mirror of
https://github.com/c64scene-ar/llvm-6502.git
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38c4e53549
uses. The result produced by the streamer is used to give the linker more accurate information and to add to llvm.compiler.used. The second improvement removes the need for the user to add __attribute__((used)) to functions only used in inline asm. The first one lets us build firefox with LTO on Darwin :-) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126830 91177308-0d34-0410-b5e6-96231b3b80d8
416 lines
13 KiB
C++
416 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/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/Target/Mangler.h"
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#include "llvm/Target/SubtargetFeature.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/TargetRegistry.h"
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#include "llvm/Target/TargetSelect.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/StandardPasses.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/system_error.h"
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#include "llvm/Config/config.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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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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const void* LTOCodeGenerator::compile(size_t* length, 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 NULL;
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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 NULL;
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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 NULL;
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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 NULL;
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}
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const std::string& uniqueObjStr = uniqueObjPath.str();
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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(uniqueObjStr.c_str(),BuffPtr))
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errMsg = ec.message();
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_nativeObjectFile = BuffPtr.take();
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// remove temp files
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uniqueObjPath.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::getHostTriple();
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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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switch( _codeModel ) {
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case LTO_CODEGEN_PIC_MODEL_STATIC:
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TargetMachine::setRelocationModel(Reloc::Static);
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break;
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case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
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TargetMachine::setRelocationModel(Reloc::PIC_);
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break;
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case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
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TargetMachine::setRelocationModel(Reloc::DynamicNoPIC);
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break;
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}
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// construct LTModule, hand over ownership of module and target
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SubtargetFeatures Features;
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Features.getDefaultSubtargetFeatures(_mCpu, llvm::Triple(Triple));
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std::string FeatureStr = Features.getString();
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_target = march->createTargetMachine(Triple, FeatureStr);
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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(), 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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const 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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{
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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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createStandardLTOPasses(&passes, /*Internalize=*/ false, !DisableInline,
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/*VerifyEach=*/ false);
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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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