Source/JavaScriptCore/dfg/DFGInPlaceAbstractState.h - WebKit - Git at Google

 /*
  * Copyright (C) 2013-2018 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #pragma once

 #if ENABLE(DFG_JIT)

 #include "DFGAbstractInterpreterClobberState.h"
 #include "DFGAbstractValue.h"
 #include "DFGBranchDirection.h"
 #include "DFGFlowMap.h"
 #include "DFGGraph.h"
 #include "DFGNode.h"

 namespace JSC { namespace DFG {

 class InPlaceAbstractState {
     WTF_MAKE_FAST_ALLOCATED;
 public:
     InPlaceAbstractState(Graph&);

     ~InPlaceAbstractState();

     explicit operator bool() const { return true; }

     void createValueForNode(NodeFlowProjection) { }

     ALWAYS_INLINE AbstractValue& fastForward(AbstractValue& value)
     {
         value.fastForwardTo(m_effectEpoch);
         return value;
     }

     ALWAYS_INLINE void fastForwardAndFilterUnproven(AbstractValue& value, SpeculatedType type)
     {
         value.fastForwardToAndFilterUnproven(m_effectEpoch, type);
     }

     ALWAYS_INLINE AbstractValue& forNodeWithoutFastForward(NodeFlowProjection node)
     {
         return m_abstractValues.at(node);
     }

     ALWAYS_INLINE AbstractValue& forNodeWithoutFastForward(Edge edge)
     {
         return forNodeWithoutFastForward(edge.node());
     }

     ALWAYS_INLINE AbstractValue& forNode(NodeFlowProjection node)
     {
         return fastForward(m_abstractValues.at(node));
     }

     ALWAYS_INLINE AbstractValue& forNode(Edge edge)
     {
         return forNode(edge.node());
     }

     ALWAYS_INLINE void clearForNode(NodeFlowProjection node)
     {
         AbstractValue& value = m_abstractValues.at(node);
         value.clear();
         value.m_effectEpoch = m_effectEpoch;
     }

     ALWAYS_INLINE void clearForNode(Edge edge)
     {
         clearForNode(edge.node());
     }

     template<typename... Arguments>
     ALWAYS_INLINE void setForNode(NodeFlowProjection node, Arguments&&... arguments)
     {
         AbstractValue& value = m_abstractValues.at(node);
         value.set(m_graph, std::forward<Arguments>(arguments)...);
         value.m_effectEpoch = m_effectEpoch;
     }

     template<typename... Arguments>
     ALWAYS_INLINE void setForNode(Edge edge, Arguments&&... arguments)
     {
         setForNode(edge.node(), std::forward<Arguments>(arguments)...);
     }

     template<typename... Arguments>
     ALWAYS_INLINE void setTypeForNode(NodeFlowProjection node, Arguments&&... arguments)
     {
         AbstractValue& value = m_abstractValues.at(node);
         value.setType(m_graph, std::forward<Arguments>(arguments)...);
         value.m_effectEpoch = m_effectEpoch;
     }

     template<typename... Arguments>
     ALWAYS_INLINE void setTypeForNode(Edge edge, Arguments&&... arguments)
     {
         setTypeForNode(edge.node(), std::forward<Arguments>(arguments)...);
     }

     template<typename... Arguments>
     ALWAYS_INLINE void setNonCellTypeForNode(NodeFlowProjection node, Arguments&&... arguments)
     {
         AbstractValue& value = m_abstractValues.at(node);
         value.setNonCellType(std::forward<Arguments>(arguments)...);
         value.m_effectEpoch = m_effectEpoch;
     }

     template<typename... Arguments>
     ALWAYS_INLINE void setNonCellTypeForNode(Edge edge, Arguments&&... arguments)
     {
         setNonCellTypeForNode(edge.node(), std::forward<Arguments>(arguments)...);
     }

     ALWAYS_INLINE void makeBytecodeTopForNode(NodeFlowProjection node)
     {
         AbstractValue& value = m_abstractValues.at(node);
         value.makeBytecodeTop();
         value.m_effectEpoch = m_effectEpoch;
     }

     ALWAYS_INLINE void makeBytecodeTopForNode(Edge edge)
     {
         makeBytecodeTopForNode(edge.node());
     }

     ALWAYS_INLINE void makeHeapTopForNode(NodeFlowProjection node)
     {
         AbstractValue& value = m_abstractValues.at(node);
         value.makeHeapTop();
         value.m_effectEpoch = m_effectEpoch;
     }

     ALWAYS_INLINE void makeHeapTopForNode(Edge edge)
     {
         makeHeapTopForNode(edge.node());
     }

     Operands<AbstractValue>& variablesForDebugging();

     unsigned size() const { return m_variables.size(); }
     unsigned numberOfArguments() const { return m_variables.numberOfArguments(); }
     unsigned numberOfLocals() const { return m_variables.numberOfLocals(); }
     unsigned numberOfTmps() const { return m_variables.numberOfTmps(); }

     AbstractValue& atIndex(size_t index)
     {
         activateVariableIfNecessary(index);
         return fastForward(m_variables[index]);
     }

     AbstractValue& operand(Operand operand)
     {
         return atIndex(m_variables.operandIndex(operand));
     }

     AbstractValue& local(size_t index)
     {
         return atIndex(m_variables.localIndex(index));
     }

     AbstractValue& argument(size_t index)
     {
         return atIndex(m_variables.argumentIndex(index));
     }

     // Call this before beginning CFA to initialize the abstract values of
     // arguments, and to indicate which blocks should be listed for CFA
     // execution.
     void initialize();

     // Start abstractly executing the given basic block. Initializes the
     // notion of abstract state to what we believe it to be at the head
     // of the basic block, according to the basic block's data structures.
     // This method also sets cfaShouldRevisit to false.
     void beginBasicBlock(BasicBlock*);

     BasicBlock* block() const { return m_block; }

     // Finish abstractly executing a basic block. If MergeToTail or
     // MergeToSuccessors is passed, then this merges everything we have
     // learned about how the state changes during this block's execution into
     // the block's data structures.
     //
     // Returns true if the state of the block at the tail was changed,
     // and, if the state at the heads of successors was changed.
     // A true return means that you must revisit (at least) the successor
     // blocks. This also sets cfaShouldRevisit to true for basic blocks
     // that must be visited next.
     bool endBasicBlock();

     // Reset the AbstractState. This throws away any results, and at this point
     // you can safely call beginBasicBlock() on any basic block.
     void reset();

     AbstractInterpreterClobberState clobberState() const { return m_clobberState; }

     // Would have the last executed node clobbered things had we not found a way to fold it?
     bool didClobberOrFolded() const { return clobberState() != AbstractInterpreterClobberState::NotClobbered; }

     // Did the last executed node clobber the world?
     bool didClobber() const { return clobberState() == AbstractInterpreterClobberState::ClobberedStructures; }

     // Are structures currently clobbered?
     StructureClobberState structureClobberState() const { return m_structureClobberState; }

     // Is the execution state still valid? This will be false if execute() has
     // returned false previously.
     bool isValid() const { return m_isValid; }

     // Merge the abstract state stored at the first block's tail into the second
     // block's head. Returns true if the second block's state changed. If so,
     // that block must be abstractly interpreted again. This also sets
     // to->cfaShouldRevisit to true, if it returns true, or if to has not been
     // visited yet.
     bool merge(BasicBlock* from, BasicBlock* to);

     // Merge the abstract state stored at the block's tail into all of its
     // successors. Returns true if any of the successors' states changed. Note
     // that this is automatically called in endBasicBlock() if MergeMode is
     // MergeToSuccessors.
     bool mergeToSuccessors(BasicBlock*);

     void clobberStructures() { m_effectEpoch.clobber(); }

     void observeInvalidationPoint() { m_effectEpoch.observeInvalidationPoint(); }

     // Methods intended to be called from AbstractInterpreter.
     void setClobberState(AbstractInterpreterClobberState state) { m_clobberState = state; }
     void mergeClobberState(AbstractInterpreterClobberState state) { m_clobberState = mergeClobberStates(m_clobberState, state); }
     void setStructureClobberState(StructureClobberState value) { m_structureClobberState = value; }
     void setIsValid(bool isValid) { m_isValid = isValid; }
     void setBranchDirection(BranchDirection branchDirection) { m_branchDirection = branchDirection; }

     // This method is evil - it causes a huge maintenance headache and there is a gross amount of
     // code devoted to it. It would be much nicer to just always run the constant folder on each
     // block. But, the last time we did it, it was a 1% SunSpider regression:
     // https://bugs.webkit.org/show_bug.cgi?id=133947
     // So, we should probably keep this method.
     void setShouldTryConstantFolding(bool tryConstantFolding) { m_shouldTryConstantFolding = tryConstantFolding; }

     void setProofStatus(Edge& edge, ProofStatus status)
     {
         edge.setProofStatus(status);
     }

 private:
     ALWAYS_INLINE void activateVariableIfNecessary(size_t variableIndex)
     {
         if (!m_activeVariables[variableIndex])
             activateVariable(variableIndex);
     }

     void activateVariable(size_t variableIndex);
     void activateAllVariables();

     static bool mergeVariableBetweenBlocks(AbstractValue& destination, AbstractValue& source, Node* destinationNode, Node* sourceNode);

     Graph& m_graph;

     FlowMap<AbstractValue>& m_abstractValues;
     Operands<AbstractValue> m_variables;
     FastBitVector m_activeVariables;
     BasicBlock* m_block;

     bool m_shouldTryConstantFolding;

     bool m_isValid;
     AbstractInterpreterClobberState m_clobberState;
     StructureClobberState m_structureClobberState;
     AbstractValueClobberEpoch m_epochAtHead;
     AbstractValueClobberEpoch m_effectEpoch;

     BranchDirection m_branchDirection; // This is only set for blocks that end in Branch and that execute to completion (i.e. m_isValid == true).
 };

 } } // namespace JSC::DFG

 #endif // ENABLE(DFG_JIT)
	/*
	* Copyright (C) 2013-2018 Apple Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
	* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#pragma once

	#if ENABLE(DFG_JIT)

	#include "DFGAbstractInterpreterClobberState.h"
	#include "DFGAbstractValue.h"
	#include "DFGBranchDirection.h"
	#include "DFGFlowMap.h"
	#include "DFGGraph.h"
	#include "DFGNode.h"

	namespace JSC { namespace DFG {

	class InPlaceAbstractState {
	WTF_MAKE_FAST_ALLOCATED;
	public:
	InPlaceAbstractState(Graph&);

	~InPlaceAbstractState();

	explicit operator bool() const { return true; }

	void createValueForNode(NodeFlowProjection) { }

	ALWAYS_INLINE AbstractValue& fastForward(AbstractValue& value)
	{
	value.fastForwardTo(m_effectEpoch);
	return value;
	}

	ALWAYS_INLINE void fastForwardAndFilterUnproven(AbstractValue& value, SpeculatedType type)
	{
	value.fastForwardToAndFilterUnproven(m_effectEpoch, type);
	}

	ALWAYS_INLINE AbstractValue& forNodeWithoutFastForward(NodeFlowProjection node)
	{
	return m_abstractValues.at(node);
	}

	ALWAYS_INLINE AbstractValue& forNodeWithoutFastForward(Edge edge)
	{
	return forNodeWithoutFastForward(edge.node());
	}

	ALWAYS_INLINE AbstractValue& forNode(NodeFlowProjection node)
	{
	return fastForward(m_abstractValues.at(node));
	}

	ALWAYS_INLINE AbstractValue& forNode(Edge edge)
	{
	return forNode(edge.node());
	}

	ALWAYS_INLINE void clearForNode(NodeFlowProjection node)
	{
	AbstractValue& value = m_abstractValues.at(node);
	value.clear();
	value.m_effectEpoch = m_effectEpoch;
	}

	ALWAYS_INLINE void clearForNode(Edge edge)
	{
	clearForNode(edge.node());
	}

	template<typename... Arguments>
	ALWAYS_INLINE void setForNode(NodeFlowProjection node, Arguments&&... arguments)
	{
	AbstractValue& value = m_abstractValues.at(node);
	value.set(m_graph, std::forward<Arguments>(arguments)...);
	value.m_effectEpoch = m_effectEpoch;
	}

	template<typename... Arguments>
	ALWAYS_INLINE void setForNode(Edge edge, Arguments&&... arguments)
	{
	setForNode(edge.node(), std::forward<Arguments>(arguments)...);
	}

	template<typename... Arguments>
	ALWAYS_INLINE void setTypeForNode(NodeFlowProjection node, Arguments&&... arguments)
	{
	AbstractValue& value = m_abstractValues.at(node);
	value.setType(m_graph, std::forward<Arguments>(arguments)...);
	value.m_effectEpoch = m_effectEpoch;
	}

	template<typename... Arguments>
	ALWAYS_INLINE void setTypeForNode(Edge edge, Arguments&&... arguments)
	{
	setTypeForNode(edge.node(), std::forward<Arguments>(arguments)...);
	}

	template<typename... Arguments>
	ALWAYS_INLINE void setNonCellTypeForNode(NodeFlowProjection node, Arguments&&... arguments)
	{
	AbstractValue& value = m_abstractValues.at(node);
	value.setNonCellType(std::forward<Arguments>(arguments)...);
	value.m_effectEpoch = m_effectEpoch;
	}

	template<typename... Arguments>
	ALWAYS_INLINE void setNonCellTypeForNode(Edge edge, Arguments&&... arguments)
	{
	setNonCellTypeForNode(edge.node(), std::forward<Arguments>(arguments)...);
	}

	ALWAYS_INLINE void makeBytecodeTopForNode(NodeFlowProjection node)
	{
	AbstractValue& value = m_abstractValues.at(node);
	value.makeBytecodeTop();
	value.m_effectEpoch = m_effectEpoch;
	}

	ALWAYS_INLINE void makeBytecodeTopForNode(Edge edge)
	{
	makeBytecodeTopForNode(edge.node());
	}

	ALWAYS_INLINE void makeHeapTopForNode(NodeFlowProjection node)
	{
	AbstractValue& value = m_abstractValues.at(node);
	value.makeHeapTop();
	value.m_effectEpoch = m_effectEpoch;
	}

	ALWAYS_INLINE void makeHeapTopForNode(Edge edge)
	{
	makeHeapTopForNode(edge.node());
	}

	Operands<AbstractValue>& variablesForDebugging();

	unsigned size() const { return m_variables.size(); }
	unsigned numberOfArguments() const { return m_variables.numberOfArguments(); }
	unsigned numberOfLocals() const { return m_variables.numberOfLocals(); }
	unsigned numberOfTmps() const { return m_variables.numberOfTmps(); }

	AbstractValue& atIndex(size_t index)
	{
	activateVariableIfNecessary(index);
	return fastForward(m_variables[index]);
	}

	AbstractValue& operand(Operand operand)
	{
	return atIndex(m_variables.operandIndex(operand));
	}

	AbstractValue& local(size_t index)
	{
	return atIndex(m_variables.localIndex(index));
	}

	AbstractValue& argument(size_t index)
	{
	return atIndex(m_variables.argumentIndex(index));
	}

	// Call this before beginning CFA to initialize the abstract values of
	// arguments, and to indicate which blocks should be listed for CFA
	// execution.
	void initialize();

	// Start abstractly executing the given basic block. Initializes the
	// notion of abstract state to what we believe it to be at the head
	// of the basic block, according to the basic block's data structures.
	// This method also sets cfaShouldRevisit to false.
	void beginBasicBlock(BasicBlock*);

	BasicBlock* block() const { return m_block; }

	// Finish abstractly executing a basic block. If MergeToTail or
	// MergeToSuccessors is passed, then this merges everything we have
	// learned about how the state changes during this block's execution into
	// the block's data structures.
	//
	// Returns true if the state of the block at the tail was changed,
	// and, if the state at the heads of successors was changed.
	// A true return means that you must revisit (at least) the successor
	// blocks. This also sets cfaShouldRevisit to true for basic blocks
	// that must be visited next.
	bool endBasicBlock();

	// Reset the AbstractState. This throws away any results, and at this point
	// you can safely call beginBasicBlock() on any basic block.
	void reset();

	AbstractInterpreterClobberState clobberState() const { return m_clobberState; }

	// Would have the last executed node clobbered things had we not found a way to fold it?
	bool didClobberOrFolded() const { return clobberState() != AbstractInterpreterClobberState::NotClobbered; }

	// Did the last executed node clobber the world?
	bool didClobber() const { return clobberState() == AbstractInterpreterClobberState::ClobberedStructures; }

	// Are structures currently clobbered?
	StructureClobberState structureClobberState() const { return m_structureClobberState; }

	// Is the execution state still valid? This will be false if execute() has
	// returned false previously.
	bool isValid() const { return m_isValid; }

	// Merge the abstract state stored at the first block's tail into the second
	// block's head. Returns true if the second block's state changed. If so,
	// that block must be abstractly interpreted again. This also sets
	// to->cfaShouldRevisit to true, if it returns true, or if to has not been
	// visited yet.
	bool merge(BasicBlock* from, BasicBlock* to);

	// Merge the abstract state stored at the block's tail into all of its
	// successors. Returns true if any of the successors' states changed. Note
	// that this is automatically called in endBasicBlock() if MergeMode is
	// MergeToSuccessors.
	bool mergeToSuccessors(BasicBlock*);

	void clobberStructures() { m_effectEpoch.clobber(); }

	void observeInvalidationPoint() { m_effectEpoch.observeInvalidationPoint(); }

	// Methods intended to be called from AbstractInterpreter.
	void setClobberState(AbstractInterpreterClobberState state) { m_clobberState = state; }
	void mergeClobberState(AbstractInterpreterClobberState state) { m_clobberState = mergeClobberStates(m_clobberState, state); }
	void setStructureClobberState(StructureClobberState value) { m_structureClobberState = value; }
	void setIsValid(bool isValid) { m_isValid = isValid; }
	void setBranchDirection(BranchDirection branchDirection) { m_branchDirection = branchDirection; }

	// This method is evil - it causes a huge maintenance headache and there is a gross amount of
	// code devoted to it. It would be much nicer to just always run the constant folder on each
	// block. But, the last time we did it, it was a 1% SunSpider regression:
	// https://bugs.webkit.org/show_bug.cgi?id=133947
	// So, we should probably keep this method.
	void setShouldTryConstantFolding(bool tryConstantFolding) { m_shouldTryConstantFolding = tryConstantFolding; }

	void setProofStatus(Edge& edge, ProofStatus status)
	{
	edge.setProofStatus(status);
	}

	private:
	ALWAYS_INLINE void activateVariableIfNecessary(size_t variableIndex)
	{
	if (!m_activeVariables[variableIndex])
	activateVariable(variableIndex);
	}

	void activateVariable(size_t variableIndex);
	void activateAllVariables();

	static bool mergeVariableBetweenBlocks(AbstractValue& destination, AbstractValue& source, Node* destinationNode, Node* sourceNode);

	Graph& m_graph;

	FlowMap<AbstractValue>& m_abstractValues;
	Operands<AbstractValue> m_variables;
	FastBitVector m_activeVariables;
	BasicBlock* m_block;

	bool m_shouldTryConstantFolding;

	bool m_isValid;
	AbstractInterpreterClobberState m_clobberState;
	StructureClobberState m_structureClobberState;
	AbstractValueClobberEpoch m_epochAtHead;
	AbstractValueClobberEpoch m_effectEpoch;

	BranchDirection m_branchDirection; // This is only set for blocks that end in Branch and that execute to completion (i.e. m_isValid == true).
	};

	} } // namespace JSC::DFG

	#endif // ENABLE(DFG_JIT)