BitcodeTranslator.cpp revision 8dbca8e957dab1db77dffbe10c14c54d4b439be6 
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/ADT/OwningPtr.h"
30#include "llvm/Bitcode/BitstreamWriter.h"
31#include "llvm/Bitcode/ReaderWriter.h"
32#include "llvm/IR/LLVMContext.h"
33#include "llvm/IR/Module.h"
34#include "llvm/Support/MemoryBuffer.h"
35#include "llvm/Support/raw_ostream.h"
36
37#include <cstdlib>
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 = BCINFO_API_VERSION;
59static const unsigned int kCurrentAPIVersion = 10000;
60
61/**
62 * The minimum version which does not require translation (i.e. is already
63 * compatible with LLVM's default bitcode reader).
64 */
65static const unsigned int kMinimumUntranslatedVersion = 16;
66static const unsigned int kMinimumCompatibleVersion_LLVM_3_0 = 14;
67static const unsigned int kMinimumCompatibleVersion_LLVM_2_7 = 11;
68
69
70BitcodeTranslator::BitcodeTranslator(const char *bitcode, size_t bitcodeSize,
71                                     unsigned int version)
72    : mBitcode(bitcode), mBitcodeSize(bitcodeSize), mTranslatedBitcode(NULL),
73      mTranslatedBitcodeSize(0), mVersion(version) {
74  return;
75}
76
77
78BitcodeTranslator::~BitcodeTranslator() {
79  if (mVersion < kMinimumUntranslatedVersion) {
80    // We didn't actually do a translation in the alternate case, so deleting
81    // the bitcode would be improper.
82    delete [] mTranslatedBitcode;
83  }
84  mTranslatedBitcode = NULL;
85  return;
86}
87
88
89bool BitcodeTranslator::translate() {
90  if (!mBitcode || !mBitcodeSize) {
91    ALOGE("Invalid/empty bitcode");
92    return false;
93  }
94
95  BitcodeWrapper BCWrapper(mBitcode, mBitcodeSize);
96  if (BCWrapper.getTargetAPI() != mVersion) {
97    ALOGE("Bitcode wrapper (%u) and translator (%u) disagree about target API",
98          BCWrapper.getTargetAPI(), mVersion);
99  }
100
101  if ((mVersion != kCurrentAPIVersion) &&
102      ((mVersion < kMinimumAPIVersion) ||
103       (mVersion > kMaximumAPIVersion))) {
104    ALOGE("Invalid API version: %u is out of range ('%u' - '%u')", mVersion,
105         kMinimumAPIVersion, kMaximumAPIVersion);
106    return false;
107  }
108
109  // We currently don't need to transcode any API version higher than 14 or
110  // the current API version (i.e. 10000)
111  if (mVersion >= kMinimumUntranslatedVersion) {
112    mTranslatedBitcode = mBitcode;
113    mTranslatedBitcodeSize = mBitcodeSize;
114    return true;
115  }
116
117  // Do the actual transcoding by invoking a 2.7-era bitcode reader that can
118  // then write the bitcode back out in a more modern (acceptable) version.
119  llvm::OwningPtr<llvm::LLVMContext> mContext(new llvm::LLVMContext());
120  llvm::OwningPtr<llvm::MemoryBuffer> MEM(
121    llvm::MemoryBuffer::getMemBuffer(
122      llvm::StringRef(mBitcode, mBitcodeSize), "", false));
123  std::string error;
124
125  // Module ownership is handled by the context, so we don't need to free it.
126  llvm::Module *module = NULL;
127
128  if (mVersion >= kMinimumCompatibleVersion_LLVM_3_0) {
129    module = llvm_3_0::ParseBitcodeFile(MEM.get(), *mContext, &error);
130  } else if (mVersion >= kMinimumCompatibleVersion_LLVM_2_7) {
131    module = llvm_2_7::ParseBitcodeFile(MEM.get(), *mContext, &error);
132  } else {
133    ALOGE("No compatible bitcode reader for API version %d", mVersion);
134    return false;
135  }
136
137  if (!module) {
138    ALOGE("Could not parse bitcode file");
139    ALOGE("%s", error.c_str());
140    return false;
141  }
142
143  std::string Buffer;
144
145  llvm::raw_string_ostream OS(Buffer);
146  // Use the LLVM 3.2 bitcode writer, instead of the top-of-tree version.
147  llvm_3_2::WriteBitcodeToFile(module, OS);
148  OS.flush();
149
150  AndroidBitcodeWrapper wrapper;
151  size_t actualWrapperLen = writeAndroidBitcodeWrapper(
152      &wrapper, Buffer.size(), BCWrapper.getTargetAPI(),
153      BCWrapper.getCompilerVersion(), BCWrapper.getOptimizationLevel());
154  if (!actualWrapperLen) {
155    ALOGE("Couldn't produce bitcode wrapper!");
156    return false;
157  }
158
159  mTranslatedBitcodeSize = actualWrapperLen + Buffer.size();
160  char *c = new char[mTranslatedBitcodeSize];
161  memcpy(c, &wrapper, actualWrapperLen);
162  memcpy(c + actualWrapperLen, Buffer.c_str(), Buffer.size());
163
164  mTranslatedBitcode = c;
165
166  return true;
167}
168
169}  // namespace bcinfo
170
171