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