DFGNonSpeculativeJIT.h   [plain text]

/*
 * Copyright (C) 2011 Apple Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions
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 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
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 *
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#ifndef DFGNonSpeculativeJIT_h
#define DFGNonSpeculativeJIT_h

#if ENABLE(DFG_JIT)

#include <dfg/DFGJITCodeGenerator.h>

namespace JSC { namespace DFG {

class SpeculationCheckIndexIterator;

// === EntryLocation ===
//
// This structure describes an entry point into the non-speculative
// code path. This is used in linking bail-outs from the speculative path.
struct EntryLocation {
    EntryLocation(MacroAssembler::Label, NonSpeculativeJIT*);

    // The node this entry point corresponds to, and the label
    // marking the start of code for the given node.
    MacroAssembler::Label m_entry;
    NodeIndex m_nodeIndex;

    // For every entry point we record a map recording for every
    // machine register which, if any, values it contains. For
    // GPR registers we must also record the format of the value.
    struct RegisterInfo {
        NodeIndex nodeIndex;
        DataFormat format;
    };
    RegisterInfo m_gprInfo[GPRInfo::numberOfRegisters];
    NodeIndex m_fprInfo[FPRInfo::numberOfRegisters];
};

// === NonSpeculativeJIT ===
//
// This class is used to generate code for the non-speculative path.
// Code generation will take advantage of static information available
// in the dataflow to perform safe optimizations - for example, avoiding
// boxing numeric values between arithmetic operations, but will not
// perform any unsafe optimizations that would render the code unable
// to produce the correct results for any possible input.
class NonSpeculativeJIT : public JITCodeGenerator {
    friend struct EntryLocation;
public:
    NonSpeculativeJIT(JITCompiler& jit)
        : JITCodeGenerator(jit, false)
    {
    }

    void compile(SpeculationCheckIndexIterator&);

    typedef SegmentedVector<EntryLocation, 16> EntryLocationVector;
    EntryLocationVector& entryLocations() { return m_entryLocations; }

private:
    void compile(SpeculationCheckIndexIterator&, Node&);
    void compile(SpeculationCheckIndexIterator&, BasicBlock&);

    bool isKnownInteger(NodeIndex);
    bool isKnownNumeric(NodeIndex);

    // These methods are used when generating 'unexpected'
    // calls out from JIT code to C++ helper routines -
    // they spill all live values to the appropriate
    // slots in the RegisterFile without changing any state
    // in the GenerationInfo.
    void silentSpillGPR(VirtualRegister spillMe, GPRReg exclude = InvalidGPRReg)
    {
        GenerationInfo& info = m_generationInfo[spillMe];
        ASSERT(info.registerFormat() != DataFormatNone && info.registerFormat() != DataFormatDouble);

        if (!info.needsSpill() || (info.gpr() == exclude))
            return;

        DataFormat registerFormat = info.registerFormat();

        if (registerFormat == DataFormatInteger) {
            m_jit.orPtr(GPRInfo::tagTypeNumberRegister, info.gpr());
            m_jit.storePtr(info.gpr(), JITCompiler::addressFor(spillMe));
        } else {
            ASSERT(registerFormat & DataFormatJS || registerFormat == DataFormatCell);
            m_jit.storePtr(info.gpr(), JITCompiler::addressFor(spillMe));
        }
    }
    void silentSpillFPR(VirtualRegister spillMe, GPRReg canTrample, FPRReg exclude = InvalidFPRReg)
    {
        GenerationInfo& info = m_generationInfo[spillMe];
        ASSERT(info.registerFormat() == DataFormatDouble);

        if (!info.needsSpill() || (info.fpr() == exclude))
            return;

        boxDouble(info.fpr(), canTrample);
        m_jit.storePtr(canTrample, JITCompiler::addressFor(spillMe));
    }

    void silentFillGPR(VirtualRegister spillMe, GPRReg exclude = InvalidGPRReg)
    {
        GenerationInfo& info = m_generationInfo[spillMe];
        if (info.gpr() == exclude)
            return;

        NodeIndex nodeIndex = info.nodeIndex();
        Node& node = m_jit.graph()[nodeIndex];
        ASSERT(info.registerFormat() != DataFormatNone && info.registerFormat() != DataFormatDouble);
        DataFormat registerFormat = info.registerFormat();

        if (registerFormat == DataFormatInteger) {
            if (node.isConstant()) {
                ASSERT(isInt32Constant(nodeIndex));
                m_jit.move(Imm32(valueOfInt32Constant(nodeIndex)), info.gpr());
            } else
                m_jit.load32(JITCompiler::addressFor(spillMe), info.gpr());
            return;
        }

        if (node.isConstant())
            m_jit.move(constantAsJSValueAsImmPtr(nodeIndex), info.gpr());
        else {
            ASSERT(registerFormat & DataFormatJS || registerFormat == DataFormatCell);
            m_jit.loadPtr(JITCompiler::addressFor(spillMe), info.gpr());
        }
    }
    void silentFillFPR(VirtualRegister spillMe, GPRReg canTrample, FPRReg exclude = InvalidFPRReg)
    {
        GenerationInfo& info = m_generationInfo[spillMe];
        if (info.fpr() == exclude)
            return;

        NodeIndex nodeIndex = info.nodeIndex();
        Node& node = m_jit.graph()[nodeIndex];
        ASSERT(info.registerFormat() == DataFormatDouble);

        if (node.isConstant())
            m_jit.move(constantAsJSValueAsImmPtr(nodeIndex), info.gpr());
        else {
            m_jit.loadPtr(JITCompiler::addressFor(spillMe), canTrample);
            unboxDouble(canTrample, info.fpr());
        }
    }

    void silentSpillAllRegisters(GPRReg exclude, GPRReg preserve = InvalidGPRReg)
    {
        GPRReg canTrample = GPRInfo::regT0;
        if (preserve == GPRInfo::regT0)
            canTrample = GPRInfo::regT1;
        
        for (gpr_iterator iter = m_gprs.begin(); iter != m_gprs.end(); ++iter) {
            if (iter.name() != InvalidVirtualRegister)
                silentSpillGPR(iter.name(), exclude);
        }
        for (fpr_iterator iter = m_fprs.begin(); iter != m_fprs.end(); ++iter) {
            if (iter.name() != InvalidVirtualRegister)
                silentSpillFPR(iter.name(), canTrample);
        }
    }
    void silentSpillAllRegisters(FPRReg exclude, GPRReg preserve = InvalidGPRReg)
    {
        GPRReg canTrample = GPRInfo::regT0;
        if (preserve == GPRInfo::regT0)
            canTrample = GPRInfo::regT1;
        
        for (gpr_iterator iter = m_gprs.begin(); iter != m_gprs.end(); ++iter) {
            if (iter.name() != InvalidVirtualRegister)
                silentSpillGPR(iter.name());
        }
        for (fpr_iterator iter = m_fprs.begin(); iter != m_fprs.end(); ++iter) {
            if (iter.name() != InvalidVirtualRegister)
                silentSpillFPR(iter.name(), canTrample, exclude);
        }
    }
    void silentFillAllRegisters(GPRReg exclude)
    {
        GPRReg canTrample = GPRInfo::regT0;
        if (exclude == GPRInfo::regT0)
            canTrample = GPRInfo::regT1;
        
        for (fpr_iterator iter = m_fprs.begin(); iter != m_fprs.end(); ++iter) {
            if (iter.name() != InvalidVirtualRegister)
                silentFillFPR(iter.name(), canTrample);
        }
        for (gpr_iterator iter = m_gprs.begin(); iter != m_gprs.end(); ++iter) {
            if (iter.name() != InvalidVirtualRegister)
                silentFillGPR(iter.name(), exclude);
        }
    }
    void silentFillAllRegisters(FPRReg exclude)
    {
        GPRReg canTrample = GPRInfo::regT0;
        
        for (fpr_iterator iter = m_fprs.begin(); iter != m_fprs.end(); ++iter) {
            if (iter.name() != InvalidVirtualRegister) {
                ASSERT_UNUSED(exclude, iter.regID() != exclude);
                silentFillFPR(iter.name(), canTrample, exclude);
            }
        }
        for (gpr_iterator iter = m_gprs.begin(); iter != m_gprs.end(); ++iter) {
            if (iter.name() != InvalidVirtualRegister)
                silentFillGPR(iter.name());
        }
    }

    // These methods are used to plant calls out to C++
    // helper routines to convert between types.
    void valueToNumber(JSValueOperand&, FPRReg result);
    void valueToInt32(JSValueOperand&, GPRReg result);
    void numberToInt32(FPRReg, GPRReg result);

    // Record an entry location into the non-speculative code path;
    // for every bail-out on the speculative path we record information
    // to be able to re-enter into the non-speculative one.
    void trackEntry(MacroAssembler::Label entry)
    {
        m_entryLocations.append(EntryLocation(entry, this));
    }

    EntryLocationVector m_entryLocations;
};

} } // namespace JSC::DFG

#endif
#endif