1    :  // Copyright 2012 Google Inc. All Rights Reserved.
   2    :  //
   3    :  // Licensed under the Apache License, Version 2.0 (the "License");
   4    :  // you may not use this file except in compliance with the License.
   5    :  // You may obtain a copy of the License at
   6    :  //
   7    :  //     http://www.apache.org/licenses/LICENSE-2.0
   8    :  //
   9    :  // Unless required by applicable law or agreed to in writing, software
  10    :  // distributed under the License is distributed on an "AS IS" BASIS,
  11    :  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12    :  // See the License for the specific language governing permissions and
  13    :  // limitations under the License.
  14    :  
  15    :  #include "syzygy/block_graph/transform.h"
  16    :  
  17    :  #include "syzygy/block_graph/basic_block_decomposer.h"
  18    :  #include "syzygy/block_graph/block_builder.h"
  19    :  #include "syzygy/block_graph/block_util.h"
  20    :  
  21    :  namespace block_graph {
  22    :  
  23    :  bool ApplyBlockGraphTransform(BlockGraphTransformInterface* transform,
  24    :                                BlockGraph* block_graph,
  25  E :                                BlockGraph::Block* header_block) {
  26  E :    DCHECK(transform != NULL);
  27  E :    DCHECK(transform->name() != NULL);
  28  E :    DCHECK_GT(strlen(transform->name()), 0u);
  29  E :    DCHECK(block_graph != NULL);
  30  E :    DCHECK(header_block != NULL);
  31    :  
  32    :    // Get the ID of the header block. As a sanity check we want to ensure
  33    :    // that it still exists after the transform.
  34  E :    BlockGraph::BlockId header_block_id = header_block->id();
  35    :  
  36  E :    if (!transform->TransformBlockGraph(block_graph, header_block)) {
  37  E :      LOG(ERROR) << "Transform \"" << transform->name() << "\" failed.";
  38  E :      return false;
  39    :    }
  40    :  
  41    :    // Ensure that the header block still exists. If it was changed, it needs
  42    :    // to have been changed in place.
  43  E :    BlockGraph::Block* block = block_graph->GetBlockById(header_block_id);
  44  E :    if (block == NULL) {
  45  E :      LOG(ERROR) << "Header block not found after \"" << transform->name()
  46    :                 << "\" transform.";
  47  E :      return false;
  48    :    }
  49  E :    DCHECK_EQ(header_block, block);
  50    :  
  51  E :    return true;
  52  E :  }
  53    :  
  54    :  bool ApplyBasicBlockSubGraphTransform(
  55    :      BasicBlockSubGraphTransformInterface* transform,
  56    :      BlockGraph* block_graph,
  57    :      BlockGraph::Block* block,
  58  E :      BlockVector* new_blocks) {
  59  E :    DCHECK(transform != NULL);
  60  E :    DCHECK(block_graph != NULL);
  61  E :    DCHECK(block != NULL);
  62  E :    DCHECK_EQ(BlockGraph::CODE_BLOCK, block->type());
  63  E :    DCHECK(CodeBlockAttributesAreBasicBlockSafe(block));
  64    :  
  65    :    // Decompose block to basic blocks.
  66  E :    BasicBlockSubGraph subgraph;
  67  E :    BasicBlockDecomposer bb_decomposer(block, &subgraph);
  68  E :    if (!bb_decomposer.Decompose())
  69  i :      return false;
  70    :  
  71    :    // Call the transform.
  72  E :    if (!transform->TransformBasicBlockSubGraph(block_graph, &subgraph))
  73  E :      return false;
  74    :  
  75    :    // Update the block-graph post transform.
  76  E :    BlockBuilder builder(block_graph);
  77  E :    if (!builder.Merge(&subgraph))
  78  i :      return false;
  79    :  
  80  E :    if (new_blocks != NULL) {
  81    :      new_blocks->assign(builder.new_blocks().begin(),
  82  E :                         builder.new_blocks().end());
  83    :    }
  84    :  
  85  E :    return true;
  86  E :  }
  87    :  
  88    :  }  // namespace block_graph