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