1/*
2 * Copyright 2017, 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 "RemoveNonkernelsPass.h"
18
19#include "llvm/ADT/Triple.h"
20#include "llvm/IR/Constants.h"
21#include "llvm/IR/Module.h"
22#include "llvm/Pass.h"
23#include "llvm/Support/Debug.h"
24#include "llvm/Support/raw_ostream.h"
25
26#include "Context.h"
27
28#define DEBUG_TYPE "rs2spirv-remove"
29
30using namespace llvm;
31
32namespace rs2spirv {
33
34namespace {
35
36void HandleTargetTriple(llvm::Module &M) {
37  Triple TT(M.getTargetTriple());
38  auto Arch = TT.getArch();
39
40  StringRef NewTriple;
41  switch (Arch) {
42  default:
43    llvm_unreachable("Unrecognized architecture");
44    break;
45  case Triple::arm:
46    NewTriple = "spir-unknown-unknown";
47    break;
48  case Triple::aarch64:
49    NewTriple = "spir64-unknown-unknown";
50    break;
51  case Triple::spir:
52  case Triple::spir64:
53    DEBUG(dbgs() << "!!! Already a spir triple !!!\n");
54  }
55
56  DEBUG(dbgs() << "New triple:\t" << NewTriple << "\n");
57  M.setTargetTriple(NewTriple);
58}
59
60class RemoveNonkernelsPass : public ModulePass {
61public:
62  static char ID;
63  explicit RemoveNonkernelsPass() : ModulePass(ID) {}
64
65  const char *getPassName() const override { return "RemoveNonkernelsPass"; }
66
67  bool runOnModule(Module &M) override {
68    DEBUG(dbgs() << "RemoveNonkernelsPass\n");
69    DEBUG(M.dump());
70
71    HandleTargetTriple(M);
72
73    rs2spirv::Context &Ctxt = rs2spirv::Context::getInstance();
74
75    if (Ctxt.getNumForEachKernel() == 0) {
76      DEBUG(dbgs() << "RemoveNonkernelsPass detected no kernel\n");
77      // Returns false, since no modification is made to the Module.
78      return false;
79    }
80
81    std::vector<Function *> Functions;
82    for (auto &F : M.functions()) {
83      Functions.push_back(&F);
84    }
85
86    for (auto &F : Functions) {
87      if (F->isDeclaration())
88        continue;
89
90      if (Ctxt.isForEachKernel(F->getName())) {
91        continue; // Skip kernels.
92      }
93
94      F->replaceAllUsesWith(UndefValue::get((Type *)F->getType()));
95      F->eraseFromParent();
96
97      DEBUG(dbgs() << "Removed:\t" << F->getName() << '\n');
98    }
99
100    DEBUG(M.dump());
101    DEBUG(dbgs() << "Done removal\n");
102
103    // Returns true, because the pass modifies the Module.
104    return true;
105  }
106};
107
108} // namespace
109
110char RemoveNonkernelsPass::ID = 0;
111
112ModulePass *createRemoveNonkernelsPass() {
113  return new RemoveNonkernelsPass();
114}
115
116} // namespace rs2spirv
117