// Copyright (c) 1994-2006 Sun Microsystems 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:
//
// - Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// - Redistribution 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.
//
// - Neither the name of Sun Microsystems or the names of contributors may
// be used to endorse or promote products derived from this software without
// specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT OWNER 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.
// The original source code covered by the above license above has been
// modified significantly by Google Inc.
// Copyright 2011 the V8 project authors. All rights reserved.
// A lightweight X64 Assembler.
#ifndef V8_X64_ASSEMBLER_X64_H_
#define V8_X64_ASSEMBLER_X64_H_
#include "serialize.h"
namespace v8 {
namespace internal {
// Utility functions
// Test whether a 64-bit value is in a specific range.
static inline bool is_uint32(int64_t x) {
static const uint64_t kMaxUInt32 = V8_UINT64_C(0xffffffff);
return static_cast<uint64_t>(x) <= kMaxUInt32;
}
static inline bool is_int32(int64_t x) {
static const int64_t kMinInt32 = -V8_INT64_C(0x80000000);
return is_uint32(x - kMinInt32);
}
static inline bool uint_is_int32(uint64_t x) {
static const uint64_t kMaxInt32 = V8_UINT64_C(0x7fffffff);
return x <= kMaxInt32;
}
static inline bool is_uint32(uint64_t x) {
static const uint64_t kMaxUInt32 = V8_UINT64_C(0xffffffff);
return x <= kMaxUInt32;
}
// CPU Registers.
//
// 1) We would prefer to use an enum, but enum values are assignment-
// compatible with int, which has caused code-generation bugs.
//
// 2) We would prefer to use a class instead of a struct but we don't like
// the register initialization to depend on the particular initialization
// order (which appears to be different on OS X, Linux, and Windows for the
// installed versions of C++ we tried). Using a struct permits C-style
// "initialization". Also, the Register objects cannot be const as this
// forces initialization stubs in MSVC, making us dependent on initialization
// order.
//
// 3) By not using an enum, we are possibly preventing the compiler from
// doing certain constant folds, which may significantly reduce the
// code generated for some assembly instructions (because they boil down
// to a few constants). If this is a problem, we could change the code
// such that we use an enum in optimized mode, and the struct in debug
// mode. This way we get the compile-time error checking in debug mode
// and best performance in optimized code.
//
struct Register {
// The non-allocatable registers are:
// rsp - stack pointer
// rbp - frame pointer
// rsi - context register
// r10 - fixed scratch register
// r12 - smi constant register
// r13 - root register
static const int kNumRegisters = 16;
static const int kNumAllocatableRegisters = 10;
static int ToAllocationIndex(Register reg) {
return kAllocationIndexByRegisterCode[reg.code()];
}
static Register FromAllocationIndex(int index) {
ASSERT(index >= 0 && index < kNumAllocatableRegisters);
Register result = { kRegisterCodeByAllocationIndex[index] };
return result;
}
static const char* AllocationIndexToString(int index) {
ASSERT(index >= 0 && index < kNumAllocatableRegisters);
const char* const names[] = {
"rax",
"rbx",
"rdx",
"rcx",
"rdi",
"r8",
"r9",
"r11",
"r14",
"r15"
};
return names[index];
}
static Register toRegister(int code) {
Register r = { code };
return r;
}
bool is_valid() const { return 0 <= code_ && code_ < kNumRegisters; }
bool is(Register reg) const { return code_ == reg.code_; }
int code() const {
ASSERT(is_valid());
return code_;
}
int bit() const {
return 1 << code_;
}
// Return the high bit of the register code as a 0 or 1. Used often
// when constructing the REX prefix byte.
int high_bit() const {
return code_ >> 3;
}
// Return the 3 low bits of the register code. Used when encoding registers
// in modR/M, SIB, and opcode bytes.
int low_bits() const {
return code_ & 0x7;
}
// Unfortunately we can't make this private in a struct when initializing
// by assignment.
int code_;
private:
static const int kRegisterCodeByAllocationIndex[kNumAllocatableRegisters];
static const int kAllocationIndexByRegisterCode[kNumRegisters];
};
const Register rax = { 0 };
const Register rcx = { 1 };
const Register rdx = { 2 };
const Register rbx = { 3 };
const Register rsp = { 4 };
const Register rbp = { 5 };
const Register rsi = { 6 };
const Register rdi = { 7 };
const Register r8 = { 8 };
const Register r9 = { 9 };
const Register r10 = { 10 };
const Register r11 = { 11 };
const Register r12 = { 12 };
const Register r13 = { 13 };
const Register r14 = { 14 };
const Register r15 = { 15 };
const Register no_reg = { -1 };
struct XMMRegister {
static const int kNumRegisters = 16;
static const int kNumAllocatableRegisters = 15;
static int ToAllocationIndex(XMMRegister reg) {
ASSERT(reg.code() != 0);
return reg.code() - 1;
}
static XMMRegister FromAllocationIndex(int index) {
ASSERT(0 <= index && index < kNumAllocatableRegisters);
XMMRegister result = { index + 1 };
return result;
}
static const char* AllocationIndexToString(int index) {
ASSERT(index >= 0 && index < kNumAllocatableRegisters);
const char* const names[] = {
"xmm1",
"xmm2",
"xmm3",
"xmm4",
"xmm5",
"xmm6",
"xmm7",
"xmm8",
"xmm9",
"xmm10",
"xmm11",
"xmm12",
"xmm13",
"xmm14",
"xmm15"
};
return names[index];
}
bool is_valid() const { return 0 <= code_ && code_ < kNumRegisters; }
bool is(XMMRegister reg) const { return code_ == reg.code_; }
int code() const {
ASSERT(is_valid());
return code_;
}
// Return the high bit of the register code as a 0 or 1. Used often
// when constructing the REX prefix byte.
int high_bit() const {
return code_ >> 3;
}
// Return the 3 low bits of the register code. Used when encoding registers
// in modR/M, SIB, and opcode bytes.
int low_bits() const {
return code_ & 0x7;
}
int code_;
};
const XMMRegister xmm0 = { 0 };
const XMMRegister xmm1 = { 1 };
const XMMRegister xmm2 = { 2 };
const XMMRegister xmm3 = { 3 };
const XMMRegister xmm4 = { 4 };
const XMMRegister xmm5 = { 5 };
const XMMRegister xmm6 = { 6 };
const XMMRegister xmm7 = { 7 };
const XMMRegister xmm8 = { 8 };
const XMMRegister xmm9 = { 9 };
const XMMRegister xmm10 = { 10 };
const XMMRegister xmm11 = { 11 };
const XMMRegister xmm12 = { 12 };
const XMMRegister xmm13 = { 13 };
const XMMRegister xmm14 = { 14 };
const XMMRegister xmm15 = { 15 };
typedef XMMRegister DoubleRegister;
enum Condition {
// any value < 0 is considered no_condition
no_condition = -1,
overflow = 0,
no_overflow = 1,
below = 2,
above_equal = 3,
equal = 4,
not_equal = 5,
below_equal = 6,
above = 7,
negative = 8,
positive = 9,
parity_even = 10,
parity_odd = 11,
less = 12,
greater_equal = 13,
less_equal = 14,
greater = 15,
// Fake conditions that are handled by the
// opcodes using them.
always = 16,
never = 17,
// aliases
carry = below,
not_carry = above_equal,
zero = equal,
not_zero = not_equal,
sign = negative,
not_sign = positive,
last_condition = greater
};
// Returns the equivalent of !cc.
// Negation of the default no_condition (-1) results in a non-default
// no_condition value (-2). As long as tests for no_condition check
// for condition < 0, this will work as expected.
inline Condition NegateCondition(Condition cc) {
return static_cast<Condition>(cc ^ 1);
}
// Corresponds to transposing the operands of a comparison.
inline Condition ReverseCondition(Condition cc) {
switch (cc) {
case below:
return above;
case above:
return below;
case above_equal:
return below_equal;
case below_equal:
return above_equal;
case less:
return greater;
case greater:
return less;
case greater_equal:
return less_equal;
case less_equal:
return greater_equal;
default:
return cc;
};
}
enum Hint {
no_hint = 0,
not_taken = 0x2e,
taken = 0x3e
};
// The result of negating a hint is as if the corresponding condition
// were negated by NegateCondition. That is, no_hint is mapped to
// itself and not_taken and taken are mapped to each other.
inline Hint NegateHint(Hint hint) {
return (hint == no_hint)
? no_hint
: ((hint == not_taken) ? taken : not_taken);
}
// -----------------------------------------------------------------------------
// Machine instruction Immediates
class Immediate BASE_EMBEDDED {
public:
explicit Immediate(int32_t value) : value_(value) {}
private:
int32_t value_;
friend class Assembler;
};
// -----------------------------------------------------------------------------
// Machine instruction Operands
enum ScaleFactor {
times_1 = 0,
times_2 = 1,
times_4 = 2,
times_8 = 3,
times_int_size = times_4,
times_pointer_size = times_8
};
class Operand BASE_EMBEDDED {
public:
// [base + disp/r]
Operand(Register base, int32_t disp);
// [base + index*scale + disp/r]
Operand(Register base,
Register index,
ScaleFactor scale,
int32_t disp);
// [index*scale + disp/r]
Operand(Register index,
ScaleFactor scale,
int32_t disp);
// Offset from existing memory operand.
// Offset is added to existing displacement as 32-bit signed values and
// this must not overflow.
Operand(const Operand& base, int32_t offset);
// Checks whether either base or index register is the given register.
// Does not check the "reg" part of the Operand.
bool AddressUsesRegister(Register reg) const;
// Queries related to the size of the generated instruction.
// Whether the generated instruction will have a REX prefix.
bool requires_rex() const { return rex_ != 0; }
// Size of the ModR/M, SIB and displacement parts of the generated
// instruction.
int operand_size() const { return len_; }
private:
byte rex_;
byte buf_[6];
// The number of bytes of buf_ in use.
byte len_;
// Set the ModR/M byte without an encoded 'reg' register. The
// register is encoded later as part of the emit_operand operation.
// set_modrm can be called before or after set_sib and set_disp*.
inline void set_modrm(int mod, Register rm);
// Set the SIB byte if one is needed. Sets the length to 2 rather than 1.
inline void set_sib(ScaleFactor scale, Register index, Register base);
// Adds operand displacement fields (offsets added to the memory address).
// Needs to be called after set_sib, not before it.
inline void set_disp8(int disp);
inline void set_disp32(int disp);
friend class Assembler;
};
// CpuFeatures keeps track of which features are supported by the target CPU.
// Supported features must be enabled by a Scope before use.
// Example:
// if (CpuFeatures::IsSupported(SSE3)) {
// CpuFeatures::Scope fscope(SSE3);
// // Generate SSE3 floating point code.
// } else {
// // Generate standard x87 or SSE2 floating point code.
// }
class CpuFeatures : public AllStatic {
public:
// Detect features of the target CPU. Set safe defaults if the serializer
// is enabled (snapshots must be portable).
static void Probe();
// Check whether a feature is supported by the target CPU.
static bool IsSupported(CpuFeature f) {
ASSERT(initialized_);
if (f == SSE2 && !FLAG_enable_sse2) return false;
if (f == SSE3 && !FLAG_enable_sse3) return false;
if (f == CMOV && !FLAG_enable_cmov) return false;
if (f == RDTSC && !FLAG_enable_rdtsc) return false;
if (f == SAHF && !FLAG_enable_sahf) return false;
return (supported_ & (V8_UINT64_C(1) << f)) != 0;
}
#ifdef DEBUG
// Check whether a feature is currently enabled.
static bool IsEnabled(CpuFeature f) {
ASSERT(initialized_);
Isolate* isolate = Isolate::UncheckedCurrent();
if (isolate == NULL) {
// When no isolate is available, work as if we're running in
// release mode.
return IsSupported(f);
}
uint64_t enabled = isolate->enabled_cpu_features();
return (enabled & (V8_UINT64_C(1) << f)) != 0;
}
#endif
// Enable a specified feature within a scope.
class Scope BASE_EMBEDDED {
#ifdef DEBUG
public:
explicit Scope(CpuFeature f) {
uint64_t mask = V8_UINT64_C(1) << f;
ASSERT(CpuFeatures::IsSupported(f));
ASSERT(!Serializer::enabled() ||
(CpuFeatures::found_by_runtime_probing_ & mask) == 0);
isolate_ = Isolate::UncheckedCurrent();
old_enabled_ = 0;
if (isolate_ != NULL) {
old_enabled_ = isolate_->enabled_cpu_features();
isolate_->set_enabled_cpu_features(old_enabled_ | mask);
}
}
~Scope() {
ASSERT_EQ(Isolate::UncheckedCurrent(), isolate_);
if (isolate_ != NULL) {
isolate_->set_enabled_cpu_features(old_enabled_);
}
}
private:
Isolate* isolate_;
uint64_t old_enabled_;
#else
public:
explicit Scope(CpuFeature f) {}
#endif
};
private:
// Safe defaults include SSE2 and CMOV for X64. It is always available, if
// anyone checks, but they shouldn't need to check.
// The required user mode extensions in X64 are (from AMD64 ABI Table A.1):
// fpu, tsc, cx8, cmov, mmx, sse, sse2, fxsr, syscall
static const uint64_t kDefaultCpuFeatures = (1 << SSE2 | 1 << CMOV);
#ifdef DEBUG
static bool initialized_;
#endif
static uint64_t supported_;
static uint64_t found_by_runtime_probing_;
DISALLOW_COPY_AND_ASSIGN(CpuFeatures);
};
class Assembler : public AssemblerBase {
private:
// We check before assembling an instruction that there is sufficient
// space to write an instruction and its relocation information.
// The relocation writer's position must be kGap bytes above the end of
// the generated instructions. This leaves enough space for the
// longest possible x64 instruction, 15 bytes, and the longest possible
// relocation information encoding, RelocInfoWriter::kMaxLength == 16.
// (There is a 15 byte limit on x64 instruction length that rules out some
// otherwise valid instructions.)
// This allows for a single, fast space check per instruction.
static const int kGap = 32;
public:
// Create an assembler. Instructions and relocation information are emitted
// into a buffer, with the instructions starting from the beginning and the
// relocation information starting from the end of the buffer. See CodeDesc
// for a detailed comment on the layout (globals.h).
//
// If the provided buffer is NULL, the assembler allocates and grows its own
// buffer, and buffer_size determines the initial buffer size. The buffer is
// owned by the assembler and deallocated upon destruction of the assembler.
//
// If the provided buffer is not NULL, the assembler uses the provided buffer
// for code generation and assumes its size to be buffer_size. If the buffer
// is too small, a fatal error occurs. No deallocation of the buffer is done
// upon destruction of the assembler.
Assembler(Isolate* isolate, void* buffer, int buffer_size);
~Assembler();
// Overrides the default provided by FLAG_debug_code.
void set_emit_debug_code(bool value) { emit_debug_code_ = value; }
// GetCode emits any pending (non-emitted) code and fills the descriptor
// desc. GetCode() is idempotent; it returns the same result if no other
// Assembler functions are invoked in between GetCode() calls.
void GetCode(CodeDesc* desc);
// Read/Modify the code target in the relative branch/call instruction at pc.
// On the x64 architecture, we use relative jumps with a 32-bit displacement
// to jump to other Code objects in the Code space in the heap.
// Jumps to C functions are done indirectly through a 64-bit register holding
// the absolute address of the target.
// These functions convert between absolute Addresses of Code objects and
// the relative displacements stored in the code.
static inline Address target_address_at(Address pc);
static inline void set_target_address_at(Address pc, Address target);
// This sets the branch destination (which is in the instruction on x64).
// This is for calls and branches within generated code.
inline static void set_target_at(Address instruction_payload,
Address target) {
set_target_address_at(instruction_payload, target);
}
// This sets the branch destination (which is a load instruction on x64).
// This is for calls and branches to runtime code.
inline static void set_external_target_at(Address instruction_payload,
Address target) {
*reinterpret_cast<Address*>(instruction_payload) = target;
}
inline Handle<Object> code_target_object_handle_at(Address pc);
// Number of bytes taken up by the branch target in the code.
static const int kCallTargetSize = 4; // Use 32-bit displacement.
static const int kExternalTargetSize = 8; // Use 64-bit absolute.
// Distance between the address of the code target in the call instruction
// and the return address pushed on the stack.
static const int kCallTargetAddressOffset = 4; // Use 32-bit displacement.
// Distance between the start of the JS return sequence and where the
// 32-bit displacement of a near call would be, relative to the pushed
// return address. TODO: Use return sequence length instead.
// Should equal Debug::kX64JSReturnSequenceLength - kCallTargetAddressOffset;
static const int kPatchReturnSequenceAddressOffset = 13 - 4;
// Distance between start of patched debug break slot and where the
// 32-bit displacement of a near call would be, relative to the pushed
// return address. TODO: Use return sequence length instead.
// Should equal Debug::kX64JSReturnSequenceLength - kCallTargetAddressOffset;
static const int kPatchDebugBreakSlotAddressOffset = 13 - 4;
// TODO(X64): Rename this, removing the "Real", after changing the above.
static const int kRealPatchReturnSequenceAddressOffset = 2;
// Some x64 JS code is padded with int3 to make it large
// enough to hold an instruction when the debugger patches it.
static const int kJumpInstructionLength = 13;
static const int kCallInstructionLength = 13;
static const int kJSReturnSequenceLength = 13;
static const int kShortCallInstructionLength = 5;
// The debug break slot must be able to contain a call instruction.
static const int kDebugBreakSlotLength = kCallInstructionLength;
// One byte opcode for test eax,0xXXXXXXXX.
static const byte kTestEaxByte = 0xA9;
// One byte opcode for test al, 0xXX.
static const byte kTestAlByte = 0xA8;
// One byte opcode for nop.
static const byte kNopByte = 0x90;
// One byte prefix for a short conditional jump.
static const byte kJccShortPrefix = 0x70;
static const byte kJncShortOpcode = kJccShortPrefix | not_carry;
static const byte kJcShortOpcode = kJccShortPrefix | carry;
// ---------------------------------------------------------------------------
// Code generation
//
// Function names correspond one-to-one to x64 instruction mnemonics.
// Unless specified otherwise, instructions operate on 64-bit operands.
//
// If we need versions of an assembly instruction that operate on different
// width arguments, we add a single-letter suffix specifying the width.
// This is done for the following instructions: mov, cmp, inc, dec,
// add, sub, and test.
// There are no versions of these instructions without the suffix.
// - Instructions on 8-bit (byte) operands/registers have a trailing 'b'.
// - Instructions on 16-bit (word) operands/registers have a trailing 'w'.
// - Instructions on 32-bit (doubleword) operands/registers use 'l'.
// - Instructions on 64-bit (quadword) operands/registers use 'q'.
//
// Some mnemonics, such as "and", are the same as C++ keywords.
// Naming conflicts with C++ keywords are resolved by adding a trailing '_'.
// Insert the smallest number of nop instructions
// possible to align the pc offset to a multiple
// of m, where m must be a power of 2.
void Align(int m);
// Aligns code to something that's optimal for a jump target for the platform.
void CodeTargetAlign();
// Stack
void pushfq();
void popfq();
void push(Immediate value);
// Push a 32 bit integer, and guarantee that it is actually pushed as a
// 32 bit value, the normal push will optimize the 8 bit case.
void push_imm32(int32_t imm32);
void push(Register src);
void push(const Operand& src);
void pop(Register dst);
void pop(const Operand& dst);
void enter(Immediate size);
void leave();
// Moves
void movb(Register dst, const Operand& src);
void movb(Register dst, Immediate imm);
void movb(const Operand& dst, Register src);
// Move the low 16 bits of a 64-bit register value to a 16-bit
// memory location.
void movw(const Operand& dst, Register src);
void movl(Register dst, Register src);
void movl(Register dst, const Operand& src);
void movl(const Operand& dst, Register src);
void movl(const Operand& dst, Immediate imm);
// Load a 32-bit immediate value, zero-extended to 64 bits.
void movl(Register dst, Immediate imm32);
// Move 64 bit register value to 64-bit memory location.
void movq(const Operand& dst, Register src);
// Move 64 bit memory location to 64-bit register value.
void movq(Register dst, const Operand& src);
void movq(Register dst, Register src);
// Sign extends immediate 32-bit value to 64 bits.
void movq(Register dst, Immediate x);
// Move the offset of the label location relative to the current
// position (after the move) to the destination.
void movl(const Operand& dst, Label* src);
// Move sign extended immediate to memory location.
void movq(const Operand& dst, Immediate value);
// Instructions to load a 64-bit immediate into a register.
// All 64-bit immediates must have a relocation mode.
void movq(Register dst, void* ptr, RelocInfo::Mode rmode);
void movq(Register dst, int64_t value, RelocInfo::Mode rmode);
void movq(Register dst, const char* s, RelocInfo::Mode rmode);
// Moves the address of the external reference into the register.
void movq(Register dst, ExternalReference ext);
void movq(Register dst, Handle<Object> handle, RelocInfo::Mode rmode);
void movsxbq(Register dst, const Operand& src);
void movsxwq(Register dst, const Operand& src);
void movsxlq(Register dst, Register src);
void movsxlq(Register dst, const Operand& src);
void movzxbq(Register dst, const Operand& src);
void movzxbl(Register dst, const Operand& src);
void movzxwq(Register dst, const Operand& src);
void movzxwl(Register dst, const Operand& src);
// Repeated moves.
void repmovsb();
void repmovsw();
void repmovsl();
void repmovsq();
// Instruction to load from an immediate 64-bit pointer into RAX.
void load_rax(void* ptr, RelocInfo::Mode rmode);
void load_rax(ExternalReference ext);
// Conditional moves.
void cmovq(Condition cc, Register dst, Register src);
void cmovq(Condition cc, Register dst, const Operand& src);
void cmovl(Condition cc, Register dst, Register src);
void cmovl(Condition cc, Register dst, const Operand& src);
// Exchange two registers
void xchg(Register dst, Register src);
// Arithmetics
void addl(Register dst, Register src) {
arithmetic_op_32(0x03, dst, src);
}
void addl(Register dst, Immediate src) {
immediate_arithmetic_op_32(0x0, dst, src);
}
void addl(Register dst, const Operand& src) {
arithmetic_op_32(0x03, dst, src);
}
void addl(const Operand& dst, Immediate src) {
immediate_arithmetic_op_32(0x0, dst, src);
}
void addq(Register dst, Register src) {
arithmetic_op(0x03, dst, src);
}
void addq(Register dst, const Operand& src) {
arithmetic_op(0x03, dst, src);
}
void addq(const Operand& dst, Register src) {
arithmetic_op(0x01, src, dst);
}
void addq(Register dst, Immediate src) {
immediate_arithmetic_op(0x0, dst, src);
}
void addq(const Operand& dst, Immediate src) {
immediate_arithmetic_op(0x0, dst, src);
}
void sbbl(Register dst, Register src) {
arithmetic_op_32(0x1b, dst, src);
}
void sbbq(Register dst, Register src) {
arithmetic_op(0x1b, dst, src);
}
void cmpb(Register dst, Immediate src) {
immediate_arithmetic_op_8(0x7, dst, src);
}
void cmpb_al(Immediate src);
void cmpb(Register dst, Register src) {
arithmetic_op(0x3A, dst, src);
}
void cmpb(Register dst, const Operand& src) {
arithmetic_op(0x3A, dst, src);
}
void cmpb(const Operand& dst, Register src) {
arithmetic_op(0x38, src, dst);
}
void cmpb(const Operand& dst, Immediate src) {
immediate_arithmetic_op_8(0x7, dst, src);
}
void cmpw(const Operand& dst, Immediate src) {
immediate_arithmetic_op_16(0x7, dst, src);
}
void cmpw(Register dst, Immediate src) {
immediate_arithmetic_op_16(0x7, dst, src);
}
void cmpw(Register dst, const Operand& src) {
arithmetic_op_16(0x3B, dst, src);
}
void cmpw(Register dst, Register src) {
arithmetic_op_16(0x3B, dst, src);
}
void cmpw(const Operand& dst, Register src) {
arithmetic_op_16(0x39, src, dst);
}
void cmpl(Register dst, Register src) {
arithmetic_op_32(0x3B, dst, src);
}
void cmpl(Register dst, const Operand& src) {
arithmetic_op_32(0x3B, dst, src);
}
void cmpl(const Operand& dst, Register src) {
arithmetic_op_32(0x39, src, dst);
}
void cmpl(Register dst, Immediate src) {
immediate_arithmetic_op_32(0x7, dst, src);
}
void cmpl(const Operand& dst, Immediate src) {
immediate_arithmetic_op_32(0x7, dst, src);
}
void cmpq(Register dst, Register src) {
arithmetic_op(0x3B, dst, src);
}
void cmpq(Register dst, const Operand& src) {
arithmetic_op(0x3B, dst, src);
}
void cmpq(const Operand& dst, Register src) {
arithmetic_op(0x39, src, dst);
}
void cmpq(Register dst, Immediate src) {
immediate_arithmetic_op(0x7, dst, src);
}
void cmpq(const Operand& dst, Immediate src) {
immediate_arithmetic_op(0x7, dst, src);
}
void and_(Register dst, Register src) {
arithmetic_op(0x23, dst, src);
}
void and_(Register dst, const Operand& src) {
arithmetic_op(0x23, dst, src);
}
void and_(const Operand& dst, Register src) {
arithmetic_op(0x21, src, dst);
}
void and_(Register dst, Immediate src) {
immediate_arithmetic_op(0x4, dst, src);
}
void and_(const Operand& dst, Immediate src) {
immediate_arithmetic_op(0x4, dst, src);
}
void andl(Register dst, Immediate src) {
immediate_arithmetic_op_32(0x4, dst, src);
}
void andl(Register dst, Register src) {
arithmetic_op_32(0x23, dst, src);
}
void andl(Register dst, const Operand& src) {
arithmetic_op_32(0x23, dst, src);
}
void andb(Register dst, Immediate src) {
immediate_arithmetic_op_8(0x4, dst, src);
}
void decq(Register dst);
void decq(const Operand& dst);
void decl(Register dst);
void decl(const Operand& dst);
void decb(Register dst);
void decb(const Operand& dst);
// Sign-extends rax into rdx:rax.
void cqo();
// Sign-extends eax into edx:eax.
void cdq();
// Divide rdx:rax by src. Quotient in rax, remainder in rdx.
void idivq(Register src);
// Divide edx:eax by lower 32 bits of src. Quotient in eax, rem. in edx.
void idivl(Register src);
// Signed multiply instructions.
void imul(Register src); // rdx:rax = rax * src.
void imul(Register dst, Register src); // dst = dst * src.
void imul(Register dst, const Operand& src); // dst = dst * src.
void imul(Register dst, Register src, Immediate imm); // dst = src * imm.
// Signed 32-bit multiply instructions.
void imull(Register dst, Register src); // dst = dst * src.
void imull(Register dst, const Operand& src); // dst = dst * src.
void imull(Register dst, Register src, Immediate imm); // dst = src * imm.
void incq(Register dst);
void incq(const Operand& dst);
void incl(Register dst);
void incl(const Operand& dst);
void lea(Register dst, const Operand& src);
void leal(Register dst, const Operand& src);
// Multiply rax by src, put the result in rdx:rax.
void mul(Register src);
void neg(Register dst);
void neg(const Operand& dst);
void negl(Register dst);
void not_(Register dst);
void not_(const Operand& dst);
void notl(Register dst);
void or_(Register dst, Register src) {
arithmetic_op(0x0B, dst, src);
}
void orl(Register dst, Register src) {
arithmetic_op_32(0x0B, dst, src);
}
void or_(Register dst, const Operand& src) {
arithmetic_op(0x0B, dst, src);
}
void orl(Register dst, const Operand& src) {
arithmetic_op_32(0x0B, dst, src);
}
void or_(const Operand& dst, Register src) {
arithmetic_op(0x09, src, dst);
}
void or_(Register dst, Immediate src) {
immediate_arithmetic_op(0x1, dst, src);
}
void orl(Register dst, Immediate src) {
immediate_arithmetic_op_32(0x1, dst, src);
}
void or_(const Operand& dst, Immediate src) {
immediate_arithmetic_op(0x1, dst, src);
}
void orl(const Operand& dst, Immediate src) {
immediate_arithmetic_op_32(0x1, dst, src);
}
void rcl(Register dst, Immediate imm8) {
shift(dst, imm8, 0x2);
}
void rol(Register dst, Immediate imm8) {
shift(dst, imm8, 0x0);
}
void rcr(Register dst, Immediate imm8) {
shift(dst, imm8, 0x3);
}
void ror(Register dst, Immediate imm8) {
shift(dst, imm8, 0x1);
}
// Shifts dst:src left by cl bits, affecting only dst.
void shld(Register dst, Register src);
// Shifts src:dst right by cl bits, affecting only dst.
void shrd(Register dst, Register src);
// Shifts dst right, duplicating sign bit, by shift_amount bits.
// Shifting by 1 is handled efficiently.
void sar(Register dst, Immediate shift_amount) {
shift(dst, shift_amount, 0x7);
}
// Shifts dst right, duplicating sign bit, by shift_amount bits.
// Shifting by 1 is handled efficiently.
void sarl(Register dst, Immediate shift_amount) {
shift_32(dst, shift_amount, 0x7);
}
// Shifts dst right, duplicating sign bit, by cl % 64 bits.
void sar_cl(Register dst) {
shift(dst, 0x7);
}
// Shifts dst right, duplicating sign bit, by cl % 64 bits.
void sarl_cl(Register dst) {
shift_32(dst, 0x7);
}
void shl(Register dst, Immediate shift_amount) {
shift(dst, shift_amount, 0x4);
}
void shl_cl(Register dst) {
shift(dst, 0x4);
}
void shll_cl(Register dst) {
shift_32(dst, 0x4);
}
void shll(Register dst, Immediate shift_amount) {
shift_32(dst, shift_amount, 0x4);
}
void shr(Register dst, Immediate shift_amount) {
shift(dst, shift_amount, 0x5);
}
void shr_cl(Register dst) {
shift(dst, 0x5);
}
void shrl_cl(Register dst) {
shift_32(dst, 0x5);
}
void shrl(Register dst, Immediate shift_amount) {
shift_32(dst, shift_amount, 0x5);
}
void store_rax(void* dst, RelocInfo::Mode mode);
void store_rax(ExternalReference ref);
void subq(Register dst, Register src) {
arithmetic_op(0x2B, dst, src);
}
void subq(Register dst, const Operand& src) {
arithmetic_op(0x2B, dst, src);
}
void subq(const Operand& dst, Register src) {
arithmetic_op(0x29, src, dst);
}
void subq(Register dst, Immediate src) {
immediate_arithmetic_op(0x5, dst, src);
}
void subq(const Operand& dst, Immediate src) {
immediate_arithmetic_op(0x5, dst, src);
}
void subl(Register dst, Register src) {
arithmetic_op_32(0x2B, dst, src);
}
void subl(Register dst, const Operand& src) {
arithmetic_op_32(0x2B, dst, src);
}
void subl(const Operand& dst, Immediate src) {
immediate_arithmetic_op_32(0x5, dst, src);
}
void subl(Register dst, Immediate src) {
immediate_arithmetic_op_32(0x5, dst, src);
}
void subb(Register dst, Immediate src) {
immediate_arithmetic_op_8(0x5, dst, src);
}
void testb(Register dst, Register src);
void testb(Register reg, Immediate mask);
void testb(const Operand& op, Immediate mask);
void testb(const Operand& op, Register reg);
void testl(Register dst, Register src);
void testl(Register reg, Immediate mask);
void testl(const Operand& op, Immediate mask);
void testq(const Operand& op, Register reg);
void testq(Register dst, Register src);
void testq(Register dst, Immediate mask);
void xor_(Register dst, Register src) {
if (dst.code() == src.code()) {
arithmetic_op_32(0x33, dst, src);
} else {
arithmetic_op(0x33, dst, src);
}
}
void xorl(Register dst, Register src) {
arithmetic_op_32(0x33, dst, src);
}
void xorl(Register dst, const Operand& src) {
arithmetic_op_32(0x33, dst, src);
}
void xorl(Register dst, Immediate src) {
immediate_arithmetic_op_32(0x6, dst, src);
}
void xorl(const Operand& dst, Immediate src) {
immediate_arithmetic_op_32(0x6, dst, src);
}
void xor_(Register dst, const Operand& src) {
arithmetic_op(0x33, dst, src);
}
void xor_(const Operand& dst, Register src) {
arithmetic_op(0x31, src, dst);
}
void xor_(Register dst, Immediate src) {
immediate_arithmetic_op(0x6, dst, src);
}
void xor_(const Operand& dst, Immediate src) {
immediate_arithmetic_op(0x6, dst, src);
}
// Bit operations.
void bt(const Operand& dst, Register src);
void bts(const Operand& dst, Register src);
// Miscellaneous
void clc();
void cld();
void cpuid();
void hlt();
void int3();
void nop();
void nop(int n);
void rdtsc();
void ret(int imm16);
void setcc(Condition cc, Register reg);
// Label operations & relative jumps (PPUM Appendix D)
//
// Takes a branch opcode (cc) and a label (L) and generates
// either a backward branch or a forward branch and links it
// to the label fixup chain. Usage:
//
// Label L; // unbound label
// j(cc, &L); // forward branch to unbound label
// bind(&L); // bind label to the current pc
// j(cc, &L); // backward branch to bound label
// bind(&L); // illegal: a label may be bound only once
//
// Note: The same Label can be used for forward and backward branches
// but it may be bound only once.
void bind(Label* L); // binds an unbound label L to the current code position
void bind(NearLabel* L);
// Calls
// Call near relative 32-bit displacement, relative to next instruction.
void call(Label* L);
void call(Handle<Code> target, RelocInfo::Mode rmode);
// Calls directly to the given address using a relative offset.
// Should only ever be used in Code objects for calls within the
// same Code object. Should not be used when generating new code (use labels),
// but only when patching existing code.
void call(Address target);
// Call near absolute indirect, address in register
void call(Register adr);
// Call near indirect
void call(const Operand& operand);
// Jumps
// Jump short or near relative.
// Use a 32-bit signed displacement.
void jmp(Label* L); // unconditional jump to L
void jmp(Handle<Code> target, RelocInfo::Mode rmode);
// Jump near absolute indirect (r64)
void jmp(Register adr);
// Jump near absolute indirect (m64)
void jmp(const Operand& src);
// Short jump
void jmp(NearLabel* L);
// Conditional jumps
void j(Condition cc, Label* L);
void j(Condition cc, Handle<Code> target, RelocInfo::Mode rmode);
// Conditional short jump
void j(Condition cc, NearLabel* L, Hint hint = no_hint);
// Floating-point operations
void fld(int i);
void fld1();
void fldz();
void fldpi();
void fldln2();
void fld_s(const Operand& adr);
void fld_d(const Operand& adr);
void fstp_s(const Operand& adr);
void fstp_d(const Operand& adr);
void fstp(int index);
void fild_s(const Operand& adr);
void fild_d(const Operand& adr);
void fist_s(const Operand& adr);
void fistp_s(const Operand& adr);
void fistp_d(const Operand& adr);
void fisttp_s(const Operand& adr);
void fisttp_d(const Operand& adr);
void fabs();
void fchs();
void fadd(int i);
void fsub(int i);
void fmul(int i);
void fdiv(int i);
void fisub_s(const Operand& adr);
void faddp(int i = 1);
void fsubp(int i = 1);
void fsubrp(int i = 1);
void fmulp(int i = 1);
void fdivp(int i = 1);
void fprem();
void fprem1();
void fxch(int i = 1);
void fincstp();
void ffree(int i = 0);
void ftst();
void fucomp(int i);
void fucompp();
void fucomi(int i);
void fucomip();
void fcompp();
void fnstsw_ax();
void fwait();
void fnclex();
void fsin();
void fcos();
void fyl2x();
void frndint();
void sahf();
// SSE2 instructions
void movd(XMMRegister dst, Register src);
void movd(Register dst, XMMRegister src);
void movq(XMMRegister dst, Register src);
void movq(Register dst, XMMRegister src);
void extractps(Register dst, XMMRegister src, byte imm8);
void movsd(const Operand& dst, XMMRegister src);
void movsd(XMMRegister dst, XMMRegister src);
void movsd(XMMRegister dst, const Operand& src);
void movdqa(const Operand& dst, XMMRegister src);
void movdqa(XMMRegister dst, const Operand& src);
void movss(XMMRegister dst, const Operand& src);
void movss(const Operand& dst, XMMRegister src);
void cvttss2si(Register dst, const Operand& src);
void cvttss2si(Register dst, XMMRegister src);
void cvttsd2si(Register dst, const Operand& src);
void cvttsd2si(Register dst, XMMRegister src);
void cvttsd2siq(Register dst, XMMRegister src);
void cvtlsi2sd(XMMRegister dst, const Operand& src);
void cvtlsi2sd(XMMRegister dst, Register src);
void cvtqsi2sd(XMMRegister dst, const Operand& src);
void cvtqsi2sd(XMMRegister dst, Register src);
void cvtlsi2ss(XMMRegister dst, Register src);
void cvtss2sd(XMMRegister dst, XMMRegister src);
void cvtss2sd(XMMRegister dst, const Operand& src);
void cvtsd2ss(XMMRegister dst, XMMRegister src);
void cvtsd2si(Register dst, XMMRegister src);
void cvtsd2siq(Register dst, XMMRegister src);
void addsd(XMMRegister dst, XMMRegister src);
void subsd(XMMRegister dst, XMMRegister src);
void mulsd(XMMRegister dst, XMMRegister src);
void divsd(XMMRegister dst, XMMRegister src);
void andpd(XMMRegister dst, XMMRegister src);
void orpd(XMMRegister dst, XMMRegister src);
void xorpd(XMMRegister dst, XMMRegister src);
void sqrtsd(XMMRegister dst, XMMRegister src);
void ucomisd(XMMRegister dst, XMMRegister src);
void ucomisd(XMMRegister dst, const Operand& src);
void movmskpd(Register dst, XMMRegister src);
// The first argument is the reg field, the second argument is the r/m field.
void emit_sse_operand(XMMRegister dst, XMMRegister src);
void emit_sse_operand(XMMRegister reg, const Operand& adr);
void emit_sse_operand(XMMRegister dst, Register src);
void emit_sse_operand(Register dst, XMMRegister src);
// Debugging
void Print();
// Check the code size generated from label to here.
int SizeOfCodeGeneratedSince(Label* l) { return pc_offset() - l->pos(); }
// Mark address of the ExitJSFrame code.
void RecordJSReturn();
// Mark address of a debug break slot.
void RecordDebugBreakSlot();
// Record a comment relocation entry that can be used by a disassembler.
// Use --code-comments to enable.
void RecordComment(const char* msg, bool force = false);
// Writes a single word of data in the code stream.
// Used for inline tables, e.g., jump-tables.
void db(uint8_t data);
void dd(uint32_t data);
int pc_offset() const { return static_cast<int>(pc_ - buffer_); }
PositionsRecorder* positions_recorder() { return &positions_recorder_; }
// Check if there is less than kGap bytes available in the buffer.
// If this is the case, we need to grow the buffer before emitting
// an instruction or relocation information.
inline bool buffer_overflow() const {
return pc_ >= reloc_info_writer.pos() - kGap;
}
// Get the number of bytes available in the buffer.
inline int available_space() const {
return static_cast<int>(reloc_info_writer.pos() - pc_);
}
static bool IsNop(Address addr) { return *addr == 0x90; }
// Avoid overflows for displacements etc.
static const int kMaximalBufferSize = 512*MB;
static const int kMinimalBufferSize = 4*KB;
protected:
bool emit_debug_code() const { return emit_debug_code_; }
private:
byte* addr_at(int pos) { return buffer_ + pos; }
byte byte_at(int pos) { return buffer_[pos]; }
void set_byte_at(int pos, byte value) { buffer_[pos] = value; }
uint32_t long_at(int pos) {
return *reinterpret_cast<uint32_t*>(addr_at(pos));
}
void long_at_put(int pos, uint32_t x) {
*reinterpret_cast<uint32_t*>(addr_at(pos)) = x;
}
// code emission
void GrowBuffer();
void emit(byte x) { *pc_++ = x; }
inline void emitl(uint32_t x);
inline void emitq(uint64_t x, RelocInfo::Mode rmode);
inline void emitw(uint16_t x);
inline void emit_code_target(Handle<Code> target, RelocInfo::Mode rmode);
void emit(Immediate x) { emitl(x.value_); }
// Emits a REX prefix that encodes a 64-bit operand size and
// the top bit of both register codes.
// High bit of reg goes to REX.R, high bit of rm_reg goes to REX.B.
// REX.W is set.
inline void emit_rex_64(XMMRegister reg, Register rm_reg);
inline void emit_rex_64(Register reg, XMMRegister rm_reg);
inline void emit_rex_64(Register reg, Register rm_reg);
// Emits a REX prefix that encodes a 64-bit operand size and
// the top bit of the destination, index, and base register codes.
// The high bit of reg is used for REX.R, the high bit of op's base
// register is used for REX.B, and the high bit of op's index register
// is used for REX.X. REX.W is set.
inline void emit_rex_64(Register reg, const Operand& op);
inline void emit_rex_64(XMMRegister reg, const Operand& op);
// Emits a REX prefix that encodes a 64-bit operand size and
// the top bit of the register code.
// The high bit of register is used for REX.B.
// REX.W is set and REX.R and REX.X are clear.
inline void emit_rex_64(Register rm_reg);
// Emits a REX prefix that encodes a 64-bit operand size and
// the top bit of the index and base register codes.
// The high bit of op's base register is used for REX.B, and the high
// bit of op's index register is used for REX.X.
// REX.W is set and REX.R clear.
inline void emit_rex_64(const Operand& op);
// Emit a REX prefix that only sets REX.W to choose a 64-bit operand size.
void emit_rex_64() { emit(0x48); }
// High bit of reg goes to REX.R, high bit of rm_reg goes to REX.B.
// REX.W is clear.
inline void emit_rex_32(Register reg, Register rm_reg);
// The high bit of reg is used for REX.R, the high bit of op's base
// register is used for REX.B, and the high bit of op's index register
// is used for REX.X. REX.W is cleared.
inline void emit_rex_32(Register reg, const Operand& op);
// High bit of rm_reg goes to REX.B.
// REX.W, REX.R and REX.X are clear.
inline void emit_rex_32(Register rm_reg);
// High bit of base goes to REX.B and high bit of index to REX.X.
// REX.W and REX.R are clear.
inline void emit_rex_32(const Operand& op);
// High bit of reg goes to REX.R, high bit of rm_reg goes to REX.B.
// REX.W is cleared. If no REX bits are set, no byte is emitted.
inline void emit_optional_rex_32(Register reg, Register rm_reg);
// The high bit of reg is used for REX.R, the high bit of op's base
// register is used for REX.B, and the high bit of op's index register
// is used for REX.X. REX.W is cleared. If no REX bits are set, nothing
// is emitted.
inline void emit_optional_rex_32(Register reg, const Operand& op);
// As for emit_optional_rex_32(Register, Register), except that
// the registers are XMM registers.
inline void emit_optional_rex_32(XMMRegister reg, XMMRegister base);
// As for emit_optional_rex_32(Register, Register), except that
// one of the registers is an XMM registers.
inline void emit_optional_rex_32(XMMRegister reg, Register base);
// As for emit_optional_rex_32(Register, Register), except that
// one of the registers is an XMM registers.
inline void emit_optional_rex_32(Register reg, XMMRegister base);
// As for emit_optional_rex_32(Register, const Operand&), except that
// the register is an XMM register.
inline void emit_optional_rex_32(XMMRegister reg, const Operand& op);
// Optionally do as emit_rex_32(Register) if the register number has
// the high bit set.
inline void emit_optional_rex_32(Register rm_reg);
// Optionally do as emit_rex_32(const Operand&) if the operand register
// numbers have a high bit set.
inline void emit_optional_rex_32(const Operand& op);
// Emit the ModR/M byte, and optionally the SIB byte and
// 1- or 4-byte offset for a memory operand. Also encodes
// the second operand of the operation, a register or operation
// subcode, into the reg field of the ModR/M byte.
void emit_operand(Register reg, const Operand& adr) {
emit_operand(reg.low_bits(), adr);
}
// Emit the ModR/M byte, and optionally the SIB byte and
// 1- or 4-byte offset for a memory operand. Also used to encode
// a three-bit opcode extension into the ModR/M byte.
void emit_operand(int rm, const Operand& adr);
// Emit a ModR/M byte with registers coded in the reg and rm_reg fields.
void emit_modrm(Register reg, Register rm_reg) {
emit(0xC0 | reg.low_bits() << 3 | rm_reg.low_bits());
}
// Emit a ModR/M byte with an operation subcode in the reg field and
// a register in the rm_reg field.
void emit_modrm(int code, Register rm_reg) {
ASSERT(is_uint3(code));
emit(0xC0 | code << 3 | rm_reg.low_bits());
}
// Emit the code-object-relative offset of the label's position
inline void emit_code_relative_offset(Label* label);
// Emit machine code for one of the operations ADD, ADC, SUB, SBC,
// AND, OR, XOR, or CMP. The encodings of these operations are all
// similar, differing just in the opcode or in the reg field of the
// ModR/M byte.
void arithmetic_op_16(byte opcode, Register reg, Register rm_reg);
void arithmetic_op_16(byte opcode, Register reg, const Operand& rm_reg);
void arithmetic_op_32(byte opcode, Register reg, Register rm_reg);
void arithmetic_op_32(byte opcode, Register reg, const Operand& rm_reg);
void arithmetic_op(byte opcode, Register reg, Register rm_reg);
void arithmetic_op(byte opcode, Register reg, const Operand& rm_reg);
void immediate_arithmetic_op(byte subcode, Register dst, Immediate src);
void immediate_arithmetic_op(byte subcode, const Operand& dst, Immediate src);
// Operate on a byte in memory or register.
void immediate_arithmetic_op_8(byte subcode,
Register dst,
Immediate src);
void immediate_arithmetic_op_8(byte subcode,
const Operand& dst,
Immediate src);
// Operate on a word in memory or register.
void immediate_arithmetic_op_16(byte subcode,
Register dst,
Immediate src);
void immediate_arithmetic_op_16(byte subcode,
const Operand& dst,
Immediate src);
// Operate on a 32-bit word in memory or register.
void immediate_arithmetic_op_32(byte subcode,
Register dst,
Immediate src);
void immediate_arithmetic_op_32(byte subcode,
const Operand& dst,
Immediate src);
// Emit machine code for a shift operation.
void shift(Register dst, Immediate shift_amount, int subcode);
void shift_32(Register dst, Immediate shift_amount, int subcode);
// Shift dst by cl % 64 bits.
void shift(Register dst, int subcode);
void shift_32(Register dst, int subcode);
void emit_farith(int b1, int b2, int i);
// labels
// void print(Label* L);
void bind_to(Label* L, int pos);
// record reloc info for current pc_
void RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data = 0);
friend class CodePatcher;
friend class EnsureSpace;
friend class RegExpMacroAssemblerX64;
// Code buffer:
// The buffer into which code and relocation info are generated.
byte* buffer_;
int buffer_size_;
// True if the assembler owns the buffer, false if buffer is external.
bool own_buffer_;
// code generation
byte* pc_; // the program counter; moves forward
RelocInfoWriter reloc_info_writer;
List< Handle<Code> > code_targets_;
PositionsRecorder positions_recorder_;
bool emit_debug_code_;
friend class PositionsRecorder;
};
// Helper class that ensures that there is enough space for generating
// instructions and relocation information. The constructor makes
// sure that there is enough space and (in debug mode) the destructor
// checks that we did not generate too much.
class EnsureSpace BASE_EMBEDDED {
public:
explicit EnsureSpace(Assembler* assembler) : assembler_(assembler) {
if (assembler_->buffer_overflow()) assembler_->GrowBuffer();
#ifdef DEBUG
space_before_ = assembler_->available_space();
#endif
}
#ifdef DEBUG
~EnsureSpace() {
int bytes_generated = space_before_ - assembler_->available_space();
ASSERT(bytes_generated < assembler_->kGap);
}
#endif
private:
Assembler* assembler_;
#ifdef DEBUG
int space_before_;
#endif
};
} } // namespace v8::internal
#endif // V8_X64_ASSEMBLER_X64_H_