blob: 0d9f446d83bbf8e851f017f5a9c92c4fa97a266f [file] [log] [blame]
// 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.
#include <setjmp.h> // NOLINT
#include <stdlib.h>
#include "vm/globals.h"
#if defined(TARGET_ARCH_ARM64)
// Only build the simulator if not compiling for real ARM hardware.
#if defined(USING_SIMULATOR)
#include "vm/simulator.h"
#include "vm/compiler/assembler/assembler.h"
#include "vm/compiler/assembler/disassembler.h"
#include "vm/constants_arm64.h"
#include "vm/native_arguments.h"
#include "vm/os_thread.h"
#include "vm/stack_frame.h"
namespace dart {
DEFINE_FLAG(uint64_t,
trace_sim_after,
ULLONG_MAX,
"Trace simulator execution after instruction count reached.");
DEFINE_FLAG(uint64_t,
stop_sim_at,
ULLONG_MAX,
"Instruction address or instruction count to stop simulator at.");
// This macro provides a platform independent use of sscanf. The reason for
// SScanF not being implemented in a platform independent way through
// OS in the same way as SNPrint is that the Windows C Run-Time
// Library does not provide vsscanf.
#define SScanF sscanf // NOLINT
// SimulatorSetjmpBuffer are linked together, and the last created one
// is referenced by the Simulator. When an exception is thrown, the exception
// runtime looks at where to jump and finds the corresponding
// SimulatorSetjmpBuffer based on the stack pointer of the exception handler.
// The runtime then does a Longjmp on that buffer to return to the simulator.
class SimulatorSetjmpBuffer {
public:
void Longjmp() {
// "This" is now the last setjmp buffer.
simulator_->set_last_setjmp_buffer(this);
longjmp(buffer_, 1);
}
explicit SimulatorSetjmpBuffer(Simulator* sim) {
simulator_ = sim;
link_ = sim->last_setjmp_buffer();
sim->set_last_setjmp_buffer(this);
sp_ = static_cast<uword>(sim->get_register(R31, R31IsSP));
}
~SimulatorSetjmpBuffer() {
ASSERT(simulator_->last_setjmp_buffer() == this);
simulator_->set_last_setjmp_buffer(link_);
}
SimulatorSetjmpBuffer* link() { return link_; }
uword sp() { return sp_; }
private:
uword sp_;
Simulator* simulator_;
SimulatorSetjmpBuffer* link_;
jmp_buf buffer_;
friend class Simulator;
};
// The SimulatorDebugger class is used by the simulator while debugging
// simulated ARM64 code.
class SimulatorDebugger {
public:
explicit SimulatorDebugger(Simulator* sim);
~SimulatorDebugger();
void Stop(Instr* instr, const char* message);
void Debug();
char* ReadLine(const char* prompt);
private:
Simulator* sim_;
bool GetValue(char* desc, uint64_t* value);
bool GetSValue(char* desc, uint32_t* value);
bool GetDValue(char* desc, uint64_t* value);
bool GetQValue(char* desc, simd_value_t* value);
static TokenPosition GetApproximateTokenIndex(const Code& code, uword pc);
static void PrintDartFrame(uword pc,
uword fp,
uword sp,
const Function& function,
TokenPosition token_pos,
bool is_optimized,
bool is_inlined);
void PrintBacktrace();
// Set or delete a breakpoint. Returns true if successful.
bool SetBreakpoint(Instr* breakpc);
bool DeleteBreakpoint(Instr* breakpc);
// Undo and redo all breakpoints. This is needed to bracket disassembly and
// execution to skip past breakpoints when run from the debugger.
void UndoBreakpoints();
void RedoBreakpoints();
};
SimulatorDebugger::SimulatorDebugger(Simulator* sim) {
sim_ = sim;
}
SimulatorDebugger::~SimulatorDebugger() {}
void SimulatorDebugger::Stop(Instr* instr, const char* message) {
OS::PrintErr("Simulator hit %s\n", message);
Debug();
}
static Register LookupCpuRegisterByName(const char* name) {
static const char* kNames[] = {
"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
"r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
"r24", "r25", "r26", "r27", "r28", "r29", "r30",
"ip0", "ip1", "pp", "fp", "lr", "sp", "zr",
};
static const Register kRegisters[] = {
R0, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10,
R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21,
R22, R23, R24, R25, R26, R27, R28, R29, R30,
IP0, IP1, PP, FP, LR, R31, ZR,
};
ASSERT(ARRAY_SIZE(kNames) == ARRAY_SIZE(kRegisters));
for (unsigned i = 0; i < ARRAY_SIZE(kNames); i++) {
if (strcmp(kNames[i], name) == 0) {
return kRegisters[i];
}
}
return kNoRegister;
}
static VRegister LookupVRegisterByName(const char* name) {
int reg_nr = -1;
bool ok = SScanF(name, "v%d", &reg_nr);
if (ok && (0 <= reg_nr) && (reg_nr < kNumberOfVRegisters)) {
return static_cast<VRegister>(reg_nr);
}
return kNoVRegister;
}
bool SimulatorDebugger::GetValue(char* desc, uint64_t* value) {
Register reg = LookupCpuRegisterByName(desc);
if (reg != kNoRegister) {
if (reg == ZR) {
*value = 0;
return true;
}
*value = sim_->get_register(reg);
return true;
}
if (desc[0] == '*') {
uint64_t addr;
if (GetValue(desc + 1, &addr)) {
if (Simulator::IsIllegalAddress(addr)) {
return false;
}
*value = *(reinterpret_cast<int64_t*>(addr));
return true;
}
}
if (strcmp("pc", desc) == 0) {
*value = sim_->get_pc();
return true;
}
bool retval = SScanF(desc, "0x%" Px64, value) == 1;
if (!retval) {
retval = SScanF(desc, "%" Px64, value) == 1;
}
return retval;
}
bool SimulatorDebugger::GetSValue(char* desc, uint32_t* value) {
VRegister vreg = LookupVRegisterByName(desc);
if (vreg != kNoVRegister) {
*value = sim_->get_vregisters(vreg, 0);
return true;
}
if (desc[0] == '*') {
uint64_t addr;
if (GetValue(desc + 1, &addr)) {
if (Simulator::IsIllegalAddress(addr)) {
return false;
}
*value = *(reinterpret_cast<uint32_t*>(addr));
return true;
}
}
return false;
}
bool SimulatorDebugger::GetDValue(char* desc, uint64_t* value) {
VRegister vreg = LookupVRegisterByName(desc);
if (vreg != kNoVRegister) {
*value = sim_->get_vregisterd(vreg, 0);
return true;
}
if (desc[0] == '*') {
uint64_t addr;
if (GetValue(desc + 1, &addr)) {
if (Simulator::IsIllegalAddress(addr)) {
return false;
}
*value = *(reinterpret_cast<uint64_t*>(addr));
return true;
}
}
return false;
}
bool SimulatorDebugger::GetQValue(char* desc, simd_value_t* value) {
VRegister vreg = LookupVRegisterByName(desc);
if (vreg != kNoVRegister) {
sim_->get_vregister(vreg, value);
return true;
}
if (desc[0] == '*') {
uint64_t addr;
if (GetValue(desc + 1, &addr)) {
if (Simulator::IsIllegalAddress(addr)) {
return false;
}
*value = *(reinterpret_cast<simd_value_t*>(addr));
return true;
}
}
return false;
}
TokenPosition SimulatorDebugger::GetApproximateTokenIndex(const Code& code,
uword pc) {
TokenPosition token_pos = TokenPosition::kNoSource;
uword pc_offset = pc - code.PayloadStart();
const PcDescriptors& descriptors =
PcDescriptors::Handle(code.pc_descriptors());
PcDescriptors::Iterator iter(descriptors, RawPcDescriptors::kAnyKind);
while (iter.MoveNext()) {
if (iter.PcOffset() == pc_offset) {
return iter.TokenPos();
} else if (!token_pos.IsReal() && (iter.PcOffset() > pc_offset)) {
token_pos = iter.TokenPos();
}
}
return token_pos;
}
void SimulatorDebugger::PrintDartFrame(uword pc,
uword fp,
uword sp,
const Function& function,
TokenPosition token_pos,
bool is_optimized,
bool is_inlined) {
const Script& script = Script::Handle(function.script());
const String& func_name = String::Handle(function.QualifiedScrubbedName());
const String& url = String::Handle(script.url());
intptr_t line = -1;
intptr_t column = -1;
if (token_pos.IsReal()) {
script.GetTokenLocation(token_pos, &line, &column);
}
OS::PrintErr(
"pc=0x%" Px " fp=0x%" Px " sp=0x%" Px " %s%s (%s:%" Pd ":%" Pd ")\n", pc,
fp, sp, is_optimized ? (is_inlined ? "inlined " : "optimized ") : "",
func_name.ToCString(), url.ToCString(), line, column);
}
void SimulatorDebugger::PrintBacktrace() {
StackFrameIterator frames(
sim_->get_register(FP), sim_->get_register(SP), sim_->get_pc(),
ValidationPolicy::kDontValidateFrames, Thread::Current(),
StackFrameIterator::kNoCrossThreadIteration);
StackFrame* frame = frames.NextFrame();
ASSERT(frame != NULL);
Function& function = Function::Handle();
Function& inlined_function = Function::Handle();
Code& code = Code::Handle();
Code& unoptimized_code = Code::Handle();
while (frame != NULL) {
if (frame->IsDartFrame()) {
ASSERT(!frame->is_interpreted()); // Not yet supported.
code = frame->LookupDartCode();
function = code.function();
if (code.is_optimized()) {
// For optimized frames, extract all the inlined functions if any
// into the stack trace.
InlinedFunctionsIterator it(code, frame->pc());
while (!it.Done()) {
// Print each inlined frame with its pc in the corresponding
// unoptimized frame.
inlined_function = it.function();
unoptimized_code = it.code();
uword unoptimized_pc = it.pc();
it.Advance();
if (!it.Done()) {
PrintDartFrame(
unoptimized_pc, frame->fp(), frame->sp(), inlined_function,
GetApproximateTokenIndex(unoptimized_code, unoptimized_pc),
true, true);
}
}
// Print the optimized inlining frame below.
}
PrintDartFrame(frame->pc(), frame->fp(), frame->sp(), function,
GetApproximateTokenIndex(code, frame->pc()),
code.is_optimized(), false);
} else {
OS::PrintErr("pc=0x%" Px " fp=0x%" Px " sp=0x%" Px " %s frame\n",
frame->pc(), frame->fp(), frame->sp(),
frame->IsEntryFrame()
? "entry"
: frame->IsExitFrame()
? "exit"
: frame->IsStubFrame() ? "stub" : "invalid");
}
frame = frames.NextFrame();
}
}
bool SimulatorDebugger::SetBreakpoint(Instr* breakpc) {
// Check if a breakpoint can be set. If not return without any side-effects.
if (sim_->break_pc_ != NULL) {
return false;
}
// Set the breakpoint.
sim_->break_pc_ = breakpc;
sim_->break_instr_ = breakpc->InstructionBits();
// Not setting the breakpoint instruction in the code itself. It will be set
// when the debugger shell continues.
return true;
}
bool SimulatorDebugger::DeleteBreakpoint(Instr* breakpc) {
if (sim_->break_pc_ != NULL) {
sim_->break_pc_->SetInstructionBits(sim_->break_instr_);
}
sim_->break_pc_ = NULL;
sim_->break_instr_ = 0;
return true;
}
void SimulatorDebugger::UndoBreakpoints() {
if (sim_->break_pc_ != NULL) {
sim_->break_pc_->SetInstructionBits(sim_->break_instr_);
}
}
void SimulatorDebugger::RedoBreakpoints() {
if (sim_->break_pc_ != NULL) {
sim_->break_pc_->SetInstructionBits(Instr::kSimulatorBreakpointInstruction);
}
}
void SimulatorDebugger::Debug() {
intptr_t last_pc = -1;
bool done = false;
#define COMMAND_SIZE 63
#define ARG_SIZE 255
#define STR(a) #a
#define XSTR(a) STR(a)
char cmd[COMMAND_SIZE + 1];
char arg1[ARG_SIZE + 1];
char arg2[ARG_SIZE + 1];
// make sure to have a proper terminating character if reaching the limit
cmd[COMMAND_SIZE] = 0;
arg1[ARG_SIZE] = 0;
arg2[ARG_SIZE] = 0;
// Undo all set breakpoints while running in the debugger shell. This will
// make them invisible to all commands.
UndoBreakpoints();
while (!done) {
if (last_pc != sim_->get_pc()) {
last_pc = sim_->get_pc();
if (Simulator::IsIllegalAddress(last_pc)) {
OS::PrintErr("pc is out of bounds: 0x%" Px "\n", last_pc);
} else {
if (FLAG_support_disassembler) {
Disassembler::Disassemble(last_pc, last_pc + Instr::kInstrSize);
} else {
OS::PrintErr("Disassembler not supported in this mode.\n");
}
}
}
char* line = ReadLine("sim> ");
if (line == NULL) {
FATAL("ReadLine failed");
} else {
// Use sscanf to parse the individual parts of the command line. At the
// moment no command expects more than two parameters.
int args = SScanF(line,
"%" XSTR(COMMAND_SIZE) "s "
"%" XSTR(ARG_SIZE) "s "
"%" XSTR(ARG_SIZE) "s",
cmd, arg1, arg2);
if ((strcmp(cmd, "h") == 0) || (strcmp(cmd, "help") == 0)) {
OS::PrintErr(
"c/cont -- continue execution\n"
"disasm -- disassemble instrs at current pc location\n"
" other variants are:\n"
" disasm <address>\n"
" disasm <address> <number_of_instructions>\n"
" by default 10 instrs are disassembled\n"
"del -- delete breakpoints\n"
"flags -- print flag values\n"
"gdb -- transfer control to gdb\n"
"h/help -- print this help string\n"
"break <address> -- set break point at specified address\n"
"p/print <reg or icount or value or *addr> -- print integer\n"
"pf/printfloat <vreg or *addr> --print float value\n"
"pd/printdouble <vreg or *addr> -- print double value\n"
"pq/printquad <vreg or *addr> -- print vector register\n"
"po/printobject <*reg or *addr> -- print object\n"
"si/stepi -- single step an instruction\n"
"trace -- toggle execution tracing mode\n"
"bt -- print backtrace\n"
"unstop -- if current pc is a stop instr make it a nop\n"
"q/quit -- Quit the debugger and exit the program\n");
} else if ((strcmp(cmd, "quit") == 0) || (strcmp(cmd, "q") == 0)) {
OS::PrintErr("Quitting\n");
OS::Exit(0);
} else if ((strcmp(cmd, "si") == 0) || (strcmp(cmd, "stepi") == 0)) {
sim_->InstructionDecode(reinterpret_cast<Instr*>(sim_->get_pc()));
} else if ((strcmp(cmd, "c") == 0) || (strcmp(cmd, "cont") == 0)) {
// Execute the one instruction we broke at with breakpoints disabled.
sim_->InstructionDecode(reinterpret_cast<Instr*>(sim_->get_pc()));
// Leave the debugger shell.
done = true;
} else if ((strcmp(cmd, "p") == 0) || (strcmp(cmd, "print") == 0)) {
if (args == 2) {
uint64_t value;
if (strcmp(arg1, "icount") == 0) {
value = sim_->get_icount();
OS::PrintErr("icount: %" Pu64 " 0x%" Px64 "\n", value, value);
} else if (GetValue(arg1, &value)) {
OS::PrintErr("%s: %" Pu64 " 0x%" Px64 "\n", arg1, value, value);
} else {
OS::PrintErr("%s unrecognized\n", arg1);
}
} else {
OS::PrintErr("print <reg or icount or value or *addr>\n");
}
} else if ((strcmp(cmd, "pf") == 0) || (strcmp(cmd, "printfloat") == 0)) {
if (args == 2) {
uint32_t value;
if (GetSValue(arg1, &value)) {
float svalue = bit_cast<float, uint32_t>(value);
OS::PrintErr("%s: %d 0x%x %.8g\n", arg1, value, value, svalue);
} else {
OS::PrintErr("%s unrecognized\n", arg1);
}
} else {
OS::PrintErr("printfloat <vreg or *addr>\n");
}
} else if ((strcmp(cmd, "pd") == 0) ||
(strcmp(cmd, "printdouble") == 0)) {
if (args == 2) {
uint64_t long_value;
if (GetDValue(arg1, &long_value)) {
double dvalue = bit_cast<double, uint64_t>(long_value);
OS::PrintErr("%s: %" Pu64 " 0x%" Px64 " %.8g\n", arg1, long_value,
long_value, dvalue);
} else {
OS::PrintErr("%s unrecognized\n", arg1);
}
} else {
OS::PrintErr("printdouble <vreg or *addr>\n");
}
} else if ((strcmp(cmd, "pq") == 0) || (strcmp(cmd, "printquad") == 0)) {
if (args == 2) {
simd_value_t quad_value;
if (GetQValue(arg1, &quad_value)) {
const int64_t d0 = quad_value.bits.i64[0];
const int64_t d1 = quad_value.bits.i64[1];
const double dval0 = bit_cast<double, int64_t>(d0);
const double dval1 = bit_cast<double, int64_t>(d1);
const int32_t s0 = quad_value.bits.i32[0];
const int32_t s1 = quad_value.bits.i32[1];
const int32_t s2 = quad_value.bits.i32[2];
const int32_t s3 = quad_value.bits.i32[3];
const float sval0 = bit_cast<float, int32_t>(s0);
const float sval1 = bit_cast<float, int32_t>(s1);
const float sval2 = bit_cast<float, int32_t>(s2);
const float sval3 = bit_cast<float, int32_t>(s3);
OS::PrintErr("%s: %" Pu64 " 0x%" Px64 " %.8g\n", arg1, d0, d0,
dval0);
OS::PrintErr("%s: %" Pu64 " 0x%" Px64 " %.8g\n", arg1, d1, d1,
dval1);
OS::PrintErr("%s: %d 0x%x %.8g\n", arg1, s0, s0, sval0);
OS::PrintErr("%s: %d 0x%x %.8g\n", arg1, s1, s1, sval1);
OS::PrintErr("%s: %d 0x%x %.8g\n", arg1, s2, s2, sval2);
OS::PrintErr("%s: %d 0x%x %.8g\n", arg1, s3, s3, sval3);
} else {
OS::PrintErr("%s unrecognized\n", arg1);
}
} else {
OS::PrintErr("printquad <vreg or *addr>\n");
}
} else if ((strcmp(cmd, "po") == 0) ||
(strcmp(cmd, "printobject") == 0)) {
if (args == 2) {
uint64_t value;
// Make the dereferencing '*' optional.
if (((arg1[0] == '*') && GetValue(arg1 + 1, &value)) ||
GetValue(arg1, &value)) {
if (Isolate::Current()->heap()->Contains(value)) {
OS::PrintErr("%s: \n", arg1);
#if defined(DEBUG)
const Object& obj =
Object::Handle(reinterpret_cast<RawObject*>(value));
obj.Print();
#endif // defined(DEBUG)
} else {
OS::PrintErr("0x%" Px64 " is not an object reference\n", value);
}
} else {
OS::PrintErr("%s unrecognized\n", arg1);
}
} else {
OS::PrintErr("printobject <*reg or *addr>\n");
}
} else if (strcmp(cmd, "disasm") == 0) {
uint64_t start = 0;
uint64_t end = 0;
if (args == 1) {
start = sim_->get_pc();
end = start + (10 * Instr::kInstrSize);
} else if (args == 2) {
if (GetValue(arg1, &start)) {
// No length parameter passed, assume 10 instructions.
if (Simulator::IsIllegalAddress(start)) {
// If start isn't a valid address, warn and use PC instead.
OS::PrintErr("First argument yields invalid address: 0x%" Px64
"\n",
start);
OS::PrintErr("Using PC instead\n");
start = sim_->get_pc();
}
end = start + (10 * Instr::kInstrSize);
}
} else {
uint64_t length;
if (GetValue(arg1, &start) && GetValue(arg2, &length)) {
if (Simulator::IsIllegalAddress(start)) {
// If start isn't a valid address, warn and use PC instead.
OS::PrintErr("First argument yields invalid address: 0x%" Px64
"\n",
start);
OS::PrintErr("Using PC instead\n");
start = sim_->get_pc();
}
end = start + (length * Instr::kInstrSize);
}
}
if ((start > 0) && (end > start)) {
if (FLAG_support_disassembler) {
Disassembler::Disassemble(start, end);
} else {
OS::PrintErr("Disassembler not supported in this mode.\n");
}
} else {
OS::PrintErr("disasm [<address> [<number_of_instructions>]]\n");
}
} else if (strcmp(cmd, "gdb") == 0) {
OS::PrintErr("relinquishing control to gdb\n");
OS::DebugBreak();
OS::PrintErr("regaining control from gdb\n");
} else if (strcmp(cmd, "break") == 0) {
if (args == 2) {
uint64_t addr;
if (GetValue(arg1, &addr)) {
if (!SetBreakpoint(reinterpret_cast<Instr*>(addr))) {
OS::PrintErr("setting breakpoint failed\n");
}
} else {
OS::PrintErr("%s unrecognized\n", arg1);
}
} else {
OS::PrintErr("break <addr>\n");
}
} else if (strcmp(cmd, "del") == 0) {
if (!DeleteBreakpoint(NULL)) {
OS::PrintErr("deleting breakpoint failed\n");
}
} else if (strcmp(cmd, "flags") == 0) {
OS::PrintErr("APSR: ");
OS::PrintErr("N flag: %d; ", sim_->n_flag_);
OS::PrintErr("Z flag: %d; ", sim_->z_flag_);
OS::PrintErr("C flag: %d; ", sim_->c_flag_);
OS::PrintErr("V flag: %d\n", sim_->v_flag_);
} else if (strcmp(cmd, "unstop") == 0) {
intptr_t stop_pc = sim_->get_pc() - Instr::kInstrSize;
Instr* stop_instr = reinterpret_cast<Instr*>(stop_pc);
if (stop_instr->IsExceptionGenOp()) {
stop_instr->SetInstructionBits(Instr::kNopInstruction);
} else {
OS::PrintErr("Not at debugger stop.\n");
}
} else if (strcmp(cmd, "trace") == 0) {
if (FLAG_trace_sim_after == ULLONG_MAX) {
FLAG_trace_sim_after = sim_->get_icount();
OS::PrintErr("execution tracing on\n");
} else {
FLAG_trace_sim_after = ULLONG_MAX;
OS::PrintErr("execution tracing off\n");
}
} else if (strcmp(cmd, "bt") == 0) {
PrintBacktrace();
} else {
OS::PrintErr("Unknown command: %s\n", cmd);
}
}
delete[] line;
}
// Add all the breakpoints back to stop execution and enter the debugger
// shell when hit.
RedoBreakpoints();
#undef COMMAND_SIZE
#undef ARG_SIZE
#undef STR
#undef XSTR
}
char* SimulatorDebugger::ReadLine(const char* prompt) {
char* result = NULL;
char line_buf[256];
intptr_t offset = 0;
bool keep_going = true;
OS::PrintErr("%s", prompt);
while (keep_going) {
if (fgets(line_buf, sizeof(line_buf), stdin) == NULL) {
// fgets got an error. Just give up.
if (result != NULL) {
delete[] result;
}
return NULL;
}
intptr_t len = strlen(line_buf);
if (len > 1 && line_buf[len - 2] == '\\' && line_buf[len - 1] == '\n') {
// When we read a line that ends with a "\" we remove the escape and
// append the remainder.
line_buf[len - 2] = '\n';
line_buf[len - 1] = 0;
len -= 1;
} else if ((len > 0) && (line_buf[len - 1] == '\n')) {
// Since we read a new line we are done reading the line. This
// will exit the loop after copying this buffer into the result.
keep_going = false;
}
if (result == NULL) {
// Allocate the initial result and make room for the terminating '\0'
result = new char[len + 1];
if (result == NULL) {
// OOM, so cannot readline anymore.
return NULL;
}
} else {
// Allocate a new result with enough room for the new addition.
intptr_t new_len = offset + len + 1;
char* new_result = new char[new_len];
if (new_result == NULL) {
// OOM, free the buffer allocated so far and return NULL.
delete[] result;
return NULL;
} else {
// Copy the existing input into the new array and set the new
// array as the result.
memmove(new_result, result, offset);
delete[] result;
result = new_result;
}
}
// Copy the newly read line into the result.
memmove(result + offset, line_buf, len);
offset += len;
}
ASSERT(result != NULL);
result[offset] = '\0';
return result;
}
void Simulator::Init() {}
Simulator::Simulator() : exclusive_access_addr_(0), exclusive_access_value_(0) {
// Setup simulator support first. Some of this information is needed to
// setup the architecture state.
// We allocate the stack here, the size is computed as the sum of
// the size specified by the user and the buffer space needed for
// handling stack overflow exceptions. To be safe in potential
// stack underflows we also add some underflow buffer space.
stack_ =
new char[(OSThread::GetSpecifiedStackSize() +
OSThread::kStackSizeBufferMax + kSimulatorStackUnderflowSize)];
// Low address.
stack_limit_ = reinterpret_cast<uword>(stack_);
// Limit for StackOverflowError.
overflow_stack_limit_ = stack_limit_ + OSThread::kStackSizeBufferMax;
// High address.
stack_base_ = overflow_stack_limit_ + OSThread::GetSpecifiedStackSize();
pc_modified_ = false;
icount_ = 0;
break_pc_ = NULL;
break_instr_ = 0;
last_setjmp_buffer_ = NULL;
// Setup architecture state.
// All registers are initialized to zero to start with.
for (int i = 0; i < kNumberOfCpuRegisters; i++) {
registers_[i] = 0;
}
n_flag_ = false;
z_flag_ = false;
c_flag_ = false;
v_flag_ = false;
for (int i = 0; i < kNumberOfVRegisters; i++) {
vregisters_[i].bits.i64[0] = 0;
vregisters_[i].bits.i64[1] = 0;
}
// The sp is initialized to point to the bottom (high address) of the
// allocated stack area.
registers_[R31] = stack_base();
// The lr and pc are initialized to a known bad value that will cause an
// access violation if the simulator ever tries to execute it.
registers_[LR] = kBadLR;
pc_ = kBadLR;
}
Simulator::~Simulator() {
delete[] stack_;
Isolate* isolate = Isolate::Current();
if (isolate != NULL) {
isolate->set_simulator(NULL);
}
}
// When the generated code calls an external reference we need to catch that in
// the simulator. The external reference will be a function compiled for the
// host architecture. We need to call that function instead of trying to
// execute it with the simulator. We do that by redirecting the external
// reference to a svc (supervisor call) instruction that is handled by
// the simulator. We write the original destination of the jump just at a known
// offset from the svc instruction so the simulator knows what to call.
class Redirection {
public:
uword address_of_hlt_instruction() {
return reinterpret_cast<uword>(&hlt_instruction_);
}
uword external_function() const { return external_function_; }
Simulator::CallKind call_kind() const { return call_kind_; }
int argument_count() const { return argument_count_; }
static Redirection* Get(uword external_function,
Simulator::CallKind call_kind,
int argument_count) {
MutexLocker ml(mutex_);
for (Redirection* current = list_; current != NULL;
current = current->next_) {
if (current->external_function_ == external_function) return current;
}
Redirection* redirection =
new Redirection(external_function, call_kind, argument_count);
redirection->next_ = list_;
// Use a memory fence to ensure all pending writes are written at the time
// of updating the list head, so the profiling thread always has a valid
// list to look at.
Redirection* old_head = list_;
Redirection* replaced_list_head =
AtomicOperations::CompareAndSwapPointer<Redirection>(&list_, old_head,
redirection);
ASSERT(old_head == replaced_list_head);
return redirection;
}
static Redirection* FromHltInstruction(Instr* hlt_instruction) {
char* addr_of_hlt = reinterpret_cast<char*>(hlt_instruction);
char* addr_of_redirection =
addr_of_hlt - OFFSET_OF(Redirection, hlt_instruction_);
return reinterpret_cast<Redirection*>(addr_of_redirection);
}
// Please note that this function is called by the signal handler of the
// profiling thread. It can therefore run at any point in time and is not
// allowed to hold any locks - which is precisely the reason why the list is
// prepend-only and a memory fence is used when writing the list head [list_]!
static uword FunctionForRedirect(uword address_of_hlt) {
Redirection* current;
for (current = list_; current != NULL; current = current->next_) {
if (current->address_of_hlt_instruction() == address_of_hlt) {
return current->external_function_;
}
}
return 0;
}
private:
Redirection(uword external_function,
Simulator::CallKind call_kind,
int argument_count)
: external_function_(external_function),
call_kind_(call_kind),
argument_count_(argument_count),
hlt_instruction_(Instr::kSimulatorRedirectInstruction),
next_(NULL) {}
uword external_function_;
Simulator::CallKind call_kind_;
int argument_count_;
uint32_t hlt_instruction_;
Redirection* next_;
static Redirection* list_;
static Mutex* mutex_;
};
Redirection* Redirection::list_ = NULL;
Mutex* Redirection::mutex_ = new Mutex();
uword Simulator::RedirectExternalReference(uword function,
CallKind call_kind,
int argument_count) {
Redirection* redirection =
Redirection::Get(function, call_kind, argument_count);
return redirection->address_of_hlt_instruction();
}
uword Simulator::FunctionForRedirect(uword redirect) {
return Redirection::FunctionForRedirect(redirect);
}
// Get the active Simulator for the current isolate.
Simulator* Simulator::Current() {
Simulator* simulator = Isolate::Current()->simulator();
if (simulator == NULL) {
simulator = new Simulator();
Isolate::Current()->set_simulator(simulator);
}
return simulator;
}
// Sets the register in the architecture state.
void Simulator::set_register(Instr* instr,
Register reg,
int64_t value,
R31Type r31t) {
// Register is in range.
ASSERT((reg >= 0) && (reg < kNumberOfCpuRegisters));
ASSERT(instr == NULL || reg != R18); // R18 is globally reserved on iOS.
if ((reg != R31) || (r31t != R31IsZR)) {
registers_[reg] = value;
// If we're setting CSP, make sure it is 16-byte aligned. In truth, CSP
// can store addresses that are not 16-byte aligned, but loads and stores
// are not allowed through CSP when it is not aligned. Thus, this check is
// more conservative that necessary. However, it will likely be more
// useful to find the program locations where CSP is set to a bad value,
// than to find only the resulting loads/stores that would cause a fault on
// hardware.
if ((instr != NULL) && (reg == R31) && !Utils::IsAligned(value, 16)) {
UnalignedAccess("CSP set", value, instr);
}
}
}
// Get the register from the architecture state.
int64_t Simulator::get_register(Register reg, R31Type r31t) const {
ASSERT((reg >= 0) && (reg < kNumberOfCpuRegisters));
if ((reg == R31) && (r31t == R31IsZR)) {
return 0;
} else {
return registers_[reg];
}
}
void Simulator::set_wregister(Register reg, int32_t value, R31Type r31t) {
ASSERT((reg >= 0) && (reg < kNumberOfCpuRegisters));
// When setting in W mode, clear the high bits.
if ((reg != R31) || (r31t != R31IsZR)) {
registers_[reg] = Utils::LowHighTo64Bits(static_cast<uint32_t>(value), 0);
}
}
// Get the register from the architecture state.
int32_t Simulator::get_wregister(Register reg, R31Type r31t) const {
ASSERT((reg >= 0) && (reg < kNumberOfCpuRegisters));
if ((reg == R31) && (r31t == R31IsZR)) {
return 0;
} else {
return static_cast<int32_t>(registers_[reg]);
}
}
int32_t Simulator::get_vregisters(VRegister reg, int idx) const {
ASSERT((reg >= 0) && (reg < kNumberOfVRegisters));
ASSERT((idx >= 0) && (idx <= 3));
return vregisters_[reg].bits.i32[idx];
}
void Simulator::set_vregisters(VRegister reg, int idx, int32_t value) {
ASSERT((reg >= 0) && (reg < kNumberOfVRegisters));
ASSERT((idx >= 0) && (idx <= 3));
vregisters_[reg].bits.i32[idx] = value;
}
int64_t Simulator::get_vregisterd(VRegister reg, int idx) const {
ASSERT((reg >= 0) && (reg < kNumberOfVRegisters));
ASSERT((idx == 0) || (idx == 1));
return vregisters_[reg].bits.i64[idx];
}
void Simulator::set_vregisterd(VRegister reg, int idx, int64_t value) {
ASSERT((reg >= 0) && (reg < kNumberOfVRegisters));
ASSERT((idx == 0) || (idx == 1));
vregisters_[reg].bits.i64[idx] = value;
}
void Simulator::get_vregister(VRegister reg, simd_value_t* value) const {
ASSERT((reg >= 0) && (reg < kNumberOfVRegisters));
value->bits.i64[0] = vregisters_[reg].bits.i64[0];
value->bits.i64[1] = vregisters_[reg].bits.i64[1];
}
void Simulator::set_vregister(VRegister reg, const simd_value_t& value) {
ASSERT((reg >= 0) && (reg < kNumberOfVRegisters));
vregisters_[reg].bits.i64[0] = value.bits.i64[0];
vregisters_[reg].bits.i64[1] = value.bits.i64[1];
}
// Raw access to the PC register.
void Simulator::set_pc(int64_t value) {
pc_modified_ = true;
last_pc_ = pc_;
pc_ = value;
}
// Raw access to the pc.
int64_t Simulator::get_pc() const {
return pc_;
}
int64_t Simulator::get_last_pc() const {
return last_pc_;
}
void Simulator::HandleIllegalAccess(uword addr, Instr* instr) {
uword fault_pc = get_pc();
uword last_pc = get_last_pc();
char buffer[128];
snprintf(buffer, sizeof(buffer),
"illegal memory access at 0x%" Px ", pc=0x%" Px ", last_pc=0x%" Px
"\n",
addr, fault_pc, last_pc);
SimulatorDebugger dbg(this);
dbg.Stop(instr, buffer);
// The debugger will return control in non-interactive mode.
FATAL("Cannot continue execution after illegal memory access.");
}
// The ARMv8 manual advises that an unaligned access may generate a fault,
// and if not, will likely take a number of additional cycles to execute,
// so let's just not generate any.
void Simulator::UnalignedAccess(const char* msg, uword addr, Instr* instr) {
char buffer[128];
snprintf(buffer, sizeof(buffer), "unaligned %s at 0x%" Px ", pc=%p\n", msg,
addr, instr);
SimulatorDebugger dbg(this);
dbg.Stop(instr, buffer);
// The debugger will not be able to single step past this instruction, but
// it will be possible to disassemble the code and inspect registers.
FATAL("Cannot continue execution after unaligned access.");
}
void Simulator::UnimplementedInstruction(Instr* instr) {
char buffer[128];
snprintf(buffer, sizeof(buffer),
"Unimplemented instruction: at %p, last_pc=0x%" Px64 "\n", instr,
get_last_pc());
SimulatorDebugger dbg(this);
dbg.Stop(instr, buffer);
FATAL("Cannot continue execution after unimplemented instruction.");
}
bool Simulator::IsTracingExecution() const {
return icount_ > FLAG_trace_sim_after;
}
intptr_t Simulator::ReadX(uword addr, Instr* instr) {
if ((addr & 7) == 0) {
intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
return *ptr;
}
UnalignedAccess("read", addr, instr);
return 0;
}
void Simulator::WriteX(uword addr, intptr_t value, Instr* instr) {
if ((addr & 7) == 0) {
intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
*ptr = value;
return;
}
UnalignedAccess("write", addr, instr);
}
uint32_t Simulator::ReadWU(uword addr, Instr* instr) {
if ((addr & 3) == 0) {
uint32_t* ptr = reinterpret_cast<uint32_t*>(addr);
return *ptr;
}
UnalignedAccess("read unsigned single word", addr, instr);
return 0;
}
int32_t Simulator::ReadW(uword addr, Instr* instr) {
if ((addr & 3) == 0) {
int32_t* ptr = reinterpret_cast<int32_t*>(addr);
return *ptr;
}
UnalignedAccess("read single word", addr, instr);
return 0;
}
void Simulator::WriteW(uword addr, uint32_t value, Instr* instr) {
if ((addr & 3) == 0) {
uint32_t* ptr = reinterpret_cast<uint32_t*>(addr);
*ptr = value;
return;
}
UnalignedAccess("write single word", addr, instr);
}
uint16_t Simulator::ReadHU(uword addr, Instr* instr) {
if ((addr & 1) == 0) {
uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
return *ptr;
}
UnalignedAccess("unsigned halfword read", addr, instr);
return 0;
}
int16_t Simulator::ReadH(uword addr, Instr* instr) {
if ((addr & 1) == 0) {
int16_t* ptr = reinterpret_cast<int16_t*>(addr);
return *ptr;
}
UnalignedAccess("signed halfword read", addr, instr);
return 0;
}
void Simulator::WriteH(uword addr, uint16_t value, Instr* instr) {
if ((addr & 1) == 0) {
uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
*ptr = value;
return;
}
UnalignedAccess("halfword write", addr, instr);
}
uint8_t Simulator::ReadBU(uword addr) {
uint8_t* ptr = reinterpret_cast<uint8_t*>(addr);
return *ptr;
}
int8_t Simulator::ReadB(uword addr) {
int8_t* ptr = reinterpret_cast<int8_t*>(addr);
return *ptr;
}
void Simulator::WriteB(uword addr, uint8_t value) {
uint8_t* ptr = reinterpret_cast<uint8_t*>(addr);
*ptr = value;
}
void Simulator::ClearExclusive() {
exclusive_access_addr_ = 0;
exclusive_access_value_ = 0;
}
intptr_t Simulator::ReadExclusiveX(uword addr, Instr* instr) {
exclusive_access_addr_ = addr;
exclusive_access_value_ = ReadX(addr, instr);
return exclusive_access_value_;
}
intptr_t Simulator::ReadExclusiveW(uword addr, Instr* instr) {
exclusive_access_addr_ = addr;
exclusive_access_value_ = ReadWU(addr, instr);
return exclusive_access_value_;
}
intptr_t Simulator::WriteExclusiveX(uword addr, intptr_t value, Instr* instr) {
// In a well-formed code store-exclusive instruction should always follow
// a corresponding load-exclusive instruction with the same address.
ASSERT((exclusive_access_addr_ == 0) || (exclusive_access_addr_ == addr));
if (exclusive_access_addr_ != addr) {
return 1; // Failure.
}
uword old_value = exclusive_access_value_;
ClearExclusive();
if (AtomicOperations::CompareAndSwapWord(reinterpret_cast<uword*>(addr),
old_value, value) == old_value) {
return 0; // Success.
}
return 1; // Failure.
}
intptr_t Simulator::WriteExclusiveW(uword addr, intptr_t value, Instr* instr) {
// In a well-formed code store-exclusive instruction should always follow
// a corresponding load-exclusive instruction with the same address.
ASSERT((exclusive_access_addr_ == 0) || (exclusive_access_addr_ == addr));
if (exclusive_access_addr_ != addr) {
return 1; // Failure.
}
uint32_t old_value = static_cast<uint32_t>(exclusive_access_value_);
ClearExclusive();
if (AtomicOperations::CompareAndSwapUint32(reinterpret_cast<uint32_t*>(addr),
old_value, value) == old_value) {
return 0; // Success.
}
return 1; // Failure.
}
// Unsupported instructions use Format to print an error and stop execution.
void Simulator::Format(Instr* instr, const char* format) {
OS::PrintErr("Simulator found unsupported instruction:\n 0x%p: %s\n", instr,
format);
UNIMPLEMENTED();
}
// Calculate and set the Negative and Zero flags.
void Simulator::SetNZFlagsW(int32_t val) {
n_flag_ = (val < 0);
z_flag_ = (val == 0);
}
// Calculate C flag value for additions (and subtractions with adjusted args).
bool Simulator::CarryFromW(int32_t left, int32_t right, int32_t carry) {
uint64_t uleft = static_cast<uint32_t>(left);
uint64_t uright = static_cast<uint32_t>(right);
uint64_t ucarry = static_cast<uint32_t>(carry);
return ((uleft + uright + ucarry) >> 32) != 0;
}
// Calculate V flag value for additions (and subtractions with adjusted args).
bool Simulator::OverflowFromW(int32_t left, int32_t right, int32_t carry) {
int64_t result = static_cast<int64_t>(left) + right + carry;
return (result >> 31) != (result >> 32);
}
// Calculate and set the Negative and Zero flags.
void Simulator::SetNZFlagsX(int64_t val) {
n_flag_ = (val < 0);
z_flag_ = (val == 0);
}
// Calculate C flag value for additions and subtractions.
bool Simulator::CarryFromX(int64_t alu_out,
int64_t left,
int64_t right,
bool addition) {
if (addition) {
return (((left & right) | ((left | right) & ~alu_out)) >> 63) != 0;
} else {
return (((~left & right) | ((~left | right) & alu_out)) >> 63) == 0;
}
}
// Calculate V flag value for additions and subtractions.
bool Simulator::OverflowFromX(int64_t alu_out,
int64_t left,
int64_t right,
bool addition) {
if (addition) {
return (((alu_out ^ left) & (alu_out ^ right)) >> 63) != 0;
} else {
return (((left ^ right) & (alu_out ^ left)) >> 63) != 0;
}
}
// Set the Carry flag.
void Simulator::SetCFlag(bool val) {
c_flag_ = val;
}
// Set the oVerflow flag.
void Simulator::SetVFlag(bool val) {
v_flag_ = val;
}
void Simulator::DecodeMoveWide(Instr* instr) {
const Register rd = instr->RdField();
const int hw = instr->HWField();
const int64_t shift = hw << 4;
const int64_t shifted_imm = static_cast<int64_t>(instr->Imm16Field())
<< shift;
if (instr->SFField()) {
if (instr->Bits(29, 2) == 0) {
// Format(instr, "movn'sf 'rd, 'imm16 'hw");
set_register(instr, rd, ~shifted_imm, instr->RdMode());
} else if (instr->Bits(29, 2) == 2) {
// Format(instr, "movz'sf 'rd, 'imm16 'hw");
set_register(instr, rd, shifted_imm, instr->RdMode());
} else if (instr->Bits(29, 2) == 3) {
// Format(instr, "movk'sf 'rd, 'imm16 'hw");
const int64_t rd_val = get_register(rd, instr->RdMode());
const int64_t result = (rd_val & ~(0xffffL << shift)) | shifted_imm;
set_register(instr, rd, result, instr->RdMode());
} else {
UnimplementedInstruction(instr);
}
} else if ((hw & 0x2) == 0) {
if (instr->Bits(29, 2) == 0) {
// Format(instr, "movn'sf 'rd, 'imm16 'hw");
set_wregister(rd, ~shifted_imm & kWRegMask, instr->RdMode());
} else if (instr->Bits(29, 2) == 2) {
// Format(instr, "movz'sf 'rd, 'imm16 'hw");
set_wregister(rd, shifted_imm & kWRegMask, instr->RdMode());
} else if (instr->Bits(29, 2) == 3) {
// Format(instr, "movk'sf 'rd, 'imm16 'hw");
const int32_t rd_val = get_wregister(rd, instr->RdMode());
const int32_t result = (rd_val & ~(0xffffL << shift)) | shifted_imm;
set_wregister(rd, result, instr->RdMode());
} else {
UnimplementedInstruction(instr);
}
} else {
// Dest is 32 bits, but shift is more than 32.
UnimplementedInstruction(instr);
}
}
void Simulator::DecodeAddSubImm(Instr* instr) {
const bool addition = (instr->Bit(30) == 0);
// Format(instr, "addi'sf's 'rd, 'rn, 'imm12s");
// Format(instr, "subi'sf's 'rd, 'rn, 'imm12s");
const Register rd = instr->RdField();
const Register rn = instr->RnField();
uint32_t imm = (instr->Bit(22) == 1) ? (instr->Imm12Field() << 12)
: (instr->Imm12Field());
if (instr->SFField()) {
// 64-bit add.
const int64_t rn_val = get_register(rn, instr->RnMode());
const int64_t alu_out = addition ? (rn_val + imm) : (rn_val - imm);
set_register(instr, rd, alu_out, instr->RdMode());
if (instr->HasS()) {
SetNZFlagsX(alu_out);
SetCFlag(CarryFromX(alu_out, rn_val, imm, addition));
SetVFlag(OverflowFromX(alu_out, rn_val, imm, addition));
}
} else {
// 32-bit add.
const int32_t rn_val = get_wregister(rn, instr->RnMode());
int32_t carry_in = 0;
if (!addition) {
carry_in = 1;
imm = ~imm;
}
const int32_t alu_out = rn_val + imm + carry_in;
set_wregister(rd, alu_out, instr->RdMode());
if (instr->HasS()) {
SetNZFlagsW(alu_out);
SetCFlag(CarryFromW(rn_val, imm, carry_in));
SetVFlag(OverflowFromW(rn_val, imm, carry_in));
}
}
}
void Simulator::DecodeBitfield(Instr* instr) {
int bitwidth = instr->SFField() == 0 ? 32 : 64;
unsigned op = instr->Bits(29, 2);
ASSERT(op <= 2);
bool sign_extend = op == 0;
bool zero_extend = op == 2;
ASSERT(instr->NField() == instr->SFField());
const Register rn = instr->RnField();
const Register rd = instr->RdField();
int64_t result = get_register(rn, instr->RnMode());
int r_bit = instr->ImmRField();
int s_bit = instr->ImmSField();
result &= Utils::NBitMask(bitwidth);
ASSERT(s_bit < bitwidth && r_bit < bitwidth);
// See ARM v8 Instruction set overview 5.4.5.
// If s >= r then Rd[s-r:0] := Rn[s:r], else Rd[bitwidth+s-r:bitwidth-r] :=
// Rn[s:0].
uword mask = Utils::NBitMask(s_bit + 1);
if (s_bit >= r_bit) {
mask >>= r_bit;
result >>= r_bit;
} else {
result <<= bitwidth - r_bit;
mask <<= bitwidth - r_bit;
}
result &= mask;
if (sign_extend) {
int highest_bit = (s_bit - r_bit) & (bitwidth - 1);
int shift = bitwidth - highest_bit - 1;
result <<= shift;
result = static_cast<word>(result) >> shift;
} else if (!zero_extend) {
const int64_t rd_val = get_register(rd, instr->RnMode());
result |= rd_val & ~mask;
}
if (bitwidth == 64) {
set_register(instr, rd, result, instr->RdMode());
} else {
set_wregister(rd, result, instr->RdMode());
}
}
void Simulator::DecodeLogicalImm(Instr* instr) {
const int op = instr->Bits(29, 2);
const bool set_flags = op == 3;
const int out_size = ((instr->SFField() == 0) && (instr->NField() == 0))
? kWRegSizeInBits
: kXRegSizeInBits;
const Register rn = instr->RnField();
const Register rd = instr->RdField();
const int64_t rn_val = get_register(rn, instr->RnMode());
const uint64_t imm = instr->ImmLogical();
if (imm == 0) {
UnimplementedInstruction(instr);
}
int64_t alu_out = 0;
switch (op) {
case 0:
alu_out = rn_val & imm;
break;
case 1:
alu_out = rn_val | imm;
break;
case 2:
alu_out = rn_val ^ imm;
break;
case 3:
alu_out = rn_val & imm;
break;
default:
UNREACHABLE();
break;
}
if (set_flags) {
if (out_size == kXRegSizeInBits) {
SetNZFlagsX(alu_out);
} else {
SetNZFlagsW(alu_out);
}
SetCFlag(false);
SetVFlag(false);
}
if (out_size == kXRegSizeInBits) {
set_register(instr, rd, alu_out, instr->RdMode());
} else {
set_wregister(rd, alu_out, instr->RdMode());
}
}
void Simulator::DecodePCRel(Instr* instr) {
const int op = instr->Bit(31);
if (op == 0) {
// Format(instr, "adr 'rd, 'pcrel")
const Register rd = instr->RdField();
const int64_t immhi = instr->SImm19Field();
const int64_t immlo = instr->Bits(29, 2);
const int64_t off = (immhi << 2) | immlo;
const int64_t dest = get_pc() + off;
set_register(instr, rd, dest, instr->RdMode());
} else {
UnimplementedInstruction(instr);
}
}
void Simulator::DecodeDPImmediate(Instr* instr) {
if (instr->IsMoveWideOp()) {
DecodeMoveWide(instr);
} else if (instr->IsAddSubImmOp()) {
DecodeAddSubImm(instr);
} else if (instr->IsBitfieldOp()) {
DecodeBitfield(instr);
} else if (instr->IsLogicalImmOp()) {
DecodeLogicalImm(instr);
} else if (instr->IsPCRelOp()) {
DecodePCRel(instr);
} else {
UnimplementedInstruction(instr);
}
}
void Simulator::DecodeCompareAndBranch(Instr* instr) {
const int op = instr->Bit(24);
const Register rt = instr->RtField();
const int64_t imm19 = instr->SImm19Field();
const int64_t dest = get_pc() + (imm19 << 2);
const int64_t mask = instr->SFField() == 1 ? kXRegMask : kWRegMask;
const int64_t rt_val = get_register(rt, R31IsZR) & mask;
if (op == 0) {
// Format(instr, "cbz'sf 'rt, 'dest19");
if (rt_val == 0) {
set_pc(dest);
}
} else {
// Format(instr, "cbnz'sf 'rt, 'dest19");
if (rt_val != 0) {
set_pc(dest);
}
}
}
bool Simulator::ConditionallyExecute(Instr* instr) {
Condition cond;
if (instr->IsConditionalSelectOp()) {
cond = instr->SelectConditionField();
} else {
cond = instr->ConditionField();
}
switch (cond) {
case EQ:
return z_flag_;
case NE:
return !z_flag_;
case CS:
return c_flag_;
case CC:
return !c_flag_;
case MI:
return n_flag_;
case PL:
return !n_flag_;
case VS:
return v_flag_;
case VC:
return !v_flag_;
case HI:
return c_flag_ && !z_flag_;
case LS:
return !c_flag_ || z_flag_;
case GE:
return n_flag_ == v_flag_;
case LT:
return n_flag_ != v_flag_;
case GT:
return !z_flag_ && (n_flag_ == v_flag_);
case LE:
return z_flag_ || (n_flag_ != v_flag_);
case AL:
return true;
default:
UNREACHABLE();
}
return false;
}
void Simulator::DecodeConditionalBranch(Instr* instr) {
// Format(instr, "b'cond 'dest19");
if ((instr->Bit(24) != 0) || (instr->Bit(4) != 0)) {
UnimplementedInstruction(instr);
}
const int64_t imm19 = instr->SImm19Field();
const int64_t dest = get_pc() + (imm19 << 2);
if (ConditionallyExecute(instr)) {
set_pc(dest);
}
}
// Calls into the Dart runtime are based on this interface.
typedef void (*SimulatorRuntimeCall)(NativeArguments arguments);
// Calls to leaf Dart runtime functions are based on this interface.
typedef int64_t (*SimulatorLeafRuntimeCall)(int64_t r0,
int64_t r1,
int64_t r2,
int64_t r3,
int64_t r4,
int64_t r5,
int64_t r6,
int64_t r7);
// Calls to leaf float Dart runtime functions are based on this interface.
typedef double (*SimulatorLeafFloatRuntimeCall)(double d0,
double d1,
double d2,
double d3,
double d4,
double d5,
double d6,
double d7);
// Calls to native Dart functions are based on this interface.
typedef void (*SimulatorBootstrapNativeCall)(NativeArguments* arguments);
typedef void (*SimulatorNativeCall)(NativeArguments* arguments, uword target);
void Simulator::DoRedirectedCall(Instr* instr) {
SimulatorSetjmpBuffer buffer(this);
if (!setjmp(buffer.buffer_)) {
int64_t saved_lr = get_register(LR);
Redirection* redirection = Redirection::FromHltInstruction(instr);
uword external = redirection->external_function();
if (IsTracingExecution()) {
THR_Print("Call to host function at 0x%" Pd "\n", external);
}
if (redirection->call_kind() == kRuntimeCall) {
NativeArguments* arguments =
reinterpret_cast<NativeArguments*>(get_register(R0));
SimulatorRuntimeCall target =
reinterpret_cast<SimulatorRuntimeCall>(external);
target(*arguments);
// Zap result register from void function.
set_register(instr, R0, icount_);
set_register(instr, R1, icount_);
} else if (redirection->call_kind() == kLeafRuntimeCall) {
ASSERT((0 <= redirection->argument_count()) &&
(redirection->argument_count() <= 8));
SimulatorLeafRuntimeCall target =
reinterpret_cast<SimulatorLeafRuntimeCall>(external);
const int64_t r0 = get_register(R0);
const int64_t r1 = get_register(R1);
const int64_t r2 = get_register(R2);
const int64_t r3 = get_register(R3);
const int64_t r4 = get_register(R4);
const int64_t r5 = get_register(R5);
const int64_t r6 = get_register(R6);
const int64_t r7 = get_register(R7);
const int64_t res = target(r0, r1, r2, r3, r4, r5, r6, r7);
set_register(instr, R0, res); // Set returned result from function.
set_register(instr, R1, icount_); // Zap unused result register.
} else if (redirection->call_kind() == kLeafFloatRuntimeCall) {
ASSERT((0 <= redirection->argument_count()) &&
(redirection->argument_count() <= 8));
SimulatorLeafFloatRuntimeCall target =
reinterpret_cast<SimulatorLeafFloatRuntimeCall>(external);
const double d0 = bit_cast<double, int64_t>(get_vregisterd(V0, 0));
const double d1 = bit_cast<double, int64_t>(get_vregisterd(V1, 0));
const double d2 = bit_cast<double, int64_t>(get_vregisterd(V2, 0));
const double d3 = bit_cast<double, int64_t>(get_vregisterd(V3, 0));
const double d4 = bit_cast<double, int64_t>(get_vregisterd(V4, 0));
const double d5 = bit_cast<double, int64_t>(get_vregisterd(V5, 0));
const double d6 = bit_cast<double, int64_t>(get_vregisterd(V6, 0));
const double d7 = bit_cast<double, int64_t>(get_vregisterd(V7, 0));
const double res = target(d0, d1, d2, d3, d4, d5, d6, d7);
set_vregisterd(V0, 0, bit_cast<int64_t, double>(res));
set_vregisterd(V0, 1, 0);
} else if (redirection->call_kind() == kBootstrapNativeCall) {
ASSERT(redirection->argument_count() == 1);
NativeArguments* arguments;
arguments = reinterpret_cast<NativeArguments*>(get_register(R0));
SimulatorBootstrapNativeCall target =
reinterpret_cast<SimulatorBootstrapNativeCall>(external);
target(arguments);
// Zap result register from void function.
set_register(instr, R0, icount_);
} else {
ASSERT(redirection->call_kind() == kNativeCall);
NativeArguments* arguments;
arguments = reinterpret_cast<NativeArguments*>(get_register(R0));
uword target_func = get_register(R1);
SimulatorNativeCall target =
reinterpret_cast<SimulatorNativeCall>(external);
target(arguments, target_func);
// Zap result register from void function.
set_register(instr, R0, icount_);
set_register(instr, R1, icount_);
}
// Zap caller-saved registers, since the actual runtime call could have
// used them.
set_register(NULL, R2, icount_);
set_register(NULL, R3, icount_);
set_register(NULL, R4, icount_);
set_register(NULL, R5, icount_);
set_register(NULL, R6, icount_);
set_register(NULL, R7, icount_);
set_register(NULL, R8, icount_);
set_register(NULL, R9, icount_);
set_register(NULL, R10, icount_);
set_register(NULL, R11, icount_);
set_register(NULL, R12, icount_);
set_register(NULL, R13, icount_);
set_register(NULL, R14, icount_);
set_register(NULL, R15, icount_);
set_register(NULL, IP0, icount_);
set_register(NULL, IP1, icount_);
set_register(NULL, R18, icount_);
set_register(NULL, LR, icount_);
// TODO(zra): Zap caller-saved fpu registers.
// Return.
set_pc(saved_lr);
} else {
// Coming via long jump from a throw. Continue to exception handler.
}
}
void Simulator::DecodeExceptionGen(Instr* instr) {
if ((instr->Bits(0, 2) == 1) && (instr->Bits(2, 3) == 0) &&
(instr->Bits(21, 3) == 0)) {
// Format(instr, "svc 'imm16");
UnimplementedInstruction(instr);
} else if ((instr->Bits(0, 2) == 0) && (instr->Bits(2, 3) == 0) &&
(instr->Bits(21, 3) == 1)) {
// Format(instr, "brk 'imm16");
SimulatorDebugger dbg(this);
int32_t imm = instr->Imm16Field();
char buffer[32];
snprintf(buffer, sizeof(buffer), "brk #0x%x", imm);
set_pc(get_pc() + Instr::kInstrSize);
dbg.Stop(instr, buffer);
} else if ((instr->Bits(0, 2) == 0) && (instr->Bits(2, 3) == 0) &&
(instr->Bits(21, 3) == 2)) {
// Format(instr, "hlt 'imm16");
uint16_t imm = static_cast<uint16_t>(instr->Imm16Field());
if (imm == Instr::kSimulatorBreakCode) {
SimulatorDebugger dbg(this);
dbg.Stop(instr, "breakpoint");
} else if (imm == Instr::kSimulatorRedirectCode) {
DoRedirectedCall(instr);
} else {
UnimplementedInstruction(instr);
}
} else {
UnimplementedInstruction(instr);
}
}
void Simulator::DecodeSystem(Instr* instr) {
if (instr->InstructionBits() == CLREX) {
// Format(instr, "clrex");
ClearExclusive();
return;
}
if ((instr->Bits(0, 8) == 0x1f) && (instr->Bits(12, 4) == 2) &&
(instr->Bits(16, 3) == 3) && (instr->Bits(19, 2) == 0) &&
(instr->Bit(21) == 0)) {
if (instr->Bits(8, 4) == 0) {
// Format(instr, "nop");
} else {
UnimplementedInstruction(instr);
}
} else {
UnimplementedInstruction(instr);
}
}
void Simulator::DecodeTestAndBranch(Instr* instr) {
const int op = instr->Bit(24);
const int bitpos = instr->Bits(19, 5) | (instr->Bit(31) << 5);
const int64_t imm14 = instr->SImm14Field();
const int64_t dest = get_pc() + (imm14 << 2);
const Register rt = instr->RtField();
const int64_t rt_val = get_register(rt, R31IsZR);
if (op == 0) {
// Format(instr, "tbz'sf 'rt, 'bitpos, 'dest14");
if ((rt_val & (1ll << bitpos)) == 0) {
set_pc(dest);
}
} else {
// Format(instr, "tbnz'sf 'rt, 'bitpos, 'dest14");
if ((rt_val & (1ll << bitpos)) != 0) {
set_pc(dest);
}
}
}
void Simulator::DecodeUnconditionalBranch(Instr* instr) {
const bool link = instr->Bit(31) == 1;
const int64_t imm26 = instr->SImm26Field();
const int64_t dest = get_pc() + (imm26 << 2);
const int64_t ret = get_pc() + Instr::kInstrSize;
set_pc(dest);
if (link) {
set_register(instr, LR, ret);
}
}
void Simulator::DecodeUnconditionalBranchReg(Instr* instr) {
if ((instr->Bits(0, 5) == 0) && (instr->Bits(10, 6) == 0) &&
(instr->Bits(16, 5) == 0x1f)) {
switch (instr->Bits(21, 4)) {
case 0: {
// Format(instr, "br 'rn");
const Register rn = instr->RnField();
const int64_t dest = get_register(rn, instr->RnMode());
set_pc(dest);
break;
}
case 1: {
// Format(instr, "blr 'rn");
const Register rn = instr->RnField();
const int64_t dest = get_register(rn, instr->RnMode());
const int64_t ret = get_pc() + Instr::kInstrSize;
set_pc(dest);
set_register(instr, LR, ret);
break;
}
case 2: {
// Format(instr, "ret 'rn");
const Register rn = instr->RnField();
const int64_t rn_val = get_register(rn, instr->RnMode());
set_pc(rn_val);
break;
}
default:
UnimplementedInstruction(instr);
break;
}
} else {
UnimplementedInstruction(instr);
}
}
void Simulator::DecodeCompareBranch(Instr* instr) {
if (instr->IsCompareAndBranchOp()) {
DecodeCompareAndBranch(instr);
} else if (instr->IsConditionalBranchOp()) {
DecodeConditionalBranch(instr);
} else if (instr->IsExceptionGenOp()) {
DecodeExceptionGen(instr);
} else if (instr->IsSystemOp()) {
DecodeSystem(instr);
} else if (instr->IsTestAndBranchOp()) {
DecodeTestAndBranch(instr);
} else if (instr->IsUnconditionalBranchOp()) {
DecodeUnconditionalBranch(instr);
} else if (instr->IsUnconditionalBranchRegOp()) {
DecodeUnconditionalBranchReg(instr);
} else {
UnimplementedInstruction(instr);
}
}
void Simulator::DecodeLoadStoreReg(Instr* instr) {
// Calculate the address.
const Register rn = instr->RnField();
const Register rt = instr->RtField();
const VRegister vt = instr->VtField();
const int64_t rn_val = get_register(rn, R31IsSP);
const uint32_t size = (instr->Bit(26) == 1)
? ((instr->Bit(23) << 2) | instr->SzField())
: instr->SzField();
uword address = 0;
uword wb_address = 0;
bool wb = false;
if (instr->Bit(24) == 1) {
// addr = rn + scaled unsigned 12-bit immediate offset.
const uint32_t imm12 = static_cast<uint32_t>(instr->Imm12Field());
const uint32_t offset = imm12 << size;
address = rn_val + offset;
} else if (instr->Bits(10, 2) == 0) {
// addr = rn + signed 9-bit immediate offset.
wb = false;
const int64_t offset = static_cast<int64_t>(instr->SImm9Field());
address = rn_val + offset;
wb_address = rn_val;
} else if (instr->Bit(10) == 1) {
// addr = rn + signed 9-bit immediate offset.
wb = true;
const int64_t offset = static_cast<int64_t>(instr->SImm9Field());
if (instr->Bit(11) == 1) {
// Pre-index.
address = rn_val + offset;
wb_address = address;
} else {
// Post-index.
address = rn_val;
wb_address = rn_val + offset;
}
} else if (instr->Bits(10, 2) == 2) {
// addr = rn + (rm EXT optionally scaled by operand instruction size).
const Register rm = instr->RmField();
const Extend ext = instr->ExtendTypeField();
const uint8_t scale = (ext == UXTX) && (instr->Bit(12) == 1) ? size : 0;
const int64_t rm_val = get_register(rm, R31IsZR);
const int64_t offset = ExtendOperand(kXRegSizeInBits, rm_val, ext, scale);
address = rn_val + offset;
} else {
UnimplementedInstruction(instr);
return;
}
// Check the address.
if (IsIllegalAddress(address)) {
HandleIllegalAccess(address, instr);
return;
}
// Do access.
if (instr->Bit(26) == 1) {
if (instr->Bit(22) == 0) {
// Format(instr, "fstr'fsz 'vt, 'memop");
const int64_t vt_val = get_vregisterd(vt, 0);
switch (size) {
case 2:
WriteW(address, vt_val & kWRegMask, instr);
break;
case 3:
WriteX(address, vt_val, instr);
break;
case 4: {
simd_value_t val;
get_vregister(vt, &val);
WriteX(address, val.bits.i64[0], instr);
WriteX(address + kWordSize, val.bits.i64[1], instr);
break;
}
default:
UnimplementedInstruction(instr);
return;
}
} else {
// Format(instr, "fldr'fsz 'vt, 'memop");
switch (size) {
case 2:
set_vregisterd(vt, 0, static_cast<int64_t>(ReadWU(address, instr)));
set_vregisterd(vt, 1, 0);
break;
case 3:
set_vregisterd(vt, 0, ReadX(address, instr));
set_vregisterd(vt, 1, 0);
break;
case 4: {
simd_value_t val;
val.bits.i64[0] = ReadX(address, instr);
val.bits.i64[1] = ReadX(address + kWordSize, instr);
set_vregister(vt, val);
break;
}
default:
UnimplementedInstruction(instr);
return;
}
}
} else {
if (instr->Bits(22, 2) == 0) {
// Format(instr, "str'sz 'rt, 'memop");
const int32_t rt_val32 = get_wregister(rt, R31IsZR);
switch (size) {
case 0: {
const uint8_t val = static_cast<uint8_t>(rt_val32);
WriteB(address, val);
break;
}
case 1: {
const uint16_t val = static_cast<uint16_t>(rt_val32);
WriteH(address, val, instr);
break;
}
case 2: {
const uint32_t val = static_cast<uint32_t>(rt_val32);
WriteW(address, val, instr);
break;
}
case 3: {
const int64_t val = get_register(rt, R31IsZR);
WriteX(address, val, instr);
break;
}
default:
UNREACHABLE();
break;
}
} else {
// Format(instr, "ldr'sz 'rt, 'memop");
// Undefined case.
if ((size == 3) && (instr->Bits(22, 2) == 3)) {
UnimplementedInstruction(instr);
return;
}
// Read the value.
const bool signd = instr->Bit(23) == 1;
// Write the W register for signed values when size < 2.
// Write the W register for unsigned values when size == 2.
const bool use_w =
(signd && (instr->Bit(22) == 1)) || (!signd && (size == 2));
int64_t val = 0; // Sign extend into an int64_t.
switch (size) {
case 0: {
if (signd) {
val = static_cast<int64_t>(ReadB(address));
} else {
val = static_cast<int64_t>(ReadBU(address));
}
break;
}
case 1: {
if (signd) {
val = static_cast<int64_t>(ReadH(address, instr));
} else {
val = static_cast<int64_t>(ReadHU(address, instr));
}
break;
}
case 2: {
if (signd) {
val = static_cast<int64_t>(ReadW(address, instr));
} else {
val = static_cast<int64_t>(ReadWU(address, instr));
}
break;
}
case 3:
val = ReadX(address, instr);
break;
default:
UNREACHABLE();
break;
}
// Write to register.
if (use_w) {
set_wregister(rt, static_cast<int32_t>(val), R31IsZR);
} else {
set_register(instr, rt, val, R31IsZR);
}
}
}
// Do writeback.
if (wb) {
set_register(instr, rn, wb_address, R31IsSP);
}
}
void Simulator::DecodeLoadStoreRegPair(Instr* instr) {
const int32_t opc = instr->Bits(23, 3);
const Register rn = instr->RnField();
const Register rt = instr->RtField();
const Register rt2 = instr->Rt2Field();
const int64_t rn_val = get_register(rn, R31IsSP);
const intptr_t shift = 2 + instr->SFField();
const intptr_t size = 1 << shift;
const int32_t offset = (instr->SImm7Field() << shift);
uword address = 0;
uword wb_address = 0;
bool wb = false;
if ((instr->Bits(30, 2) == 3) || (instr->Bit(26) != 0)) {
UnimplementedInstruction(instr);
return;
}
// Calculate address.
switch (opc) {
case 1:
address = rn_val;
wb_address = rn_val + offset;
wb = true;
break;
case 2:
address = rn_val + offset;
break;
case 3:
address = rn_val + offset;
wb_address = address;
wb = true;
break;
default:
UnimplementedInstruction(instr);
return;
}
// Check the address.
if (IsIllegalAddress(address)) {
HandleIllegalAccess(address, instr);
return;
}
// Do access.
if (instr->Bit(22)) {
// Format(instr, "ldp'sf 'rt, 'ra, 'memop");
const bool signd = instr->Bit(30) == 1;
int64_t val1 = 0; // Sign extend into an int64_t.
int64_t val2 = 0;
if (instr->Bit(31) == 1) {
// 64-bit read.
val1 = ReadX(address, instr);
val2 = ReadX(address + size, instr);
} else {
if (signd) {
val1 = static_cast<int64_t>(ReadW(address, instr));
val2 = static_cast<int64_t>(ReadW(address + size, instr));
} else {
val1 = static_cast<int64_t>(ReadWU(address, instr));
val2 = static_cast<int64_t>(ReadWU(address + size, instr));
}
}
// Write to register.
if (instr->Bit(31) == 1) {
set_register(instr, rt, val1, R31IsZR);
set_register(instr, rt2, val2, R31IsZR);
} else {
set_wregister(rt, static_cast<int32_t>(val1), R31IsZR);
set_wregister(rt2, static_cast<int32_t>(val2), R31IsZR);
}
} else {
// Format(instr, "stp'sf 'rt, 'ra, 'memop");
if (instr->Bit(31) == 1) {
const int64_t val1 = get_register(rt, R31IsZR);
const int64_t val2 = get_register(rt2, R31IsZR);
WriteX(address, val1, instr);
WriteX(address + size, val2, instr);
} else {
const int32_t val1 = get_wregister(rt, R31IsZR);
const int32_t val2 = get_wregister(rt2, R31IsZR);
WriteW(address, val1, instr);
WriteW(address + size, val2, instr);
}
}
// Do writeback.
if (wb) {
set_register(instr, rn, wb_address, R31IsSP);
}
}
void Simulator::DecodeLoadRegLiteral(Instr* instr) {
if ((instr->Bit(31) != 0) || (instr->Bit(29) != 0) ||
(instr->Bits(24, 3) != 0)) {
UnimplementedInstruction(instr);
}
const Register rt = instr->RtField();
const int64_t off = instr->SImm19Field() << 2;
const int64_t pc = reinterpret_cast<int64_t>(instr);
const int64_t address = pc + off;
const int64_t val = ReadX(address, instr);
if (instr->Bit(30)) {
// Format(instr, "ldrx 'rt, 'pcldr");
set_register(instr, rt, val, R31IsZR);
} else {
// Format(instr, "ldrw 'rt, 'pcldr");
set_wregister(rt, static_cast<int32_t>(val), R31IsZR);
}
}
void Simulator::DecodeLoadStoreExclusive(Instr* instr) {
if ((instr->Bit(23) != 0) || (instr->Bit(21) != 0) || (instr->Bit(15) != 0)) {
UNIMPLEMENTED();
}
const int32_t size = instr->Bits(30, 2);
if (size != 3 && size != 2) {
UNIMPLEMENTED();
}
const Register rs = instr->RsField();
const Register rn = instr->RnField();
const Register rt = instr->RtField();
ASSERT(instr->Rt2Field() == R31); // Should-Be-One
const bool is_load = instr->Bit(22) == 1;
if (is_load) {
ASSERT(rs == R31); // Should-Be-One
// Format(instr, "ldxr 'rt, 'rn");
if (size == 3) {
const int64_t addr = get_register(rn, R31IsSP);
intptr_t value = ReadExclusiveX(addr, instr);
set_register(instr, rt, value, R31IsSP);
} else {
const int64_t addr = get_register(rn, R31IsSP);
intptr_t value = ReadExclusiveW(addr, instr);
set_register(instr, rt, value, R31IsSP);
}
} else {
// Format(instr, "stxr 'rs, 'rt, 'rn");
if (size == 3) {
uword value = get_register(rt, R31IsSP);
uword addr = get_register(rn, R31IsSP);
intptr_t status = WriteExclusiveX(addr, value, instr);
set_register(instr, rs, status, R31IsSP);
} else {
uint32_t value = get_register(rt, R31IsSP);
uword addr = get_register(rn, R31IsSP);
intptr_t status = WriteExclusiveW(addr, value, instr);
set_register(instr, rs, status, R31IsSP);
}
}
}
void Simulator::DecodeLoadStore(Instr* instr) {
if (instr->IsLoadStoreRegOp()) {
DecodeLoadStoreReg(instr);
} else if (instr->IsLoadStoreRegPairOp()) {
DecodeLoadStoreRegPair(instr);
} else if (instr->IsLoadRegLiteralOp()) {
DecodeLoadRegLiteral(instr);
} else if (instr->IsLoadStoreExclusiveOp()) {
DecodeLoadStoreExclusive(instr);
} else {
UnimplementedInstruction(instr);
}
}
int64_t Simulator::ShiftOperand(uint8_t reg_size,
int64_t value,
Shift shift_type,
uint8_t amount) {
if (amount == 0) {
return value;
}
int64_t mask = reg_size == kXRegSizeInBits ? kXRegMask : kWRegMask;
switch (shift_type) {
case LSL:
return (value << amount) & mask;
case LSR:
return static_cast<uint64_t>(value) >> amount;
case ASR: {
// Shift used to restore the sign.
uint8_t s_shift = kXRegSizeInBits - reg_size;
// Value with its sign restored.
int64_t s_value = (value << s_shift) >> s_shift;
return (s_value >> amount) & mask;
}
case ROR: {
if (reg_size == kWRegSizeInBits) {
value &= kWRegMask;
}
return (static_cast<uint64_t>(value) >> amount) |
((static_cast<uint64_t>(value) & ((1ULL << amount) - 1ULL))
<< (reg_size - amount));
}
default:
UNIMPLEMENTED();
return 0;
}
}
int64_t Simulator::ExtendOperand(uint8_t reg_size,
int64_t value,
Extend extend_type,
uint8_t amount) {
switch (extend_type) {
case UXTB:
value &= 0xff;
break;
case UXTH:
value &= 0xffff;
break;
case UXTW:
value &= 0xffffffff;
break;
case SXTB:
value = (value << 56) >> 56;
break;
case SXTH:
value = (value << 48) >> 48;
break;
case SXTW:
value = (value << 32) >> 32;
break;
case UXTX:
case SXTX:
break;
default:
UNREACHABLE();
break;
}
int64_t mask = (reg_size == kXRegSizeInBits) ? kXRegMask : kWRegMask;
return (value << amount) & mask;
}
int64_t Simulator::DecodeShiftExtendOperand(Instr* instr) {
const Register rm = instr->RmField();
const int64_t rm_val = get_register(rm, R31IsZR);
const uint8_t size = instr->SFField() ? kXRegSizeInBits : kWRegSizeInBits;
if (instr->IsShift()) {
const Shift shift_type = instr->ShiftTypeField();
const uint8_t shift_amount = instr->Imm6Field();
return ShiftOperand(size, rm_val, shift_type, shift_amount);
} else {
ASSERT(instr->IsExtend());
const Extend extend_type = instr->ExtendTypeField();
const uint8_t shift_amount = instr->Imm3Field();
return ExtendOperand(size, rm_val, extend_type, shift_amount);
}
UNREACHABLE();
return -1;
}
void Simulator::DecodeAddSubShiftExt(Instr* instr) {
// Format(instr, "add'sf's 'rd, 'rn, 'shift_op");
// also, sub, cmp, etc.
const bool addition = (instr->Bit(30) == 0);
const Register rd = instr->RdField();
const Register rn = instr->RnField();
const int64_t rm_val = DecodeShiftExtendOperand(instr);
if (instr->SFField()) {
// 64-bit add.
const int64_t rn_val = get_register(rn, instr->RnMode());
const int64_t alu_out = rn_val + (addition ? rm_val : -rm_val);
set_register(instr, rd, alu_out, instr->RdMode());
if (instr->HasS()) {
SetNZFlagsX(alu_out);
SetCFlag(CarryFromX(alu_out, rn_val, rm_val, addition));
SetVFlag(OverflowFromX(alu_out, rn_val, rm_val, addition));
}
} else {
// 32-bit add.
const int32_t rn_val = get_wregister(rn, instr->RnMode());
int32_t rm_val32 = static_cast<int32_t>(rm_val & kWRegMask);
int32_t carry_in = 0;
if (!addition) {
carry_in = 1;
rm_val32 = ~rm_val32;
}
const int32_t alu_out = rn_val + rm_val32 + carry_in;
set_wregister(rd, alu_out, instr->RdMode());
if (instr->HasS()) {
SetNZFlagsW(alu_out);
SetCFlag(CarryFromW(rn_val, rm_val32, carry_in));
SetVFlag(OverflowFromW(rn_val, rm_val32, carry_in));
}
}
}
void Simulator::DecodeAddSubWithCarry(Instr* instr) {
// Format(instr, "adc'sf's 'rd, 'rn, 'rm");
// Format(instr, "sbc'sf's 'rd, 'rn, 'rm");
const bool addition = (instr->Bit(30) == 0);
const Register rd = instr->RdField();
const Register rn = instr->RnField();
const Register rm = instr->RmField();
const int64_t rn_val64 = get_register(rn, R31IsZR);
const int32_t rn_val32 = get_wregister(rn, R31IsZR);
const int64_t rm_val64 = get_register(rm, R31IsZR);
int32_t rm_val32 = get_wregister(rm, R31IsZR);
const int32_t carry_in = c_flag_ ? 1 : 0;
if (instr->SFField()) {
// 64-bit add.
const int64_t alu_out =
rn_val64 + (addition ? rm_val64 : ~rm_val64) + carry_in;
set_register(instr, rd, alu_out, R31IsZR);
if (instr->HasS()) {
SetNZFlagsX(alu_out);
SetCFlag(CarryFromX(alu_out, rn_val64, rm_val64, addition));
SetVFlag(OverflowFromX(alu_out, rn_val64, rm_val64, addition));
}
} else {
// 32-bit add.
if (!addition) {
rm_val32 = ~rm_val32;
}
const int32_t alu_out = rn_val32 + rm_val32 + carry_in;
set_wregister(rd, alu_out, R31IsZR);
if (instr->HasS()) {
SetNZFlagsW(alu_out);
SetCFlag(CarryFromW(rn_val32, rm_val32, carry_in));
SetVFlag(OverflowFromW(rn_val32, rm_val32, carry_in));
}
}
}
void Simulator::DecodeLogicalShift(Instr* instr) {
const int op = (instr->Bits(29, 2) << 1) | instr->Bit(21);
const Register rd = instr->RdField();
const Register rn = instr->RnField();
const int64_t rn_val = get_register(rn, instr->RnMode());
const int64_t rm_val = DecodeShiftExtendOperand(instr);
int64_t alu_out = 0;
switch (op) {
case 0:
// Format(instr, "and'sf 'rd, 'rn, 'shift_op");
alu_out = rn_val & rm_val;
break;
case 1:
// Format(instr, "bic'sf 'rd, 'rn, 'shift_op");
alu_out = rn_val & (~rm_val);
break;
case 2:
// Format(instr, "orr'sf 'rd, 'rn, 'shift_op");
alu_out = rn_val | rm_val;
break;
case 3:
// Format(instr, "orn'sf 'rd, 'rn, 'shift_op");
alu_out = rn_val | (~rm_val);
break;
case 4:
// Format(instr, "eor'sf 'rd, 'rn, 'shift_op");
alu_out = rn_val ^ rm_val;
break;
case 5:
// Format(instr, "eon'sf 'rd, 'rn, 'shift_op");
alu_out = rn_val ^ (~rm_val);
break;
case 6:
// Format(instr, "and'sfs 'rd, 'rn, 'shift_op");
alu_out = rn_val & rm_val;
break;
case 7:
// Format(instr, "bic'sfs 'rd, 'rn, 'shift_op");
alu_out = rn_val & (~rm_val);
break;
default:
UNREACHABLE();
break;
}
// Set flags if ands or bics.
if ((op == 6) || (op == 7)) {
if (instr->SFField() == 1) {
SetNZFlagsX(alu_out);
} else {
SetNZFlagsW(alu_out);
}
SetCFlag(false);
SetVFlag(false);
}
if (instr->SFField() == 1) {
set_register(instr, rd, alu_out, instr->RdMode());
} else {
set_wregister(rd, alu_out & kWRegMask, instr->RdMode());
}
}
static int64_t divide64(int64_t top, int64_t bottom, bool signd) {
// ARM64 does not trap on integer division by zero. The destination register
// is instead set to 0.
if (bottom == 0) {
return 0;
}
if (signd) {
// INT_MIN / -1 = INT_MIN.
if ((top == static_cast<int64_t>(0x8000000000000000LL)) &&
(bottom == static_cast<int64_t>(0xffffffffffffffffLL))) {
return static_cast<int64_t>(0x8000000000000000LL);
} else {
return top / bottom;
}
} else {
const uint64_t utop = static_cast<uint64_t>(top);
const uint64_t ubottom = static_cast<uint64_t>(bottom);
return static_cast<int64_t>(utop / ubottom);
}
}
static int32_t divide32(int32_t top, int32_t bottom, bool signd) {
// ARM64 does not trap on integer division by zero. The destination register
// is instead set to 0.
if (bottom == 0) {
return 0;
}