src/third_party/mozjs-45/js/src/jit/mips64/Assembler-mips64.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * 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_mips64_Assembler_mips64_h
#define jit_mips64_Assembler_mips64_h

#include "jit/mips-shared/Assembler-mips-shared.h"

#include "jit/mips64/Architecture-mips64.h"

namespace js {
namespace jit {

static MOZ_CONSTEXPR_VAR Register CallTempReg4 = a4;
static MOZ_CONSTEXPR_VAR Register CallTempReg5 = a5;

static MOZ_CONSTEXPR_VAR Register CallTempNonArgRegs[] = { t0, t1, t2, t3 };
static const uint32_t NumCallTempNonArgRegs = mozilla::ArrayLength(CallTempNonArgRegs);

class ABIArgGenerator
{
    unsigned usedArgSlots_;
    bool firstArgFloat;
    ABIArg current_;

  public:
    ABIArgGenerator();
    ABIArg next(MIRType argType);
    ABIArg& current() { return current_; }

    uint32_t stackBytesConsumedSoFar() const {
        if (usedArgSlots_ <= 8)
            return 0;

        return (usedArgSlots_ - 8) * sizeof(int64_t);
    }

    static const Register NonArgReturnReg0;
    static const Register NonArgReturnReg1;
    static const Register NonArg_VolatileReg;
    static const Register NonReturn_VolatileReg0;
    static const Register NonReturn_VolatileReg1;
};

static MOZ_CONSTEXPR_VAR Register JSReturnReg = v1;
static MOZ_CONSTEXPR_VAR Register JSReturnReg_Type = JSReturnReg;
static MOZ_CONSTEXPR_VAR Register JSReturnReg_Data = JSReturnReg;
static MOZ_CONSTEXPR_VAR FloatRegister ReturnFloat32Reg = { FloatRegisters::f0, FloatRegisters::Single };
static MOZ_CONSTEXPR_VAR FloatRegister ReturnDoubleReg = { FloatRegisters::f0, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister ScratchFloat32Reg = { FloatRegisters::f23, FloatRegisters::Single };
static MOZ_CONSTEXPR_VAR FloatRegister ScratchDoubleReg = { FloatRegisters::f23, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister SecondScratchFloat32Reg = { FloatRegisters::f21, FloatRegisters::Single };
static MOZ_CONSTEXPR_VAR FloatRegister SecondScratchDoubleReg = { FloatRegisters::f21, FloatRegisters::Double };

// Registers used in the GenerateFFIIonExit Disable Activation block.
// None of these may be the second scratch register (t8).
static MOZ_CONSTEXPR_VAR Register AsmJSIonExitRegReturnData = JSReturnReg_Data;
static MOZ_CONSTEXPR_VAR Register AsmJSIonExitRegReturnType = JSReturnReg_Type;

static MOZ_CONSTEXPR_VAR FloatRegister f0  = { FloatRegisters::f0, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f1  = { FloatRegisters::f1, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f2  = { FloatRegisters::f2, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f3  = { FloatRegisters::f3, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f4  = { FloatRegisters::f4, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f5  = { FloatRegisters::f5, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f6  = { FloatRegisters::f6, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f7  = { FloatRegisters::f7, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f8  = { FloatRegisters::f8, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f9  = { FloatRegisters::f9, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f10 = { FloatRegisters::f10, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f11 = { FloatRegisters::f11, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f12 = { FloatRegisters::f12, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f13 = { FloatRegisters::f13, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f14 = { FloatRegisters::f14, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f15 = { FloatRegisters::f15, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f16 = { FloatRegisters::f16, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f17 = { FloatRegisters::f17, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f18 = { FloatRegisters::f18, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f19 = { FloatRegisters::f19, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f20 = { FloatRegisters::f20, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f21 = { FloatRegisters::f21, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f22 = { FloatRegisters::f22, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f23 = { FloatRegisters::f23, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f24 = { FloatRegisters::f24, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f25 = { FloatRegisters::f25, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f26 = { FloatRegisters::f26, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f27 = { FloatRegisters::f27, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f28 = { FloatRegisters::f28, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f29 = { FloatRegisters::f29, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f30 = { FloatRegisters::f30, FloatRegisters::Double };
static MOZ_CONSTEXPR_VAR FloatRegister f31 = { FloatRegisters::f31, FloatRegisters::Double };

// MIPS64 CPUs can only load multibyte data that is "naturally"
// eight-byte-aligned, sp register should be sixteen-byte-aligned.
static MOZ_CONSTEXPR_VAR uint32_t ABIStackAlignment = 16;
static MOZ_CONSTEXPR_VAR uint32_t JitStackAlignment = 16;

static MOZ_CONSTEXPR_VAR uint32_t JitStackValueAlignment = JitStackAlignment / sizeof(Value);
static_assert(JitStackAlignment % sizeof(Value) == 0 && JitStackValueAlignment >= 1,
  "Stack alignment should be a non-zero multiple of sizeof(Value)");

// TODO this is just a filler to prevent a build failure. The MIPS SIMD
// alignment requirements still need to be explored.
// TODO Copy the static_asserts from x64/x86 assembler files.
static MOZ_CONSTEXPR_VAR uint32_t SimdMemoryAlignment = 16;

static MOZ_CONSTEXPR_VAR uint32_t AsmJSStackAlignment = SimdMemoryAlignment;

static MOZ_CONSTEXPR_VAR Scale ScalePointer = TimesEight;

class Assembler : public AssemblerMIPSShared
{
  public:
    Assembler()
      : AssemblerMIPSShared()
    { }

    // MacroAssemblers hold onto gcthings, so they are traced by the GC.
    void trace(JSTracer* trc);

    static uintptr_t GetPointer(uint8_t*);

    using AssemblerMIPSShared::bind;

    void bind(RepatchLabel* label);
    void Bind(uint8_t* rawCode, CodeOffset* label, const void* address);

    static void TraceJumpRelocations(JSTracer* trc, JitCode* code, CompactBufferReader& reader);
    static void TraceDataRelocations(JSTracer* trc, JitCode* code, CompactBufferReader& reader);

    void bind(InstImm* inst, uintptr_t branch, uintptr_t target);

    // Copy the assembly code to the given buffer, and perform any pending
    // relocations relying on the target address.
    void executableCopy(uint8_t* buffer);

    static uint32_t PatchWrite_NearCallSize();

    static uint64_t ExtractLoad64Value(Instruction* inst0);
    static void UpdateLoad64Value(Instruction* inst0, uint64_t value);
    static void WriteLoad64Instructions(Instruction* inst0, Register reg, uint64_t value);


    static void PatchWrite_NearCall(CodeLocationLabel start, CodeLocationLabel toCall);
    static void PatchDataWithValueCheck(CodeLocationLabel label, ImmPtr newValue,
                                        ImmPtr expectedValue);
    static void PatchDataWithValueCheck(CodeLocationLabel label, PatchedImmPtr newValue,
                                        PatchedImmPtr expectedValue);

    static void PatchInstructionImmediate(uint8_t* code, PatchedImmPtr imm);
    static uint64_t ExtractInstructionImmediate(uint8_t* code);

    static void ToggleCall(CodeLocationLabel inst_, bool enabled);

    static void UpdateBoundsCheck(uint64_t logHeapSize, Instruction* inst);
}; // Assembler

static const uint32_t NumIntArgRegs = 8;
static const uint32_t NumFloatArgRegs = NumIntArgRegs;

static inline bool
GetIntArgReg(uint32_t usedArgSlots, Register* out)
{
    if (usedArgSlots < NumIntArgRegs) {
        *out = Register::FromCode(a0.code() + usedArgSlots);
        return true;
    }
    return false;
}

static inline bool
GetFloatArgReg(uint32_t usedArgSlots, FloatRegister* out)
{
    if (usedArgSlots < NumFloatArgRegs) {
        *out = FloatRegister::FromCode(f12.code() + usedArgSlots);
        return true;
    }
    return false;
}

// Get a register in which we plan to put a quantity that will be used as an
// integer argument. This differs from GetIntArgReg in that if we have no more
// actual argument registers to use we will fall back on using whatever
// CallTempReg* don't overlap the argument registers, and only fail once those
// run out too.
static inline bool
GetTempRegForIntArg(uint32_t usedIntArgs, uint32_t usedFloatArgs, Register* out)
{
    // NOTE: We can't properly determine which regs are used if there are
    // float arguments. If this is needed, we will have to guess.
    MOZ_ASSERT(usedFloatArgs == 0);

    if (GetIntArgReg(usedIntArgs, out))
        return true;
    // Unfortunately, we have to assume things about the point at which
    // GetIntArgReg returns false, because we need to know how many registers it
    // can allocate.
    usedIntArgs -= NumIntArgRegs;
    if (usedIntArgs >= NumCallTempNonArgRegs)
        return false;
    *out = CallTempNonArgRegs[usedIntArgs];
    return true;
}

static inline uint32_t
GetArgStackDisp(uint32_t usedArgSlots)
{
    MOZ_ASSERT(usedArgSlots >= NumIntArgRegs);
    return (usedArgSlots - NumIntArgRegs) * sizeof(int64_t);
}

} // namespace jit
} // namespace js

#endif /* jit_mips64_Assembler_mips64_h */