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// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_COMPILER_ESCAPE_ANALYSIS_REDUCER_H_
#define V8_COMPILER_ESCAPE_ANALYSIS_REDUCER_H_
#include "src/base/compiler-specific.h"
#include "src/compiler/escape-analysis.h"
#include "src/compiler/graph-reducer.h"
#include "src/globals.h"
namespace v8 {
namespace internal {
namespace compiler {
class Deduplicator;
class JSGraph;
// Perform hash-consing when creating or mutating nodes. Used to avoid duplicate
// nodes when creating ObjectState, StateValues and FrameState nodes
class NodeHashCache {
public:
NodeHashCache(Graph* graph, Zone* zone)
: graph_(graph), cache_(zone), temp_nodes_(zone) {}
// Handle to a conceptually new mutable node. Tries to re-use existing nodes
// and to recycle memory if possible.
class Constructor {
public:
// Construct a new node as a clone of [from].
Constructor(NodeHashCache* cache, Node* from)
: node_cache_(cache), from_(from), tmp_(nullptr) {}
// Construct a new node from scratch.
Constructor(NodeHashCache* cache, const Operator* op, int input_count,
Node** inputs, Type* type);
// Modify the new node.
void ReplaceValueInput(Node* input, int i) {
if (!tmp_ && input == NodeProperties::GetValueInput(from_, i)) return;
Node* node = MutableNode();
NodeProperties::ReplaceValueInput(node, input, i);
}
void ReplaceInput(Node* input, int i) {
if (!tmp_ && input == from_->InputAt(i)) return;
Node* node = MutableNode();
node->ReplaceInput(i, input);
}
// Obtain the mutated node or a cached copy. Invalidates the [Constructor].
Node* Get();
private:
Node* MutableNode();
NodeHashCache* node_cache_;
// Original node, copied on write.
Node* from_;
// Temporary node used for mutations, can be recycled if cache is hit.
Node* tmp_;
};
private:
Node* Query(Node* node);
void Insert(Node* node) { cache_.insert(node); }
Graph* graph_;
struct NodeEquals {
bool operator()(Node* a, Node* b) const {
return NodeProperties::Equals(a, b);
}
};
struct NodeHashCode {
size_t operator()(Node* n) const { return NodeProperties::HashCode(n); }
};
ZoneUnorderedSet<Node*, NodeHashCode, NodeEquals> cache_;
// Unused nodes whose memory can be recycled.
ZoneVector<Node*> temp_nodes_;
};
// Modify the graph according to the information computed in the previous phase.
class V8_EXPORT_PRIVATE EscapeAnalysisReducer final
: public NON_EXPORTED_BASE(AdvancedReducer) {
public:
EscapeAnalysisReducer(Editor* editor, JSGraph* jsgraph,
EscapeAnalysisResult analysis_result, Zone* zone);
Reduction Reduce(Node* node) override;
const char* reducer_name() const override { return "EscapeAnalysisReducer"; }
void Finalize() override;
// Verifies that all virtual allocation nodes have been dealt with. Run it
// after this reducer has been applied.
void VerifyReplacement() const;
private:
void ReduceFrameStateInputs(Node* node);
Node* ReduceDeoptState(Node* node, Node* effect, Deduplicator* deduplicator);
Node* ObjectIdNode(const VirtualObject* vobject);
Node* MaybeGuard(Node* original, Node* replacement);
JSGraph* jsgraph() const { return jsgraph_; }
EscapeAnalysisResult analysis_result() const { return analysis_result_; }
Zone* zone() const { return zone_; }
JSGraph* const jsgraph_;
EscapeAnalysisResult analysis_result_;
ZoneVector<Node*> object_id_cache_;
NodeHashCache node_cache_;
ZoneSet<Node*> arguments_elements_;
Zone* const zone_;
DISALLOW_COPY_AND_ASSIGN(EscapeAnalysisReducer);
};
} // namespace compiler
} // namespace internal
} // namespace v8
#endif // V8_COMPILER_ESCAPE_ANALYSIS_REDUCER_H_
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