path: root/js/src/jit/Recover.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef jit_Recover_h
#define jit_Recover_h

#include "mozilla/Attributes.h"

#include "jsarray.h"

#include "jit/MIR.h"
#include "jit/Snapshots.h"

struct JSContext;

namespace js {
namespace jit {

// This file contains all recover instructions.
//
// A recover instruction is an equivalent of a MIR instruction which is executed
// before the reconstruction of a baseline frame. Recover instructions are used
// by resume points to fill the value which are not produced by the code
// compiled by IonMonkey. For example, if a value is optimized away by
// IonMonkey, but required by Baseline, then we should have a recover
// instruction to fill the missing baseline frame slot.
//
// Recover instructions are executed either during a bailout, or under a call
// when the stack frame is introspected. If the stack is introspected, then any
// use of recover instruction must lead to an invalidation of the code.
//
// For each MIR instruction where |canRecoverOnBailout| might return true, we
// have a RInstruction of the same name.
//
// Recover instructions are encoded by the code generator into a compact buffer
// (RecoverWriter). The MIR instruction method |writeRecoverData| should write a
// tag in the |CompactBufferWriter| which is used by
// |RInstruction::readRecoverData| to dispatch to the right Recover
// instruction. Then |writeRecoverData| writes any local fields which are
// necessary for the execution of the |recover| method. These fields are decoded
// by the Recover instruction constructor which has a |CompactBufferReader| as
// argument. The constructor of the Recover instruction should follow the same
// sequence as the |writeRecoverData| method of the MIR instruction.
//
// Recover instructions are decoded by the |SnapshotIterator| (RecoverReader),
// which is given as argument of the |recover| methods, in order to read the
// operands.  The number of operands read should be the same as the result of
// |numOperands|, which corresponds to the number of operands of the MIR
// instruction.  Operands should be decoded in the same order as the operands of
// the MIR instruction.
//
// The result of the |recover| method should either be a failure, or a value
// stored on the |SnapshotIterator|, by using the |storeInstructionResult|
// method.

#define RECOVER_OPCODE_LIST(_)                  \
    _(ResumePoint)                              \
    _(BitNot)                                   \
    _(BitAnd)                                   \
    _(BitOr)                                    \
    _(BitXor)                                   \
    _(Lsh)                                      \
    _(Rsh)                                      \
    _(Ursh)                                     \
    _(SignExtend)                               \
    _(Add)                                      \
    _(Sub)                                      \
    _(Mul)                                      \
    _(Div)                                      \
    _(Mod)                                      \
    _(Not)                                      \
    _(Concat)                                   \
    _(StringLength)                             \
    _(ArgumentsLength)                          \
    _(Floor)                                    \
    _(Ceil)                                     \
    _(Round)                                    \
    _(CharCodeAt)                               \
    _(FromCharCode)                             \
    _(Pow)                                      \
    _(PowHalf)                                  \
    _(MinMax)                                   \
    _(Abs)                                      \
    _(Sqrt)                                     \
    _(Atan2)                                    \
    _(Hypot)                                    \
    _(MathFunction)                             \
    _(Random)                                   \
    _(StringSplit)                              \
    _(NaNToZero)                                \
    _(RegExpMatcher)                            \
    _(RegExpSearcher)                           \
    _(RegExpTester)                             \
    _(StringReplace)                            \
    _(TypeOf)                                   \
    _(ToDouble)                                 \
    _(ToFloat32)                                \
    _(TruncateToInt32)                          \
    _(NewObject)                                \
    _(NewTypedArray)                            \
    _(NewArray)                                 \
    _(NewDerivedTypedObject)                    \
    _(CreateThisWithTemplate)                   \
    _(Lambda)                                   \
    _(SimdBox)                                  \
    _(ObjectState)                              \
    _(ArrayState)                               \
    _(AtomicIsLockFree)                         \
    _(AssertRecoveredOnBailout)

class RResumePoint;
class SnapshotIterator;

class RInstruction
{
  public:
    enum Opcode
    {
#   define DEFINE_OPCODES_(op) Recover_##op,
        RECOVER_OPCODE_LIST(DEFINE_OPCODES_)
#   undef DEFINE_OPCODES_
        Recover_Invalid
    };

    virtual Opcode opcode() const = 0;

    // As opposed to the MIR, there is no need to add more methods as every
    // other instruction is well abstracted under the "recover" method.
    bool isResumePoint() const {
        return opcode() == Recover_ResumePoint;
    }
    inline const RResumePoint* toResumePoint() const;

    // Number of allocations which are encoded in the Snapshot for recovering
    // the current instruction.
    virtual uint32_t numOperands() const = 0;

    // Function used to recover the value computed by this instruction. This
    // function reads its arguments from the allocations listed on the snapshot
    // iterator and stores its returned value on the snapshot iterator too.
    virtual MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const = 0;

    // Decode an RInstruction on top of the reserved storage space, based on the
    // tag written by the writeRecoverData function of the corresponding MIR
    // instruction.
    static void readRecoverData(CompactBufferReader& reader, RInstructionStorage* raw);
};

#define RINSTRUCTION_HEADER_(op)                                        \
  private:                                                              \
    friend class RInstruction;                                          \
    explicit R##op(CompactBufferReader& reader);                        \
                                                                        \
  public:                                                               \
    Opcode opcode() const {                                             \
        return RInstruction::Recover_##op;                              \
    }

#define RINSTRUCTION_HEADER_NUM_OP_MAIN(op, numOp)                      \
    RINSTRUCTION_HEADER_(op)                                            \
    virtual uint32_t numOperands() const {                              \
        return numOp;                                                   \
    }

#ifdef DEBUG
# define RINSTRUCTION_HEADER_NUM_OP_(op, numOp)                         \
    RINSTRUCTION_HEADER_NUM_OP_MAIN(op, numOp)                          \
    static_assert(M##op::staticNumOperands == numOp, "The recover instructions's numOperands should equal to the MIR's numOperands");
#else
# define RINSTRUCTION_HEADER_NUM_OP_(op, numOp)                         \
    RINSTRUCTION_HEADER_NUM_OP_MAIN(op, numOp)
#endif

class RResumePoint final : public RInstruction
{
  private:
    uint32_t pcOffset_;           // Offset from script->code.
    uint32_t numOperands_;        // Number of slots.

  public:
    RINSTRUCTION_HEADER_(ResumePoint)

    uint32_t pcOffset() const {
        return pcOffset_;
    }
    virtual uint32_t numOperands() const {
        return numOperands_;
    }
    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RBitNot final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(BitNot, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RBitAnd final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(BitAnd, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RBitOr final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(BitOr, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RBitXor final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(BitXor, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RLsh final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Lsh, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RRsh final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Rsh, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RUrsh final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Ursh, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RSignExtend final : public RInstruction
{
  private:
    uint8_t mode_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(SignExtend, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RAdd final : public RInstruction
{
  private:
    bool isFloatOperation_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(Add, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RSub final : public RInstruction
{
  private:
    bool isFloatOperation_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(Sub, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RMul final : public RInstruction
{
  private:
    bool isFloatOperation_;
    uint8_t mode_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(Mul, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RDiv final : public RInstruction
{
  private:
    bool isFloatOperation_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(Div, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RMod final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Mod, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RNot final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Not, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RConcat final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Concat, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RStringLength final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(StringLength, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RArgumentsLength final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(ArgumentsLength, 0)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};


class RFloor final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Floor, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RCeil final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Ceil, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RRound final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Round, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RCharCodeAt final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(CharCodeAt, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RFromCharCode final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(FromCharCode, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RPow final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Pow, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RPowHalf final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(PowHalf, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RMinMax final : public RInstruction
{
  private:
    bool isMax_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(MinMax, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RAbs final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Abs, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RSqrt final : public RInstruction
{
  private:
    bool isFloatOperation_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(Sqrt, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RAtan2 final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Atan2, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RHypot final : public RInstruction
{
   private:
     uint32_t numOperands_;

   public:
     RINSTRUCTION_HEADER_(Hypot)

     virtual uint32_t numOperands() const {
         return numOperands_;
     }

     MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RMathFunction final : public RInstruction
{
  private:
    uint8_t function_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(MathFunction, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RRandom final : public RInstruction
{
    RINSTRUCTION_HEADER_NUM_OP_(Random, 0)
  public:
    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RStringSplit final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(StringSplit, 3)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RNaNToZero final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(NaNToZero, 1);

    bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RRegExpMatcher final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(RegExpMatcher, 3)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RRegExpSearcher final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(RegExpSearcher, 3)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RRegExpTester final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(RegExpTester, 3)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RStringReplace final : public RInstruction
{
  private:
    bool isFlatReplacement_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(StringReplace, 3)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RTypeOf final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(TypeOf, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RToDouble final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(ToDouble, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RToFloat32 final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(ToFloat32, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RTruncateToInt32 final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(TruncateToInt32, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RNewObject final : public RInstruction
{
  private:
    MNewObject::Mode mode_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(NewObject, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RNewTypedArray final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(NewTypedArray, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RNewArray final : public RInstruction
{
  private:
    uint32_t count_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(NewArray, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RNewDerivedTypedObject final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(NewDerivedTypedObject, 3)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RCreateThisWithTemplate final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(CreateThisWithTemplate, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RLambda final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(Lambda, 2)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RSimdBox final : public RInstruction
{
  private:
    uint8_t type_;

  public:
    RINSTRUCTION_HEADER_NUM_OP_(SimdBox, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RObjectState final : public RInstruction
{
  private:
    uint32_t numSlots_;        // Number of slots.

  public:
    RINSTRUCTION_HEADER_(ObjectState)

    uint32_t numSlots() const {
        return numSlots_;
    }
    virtual uint32_t numOperands() const {
        // +1 for the object.
        return numSlots() + 1;
    }

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RArrayState final : public RInstruction
{
  private:
    uint32_t numElements_;

  public:
    RINSTRUCTION_HEADER_(ArrayState)

    uint32_t numElements() const {
        return numElements_;
    }
    virtual uint32_t numOperands() const {
        // +1 for the array.
        // +1 for the initalized length.
        return numElements() + 2;
    }

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RAtomicIsLockFree final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(AtomicIsLockFree, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

class RAssertRecoveredOnBailout final : public RInstruction
{
  public:
    RINSTRUCTION_HEADER_NUM_OP_(AssertRecoveredOnBailout, 1)

    MOZ_MUST_USE bool recover(JSContext* cx, SnapshotIterator& iter) const;
};

#undef RINSTRUCTION_HEADER_
#undef RINSTRUCTION_HEADER_NUM_OP_
#undef RINSTRUCTION_HEADER_NUM_OP_MAIN

const RResumePoint*
RInstruction::toResumePoint() const
{
    MOZ_ASSERT(isResumePoint());
    return static_cast<const RResumePoint*>(this);
}

} // namespace jit
} // namespace js

#endif /* jit_Recover_h */