1 //===-- llvm-diff.cpp - Module comparator command-line driver ---*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the command-line driver for the difference engine.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "lib/DiffLog.h"
14 #include "lib/DifferenceEngine.h"
15 #include "llvm/ADT/StringRef.h"
16 #include "llvm/IR/LLVMContext.h"
17 #include "llvm/IR/Module.h"
18 #include "llvm/IR/Type.h"
19 #include "llvm/IRReader/IRReader.h"
20 #include "llvm/Support/CommandLine.h"
21 #include "llvm/Support/MemoryBuffer.h"
22 #include "llvm/Support/SourceMgr.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include "llvm/Support/WithColor.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   Name.consume_front("@");
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 cl::OptionCategory DiffCategory("Diff Options");
60 
61 static cl::opt<std::string> LeftFilename(cl::Positional,
62                                          cl::desc("<first file>"), cl::Required,
63                                          cl::cat(DiffCategory));
64 static cl::opt<std::string> RightFilename(cl::Positional,
65                                           cl::desc("<second file>"),
66                                           cl::Required, cl::cat(DiffCategory));
67 static cl::list<std::string> GlobalsToCompare(cl::Positional,
68                                               cl::desc("<globals to compare>"),
69                                               cl::cat(DiffCategory));
70 
71 int main(int argc, char **argv) {
72   cl::HideUnrelatedOptions({&DiffCategory, &getColorCategory()});
73   cl::ParseCommandLineOptions(argc, argv);
74 
75   LLVMContext Context;
76 
77   // Load both modules.  Die if that fails.
78   std::unique_ptr<Module> LModule = readModule(Context, LeftFilename);
79   std::unique_ptr<Module> RModule = readModule(Context, RightFilename);
80   if (!LModule || !RModule) return 1;
81 
82   DiffConsumer Consumer;
83   DifferenceEngine Engine(Consumer);
84 
85   // If any global names were given, just diff those.
86   if (!GlobalsToCompare.empty()) {
87     for (unsigned I = 0, E = GlobalsToCompare.size(); I != E; ++I)
88       diffGlobal(Engine, *LModule, *RModule, GlobalsToCompare[I]);
89 
90   // Otherwise, diff everything in the module.
91   } else {
92     Engine.diff(LModule.get(), RModule.get());
93   }
94 
95   return Consumer.hadDifferences();
96 }
97