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/Constants.h"
  20 #include "llvm/DerivedTypes.h"
  21 #include "llvm/Linker.h"
  22 #include "llvm/LLVMContext.h"
  23 #include "llvm/Module.h"
  24 #include "llvm/ModuleProvider.h"
  25 #include "llvm/PassManager.h"
  26 #include "llvm/ADT/StringExtras.h"
  27 #include "llvm/Analysis/Passes.h"
  28 #include "llvm/Analysis/LoopPass.h"
  29 #include "llvm/Analysis/Verifier.h"
  30 #include "llvm/Bitcode/ReaderWriter.h"
  31 #include "llvm/CodeGen/FileWriters.h"
  32 #include "llvm/Support/CommandLine.h"
  33 #include "llvm/Support/FormattedStream.h"
  34 #include "llvm/Support/Mangler.h"
  35 #include "llvm/Support/MemoryBuffer.h"
  36 #include "llvm/Support/StandardPasses.h"
  37 #include "llvm/Support/SystemUtils.h"
  38 #include "llvm/System/Host.h"
  39 #include "llvm/System/Signals.h"
  40 #include "llvm/Target/SubtargetFeature.h"
  41 #include "llvm/Target/TargetOptions.h"
  42 #include "llvm/MC/MCAsmInfo.h"
  43 #include "llvm/Target/TargetData.h"
  44 #include "llvm/Target/TargetMachine.h"
  45 #include "llvm/Target/TargetRegistry.h"
  46 #include "llvm/Target/TargetSelect.h"
  47 #include "llvm/Transforms/IPO.h"
  48 #include "llvm/Transforms/Scalar.h"
  49 #include "llvm/Config/config.h"
  50 #include <cstdlib>
  51 #include <unistd.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     : _context(getGlobalContext()),
  73       _linker("LinkTimeOptimizer", "ld-temp.o", _context), _target(NULL),
  74       _emitDwarfDebugInfo(false), _scopeRestrictionsDone(false),
  75       _codeModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC),
  76       _nativeObjectFile(NULL), _assemblerPath(NULL)
  77 {
  78     InitializeAllTargets();
  79     InitializeAllAsmPrinters();
  80 }
  81
  82 LTOCodeGenerator::~LTOCodeGenerator()
  83 {
  84     delete _target;
  85     delete _nativeObjectFile;
  86 }
  87
  88
  89
  90 bool LTOCodeGenerator::addModule(LTOModule* mod, std::string& errMsg)
  91 {
  92     return _linker.LinkInModule(mod->getLLVVMModule(), &errMsg);
  93 }
  94
  95
  96 bool LTOCodeGenerator::setDebugInfo(lto_debug_model debug, std::string& errMsg)
  97 {
  98     switch (debug) {
  99         case LTO_DEBUG_MODEL_NONE:
 100             _emitDwarfDebugInfo = false;
 101             return false;
 102
 103         case LTO_DEBUG_MODEL_DWARF:
 104             _emitDwarfDebugInfo = true;
 105             return false;
 106     }
 107     errMsg = "unknown debug format";
 108     return true;
 109 }
 110
 111
 112 bool LTOCodeGenerator::setCodePICModel(lto_codegen_model model,
 113                                        std::string& errMsg)
 114 {
 115     switch (model) {
 116         case LTO_CODEGEN_PIC_MODEL_STATIC:
 117         case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
 118         case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
 119             _codeModel = model;
 120             return false;
 121     }
 122     errMsg = "unknown pic model";
 123     return true;
 124 }
 125
 126 void LTOCodeGenerator::setAssemblerPath(const char* path)
 127 {
 128     if ( _assemblerPath )
 129         delete _assemblerPath;
 130     _assemblerPath = new sys::Path(path);
 131 }
 132
 133 void LTOCodeGenerator::addMustPreserveSymbol(const char* sym)
 134 {
 135     _mustPreserveSymbols[sym] = 1;
 136 }
 137
 138
 139 bool LTOCodeGenerator::writeMergedModules(const char *path,
 140                                           std::string &errMsg) {
 141   if (determineTarget(errMsg))
 142     return true;
 143
 144   // mark which symbols can not be internalized
 145   applyScopeRestrictions();
 146
 147   // create output file
 148   std::string ErrInfo;
 149   raw_fd_ostream Out(path, ErrInfo,
 150                      raw_fd_ostream::F_Force|raw_fd_ostream::F_Binary);
 151   if (!ErrInfo.empty()) {
 152     errMsg = "could not open bitcode file for writing: ";
 153     errMsg += path;
 154     return true;
 155   }
 156
 157   // write bitcode to it
 158   WriteBitcodeToFile(_linker.getModule(), Out);
 159
 160   if (Out.has_error()) {
 161     errMsg = "could not write bitcode file: ";
 162     errMsg += path;
 163     return true;
 164   }
 165
 166   return false;
 167 }
 168
 169
 170 const void* LTOCodeGenerator::compile(size_t* length, std::string& errMsg)
 171 {
 172     // make unique temp .s file to put generated assembly code
 173     sys::Path uniqueAsmPath("lto-llvm.s");
 174     if ( uniqueAsmPath.createTemporaryFileOnDisk(true, &errMsg) )
 175         return NULL;
 176     sys::RemoveFileOnSignal(uniqueAsmPath);
 177
 178     // generate assembly code
 179     bool genResult = false;
 180     {
 181       raw_fd_ostream asmFD(uniqueAsmPath.c_str(), errMsg,
 182                            raw_fd_ostream::F_Force);
 183       formatted_raw_ostream asmFile(asmFD);
 184       if (!errMsg.empty())
 185         return NULL;
 186       genResult = this->generateAssemblyCode(asmFile, errMsg);
 187     }
 188     if ( genResult ) {
 189         if ( uniqueAsmPath.exists() )
 190             uniqueAsmPath.eraseFromDisk();
 191         return NULL;
 192     }
 193
 194     // make unique temp .o file to put generated object file
 195     sys::PathWithStatus uniqueObjPath("lto-llvm.o");
 196     if ( uniqueObjPath.createTemporaryFileOnDisk(true, &errMsg) ) {
 197         if ( uniqueAsmPath.exists() )
 198             uniqueAsmPath.eraseFromDisk();
 199         return NULL;
 200     }
 201     sys::RemoveFileOnSignal(uniqueObjPath);
 202
 203     // assemble the assembly code
 204     const std::string& uniqueObjStr = uniqueObjPath.toString();
 205     bool asmResult = this->assemble(uniqueAsmPath.toString(),
 206                                                         uniqueObjStr, errMsg);
 207     if ( !asmResult ) {
 208         // remove old buffer if compile() called twice
 209         delete _nativeObjectFile;
 210
 211         // read .o file into memory buffer
 212         _nativeObjectFile = MemoryBuffer::getFile(uniqueObjStr.c_str(),&errMsg);
 213     }
 214
 215     // remove temp files
 216     uniqueAsmPath.eraseFromDisk();
 217     uniqueObjPath.eraseFromDisk();
 218
 219     // return buffer, unless error
 220     if ( _nativeObjectFile == NULL )
 221         return NULL;
 222     *length = _nativeObjectFile->getBufferSize();
 223     return _nativeObjectFile->getBufferStart();
 224 }
 225
 226
 227 bool LTOCodeGenerator::assemble(const std::string& asmPath,
 228                                 const std::string& objPath, std::string& errMsg)
 229 {
 230     sys::Path tool;
 231     bool needsCompilerOptions = true;
 232     if ( _assemblerPath ) {
 233         tool = *_assemblerPath;
 234         needsCompilerOptions = false;
 235     } else {
 236         // find compiler driver
 237         tool = sys::Program::FindProgramByName("gcc");
 238         if ( tool.isEmpty() ) {
 239             errMsg = "can't locate gcc";
 240             return true;
 241         }
 242     }
 243
 244     // build argument list
 245     std::vector<const char*> args;
 246     std::string targetTriple = _linker.getModule()->getTargetTriple();
 247     args.push_back(tool.c_str());
 248     if ( targetTriple.find("darwin") != std::string::npos ) {
 249         // darwin specific command line options
 250         if (strncmp(targetTriple.c_str(), "i386-apple-", 11) == 0) {
 251             args.push_back("-arch");
 252             args.push_back("i386");
 253         }
 254         else if (strncmp(targetTriple.c_str(), "x86_64-apple-", 13) == 0) {
 255             args.push_back("-arch");
 256             args.push_back("x86_64");
 257         }
 258         else if (strncmp(targetTriple.c_str(), "powerpc-apple-", 14) == 0) {
 259             args.push_back("-arch");
 260             args.push_back("ppc");
 261         }
 262         else if (strncmp(targetTriple.c_str(), "powerpc64-apple-", 16) == 0) {
 263             args.push_back("-arch");
 264             args.push_back("ppc64");
 265         }
 266         else if (strncmp(targetTriple.c_str(), "arm-apple-", 10) == 0) {
 267             args.push_back("-arch");
 268             args.push_back("arm");
 269         }
 270         else if ((strncmp(targetTriple.c_str(), "armv4t-apple-", 13) == 0) ||
 271                  (strncmp(targetTriple.c_str(), "thumbv4t-apple-", 15) == 0)) {
 272             args.push_back("-arch");
 273             args.push_back("armv4t");
 274         }
 275         else if ((strncmp(targetTriple.c_str(), "armv5-apple-", 12) == 0) ||
 276                  (strncmp(targetTriple.c_str(), "armv5e-apple-", 13) == 0) ||
 277                  (strncmp(targetTriple.c_str(), "thumbv5-apple-", 14) == 0) ||
 278                  (strncmp(targetTriple.c_str(), "thumbv5e-apple-", 15) == 0)) {
 279             args.push_back("-arch");
 280             args.push_back("armv5");
 281         }
 282         else if ((strncmp(targetTriple.c_str(), "armv6-apple-", 12) == 0) ||
 283                  (strncmp(targetTriple.c_str(), "thumbv6-apple-", 14) == 0)) {
 284             args.push_back("-arch");
 285             args.push_back("armv6");
 286         }
 287         else if ((strncmp(targetTriple.c_str(), "armv7-apple-", 12) == 0) ||
 288                  (strncmp(targetTriple.c_str(), "thumbv7-apple-", 14) == 0)) {
 289             args.push_back("-arch");
 290             args.push_back("armv7");
 291         }
 292         // add -static to assembler command line when code model requires
 293         if ( (_assemblerPath != NULL) && (_codeModel == LTO_CODEGEN_PIC_MODEL_STATIC) )
 294             args.push_back("-static");
 295     }
 296     if ( needsCompilerOptions ) {
 297         args.push_back("-c");
 298         args.push_back("-x");
 299         args.push_back("assembler");
 300     }
 301     args.push_back("-o");
 302     args.push_back(objPath.c_str());
 303     args.push_back(asmPath.c_str());
 304     args.push_back(0);
 305
 306     // invoke assembler
 307     if ( sys::Program::ExecuteAndWait(tool, &args[0], 0, 0, 0, 0, &errMsg) ) {
 308         errMsg = "error in assembly";
 309         return true;
 310     }
 311     return false; // success
 312 }
 313
 314
 315
 316 bool LTOCodeGenerator::determineTarget(std::string& errMsg)
 317 {
 318     if ( _target == NULL ) {
 319         std::string Triple = _linker.getModule()->getTargetTriple();
 320         if (Triple.empty())
 321           Triple = sys::getHostTriple();
 322
 323         // create target machine from info for merged modules
 324         const Target *march = TargetRegistry::lookupTarget(Triple, errMsg);
 325         if ( march == NULL )
 326             return true;
 327
 328         // The relocation model is actually a static member of TargetMachine
 329         // and needs to be set before the TargetMachine is instantiated.
 330         switch( _codeModel ) {
 331         case LTO_CODEGEN_PIC_MODEL_STATIC:
 332             TargetMachine::setRelocationModel(Reloc::Static);
 333             break;
 334         case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
 335             TargetMachine::setRelocationModel(Reloc::PIC_);
 336             break;
 337         case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
 338             TargetMachine::setRelocationModel(Reloc::DynamicNoPIC);
 339             break;
 340         }
 341
 342         // construct LTModule, hand over ownership of module and target
 343         std::string FeatureStr = getFeatureString(Triple.c_str());
 344         _target = march->createTargetMachine(Triple, FeatureStr);
 345     }
 346     return false;
 347 }
 348
 349 void LTOCodeGenerator::applyScopeRestrictions()
 350 {
 351     if ( !_scopeRestrictionsDone ) {
 352         Module* mergedModule = _linker.getModule();
 353
 354         // Start off with a verification pass.
 355         PassManager passes;
 356         passes.add(createVerifierPass());
 357
 358         // mark which symbols can not be internalized
 359         if ( !_mustPreserveSymbols.empty() ) {
 360             Mangler mangler(*mergedModule,
 361                                 _target->getMCAsmInfo()->getGlobalPrefix());
 362             std::vector<const char*> mustPreserveList;
 363             for (Module::iterator f = mergedModule->begin(),
 364                                         e = mergedModule->end(); f != e; ++f) {
 365                 if ( !f->isDeclaration()
 366                   && _mustPreserveSymbols.count(mangler.getMangledName(f)) )
 367                   mustPreserveList.push_back(::strdup(f->getNameStr().c_str()));
 368             }
 369             for (Module::global_iterator v = mergedModule->global_begin(),
 370                                  e = mergedModule->global_end(); v !=  e; ++v) {
 371                 if ( !v->isDeclaration()
 372                   && _mustPreserveSymbols.count(mangler.getMangledName(v)) )
 373                   mustPreserveList.push_back(::strdup(v->getNameStr().c_str()));
 374             }
 375             passes.add(createInternalizePass(mustPreserveList));
 376         }
 377         // apply scope restrictions
 378         passes.run(*mergedModule);
 379
 380         _scopeRestrictionsDone = true;
 381     }
 382 }
 383
 384 /// Optimize merged modules using various IPO passes
 385 bool LTOCodeGenerator::generateAssemblyCode(formatted_raw_ostream& out,
 386                                             std::string& errMsg)
 387 {
 388     if ( this->determineTarget(errMsg) )
 389         return true;
 390
 391     // mark which symbols can not be internalized
 392     this->applyScopeRestrictions();
 393
 394     Module* mergedModule = _linker.getModule();
 395
 396     // If target supports exception handling then enable it now.
 397     switch (_target->getMCAsmInfo()->getExceptionHandlingType()) {
 398     case ExceptionHandling::Dwarf:
 399       llvm::DwarfExceptionHandling = true;
 400       break;
 401     case ExceptionHandling::SjLj:
 402       llvm::SjLjExceptionHandling = true;
 403       break;
 404     case ExceptionHandling::None:
 405       break;
 406     default:
 407       assert (0 && "Unknown exception handling model!");
 408     }
 409
 410     // if options were requested, set them
 411     if ( !_codegenOptions.empty() )
 412         cl::ParseCommandLineOptions(_codegenOptions.size(),
 413                                                 (char**)&_codegenOptions[0]);
 414
 415     // Instantiate the pass manager to organize the passes.
 416     PassManager passes;
 417
 418     // Start off with a verification pass.
 419     passes.add(createVerifierPass());
 420
 421     // Add an appropriate TargetData instance for this module...
 422     passes.add(new TargetData(*_target->getTargetData()));
 423
 424     createStandardLTOPasses(&passes, /*Internalize=*/ false, !DisableInline,
 425                             /*VerifyEach=*/ false);
 426
 427     // Make sure everything is still good.
 428     passes.add(createVerifierPass());
 429
 430     FunctionPassManager* codeGenPasses =
 431             new FunctionPassManager(new ExistingModuleProvider(mergedModule));
 432
 433     codeGenPasses->add(new TargetData(*_target->getTargetData()));
 434
 435     ObjectCodeEmitter* oce = NULL;
 436
 437     switch (_target->addPassesToEmitFile(*codeGenPasses, out,
 438                                          TargetMachine::AssemblyFile,
 439                                          CodeGenOpt::Aggressive)) {
 440         case FileModel::MachOFile:
 441             oce = AddMachOWriter(*codeGenPasses, out, *_target);
 442             break;
 443         case FileModel::ElfFile:
 444             oce = AddELFWriter(*codeGenPasses, out, *_target);
 445             break;
 446         case FileModel::AsmFile:
 447             break;
 448         case FileModel::Error:
 449         case FileModel::None:
 450             errMsg = "target file type not supported";
 451             return true;
 452     }
 453
 454     if (_target->addPassesToEmitFileFinish(*codeGenPasses, oce,
 455                                            CodeGenOpt::Aggressive)) {
 456         errMsg = "target does not support generation of this file type";
 457         return true;
 458     }
 459
 460     // Run our queue of passes all at once now, efficiently.
 461     passes.run(*mergedModule);
 462
 463     // Run the code generator, and write assembly file
 464     codeGenPasses->doInitialization();
 465
 466     for (Module::iterator
 467            it = mergedModule->begin(), e = mergedModule->end(); it != e; ++it)
 468       if (!it->isDeclaration())
 469         codeGenPasses->run(*it);
 470
 471     codeGenPasses->doFinalization();
 472
 473     out.flush();
 474
 475     return false; // success
 476 }
 477
 478
 479 /// Optimize merged modules using various IPO passes
 480 void LTOCodeGenerator::setCodeGenDebugOptions(const char* options)
 481 {
 482     std::string ops(options);
 483     for (std::string o = getToken(ops); !o.empty(); o = getToken(ops)) {
 484         // ParseCommandLineOptions() expects argv[0] to be program name.
 485         // Lazily add that.
 486         if ( _codegenOptions.empty() )
 487             _codegenOptions.push_back("libLTO");
 488         _codegenOptions.push_back(strdup(o.c_str()));
 489     }
 490 }