1/*
2 * Copyright 2015, 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 "bcinfo/BitcodeWrapper.h"
18
19#include "llvm/Support/raw_ostream.h"
20
21#include "BitWriter_2_9/ReaderWriter_2_9.h"
22#include "BitWriter_2_9_func/ReaderWriter_2_9_func.h"
23#include "BitWriter_3_2/ReaderWriter_3_2.h"
24
25#include "slang_assert.h"
26#include "slang_bitcode_gen.h"
27#include "slang_version.h"
28#include "llvm/Bitcode/ReaderWriter.h"
29
30namespace slang {
31
32void writeBitcode(llvm::raw_ostream &Out,
33                  const llvm::Module &M,
34                  uint32_t TargetAPI,
35                  uint32_t OptimizationLevel,
36                  bool GenerateDebugInfo) {
37  std::string BitcodeStr;
38  llvm::raw_string_ostream Bitcode(BitcodeStr);
39
40  // The older bitcode writers will produce invalid bitcode if the -g
41  // flag is set using WriteBitcodeToFile. As such we use the ToT writer
42  // when -g is set. However, this will produce a bitcode file linked to
43  // this version of LLVM as the debug info format can change between
44  // versions.
45  // If bcc receives a bitcode file with a format of debug info
46  // which is either ahead or behind the version it is expecting it will
47  // fail the verification stage. Failing this stage results in the bitcode
48  // loader returning null and the compiler will terminate abruptly. Bitcode
49  // files with debug info are as such only capable of targeting devices with
50  // LLVM libraries with the same debug info version as the version of slang
51  // which was used to compile the file. This is due to the fact that LLVM
52  // offers no backwards or forwards compatibility guarantee for its debug
53  // bitcode. At the moment the only practical guarantee which can be made
54  // is that the debug bitcode emitted by any slang will work with the bcc
55  // version which was newest at the time when llvm-rs-cc was built.
56  if (GenerateDebugInfo) {
57    llvm::WriteBitcodeToFile(&M, Bitcode);
58  } else {
59    // Create the bitcode.
60    switch (TargetAPI) {
61    case SLANG_HC_TARGET_API:
62    case SLANG_HC_MR1_TARGET_API:
63    case SLANG_HC_MR2_TARGET_API: {
64      // Pre-ICS targets must use the LLVM 2.9 BitcodeWriter
65      llvm_2_9::WriteBitcodeToFile(&M, Bitcode);
66      break;
67    }
68    case SLANG_ICS_TARGET_API:
69    case SLANG_ICS_MR1_TARGET_API: {
70      // ICS targets must use the LLVM 2.9_func BitcodeWriter
71      llvm_2_9_func::WriteBitcodeToFile(&M, Bitcode);
72      break;
73    }
74    default: {
75      if (TargetAPI != SLANG_DEVELOPMENT_TARGET_API &&
76          (TargetAPI < SLANG_MINIMUM_TARGET_API ||
77           TargetAPI > SLANG_MAXIMUM_TARGET_API)) {
78        slangAssert(false && "Invalid target API value");
79      }
80      // Switch to the 3.2 BitcodeWriter by default, and don't use
81      // LLVM's included BitcodeWriter at all (for now).
82      llvm_3_2::WriteBitcodeToFile(&M, Bitcode);
83      break;
84    }
85    }
86  }
87
88  const uint32_t CompilerVersion = SlangVersion::CURRENT;
89
90  // Create the bitcode wrapper.
91  bcinfo::AndroidBitcodeWrapper Wrapper;
92  size_t ActualWrapperLen = bcinfo::writeAndroidBitcodeWrapper(
93        &Wrapper, Bitcode.str().length(), TargetAPI,
94        CompilerVersion, OptimizationLevel);
95
96  slangAssert(ActualWrapperLen > 0);
97
98  // Write out the file.
99  Out.write(reinterpret_cast<char*>(&Wrapper), ActualWrapperLen);
100  Out << Bitcode.str();
101}
102
103}  // namespace slang
104