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/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ART_SRC_COMPILER_DEX_DATAFLOW_ITERATOR_H_
#define ART_SRC_COMPILER_DEX_DATAFLOW_ITERATOR_H_
#include "compiler_ir.h"
#include "mir_graph.h"
namespace art {
/*
* This class supports iterating over lists of basic blocks in various
* interesting orders. Note that for efficiency, the visit orders have been pre-computed.
* The order itself will not change during the iteration. However, for some uses,
* auxiliary data associated with the basic blocks may be changed during the iteration,
* necessitating another pass over the list.
*
* To support this usage, we have is_iterative_. If false, the iteration is a one-shot
* pass through the pre-computed list using Next(). If true, the caller must tell the
* iterator whether a change has been made that necessitates another pass. Use
* Next(had_change) for this. The general idea is that the iterative_ use case means
* that the iterator will keep repeating the full basic block list until a complete pass
* is made through it with no changes. Note that calling Next(true) does not affect
* the iteration order or short-curcuit the current pass - it simply tells the iterator
* that once it has finished walking through the block list it should reset and do another
* full pass through the list.
*/
class DataflowIterator {
public:
virtual ~DataflowIterator(){}
// Return the next BasicBlock* to visit.
BasicBlock* Next() {
DCHECK(!is_iterative_);
return NextBody(false);
}
/*
* Return the next BasicBlock* to visit, and tell the iterator whether any change
* has occurred that requires another full pass over the block list.
*/
BasicBlock* Next(bool had_change) {
DCHECK(is_iterative_);
return NextBody(had_change);
}
protected:
DataflowIterator(MIRGraph* mir_graph, bool is_iterative, int start_idx, int end_idx,
bool reverse)
: mir_graph_(mir_graph),
is_iterative_(is_iterative),
start_idx_(start_idx),
end_idx_(end_idx),
reverse_(reverse),
block_id_list_(NULL),
idx_(0),
changed_(false) {}
virtual BasicBlock* NextBody(bool had_change) ALWAYS_INLINE;
MIRGraph* const mir_graph_;
const bool is_iterative_;
const int start_idx_;
const int end_idx_;
const bool reverse_;
GrowableArray<int>* block_id_list_;
int idx_;
bool changed_;
}; // DataflowIterator
class ReachableNodesIterator : public DataflowIterator {
public:
ReachableNodesIterator(MIRGraph* mir_graph, bool is_iterative)
: DataflowIterator(mir_graph, is_iterative, 0,
mir_graph->GetNumReachableBlocks(), false) {
idx_ = start_idx_;
block_id_list_ = mir_graph->GetDfsOrder();
}
};
class PreOrderDfsIterator : public DataflowIterator {
public:
PreOrderDfsIterator(MIRGraph* mir_graph, bool is_iterative)
: DataflowIterator(mir_graph, is_iterative, 0,
mir_graph->GetNumReachableBlocks(), false) {
idx_ = start_idx_;
block_id_list_ = mir_graph->GetDfsOrder();
}
};
class PostOrderDfsIterator : public DataflowIterator {
public:
PostOrderDfsIterator(MIRGraph* mir_graph, bool is_iterative)
: DataflowIterator(mir_graph, is_iterative, 0,
mir_graph->GetNumReachableBlocks(), false) {
idx_ = start_idx_;
block_id_list_ = mir_graph->GetDfsPostOrder();
}
};
class ReversePostOrderDfsIterator : public DataflowIterator {
public:
ReversePostOrderDfsIterator(MIRGraph* mir_graph, bool is_iterative)
: DataflowIterator(mir_graph, is_iterative,
mir_graph->GetNumReachableBlocks() -1, 0, true) {
idx_ = start_idx_;
block_id_list_ = mir_graph->GetDfsPostOrder();
}
};
class PostOrderDOMIterator : public DataflowIterator {
public:
PostOrderDOMIterator(MIRGraph* mir_graph, bool is_iterative)
: DataflowIterator(mir_graph, is_iterative, 0,
mir_graph->GetNumReachableBlocks(), false) {
idx_ = start_idx_;
block_id_list_ = mir_graph->GetDomPostOrder();
}
};
class AllNodesIterator : public DataflowIterator {
public:
AllNodesIterator(MIRGraph* mir_graph, bool is_iterative)
: DataflowIterator(mir_graph, is_iterative, 0, 0, false) {
all_nodes_iterator_ =
new (mir_graph->GetArena()) GrowableArray<BasicBlock*>::Iterator (mir_graph->GetBlockList());
}
void Reset() {
all_nodes_iterator_->Reset();
}
BasicBlock* NextBody(bool had_change) ALWAYS_INLINE;
private:
GrowableArray<BasicBlock*>::Iterator* all_nodes_iterator_;
};
} // namespace art
#endif // ART_SRC_COMPILER_DEX_DATAFLOW_ITERATOR_H_
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