tools/llvm-extract/llvm-extract.cpp

   1 //===- llvm-extract.cpp - LLVM function extraction utility ----------------===//
   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 utility changes the input module to only contain a single function,
  11 // which is primarily used for debugging transformations.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/LLVMContext.h"
  16 #include "llvm/Module.h"
  17 #include "llvm/PassManager.h"
  18 #include "llvm/Assembly/PrintModulePass.h"
  19 #include "llvm/Bitcode/ReaderWriter.h"
  20 #include "llvm/Transforms/IPO.h"
  21 #include "llvm/Target/TargetData.h"
  22 #include "llvm/Support/CommandLine.h"
  23 #include "llvm/Support/IRReader.h"
  24 #include "llvm/Support/ManagedStatic.h"
  25 #include "llvm/Support/PrettyStackTrace.h"
  26 #include "llvm/Support/ToolOutputFile.h"
  27 #include "llvm/Support/SystemUtils.h"
  28 #include "llvm/Support/Signals.h"
  29 #include "llvm/ADT/SmallPtrSet.h"
  30 #include <memory>
  31 using namespace llvm;
  32
  33 // InputFilename - The filename to read from.
  34 static cl::opt<std::string>
  35 InputFilename(cl::Positional, cl::desc("<input bitcode file>"),
  36               cl::init("-"), cl::value_desc("filename"));
  37
  38 static cl::opt<std::string>
  39 OutputFilename("o", cl::desc("Specify output filename"),
  40                cl::value_desc("filename"), cl::init("-"));
  41
  42 static cl::opt<bool>
  43 Force("f", cl::desc("Enable binary output on terminals"));
  44
  45 static cl::opt<bool>
  46 DeleteFn("delete", cl::desc("Delete specified Globals from Module"));
  47
  48 // ExtractFuncs - The functions to extract from the module...
  49 static cl::list<std::string>
  50 ExtractFuncs("func", cl::desc("Specify function to extract"),
  51              cl::ZeroOrMore, cl::value_desc("function"));
  52
  53 // ExtractGlobals - The globals to extract from the module...
  54 static cl::list<std::string>
  55 ExtractGlobals("glob", cl::desc("Specify global to extract"),
  56                cl::ZeroOrMore, cl::value_desc("global"));
  57
  58 static cl::opt<bool>
  59 OutputAssembly("S",
  60                cl::desc("Write output as LLVM assembly"), cl::Hidden);
  61
  62 int main(int argc, char **argv) {
  63   // Print a stack trace if we signal out.
  64   sys::PrintStackTraceOnErrorSignal();
  65   PrettyStackTraceProgram X(argc, argv);
  66
  67   LLVMContext &Context = getGlobalContext();
  68   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
  69   cl::ParseCommandLineOptions(argc, argv, "llvm extractor\n");
  70
  71   // Use lazy loading, since we only care about selected global values.
  72   SMDiagnostic Err;
  73   std::auto_ptr<Module> M;
  74   M.reset(getLazyIRFileModule(InputFilename, Err, Context));
  75
  76   if (M.get() == 0) {
  77     Err.Print(argv[0], errs());
  78     return 1;
  79   }
  80
  81   std::vector<GlobalValue *> GVs;
  82
  83   // Figure out which globals we should extract.
  84   for (size_t i = 0, e = ExtractGlobals.size(); i != e; ++i) {
  85     GlobalValue *GV = M.get()->getNamedGlobal(ExtractGlobals[i]);
  86     if (!GV) {
  87       errs() << argv[0] << ": program doesn't contain global named '"
  88              << ExtractGlobals[i] << "'!\n";
  89       return 1;
  90     }
  91     GVs.push_back(GV);
  92   }
  93
  94   // Figure out which functions we should extract.
  95   for (size_t i = 0, e = ExtractFuncs.size(); i != e; ++i) {
  96     GlobalValue *GV = M.get()->getFunction(ExtractFuncs[i]);
  97     if (!GV) {
  98       errs() << argv[0] << ": program doesn't contain function named '"
  99              << ExtractFuncs[i] << "'!\n";
 100       return 1;
 101     }
 102     GVs.push_back(GV);
 103   }
 104
 105   // Materialize requisite global values.
 106   if (!DeleteFn)
 107     for (size_t i = 0, e = GVs.size(); i != e; ++i) {
 108       GlobalValue *GV = GVs[i];
 109       if (GV->isMaterializable()) {
 110         std::string ErrInfo;
 111         if (GV->Materialize(&ErrInfo)) {
 112           errs() << argv[0] << ": error reading input: " << ErrInfo << "\n";
 113           return 1;
 114         }
 115       }
 116     }
 117   else {
 118     // Deleting. Materialize every GV that's *not* in GVs.
 119     SmallPtrSet<GlobalValue *, 8> GVSet(GVs.begin(), GVs.end());
 120     for (Module::global_iterator I = M->global_begin(), E = M->global_end();
 121          I != E; ++I) {
 122       GlobalVariable *G = I;
 123       if (!GVSet.count(G) && G->isMaterializable()) {
 124         std::string ErrInfo;
 125         if (G->Materialize(&ErrInfo)) {
 126           errs() << argv[0] << ": error reading input: " << ErrInfo << "\n";
 127           return 1;
 128         }
 129       }
 130     }
 131     for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) {
 132       Function *F = I;
 133       if (!GVSet.count(F) && F->isMaterializable()) {
 134         std::string ErrInfo;
 135         if (F->Materialize(&ErrInfo)) {
 136           errs() << argv[0] << ": error reading input: " << ErrInfo << "\n";
 137           return 1;
 138         }
 139       }
 140     }
 141   }
 142
 143   // In addition to deleting all other functions, we also want to spiff it
 144   // up a little bit.  Do this now.
 145   PassManager Passes;
 146   Passes.add(new TargetData(M.get())); // Use correct TargetData
 147
 148   Passes.add(createGVExtractionPass(GVs, DeleteFn));
 149   if (!DeleteFn)
 150     Passes.add(createGlobalDCEPass());           // Delete unreachable globals
 151   Passes.add(createStripDeadDebugInfoPass());    // Remove dead debug info
 152   Passes.add(createDeadTypeEliminationPass());   // Remove dead types...
 153   Passes.add(createStripDeadPrototypesPass());   // Remove dead func decls
 154
 155   std::string ErrorInfo;
 156   tool_output_file Out(OutputFilename.c_str(), ErrorInfo,
 157                        raw_fd_ostream::F_Binary);
 158   if (!ErrorInfo.empty()) {
 159     errs() << ErrorInfo << '\n';
 160     return 1;
 161   }
 162
 163   if (OutputAssembly)
 164     Passes.add(createPrintModulePass(&Out.os()));
 165   else if (Force || !CheckBitcodeOutputToConsole(Out.os(), true))
 166     Passes.add(createBitcodeWriterPass(Out.os()));
 167
 168   Passes.run(*M.get());
 169
 170   // Declare success.
 171   Out.keep();
 172
 173   return 0;
 174 }