tools/lto/LTOCodeGenerator.cpp

   1 //===-LTOCodeGenerator.cpp - LLVM Link Time Optimizer ---------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the Link Time Optimization library. This library is
  11 // intended to be used by linker to optimize code at link time.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "LTOModule.h"
  16 #include "LTOCodeGenerator.h"
  17
  18
  19 #include "llvm/Module.h"
  20 #include "llvm/PassManager.h"
  21 #include "llvm/Linker.h"
  22 #include "llvm/Constants.h"
  23 #include "llvm/DerivedTypes.h"
  24 #include "llvm/ModuleProvider.h"
  25 #include "llvm/Bitcode/ReaderWriter.h"
  26 #include "llvm/Support/CommandLine.h"
  27 #include "llvm/Support/Mangler.h"
  28 #include "llvm/Support/MemoryBuffer.h"
  29 #include "llvm/Support/StandardPasses.h"
  30 #include "llvm/Support/SystemUtils.h"
  31 #include "llvm/Support/raw_ostream.h"
  32 #include "llvm/System/Signals.h"
  33 #include "llvm/Analysis/Passes.h"
  34 #include "llvm/Analysis/LoopPass.h"
  35 #include "llvm/Analysis/Verifier.h"
  36 #include "llvm/CodeGen/FileWriters.h"
  37 #include "llvm/Target/SubtargetFeature.h"
  38 #include "llvm/Target/TargetOptions.h"
  39 #include "llvm/Target/TargetData.h"
  40 #include "llvm/Target/TargetMachine.h"
  41 #include "llvm/Target/TargetMachineRegistry.h"
  42 #include "llvm/Target/TargetAsmInfo.h"
  43 #include "llvm/Transforms/IPO.h"
  44 #include "llvm/Transforms/Scalar.h"
  45 #include "llvm/ADT/StringExtras.h"
  46 #include "llvm/Config/config.h"
  47
  48
  49 #include <fstream>
  50 #include <unistd.h>
  51 #include <stdlib.h>
  52 #include <fcntl.h>
  53
  54
  55 using namespace llvm;
  56
  57 static cl::opt<bool> DisableInline("disable-inlining",
  58   cl::desc("Do not run the inliner pass"));
  59
  60
  61 const char* LTOCodeGenerator::getVersionString()
  62 {
  63 #ifdef LLVM_VERSION_INFO
  64     return PACKAGE_NAME " version " PACKAGE_VERSION ", " LLVM_VERSION_INFO;
  65 #else
  66     return PACKAGE_NAME " version " PACKAGE_VERSION;
  67 #endif
  68 }
  69
  70
  71 LTOCodeGenerator::LTOCodeGenerator()
  72     : _linker("LinkTimeOptimizer", "ld-temp.o"), _target(NULL),
  73       _emitDwarfDebugInfo(false), _scopeRestrictionsDone(false),
  74       _codeModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC),
  75       _nativeObjectFile(NULL), _gccPath(NULL)
  76 {
  77
  78 }
  79
  80 LTOCodeGenerator::~LTOCodeGenerator()
  81 {
  82     delete _target;
  83     delete _nativeObjectFile;
  84 }
  85
  86
  87
  88 bool LTOCodeGenerator::addModule(LTOModule* mod, std::string& errMsg)
  89 {
  90     return _linker.LinkInModule(mod->getLLVVMModule(), &errMsg);
  91 }
  92
  93
  94 bool LTOCodeGenerator::setDebugInfo(lto_debug_model debug, std::string& errMsg)
  95 {
  96     switch (debug) {
  97         case LTO_DEBUG_MODEL_NONE:
  98             _emitDwarfDebugInfo = false;
  99             return false;
 100
 101         case LTO_DEBUG_MODEL_DWARF:
 102             _emitDwarfDebugInfo = true;
 103             return false;
 104     }
 105     errMsg = "unknown debug format";
 106     return true;
 107 }
 108
 109
 110 bool LTOCodeGenerator::setCodePICModel(lto_codegen_model model,
 111                                                         std::string& errMsg)
 112 {
 113     switch (model) {
 114         case LTO_CODEGEN_PIC_MODEL_STATIC:
 115         case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
 116         case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
 117             _codeModel = model;
 118             return false;
 119     }
 120     errMsg = "unknown pic model";
 121     return true;
 122 }
 123
 124 void LTOCodeGenerator::setGccPath(const char* path)
 125 {
 126     if ( _gccPath )
 127         delete _gccPath;
 128     _gccPath = new sys::Path(path);
 129 }
 130
 131 void LTOCodeGenerator::addMustPreserveSymbol(const char* sym)
 132 {
 133     _mustPreserveSymbols[sym] = 1;
 134 }
 135
 136
 137 bool LTOCodeGenerator::writeMergedModules(const char* path, std::string& errMsg)
 138 {
 139     if ( this->determineTarget(errMsg) )
 140         return true;
 141
 142     // mark which symbols can not be internalized
 143     this->applyScopeRestrictions();
 144
 145     // create output file
 146     std::ofstream out(path, std::ios_base::out|std::ios::trunc|std::ios::binary);
 147     if ( out.fail() ) {
 148         errMsg = "could not open bitcode file for writing: ";
 149         errMsg += path;
 150         return true;
 151     }
 152
 153     // write bitcode to it
 154     WriteBitcodeToFile(_linker.getModule(), out);
 155     if ( out.fail() ) {
 156         errMsg = "could not write bitcode file: ";
 157         errMsg += path;
 158         return true;
 159     }
 160
 161     return false;
 162 }
 163
 164
 165 const void* LTOCodeGenerator::compile(size_t* length, std::string& errMsg)
 166 {
 167     // make unique temp .s file to put generated assembly code
 168     sys::Path uniqueAsmPath("lto-llvm.s");
 169     if ( uniqueAsmPath.createTemporaryFileOnDisk(true, &errMsg) )
 170         return NULL;
 171     sys::RemoveFileOnSignal(uniqueAsmPath);
 172
 173     // generate assembly code
 174     bool genResult = false;
 175     {
 176       raw_fd_ostream asmFile(uniqueAsmPath.c_str(), false, errMsg);
 177       if (!errMsg.empty())
 178         return NULL;
 179       genResult = this->generateAssemblyCode(asmFile, errMsg);
 180     }
 181     if ( genResult ) {
 182         if ( uniqueAsmPath.exists() )
 183             uniqueAsmPath.eraseFromDisk();
 184         return NULL;
 185     }
 186
 187     // make unique temp .o file to put generated object file
 188     sys::PathWithStatus uniqueObjPath("lto-llvm.o");
 189     if ( uniqueObjPath.createTemporaryFileOnDisk(true, &errMsg) ) {
 190         if ( uniqueAsmPath.exists() )
 191             uniqueAsmPath.eraseFromDisk();
 192         return NULL;
 193     }
 194     sys::RemoveFileOnSignal(uniqueObjPath);
 195
 196     // assemble the assembly code
 197     const std::string& uniqueObjStr = uniqueObjPath.toString();
 198     bool asmResult = this->assemble(uniqueAsmPath.toString(),
 199                                                         uniqueObjStr, errMsg);
 200     if ( !asmResult ) {
 201         // remove old buffer if compile() called twice
 202         delete _nativeObjectFile;
 203
 204         // read .o file into memory buffer
 205         _nativeObjectFile = MemoryBuffer::getFile(uniqueObjStr.c_str(),&errMsg);
 206     }
 207
 208     // remove temp files
 209     uniqueAsmPath.eraseFromDisk();
 210     uniqueObjPath.eraseFromDisk();
 211
 212     // return buffer, unless error
 213     if ( _nativeObjectFile == NULL )
 214         return NULL;
 215     *length = _nativeObjectFile->getBufferSize();
 216     return _nativeObjectFile->getBufferStart();
 217 }
 218
 219
 220 bool LTOCodeGenerator::assemble(const std::string& asmPath,
 221                                 const std::string& objPath, std::string& errMsg)
 222 {
 223     sys::Path gcc;
 224     if ( _gccPath ) {
 225         gcc = *_gccPath;
 226     } else {
 227         // find compiler driver
 228         gcc = sys::Program::FindProgramByName("gcc");
 229         if ( gcc.isEmpty() ) {
 230             errMsg = "can't locate gcc";
 231             return true;
 232         }
 233     }
 234
 235     // build argument list
 236     std::vector<const char*> args;
 237     std::string targetTriple = _linker.getModule()->getTargetTriple();
 238     args.push_back(gcc.c_str());
 239     if ( targetTriple.find("darwin") != targetTriple.size() ) {
 240         if (strncmp(targetTriple.c_str(), "i386-apple-", 11) == 0) {
 241             args.push_back("-arch");
 242             args.push_back("i386");
 243         }
 244         else if (strncmp(targetTriple.c_str(), "x86_64-apple-", 13) == 0) {
 245             args.push_back("-arch");
 246             args.push_back("x86_64");
 247         }
 248         else if (strncmp(targetTriple.c_str(), "powerpc-apple-", 14) == 0) {
 249             args.push_back("-arch");
 250             args.push_back("ppc");
 251         }
 252         else if (strncmp(targetTriple.c_str(), "powerpc64-apple-", 16) == 0) {
 253             args.push_back("-arch");
 254             args.push_back("ppc64");
 255         }
 256         else if (strncmp(targetTriple.c_str(), "arm-apple-", 10) == 0) {
 257             args.push_back("-arch");
 258             args.push_back("arm");
 259         }
 260         else if ((strncmp(targetTriple.c_str(), "armv4t-apple-", 13) == 0) ||
 261                  (strncmp(targetTriple.c_str(), "thumbv4t-apple-", 15) == 0)) {
 262             args.push_back("-arch");
 263             args.push_back("armv4t");
 264         }
 265         else if ((strncmp(targetTriple.c_str(), "armv5-apple-", 12) == 0) ||
 266                  (strncmp(targetTriple.c_str(), "armv5e-apple-", 13) == 0) ||
 267                  (strncmp(targetTriple.c_str(), "thumbv5-apple-", 14) == 0) ||
 268                  (strncmp(targetTriple.c_str(), "thumbv5e-apple-", 15) == 0)) {
 269             args.push_back("-arch");
 270             args.push_back("armv5");
 271         }
 272         else if ((strncmp(targetTriple.c_str(), "armv6-apple-", 12) == 0) ||
 273                  (strncmp(targetTriple.c_str(), "thumbv6-apple-", 14) == 0)) {
 274             args.push_back("-arch");
 275             args.push_back("armv6");
 276         }
 277     }
 278     args.push_back("-c");
 279     args.push_back("-x");
 280     args.push_back("assembler");
 281     args.push_back("-o");
 282     args.push_back(objPath.c_str());
 283     args.push_back(asmPath.c_str());
 284     args.push_back(0);
 285
 286     // invoke assembler
 287     if ( sys::Program::ExecuteAndWait(gcc, &args[0], 0, 0, 0, 0, &errMsg) ) {
 288         errMsg = "error in assembly";
 289         return true;
 290     }
 291     return false; // success
 292 }
 293
 294
 295
 296 bool LTOCodeGenerator::determineTarget(std::string& errMsg)
 297 {
 298     if ( _target == NULL ) {
 299         // create target machine from info for merged modules
 300         Module* mergedModule = _linker.getModule();
 301         const TargetMachineRegistry::entry* march =
 302           TargetMachineRegistry::getClosestStaticTargetForModule(
 303                                                        *mergedModule, errMsg);
 304         if ( march == NULL )
 305             return true;
 306
 307         // construct LTModule, hand over ownership of module and target
 308         std::string FeatureStr =
 309           getFeatureString(_linker.getModule()->getTargetTriple().c_str());
 310         _target = march->CtorFn(*mergedModule, FeatureStr.c_str());
 311     }
 312     return false;
 313 }
 314
 315 void LTOCodeGenerator::applyScopeRestrictions()
 316 {
 317     if ( !_scopeRestrictionsDone ) {
 318         Module* mergedModule = _linker.getModule();
 319
 320         // Start off with a verification pass.
 321         PassManager passes;
 322         passes.add(createVerifierPass());
 323
 324         // mark which symbols can not be internalized
 325         if ( !_mustPreserveSymbols.empty() ) {
 326             Mangler mangler(*mergedModule,
 327                                 _target->getTargetAsmInfo()->getGlobalPrefix());
 328             std::vector<const char*> mustPreserveList;
 329             for (Module::iterator f = mergedModule->begin(),
 330                                         e = mergedModule->end(); f != e; ++f) {
 331                 if ( !f->isDeclaration()
 332                   && _mustPreserveSymbols.count(mangler.getValueName(f)) )
 333                     mustPreserveList.push_back(::strdup(f->getName().c_str()));
 334             }
 335             for (Module::global_iterator v = mergedModule->global_begin(),
 336                                  e = mergedModule->global_end(); v !=  e; ++v) {
 337                 if ( !v->isDeclaration()
 338                   && _mustPreserveSymbols.count(mangler.getValueName(v)) )
 339                     mustPreserveList.push_back(::strdup(v->getName().c_str()));
 340             }
 341             passes.add(createInternalizePass(mustPreserveList));
 342         }
 343         // apply scope restrictions
 344         passes.run(*mergedModule);
 345
 346         _scopeRestrictionsDone = true;
 347     }
 348 }
 349
 350 /// Optimize merged modules using various IPO passes
 351 bool LTOCodeGenerator::generateAssemblyCode(raw_ostream& out,
 352                                             std::string& errMsg)
 353 {
 354     if (  this->determineTarget(errMsg) )
 355         return true;
 356
 357     // mark which symbols can not be internalized
 358     this->applyScopeRestrictions();
 359
 360     Module* mergedModule = _linker.getModule();
 361
 362      // If target supports exception handling then enable it now.
 363     if ( _target->getTargetAsmInfo()->doesSupportExceptionHandling() )
 364         llvm::ExceptionHandling = true;
 365
 366     // set codegen model
 367     switch( _codeModel ) {
 368         case LTO_CODEGEN_PIC_MODEL_STATIC:
 369             _target->setRelocationModel(Reloc::Static);
 370             break;
 371         case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
 372             _target->setRelocationModel(Reloc::PIC_);
 373             break;
 374         case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
 375             _target->setRelocationModel(Reloc::DynamicNoPIC);
 376             break;
 377     }
 378
 379     // if options were requested, set them
 380     if ( !_codegenOptions.empty() )
 381         cl::ParseCommandLineOptions(_codegenOptions.size(),
 382                                                 (char**)&_codegenOptions[0]);
 383
 384     // Instantiate the pass manager to organize the passes.
 385     PassManager passes;
 386
 387     // Start off with a verification pass.
 388     passes.add(createVerifierPass());
 389
 390     // Add an appropriate TargetData instance for this module...
 391     passes.add(new TargetData(*_target->getTargetData()));
 392
 393     createStandardLTOPasses(&passes, /*Internalize=*/ false, !DisableInline,
 394                             /*RunSecondGlobalOpt=*/ false,
 395                             /*VerifyEach=*/ false);
 396
 397     // Make sure everything is still good.
 398     passes.add(createVerifierPass());
 399
 400     FunctionPassManager* codeGenPasses =
 401             new FunctionPassManager(new ExistingModuleProvider(mergedModule));
 402
 403     codeGenPasses->add(new TargetData(*_target->getTargetData()));
 404
 405     MachineCodeEmitter* mce = NULL;
 406
 407     switch (_target->addPassesToEmitFile(*codeGenPasses, out,
 408                                          TargetMachine::AssemblyFile,
 409                                          CodeGenOpt::Aggressive)) {
 410         case FileModel::MachOFile:
 411             mce = AddMachOWriter(*codeGenPasses, out, *_target);
 412             break;
 413         case FileModel::ElfFile:
 414             mce = AddELFWriter(*codeGenPasses, out, *_target);
 415             break;
 416         case FileModel::AsmFile:
 417             break;
 418         case FileModel::Error:
 419         case FileModel::None:
 420             errMsg = "target file type not supported";
 421             return true;
 422     }
 423
 424     if (_target->addPassesToEmitFileFinish(*codeGenPasses, mce,
 425                                            CodeGenOpt::Aggressive)) {
 426         errMsg = "target does not support generation of this file type";
 427         return true;
 428     }
 429
 430     // Run our queue of passes all at once now, efficiently.
 431     passes.run(*mergedModule);
 432
 433     // Run the code generator, and write assembly file
 434     codeGenPasses->doInitialization();
 435
 436     for (Module::iterator
 437            it = mergedModule->begin(), e = mergedModule->end(); it != e; ++it)
 438       if (!it->isDeclaration())
 439         codeGenPasses->run(*it);
 440
 441     codeGenPasses->doFinalization();
 442     return false; // success
 443 }
 444
 445
 446 /// Optimize merged modules using various IPO passes
 447 void LTOCodeGenerator::setCodeGenDebugOptions(const char* options)
 448 {
 449     std::string ops(options);
 450     for (std::string o = getToken(ops); !o.empty(); o = getToken(ops)) {
 451         // ParseCommandLineOptions() expects argv[0] to be program name.
 452         // Lazily add that.
 453         if ( _codegenOptions.empty() )
 454             _codegenOptions.push_back("libLTO");
 455         _codegenOptions.push_back(strdup(o.c_str()));
 456     }
 457 }