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      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 #include "StripUnkAttr/strip_unknown_attributes.h"
     27 
     28 #define LOG_TAG "bcinfo"
     29 #include <log/log.h>
     30 
     31 #include "llvm/Bitcode/BitstreamWriter.h"
     32 #include "llvm/Bitcode/ReaderWriter.h"
     33 #include "llvm/IR/LLVMContext.h"
     34 #include "llvm/IR/Module.h"
     35 #include "llvm/Support/MemoryBuffer.h"
     36 #include "llvm/Support/raw_ostream.h"
     37 
     38 #include <cstdlib>
     39 #include <climits>
     40 
     41 namespace bcinfo {
     42 
     43 /**
     44  * Define minimum and maximum target API versions. These correspond to the
     45  * same API levels used by the standard Android SDK.
     46  *
     47  * LLVM 2.7
     48  *  11 - Honeycomb
     49  *  12 - Honeycomb MR1
     50  *  13 - Honeycomb MR2
     51  *
     52  * LLVM 3.0
     53  *  14 - Ice Cream Sandwich
     54  *  15 - Ice Cream Sandwich MR1
     55  *
     56  * LLVM 3.1
     57  *  16 - Ice Cream Sandwich MR2
     58  */
     59 static const unsigned int kMinimumAPIVersion     = 11;
     60 static const unsigned int kMaximumAPIVersion     = RS_VERSION;
     61 static const unsigned int kCurrentAPIVersion     = 10000;
     62 static const unsigned int kDevelopmentAPIVersion = UINT_MAX;
     63 
     64 /**
     65  * The minimum version which does not require translation (i.e. is already
     66  * compatible with LLVM's default bitcode reader).
     67  */
     68 static const unsigned int kMinimumUntranslatedVersion = 16;
     69 static const unsigned int kMinimumCompatibleVersion_LLVM_3_0 = 14;
     70 static const unsigned int kMinimumCompatibleVersion_LLVM_2_7 = 11;
     71 
     72 
     73 static void stripUnknownAttributes(llvm::Module *M) {
     74   for (llvm::Function &F : *M)
     75     slang::stripUnknownAttributes(F);
     76 }
     77 
     78 BitcodeTranslator::BitcodeTranslator(const char *bitcode, size_t bitcodeSize,
     79                                      unsigned int version)
     80     : mBitcode(bitcode), mBitcodeSize(bitcodeSize), mTranslatedBitcode(nullptr),
     81       mTranslatedBitcodeSize(0), mVersion(version) {
     82   return;
     83 }
     84 
     85 
     86 BitcodeTranslator::~BitcodeTranslator() {
     87   if (mVersion < kMinimumUntranslatedVersion) {
     88     // We didn't actually do a translation in the alternate case, so deleting
     89     // the bitcode would be improper.
     90     delete [] mTranslatedBitcode;
     91   }
     92   mTranslatedBitcode = nullptr;
     93   return;
     94 }
     95 
     96 
     97 bool BitcodeTranslator::translate() {
     98   if (!mBitcode || !mBitcodeSize) {
     99     ALOGE("Invalid/empty bitcode");
    100     return false;
    101   }
    102 
    103   BitcodeWrapper BCWrapper(mBitcode, mBitcodeSize);
    104   if (BCWrapper.getTargetAPI() != mVersion) {
    105     ALOGE("Bitcode wrapper (%u) and translator (%u) disagree about target API",
    106           BCWrapper.getTargetAPI(), mVersion);
    107   }
    108 
    109   if ((mVersion != kDevelopmentAPIVersion) &&
    110       (mVersion != kCurrentAPIVersion)     &&
    111        ((mVersion < kMinimumAPIVersion) ||
    112         (mVersion > kMaximumAPIVersion))) {
    113     ALOGE("Invalid API version: %u is out of range ('%u' - '%u')", mVersion,
    114          kMinimumAPIVersion, kMaximumAPIVersion);
    115     return false;
    116   }
    117 
    118   // We currently don't need to transcode any API version higher than 14 or
    119   // the current API version (i.e. 10000)
    120   if (mVersion >= kMinimumUntranslatedVersion) {
    121     mTranslatedBitcode = mBitcode;
    122     mTranslatedBitcodeSize = mBitcodeSize;
    123     return true;
    124   }
    125 
    126   // Do the actual transcoding by invoking a 2.7-era bitcode reader that can
    127   // then write the bitcode back out in a more modern (acceptable) version.
    128   std::unique_ptr<llvm::LLVMContext> mContext(new llvm::LLVMContext());
    129   std::unique_ptr<llvm::MemoryBuffer> MEM(
    130     llvm::MemoryBuffer::getMemBuffer(
    131       llvm::StringRef(mBitcode, mBitcodeSize), "", false));
    132   std::string error;
    133   llvm::ErrorOr<llvm::MemoryBufferRef> MBOrErr = MEM->getMemBufferRef();
    134 
    135   llvm::ErrorOr<llvm::Module *> MOrErr(nullptr);
    136 
    137   if (mVersion >= kMinimumCompatibleVersion_LLVM_3_0) {
    138     MOrErr = llvm_3_0::parseBitcodeFile(*MBOrErr, *mContext);
    139   } else if (mVersion >= kMinimumCompatibleVersion_LLVM_2_7) {
    140     MOrErr = llvm_2_7::parseBitcodeFile(*MBOrErr, *mContext);
    141   } else {
    142     ALOGE("No compatible bitcode reader for API version %d", mVersion);
    143     return false;
    144   }
    145 
    146   if (std::error_code EC = MOrErr.getError()) {
    147     ALOGE("Could not parse bitcode file");
    148     ALOGE("%s", EC.message().c_str());
    149     return false;
    150   }
    151 
    152   // Module ownership is handled by the context, so we don't need to free it.
    153   llvm::Module *module = MOrErr.get();
    154 
    155   stripUnknownAttributes(module);
    156 
    157   std::string Buffer;
    158 
    159   llvm::raw_string_ostream OS(Buffer);
    160   // Use the LLVM 3.2 bitcode writer, instead of the top-of-tree version.
    161   llvm_3_2::WriteBitcodeToFile(module, OS);
    162   OS.flush();
    163 
    164   AndroidBitcodeWrapper wrapper;
    165   size_t actualWrapperLen = writeAndroidBitcodeWrapper(
    166       &wrapper, Buffer.size(), kMinimumUntranslatedVersion,
    167       BCWrapper.getCompilerVersion(), BCWrapper.getOptimizationLevel());
    168   if (!actualWrapperLen) {
    169     ALOGE("Couldn't produce bitcode wrapper!");
    170     return false;
    171   }
    172 
    173   mTranslatedBitcodeSize = actualWrapperLen + Buffer.size();
    174   char *c = new char[mTranslatedBitcodeSize];
    175   memcpy(c, &wrapper, actualWrapperLen);
    176   memcpy(c + actualWrapperLen, Buffer.c_str(), Buffer.size());
    177 
    178   mTranslatedBitcode = c;
    179 
    180   return true;
    181 }
    182 
    183 }  // namespace bcinfo
    184