Esempio n. 1
0
/// Optimize - Perform link time optimizations. This will run the scalar
/// optimizations, any loaded plugin-optimization modules, and then the
/// inter-procedural optimizations if applicable.
void Optimize(Module *M, const std::string &EntryPoint) {

  // Instantiate the pass manager to organize the passes.
  PassManager Passes;

  // If we're verifying, start off with a verification pass.
  if (VerifyEach)
    Passes.add(createVerifierPass());

#if LLVM_VERSION_CODE <= LLVM_VERSION(3, 1)
  // Add an appropriate TargetData instance for this module...
  addPass(Passes, new TargetData(M));
#elif LLVM_VERSION_CODE < LLVM_VERSION(3, 5)
  // Add an appropriate DataLayout instance for this module...
  addPass(Passes, new DataLayout(M));
#else
  // Add an appropriate DataLayout instance for this module...
  addPass(Passes, new DataLayoutPass(M));
#endif

  // DWD - Run the opt standard pass list as well.
  AddStandardCompilePasses(Passes);

  if (!DisableOptimizations) {
    // Now that composite has been compiled, scan through the module, looking
    // for a main function.  If main is defined, mark all other functions
    // internal.
    if (!DisableInternalize) {
#if LLVM_VERSION_CODE >= LLVM_VERSION(3, 2)
      ModulePass *pass = createInternalizePass(
          std::vector<const char *>(1, EntryPoint.c_str()));
#else
      ModulePass *pass = createInternalizePass(true);
#endif
      addPass(Passes, pass);
    }

    // Propagate constants at call sites into the functions they call.  This
    // opens opportunities for globalopt (and inlining) by substituting function
    // pointers passed as arguments to direct uses of functions.  
    addPass(Passes, createIPSCCPPass());

    // Now that we internalized some globals, see if we can hack on them!
    addPass(Passes, createGlobalOptimizerPass());

    // Linking modules together can lead to duplicated global constants, only
    // keep one copy of each constant...
    addPass(Passes, createConstantMergePass());

    // Remove unused arguments from functions...
    addPass(Passes, createDeadArgEliminationPass());

    // Reduce the code after globalopt and ipsccp.  Both can open up significant
    // simplification opportunities, and both can propagate functions through
    // function pointers.  When this happens, we often have to resolve varargs
    // calls, etc, so let instcombine do this.
    addPass(Passes, createInstructionCombiningPass());

    if (!DisableInline)
      addPass(Passes, createFunctionInliningPass()); // Inline small functions

    addPass(Passes, createPruneEHPass());            // Remove dead EH info
    addPass(Passes, createGlobalOptimizerPass());    // Optimize globals again.
    addPass(Passes, createGlobalDCEPass());          // Remove dead functions

    // If we didn't decide to inline a function, check to see if we can
    // transform it to pass arguments by value instead of by reference.
    addPass(Passes, createArgumentPromotionPass());

    // The IPO passes may leave cruft around.  Clean up after them.
    addPass(Passes, createInstructionCombiningPass());
    addPass(Passes, createJumpThreadingPass());        // Thread jumps.
    addPass(Passes, createScalarReplAggregatesPass()); // Break up allocas

    // Run a few AA driven optimizations here and now, to cleanup the code.
    addPass(Passes, createFunctionAttrsPass());      // Add nocapture
    addPass(Passes, createGlobalsModRefPass());      // IP alias analysis

    addPass(Passes, createLICMPass());               // Hoist loop invariants
    addPass(Passes, createGVNPass());                // Remove redundancies
    addPass(Passes, createMemCpyOptPass());          // Remove dead memcpy's
    addPass(Passes, createDeadStoreEliminationPass()); // Nuke dead stores

    // Cleanup and simplify the code after the scalar optimizations.
    addPass(Passes, createInstructionCombiningPass());

    addPass(Passes, createJumpThreadingPass());        // Thread jumps.
    addPass(Passes, createPromoteMemoryToRegisterPass()); // Cleanup jumpthread.
    
    // Delete basic blocks, which optimization passes may have killed...
    addPass(Passes, createCFGSimplificationPass());

    // Now that we have optimized the program, discard unreachable functions...
    addPass(Passes, createGlobalDCEPass());
  }

  // If the -s or -S command line options were specified, strip the symbols out
  // of the resulting program to make it smaller.  -s and -S are GNU ld options
  // that we are supporting; they alias -strip-all and -strip-debug.
  if (Strip || StripDebug)
    addPass(Passes, createStripSymbolsPass(StripDebug && !Strip));

#if 0
  // Create a new optimization pass for each one specified on the command line
  std::auto_ptr<TargetMachine> target;
  for (unsigned i = 0; i < OptimizationList.size(); ++i) {
    const PassInfo *Opt = OptimizationList[i];
    if (Opt->getNormalCtor())
      addPass(Passes, Opt->getNormalCtor()());
    else
      llvm::errs() << "llvm-ld: cannot create pass: "******"\n";
  }
#endif

  // The user's passes may leave cruft around. Clean up after them them but
  // only if we haven't got DisableOptimizations set
  if (!DisableOptimizations) {
    addPass(Passes, createInstructionCombiningPass());
    addPass(Passes, createCFGSimplificationPass());
    addPass(Passes, createAggressiveDCEPass());
    addPass(Passes, createGlobalDCEPass());
  }

  // Make sure everything is still good.
  if (!DontVerify)
    Passes.add(createVerifierPass());

  // Run our queue of passes all at once now, efficiently.
  Passes.run(*M);
}
Esempio n. 2
0
static void AddStandardCompilePasses(PassManager &PM) {
  PM.add(createVerifierPass());                  // Verify that input is correct

#if LLVM_VERSION_CODE < LLVM_VERSION(3, 0)
  addPass(PM, createLowerSetJmpPass());          // Lower llvm.setjmp/.longjmp
#endif

  // If the -strip-debug command line option was specified, do it.
  if (StripDebug)
    addPass(PM, createStripSymbolsPass(true));

  if (DisableOptimizations) return;

  addPass(PM, createCFGSimplificationPass());    // Clean up disgusting code
  addPass(PM, createPromoteMemoryToRegisterPass());// Kill useless allocas
  addPass(PM, createGlobalOptimizerPass());      // Optimize out global vars
  addPass(PM, createGlobalDCEPass());            // Remove unused fns and globs
  addPass(PM, createIPConstantPropagationPass());// IP Constant Propagation
  addPass(PM, createDeadArgEliminationPass());   // Dead argument elimination
  addPass(PM, createInstructionCombiningPass()); // Clean up after IPCP & DAE
  addPass(PM, createCFGSimplificationPass());    // Clean up after IPCP & DAE

  addPass(PM, createPruneEHPass());              // Remove dead EH info
  addPass(PM, createFunctionAttrsPass());        // Deduce function attrs

  if (!DisableInline)
    addPass(PM, createFunctionInliningPass());   // Inline small functions
  addPass(PM, createArgumentPromotionPass());    // Scalarize uninlined fn args

#if LLVM_VERSION_CODE < LLVM_VERSION(3, 4)
  addPass(PM, createSimplifyLibCallsPass());     // Library Call Optimizations
#endif
  addPass(PM, createInstructionCombiningPass()); // Cleanup for scalarrepl.
  addPass(PM, createJumpThreadingPass());        // Thread jumps.
  addPass(PM, createCFGSimplificationPass());    // Merge & remove BBs
  addPass(PM, createScalarReplAggregatesPass()); // Break up aggregate allocas
  addPass(PM, createInstructionCombiningPass()); // Combine silly seq's

  addPass(PM, createTailCallEliminationPass());  // Eliminate tail calls
  addPass(PM, createCFGSimplificationPass());    // Merge & remove BBs
  addPass(PM, createReassociatePass());          // Reassociate expressions
  addPass(PM, createLoopRotatePass());
  addPass(PM, createLICMPass());                 // Hoist loop invariants
  addPass(PM, createLoopUnswitchPass());         // Unswitch loops.
  // FIXME : Removing instcombine causes nestedloop regression.
  addPass(PM, createInstructionCombiningPass());
  addPass(PM, createIndVarSimplifyPass());       // Canonicalize indvars
  addPass(PM, createLoopDeletionPass());         // Delete dead loops
  addPass(PM, createLoopUnrollPass());           // Unroll small loops
  addPass(PM, createInstructionCombiningPass()); // Clean up after the unroller
  addPass(PM, createGVNPass());                  // Remove redundancies
  addPass(PM, createMemCpyOptPass());            // Remove memcpy / form memset
  addPass(PM, createSCCPPass());                 // Constant prop with SCCP

  // Run instcombine after redundancy elimination to exploit opportunities
  // opened up by them.
  addPass(PM, createInstructionCombiningPass());

  addPass(PM, createDeadStoreEliminationPass()); // Delete dead stores
  addPass(PM, createAggressiveDCEPass());        // Delete dead instructions
  addPass(PM, createCFGSimplificationPass());    // Merge & remove BBs
  addPass(PM, createStripDeadPrototypesPass());  // Get rid of dead prototypes
#if LLVM_VERSION_CODE < LLVM_VERSION(3, 0)
  addPass(PM, createDeadTypeEliminationPass());  // Eliminate dead types
#endif
  addPass(PM, createConstantMergePass());        // Merge dup global constants
}
static void createOptimizationPasses() {
  // Create and set up the per-function pass manager.
  // FIXME: Move the code generator to be function-at-a-time.
  PerFunctionPasses =
    new FunctionPassManager(new ExistingModuleProvider(TheModule));
  PerFunctionPasses->add(new TargetData(*TheTarget->getTargetData()));

  // In -O0 if checking is disabled, we don't even have per-function passes.
  bool HasPerFunctionPasses = false;
#ifdef ENABLE_CHECKING
  PerFunctionPasses->add(createVerifierPass());
  HasPerFunctionPasses = true;
#endif

  if (optimize > 0 && !DisableLLVMOptimizations) {
    HasPerFunctionPasses = true;
    PerFunctionPasses->add(createCFGSimplificationPass());
    if (optimize == 1)
      PerFunctionPasses->add(createPromoteMemoryToRegisterPass());
    else
      PerFunctionPasses->add(createScalarReplAggregatesPass());
    PerFunctionPasses->add(createInstructionCombiningPass());
    //    PerFunctionPasses->add(createCFGSimplificationPass());
  }

  // FIXME: AT -O0/O1, we should stream out functions at a time.
  PerModulePasses = new PassManager();
  PerModulePasses->add(new TargetData(*TheTarget->getTargetData()));
  bool HasPerModulePasses = false;

  if (optimize > 0 && !DisableLLVMOptimizations) {
    HasPerModulePasses = true;
    PassManager *PM = PerModulePasses;
    if (flag_unit_at_a_time)
      PM->add(createRaiseAllocationsPass());      // call %malloc -> malloc inst
    PM->add(createCFGSimplificationPass());       // Clean up disgusting code
    PM->add(createPromoteMemoryToRegisterPass()); // Kill useless allocas
    if (flag_unit_at_a_time) {
      PM->add(createGlobalOptimizerPass());       // Optimize out global vars
      PM->add(createGlobalDCEPass());             // Remove unused fns and globs
      PM->add(createIPConstantPropagationPass()); // IP Constant Propagation
      PM->add(createDeadArgEliminationPass());    // Dead argument elimination
    }
    PM->add(createInstructionCombiningPass());    // Clean up after IPCP & DAE
    // DISABLE PREDSIMPLIFY UNTIL PR967 is fixed.
    //PM->add(createPredicateSimplifierPass());   // Canonicalize registers
    PM->add(createCFGSimplificationPass());       // Clean up after IPCP & DAE
    if (flag_unit_at_a_time)
      PM->add(createPruneEHPass());               // Remove dead EH info

    if (optimize > 1) {
      if (flag_inline_trees > 1)                // respect -fno-inline-functions
        PM->add(createFunctionInliningPass());  // Inline small functions
      if (flag_unit_at_a_time && !lang_hooks.flag_no_builtin())
        PM->add(createSimplifyLibCallsPass());  // Library Call Optimizations

      if (optimize > 2)
    	PM->add(createArgumentPromotionPass()); // Scalarize uninlined fn args
    }
    
    PM->add(createTailDuplicationPass());       // Simplify cfg by copying code
    PM->add(createInstructionCombiningPass());  // Cleanup for scalarrepl.
    PM->add(createCFGSimplificationPass());     // Merge & remove BBs
    PM->add(createScalarReplAggregatesPass());  // Break up aggregate allocas
    PM->add(createInstructionCombiningPass());  // Combine silly seq's
    PM->add(createCondPropagationPass());       // Propagate conditionals
    PM->add(createTailCallEliminationPass());   // Eliminate tail calls
    PM->add(createCFGSimplificationPass());     // Merge & remove BBs
    PM->add(createReassociatePass());           // Reassociate expressions
    PM->add(createLoopRotatePass());            // Rotate Loop
    PM->add(createLICMPass());                  // Hoist loop invariants
    PM->add(createLoopUnswitchPass(optimize_size ? true : false));
    PM->add(createInstructionCombiningPass());  // Clean up after LICM/reassoc
    PM->add(createIndVarSimplifyPass());        // Canonicalize indvars
    if (flag_unroll_loops)
      PM->add(createLoopUnrollPass());          // Unroll small loops
    PM->add(createInstructionCombiningPass());  // Clean up after the unroller
    PM->add(createLoadValueNumberingPass());    // GVN for load instructions
    PM->add(createGCSEPass());                  // Remove common subexprs
    PM->add(createSCCPPass());                  // Constant prop with SCCP
    
    // Run instcombine after redundancy elimination to exploit opportunities
    // opened up by them.
    PM->add(createInstructionCombiningPass());
    PM->add(createCondPropagationPass());       // Propagate conditionals
    PM->add(createDeadStoreEliminationPass());  // Delete dead stores
    PM->add(createAggressiveDCEPass());         // SSA based 'Aggressive DCE'
    PM->add(createCFGSimplificationPass());     // Merge & remove BBs
    
    if (optimize > 1 && flag_unit_at_a_time)
      PM->add(createConstantMergePass());       // Merge dup global constants 
    PM->add(createStripDeadPrototypesPass());   // Get rid of dead prototypes
  }
  
  if (emit_llvm_bc) {
    // Emit an LLVM .bc file to the output.  This is used when passed
    // -emit-llvm -c to the GCC driver.
    PerModulePasses->add(CreateBitcodeWriterPass(*AsmOutStream));

    // Disable emission of .ident into the output file... which is completely
    // wrong for llvm/.bc emission cases.
    flag_no_ident = 1;
    HasPerModulePasses = true;
  } else if (emit_llvm) {
    // Emit an LLVM .ll file to the output.  This is used when passed 
    // -emit-llvm -S to the GCC driver.
    PerModulePasses->add(new PrintModulePass(AsmOutFile));
    
    // Disable emission of .ident into the output file... which is completely
    // wrong for llvm/.bc emission cases.
    flag_no_ident = 1;
    HasPerModulePasses = true;
  } else {
    FunctionPassManager *PM;
    
    // If there are passes we have to run on the entire module, we do codegen
    // as a separate "pass" after that happens.
    // FIXME: This is disabled right now until bugs can be worked out.  Reenable
    // this for fast -O0 compiles!
    if (HasPerModulePasses || 1) {
      CodeGenPasses = PM =
        new FunctionPassManager(new ExistingModuleProvider(TheModule));
      PM->add(new TargetData(*TheTarget->getTargetData()));
    } else {
      // If there are no module-level passes that have to be run, we codegen as
      // each function is parsed.
      PM = PerFunctionPasses;
      HasPerFunctionPasses = true;
    }

    // Normal mode, emit a .s file by running the code generator.
    switch (TheTarget->addPassesToEmitFile(*PM, *AsmOutStream,
                                           TargetMachine::AssemblyFile,
                                           /*FAST*/optimize == 0)) {
    default:
    case FileModel::Error:
      cerr << "Error interfacing to target machine!\n";
      exit(1);
    case FileModel::AsmFile:
      break;
    }

    if (TheTarget->addPassesToEmitFileFinish(*PM, 0, /*Fast*/optimize == 0)) {
      cerr << "Error interfacing to target machine!\n";
      exit(1);
    }
  }
  
  if (HasPerFunctionPasses) {
    PerFunctionPasses->doInitialization();
  } else {
    delete PerFunctionPasses;
    PerFunctionPasses = 0;
  }
  if (!HasPerModulePasses) {
    delete PerModulePasses;
    PerModulePasses = 0;
  }
}