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SmallPtrSet<GlobalValue*, 8> asmUsed;
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for (Module::iterator f = mergedModule->begin(),
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e = mergedModule->end(); f != e; ++f)
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applyRestriction(*f, mustPreserveList, asmUsed, mangler);
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for (Module::global_iterator v = mergedModule->global_begin(),
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e = mergedModule->global_end(); v != e; ++v)
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applyRestriction(*v, mustPreserveList, asmUsed, mangler);
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for (Module::alias_iterator a = mergedModule->alias_begin(),
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e = mergedModule->alias_end(); a != e; ++a)
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applyRestriction(*a, mustPreserveList, asmUsed, mangler);
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GlobalVariable *LLVMCompilerUsed =
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mergedModule->getGlobalVariable("llvm.compiler.used");
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findUsedValues(LLVMCompilerUsed, asmUsed);
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if (LLVMCompilerUsed)
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LLVMCompilerUsed->eraseFromParent();
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llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(_context);
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std::vector<Constant*> asmUsed2;
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for (SmallPtrSet<GlobalValue*, 16>::const_iterator i = asmUsed.begin(),
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e = asmUsed.end(); i !=e; ++i) {
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GlobalValue *GV = *i;
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Constant *c = ConstantExpr::getBitCast(GV, i8PTy);
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asmUsed2.push_back(c);
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}
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llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, asmUsed2.size());
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LLVMCompilerUsed =
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new llvm::GlobalVariable(*mergedModule, ATy, false,
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llvm::GlobalValue::AppendingLinkage,
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llvm::ConstantArray::get(ATy, asmUsed2),
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"llvm.compiler.used");
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LLVMCompilerUsed->setSection("llvm.metadata");
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passes.add(createInternalizePass(mustPreserveList));
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// apply scope restrictions
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passes.run(*mergedModule);
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_scopeRestrictionsDone = true;
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}
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/// Optimize merged modules using various IPO passes
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bool LTOCodeGenerator::generateObjectFile(raw_ostream &out,
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std::string &errMsg) {
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if ( this->determineTarget(errMsg) )
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return true;
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// mark which symbols can not be internalized
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this->applyScopeRestrictions();
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Module* mergedModule = _linker.getModule();
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// if options were requested, set them
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if ( !_codegenOptions.empty() )
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cl::ParseCommandLineOptions(_codegenOptions.size(),
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const_cast<char **>(&_codegenOptions[0]));
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// Instantiate the pass manager to organize the passes.
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PassManager passes;
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// Start off with a verification pass.
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passes.add(createVerifierPass());
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// Add an appropriate TargetData instance for this module...
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passes.add(new TargetData(*_target->getTargetData()));
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PassManagerBuilder().populateLTOPassManager(passes, /*Internalize=*/ false,
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!DisableInline);
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// Make sure everything is still good.
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passes.add(createVerifierPass());
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FunctionPassManager *codeGenPasses = new FunctionPassManager(mergedModule);
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codeGenPasses->add(new TargetData(*_target->getTargetData()));
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formatted_raw_ostream Out(out);
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if (_target->addPassesToEmitFile(*codeGenPasses, Out,
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TargetMachine::CGFT_ObjectFile,
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CodeGenOpt::Aggressive)) {
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errMsg = "target file type not supported";
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return true;
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}
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// Run our queue of passes all at once now, efficiently.
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passes.run(*mergedModule);
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// Run the code generator, and write assembly file
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codeGenPasses->doInitialization();
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for (Module::iterator
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it = mergedModule->begin(), e = mergedModule->end(); it != e; ++it)
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if (!it->isDeclaration())
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codeGenPasses->run(*it);
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codeGenPasses->doFinalization();
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delete codeGenPasses;
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return false; // success
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}
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/// Optimize merged modules using various IPO passes
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void LTOCodeGenerator::setCodeGenDebugOptions(const char* options)
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{
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for (std::pair<StringRef, StringRef> o = getToken(options);
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!o.first.empty(); o = getToken(o.second)) {
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// ParseCommandLineOptions() expects argv[0] to be program name.
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// Lazily add that.
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if ( _codegenOptions.empty() )
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_codegenOptions.push_back("libLTO");
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_codegenOptions.push_back(strdup(o.first.str().c_str()));
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}
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}
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