Source/JavaScriptCore/dfg/DFGFixupPhase.cpp

/*
 * Copyright (C) 2012 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. 
 */

#include "config.h"
#include "DFGFixupPhase.h"

#if ENABLE(DFG_JIT)

#include "DFGGraph.h"
#include "DFGInsertionSet.h"
#include "DFGPhase.h"

namespace JSC { namespace DFG {

class FixupPhase : public Phase {
public:
    FixupPhase(Graph& graph)
        : Phase(graph, "fixup")
    {
    }
    
    bool run()
    {
        for (BlockIndex blockIndex = 0; blockIndex < m_graph.m_blocks.size(); ++blockIndex)
            fixupBlock(m_graph.m_blocks[blockIndex].get());
        return true;
    }

private:
    void fixupBlock(BasicBlock* block)
    {
        if (!block)
            return;
        ASSERT(block->isReachable);
        for (m_indexInBlock = 0; m_indexInBlock < block->size(); ++m_indexInBlock) {
            m_compileIndex = block->at(m_indexInBlock);
            fixupNode(m_graph[m_compileIndex]);
        }
        m_insertionSet.execute(*block);
    }
    
    void fixupNode(Node& node)
    {
        if (!node.shouldGenerate())
            return;
        
        NodeType op = node.op();

#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
        dataLog("   %s @%u: ", Graph::opName(op), m_compileIndex);
#endif
        
        switch (op) {
        case GetById: {
            if (!isInt32Speculation(m_graph[m_compileIndex].prediction()))
                break;
            if (codeBlock()->identifier(node.identifierNumber()) != globalData().propertyNames->length)
                break;
            bool isArray = isArraySpeculation(m_graph[node.child1()].prediction());
            bool isArguments = isArgumentsSpeculation(m_graph[node.child1()].prediction());
            bool isString = isStringSpeculation(m_graph[node.child1()].prediction());
            bool isInt8Array = m_graph[node.child1()].shouldSpeculateInt8Array();
            bool isInt16Array = m_graph[node.child1()].shouldSpeculateInt16Array();
            bool isInt32Array = m_graph[node.child1()].shouldSpeculateInt32Array();
            bool isUint8Array = m_graph[node.child1()].shouldSpeculateUint8Array();
            bool isUint8ClampedArray = m_graph[node.child1()].shouldSpeculateUint8ClampedArray();
            bool isUint16Array = m_graph[node.child1()].shouldSpeculateUint16Array();
            bool isUint32Array = m_graph[node.child1()].shouldSpeculateUint32Array();
            bool isFloat32Array = m_graph[node.child1()].shouldSpeculateFloat32Array();
            bool isFloat64Array = m_graph[node.child1()].shouldSpeculateFloat64Array();
            if (!isArray && !isArguments && !isString && !isInt8Array && !isInt16Array && !isInt32Array && !isUint8Array && !isUint8ClampedArray && !isUint16Array && !isUint32Array && !isFloat32Array && !isFloat64Array)
                break;
            
#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
            dataLog("  @%u -> %s", m_compileIndex, isArray ? "GetArrayLength" : "GetStringLength");
#endif
            if (isArray)
                node.setOp(GetArrayLength);
            else if (isArguments)
                node.setOp(GetArgumentsLength);
            else if (isString)
                node.setOp(GetStringLength);
            else if (isInt8Array)
                node.setOp(GetInt8ArrayLength);
            else if (isInt16Array)
                node.setOp(GetInt16ArrayLength);
            else if (isInt32Array)
                node.setOp(GetInt32ArrayLength);
            else if (isUint8Array)
                node.setOp(GetUint8ArrayLength);
            else if (isUint8ClampedArray)
                node.setOp(GetUint8ClampedArrayLength);
            else if (isUint16Array)
                node.setOp(GetUint16ArrayLength);
            else if (isUint32Array)
                node.setOp(GetUint32ArrayLength);
            else if (isFloat32Array)
                node.setOp(GetFloat32ArrayLength);
            else if (isFloat64Array)
                node.setOp(GetFloat64ArrayLength);
            else
                ASSERT_NOT_REACHED();
            // No longer MustGenerate
            ASSERT(node.flags() & NodeMustGenerate);
            node.clearFlags(NodeMustGenerate);
            m_graph.deref(m_compileIndex);
            break;
        }
        case GetIndexedPropertyStorage: {
            SpeculatedType basePrediction = m_graph[node.child2()].prediction();
            if ((!(basePrediction & SpecInt32) && basePrediction)
                || m_graph[node.child1()].shouldSpeculateArguments()
                || !isActionableArraySpeculation(m_graph[node.child1()].prediction())) {
                node.setOpAndDefaultFlags(Nop);
                m_graph.clearAndDerefChild1(node);
                m_graph.clearAndDerefChild2(node);
                m_graph.clearAndDerefChild3(node);
                node.setRefCount(0);
            }
            break;
        }
        case GetByVal:
        case StringCharAt:
        case StringCharCodeAt: {
            if (!!node.child3() && m_graph[node.child3()].op() == Nop)
                node.children.child3() = Edge();
            break;
        }
            
        case ValueToInt32: {
            if (m_graph[node.child1()].shouldSpeculateNumber()) {
                node.clearFlags(NodeMustGenerate);
                m_graph.deref(m_compileIndex);
            }
            break;
        }
            
        case BitAnd:
        case BitOr:
        case BitXor:
        case BitRShift:
        case BitLShift:
        case BitURShift: {
            fixIntEdge(node.children.child1());
            fixIntEdge(node.children.child2());
            break;
        }
            
        case CompareEq:
        case CompareLess:
        case CompareLessEq:
        case CompareGreater:
        case CompareGreaterEq:
        case CompareStrictEq: {
            if (Node::shouldSpeculateInteger(m_graph[node.child1()], m_graph[node.child2()]))
                break;
            if (!Node::shouldSpeculateNumber(m_graph[node.child1()], m_graph[node.child2()]))
                break;
            fixDoubleEdge(0);
            fixDoubleEdge(1);
            break;
        }
            
        case LogicalNot: {
            if (m_graph[node.child1()].shouldSpeculateInteger())
                break;
            if (!m_graph[node.child1()].shouldSpeculateNumber())
                break;
            fixDoubleEdge(0);
            break;
        }
            
        case Branch: {
            if (!m_graph[node.child1()].shouldSpeculateInteger()
                && m_graph[node.child1()].shouldSpeculateNumber())
                fixDoubleEdge(0);

            Node& myNode = m_graph[m_compileIndex]; // reload because the graph may have changed
            Edge logicalNotEdge = myNode.child1();
            Node& logicalNot = m_graph[logicalNotEdge];
            if (logicalNot.op() == LogicalNot
                && logicalNot.adjustedRefCount() == 1) {
                Edge newChildEdge = logicalNot.child1();
                if (m_graph[newChildEdge].hasBooleanResult()) {
                    m_graph.ref(newChildEdge);
                    m_graph.deref(logicalNotEdge);
                    myNode.children.setChild1(newChildEdge);
                    
                    BlockIndex toBeTaken = myNode.notTakenBlockIndex();
                    BlockIndex toBeNotTaken = myNode.takenBlockIndex();
                    myNode.setTakenBlockIndex(toBeTaken);
                    myNode.setNotTakenBlockIndex(toBeNotTaken);
                }
            }
            break;
        }
            
        case SetLocal: {
            if (node.variableAccessData()->isCaptured())
                break;
            if (!node.variableAccessData()->shouldUseDoubleFormat())
                break;
            fixDoubleEdge(0);
            break;
        }
            
        case ArithAdd:
        case ValueAdd: {
            if (m_graph.addShouldSpeculateInteger(node))
                break;
            if (!Node::shouldSpeculateNumber(m_graph[node.child1()], m_graph[node.child2()]))
                break;
            fixDoubleEdge(0);
            fixDoubleEdge(1);
            break;
        }
            
        case ArithSub: {
            if (m_graph.addShouldSpeculateInteger(node)
                && node.canSpeculateInteger())
                break;
            fixDoubleEdge(0);
            fixDoubleEdge(1);
            break;
        }
            
        case ArithNegate: {
            if (m_graph.negateShouldSpeculateInteger(node))
                break;
            fixDoubleEdge(0);
            break;
        }
            
        case ArithMin:
        case ArithMax:
        case ArithMod: {
            if (Node::shouldSpeculateInteger(m_graph[node.child1()], m_graph[node.child2()])
                && node.canSpeculateInteger())
                break;
            fixDoubleEdge(0);
            fixDoubleEdge(1);
            break;
        }
            
        case ArithMul: {
            if (m_graph.mulShouldSpeculateInteger(node))
                break;
            fixDoubleEdge(0);
            fixDoubleEdge(1);
            break;
        }

        case ArithDiv: {
            if (Node::shouldSpeculateInteger(m_graph[node.child1()], m_graph[node.child2()])
                && node.canSpeculateInteger()) {
                if (isX86())
                    break;
                fixDoubleEdge(0);
                fixDoubleEdge(1);
                
                Node& oldDivision = m_graph[m_compileIndex];
                
                Node newDivision = oldDivision;
                newDivision.setRefCount(2);
                newDivision.predict(SpecDouble);
                NodeIndex newDivisionIndex = m_graph.size();
                
                oldDivision.setOp(DoubleAsInt32);
                oldDivision.children.initialize(Edge(newDivisionIndex, DoubleUse), Edge(), Edge());
                
                m_graph.append(newDivision);
                m_insertionSet.append(m_indexInBlock, newDivisionIndex);
                
                break;
            }
            fixDoubleEdge(0);
            fixDoubleEdge(1);
            break;
        }
            
        case ArithAbs: {
            if (m_graph[node.child1()].shouldSpeculateInteger()
                && node.canSpeculateInteger())
                break;
            fixDoubleEdge(0);
            break;
        }
            
        case ArithSqrt: {
            fixDoubleEdge(0);
            break;
        }
            
        case PutByVal: {
            if (!m_graph[node.child1()].prediction() || !m_graph[node.child2()].prediction())
                break;
            if (!m_graph[node.child2()].shouldSpeculateInteger())
                break;
            if (isActionableIntMutableArraySpeculation(m_graph[node.child1()].prediction())) {
                if (m_graph[node.child3()].isConstant())
                    break;
                if (m_graph[node.child3()].shouldSpeculateInteger())
                    break;
                fixDoubleEdge(2);
                break;
            }
            if (isActionableFloatMutableArraySpeculation(m_graph[node.child1()].prediction())) {
                fixDoubleEdge(2);
                break;
            }
            break;
        }
            
        default:
            break;
        }

#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
        if (!(node.flags() & NodeHasVarArgs)) {
            dataLog("new children: ");
            node.dumpChildren(WTF::dataFile());
        }
        dataLog("\n");
#endif
    }
    
    void fixIntEdge(Edge& edge)
    {
        Node& node = m_graph[edge];
        if (node.op() != ValueToInt32)
            return;
        
        if (!m_graph[node.child1()].shouldSpeculateInteger())
            return;
        
        Edge oldEdge = edge;
        Edge newEdge = node.child1();
        
        m_graph.ref(newEdge);
        m_graph.deref(oldEdge);
        
        edge = newEdge;
    }
    
    void fixDoubleEdge(unsigned childIndex)
    {
        Node& source = m_graph[m_compileIndex];
        Edge& edge = source.children.child(childIndex);
        
        if (!m_graph[edge].shouldSpeculateInteger()) {
            edge.setUseKind(DoubleUse);
            return;
        }
        
        NodeIndex resultIndex = (NodeIndex)m_graph.size();
        
#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
        dataLog("(replacing @%u->@%u with @%u->@%u) ",
                m_compileIndex, edge.index(), m_compileIndex, resultIndex);
#endif
        
        // Fix the edge up here because it's a reference that will be clobbered by
        // the append() below.
        NodeIndex oldIndex = edge.index();
        edge = Edge(resultIndex, DoubleUse);

        m_graph.append(Node(Int32ToDouble, source.codeOrigin, oldIndex));
        m_insertionSet.append(m_indexInBlock, resultIndex);
        
        Node& int32ToDouble = m_graph[resultIndex];
        int32ToDouble.predict(SpecDouble);
        int32ToDouble.ref();
    }
    
    unsigned m_indexInBlock;
    NodeIndex m_compileIndex;
    InsertionSet<NodeIndex> m_insertionSet;
};
    
bool performFixup(Graph& graph)
{
    return runPhase<FixupPhase>(graph);
}

} } // namespace JSC::DFG

#endif // ENABLE(DFG_JIT)