tools/llvm-ld/Optimize.cpp

   1 //===- Optimize.cpp - Optimize a complete program -------------------------===//
   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 all optimization of the linked module for llvm-ld.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Module.h"
  15 #include "llvm/PassManager.h"
  16 #include "llvm/Support/CommandLine.h"
  17 #include "llvm/Support/StandardPasses.h"
  18 #include "llvm/Support/raw_ostream.h"
  19 #include "llvm/Support/DynamicLibrary.h"
  20 #include "llvm/Target/TargetData.h"
  21 #include "llvm/Target/TargetMachine.h"
  22 #include "llvm/Support/PassNameParser.h"
  23 #include "llvm/Support/PluginLoader.h"
  24 using namespace llvm;
  25
  26 // Pass Name Options as generated by the PassNameParser
  27 static cl::list<const PassInfo*, bool, PassNameParser>
  28   OptimizationList(cl::desc("Optimizations available:"));
  29
  30 //Don't verify at the end
  31 static cl::opt<bool> DontVerify("disable-verify", cl::ReallyHidden);
  32
  33 static cl::opt<bool> DisableInline("disable-inlining",
  34   cl::desc("Do not run the inliner pass"));
  35
  36 static cl::opt<bool>
  37 DisableOptimizations("disable-opt",
  38   cl::desc("Do not run any optimization passes"));
  39
  40 static cl::opt<bool> DisableInternalize("disable-internalize",
  41   cl::desc("Do not mark all symbols as internal"));
  42
  43 static cl::opt<bool> VerifyEach("verify-each",
  44  cl::desc("Verify intermediate results of all passes"));
  45
  46 static cl::alias ExportDynamic("export-dynamic",
  47   cl::aliasopt(DisableInternalize),
  48   cl::desc("Alias for -disable-internalize"));
  49
  50 static cl::opt<bool> Strip("strip-all",
  51   cl::desc("Strip all symbol info from executable"));
  52
  53 static cl::alias A0("s", cl::desc("Alias for --strip-all"),
  54   cl::aliasopt(Strip));
  55
  56 static cl::opt<bool> StripDebug("strip-debug",
  57   cl::desc("Strip debugger symbol info from executable"));
  58
  59 static cl::alias A1("S", cl::desc("Alias for --strip-debug"),
  60   cl::aliasopt(StripDebug));
  61
  62 // A utility function that adds a pass to the pass manager but will also add
  63 // a verifier pass after if we're supposed to verify.
  64 static inline void addPass(PassManager &PM, Pass *P) {
  65   // Add the pass to the pass manager...
  66   PM.add(P);
  67
  68   // If we are verifying all of the intermediate steps, add the verifier...
  69   if (VerifyEach)
  70     PM.add(createVerifierPass());
  71 }
  72
  73 namespace llvm {
  74
  75 /// Optimize - Perform link time optimizations. This will run the scalar
  76 /// optimizations, any loaded plugin-optimization modules, and then the
  77 /// inter-procedural optimizations if applicable.
  78 void Optimize(Module* M) {
  79
  80   // Instantiate the pass manager to organize the passes.
  81   PassManager Passes;
  82
  83   // If we're verifying, start off with a verification pass.
  84   if (VerifyEach)
  85     Passes.add(createVerifierPass());
  86
  87   // Add an appropriate TargetData instance for this module...
  88   addPass(Passes, new TargetData(M));
  89
  90   if (!DisableOptimizations)
  91     createStandardLTOPasses(&Passes, !DisableInternalize, !DisableInline,
  92                             VerifyEach);
  93
  94   // If the -s or -S command line options were specified, strip the symbols out
  95   // of the resulting program to make it smaller.  -s and -S are GNU ld options
  96   // that we are supporting; they alias -strip-all and -strip-debug.
  97   if (Strip || StripDebug)
  98     addPass(Passes, createStripSymbolsPass(StripDebug && !Strip));
  99
 100   // Create a new optimization pass for each one specified on the command line
 101   std::auto_ptr<TargetMachine> target;
 102   for (unsigned i = 0; i < OptimizationList.size(); ++i) {
 103     const PassInfo *Opt = OptimizationList[i];
 104     if (Opt->getNormalCtor())
 105       addPass(Passes, Opt->getNormalCtor()());
 106     else
 107       errs() << "llvm-ld: cannot create pass: " << Opt->getPassName()
 108              << "\n";
 109   }
 110
 111   // The user's passes may leave cruft around. Clean up after them them but
 112   // only if we haven't got DisableOptimizations set
 113   if (!DisableOptimizations) {
 114     addPass(Passes, createInstructionCombiningPass());
 115     addPass(Passes, createCFGSimplificationPass());
 116     addPass(Passes, createAggressiveDCEPass());
 117     addPass(Passes, createGlobalDCEPass());
 118   }
 119
 120   // Make sure everything is still good.
 121   if (!DontVerify)
 122     Passes.add(createVerifierPass());
 123
 124   // Run our queue of passes all at once now, efficiently.
 125   Passes.run(*M);
 126 }
 127
 128 }