BitcodeTranslator.cpp revision f21590eae009b4f596d7e448d0b8e142c46fc382 
1/*
2 * Copyright 2011-2012, 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/BitcodeTranslator.h"
18
19#include "bcinfo/BitcodeWrapper.h"
20
21#include "BitReader_2_7/BitReader_2_7.h"
22#include "BitReader_3_0/BitReader_3_0.h"
23
24#include "BitWriter_3_2/ReaderWriter_3_2.h"
25
26#define LOG_TAG "bcinfo"
27#include <cutils/log.h>
28
29#include "llvm/Bitcode/BitstreamWriter.h"
30#include "llvm/Bitcode/ReaderWriter.h"
31#include "llvm/IR/LLVMContext.h"
32#include "llvm/IR/Module.h"
33#include "llvm/Support/MemoryBuffer.h"
34#include "llvm/Support/raw_ostream.h"
35
36#include <cstdlib>
37#include <climits>
38
39namespace bcinfo {
40
41/**
42 * Define minimum and maximum target API versions. These correspond to the
43 * same API levels used by the standard Android SDK.
44 *
45 * LLVM 2.7
46 *  11 - Honeycomb
47 *  12 - Honeycomb MR1
48 *  13 - Honeycomb MR2
49 *
50 * LLVM 3.0
51 *  14 - Ice Cream Sandwich
52 *  15 - Ice Cream Sandwich MR1
53 *
54 * LLVM 3.1
55 *  16 - Ice Cream Sandwich MR2
56 */
57static const unsigned int kMinimumAPIVersion     = 11;
58static const unsigned int kMaximumAPIVersion     = RS_VERSION;
59static const unsigned int kCurrentAPIVersion     = 10000;
60static const unsigned int kDevelopmentAPIVersion = UINT_MAX;
61
62/**
63 * The minimum version which does not require translation (i.e. is already
64 * compatible with LLVM's default bitcode reader).
65 */
66static const unsigned int kMinimumUntranslatedVersion = 16;
67static const unsigned int kMinimumCompatibleVersion_LLVM_3_0 = 14;
68static const unsigned int kMinimumCompatibleVersion_LLVM_2_7 = 11;
69
70
71BitcodeTranslator::BitcodeTranslator(const char *bitcode, size_t bitcodeSize,
72                                     unsigned int version)
73    : mBitcode(bitcode), mBitcodeSize(bitcodeSize), mTranslatedBitcode(NULL),
74      mTranslatedBitcodeSize(0), mVersion(version) {
75  return;
76}
77
78
79BitcodeTranslator::~BitcodeTranslator() {
80  if (mVersion < kMinimumUntranslatedVersion) {
81    // We didn't actually do a translation in the alternate case, so deleting
82    // the bitcode would be improper.
83    delete [] mTranslatedBitcode;
84  }
85  mTranslatedBitcode = NULL;
86  return;
87}
88
89
90bool BitcodeTranslator::translate() {
91  if (!mBitcode || !mBitcodeSize) {
92    ALOGE("Invalid/empty bitcode");
93    return false;
94  }
95
96  BitcodeWrapper BCWrapper(mBitcode, mBitcodeSize);
97  if (BCWrapper.getTargetAPI() != mVersion) {
98    ALOGE("Bitcode wrapper (%u) and translator (%u) disagree about target API",
99          BCWrapper.getTargetAPI(), mVersion);
100  }
101
102  if ((mVersion != kDevelopmentAPIVersion) &&
103      (mVersion != kCurrentAPIVersion)     &&
104       ((mVersion < kMinimumAPIVersion) ||
105        (mVersion > kMaximumAPIVersion))) {
106    ALOGE("Invalid API version: %u is out of range ('%u' - '%u')", mVersion,
107         kMinimumAPIVersion, kMaximumAPIVersion);
108    return false;
109  }
110
111  // We currently don't need to transcode any API version higher than 14 or
112  // the current API version (i.e. 10000)
113  if (mVersion >= kMinimumUntranslatedVersion) {
114    mTranslatedBitcode = mBitcode;
115    mTranslatedBitcodeSize = mBitcodeSize;
116    return true;
117  }
118
119  // Do the actual transcoding by invoking a 2.7-era bitcode reader that can
120  // then write the bitcode back out in a more modern (acceptable) version.
121  std::unique_ptr<llvm::LLVMContext> mContext(new llvm::LLVMContext());
122  std::unique_ptr<llvm::MemoryBuffer> MEM(
123    llvm::MemoryBuffer::getMemBuffer(
124      llvm::StringRef(mBitcode, mBitcodeSize), "", false));
125  std::string error;
126
127  // Module ownership is handled by the context, so we don't need to free it.
128  llvm::Module *module = NULL;
129
130  if (mVersion >= kMinimumCompatibleVersion_LLVM_3_0) {
131    module = llvm_3_0::ParseBitcodeFile(MEM.get(), *mContext, &error);
132  } else if (mVersion >= kMinimumCompatibleVersion_LLVM_2_7) {
133    module = llvm_2_7::ParseBitcodeFile(MEM.get(), *mContext, &error);
134  } else {
135    ALOGE("No compatible bitcode reader for API version %d", mVersion);
136    return false;
137  }
138
139  if (!module) {
140    ALOGE("Could not parse bitcode file");
141    ALOGE("%s", error.c_str());
142    return false;
143  }
144
145  std::string Buffer;
146
147  llvm::raw_string_ostream OS(Buffer);
148  // Use the LLVM 3.2 bitcode writer, instead of the top-of-tree version.
149  llvm_3_2::WriteBitcodeToFile(module, OS);
150  OS.flush();
151
152  AndroidBitcodeWrapper wrapper;
153  size_t actualWrapperLen = writeAndroidBitcodeWrapper(
154      &wrapper, Buffer.size(), BCWrapper.getTargetAPI(),
155      BCWrapper.getCompilerVersion(), BCWrapper.getOptimizationLevel());
156  if (!actualWrapperLen) {
157    ALOGE("Couldn't produce bitcode wrapper!");
158    return false;
159  }
160
161  mTranslatedBitcodeSize = actualWrapperLen + Buffer.size();
162  char *c = new char[mTranslatedBitcodeSize];
163  memcpy(c, &wrapper, actualWrapperLen);
164  memcpy(c + actualWrapperLen, Buffer.c_str(), Buffer.size());
165
166  mTranslatedBitcode = c;
167
168  return true;
169}
170
171}  // namespace bcinfo
172