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      1 //===-- llvm-diff.cpp - Module comparator command-line driver ---*- C++ -*-===//
      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 defines the command-line driver for the difference engine.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "DiffLog.h"
     15 #include "DifferenceEngine.h"
     16 #include "llvm/ADT/StringRef.h"
     17 #include "llvm/IR/LLVMContext.h"
     18 #include "llvm/IR/Module.h"
     19 #include "llvm/IR/Type.h"
     20 #include "llvm/IRReader/IRReader.h"
     21 #include "llvm/Support/CommandLine.h"
     22 #include "llvm/Support/MemoryBuffer.h"
     23 #include "llvm/Support/SourceMgr.h"
     24 #include "llvm/Support/raw_ostream.h"
     25 #include <string>
     26 #include <utility>
     27 
     28 
     29 using namespace llvm;
     30 
     31 /// Reads a module from a file.  On error, messages are written to stderr
     32 /// and null is returned.
     33 static std::unique_ptr<Module> readModule(LLVMContext &Context,
     34                                           StringRef Name) {
     35   SMDiagnostic Diag;
     36   std::unique_ptr<Module> M = parseIRFile(Name, Diag, Context);
     37   if (!M)
     38     Diag.print("llvm-diff", errs());
     39   return M;
     40 }
     41 
     42 static void diffGlobal(DifferenceEngine &Engine, Module &L, Module &R,
     43                        StringRef Name) {
     44   // Drop leading sigils from the global name.
     45   if (Name.startswith("@")) Name = Name.substr(1);
     46 
     47   Function *LFn = L.getFunction(Name);
     48   Function *RFn = R.getFunction(Name);
     49   if (LFn && RFn)
     50     Engine.diff(LFn, RFn);
     51   else if (!LFn && !RFn)
     52     errs() << "No function named @" << Name << " in either module\n";
     53   else if (!LFn)
     54     errs() << "No function named @" << Name << " in left module\n";
     55   else
     56     errs() << "No function named @" << Name << " in right module\n";
     57 }
     58 
     59 static cl::opt<std::string> LeftFilename(cl::Positional,
     60                                          cl::desc("<first file>"),
     61                                          cl::Required);
     62 static cl::opt<std::string> RightFilename(cl::Positional,
     63                                           cl::desc("<second file>"),
     64                                           cl::Required);
     65 static cl::list<std::string> GlobalsToCompare(cl::Positional,
     66                                               cl::desc("<globals to compare>"));
     67 
     68 int main(int argc, char **argv) {
     69   cl::ParseCommandLineOptions(argc, argv);
     70 
     71   LLVMContext Context;
     72 
     73   // Load both modules.  Die if that fails.
     74   std::unique_ptr<Module> LModule = readModule(Context, LeftFilename);
     75   std::unique_ptr<Module> RModule = readModule(Context, RightFilename);
     76   if (!LModule || !RModule) return 1;
     77 
     78   DiffConsumer Consumer;
     79   DifferenceEngine Engine(Consumer);
     80 
     81   // If any global names were given, just diff those.
     82   if (!GlobalsToCompare.empty()) {
     83     for (unsigned I = 0, E = GlobalsToCompare.size(); I != E; ++I)
     84       diffGlobal(Engine, *LModule, *RModule, GlobalsToCompare[I]);
     85 
     86   // Otherwise, diff everything in the module.
     87   } else {
     88     Engine.diff(LModule.get(), RModule.get());
     89   }
     90 
     91   return Consumer.hadDifferences();
     92 }
     93