// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/base/memory.h"
#include "src/common/message-template.h"
#include "src/compiler/wasm-compiler.h"
#include "src/debug/debug.h"
#include "src/execution/arguments-inl.h"
#include "src/execution/frame-constants.h"
#include "src/execution/frames.h"
#include "src/heap/factory.h"
#include "src/logging/counters.h"
#include "src/numbers/conversions.h"
#include "src/objects/frame-array-inl.h"
#include "src/objects/objects-inl.h"
#include "src/runtime/runtime-utils.h"
#include "src/trap-handler/trap-handler.h"
#include "src/wasm/module-compiler.h"
#include "src/wasm/wasm-code-manager.h"
#include "src/wasm/wasm-constants.h"
#include "src/wasm/wasm-debug.h"
#include "src/wasm/wasm-engine.h"
#include "src/wasm/wasm-objects.h"
#include "src/wasm/wasm-value.h"

namespace v8 {
namespace internal {

namespace {

template <typename FrameType, StackFrame::Type... skipped_frame_types>
class FrameFinder {
  static_assert(sizeof...(skipped_frame_types) > 0,
                "Specify at least one frame to skip");

 public:
  explicit FrameFinder(Isolate* isolate)
      : frame_iterator_(isolate, isolate->thread_local_top()) {
    for (auto type : {skipped_frame_types...}) {
      DCHECK_EQ(type, frame_iterator_.frame()->type());
      USE(type);
      frame_iterator_.Advance();
    }
    // Type check the frame where the iterator stopped now.
    DCHECK_NOT_NULL(frame());
  }

  FrameType* frame() { return FrameType::cast(frame_iterator_.frame()); }

 private:
  StackFrameIterator frame_iterator_;
};

WasmInstanceObject GetWasmInstanceOnStackTop(Isolate* isolate) {
  return FrameFinder<WasmCompiledFrame, StackFrame::EXIT>(isolate)
      .frame()
      ->wasm_instance();
}

Context GetNativeContextFromWasmInstanceOnStackTop(Isolate* isolate) {
  return GetWasmInstanceOnStackTop(isolate).native_context();
}

class ClearThreadInWasmScope {
 public:
  ClearThreadInWasmScope() {
    DCHECK_EQ(trap_handler::IsTrapHandlerEnabled(),
              trap_handler::IsThreadInWasm());
    trap_handler::ClearThreadInWasm();
  }
  ~ClearThreadInWasmScope() {
    DCHECK(!trap_handler::IsThreadInWasm());
    trap_handler::SetThreadInWasm();
  }
};

Object ThrowWasmError(Isolate* isolate, MessageTemplate message) {
  HandleScope scope(isolate);
  Handle<JSObject> error_obj = isolate->factory()->NewWasmRuntimeError(message);
  JSObject::AddProperty(isolate, error_obj,
                        isolate->factory()->wasm_uncatchable_symbol(),
                        isolate->factory()->true_value(), NONE);
  return isolate->Throw(*error_obj);
}
}  // namespace

RUNTIME_FUNCTION(Runtime_WasmIsValidFuncRefValue) {
  HandleScope scope(isolate);
  DCHECK_EQ(1, args.length());
  CONVERT_ARG_HANDLE_CHECKED(Object, function, 0);

  if (function->IsNull(isolate)) {
    return Smi::FromInt(true);
  }
  if (WasmExternalFunction::IsWasmExternalFunction(*function)) {
    return Smi::FromInt(true);
  }
  return Smi::FromInt(false);
}

RUNTIME_FUNCTION(Runtime_WasmMemoryGrow) {
  HandleScope scope(isolate);
  DCHECK_EQ(2, args.length());
  CONVERT_ARG_HANDLE_CHECKED(WasmInstanceObject, instance, 0);
  // {delta_pages} is checked to be a positive smi in the WasmMemoryGrow builtin
  // which calls this runtime function.
  CONVERT_UINT32_ARG_CHECKED(delta_pages, 1);

  // This runtime function is always being called from wasm code.
  ClearThreadInWasmScope flag_scope;

  int ret = WasmMemoryObject::Grow(
      isolate, handle(instance->memory_object(), isolate), delta_pages);
  // The WasmMemoryGrow builtin which calls this runtime function expects us to
  // always return a Smi.
  return Smi::FromInt(ret);
}

RUNTIME_FUNCTION(Runtime_ThrowWasmError) {
  ClearThreadInWasmScope clear_wasm_flag;
  DCHECK_EQ(1, args.length());
  CONVERT_SMI_ARG_CHECKED(message_id, 0);
  return ThrowWasmError(isolate, MessageTemplateFromInt(message_id));
}

RUNTIME_FUNCTION(Runtime_ThrowWasmStackOverflow) {
  SealHandleScope shs(isolate);
  DCHECK_LE(0, args.length());
  return isolate->StackOverflow();
}

RUNTIME_FUNCTION(Runtime_WasmThrowTypeError) {
  HandleScope scope(isolate);
  DCHECK_EQ(0, args.length());
  THROW_NEW_ERROR_RETURN_FAILURE(
      isolate, NewTypeError(MessageTemplate::kWasmTrapTypeError));
}

RUNTIME_FUNCTION(Runtime_WasmThrowCreate) {
  // TODO(kschimpf): Can this be replaced with equivalent TurboFan code/calls.
  HandleScope scope(isolate);
  DCHECK_EQ(2, args.length());
  DCHECK(isolate->context().is_null());
  isolate->set_context(GetNativeContextFromWasmInstanceOnStackTop(isolate));
  CONVERT_ARG_CHECKED(WasmExceptionTag, tag_raw, 0);
  CONVERT_SMI_ARG_CHECKED(size, 1);
  // TODO(wasm): Manually box because parameters are not visited yet.
  Handle<Object> tag(tag_raw, isolate);
  Handle<Object> exception = isolate->factory()->NewWasmRuntimeError(
      MessageTemplate::kWasmExceptionError);
  CHECK(!Object::SetProperty(isolate, exception,
                             isolate->factory()->wasm_exception_tag_symbol(),
                             tag, StoreOrigin::kMaybeKeyed,
                             Just(ShouldThrow::kThrowOnError))
             .is_null());
  Handle<FixedArray> values = isolate->factory()->NewFixedArray(size);
  CHECK(!Object::SetProperty(isolate, exception,
                             isolate->factory()->wasm_exception_values_symbol(),
                             values, StoreOrigin::kMaybeKeyed,
                             Just(ShouldThrow::kThrowOnError))
             .is_null());
  return *exception;
}

RUNTIME_FUNCTION(Runtime_WasmExceptionGetTag) {
  // TODO(kschimpf): Can this be replaced with equivalent TurboFan code/calls.
  HandleScope scope(isolate);
  DCHECK_EQ(1, args.length());
  DCHECK(isolate->context().is_null());
  isolate->set_context(GetNativeContextFromWasmInstanceOnStackTop(isolate));
  CONVERT_ARG_CHECKED(Object, except_obj_raw, 0);
  // TODO(wasm): Manually box because parameters are not visited yet.
  Handle<Object> except_obj(except_obj_raw, isolate);
  if (!except_obj->IsWasmExceptionPackage(isolate)) {
    return ReadOnlyRoots(isolate).undefined_value();
  }
  Handle<WasmExceptionPackage> exception =
      Handle<WasmExceptionPackage>::cast(except_obj);
  return *WasmExceptionPackage::GetExceptionTag(isolate, exception);
}

RUNTIME_FUNCTION(Runtime_WasmExceptionGetValues) {
  // TODO(kschimpf): Can this be replaced with equivalent TurboFan code/calls.
  HandleScope scope(isolate);
  DCHECK_EQ(1, args.length());
  DCHECK(isolate->context().is_null());
  isolate->set_context(GetNativeContextFromWasmInstanceOnStackTop(isolate));
  CONVERT_ARG_CHECKED(Object, except_obj_raw, 0);
  // TODO(wasm): Manually box because parameters are not visited yet.
  Handle<Object> except_obj(except_obj_raw, isolate);
  if (!except_obj->IsWasmExceptionPackage(isolate)) {
    return ReadOnlyRoots(isolate).undefined_value();
  }
  Handle<WasmExceptionPackage> exception =
      Handle<WasmExceptionPackage>::cast(except_obj);
  return *WasmExceptionPackage::GetExceptionValues(isolate, exception);
}

RUNTIME_FUNCTION(Runtime_WasmRunInterpreter) {
  DCHECK_EQ(2, args.length());
  HandleScope scope(isolate);
  CONVERT_NUMBER_CHECKED(int32_t, func_index, Int32, args[0]);
  CONVERT_ARG_HANDLE_CHECKED(Object, arg_buffer_obj, 1);

  // The arg buffer is the raw pointer to the caller's stack. It looks like a
  // Smi (lowest bit not set, as checked by IsSmi), but is no valid Smi. We just
  // cast it back to the raw pointer.
  CHECK(!arg_buffer_obj->IsHeapObject());
  CHECK(arg_buffer_obj->IsSmi());
  Address arg_buffer = arg_buffer_obj->ptr();

  ClearThreadInWasmScope wasm_flag;

  // Find the frame pointer and instance of the interpreter frame on the stack.
  Handle<WasmInstanceObject> instance;
  Address frame_pointer = 0;
  {
    FrameFinder<WasmInterpreterEntryFrame, StackFrame::EXIT> frame_finder(
        isolate);
    instance = handle(frame_finder.frame()->wasm_instance(), isolate);
    frame_pointer = frame_finder.frame()->fp();
  }

  // Reserve buffers for argument and return values.
  DCHECK_GE(instance->module()->functions.size(), func_index);
  const wasm::FunctionSig* sig = instance->module()->functions[func_index].sig;
  DCHECK_GE(kMaxInt, sig->parameter_count());
  int num_params = static_cast<int>(sig->parameter_count());
  ScopedVector<wasm::WasmValue> wasm_args(num_params);
  DCHECK_GE(kMaxInt, sig->return_count());
  int num_returns = static_cast<int>(sig->return_count());
  ScopedVector<wasm::WasmValue> wasm_rets(num_returns);

  // Copy the arguments for the {arg_buffer} into a vector of {WasmValue}. This
  // also boxes reference types into handles, which needs to happen before any
  // methods that could trigger a GC are being called.
  Address arg_buf_ptr = arg_buffer;
  for (int i = 0; i < num_params; ++i) {
#define CASE_ARG_TYPE(type, ctype)                                     \
  case wasm::ValueType::type:                                          \
    DCHECK_EQ(sig->GetParam(i).element_size_bytes(), sizeof(ctype));   \
    wasm_args[i] =                                                     \
        wasm::WasmValue(base::ReadUnalignedValue<ctype>(arg_buf_ptr)); \
    arg_buf_ptr += sizeof(ctype);                                      \
    break;
    switch (sig->GetParam(i).kind()) {
      CASE_ARG_TYPE(kI32, uint32_t)
      CASE_ARG_TYPE(kI64, uint64_t)
      CASE_ARG_TYPE(kF32, float)
      CASE_ARG_TYPE(kF64, double)
#undef CASE_ARG_TYPE
      case wasm::ValueType::kAnyRef:
      case wasm::ValueType::kFuncRef:
      case wasm::ValueType::kNullRef:
      case wasm::ValueType::kExnRef: {
        DCHECK_EQ(sig->GetParam(i).element_size_bytes(), kSystemPointerSize);
        Handle<Object> ref(
            Object(base::ReadUnalignedValue<Address>(arg_buf_ptr)), isolate);
        DCHECK_IMPLIES(sig->GetParam(i) == wasm::kWasmNullRef, ref->IsNull());
        wasm_args[i] = wasm::WasmValue(ref);
        arg_buf_ptr += kSystemPointerSize;
        break;
      }
      case wasm::ValueType::kStmt:
      case wasm::ValueType::kS128:
      case wasm::ValueType::kBottom:
        UNREACHABLE();
    }
  }

  // Set the current isolate's context.
  DCHECK(isolate->context().is_null());
  isolate->set_context(instance->native_context());

  // Run the function in the interpreter. Note that neither the {WasmDebugInfo}
  // nor the {InterpreterHandle} have to exist, because interpretation might
  // have been triggered by another Isolate sharing the same WasmEngine.
  Handle<WasmDebugInfo> debug_info =
      WasmInstanceObject::GetOrCreateDebugInfo(instance);
  bool success = WasmDebugInfo::RunInterpreter(
      isolate, debug_info, frame_pointer, func_index, wasm_args, wasm_rets);

  // Early return on failure.
  if (!success) {
    DCHECK(isolate->has_pending_exception());
    return ReadOnlyRoots(isolate).exception();
  }

  // Copy return values from the vector of {WasmValue} into {arg_buffer}. This
  // also un-boxes reference types from handles into raw pointers.
  arg_buf_ptr = arg_buffer;
  for (int i = 0; i < num_returns; ++i) {
#define CASE_RET_TYPE(type, ctype)                                           \
  case wasm::ValueType::type:                                                \
    DCHECK_EQ(sig->GetReturn(i).element_size_bytes(), sizeof(ctype));        \
    base::WriteUnalignedValue<ctype>(arg_buf_ptr, wasm_rets[i].to<ctype>()); \
    arg_buf_ptr += sizeof(ctype);                                            \
    break;
    switch (sig->GetReturn(i).kind()) {
      CASE_RET_TYPE(kI32, uint32_t)
      CASE_RET_TYPE(kI64, uint64_t)
      CASE_RET_TYPE(kF32, float)
      CASE_RET_TYPE(kF64, double)
#undef CASE_RET_TYPE
      case wasm::ValueType::kAnyRef:
      case wasm::ValueType::kFuncRef:
      case wasm::ValueType::kNullRef:
      case wasm::ValueType::kExnRef: {
        DCHECK_EQ(sig->GetReturn(i).element_size_bytes(), kSystemPointerSize);
        DCHECK_IMPLIES(sig->GetReturn(i) == wasm::kWasmNullRef,
                       wasm_rets[i].to_anyref()->IsNull());
        base::WriteUnalignedValue<Object>(arg_buf_ptr,
                                          *wasm_rets[i].to_anyref());
        arg_buf_ptr += kSystemPointerSize;
        break;
      }
      default:
        UNREACHABLE();
    }
  }

  return ReadOnlyRoots(isolate).undefined_value();
}

RUNTIME_FUNCTION(Runtime_WasmStackGuard) {
  SealHandleScope shs(isolate);
  DCHECK_EQ(0, args.length());
  DCHECK(!trap_handler::IsTrapHandlerEnabled() ||
         trap_handler::IsThreadInWasm());

  ClearThreadInWasmScope wasm_flag;

  // Check if this is a real stack overflow.
  StackLimitCheck check(isolate);
  if (check.JsHasOverflowed()) return isolate->StackOverflow();

  return isolate->stack_guard()->HandleInterrupts();
}

RUNTIME_FUNCTION(Runtime_WasmCompileLazy) {
  HandleScope scope(isolate);
  DCHECK_EQ(2, args.length());
  CONVERT_ARG_HANDLE_CHECKED(WasmInstanceObject, instance, 0);
  CONVERT_SMI_ARG_CHECKED(func_index, 1);

  // This runtime function is always called from wasm code.
  ClearThreadInWasmScope flag_scope;

#ifdef DEBUG
  FrameFinder<WasmCompileLazyFrame, StackFrame::EXIT> frame_finder(isolate);
  DCHECK_EQ(*instance, frame_finder.frame()->wasm_instance());
#endif

  DCHECK(isolate->context().is_null());
  isolate->set_context(instance->native_context());
  auto* native_module = instance->module_object().native_module();
  bool success = wasm::CompileLazy(isolate, native_module, func_index);
  if (!success) {
    DCHECK(isolate->has_pending_exception());
    return ReadOnlyRoots(isolate).exception();
  }

  Address entrypoint = native_module->GetCallTargetForFunction(func_index);

  return Object(entrypoint);
}

// Should be called from within a handle scope
Handle<JSArrayBuffer> getSharedArrayBuffer(Handle<WasmInstanceObject> instance,
                                           Isolate* isolate, uint32_t address) {
  DCHECK(instance->has_memory_object());
  Handle<JSArrayBuffer> array_buffer(instance->memory_object().array_buffer(),
                                     isolate);

  // Validation should have failed if the memory was not shared.
  DCHECK(array_buffer->is_shared());

  // Should have trapped if address was OOB
  DCHECK_LT(address, array_buffer->byte_length());
  return array_buffer;
}

RUNTIME_FUNCTION(Runtime_WasmAtomicNotify) {
  ClearThreadInWasmScope clear_wasm_flag;
  HandleScope scope(isolate);
  DCHECK_EQ(3, args.length());
  CONVERT_ARG_HANDLE_CHECKED(WasmInstanceObject, instance, 0);
  CONVERT_NUMBER_CHECKED(uint32_t, address, Uint32, args[1]);
  CONVERT_NUMBER_CHECKED(uint32_t, count, Uint32, args[2]);
  Handle<JSArrayBuffer> array_buffer =
      getSharedArrayBuffer(instance, isolate, address);
  return FutexEmulation::Wake(array_buffer, address, count);
}

RUNTIME_FUNCTION(Runtime_WasmI32AtomicWait) {
  ClearThreadInWasmScope clear_wasm_flag;
  HandleScope scope(isolate);
  DCHECK_EQ(4, args.length());
  CONVERT_ARG_HANDLE_CHECKED(WasmInstanceObject, instance, 0);
  CONVERT_NUMBER_CHECKED(uint32_t, address, Uint32, args[1]);
  CONVERT_NUMBER_CHECKED(int32_t, expected_value, Int32, args[2]);
  CONVERT_ARG_HANDLE_CHECKED(BigInt, timeout_ns, 3);

  Handle<JSArrayBuffer> array_buffer =
      getSharedArrayBuffer(instance, isolate, address);
  return FutexEmulation::WaitWasm32(isolate, array_buffer, address,
                                    expected_value, timeout_ns->AsInt64());
}

RUNTIME_FUNCTION(Runtime_WasmI64AtomicWait) {
  ClearThreadInWasmScope clear_wasm_flag;
  HandleScope scope(isolate);
  DCHECK_EQ(4, args.length());
  CONVERT_ARG_HANDLE_CHECKED(WasmInstanceObject, instance, 0);
  CONVERT_NUMBER_CHECKED(uint32_t, address, Uint32, args[1]);
  CONVERT_ARG_HANDLE_CHECKED(BigInt, expected_value, 2);
  CONVERT_ARG_HANDLE_CHECKED(BigInt, timeout_ns, 3);

  Handle<JSArrayBuffer> array_buffer =
      getSharedArrayBuffer(instance, isolate, address);
  return FutexEmulation::WaitWasm64(isolate, array_buffer, address,
                                    expected_value->AsInt64(),
                                    timeout_ns->AsInt64());
}

namespace {
Object ThrowTableOutOfBounds(Isolate* isolate,
                             Handle<WasmInstanceObject> instance) {
  // Handle out-of-bounds access here in the runtime call, rather
  // than having the lower-level layers deal with JS exceptions.
  if (isolate->context().is_null()) {
    isolate->set_context(instance->native_context());
  }
  Handle<Object> error_obj = isolate->factory()->NewWasmRuntimeError(
      MessageTemplate::kWasmTrapTableOutOfBounds);
  return isolate->Throw(*error_obj);
}
}  // namespace

RUNTIME_FUNCTION(Runtime_WasmRefFunc) {
  // This runtime function is always being called from wasm code.
  ClearThreadInWasmScope flag_scope;
  HandleScope scope(isolate);
  DCHECK_EQ(1, args.length());
  auto instance =
      Handle<WasmInstanceObject>(GetWasmInstanceOnStackTop(isolate), isolate);
  DCHECK(isolate->context().is_null());
  isolate->set_context(instance->native_context());
  CONVERT_UINT32_ARG_CHECKED(function_index, 0);

  Handle<WasmExternalFunction> function =
      WasmInstanceObject::GetOrCreateWasmExternalFunction(isolate, instance,
                                                          function_index);

  return *function;
}

RUNTIME_FUNCTION(Runtime_WasmFunctionTableGet) {
  // This runtime function is always being called from wasm code.
  ClearThreadInWasmScope flag_scope;

  HandleScope scope(isolate);
  DCHECK_EQ(3, args.length());
  CONVERT_ARG_HANDLE_CHECKED(WasmInstanceObject, instance, 0);
  CONVERT_UINT32_ARG_CHECKED(table_index, 1);
  CONVERT_UINT32_ARG_CHECKED(entry_index, 2);
  DCHECK_LT(table_index, instance->tables().length());
  auto table = handle(
      WasmTableObject::cast(instance->tables().get(table_index)), isolate);

  if (!WasmTableObject::IsInBounds(isolate, table, entry_index)) {
    return ThrowWasmError(isolate, MessageTemplate::kWasmTrapTableOutOfBounds);
  }

  return *WasmTableObject::Get(isolate, table, entry_index);
}

RUNTIME_FUNCTION(Runtime_WasmFunctionTableSet) {
  // This runtime function is always being called from wasm code.
  ClearThreadInWasmScope flag_scope;

  HandleScope scope(isolate);
  DCHECK_EQ(4, args.length());
  CONVERT_ARG_HANDLE_CHECKED(WasmInstanceObject, instance, 0);
  CONVERT_UINT32_ARG_CHECKED(table_index, 1);
  CONVERT_UINT32_ARG_CHECKED(entry_index, 2);
  CONVERT_ARG_CHECKED(Object, element_raw, 3);
  // TODO(wasm): Manually box because parameters are not visited yet.
  Handle<Object> element(element_raw, isolate);
  DCHECK_LT(table_index, instance->tables().length());
  auto table = handle(
      WasmTableObject::cast(instance->tables().get(table_index)), isolate);

  if (!WasmTableObject::IsInBounds(isolate, table, entry_index)) {
    return ThrowWasmError(isolate, MessageTemplate::kWasmTrapTableOutOfBounds);
  }
  WasmTableObject::Set(isolate, table, entry_index, element);
  return ReadOnlyRoots(isolate).undefined_value();
}

RUNTIME_FUNCTION(Runtime_WasmTableInit) {
  HandleScope scope(isolate);
  DCHECK_EQ(6, args.length());
  CONVERT_ARG_HANDLE_CHECKED(WasmInstanceObject, instance, 0);
  CONVERT_UINT32_ARG_CHECKED(table_index, 1);
  CONVERT_UINT32_ARG_CHECKED(elem_segment_index, 2);
  CONVERT_UINT32_ARG_CHECKED(dst, 3);
  CONVERT_UINT32_ARG_CHECKED(src, 4);
  CONVERT_UINT32_ARG_CHECKED(count, 5);

  DCHECK(!isolate->context().is_null());

  bool oob = !WasmInstanceObject::InitTableEntries(
      isolate, instance, table_index, elem_segment_index, dst, src, count);
  if (oob) return ThrowTableOutOfBounds(isolate, instance);
  return ReadOnlyRoots(isolate).undefined_value();
}

RUNTIME_FUNCTION(Runtime_WasmTableCopy) {
  HandleScope scope(isolate);
  DCHECK_EQ(6, args.length());
  CONVERT_ARG_HANDLE_CHECKED(WasmInstanceObject, instance, 0);
  CONVERT_UINT32_ARG_CHECKED(table_dst_index, 1);
  CONVERT_UINT32_ARG_CHECKED(table_src_index, 2);
  CONVERT_UINT32_ARG_CHECKED(dst, 3);
  CONVERT_UINT32_ARG_CHECKED(src, 4);
  CONVERT_UINT32_ARG_CHECKED(count, 5);

  DCHECK(!isolate->context().is_null());

  bool oob = !WasmInstanceObject::CopyTableEntries(
      isolate, instance, table_dst_index, table_src_index, dst, src, count);
  if (oob) return ThrowTableOutOfBounds(isolate, instance);
  return ReadOnlyRoots(isolate).undefined_value();
}

RUNTIME_FUNCTION(Runtime_WasmTableGrow) {
  HandleScope scope(isolate);
  DCHECK_EQ(3, args.length());
  auto instance =
      Handle<WasmInstanceObject>(GetWasmInstanceOnStackTop(isolate), isolate);
  CONVERT_UINT32_ARG_CHECKED(table_index, 0);
  CONVERT_ARG_CHECKED(Object, value_raw, 1);
  // TODO(wasm): Manually box because parameters are not visited yet.
  Handle<Object> value(value_raw, isolate);
  CONVERT_UINT32_ARG_CHECKED(delta, 2);

  Handle<WasmTableObject> table(
      WasmTableObject::cast(instance->tables().get(table_index)), isolate);
  int result = WasmTableObject::Grow(isolate, table, delta, value);

  return Smi::FromInt(result);
}

RUNTIME_FUNCTION(Runtime_WasmTableFill) {
  HandleScope scope(isolate);
  DCHECK_EQ(4, args.length());
  auto instance =
      Handle<WasmInstanceObject>(GetWasmInstanceOnStackTop(isolate), isolate);
  CONVERT_UINT32_ARG_CHECKED(table_index, 0);
  CONVERT_UINT32_ARG_CHECKED(start, 1);
  CONVERT_ARG_CHECKED(Object, value_raw, 2);
  // TODO(wasm): Manually box because parameters are not visited yet.
  Handle<Object> value(value_raw, isolate);
  CONVERT_UINT32_ARG_CHECKED(count, 3);

  Handle<WasmTableObject> table(
      WasmTableObject::cast(instance->tables().get(table_index)), isolate);

  uint32_t table_size = table->current_length();

  if (start > table_size) {
    return ThrowTableOutOfBounds(isolate, instance);
  }

  // Even when table.fill goes out-of-bounds, as many entries as possible are
  // put into the table. Only afterwards we trap.
  uint32_t fill_count = std::min(count, table_size - start);
  if (fill_count < count) {
    return ThrowTableOutOfBounds(isolate, instance);
  }
  WasmTableObject::Fill(isolate, table, start, value, fill_count);

  return ReadOnlyRoots(isolate).undefined_value();
}

RUNTIME_FUNCTION(Runtime_WasmNewMultiReturnFixedArray) {
  DCHECK_EQ(1, args.length());
  HandleScope scope(isolate);
  CONVERT_INT32_ARG_CHECKED(size, 0);
  Handle<FixedArray> fixed_array = isolate->factory()->NewFixedArray(size);
  return *fixed_array;
}

RUNTIME_FUNCTION(Runtime_WasmNewMultiReturnJSArray) {
  HandleScope scope(isolate);
  DCHECK_EQ(1, args.length());
  DCHECK(!isolate->context().is_null());
  CONVERT_ARG_CHECKED(FixedArray, fixed_array, 0);
  Handle<FixedArray> fixed_array_handle(fixed_array, isolate);
  Handle<JSArray> array = isolate->factory()->NewJSArrayWithElements(
      fixed_array_handle, PACKED_ELEMENTS);
  return *array;
}

RUNTIME_FUNCTION(Runtime_WasmDebugBreak) {
  HandleScope scope(isolate);
  DCHECK_EQ(0, args.length());
  FrameFinder<WasmCompiledFrame, StackFrame::EXIT, StackFrame::WASM_DEBUG_BREAK>
      frame_finder(isolate);
  auto instance = handle(frame_finder.frame()->wasm_instance(), isolate);
  int position = frame_finder.frame()->position();
  isolate->set_context(instance->native_context());

  // Enter the debugger.
  DebugScope debug_scope(isolate->debug());

  const auto undefined = ReadOnlyRoots(isolate).undefined_value();
  WasmCompiledFrame* frame = frame_finder.frame();
  auto* debug_info = frame->native_module()->GetDebugInfo();
  if (debug_info->IsStepping(frame)) {
    debug_info->ClearStepping();
    isolate->debug()->ClearStepping();
    isolate->debug()->OnDebugBreak(isolate->factory()->empty_fixed_array());
    return undefined;
  }

  // Check whether we hit a breakpoint.
  Handle<Script> script(instance->module_object().script(), isolate);
  Handle<FixedArray> breakpoints;
  if (WasmScript::CheckBreakPoints(isolate, script, position)
          .ToHandle(&breakpoints)) {
    debug_info->ClearStepping();
    isolate->debug()->ClearStepping();
    if (isolate->debug()->break_points_active()) {
      // We hit one or several breakpoints. Notify the debug listeners.
      isolate->debug()->OnDebugBreak(breakpoints);
    }
  } else {
    // Unused breakpoint. Possible scenarios:
    // 1. We hit a breakpoint that was already removed,
    // 2. We hit a stepping breakpoint after resuming,
    // 3. We hit a stepping breakpoint during a stepOver on a recursive call.
    // 4. The breakpoint was set in a different isolate.
    // We can handle the first three cases by simply removing the breakpoint (if
    // it exists), since this will also recompile the function without the
    // stepping breakpoints.
    // TODO(thibaudm/clemensb): handle case 4.
    debug_info->RemoveBreakpoint(frame->function_index(), position, isolate);
  }

  return undefined;
}

}  // namespace internal
}  // namespace v8