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// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
// Declares a Simulator for ARM64 instructions if we are not generating a native
// ARM64 binary. This Simulator allows us to run and debug ARM64 code generation
// on regular desktop machines.
// Dart calls into generated code by "calling" the InvokeDartCode stub,
// which will start execution in the Simulator or forwards to the real entry
// on a ARM64 HW platform.
#error Do not include simulator_arm64.h directly; use simulator.h.
#include "vm/constants_arm64.h"
namespace dart {
class Isolate;
class Mutex;
class RawObject;
class SimulatorSetjmpBuffer;
class Thread;
typedef struct {
union {
int64_t i64[2];
int32_t i32[4];
} bits;
} simd_value_t;
class Simulator {
static const uword kSimulatorStackUnderflowSize = 64;
// The currently executing Simulator instance, which is associated to the
// current isolate
static Simulator* Current();
// Accessors for register state.
// The default value for R31Type has to be R31IsSP because get_register is
// accessed from architecture independent code through SPREG without
// specifying the type. We also can't translate a dummy value for SPREG into
// a real value because the architecture independent code expects SPREG to
// be a real register value.
void set_register(Instr* instr,
Register reg,
int64_t value,
R31Type r31t = R31IsSP);
int64_t get_register(Register reg, R31Type r31t = R31IsSP) const;
void set_wregister(Register reg, int32_t value, R31Type r31t = R31IsSP);
int32_t get_wregister(Register reg, R31Type r31t = R31IsSP) const;
int32_t get_vregisters(VRegister reg, int idx) const;
void set_vregisters(VRegister reg, int idx, int32_t value);
int64_t get_vregisterd(VRegister reg, int idx) const;
void set_vregisterd(VRegister reg, int idx, int64_t value);
void get_vregister(VRegister reg, simd_value_t* value) const;
void set_vregister(VRegister reg, const simd_value_t& value);
int64_t get_sp() const { return get_register(SPREG); }
int64_t get_pc() const;
int64_t get_last_pc() const;
void set_pc(int64_t pc);
// High address.
uword stack_base() const { return stack_base_; }
// Low address.
uword stack_limit() const { return stack_limit_; }
// Accessor to the instruction counter.
uint64_t get_icount() const { return icount_; }
// The thread's top_exit_frame_info refers to a Dart frame in the simulator
// stack. The simulator's top_exit_frame_info refers to a C++ frame in the
// native stack.
uword top_exit_frame_info() const { return top_exit_frame_info_; }
void set_top_exit_frame_info(uword value) { top_exit_frame_info_ = value; }
// Call on program start.
static void InitOnce();
// Dart generally calls into generated code with 4 parameters. This is a
// convenience function, which sets up the simulator state and grabs the
// result on return. The return value is R0. The parameters are placed in
// R0-3.
int64_t Call(int64_t entry,
int64_t parameter0,
int64_t parameter1,
int64_t parameter2,
int64_t parameter3,
bool fp_return = false,
bool fp_args = false);
// Runtime and native call support.
enum CallKind {
static uword RedirectExternalReference(uword function,
CallKind call_kind,
int argument_count);
static uword FunctionForRedirect(uword redirect);
void JumpToFrame(uword pc, uword sp, uword fp, Thread* thread);
// Known bad pc value to ensure that the simulator does not execute
// without being properly setup.
static const uword kBadLR = -1;
// A pc value used to signal the simulator to stop execution. Generally
// the lr is set to this value on transition from native C code to
// simulated execution, so that the simulator can "return" to the native
// C code.
static const uword kEndSimulatingPC = -2;
// CPU state.
int64_t registers_[kNumberOfCpuRegisters];
bool n_flag_;
bool z_flag_;
bool c_flag_;
bool v_flag_;
simd_value_t vregisters_[kNumberOfVRegisters];
// Simulator support.
int64_t last_pc_;
int64_t pc_;
char* stack_;
uword stack_limit_;
uword stack_base_;
bool pc_modified_;
uint64_t icount_;
static int64_t flag_stop_sim_at_;
SimulatorSetjmpBuffer* last_setjmp_buffer_;
uword top_exit_frame_info_;
// Registered breakpoints.
Instr* break_pc_;
int64_t break_instr_;
// Illegal memory access support.
static bool IsIllegalAddress(uword addr) { return addr < 64 * 1024; }
void HandleIllegalAccess(uword addr, Instr* instr);
// Handles an unaligned memory access.
void UnalignedAccess(const char* msg, uword addr, Instr* instr);
// Handles a legal instruction that the simulator does not implement.
void UnimplementedInstruction(Instr* instr);
// Unsupported instructions use Format to print an error and stop execution.
void Format(Instr* instr, const char* format);
inline uint8_t ReadBU(uword addr);
inline int8_t ReadB(uword addr);
inline void WriteB(uword addr, uint8_t value);
inline uint16_t ReadHU(uword addr, Instr* instr);
inline int16_t ReadH(uword addr, Instr* instr);
inline void WriteH(uword addr, uint16_t value, Instr* instr);
inline uint32_t ReadWU(uword addr, Instr* instr);
inline int32_t ReadW(uword addr, Instr* instr);
inline void WriteW(uword addr, uint32_t value, Instr* instr);
inline intptr_t ReadX(uword addr, Instr* instr);
inline void WriteX(uword addr, intptr_t value, Instr* instr);
// Synchronization primitives support.
void ClearExclusive();
intptr_t ReadExclusiveX(uword addr, Instr* instr);
intptr_t WriteExclusiveX(uword addr, intptr_t value, Instr* instr);
// 32 bit versions.
intptr_t ReadExclusiveW(uword addr, Instr* instr);
intptr_t WriteExclusiveW(uword addr, intptr_t value, Instr* instr);
// Exclusive access reservation: address and value observed during
// load-exclusive. Store-exclusive verifies that address is the same and
// performs atomic compare-and-swap with remembered value to observe value
// changes. This implementation of ldxr/stxr instructions does not detect
// ABA situation and our uses of ldxr/stxr don't need this detection.
uword exclusive_access_addr_;
uword exclusive_access_value_;
// Helper functions to set the conditional flags in the architecture state.
void SetNZFlagsW(int32_t val);
bool CarryFromW(int32_t left, int32_t right, int32_t carry);
bool OverflowFromW(int32_t left, int32_t right, int32_t carry);
void SetNZFlagsX(int64_t val);
bool CarryFromX(int64_t alu_out, int64_t left, int64_t right, bool addition);
bool OverflowFromX(int64_t alu_out,
int64_t left,
int64_t right,
bool addition);
void SetCFlag(bool val);
void SetVFlag(bool val);
int64_t ShiftOperand(uint8_t reg_size,
int64_t value,
Shift shift_type,
uint8_t amount);
int64_t ExtendOperand(uint8_t reg_size,
int64_t value,
Extend extend_type,
uint8_t amount);
int64_t DecodeShiftExtendOperand(Instr* instr);
bool ConditionallyExecute(Instr* instr);
void DoRedirectedCall(Instr* instr);
// Decode instructions.
void InstructionDecode(Instr* instr);
#define DECODE_OP(op) void Decode##op(Instr* instr);
#undef DECODE_OP
// Executes ARM64 instructions until the PC reaches kEndSimulatingPC.
void Execute();
// Returns true if tracing of executed instructions is enabled.
bool IsTracingExecution() const;
// Longjmp support for exceptions.
SimulatorSetjmpBuffer* last_setjmp_buffer() { return last_setjmp_buffer_; }
void set_last_setjmp_buffer(SimulatorSetjmpBuffer* buffer) {
last_setjmp_buffer_ = buffer;
friend class SimulatorDebugger;
friend class SimulatorSetjmpBuffer;
} // namespace dart