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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.
readModule(LLVMContext & Context,StringRef Name)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 
diffGlobal(DifferenceEngine & Engine,Module & L,Module & R,StringRef Name)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 
main(int argc,char ** argv)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