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/Analysis/Passes.h"
  17 #include "llvm/Analysis/LoopPass.h"
  18 #include "llvm/Analysis/Verifier.h"
  19 #include "llvm/Support/CommandLine.h"
  20 #include "llvm/Support/StandardPasses.h"
  21 #include "llvm/Support/raw_ostream.h"
  22 #include "llvm/System/DynamicLibrary.h"
  23 #include "llvm/Target/TargetData.h"
  24 #include "llvm/Target/TargetMachine.h"
  25 #include "llvm/Transforms/IPO.h"
  26 #include "llvm/Transforms/Scalar.h"
  27 #include "llvm/Support/PassNameParser.h"
  28 #include "llvm/Support/PluginLoader.h"
  29 using namespace llvm;
  30
  31 // Pass Name Options as generated by the PassNameParser
  32 static cl::list<const PassInfo*, bool, PassNameParser>
  33   OptimizationList(cl::desc("Optimizations available:"));
  34
  35 //Don't verify at the end
  36 static cl::opt<bool> DontVerify("disable-verify", cl::ReallyHidden);
  37
  38 static cl::opt<bool> DisableInline("disable-inlining",
  39   cl::desc("Do not run the inliner pass"));
  40
  41 static cl::opt<bool>
  42 DisableOptimizations("disable-opt",
  43   cl::desc("Do not run any optimization passes"));
  44
  45 static cl::opt<bool> DisableInternalize("disable-internalize",
  46   cl::desc("Do not mark all symbols as internal"));
  47
  48 static cl::opt<bool> VerifyEach("verify-each",
  49  cl::desc("Verify intermediate results of all passes"));
  50
  51 static cl::alias ExportDynamic("export-dynamic",
  52   cl::aliasopt(DisableInternalize),
  53   cl::desc("Alias for -disable-internalize"));
  54
  55 static cl::opt<bool> Strip("strip-all",
  56   cl::desc("Strip all symbol info from executable"));
  57
  58 static cl::alias A0("s", cl::desc("Alias for --strip-all"),
  59   cl::aliasopt(Strip));
  60
  61 static cl::opt<bool> StripDebug("strip-debug",
  62   cl::desc("Strip debugger symbol info from executable"));
  63
  64 static cl::alias A1("S", cl::desc("Alias for --strip-debug"),
  65   cl::aliasopt(StripDebug));
  66
  67 // A utility function that adds a pass to the pass manager but will also add
  68 // a verifier pass after if we're supposed to verify.
  69 static inline void addPass(PassManager &PM, Pass *P) {
  70   // Add the pass to the pass manager...
  71   PM.add(P);
  72
  73   // If we are verifying all of the intermediate steps, add the verifier...
  74   if (VerifyEach)
  75     PM.add(createVerifierPass());
  76 }
  77
  78 namespace llvm {
  79
  80 /// Optimize - Perform link time optimizations. This will run the scalar
  81 /// optimizations, any loaded plugin-optimization modules, and then the
  82 /// inter-procedural optimizations if applicable.
  83 void Optimize(Module* M) {
  84
  85   // Instantiate the pass manager to organize the passes.
  86   PassManager Passes;
  87
  88   // If we're verifying, start off with a verification pass.
  89   if (VerifyEach)
  90     Passes.add(createVerifierPass());
  91
  92   // Add an appropriate TargetData instance for this module...
  93   addPass(Passes, new TargetData(M));
  94
  95   if (!DisableOptimizations)
  96     createStandardLTOPasses(&Passes, !DisableInternalize, !DisableInline,
  97                             VerifyEach);
  98
  99   // If the -s or -S command line options were specified, strip the symbols out
 100   // of the resulting program to make it smaller.  -s and -S are GNU ld options
 101   // that we are supporting; they alias -strip-all and -strip-debug.
 102   if (Strip || StripDebug)
 103     addPass(Passes, createStripSymbolsPass(StripDebug && !Strip));
 104
 105   // Create a new optimization pass for each one specified on the command line
 106   std::auto_ptr<TargetMachine> target;
 107   for (unsigned i = 0; i < OptimizationList.size(); ++i) {
 108     const PassInfo *Opt = OptimizationList[i];
 109     if (Opt->getNormalCtor())
 110       addPass(Passes, Opt->getNormalCtor()());
 111     else
 112       errs() << "llvm-ld: cannot create pass: " << Opt->getPassName()
 113              << "\n";
 114   }
 115
 116   // The user's passes may leave cruft around. Clean up after them them but
 117   // only if we haven't got DisableOptimizations set
 118   if (!DisableOptimizations) {
 119     addPass(Passes, createInstructionCombiningPass());
 120     addPass(Passes, createCFGSimplificationPass());
 121     addPass(Passes, createAggressiveDCEPass());
 122     addPass(Passes, createGlobalDCEPass());
 123   }
 124
 125   // Make sure everything is still good.
 126   if (!DontVerify)
 127     Passes.add(createVerifierPass());
 128
 129   // Run our queue of passes all at once now, efficiently.
 130   Passes.run(*M);
 131 }
 132
 133 }