1/*
2 * Copyright 2013, The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "llvm/Bitcode/ReaderWriter.h"
18#include "llvm/IR/LLVMContext.h"
19#include "llvm/IR/Module.h"
20#include "llvm/IR/Verifier.h"
21#include "llvm/IRReader/IRReader.h"
22#include "llvm/Pass.h"
23#include "llvm/PassManager.h"
24#include "llvm/Support/CommandLine.h"
25#include "llvm/Support/FileSystem.h"
26#include "llvm/Support/ManagedStatic.h"
27#include "llvm/Support/PrettyStackTrace.h"
28#include "llvm/Support/Signals.h"
29#include "llvm/Support/SourceMgr.h"
30#include "llvm/Support/SystemUtils.h"
31#include "llvm/Support/ToolOutputFile.h"
32using namespace llvm;
33
34static cl::list<std::string>
35InputFilenames(cl::Positional,
36               cl::desc("<input bitcode files>"));
37
38static cl::opt<std::string>
39OutputFilename("o", cl::desc("Override output filename"), cl::init("-"),
40               cl::value_desc("filename"));
41
42static cl::opt<bool>
43OutputAssembly("S",
44               cl::desc("Write output as LLVM assembly"), cl::Hidden);
45
46namespace {
47  class StripAttributes : public ModulePass {
48  public:
49    static char ID;
50
51    StripAttributes() : ModulePass(ID) {
52    }
53
54    bool runOnFunction(Function &F) {
55      // Remove any target-cpu and/or target-features attributes from each
56      // Function or Function declaration.
57      if (F.hasFnAttribute("target-cpu") ||
58          F.hasFnAttribute("target-features")) {
59
60        AttrBuilder B;
61        B.addAttribute("target-cpu").addAttribute("target-features");
62        AttributeSet ToStrip = AttributeSet::get(F.getContext(),
63            AttributeSet::FunctionIndex, B);
64        F.removeAttributes(AttributeSet::FunctionIndex, ToStrip);
65        return true;
66      }
67      return false;
68    }
69
70    // We have to use a ModulePass, since a FunctionPass only gets run on
71    // defined Functions (and not declared Functions).
72    virtual bool runOnModule(Module &M) {
73      bool Changed = false;
74      for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
75        Changed |= runOnFunction(*I);
76      }
77      return Changed;
78    }
79  };
80
81  llvm::ModulePass * createStripAttributePass() {
82    return new StripAttributes();
83  }
84}
85
86
87char StripAttributes::ID = 0;
88static RegisterPass<StripAttributes> RPSA("StripAttributes",
89    "Strip Function Attributes Pass");
90
91
92static inline std::unique_ptr<Module> LoadFile(const char *argv0,
93                                               const std::string &FN,
94                                               LLVMContext& Context) {
95  SMDiagnostic Err;
96  Module* Result = ParseIRFile(FN, Err, Context);
97  if (Result) {
98    return std::unique_ptr<Module>(Result);   // Load successful!
99  }
100
101  Err.print(argv0, errs());
102  return std::unique_ptr<Module>();
103}
104
105
106int main(int argc, char **argv) {
107  // Print a stack trace if we signal out.
108  sys::PrintStackTraceOnErrorSignal();
109  PrettyStackTraceProgram X(argc, argv);
110
111  LLVMContext &Context = getGlobalContext();
112  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
113  cl::ParseCommandLineOptions(argc, argv, "strip function attribute pass\n");
114
115  std::string ErrorMessage;
116
117  std::unique_ptr<Module> M(LoadFile(argv[0], InputFilenames[0], Context));
118  if (M.get() == 0) {
119    errs() << argv[0] << ": error loading file '"
120           << InputFilenames[0] << "'\n";
121    return 1;
122  }
123
124  // Perform the actual function attribute stripping.
125  PassManager PM;
126  PM.add(createStripAttributePass());
127  PM.run(*M.get());
128
129  std::string ErrorInfo;
130  tool_output_file Out(OutputFilename.c_str(), ErrorInfo,
131                       sys::fs::F_None);
132  if (!ErrorInfo.empty()) {
133    errs() << ErrorInfo << '\n';
134    return 1;
135  }
136
137  if (verifyModule(*M)) {
138    errs() << argv[0] << ": stripped module is broken!\n";
139    return 1;
140  }
141
142  if (OutputAssembly) {
143    Out.os() << *M;
144  } else if (!CheckBitcodeOutputToConsole(Out.os(), true)) {
145    WriteBitcodeToFile(M.get(), Out.os());
146  }
147
148  Out.keep();
149
150  return 0;
151}
152