tools/opt/opt.cpp

   1 //===- opt.cpp - The LLVM Modular Optimizer -------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by the LLVM research group and is distributed under
   6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Optimizations may be specified an arbitrary number of times on the command
  11 // line, They are run in the order specified.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/Module.h"
  16 #include "llvm/PassManager.h"
  17 #include "llvm/Bitcode/ReaderWriter.h"
  18 #include "llvm/Assembly/PrintModulePass.h"
  19 #include "llvm/Analysis/Verifier.h"
  20 #include "llvm/Analysis/LoopPass.h"
  21 #include "llvm/Target/TargetData.h"
  22 #include "llvm/Target/TargetMachine.h"
  23 #include "llvm/Support/PassNameParser.h"
  24 #include "llvm/System/Signals.h"
  25 #include "llvm/Support/ManagedStatic.h"
  26 #include "llvm/Support/MemoryBuffer.h"
  27 #include "llvm/Support/PluginLoader.h"
  28 #include "llvm/Support/Streams.h"
  29 #include "llvm/Support/SystemUtils.h"
  30 #include "llvm/LinkAllPasses.h"
  31 #include "llvm/LinkAllVMCore.h"
  32 #include <iostream>
  33 #include <fstream>
  34 #include <memory>
  35 #include <algorithm>
  36 using namespace llvm;
  37
  38 // The OptimizationList is automatically populated with registered Passes by the
  39 // PassNameParser.
  40 //
  41 static cl::list<const PassInfo*, bool, PassNameParser>
  42 PassList(cl::desc("Optimizations available:"));
  43
  44 // Other command line options...
  45 //
  46 static cl::opt<std::string>
  47 InputFilename(cl::Positional, cl::desc("<input bytecode file>"),
  48     cl::init("-"), cl::value_desc("filename"));
  49
  50 static cl::opt<std::string>
  51 OutputFilename("o", cl::desc("Override output filename"),
  52                cl::value_desc("filename"), cl::init("-"));
  53
  54 static cl::opt<bool>
  55 Force("f", cl::desc("Overwrite output files"));
  56
  57 static cl::opt<bool>
  58 PrintEachXForm("p", cl::desc("Print module after each transformation"));
  59
  60 static cl::opt<bool>
  61 NoOutput("disable-output",
  62          cl::desc("Do not write result bytecode file"), cl::Hidden);
  63
  64 static cl::opt<bool>
  65 NoVerify("disable-verify", cl::desc("Do not verify result module"), cl::Hidden);
  66
  67 static cl::opt<bool>
  68 VerifyEach("verify-each", cl::desc("Verify after each transform"));
  69
  70 static cl::opt<bool>
  71 StripDebug("strip-debug",
  72            cl::desc("Strip debugger symbol info from translation unit"));
  73
  74 static cl::opt<bool>
  75 DisableInline("disable-inlining", cl::desc("Do not run the inliner pass"));
  76
  77 static cl::opt<bool>
  78 DisableOptimizations("disable-opt",
  79                      cl::desc("Do not run any optimization passes"));
  80
  81 static cl::opt<bool>
  82 StandardCompileOpts("std-compile-opts",
  83                    cl::desc("Include the standard compile time optimizations"));
  84
  85 static cl::opt<bool>
  86 Quiet("q", cl::desc("Obsolete option"), cl::Hidden);
  87
  88 static cl::alias
  89 QuietA("quiet", cl::desc("Alias for -q"), cl::aliasopt(Quiet));
  90
  91 static cl::opt<bool>
  92 AnalyzeOnly("analyze", cl::desc("Only perform analysis, no optimization"));
  93
  94 // ---------- Define Printers for module and function passes ------------
  95 namespace {
  96
  97 struct ModulePassPrinter : public ModulePass {
  98   static char ID;
  99   const PassInfo *PassToPrint;
 100   ModulePassPrinter(const PassInfo *PI) : ModulePass((intptr_t)&ID),
 101                                           PassToPrint(PI) {}
 102
 103   virtual bool runOnModule(Module &M) {
 104     if (!Quiet) {
 105       cout << "Printing analysis '" << PassToPrint->getPassName() << "':\n";
 106       getAnalysisID<Pass>(PassToPrint).print(cout, &M);
 107     }
 108
 109     // Get and print pass...
 110     return false;
 111   }
 112
 113   virtual const char *getPassName() const { return "'Pass' Printer"; }
 114
 115   virtual void getAnalysisUsage(AnalysisUsage &AU) const {
 116     AU.addRequiredID(PassToPrint);
 117     AU.setPreservesAll();
 118   }
 119 };
 120
 121 char ModulePassPrinter::ID = 0;
 122 struct FunctionPassPrinter : public FunctionPass {
 123   const PassInfo *PassToPrint;
 124   static char ID;
 125   FunctionPassPrinter(const PassInfo *PI) : FunctionPass((intptr_t)&ID),
 126                                             PassToPrint(PI) {}
 127
 128   virtual bool runOnFunction(Function &F) {
 129     if (!Quiet) {
 130       cout << "Printing analysis '" << PassToPrint->getPassName()
 131            << "' for function '" << F.getName() << "':\n";
 132     }
 133     // Get and print pass...
 134     getAnalysisID<Pass>(PassToPrint).print(cout, F.getParent());
 135     return false;
 136   }
 137
 138   virtual const char *getPassName() const { return "FunctionPass Printer"; }
 139
 140   virtual void getAnalysisUsage(AnalysisUsage &AU) const {
 141     AU.addRequiredID(PassToPrint);
 142     AU.setPreservesAll();
 143   }
 144 };
 145
 146 char FunctionPassPrinter::ID = 0;
 147 struct BasicBlockPassPrinter : public BasicBlockPass {
 148   const PassInfo *PassToPrint;
 149   static char ID;
 150   BasicBlockPassPrinter(const PassInfo *PI)
 151     : BasicBlockPass((intptr_t)&ID), PassToPrint(PI) {}
 152
 153   virtual bool runOnBasicBlock(BasicBlock &BB) {
 154     if (!Quiet) {
 155       cout << "Printing Analysis info for BasicBlock '" << BB.getName()
 156            << "': Pass " << PassToPrint->getPassName() << ":\n";
 157     }
 158
 159     // Get and print pass...
 160     getAnalysisID<Pass>(PassToPrint).print(cout, BB.getParent()->getParent());
 161     return false;
 162   }
 163
 164   virtual const char *getPassName() const { return "BasicBlockPass Printer"; }
 165
 166   virtual void getAnalysisUsage(AnalysisUsage &AU) const {
 167     AU.addRequiredID(PassToPrint);
 168     AU.setPreservesAll();
 169   }
 170 };
 171
 172 char BasicBlockPassPrinter::ID = 0;
 173 inline void addPass(PassManager &PM, Pass *P) {
 174   // Add the pass to the pass manager...
 175   PM.add(P);
 176
 177   // If we are verifying all of the intermediate steps, add the verifier...
 178   if (VerifyEach) PM.add(createVerifierPass());
 179 }
 180
 181 void AddStandardCompilePasses(PassManager &PM) {
 182   PM.add(createVerifierPass());                  // Verify that input is correct
 183
 184   addPass(PM, createLowerSetJmpPass());          // Lower llvm.setjmp/.longjmp
 185
 186   // If the -strip-debug command line option was specified, do it.
 187   if (StripDebug)
 188     addPass(PM, createStripSymbolsPass(true));
 189
 190   if (DisableOptimizations) return;
 191
 192   addPass(PM, createRaiseAllocationsPass());     // call %malloc -> malloc inst
 193   addPass(PM, createCFGSimplificationPass());    // Clean up disgusting code
 194   addPass(PM, createPromoteMemoryToRegisterPass());// Kill useless allocas
 195   addPass(PM, createGlobalOptimizerPass());      // Optimize out global vars
 196   addPass(PM, createGlobalDCEPass());            // Remove unused fns and globs
 197   addPass(PM, createIPConstantPropagationPass());// IP Constant Propagation
 198   addPass(PM, createDeadArgEliminationPass());   // Dead argument elimination
 199   addPass(PM, createInstructionCombiningPass()); // Clean up after IPCP & DAE
 200   addPass(PM, createCFGSimplificationPass());    // Clean up after IPCP & DAE
 201
 202   addPass(PM, createPruneEHPass());              // Remove dead EH info
 203
 204   if (!DisableInline)
 205     addPass(PM, createFunctionInliningPass());   // Inline small functions
 206   addPass(PM, createArgumentPromotionPass());    // Scalarize uninlined fn args
 207
 208   addPass(PM, createTailDuplicationPass());      // Simplify cfg by copying code
 209   addPass(PM, createInstructionCombiningPass()); // Cleanup for scalarrepl.
 210   addPass(PM, createCFGSimplificationPass());    // Merge & remove BBs
 211   addPass(PM, createScalarReplAggregatesPass()); // Break up aggregate allocas
 212   addPass(PM, createInstructionCombiningPass()); // Combine silly seq's
 213   addPass(PM, createCondPropagationPass());      // Propagate conditionals
 214
 215   addPass(PM, createTailCallEliminationPass());  // Eliminate tail calls
 216   addPass(PM, createCFGSimplificationPass());    // Merge & remove BBs
 217   addPass(PM, createReassociatePass());          // Reassociate expressions
 218   addPass(PM, createLoopRotatePass());
 219   addPass(PM, createLICMPass());                 // Hoist loop invariants
 220   addPass(PM, createLoopUnswitchPass());         // Unswitch loops.
 221   addPass(PM, createInstructionCombiningPass()); // Clean up after LICM/reassoc
 222   addPass(PM, createIndVarSimplifyPass());       // Canonicalize indvars
 223   addPass(PM, createLoopUnrollPass());           // Unroll small loops
 224   addPass(PM, createInstructionCombiningPass()); // Clean up after the unroller
 225   addPass(PM, createLoadValueNumberingPass());   // GVN for load instructions
 226   addPass(PM, createGCSEPass());                 // Remove common subexprs
 227   addPass(PM, createSCCPPass());                 // Constant prop with SCCP
 228
 229   // Run instcombine after redundancy elimination to exploit opportunities
 230   // opened up by them.
 231   addPass(PM, createInstructionCombiningPass());
 232   addPass(PM, createCondPropagationPass());      // Propagate conditionals
 233
 234   addPass(PM, createDeadStoreEliminationPass()); // Delete dead stores
 235   addPass(PM, createAggressiveDCEPass());        // SSA based 'Aggressive DCE'
 236   addPass(PM, createCFGSimplificationPass());    // Merge & remove BBs
 237   addPass(PM, createSimplifyLibCallsPass());     // Library Call Optimizations
 238   addPass(PM, createDeadTypeEliminationPass());  // Eliminate dead types
 239   addPass(PM, createConstantMergePass());        // Merge dup global constants
 240 }
 241
 242 } // anonymous namespace
 243
 244
 245 //===----------------------------------------------------------------------===//
 246 // main for opt
 247 //
 248 int main(int argc, char **argv) {
 249   llvm_shutdown_obj X;  // Call llvm_shutdown() on exit.
 250   try {
 251     cl::ParseCommandLineOptions(argc, argv,
 252       " llvm .bc -> .bc modular optimizer and analysis printer \n");
 253     sys::PrintStackTraceOnErrorSignal();
 254
 255     // Allocate a full target machine description only if necessary.
 256     // FIXME: The choice of target should be controllable on the command line.
 257     std::auto_ptr<TargetMachine> target;
 258
 259     std::string ErrorMessage;
 260
 261     // Load the input module...
 262     std::auto_ptr<Module> M;
 263     if (MemoryBuffer *Buffer
 264           = MemoryBuffer::getFileOrSTDIN(InputFilename, &ErrorMessage)) {
 265       M.reset(ParseBitcodeFile(Buffer, &ErrorMessage));
 266       delete Buffer;
 267     }
 268
 269     if (M.get() == 0) {
 270       cerr << argv[0] << ": ";
 271       if (ErrorMessage.size())
 272         cerr << ErrorMessage << "\n";
 273       else
 274         cerr << "bytecode didn't read correctly.\n";
 275       return 1;
 276     }
 277
 278     // Figure out what stream we are supposed to write to...
 279     // FIXME: cout is not binary!
 280     std::ostream *Out = &std::cout;  // Default to printing to stdout...
 281     if (OutputFilename != "-") {
 282       if (!Force && std::ifstream(OutputFilename.c_str())) {
 283         // If force is not specified, make sure not to overwrite a file!
 284         cerr << argv[0] << ": error opening '" << OutputFilename
 285              << "': file exists!\n"
 286              << "Use -f command line argument to force output\n";
 287         return 1;
 288       }
 289       std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
 290                                    std::ios::binary;
 291       Out = new std::ofstream(OutputFilename.c_str(), io_mode);
 292
 293       if (!Out->good()) {
 294         cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
 295         return 1;
 296       }
 297
 298       // Make sure that the Output file gets unlinked from the disk if we get a
 299       // SIGINT
 300       sys::RemoveFileOnSignal(sys::Path(OutputFilename));
 301     }
 302
 303     // If the output is set to be emitted to standard out, and standard out is a
 304     // console, print out a warning message and refuse to do it.  We don't
 305     // impress anyone by spewing tons of binary goo to a terminal.
 306     if (!Force && !NoOutput && CheckBytecodeOutputToConsole(Out,!Quiet)) {
 307       NoOutput = true;
 308     }
 309
 310     // Create a PassManager to hold and optimize the collection of passes we are
 311     // about to build...
 312     //
 313     PassManager Passes;
 314
 315     // Add an appropriate TargetData instance for this module...
 316     Passes.add(new TargetData(M.get()));
 317
 318     // If -std-compile-opts is given, add in all the standard compilation
 319     // optimizations first. This will handle -strip-debug, -disable-inline,
 320     // and -disable-opt as well.
 321     if (StandardCompileOpts)
 322       AddStandardCompilePasses(Passes);
 323
 324     // otherwise if the -strip-debug command line option was specified, add it.
 325     else if (StripDebug)
 326       addPass(Passes, createStripSymbolsPass(true));
 327
 328     // Create a new optimization pass for each one specified on the command line
 329     for (unsigned i = 0; i < PassList.size(); ++i) {
 330       const PassInfo *PassInf = PassList[i];
 331       Pass *P = 0;
 332       if (PassInf->getNormalCtor())
 333         P = PassInf->getNormalCtor()();
 334       else
 335         cerr << argv[0] << ": cannot create pass: "
 336              << PassInf->getPassName() << "\n";
 337       if (P) {
 338         addPass(Passes, P);
 339
 340         if (AnalyzeOnly) {
 341           if (dynamic_cast<BasicBlockPass*>(P))
 342             Passes.add(new BasicBlockPassPrinter(PassInf));
 343           else if (dynamic_cast<FunctionPass*>(P))
 344             Passes.add(new FunctionPassPrinter(PassInf));
 345           else
 346             Passes.add(new ModulePassPrinter(PassInf));
 347         }
 348       }
 349
 350       if (PrintEachXForm)
 351         Passes.add(new PrintModulePass(&cerr));
 352     }
 353
 354     // Check that the module is well formed on completion of optimization
 355     if (!NoVerify && !VerifyEach)
 356       Passes.add(createVerifierPass());
 357
 358     // Write bytecode out to disk or cout as the last step...
 359     if (!NoOutput && !AnalyzeOnly)
 360       Passes.add(CreateBitcodeWriterPass(*Out));
 361
 362     // Now that we have all of the passes ready, run them.
 363     Passes.run(*M.get());
 364
 365     // Delete the ofstream.
 366     if (Out != &std::cout)
 367       delete Out;
 368     return 0;
 369
 370   } catch (const std::string& msg) {
 371     cerr << argv[0] << ": " << msg << "\n";
 372   } catch (...) {
 373     cerr << argv[0] << ": Unexpected unknown exception occurred.\n";
 374   }
 375   llvm_shutdown();
 376   return 1;
 377 }