Initial SIMDBC interpreter.

runtime/vm/simulator_dbc.cc

+// Copyright (c) 2016, 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_DBC)
+
+#if !defined(USING_SIMULATOR)
+#error "DBC is a simulated architecture"
+#endif
+
+#include "vm/simulator.h"
+
+#include "vm/assembler.h"
+#include "vm/compiler.h"
+#include "vm/constants_dbc.h"
+#include "vm/cpu.h"
+#include "vm/dart_entry.h"
+#include "vm/debugger.h"
+#include "vm/disassembler.h"
+#include "vm/lockers.h"
+#include "vm/native_arguments.h"
+#include "vm/native_entry.h"
+#include "vm/object.h"
+#include "vm/object_store.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.");
+
+// 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_ = sim->sp_;
+    fp_ = sim->fp_;
+  }
+
+  ~SimulatorSetjmpBuffer() {
+    ASSERT(simulator_->last_setjmp_buffer() == this);
+    simulator_->set_last_setjmp_buffer(link_);
+  }
+
+  SimulatorSetjmpBuffer* link() const { return link_; }
+
+  uword sp() const { return reinterpret_cast<uword>(sp_); }
+  uword fp() const { return reinterpret_cast<uword>(fp_); }
+
+  jmp_buf buffer_;
+
+ private:
+  RawObject** sp_;
+  RawObject** fp_;
+  Simulator* simulator_;
+  SimulatorSetjmpBuffer* link_;
+
+  friend class Simulator;
+
+  DISALLOW_ALLOCATION();
+  DISALLOW_COPY_AND_ASSIGN(SimulatorSetjmpBuffer);
+};
+
+
+DART_FORCE_INLINE static RawObject** SavedCallerFP(RawObject** FP) {
+  return reinterpret_cast<RawObject**>(FP[kSavedCallerFpSlotFromFp]);
+}
+
+
+DART_FORCE_INLINE static RawCode* FrameCode(RawObject** FP) {
+  return static_cast<RawCode*>(FP[kPcMarkerSlotFromFp]);
+}
+
+
+DART_FORCE_INLINE static void SetFrameCode(RawObject** FP, RawCode* code) {
+  FP[kPcMarkerSlotFromFp] = code;
+}
+
+
+DART_FORCE_INLINE static RawObject** FrameArguments(RawObject** FP,
+                                                    intptr_t argc) {
+  return FP - (kDartFrameFixedSize + argc);
+}
+
+
+class SimulatorHelpers {
+ public:
+  DART_FORCE_INLINE static RawSmi* GetClassIdAsSmi(RawObject* obj) {
+    return Smi::New(obj->IsHeapObject() ? obj->GetClassId() : kSmiCid);
+  }
+
+  DART_FORCE_INLINE static intptr_t GetClassId(RawObject* obj) {
+    return obj->IsHeapObject() ? obj->GetClassId() : kSmiCid;
+  }
+
+  DART_FORCE_INLINE static void IncrementUsageCounter(RawICData* icdata) {
+    reinterpret_cast<RawFunction*>(icdata->ptr()->owner_)
+        ->ptr()
+        ->usage_counter_++;
+  }
+
+  DART_FORCE_INLINE static bool IsStrictEqualWithNumberCheck(RawObject* lhs,
+                                                             RawObject* rhs) {
+    if (lhs == rhs) {
+      return true;
+    }
+
+    if (lhs->IsHeapObject() && rhs->IsHeapObject()) {
+      const intptr_t lhs_cid = lhs->GetClassId();
+      const intptr_t rhs_cid = rhs->GetClassId();
+      if (lhs_cid == rhs_cid) {
+        switch (lhs_cid) {
+          case kDoubleCid:
+            return (bit_cast<uint64_t, double>(
+                        static_cast<RawDouble*>(lhs)->ptr()->value_) ==
+                    bit_cast<uint64_t, double>(
+                        static_cast<RawDouble*>(rhs)->ptr()->value_));
+
+          case kMintCid:
+            return (static_cast<RawMint*>(lhs)->ptr()->value_ ==
+                    static_cast<RawMint*>(rhs)->ptr()->value_);
+
+          case kBigintCid:
+            return (DLRT_BigintCompare(static_cast<RawBigint*>(lhs),
+                                       static_cast<RawBigint*>(rhs)) == 0);
+        }
+      }
+    }
+
+    return false;
+  }
+
+  template <typename T>
+  DART_FORCE_INLINE static T* Untag(T* tagged) {
+    return tagged->ptr();
+  }
+
+  DART_FORCE_INLINE static bool CheckIndex(RawSmi* index, RawSmi* length) {
+    return !index->IsHeapObject() &&
+           (reinterpret_cast<intptr_t>(index) >= 0) &&
+           (reinterpret_cast<intptr_t>(index) <
+                reinterpret_cast<intptr_t>(length));
+  }
+
+  static bool ObjectArraySetIndexed(Thread* thread,
+                                    RawObject** FP,
+                                    RawObject** result) {
+    if (thread->isolate()->type_checks()) {
+      return false;
+    }
+
+    RawObject** args = FrameArguments(FP, 3);
+    RawSmi* index = static_cast<RawSmi*>(args[1]);
+    RawArray* array = static_cast<RawArray*>(args[0]);
+    if (CheckIndex(index, array->ptr()->length_)) {
+      array->StorePointer(array->ptr()->data() + Smi::Value(index), args[2]);
+      return true;
+    }
+    return false;
+  }
+
+  static bool ObjectArrayGetIndexed(Thread* thread,
+                                    RawObject** FP,
+                                    RawObject** result) {
+    RawObject** args = FrameArguments(FP, 2);
+    RawSmi* index = static_cast<RawSmi*>(args[1]);
+    RawArray* array = static_cast<RawArray*>(args[0]);
+    if (CheckIndex(index, array->ptr()->length_)) {
+      *result = array->ptr()->data()[Smi::Value(index)];
+      return true;
+    }
+    return false;
+  }
+
+  static bool GrowableArraySetIndexed(Thread* thread,
+                                      RawObject** FP,
+                                      RawObject** result) {
+    if (thread->isolate()->type_checks()) {
+      return false;
+    }
+
+    RawObject** args = FrameArguments(FP, 3);
+    RawSmi* index = static_cast<RawSmi*>(args[1]);
+    RawGrowableObjectArray* array =
+        static_cast<RawGrowableObjectArray*>(args[0]);
+    if (CheckIndex(index, array->ptr()->length_)) {
+      RawArray* data = array->ptr()->data_;
+      data->StorePointer(data->ptr()->data() + Smi::Value(index), args[2]);
+      return true;
+    }
+    return false;
+  }
+
+  static bool GrowableArrayGetIndexed(Thread* thread,
+                                      RawObject** FP,
+                                      RawObject** result) {
+    RawObject** args = FrameArguments(FP, 2);
+    RawSmi* index = static_cast<RawSmi*>(args[1]);
+    RawGrowableObjectArray* array =
+        static_cast<RawGrowableObjectArray*>(args[0]);
+    if (CheckIndex(index, array->ptr()->length_)) {
+      *result = array->ptr()->data_->ptr()->data()[Smi::Value(index)];
+      return true;
+    }
+    return false;
+  }
+};
+
+
+DART_FORCE_INLINE static uint32_t* SavedCallerPC(RawObject** FP) {
+  return reinterpret_cast<uint32_t*>(FP[kSavedCallerPcSlotFromFp]);
+}
+
+
+DART_FORCE_INLINE static RawFunction* FrameFunction(RawObject** FP) {
+  RawFunction* function = static_cast<RawFunction*>(FP[kFunctionSlotFromFp]);
+  ASSERT(SimulatorHelpers::GetClassId(function) == kFunctionCid);
+  return function;
+}
+
+
+IntrinsicHandler Simulator::intrinsics_[Simulator::kIntrinsicCount];
+
+
+// Synchronization primitives support.
+void Simulator::InitOnce() {
+  for (intptr_t i = 0; i < kIntrinsicCount; i++) {
+    intrinsics_[i] = 0;
+  }
+
+  intrinsics_[kObjectArraySetIndexedIntrinsic] =
+      SimulatorHelpers::ObjectArraySetIndexed;
+  intrinsics_[kObjectArrayGetIndexedIntrinsic] =
+      SimulatorHelpers::ObjectArrayGetIndexed;
+  intrinsics_[kGrowableArraySetIndexedIntrinsic] =
+      SimulatorHelpers::GrowableArraySetIndexed;
+  intrinsics_[kGrowableArrayGetIndexedIntrinsic] =
+      SimulatorHelpers::GrowableArrayGetIndexed;
+}
+
+
+Simulator::Simulator()
+    : stack_(NULL),
+      fp_(NULL),
+      sp_(NULL) {
+  // 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 uintptr_t[(OSThread::GetSpecifiedStackSize() +
+                          OSThread::kStackSizeBuffer +
+                          kSimulatorStackUnderflowSize) /
+                         sizeof(uintptr_t)];
+  last_setjmp_buffer_ = NULL;
+  top_exit_frame_info_ = 0;
+}
+
+
+Simulator::~Simulator() {
+  delete[] stack_;
+  Isolate* isolate = Isolate::Current();
+  if (isolate != NULL) {
+    isolate->set_simulator(NULL);
+  }
+}
+
+
+// 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;
+}
+
+
+// Returns the top of the stack area to enable checking for stack pointer
+// validity.
+uword Simulator::StackTop() const {
+  // To be safe in potential stack underflows we leave some buffer above and
+  // set the stack top.
+  return StackBase() +
+         (OSThread::GetSpecifiedStackSize() + OSThread::kStackSizeBuffer);
+}
+
+
+// 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 int32_t (*SimulatorLeafRuntimeCall)(int32_t r0,
+                                            int32_t r1,
+                                            int32_t r2,
+                                            int32_t r3);
+
+// Calls to leaf float Dart runtime functions are based on this interface.
+typedef double (*SimulatorLeafFloatRuntimeCall)(double d0, double d1);
+
+// Calls to native Dart functions are based on this interface.
+typedef void (*SimulatorBootstrapNativeCall)(NativeArguments* arguments);
+typedef void (*SimulatorNativeCall)(NativeArguments* arguments, uword target);
+
+
+void Simulator::Exit(Thread* thread,
+                     RawObject** base,
+                     RawObject** frame,
+                     uint32_t* pc) {
+  frame[0] = Function::null();
+  frame[1] = Code::null();
+  frame[2] = reinterpret_cast<RawObject*>(pc);
+  frame[3] = reinterpret_cast<RawObject*>(base);
+  fp_ = sp_ = frame + kDartFrameFixedSize;
+  thread->set_top_exit_frame_info(reinterpret_cast<uword>(sp_));
+}
+
+
+#if defined(__has_builtin)
+#if __has_builtin(__builtin_smul_overflow)
+#define HAS_MUL_OVERFLOW
+#endif
+#if __has_builtin(__builtin_sadd_overflow)
+#define HAS_ADD_OVERFLOW
+#endif
+#if __has_builtin(__builtin_ssub_overflow)
+#define HAS_SUB_OVERFLOW
+#endif
+#endif
+
+
+DART_FORCE_INLINE static int32_t SignedAddWithOverflow(int32_t lhs,
+                                                       int32_t rhs,
+                                                       intptr_t* out) {
+  int32_t res = 1;
+#if defined(HAS_ADD_OVERFLOW)
+  res = __builtin_sadd_overflow(lhs, rhs, out);

[zra, 2016/04/18 16:50:14]

It looks like these builtins return bools:

https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html

[Vyacheslav Egorov (Google), 2016/04/18 19:19:57]

Yes, I am intentionally assigning bool to an int and relying on a standard C++
behavior:  [conv.integral] says "If the source type is bool, the value false is
converted to zero and the value true is converted to one.".

Added cast to make it explicit.

+#elif defined(__i386__)
+  asm volatile(
+      "add %2, %1\n"
+      "jo 1f;\n"
+      "xor %0, %0\n"
+      "mov %1, 0(%3)\n"
+      "1: "
+      : "+r"(res), "+r"(lhs)
+      : "r"(rhs), "r"(out)
+      : "cc");
+#elif defined(__arm__)
+  asm volatile(
+      "adds %1, %1, %2;\n"
+      "bvs 1f;\n"
+      "mov %0, $0;\n"
+      "str %1, [%3, #0]\n"
+      "1:"
+      : "+r"(res), "+r"(lhs)
+      : "r"(rhs), "r"(out)
+      : "cc", "r12");
+#else
+#error "Unsupported platform"
+#endif
+  return res;
+}
+
+
+DART_FORCE_INLINE static int32_t SignedSubWithOverflow(int32_t lhs,
+                                                       int32_t rhs,
+                                                       intptr_t* out) {
+  int32_t res = 1;
+#if defined(HAS_SUB_OVERFLOW)
+  res = __builtin_ssub_overflow(lhs, rhs, out);
+#elif defined(__i386__)
+  asm volatile(
+      "sub %2, %1\n"
+      "jo 1f;\n"
+      "xor %0, %0\n"
+      "mov %1, 0(%3)\n"
+      "1: "
+      : "+r"(res), "+r"(lhs)
+      : "r"(rhs), "r"(out)
+      : "cc");
+#elif defined(__arm__)
+  asm volatile(
+      "subs %1, %1, %2;\n"
+      "bvs 1f;\n"
+      "mov %0, $0;\n"
+      "str %1, [%3, #0]\n"
+      "1:"
+      : "+r"(res), "+r"(lhs)
+      : "r"(rhs), "r"(out)
+      : "cc", "r12");
+#else
+#error "Unsupported platform"
+#endif
+  return res;
+}
+
+
+DART_FORCE_INLINE static int32_t SignedMulWithOverflow(int32_t lhs,
+                                                       int32_t rhs,
+                                                       intptr_t* out) {
+  int32_t res = 1;
+#if defined(HAS_MUL_OVERFLOW)
+  res = __builtin_smul_overflow(lhs, rhs, out);
+#elif defined(__i386__)
+  asm volatile(
+      "imul %2, %1\n"
+      "jo 1f;\n"
+      "xor %0, %0\n"
+      "mov %1, 0(%3)\n"
+      "1: "
+      : "+r"(res), "+r"(lhs)
+      : "r"(rhs), "r"(out)
+      : "cc");
+#elif defined(__arm__)
+  asm volatile(
+      "smull %1, ip, %1, %2;\n"
+      "cmp ip, %1, ASR #31;\n"
+      "bne 1f;\n"
+      "mov %0, $0;\n"
+      "str %1, [%3, #0]\n"
+      "1:"
+      : "+r"(res), "+r"(lhs)
+      : "r"(rhs), "r"(out)
+      : "cc", "r12");
+#else
+#error "Unsupported platform"
+#endif
+  return res;
+}
+
+
+#define LIKELY(cond) __builtin_expect((cond), 1)
+
+
+DART_FORCE_INLINE static bool AreBothSmis(intptr_t a, intptr_t b) {
+  return ((a | b) & kHeapObjectTag) == 0;
+}
+
+
+#define SMI_MUL(lhs, rhs, pres) SignedMulWithOverflow((lhs), (rhs) >> 1, pres)
+#define SMI_COND(cond, lhs, rhs, pres) \
+  ((*(pres) = ((lhs cond rhs) ? true_value : false_value)), false)
+#define SMI_EQ(lhs, rhs, pres) SMI_COND(==, lhs, rhs, pres)
+#define SMI_LT(lhs, rhs, pres) SMI_COND(<, lhs, rhs, pres)
+#define SMI_GT(lhs, rhs, pres) SMI_COND(>, lhs, rhs, pres)
+#define SMI_BITOR(lhs, rhs, pres) ((*(pres) = (lhs | rhs)), false)
+#define SMI_BITAND(lhs, rhs, pres) ((*(pres) = (lhs & rhs)), false)
+
+
+void Simulator::CallRuntime(Thread* thread,
+                            RawObject** base,
+                            RawObject** exit_frame,
+                            uint32_t* pc,
+                            intptr_t argc_tag,
+                            RawObject** args,
+                            RawObject** result,
+                            uword target) {
+  Exit(thread, base, exit_frame, pc);
+  NativeArguments native_args(thread, argc_tag, args, result);
+  reinterpret_cast<RuntimeFunction>(target)(native_args);
+}
+
+
+DART_FORCE_INLINE void Simulator::Invoke(Thread* thread,
+                                         RawObject** call_base,
+                                         RawObject** call_top,
+                                         RawObjectPool** pp,
+                                         uint32_t** pc,
+                                         RawObject*** FP,
+                                         RawObject*** SP) {
+  RawObject** callee_fp = call_top + kDartFrameFixedSize;
+
+  RawFunction* function = FrameFunction(callee_fp);
+  RawCode* code = function->ptr()->code_;
+  callee_fp[kPcMarkerSlotFromFp] = code;
+  callee_fp[kSavedCallerPcSlotFromFp] = reinterpret_cast<RawObject*>(*pc);
+  callee_fp[kSavedCallerFpSlotFromFp] = reinterpret_cast<RawObject*>(*FP);
+  *pp = code->ptr()->object_pool_->ptr();
+  *pc = reinterpret_cast<uint32_t*>(code->ptr()->entry_point_);
+  *FP = callee_fp;
+  *SP = *FP - 1;
+}
+
+
+void Simulator::InlineCacheMiss(int checked_args,
+                                Thread* thread,
+                                RawICData* icdata,
+                                RawObject** args,
+                                RawObject** top,
+                                uint32_t* pc,
+                                RawObject** FP,
+                                RawObject** SP) {
+  RawObject** result = top;
+  RawObject** miss_handler_args = top + 1;
+  for (intptr_t i = 0; i < checked_args; i++) {
+    miss_handler_args[i] = args[i];
+  }
+  miss_handler_args[checked_args] = icdata;
+  RuntimeFunction handler = NULL;
+  switch (checked_args) {
+    case 1:
+      handler = DRT_InlineCacheMissHandlerOneArg;
+      break;
+    case 2:
+      handler = DRT_InlineCacheMissHandlerTwoArgs;
+      break;
+    case 3:
+      handler = DRT_InlineCacheMissHandlerThreeArgs;
+      break;
+    default:
+      UNREACHABLE();
+      break;
+  }
+
+  // Handler arguments: arguments to check and an ICData object.
+  const intptr_t miss_handler_argc = checked_args + 1;
+  RawObject** exit_frame = miss_handler_args + miss_handler_argc;
+  CallRuntime(thread,
+              FP,
+              exit_frame,
+              pc,
+              miss_handler_argc,
+              miss_handler_args,
+              result,
+              reinterpret_cast<uword>(handler));
+}
+
+
+DART_FORCE_INLINE void Simulator::InstanceCall1(Thread* thread,
+                                                RawICData* icdata,
+                                                RawObject** call_base,
+                                                RawObject** top,
+                                                RawArray** argdesc,
+                                                RawObjectPool** pp,
+                                                uint32_t** pc,
+                                                RawObject*** FP,
+                                                RawObject*** SP) {
+  ASSERT(icdata->GetClassId() == kICDataCid);
+  SimulatorHelpers::IncrementUsageCounter(icdata);
+
+  const intptr_t kCheckedArgs = 1;
+  RawObject** args = call_base;
+  RawArray* cache = icdata->ptr()->ic_data_->ptr();
+
+  RawSmi* receiver_cid = SimulatorHelpers::GetClassIdAsSmi(args[0]);
+
+  bool found = false;
+  const intptr_t length = Smi::Value(cache->length_);
+  for (intptr_t i = 0;
+       i < (length - (kCheckedArgs + 2)); i += (kCheckedArgs + 2)) {
+    if (cache->data()[i + 0] == receiver_cid) {
+      top[0] = cache->data()[i + kCheckedArgs];
+      found = true;
+      break;
+    }
+  }
+
+  if (!found) {
+    InlineCacheMiss(
+        kCheckedArgs, thread, icdata, call_base, top, *pc, *FP, *SP);
+  }
+
+  *argdesc = icdata->ptr()->args_descriptor_;
+  Invoke(thread, call_base, top, pp, pc, FP, SP);
+}
+
+
+DART_FORCE_INLINE void Simulator::InstanceCall2(Thread* thread,
+                                                RawICData* icdata,
+                                                RawObject** call_base,
+                                                RawObject** top,
+                                                RawArray** argdesc,
+                                                RawObjectPool** pp,
+                                                uint32_t** pc,
+                                                RawObject*** FP,
+                                                RawObject*** SP) {
+  ASSERT(icdata->GetClassId() == kICDataCid);
+  SimulatorHelpers::IncrementUsageCounter(icdata);
+
+  const intptr_t kCheckedArgs = 2;
+  RawObject** args = call_base;
+  RawArray* cache = icdata->ptr()->ic_data_->ptr();
+
+  RawSmi* receiver_cid = SimulatorHelpers::GetClassIdAsSmi(args[0]);
+  RawSmi* arg0_cid = SimulatorHelpers::GetClassIdAsSmi(args[1]);
+
+  bool found = false;
+  const intptr_t length = Smi::Value(cache->length_);
+  for (intptr_t i = 0;
+       i < (length - (kCheckedArgs + 2)); i += (kCheckedArgs + 2)) {
+    if ((cache->data()[i + 0] == receiver_cid) &&
+        (cache->data()[i + 1] == arg0_cid)) {
+      top[0] = cache->data()[i + kCheckedArgs];
+      found = true;
+      break;
+    }
+  }
+
+  if (!found) {
+    InlineCacheMiss(
+        kCheckedArgs, thread, icdata, call_base, top, *pc, *FP, *SP);
+  }
+
+  *argdesc = icdata->ptr()->args_descriptor_;
+  Invoke(thread, call_base, top, pp, pc, FP, SP);
+}
+
+
+DART_FORCE_INLINE void Simulator::InstanceCall3(Thread* thread,
+                                                RawICData* icdata,
+                                                RawObject** call_base,
+                                                RawObject** top,
+                                                RawArray** argdesc,
+                                                RawObjectPool** pp,
+                                                uint32_t** pc,
+                                                RawObject*** FP,
+                                                RawObject*** SP) {
+  ASSERT(icdata->GetClassId() == kICDataCid);
+  SimulatorHelpers::IncrementUsageCounter(icdata);
+
+  const intptr_t kCheckedArgs = 3;
+  RawObject** args = call_base;
+  RawArray* cache = icdata->ptr()->ic_data_->ptr();
+
+  RawSmi* receiver_cid = SimulatorHelpers::GetClassIdAsSmi(args[0]);
+  RawSmi* arg0_cid = SimulatorHelpers::GetClassIdAsSmi(args[1]);
+  RawSmi* arg1_cid = SimulatorHelpers::GetClassIdAsSmi(args[2]);
+
+  bool found = false;
+  const intptr_t length = Smi::Value(cache->length_);
+  for (intptr_t i = 0;
+       i < (length - (kCheckedArgs + 2)); i += (kCheckedArgs + 2)) {
+    if ((cache->data()[i + 0] == receiver_cid) &&
+        (cache->data()[i + 1] == arg0_cid) &&
+        (cache->data()[i + 2] == arg1_cid)) {
+      top[0] = cache->data()[i + kCheckedArgs];
+      found = true;
+      break;
+    }
+  }
+
+  if (!found) {
+    InlineCacheMiss(
+        kCheckedArgs, thread, icdata, call_base, top, *pc, *FP, *SP);
+  }
+
+  *argdesc = icdata->ptr()->args_descriptor_;
+  Invoke(thread, call_base, top, pp, pc, FP, SP);
+}
+
+
+// Note: functions below are marked DART_NOINLINE to recover performance on
+// ARM where inlining these functions into the interpreter loop seemed to cause
+// some code quality issues.
+static DART_NOINLINE bool InvokeRuntime(
+    Thread* thread,
+    Simulator* sim,
+    RuntimeFunction drt,
+    const NativeArguments& args) {
+  SimulatorSetjmpBuffer buffer(sim);
+  if (!setjmp(buffer.buffer_)) {
+    thread->set_vm_tag(reinterpret_cast<uword>(drt));
+    drt(args);
+    thread->set_vm_tag(VMTag::kDartTagId);
+    return true;
+  } else {
+    return false;
+  }
+}
+
+
+static DART_NOINLINE bool InvokeNative(
+    Thread* thread,
+    Simulator* sim,
+    SimulatorBootstrapNativeCall f,
+    NativeArguments* args) {
+  SimulatorSetjmpBuffer buffer(sim);
+  if (!setjmp(buffer.buffer_)) {
+    thread->set_vm_tag(reinterpret_cast<uword>(f));
+    f(args);
+    thread->set_vm_tag(VMTag::kDartTagId);
+    return true;
+  } else {
+    return false;
+  }
+}
+
+
+static DART_NOINLINE bool InvokeNativeWrapper(
+    Thread* thread,
+    Simulator* sim,
+    Dart_NativeFunction f,
+    NativeArguments* args) {
+  SimulatorSetjmpBuffer buffer(sim);
+  if (!setjmp(buffer.buffer_)) {
+    thread->set_vm_tag(reinterpret_cast<uword>(f));
+    NativeEntry::NativeCallWrapper(reinterpret_cast<Dart_NativeArguments>(args),
+                                   f);
+    thread->set_vm_tag(VMTag::kDartTagId);
+    return true;
+  } else {
+    return false;
+  }
+}
+
+// Note: all macro helpers are intended to be used only inside Simulator::Call.
+
+// Decode opcode and A part of the given value and dispatch to the
+// corresponding bytecode handler.
+#define DISPATCH_OP(val)         \
+  do {                           \
+    op = (val);                \
+    rA = ((op >> 8) & 0xFF);   \
+    goto* dispatch[op & 0xFF]; \
+  } while (0)
+
+// Fetch next operation from PC, increment program counter and dispatch.
+#define DISPATCH() DISPATCH_OP(*pc++)
+
+// Define entry point that handles bytecode Name with the given operand format.
+#define BYTECODE(Name, Operands) \
+  BYTECODE_HEADER(Name, DECLARE_##Operands, DECODE_##Operands)
+
+#define BYTECODE_HEADER(Name, Declare, Decode) \
+  Declare;                                     \
+  bc##Name : Decode                            \
+
+// Helpers to decode common instruction formats. Used in conjunction with
+// BYTECODE() macro.
+#define DECLARE_A_B_C uint16_t rB, rC; USE(rB); USE(rC)
+#define DECODE_A_B_C \
+  rB = ((op >> Bytecode::kBShift) & Bytecode::kBMask);    \
+  rC = ((op >> Bytecode::kCShift) & Bytecode::kCMask);
+
+#define DECLARE_0
+#define DECODE_0
+
+#define DECLARE_A
+#define DECODE_A
+
+#define DECLARE___D uint32_t rD; USE(rD)
+#define DECODE___D rD = (op >> Bytecode::kDShift);
+
+#define DECLARE_A_D DECLARE___D
+#define DECODE_A_D DECODE___D
+
+#define DECLARE_A_X int32_t rD; USE(rD)
+#define DECODE_A_X rD = (static_cast<int32_t>(op) >> Bytecode::kDShift);
+
+// Declare bytecode handler for a smi operation (e.g. AddTOS) with the
+// given result type and the given behavior specified as a function
+// that takes left and right operands and result slot and returns
+// true if fast-path succeeds.
+#define SMI_FASTPATH_TOS(ResultT, Func)                                        \
+  {                                                                            \
+    const intptr_t lhs = reinterpret_cast<intptr_t>(SP[-1]);                   \
+    const intptr_t rhs = reinterpret_cast<intptr_t>(SP[-0]);                   \
+    ResultT* slot = reinterpret_cast<ResultT*>(SP - 1);                        \
+    if (LIKELY(AreBothSmis(lhs, rhs) && !Func(lhs, rhs, slot))) {              \

[zra, 2016/04/18 16:50:14]

It looks like the functions passed for Func return an int32_t, so this should be
(Func(lhs, rhs, slot) == 0)).

[Vyacheslav Egorov (Google), 2016/04/18 19:19:56]

Not all of them. SMI_GT for example returns boolean false always. 

I fixed this - made all functions return boolean.

+      /* Fast path succeeded. Skip the generic call that follows. */           \
+      pc++;                                                                    \
+      /* We dropped 2 arguments and push result                   */           \
+      SP--;                                                                    \
+    }                                                                          \
+    DISPATCH();                                                                \

[zra, 2016/04/18 16:50:14]

I'd pull the DISPATCH() out of the macro to match the rest of the code, i.e.:

BYTECODE()
...
DISPATCH() 

[Vyacheslav Egorov (Google), 2016/04/18 19:19:56]

Done.

+  }
+
+// Exception handling helper. Gets handler FP and PC from the Simulator where
+// they were stored by Simulator::Longjmp and proceeds to execute the handler.
+// Corner case: handler PC can be a fake marker that marks entry frame, which
+// means exception was not handled in the Dart code. In this case we return
+// caught exception from Simulator::Call.
+#define HANDLE_EXCEPTION                                                       \
+  do {                                                                         \
+    FP = reinterpret_cast<RawObject**>(fp_);                                   \
+    pc = reinterpret_cast<uint32_t*>(pc_);                                     \
+    if ((reinterpret_cast<uword>(pc) & 2) != 0) {  /* Entry frame? */          \
+      fp_ = sp_ = reinterpret_cast<RawObject**>(fp_[0]);                       \
+      thread->set_top_exit_frame_info(reinterpret_cast<uword>(sp_));           \
+      thread->set_top_resource(top_resource);                                  \
+      thread->set_vm_tag(vm_tag);                                              \
+      return special_[kExceptionSpecialIndex];                                 \
+    }                                                                          \
+    pp = FrameCode(FP)->ptr()->object_pool_->ptr();                            \
+    goto DispatchAfterException;                                               \
+  } while (0)                                                                  \
+
+// Runtime call helpers: handle invocation and potential exception after return.
+#define INVOKE_RUNTIME(Func, Args)                \
+  if (!InvokeRuntime(thread, this, Func, Args)) { \
+    HANDLE_EXCEPTION;                             \
+  }                                               \
+
+#define INVOKE_NATIVE(Func, Args)                 \
+  if (!InvokeNative(thread, this, Func, &Args)) { \
+    HANDLE_EXCEPTION;                             \
+  }                                               \
+
+#define INVOKE_NATIVE_WRAPPER(Func, Args)                \
+  if (!InvokeNativeWrapper(thread, this, Func, &Args)) { \
+    HANDLE_EXCEPTION;                                    \
+  }                                                      \
+
+#define LOAD_CONSTANT(index) (pp->data()[(index)].raw_obj_)
+
+RawObject* Simulator::Call(const Code& code,
+                           const Array& arguments_descriptor,
+                           const Array& arguments,
+                           Thread* thread) {
+  // Dispatch used to interpret bytecode. Contains addresses of
+  // labels of bytecode handlers. Handlers themselves are defined below.
+  static const void* dispatch[] = {
+#define TARGET(name, fmt, fmta, fmtb, fmtc) &&bc##name,
+      BYTECODES_LIST(TARGET)
+#undef TARGET
+  };
+
+  // Interpreter state (see constants_dbc.h for high-level overview).
+  uint32_t* pc;  // Program Counter: points to the next op to execute.
+  RawObjectPool* pp;  // Pool Pointer.
+  RawObject** FP;  // Frame Pointer.
+  RawObject** SP;  // Stack Pointer.
+
+  RawArray* argdesc;  // Arguments Descriptor: used to pass information between
+                      // call instruction and the function entry.
+
+  uint32_t op;  // Currently executing op.
+  uint16_t rA;  // A component of the currently executing op.
+
+  if (sp_ == NULL) {
+    fp_ = sp_ = reinterpret_cast<RawObject**>(stack_);
+  }
+
+  // Save current VM tag and mark thread as executing Dart code.
+  const uword vm_tag = thread->vm_tag();
+  thread->set_vm_tag(VMTag::kDartTagId);
+
+  // Save current top stack resource and reset the list.
+  StackResource* top_resource = thread->top_resource();
+  thread->set_top_resource(NULL);
+
+  // Setup entry frame:
+  //
+  //                        ^
+  //                        |  previous Dart frames
+  //       ~~~~~~~~~~~~~~~  |
+  //       | ........... | -+
+  // fp_ > |             |     saved top_exit_frame_info
+  //       | arg 0       | -+
+  //       ~~~~~~~~~~~~~~~  |
+  //                         > incoming arguments
+  //       ~~~~~~~~~~~~~~~  |
+  //       | arg 1       | -+
+  //       | function    | -+
+  //       | code        |  |
+  //       | callee PC   | ---> special fake PC marking an entry frame
+  //  SP > | fp_         |  |
+  //  FP > | ........... |   > normal Dart frame (see stack_frame_dbc.h)
+  //                        |
+  //                        v
+  //
+  FP = fp_ + 1 + arguments.Length() + kDartFrameFixedSize;
+  SP = FP - 1;
+
+  // Save outer top_exit_frame_info.
+  fp_[0] = reinterpret_cast<RawObject*>(thread->top_exit_frame_info());
+
+  // Copy arguments and setup the Dart frame.
+  const intptr_t argc = arguments.Length();
+  for (intptr_t i = 0; i < argc; i++) {
+    fp_[1 + i] = arguments.At(i);
+  }
+
+  FP[kFunctionSlotFromFp] = code.function();
+  FP[kPcMarkerSlotFromFp] = code.raw();
+  FP[kSavedCallerPcSlotFromFp] = reinterpret_cast<RawObject*>((argc << 2) | 2);
+  FP[kSavedCallerFpSlotFromFp] = reinterpret_cast<RawObject*>(fp_);
+
+  // Load argument descriptor.
+  argdesc = arguments_descriptor.raw();
+
+  // Ready to start executing bytecode. Load entry point and corresponding
+  // object pool.
+  pc = reinterpret_cast<uint32_t*>(code.raw()->ptr()->entry_point_);
+  pp = code.object_pool()->ptr();
+
+  // Cache some frequently used values in the frame.
+  RawBool* true_value = Bool::True().raw();
+  RawBool* false_value = Bool::False().raw();
+  RawObject* null_value = Object::null();
+  RawObject* empty_context = thread->isolate()->object_store()->empty_context();
+
+#if defined(DEBUG)
+  Function& function_h = Function::Handle();
+#endif
+
+  // Enter the dispatch loop.
+  DISPATCH();
+
+  // Bytecode handlers (see constants_dbc.h for bytecode descriptions).
+  {
+    BYTECODE(Entry, A_B_C);
+    const uint8_t num_fixed_params = rA;
+    const uint16_t num_locals = rB;
+    const uint16_t context_reg = rC;
+
+    // Decode arguments descriptor.
+    const intptr_t pos_count = Smi::Value(*reinterpret_cast<RawSmi**>(
+        reinterpret_cast<uword>(argdesc->ptr()) +
+        Array::element_offset(ArgumentsDescriptor::kPositionalCountIndex)));
+
+    // Check that we got the right number of positional parameters.
+    if (pos_count != num_fixed_params) {
+      // Mismatch can only occur if current function is a closure.
+      goto ClosureNoSuchMethod;
+    }
+
+    // Initialize locals with null and set current context variable to
+    // empty context.
+    {
+      RawObject** L = FP;
+      for (intptr_t i = 0; i < num_locals; i++) {
+        L[i] = null_value;
+      }
+      L[context_reg] = empty_context;
+      SP = FP + num_locals - 1;
+    }
+
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(EntryOpt, A_B_C);
+    const uint16_t num_fixed_params = rA;
+    const uint16_t num_opt_pos_params = rB;
+    const uint16_t num_opt_named_params = rC;
+    const intptr_t min_num_pos_args = num_fixed_params;
+    const intptr_t max_num_pos_args = num_fixed_params + num_opt_pos_params;
+
+    // Decode arguments descriptor.
+    const intptr_t arg_count = Smi::Value(*reinterpret_cast<RawSmi**>(
+        reinterpret_cast<uword>(argdesc->ptr()) +
+        Array::element_offset(ArgumentsDescriptor::kCountIndex)));
+    const intptr_t pos_count = Smi::Value(*reinterpret_cast<RawSmi**>(
+        reinterpret_cast<uword>(argdesc->ptr()) +
+        Array::element_offset(ArgumentsDescriptor::kPositionalCountIndex)));
+    const intptr_t named_count = (arg_count - pos_count);
+
+    // Check that got the right number of positional parameters.
+    if (!(min_num_pos_args <= pos_count && pos_count <= max_num_pos_args)) {

[zra, 2016/04/18 16:50:14]

parens around comparisons.

[Vyacheslav Egorov (Google), 2016/04/18 19:19:57]

Done.

+      goto ClosureNoSuchMethod;
+    }
+
+    // Copy all passed position arguments.
+    RawObject** first_arg = FrameArguments(FP, arg_count);
+    memmove(FP, first_arg, pos_count * kWordSize);
+
+    if (num_opt_named_params != 0) {
+      // This is a function with named parameters.
+      // Walk the list of named parameters and their
+      // default values encoded as pairs of LoadConstant instructions that
+      // follows the entry point and find matching values via arguments
+      // descriptor.
+      RawObject** argdesc_data = argdesc->ptr()->data();
+
+      intptr_t i = named_count - 1;  // argument position
+      intptr_t j = num_opt_named_params - 1;  // parameter position
+      while (j >= 0 && i >= 0) {

[zra, 2016/04/18 16:50:14]

ditto

[Vyacheslav Egorov (Google), 2016/04/18 19:19:56]

Done.

+        // Fetch formal parameter information: name, default value, target slot.
+        const uint32_t load_name = pc[2 * j];
+        const uint32_t load_value = pc[2 * j + 1];
+        ASSERT(Bytecode::DecodeOpcode(load_name) == Bytecode::kLoadConstant);
+        ASSERT(Bytecode::DecodeOpcode(load_value) == Bytecode::kLoadConstant);
+        const uint8_t reg = Bytecode::DecodeA(load_name);
+        ASSERT(reg == Bytecode::DecodeA(load_value));
+
+        RawString* name = static_cast<RawString*>(
+            LOAD_CONSTANT(Bytecode::DecodeD(load_name)));
+        if (name == argdesc_data[ArgumentsDescriptor::name_index(i)]) {
+          // Parameter was passed. Fetch passed value.
+          const intptr_t arg_index = Smi::Value(static_cast<RawSmi*>(
+              argdesc_data[ArgumentsDescriptor::position_index(i)]));
+          FP[reg] = first_arg[arg_index];
+          i--;  // Consume passed argument.
+        } else {
+          // Parameter was not passed. Fetch default value.
+          FP[reg] = LOAD_CONSTANT(Bytecode::DecodeD(load_value));
+        }
+        j--;  // Next formal parameter.
+      }
+
+      // If we have unprocessed formal parameters then initialize them all
+      // using default values.
+      while (j >= 0) {
+        const uint32_t load_name = pc[2 * j];
+        const uint32_t load_value = pc[2 * j + 1];
+        ASSERT(Bytecode::DecodeOpcode(load_name) == Bytecode::kLoadConstant);
+        ASSERT(Bytecode::DecodeOpcode(load_value) == Bytecode::kLoadConstant);
+        const uint8_t reg = Bytecode::DecodeA(load_name);
+        ASSERT(reg == Bytecode::DecodeA(load_value));
+
+        FP[reg] = LOAD_CONSTANT(Bytecode::DecodeD(load_value));
+        j--;
+      }
+
+      // If we have unprocessed passed arguments that means we have mismatch
+      // between formal parameters and concrete arguments. This can only
+      // occur if the current function is a closure.
+      if (i != -1) {
+        goto ClosureNoSuchMethod;
+      }
+
+      // Skip LoadConstant-s encoding information about named parameters.
+      pc += num_opt_named_params * 2;
+
+      // SP points past copied arguments.
+      SP = FP + num_fixed_params + num_opt_named_params - 1;
+    } else {
+      ASSERT(num_opt_pos_params != 0);
+      if (named_count != 0) {
+        // Function can't have both named and optional positional parameters.
+        // This kind of mismatch can only occur if the current function
+        // is a closure.
+        goto ClosureNoSuchMethod;
+      }
+
+      // Process the list of default values encoded as a sequence of
+      // LoadConstant instructions after EntryOpt bytecode.
+      // Execute only those that correspond to parameters the were not passed.
+      for (intptr_t i = pos_count - num_fixed_params;
+           i < num_opt_pos_params;
+           i++) {
+        const uint32_t load_value = pc[i];
+        ASSERT(Bytecode::DecodeOpcode(load_value) == Bytecode::kLoadConstant);
+#if defined(DEBUG)
+        const uint8_t reg = Bytecode::DecodeA(load_value);
+        ASSERT((num_fixed_params + i) == reg);
+#endif
+        FP[num_fixed_params + i] = LOAD_CONSTANT(Bytecode::DecodeD(load_value));
+      }
+
+      // Skip LoadConstant-s encoding default values for optional positional
+      // parameters.
+      pc += num_opt_pos_params;
+
+      // SP points past the last copied parameter.
+      SP = FP + max_num_pos_args - 1;
+    }
+
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(Frame, A_D);
+    // Initialize locals with null and increment SP.
+    const uint16_t num_locals = rD;
+    for (intptr_t i = 1; i <= num_locals; i++) {
+      SP[i] = null_value;
+    }
+    SP += num_locals;
+
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(SetFrame, A);
+    SP = FP + rA - 1;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(Compile, 0);
+    FP[0] = FrameFunction(FP);
+    FP[1] = 0;
+    Exit(thread, FP, FP + 2, pc);
+    NativeArguments args(thread, 1, FP, FP + 1);
+    INVOKE_RUNTIME(DRT_CompileFunction, args);
+    {
+      // Function should be compiled now, dispatch to its entry point.
+      RawCode* code = FrameFunction(FP)->ptr()->code_;
+      SetFrameCode(FP, code);
+      pp = code->ptr()->object_pool_->ptr();
+      pc = reinterpret_cast<uint32_t*>(code->ptr()->entry_point_);
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(CheckStack, A);
+    {
+      if (reinterpret_cast<uword>(SP) >= thread->isolate()->stack_limit()) {
+        Exit(thread, FP, SP + 1, pc);
+        NativeArguments args(thread, 0, NULL, NULL);
+        INVOKE_RUNTIME(DRT_StackOverflow, args);
+      }
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(DebugStep, A);
+    if (thread->isolate()->single_step()) {
+      Exit(thread, FP, SP + 1, pc);
+      NativeArguments args(thread, 0, NULL, NULL);
+      INVOKE_RUNTIME(DRT_SingleStepHandler, args);
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(DebugBreak, A);
+    {
+      const uint32_t original_bc =
+          static_cast<uint32_t>(reinterpret_cast<uintptr_t>(
+              thread->isolate()->debugger()->GetPatchedStubAddress(
+                  reinterpret_cast<uword>(pc))));
+
+      SP[1] = null_value;
+      Exit(thread, FP, SP + 2, pc);
+      NativeArguments args(thread, 0, NULL, SP + 1);
+      INVOKE_RUNTIME(DRT_BreakpointRuntimeHandler, args)
+      DISPATCH_OP(original_bc);
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(InstantiateType, A_D);
+    RawObject* type = LOAD_CONSTANT(rD);
+    SP[1] = type;
+    SP[2] = SP[0];
+    SP[0] = null_value;
+    Exit(thread, FP, SP + 3, pc);
+    {
+      NativeArguments args(thread, 2, SP + 1, SP);
+      INVOKE_RUNTIME(DRT_InstantiateType, args);
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(InstantiateTypeArgumentsTOS, A_D);
+    RawTypeArguments* type_arguments =
+        static_cast<RawTypeArguments*>(LOAD_CONSTANT(rD));
+
+    RawObject* instantiator = SP[0];
+    // If the instantiator is null and if the type argument vector
+    // instantiated from null becomes a vector of dynamic, then use null as
+    // the type arguments.
+    if (rA == 0 || null_value != instantiator) {
+      // First lookup in the cache.
+      RawArray* instantiations = type_arguments->ptr()->instantiations_;
+      for (intptr_t i = 0;
+           instantiations->ptr()->data()[i] != NULL;  // kNoInstantiator
+           i += 2) {
+        if (instantiations->ptr()->data()[i] == instantiator) {
+          // Found in the cache.
+          SP[0] = instantiations->ptr()->data()[i + 1];
+          goto InstantiateTypeArgumentsTOSDone;
+        }
+      }
+
+      // Cache lookup failed, call runtime.
+      SP[1] = type_arguments;
+      SP[2] = instantiator;
+
+      Exit(thread, FP, SP + 3, pc);
+      NativeArguments args(thread, 2, SP + 1, SP);
+      INVOKE_RUNTIME(DRT_InstantiateTypeArguments, args);
+    }
+
+  InstantiateTypeArgumentsTOSDone:
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(Throw, A);
+    {
+      SP[1] = 0;  // Space for result.
+      Exit(thread, FP, SP + 2, pc);
+      if (rA == 0) {  // Throw
+        NativeArguments args(thread, 1, SP, SP + 1);
+        INVOKE_RUNTIME(DRT_Throw, args);
+      } else {  // ReThrow
+        NativeArguments args(thread, 2, SP - 1, SP + 1);
+        INVOKE_RUNTIME(DRT_ReThrow, args);
+      }
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(Drop1, 0);
+    SP--;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(Drop, 0);
+    SP -= rA;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(DropR, 0);
+    RawObject* result = SP[0];
+    SP -= rA;
+    SP[0] = result;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(LoadConstant, A_D);
+    FP[rA] = LOAD_CONSTANT(rD);
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(PushConstant, __D);
+    *++SP = LOAD_CONSTANT(rD);
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(Push, A_X);
+    *++SP = FP[rD];
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(Move, A_X);
+    FP[rA] = FP[rD];
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(StoreLocal, A_X);
+    FP[rD] = *SP;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(PopLocal, A_X);
+    FP[rD] = *SP--;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(MoveSpecial, A_D);
+    FP[rA] = special_[rD];
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(BooleanNegateTOS, 0);
+    SP[0] = (SP[0] == true_value) ? false_value : true_value;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(StaticCall, A_D);
+
+    // Check if single stepping.
+    if (thread->isolate()->single_step()) {
+      Exit(thread, FP, SP + 1, pc);
+      NativeArguments args(thread, 0, NULL, NULL);
+      INVOKE_RUNTIME(DRT_SingleStepHandler, args);
+    }
+
+    // Invoke target function.
+    {
+      const uint16_t argc = rA;
+      RawObject** call_base = SP - argc;
+      RawObject** call_top = SP;  // *SP contains function
+      argdesc = static_cast<RawArray*>(LOAD_CONSTANT(rD));
+      Invoke(thread, call_base, call_top, &pp, &pc, &FP, &SP);
+    }
+
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(InstanceCall, A_D);
+
+    // Check if single stepping.
+    if (thread->isolate()->single_step()) {
+      Exit(thread, FP, SP + 1, pc);
+      NativeArguments args(thread, 0, NULL, NULL);
+      INVOKE_RUNTIME(DRT_SingleStepHandler, args);
+    }
+
+    {
+      const uint16_t argc = rA;
+      const uint16_t kidx = rD;
+
+      RawObject** call_base = SP - argc + 1;
+      RawObject** call_top = SP + 1;
+      InstanceCall1(thread,
+                    static_cast<RawICData*>(LOAD_CONSTANT(kidx)),
+                    call_base, call_top, &argdesc, &pp, &pc, &FP, &SP);
+    }
+
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(InstanceCall2, A_D);
+    if (thread->isolate()->single_step()) {
+      Exit(thread, FP, SP + 1, pc);
+      NativeArguments args(thread, 0, NULL, NULL);
+      INVOKE_RUNTIME(DRT_SingleStepHandler, args);
+    }
+
+    {
+      const uint16_t argc = rA;
+      const uint16_t kidx = rD;
+
+      RawObject** call_base = SP - argc + 1;
+      RawObject** call_top = SP + 1;
+      InstanceCall2(thread,
+                    static_cast<RawICData*>(LOAD_CONSTANT(kidx)),
+                    call_base, call_top, &argdesc, &pp, &pc, &FP, &SP);
+    }
+
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(InstanceCall3, A_D);
+    if (thread->isolate()->single_step()) {
+      Exit(thread, FP, SP + 1, pc);
+      NativeArguments args(thread, 0, NULL, NULL);
+      INVOKE_RUNTIME(DRT_SingleStepHandler, args);
+    }
+
+    {
+      const uint16_t argc = rA;
+      const uint16_t kidx = rD;
+
+      RawObject** call_base = SP - argc + 1;
+      RawObject** call_top = SP + 1;
+      InstanceCall3(thread,
+                    static_cast<RawICData*>(LOAD_CONSTANT(kidx)),
+                    call_base, call_top, &argdesc, &pp, &pc, &FP, &SP);
+    }
+
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(NativeBootstrapCall, 0);
+    RawFunction* function = FrameFunction(FP);
+    RawObject** incoming_args =
+        function->ptr()->num_optional_parameters_ == 0

[zra, 2016/04/18 16:50:14]

parens

[Vyacheslav Egorov (Google), 2016/04/18 19:19:56]

Done.

+            ? FrameArguments(FP, function->ptr()->num_fixed_parameters_)
+            : FP;
+
+    SimulatorBootstrapNativeCall native_target =
+        reinterpret_cast<SimulatorBootstrapNativeCall>(SP[-1]);
+    intptr_t argc_tag = reinterpret_cast<intptr_t>(SP[-0]);
+    SP[-0] = 0;  // Note: argc_tag is not smi-tagged.
+    SP[-1] = null_value;
+    Exit(thread, FP, SP + 1, pc);
+    NativeArguments args(thread, argc_tag, incoming_args, SP - 1);
+    INVOKE_NATIVE(native_target, args);
+    SP -= 1;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(NativeCall, 0);
+    RawFunction* function = FrameFunction(FP);
+    RawObject** incoming_args =
+        function->ptr()->num_optional_parameters_ == 0

[zra, 2016/04/18 16:50:14]

ditto

[Vyacheslav Egorov (Google), 2016/04/18 19:19:56]

Done.

+            ? FrameArguments(FP, function->ptr()->num_fixed_parameters_)
+            : FP;
+
+    Dart_NativeFunction native_target =
+        reinterpret_cast<Dart_NativeFunction>(SP[-1]);
+    intptr_t argc_tag = reinterpret_cast<intptr_t>(SP[-0]);
+    SP[-0] = 0;  // argc_tag is not smi tagged!
+    SP[-1] = null_value;
+    Exit(thread, FP, SP + 1, pc);
+    NativeArguments args(thread, argc_tag, incoming_args, SP - 1);
+    INVOKE_NATIVE_WRAPPER(native_target, args);
+    SP -= 1;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(AddTOS, A_B_C);
+    SMI_FASTPATH_TOS(intptr_t, SignedAddWithOverflow);
+  }
+  {
+    BYTECODE(SubTOS, A_B_C);
+    SMI_FASTPATH_TOS(intptr_t, SignedSubWithOverflow);
+  }
+  {
+    BYTECODE(MulTOS, A_B_C);
+    SMI_FASTPATH_TOS(intptr_t, SMI_MUL);
+  }
+  {
+    BYTECODE(BitOrTOS, A_B_C);
+    SMI_FASTPATH_TOS(intptr_t, SMI_BITOR);
+  }
+  {
+    BYTECODE(BitAndTOS, A_B_C);
+    SMI_FASTPATH_TOS(intptr_t, SMI_BITAND);
+  }
+  {
+    BYTECODE(EqualTOS, A_B_C);
+    SMI_FASTPATH_TOS(RawObject*, SMI_EQ);
+  }
+  {
+    BYTECODE(LessThanTOS, A_B_C);
+    SMI_FASTPATH_TOS(RawObject*, SMI_LT);
+  }
+  {
+    BYTECODE(GreaterThanTOS, A_B_C);
+    SMI_FASTPATH_TOS(RawObject*, SMI_GT);
+  }
+
+  // Return and return like instructions (Instrinsic).
+  {
+    RawObject* result;  // result to return to the caller.
+
+    BYTECODE(Intrinsic, A);
+    // Try invoking intrinsic handler. If it succeeds (returns true)
+    // then just return the value it returned to the caller.
+    result = null_value;
+    if (!intrinsics_[rA](thread, FP, &result)) {
+      DISPATCH();
+    }
+    goto ReturnImpl;
+
+    BYTECODE(Return, A);
+    result = FP[rA];
+    goto ReturnImpl;
+
+    BYTECODE(ReturnTOS, 0);
+    result = *SP;
+    // Fall through to the ReturnImpl.
+
+  ReturnImpl:
+    // Restore caller PC.
+    pc = SavedCallerPC(FP);
+
+    // Check if it is a fake PC marking the entry frame.
+    if ((reinterpret_cast<uword>(pc) & 2) != 0) {
+      const intptr_t argc = reinterpret_cast<uword>(pc) >> 2;
+      fp_ = sp_ =
+          reinterpret_cast<RawObject**>(FrameArguments(FP, argc + 1)[0]);
+      thread->set_top_exit_frame_info(reinterpret_cast<uword>(sp_));
+      thread->set_top_resource(top_resource);
+      thread->set_vm_tag(vm_tag);
+      return result;
+    }
+
+    // Look at the caller to determine how many arguments to pop.
+    const uint8_t argc = Bytecode::DecodeArgc(pc[-1]);
+
+    // Restore SP, FP and PP. Push result and dispatch.
+    SP = FrameArguments(FP, argc);
+    FP = SavedCallerFP(FP);
+    pp = FrameCode(FP)->ptr()->object_pool_->ptr();
+    *SP = result;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(StoreStaticTOS, A_D);
+    RawField* field = reinterpret_cast<RawField*>(LOAD_CONSTANT(rD));
+    RawInstance* value = static_cast<RawInstance*>(*SP--);
+    field->StorePointer(&field->ptr()->value_.static_value_, value);
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(PushStatic, A_D);
+    RawField* field = reinterpret_cast<RawField*>(LOAD_CONSTANT(rD));
+    // Note: field is also on the stack, hence no increment.
+    *SP = field->ptr()->value_.static_value_;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(StoreField, A_B_C);
+    const uint16_t offset_in_words = rB;
+    const uint16_t value_reg = rC;
+
+    RawInstance* instance = reinterpret_cast<RawInstance*>(FP[rA]);
+    RawObject* value = reinterpret_cast<RawObject*>(FP[value_reg]);
+
+    instance->StorePointer(
+        reinterpret_cast<RawObject**>(instance->ptr()) + offset_in_words,
+        value);
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(StoreFieldTOS, A_D);
+    const uint16_t offset_in_words = rD;
+    RawInstance* instance = reinterpret_cast<RawInstance*>(SP[-1]);
+    RawObject* value = reinterpret_cast<RawObject*>(SP[0]);
+    SP -= 2;  // Drop instance and value.
+    instance->StorePointer(
+        reinterpret_cast<RawObject**>(instance->ptr()) + offset_in_words,
+        value);
+
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(LoadField, A_B_C);
+    const uint16_t instance_reg = rB;
+    const uint16_t offset_in_words = rC;
+    RawInstance* instance = reinterpret_cast<RawInstance*>(FP[instance_reg]);
+    FP[rA] = reinterpret_cast<RawObject**>(instance->ptr())[offset_in_words];
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(LoadFieldTOS, A_D);
+    const uint16_t offset_in_words = rD;
+    RawInstance* instance = static_cast<RawInstance*>(SP[0]);
+    SP[0] = reinterpret_cast<RawObject**>(instance->ptr())[offset_in_words];
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(InitStaticTOS, A);
+    RawField* field = static_cast<RawField*>(*SP--);
+    RawObject* value = field->ptr()->value_.static_value_;
+    if ((value == Object::sentinel().raw()) ||
+        (value == Object::transition_sentinel().raw())) {
+      // Note: SP[1] already contains the field object.
+      SP[2] = 0;
+      Exit(thread, FP, SP + 3, pc);
+      NativeArguments args(thread, 1, SP + 1, SP + 2);
+      INVOKE_RUNTIME(DRT_InitStaticField, args);
+    }
+    DISPATCH();
+  }
+
+  // TODO(vegorov) allocation bytecodes can benefit from the new-space
+  // allocation fast-path that does not transition into the runtime system.
+  {
+    BYTECODE(AllocateContext, A_D);
+    const uint16_t num_context_variables = rD;
+    {
+      *++SP = 0;
+      SP[1] = Smi::New(num_context_variables);
+      Exit(thread, FP, SP + 2, pc);
+      NativeArguments args(thread, 1, SP + 1, SP);
+      INVOKE_RUNTIME(DRT_AllocateContext, args);
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(CloneContext, A);
+    {
+      SP[1] = SP[0];  // Context to clone.
+      Exit(thread, FP, SP + 2, pc);
+      NativeArguments args(thread, 1, SP + 1, SP);
+      INVOKE_RUNTIME(DRT_CloneContext, args);
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(Allocate, A_D);
+    SP[1] = 0;  // Space for the result.
+    SP[2] = LOAD_CONSTANT(rD);  // Class object.
+    SP[3] = null_value;  // Type arguments.
+    Exit(thread, FP, SP + 4, pc);
+    NativeArguments args(thread, 2, SP + 2, SP + 1);
+    INVOKE_RUNTIME(DRT_AllocateObject, args);
+    SP++;  // Result is in SP[1].
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(AllocateT, 0);
+    SP[1] = SP[-0];  // Class object.
+    SP[2] = SP[-1];  // Type arguments
+    Exit(thread, FP, SP + 3, pc);
+    NativeArguments args(thread, 2, SP + 1, SP - 1);
+    INVOKE_RUNTIME(DRT_AllocateObject, args);
+    SP -= 1;  // Result is in SP - 1.
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(CreateArrayTOS, 0);
+    SP[1] = SP[-0];  // Length.
+    SP[2] = SP[-1];  // Type.
+    Exit(thread, FP, SP + 3, pc);
+    NativeArguments args(thread, 2, SP + 1, SP - 1);
+    INVOKE_RUNTIME(DRT_AllocateArray, args);
+    SP -= 1;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(AssertAssignable, A_D);  // Stack: instance, type args, type, name
+    RawObject** args = SP - 3;
+    if (args[0] != null_value) {
+      RawSubtypeTestCache* cache =
+          static_cast<RawSubtypeTestCache*>(LOAD_CONSTANT(rD));
+      if (cache != null_value) {
+        RawInstance* instance = static_cast<RawInstance*>(args[0]);
+        RawTypeArguments* instantiator_type_arguments =
+            static_cast<RawTypeArguments*>(args[1]);
+
+        const intptr_t cid = SimulatorHelpers::GetClassId(instance);
+
+        RawTypeArguments* instance_type_arguments =
+            static_cast<RawTypeArguments*>(null_value);
+        RawObject* instance_cid_or_function;
+        if (cid == kClosureCid) {
+          RawClosure* closure = static_cast<RawClosure*>(instance);
+          instance_type_arguments = closure->ptr()->type_arguments_;
+          instance_cid_or_function = closure->ptr()->function_;
+        } else {
+          instance_cid_or_function = Smi::New(cid);
+
+          RawClass* instance_class =
+              thread->isolate()->class_table()->At(cid);
+          if (instance_class->ptr()->num_type_arguments_ < 0) {
+            goto AssertAssignableCallRuntime;
+          } else if (instance_class->ptr()->num_type_arguments_ > 0) {
+            instance_type_arguments = reinterpret_cast<RawTypeArguments**>(
+                instance
+                    ->ptr())[instance_class->ptr()
+                                 ->type_arguments_field_offset_in_words_];
+          }
+        }
+
+        for (RawObject** entries = cache->ptr()->cache_->ptr()->data();
+             entries[0] != null_value;
+             entries += SubtypeTestCache::kTestEntryLength) {
+          if (entries[SubtypeTestCache::kInstanceClassIdOrFunction] ==

[zra, 2016/04/18 16:50:14]

parens around comparisons

[Vyacheslav Egorov (Google), 2016/04/18 19:19:57]

Done.

+                  instance_cid_or_function &&
+              entries[SubtypeTestCache::kInstanceTypeArguments] ==
+                  instance_type_arguments &&
+              entries[SubtypeTestCache::kInstantiatorTypeArguments] ==
+                  instantiator_type_arguments) {
+            if (true_value == entries[SubtypeTestCache::kTestResult]) {
+              goto AssertAssignableOk;
+            } else {
+              break;
+            }
+          }
+        }
+      }
+
+    AssertAssignableCallRuntime:
+      SP[1] = args[0];  // instance
+      SP[2] = args[2];  // type
+      SP[3] = args[1];  // type args
+      SP[4] = args[3];  // name
+      SP[5] = cache;
+      Exit(thread, FP, SP + 6, pc);
+      NativeArguments args(thread, 5, SP + 1, SP - 3);
+      INVOKE_RUNTIME(DRT_TypeCheck, args);
+    }
+
+  AssertAssignableOk:
+    SP -= 3;
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(AssertBoolean, A);
+    RawObject* value = SP[0];
+    if (rA) {  // Should we perform type check?
+      if (value == true_value || value == false_value) {

[zra, 2016/04/18 16:50:14]

ditto

[Vyacheslav Egorov (Google), 2016/04/18 19:19:57]

Done.

+        goto AssertBooleanOk;
+      }
+    } else if (value != null_value) {
+      goto AssertBooleanOk;
+    }
+
+    // Assertion failed.
+    {
+      SP[1] = SP[0];  // instance
+      Exit(thread, FP, SP + 2, pc);
+      NativeArguments args(thread, 1, SP + 1, SP);
+      INVOKE_RUNTIME(DRT_NonBoolTypeError, args);
+    }
+
+  AssertBooleanOk:
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(IfEqStrictTOS, A_D);
+    SP -= 2;
+    if (SP[1] != SP[2]) {
+      pc++;
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(IfNeStrictTOS, A_D);
+    SP -= 2;
+    if (SP[1] == SP[2]) {
+      pc++;
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(IfEqStrictNumTOS, A_D);
+    if (thread->isolate()->single_step()) {
+      Exit(thread, FP, SP + 1, pc);
+      NativeArguments args(thread, 0, NULL, NULL);
+      INVOKE_RUNTIME(DRT_SingleStepHandler, args);
+    }
+
+    SP -= 2;
+    if (!SimulatorHelpers::IsStrictEqualWithNumberCheck(SP[1], SP[2])) {
+      pc++;
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(IfNeStrictNumTOS, A_D);
+    if (thread->isolate()->single_step()) {
+      Exit(thread, FP, SP + 1, pc);
+      NativeArguments args(thread, 0, NULL, NULL);
+      INVOKE_RUNTIME(DRT_SingleStepHandler, args);
+    }
+
+    SP -= 2;
+    if (SimulatorHelpers::IsStrictEqualWithNumberCheck(SP[1], SP[2])) {
+      pc++;
+    }
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(Jump, 0);
+    const int32_t target = static_cast<int32_t>(op) >> 8;
+    pc += (target - 1);
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(StoreIndexedTOS, 0);
+    SP -= 3;
+    RawArray* array = static_cast<RawArray*>(SP[1]);
+    RawSmi* index = static_cast<RawSmi*>(SP[2]);
+    RawObject* value = SP[3];
+    ASSERT(array->GetClassId() == kArrayCid);
+    ASSERT(!index->IsHeapObject());
+    array->StorePointer(array->ptr()->data() + Smi::Value(index), value);
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(Trap, 0);
+    UNIMPLEMENTED();
+    DISPATCH();
+  }
+
+  // Helper used to handle noSuchMethod on closures.
+  {
+  ClosureNoSuchMethod:
+#if defined(DEBUG)
+    function_h ^= FrameFunction(FP);
+    ASSERT(function_h.IsClosureFunction());
+#endif
+
+    // Restore caller context as we are going to throw NoSuchMethod.
+    pc = SavedCallerPC(FP);
+
+    const bool has_dart_caller = (reinterpret_cast<uword>(pc) & 2) == 0;
+    const intptr_t argc = has_dart_caller
+                              ? Bytecode::DecodeArgc(pc[-1])
+                              : (reinterpret_cast<uword>(pc) >> 2);
+
+    SP = FrameArguments(FP, 0);
+    RawObject** args = SP - argc;
+    FP = SavedCallerFP(FP);
+    if (has_dart_caller) {
+      pp = FrameCode(FP)->ptr()->object_pool_->ptr();
+    }
+
+    *++SP = null_value;
+    *++SP = args[0];  // Closure object.
+    *++SP = argdesc;
+    *++SP = null_value;  // Array of arguments (will be filled).
+
+    // Allocate array of arguments.
+    {
+      SP[1] = Smi::New(argc);  // length
+      SP[2] = null_value;      // type
+      Exit(thread, FP, SP + 3, pc);
+      NativeArguments native_args(thread, 2, SP + 1, SP);
+      INVOKE_RUNTIME(DRT_AllocateArray, native_args);
+
+      // Copy arguments into the newly allocated array.
+      RawArray* array = static_cast<RawArray*>(SP[0]);
+      ASSERT(array->GetClassId() == kArrayCid);
+      for (intptr_t i = 0; i < argc; i++) {
+        array->ptr()->data()[i] = args[i];
+      }
+    }
+
+    // Invoke noSuchMethod passing down closure, argument descriptor and
+    // array of arguments.
+    {
+      Exit(thread, FP, SP + 1, pc);
+      NativeArguments native_args(thread, 3, SP - 2, SP - 3);
+      INVOKE_RUNTIME(DRT_InvokeClosureNoSuchMethod, native_args);
+      UNREACHABLE();
+    }
+
+    DISPATCH();
+  }
+
+  // Single dispatch point used by exception handling macros.
+  {
+  DispatchAfterException:
+    DISPATCH();
+  }
+
+  UNREACHABLE();
+  return 0;
+}
+
+void Simulator::Longjmp(uword pc,
+                        uword sp,
+                        uword fp,
+                        RawObject* raw_exception,
+                        RawObject* raw_stacktrace,
+                        Thread* thread) {
+  // Walk over all setjmp buffers (simulated --> C++ transitions)
+  // and try to find the setjmp associated with the simulated stack pointer.
+  SimulatorSetjmpBuffer* buf = last_setjmp_buffer();
+  while ((buf->link() != NULL) && (buf->link()->fp() > fp)) {
+    buf = buf->link();
+  }
+  ASSERT(buf != NULL);
+  ASSERT(last_setjmp_buffer() == buf);
+
+  // The C++ caller has not cleaned up the stack memory of C++ frames.
+  // Prepare for unwinding frames by destroying all the stack resources
+  // in the previous C++ frames.
+  StackResource::Unwind(thread);
+
+  // Set the tag.
+  thread->set_vm_tag(VMTag::kDartTagId);
+  // Clear top exit frame.
+  thread->set_top_exit_frame_info(0);
+
+  ASSERT(raw_exception != Object::null());
+  sp_ = reinterpret_cast<RawObject**>(sp);
+  fp_ = reinterpret_cast<RawObject**>(fp);
+  pc_ = pc;
+  special_[kExceptionSpecialIndex] = raw_exception;
+  special_[kStacktraceSpecialIndex] = raw_stacktrace;
+  buf->Longjmp();
+  UNREACHABLE();
+}
+
+}  // namespace dart
+
+
+#endif  // defined TARGET_ARCH_DBC