operation.h

#ifndef IV_LV5_RAILGUN_OPERATION_H_
#define IV_LV5_RAILGUN_OPERATION_H_
#include <iv/arith.h>
#include <iv/platform_math.h>
#include <iv/lv5/arguments.h>
#include <iv/lv5/jsval.h>
#include <iv/lv5/chain.h>
#include <iv/lv5/railgun/fwd.h>
#include <iv/lv5/railgun/instruction_fwd.h>
namespace iv {
namespace lv5 {
namespace railgun {
namespace detail {

template<int Target>
inline bool IsIncrementOverflowSafe(int32_t val);

template<>
inline bool IsIncrementOverflowSafe<-1>(int32_t val) {
  return val > INT32_MIN;
}

template<>
inline bool IsIncrementOverflowSafe<1>(int32_t val) {
  return val < INT32_MAX;
}

class VMArguments : public lv5::Arguments {
 public:
  VMArguments(lv5::Context* ctx, pointer ptr, std::size_t n)
    : lv5::Arguments(ctx, ptr, n) {
  }
};

}  // namespace detail

class Operation {
 public:
  explicit Operation(lv5::Context* ctx) : ctx_(ctx) { }

  JSVal Invoke(JSFunction* func, JSVal* arg, int argc_with_this, Error* e) {
    detail::VMArguments args(ctx_,
                             arg + (argc_with_this - 1),
                             argc_with_this - 1);
    return func->Call(&args, args.this_binding(), e);
  }

  JSVal InvokeMaybeEval(JSFunction* func,
                        JSVal* arg, int argc_with_this,
                        Frame* prev, Error* e) {
    detail::VMArguments args(ctx_,
                             arg + (argc_with_this - 1),
                             argc_with_this - 1);
    const JSAPI native = func->NativeFunction();
    if (native && native == &GlobalEval) {
      // direct call to eval point
      args.set_this_binding(args.this_binding());
      return DirectCallToEval(args, prev, e);
    }
    return func->Call(&args, args.this_binding(), e);
  }

  JSVal Construct(JSFunction* func, JSVal* arg, int argc_with_this, Error* e) {
    detail::VMArguments args(ctx_,
                             arg + (argc_with_this - 1),
                             argc_with_this - 1);
    args.set_constructor_call(true);
    return func->Construct(&args, e);
  }

  void RaiseReferenceError(Symbol name, Error* e) const {
    core::UStringBuilder builder;
    builder.Append('"');
    builder.Append(symbol::GetSymbolString(name));
    builder.Append("\" not defined");
    e->Report(Error::Reference, builder.BuildPiece());
  }

  void RaiseReferenceError(Error* e) const {
    core::UStringBuilder builder;
    builder.Append("Invalid left-hand side expression");
    e->Report(Error::Reference, builder.BuildPiece());
  }

  JSEnv* GetEnv(JSEnv* env, Symbol name) const {
    JSEnv* current = env;
    while (current) {
      if (current->HasBinding(ctx_, name)) {
        return current;
      } else {
        current = current->outer();
      }
    }
    return NULL;
  }

  JSDeclEnv* GetHeapEnv(JSEnv* env, uint32_t scope_nest_count) const {
    for (uint32_t i = 0; i < scope_nest_count; ++i) {
      env = env->outer();
    }
    assert(env->AsJSDeclEnv());
    return static_cast<JSDeclEnv*>(env);
  }

#define CHECK IV_LV5_ERROR_WITH(e, JSEmpty)

  JSVal LoadName(JSEnv* env, Symbol name, bool strict, Error* e) {
    if (JSEnv* current = GetEnv(env, name)) {
      return current->GetBindingValue(ctx_, name, strict, e);
    }
    RaiseReferenceError(name, e);
    return JSEmpty;
  }

  JSVal LoadHeap(JSEnv* env, Symbol name,
                 bool strict, uint32_t offset,
                 uint32_t scope_nest_count, Error* e) {
    return GetHeapEnv(env, scope_nest_count)->GetByOffset(offset, strict, e);
  }

  JSVal LoadProp(JSVal base, Symbol s, bool strict, Error* e) {
    base.CheckObjectCoercible(CHECK);
    return LoadPropImpl(base, s, strict, e);
  }

  template<OP::Type own, OP::Type proto, OP::Type chain, OP::Type generic>
  JSVal LoadProp(Instruction* instr,
                 JSVal base, Symbol s, bool strict, Error* e) {
    // opcode | (dst | base | name) | nop | nop | nop
    base.CheckObjectCoercible(CHECK);
    Slot slot;
    const JSVal res = base.GetSlot(ctx_, s, &slot, IV_LV5_ERROR(e));

    if (slot.IsNotFound()) {
      return res;
    }

    // property found
    if (!slot.IsLoadCacheable() || symbol::IsArrayIndexSymbol(s)) {
      // bailout to generic
      instr[0] = Instruction::GetOPInstruction(generic);
      return slot.Get(ctx_, base, e);
    }

    assert(!symbol::IsArrayIndexSymbol(s));

    JSObject* obj = NULL;
    if (base.IsPrimitive()) {
      // if base is primitive, property not found in "this" object
      // so, lookup from proto
      obj = base.GetPrimitiveProto(ctx_);
    } else {
      obj = base.object();
    }

    // cache phase
    // own property / proto property / chain lookup property
    if (slot.base() == obj) {
      // own property
      instr[0] = Instruction::GetOPInstruction(own);
      instr[2].map = obj->map();
      instr[3].u32[0] = slot.offset();
      return slot.value();
    }

    if (slot.base() == obj->prototype()) {
      // proto property
      obj->FlattenMap();
      instr[0] = Instruction::GetOPInstruction(proto);
      instr[2].map = obj->map();
      instr[3].map = slot.base()->map();
      instr[4].u32[0] = slot.offset();
      return slot.value();
    }

    // chain property
    instr[0] = Instruction::GetOPInstruction(chain);
    instr[2].chain = Chain::New(obj, slot.base());
    instr[3].map = slot.base()->map();
    instr[4].u32[0] = slot.offset();
    return slot.value();
  }

  JSVal LoadElement(JSVal base,
                    JSVal element, bool strict, Error* e) {
    base.CheckObjectCoercible(CHECK);
    const Symbol s = element.ToSymbol(ctx_, CHECK);
    return LoadPropImpl(base, s, strict, e);
  }

  JSVal LoadPropImpl(JSVal base,
                     Symbol s, bool strict, Error* e) {
    if (base.IsPrimitive()) {
      return LoadPropPrimitive(base, s, strict, e);
    } else {
      return base.object()->Get(ctx_, s, e);
    }
  }

  JSVal LoadPropPrimitive(JSVal base,
                          Symbol s, bool strict, Error* e) {
    JSVal res;
    if (GetPrimitiveOwnProperty(base, s, &res)) {
      return res;
    }
    // if base is primitive, property not found in "this" object
    // so, lookup from proto
    Slot slot;
    JSObject* const proto = base.GetPrimitiveProto(ctx_);
    if (proto->GetPropertySlot(ctx_, s, &slot)) {
      return slot.Get(ctx_, base, e);
    } else {
      return JSUndefined;
    }
  }

#undef CHECK

#define CHECK IV_LV5_ERROR_VOID(e)

  void StoreName(JSEnv* env, Symbol name,
                 JSVal stored, bool strict, Error* e) {
    if (JSEnv* current = GetEnv(env, name)) {
      current->SetMutableBinding(ctx_, name, stored, strict, e);
    } else {
      if (strict) {
        e->Report(Error::Reference,
                  "putting to unresolvable reference "
                  "not allowed in strict reference");
      } else {
        ctx_->global_obj()->Put(ctx_, name, stored, strict, e);
      }
    }
  }

  void StoreHeap(JSEnv* env, Symbol name,
                 JSVal stored, bool strict,
                 uint32_t offset, uint32_t scope_nest_count, Error* e) {
    GetHeapEnv(env, scope_nest_count)->SetByOffset(offset, stored, strict, e);
  }

  void StoreElement(JSVal base, JSVal element,
                    JSVal stored, bool strict, Error* e) {
    base.CheckObjectCoercible(CHECK);
    const Symbol s = element.ToSymbol(ctx_, CHECK);
    StorePropImpl(base, s, stored, strict, e);
  }

  void StoreProp(JSVal base, Symbol s,
                 JSVal stored, bool strict, Error* e) {
    base.CheckObjectCoercible(CHECK);
    StorePropImpl(base, s, stored, strict, e);
  }

  void StoreProp(JSVal base,
                 Instruction* instr,
                 OP::Type generic,
                 Symbol name, JSVal src, bool strict, Error* e) {
    // opcode | (base | src | index) | nop | nop
    base.CheckObjectCoercible(CHECK);
    if (base.IsPrimitive()) {
      StorePropPrimitive(base, name, src, strict, e);
      return;
    }

    // cache patten
    JSObject* obj = base.object();
    if (instr[2].map == obj->map()) {
      // map is cached, so use previous index code
      obj->Direct(instr[3].u32[0]) = src;
      return;
    }

    Map* previous = obj->map();
    Slot slot;
    obj->PutSlot(ctx(), name, src, &slot, strict, CHECK);
    const Slot::PutResultType put_result_type = slot.put_result_type();
    const bool unique = previous->IsUnique() || obj->map()->IsUnique();

    // uncacheable pattern
    if (!slot.IsPutCacheable() || !symbol::IsArrayIndexSymbol(name)) {
      return;
    }

    assert(put_result_type != Slot::PUT_NONE);

    // TODO(Constellation) VM only store replace pattern.
    if (put_result_type == Slot::PUT_REPLACE) {
      if (previous == obj->map()) {
        instr[2].map = obj->map();
        instr[3].u32[0] = slot.offset();
      }
    }

    return;
  }

  void StorePropImpl(JSVal base, Symbol s,
                     JSVal stored, bool strict, Error* e) {
    if (base.IsPrimitive()) {
      StorePropPrimitive(base, s, stored, strict, e);
    } else {
      base.object()->Put(ctx_, s, stored, strict, e);
    }
  }

  void StorePropPrimitive(JSVal base, Symbol s,
                          JSVal stored, bool strict, Error* e) {
    assert(base.IsPrimitive());
    Slot slot;
    JSObject* const o = base.ToObject(ctx_, CHECK);
    if (!o->CanPut(ctx_, s, &slot)) {
      if (strict) {
        e->Report(Error::Type, "cannot put value to object");
      }
      return;
    }

    if (slot.IsNotFound() || slot.attributes().IsData()) {
      if (strict) {
        e->Report(Error::Type, "value to symbol in transient object");
      }
      return;
    }

    const Accessor* ac = slot.accessor();
    assert(ac->setter());
    ScopedArguments args(ctx_, 1, IV_LV5_ERROR_VOID(e));
    args[0] = stored;
    static_cast<JSFunction*>(ac->setter())->Call(&args, base, e);
  }
#undef CHECK

#define CHECK IV_LV5_ERROR_WITH(e, JSEmpty)

  JSVal BinaryAdd(JSVal lhs, JSVal rhs, Error* e) const {
    if (lhs.IsNumber() && rhs.IsNumber()) {
      return lhs.number() + rhs.number();
    }
    if (lhs.IsString()) {
      if (rhs.IsString()) {
        return JSString::New(ctx_, lhs.string(), rhs.string(), e);
      } else {
        const JSVal rp = rhs.ToPrimitive(ctx_, Hint::NONE, CHECK);
        JSString* const rs = rp.ToString(ctx_, CHECK);
        return JSString::New(ctx_, lhs.string(), rs, e);
      }
    }

    const JSVal lprim = lhs.ToPrimitive(ctx_, Hint::NONE, CHECK);
    const JSVal rprim = rhs.ToPrimitive(ctx_, Hint::NONE, CHECK);
    if (lprim.IsString() || rprim.IsString()) {
      JSString* const lstr = lprim.ToString(ctx_, CHECK);
      JSString* const rstr = rprim.ToString(ctx_, CHECK);
      return JSString::New(ctx_, lstr, rstr, e);
    }

    const double left = lprim.ToNumber(ctx_, CHECK);
    return left + rprim.ToNumber(ctx_, e);
  }

  JSVal BinarySub(JSVal lhs, JSVal rhs, Error* e) const {
    const double left = lhs.ToNumber(ctx_, CHECK);
    return left -  rhs.ToNumber(ctx_, e);
  }

  JSVal BinaryMultiply(JSVal lhs, JSVal rhs, Error* e) const {
    const double left = lhs.ToNumber(ctx_, CHECK);
    return left * rhs.ToNumber(ctx_, e);
  }

  JSVal BinaryDivide(JSVal lhs, JSVal rhs, Error* e) const {
    const double left = lhs.ToNumber(ctx_, CHECK);
    return left / rhs.ToNumber(ctx_, e);
  }

  JSVal BinaryModulo(JSVal lhs, JSVal rhs, Error* e) const {
    const double left = lhs.ToNumber(ctx_, CHECK);
    return core::math::Modulo(left, rhs.ToNumber(ctx_, e));
  }

  JSVal BinaryLShift(JSVal lhs, JSVal rhs, Error* e) const {
    const int32_t left = lhs.ToInt32(ctx_, CHECK);
    return JSVal::Int32(left << (rhs.ToInt32(ctx_, e) & 0x1f));
  }

  JSVal BinaryRShift(JSVal lhs, JSVal rhs, Error* e) const {
    const int32_t left = lhs.ToInt32(ctx_, CHECK);
    return JSVal::Int32(left >> (rhs.ToInt32(ctx_, e) & 0x1f));
  }

  JSVal BinaryRShiftLogical(JSVal lhs,
                            JSVal rhs, Error* e) const {
    const uint32_t left = lhs.ToUInt32(ctx_, CHECK);
    return JSVal::UInt32(left >> (rhs.ToInt32(ctx_, e) & 0x1f));
  }

  bool BinaryCompareLT(JSVal lhs,
                       JSVal rhs, Error* e) const {
    return JSVal::Compare<true>(ctx_, lhs, rhs, e) == CMP_TRUE;
  }

  bool BinaryCompareLTE(JSVal lhs,
                        JSVal rhs, Error* e) const {
    return JSVal::Compare<false>(ctx_, rhs, lhs, e) == CMP_FALSE;
  }

  bool BinaryCompareGT(JSVal lhs,
                       JSVal rhs, Error* e) const {
    return JSVal::Compare<false>(ctx_, rhs, lhs, e) == CMP_TRUE;
  }

  bool BinaryCompareGTE(JSVal lhs,
                        JSVal rhs, Error* e) const {
    return JSVal::Compare<true>(ctx_, lhs, rhs, e) == CMP_FALSE;
  }

  bool BinaryInstanceof(JSVal lhs,
                        JSVal rhs, Error* e) const {
    if (!rhs.IsObject()) {
      e->Report(Error::Type, "instanceof requires object");
      return false;
    }
    JSObject* const robj = rhs.object();
    if (!robj->IsCallable()) {
      e->Report(Error::Type, "instanceof requires constructor");
      return false;
    }
    return static_cast<JSFunction*>(robj)->HasInstance(ctx_, lhs, e);
  }

  bool BinaryIn(JSVal lhs,
                JSVal rhs, Error* e) const {
    if (!rhs.IsObject()) {
      e->Report(Error::Type, "in requires object");
      return false;
    }
    const Symbol s = lhs.ToSymbol(ctx_, IV_LV5_ERROR_WITH(e, false));
    return rhs.object()->HasProperty(ctx_, s);
  }

  bool BinaryEqual(JSVal lhs,
                   JSVal rhs, Error* e) const {
    return JSVal::AbstractEqual(ctx_, lhs, rhs, e);
  }

  bool BinaryStrictEqual(JSVal lhs,
                         JSVal rhs) const {
    return JSVal::StrictEqual(lhs, rhs);
  }

  bool BinaryNotEqual(JSVal lhs,
                      JSVal rhs, Error* e) const {
    return !JSVal::AbstractEqual(ctx_, lhs, rhs, e);
  }

  bool BinaryStrictNotEqual(JSVal lhs,
                            JSVal rhs) const {
    return !JSVal::StrictEqual(lhs, rhs);
  }

  int32_t BinaryBitAnd(JSVal lhs,
                       JSVal rhs, Error* e) const {
    const int32_t left = lhs.ToInt32(ctx_, IV_LV5_ERROR_WITH(e, 0));
    return left & rhs.ToInt32(ctx_, e);
  }

  int32_t BinaryBitXor(JSVal lhs,
                       JSVal rhs, Error* e) const {
    const int32_t left = lhs.ToInt32(ctx_, IV_LV5_ERROR_WITH(e, 0));
    return left ^ rhs.ToInt32(ctx_, e);
  }

  int32_t BinaryBitOr(JSVal lhs,
                      JSVal rhs, Error* e) const {
    const int32_t left = lhs.ToInt32(ctx_, IV_LV5_ERROR_WITH(e, 0));
    return left | rhs.ToInt32(ctx_, e);
  }

  template<int Target, std::size_t Returned>
  JSVal IncrementName(JSEnv* env, Symbol s, bool strict, Error* e) {
    if (JSEnv* current = GetEnv(env, s)) {
      const JSVal w = current->GetBindingValue(ctx_, s, strict, CHECK);
      if (w.IsInt32() && detail::IsIncrementOverflowSafe<Target>(w.int32())) {
        std::tuple<JSVal, JSVal> results;
        const int32_t target = w.int32();
        std::get<0>(results) = w;
        std::get<1>(results) = JSVal::Int32(target + Target);
        current->SetMutableBinding(
            ctx_, s,
            std::get<1>(results), strict, e);
        return std::get<Returned>(results);
      } else {
        std::tuple<double, double> results;
        std::get<0>(results) = w.ToNumber(ctx_, CHECK);
        std::get<1>(results) = std::get<0>(results) + Target;
        current->SetMutableBinding(ctx_, s,
                                   std::get<1>(results), strict, e);
        return std::get<Returned>(results);
      }
    }
    RaiseReferenceError(s, e);
    return 0.0;
  }

  template<int Target, std::size_t Returned>
  JSVal IncrementHeap(JSEnv* env, Symbol s,
                      bool strict, uint32_t offset,
                      uint32_t scope_nest_count, Error* e) {
    JSDeclEnv* decl = GetHeapEnv(env, scope_nest_count);
    const JSVal w = decl->GetByOffset(offset, strict, CHECK);
    if (w.IsInt32() && detail::IsIncrementOverflowSafe<Target>(w.int32())) {
      std::tuple<JSVal, JSVal> results;
      const int32_t target = w.int32();
      std::get<0>(results) = w;
      std::get<1>(results) = JSVal::Int32(target + Target);
      decl->SetByOffset(offset, std::get<1>(results), strict, e);
      return std::get<Returned>(results);
    } else {
      std::tuple<double, double> results;
      std::get<0>(results) = w.ToNumber(ctx_, CHECK);
      std::get<1>(results) = std::get<0>(results) + Target;
      decl->SetByOffset(offset, std::get<1>(results), strict, e);
      return std::get<Returned>(results);
    }
  }

  template<int Target, std::size_t Returned>
  JSVal IncrementElement(JSVal base,
                         JSVal element, bool strict, Error* e) {
    base.CheckObjectCoercible(CHECK);
    const Symbol s = element.ToSymbol(ctx_, CHECK);
    const JSVal w = LoadPropImpl(base, s, strict, CHECK);
    if (w.IsInt32() && detail::IsIncrementOverflowSafe<Target>(w.int32())) {
      std::tuple<JSVal, JSVal> results;
      const int32_t target = w.int32();
      std::get<0>(results) = w;
      std::get<1>(results) = JSVal::Int32(target + Target);
      StorePropImpl(base, s, std::get<1>(results), strict, e);
      return std::get<Returned>(results);
    } else {
      std::tuple<double, double> results;
      std::get<0>(results) = w.ToNumber(ctx_, CHECK);
      std::get<1>(results) = std::get<0>(results) + Target;
      StorePropImpl(base, s, std::get<1>(results), strict, e);
      return std::get<Returned>(results);
    }
  }

  template<int Target, std::size_t Returned>
  JSVal IncrementProp(JSVal base,
                      Symbol s, bool strict, Error* e) {
    base.CheckObjectCoercible(CHECK);
    const JSVal w = LoadPropImpl(base, s, strict, CHECK);
    if (w.IsInt32() && detail::IsIncrementOverflowSafe<Target>(w.int32())) {
      std::tuple<JSVal, JSVal> results;
      const int32_t target = w.int32();
      std::get<0>(results) = w;
      std::get<1>(results) = JSVal::Int32(target + Target);
      StorePropImpl(base, s, std::get<1>(results), strict, e);
      return std::get<Returned>(results);
    } else {
      std::tuple<double, double> results;
      std::get<0>(results) = w.ToNumber(ctx_, CHECK);
      std::get<1>(results) = std::get<0>(results) + Target;
      StorePropImpl(base, s, std::get<1>(results), strict, e);
      return std::get<Returned>(results);
    }
  }

  JSVal LoadGlobal(JSGlobal* global,
                   Instruction* instr, const Symbol& s, bool strict, Error* e) {
    // opcode | (dst | index) | nop | nop
    if (instr[2].map == global->map()) {
      // map is cached, so use previous index code
      return global->Direct(instr[3].u32[0]);
    } else {
      // now Own Property Pattern only implemented
      Slot slot;
      assert(!symbol::IsArrayIndexSymbol(s));
      if (global->GetOwnPropertySlot(ctx_, s, &slot)) {
        if (slot.IsLoadCacheable()) {
          instr[2].map = global->map();
          instr[3].u32[0] = slot.offset();
          return slot.value();
        }
        return slot.Get(ctx_, global, e);
      } else {
        instr[2].map = NULL;
        return LoadName(ctx_->global_env(), s, strict, e);
      }
    }
  }

  bool GetPrimitiveOwnProperty(JSVal base, const Symbol& s, JSVal* res) {
    // section 8.7.1 special [[Get]]
    assert(base.IsPrimitive());
    if (base.IsString()) {
      // string short circuit
      JSString* str = base.string();
      if (s == symbol::length()) {
        *res = JSVal::UInt32(static_cast<uint32_t>(str->size()));
        return true;
      }
      if (symbol::IsArrayIndexSymbol(s)) {
        const uint32_t index = symbol::GetIndexFromSymbol(s);
        if (index < str->size()) {
          *res = JSString::NewSingle(ctx_, str->At(index));
          return true;
        }
      }
    }
    return false;
  }

#undef CHECK

  inline lv5::Context* ctx() const { return ctx_; }
 private:
  lv5::Context* ctx_;
};


} } }  // namespace iv::lv5::railgun
#endif  // IV_LV5_RAILGUN_OPERATION_H_