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 "strip_unknown_attributes.h"
18
19namespace slang {
20
21StripUnknownAttributes::StripUnknownAttributes() : ModulePass(ID) {
22}
23
24
25bool StripUnknownAttributes::runOnFunction(llvm::Function &F) {
26  bool changed = false;
27  for (llvm::Function::arg_iterator I = F.arg_begin(), E = F.arg_end();
28       I != E; ++I) {
29    llvm::Argument &A = *I;
30    // Remove any readnone/readonly attributes from function parameters.
31    if (A.onlyReadsMemory()) {
32      llvm::AttrBuilder B;
33      B.addAttribute(llvm::Attribute::ReadNone);
34      B.addAttribute(llvm::Attribute::ReadOnly);
35      llvm::AttributeSet ToStrip = llvm::AttributeSet::get(F.getContext(),
36          A.getArgNo() + 1, B);
37      A.removeAttr(ToStrip);
38      changed = true;
39    }
40  }
41  return changed;
42}
43
44
45bool StripUnknownAttributes::runOnModule(llvm::Module &M) {
46  bool Changed = false;
47  for (llvm::Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
48    Changed |= runOnFunction(*I);
49  }
50  return Changed;
51}
52
53
54llvm::ModulePass * createStripUnknownAttributesPass() {
55  return new StripUnknownAttributes();
56}
57
58
59char StripUnknownAttributes::ID = 0;
60static llvm::RegisterPass<StripUnknownAttributes> RPSUA(
61    "StripUnknownAttributes", "Strip Unknown Attributes Pass");
62
63}  // namespace slang
64