codegen-arm.cc.svn-base

Google浏览器V8内核代码

    __ push(r0);
    __ bind(&loaded);
    cc_reg_ = al;
  }

  if (true_target.is_linked() || false_target.is_linked()) {
    // we have at least one condition value
    // that has been "translated" into a branch,
    // thus it needs to be loaded explicitly again
    Label loaded;
    __ b(&loaded);  // don't lose current TOS
    bool both = true_target.is_linked() && false_target.is_linked();
    // reincarnate "true", if necessary
    if (true_target.is_linked()) {
      __ bind(&true_target);
      __ mov(r0, Operand(Factory::true_value()));
      __ push(r0);
    }
    // if both "true" and "false" need to be reincarnated,
    // jump across code for "false"
    if (both)
      __ b(&loaded);
    // reincarnate "false", if necessary
    if (false_target.is_linked()) {
      __ bind(&false_target);
      __ mov(r0, Operand(Factory::false_value()));
      __ push(r0);
    }
    // everything is loaded at this point
    __ bind(&loaded);
  }
  ASSERT(!has_cc());
}


void ArmCodeGenerator::LoadGlobal() {
  __ ldr(r0, GlobalObject());
  __ push(r0);
}


// TODO(1241834): Get rid of this function in favor of just using Load, now
// that we have the LOAD_TYPEOF_EXPR access type. => Need to handle
// global variables w/o reference errors elsewhere.
void ArmCodeGenerator::LoadTypeofExpression(Expression* x) {
  Variable* variable = x->AsVariableProxy()->AsVariable();
  if (variable != NULL && !variable->is_this() && variable->is_global()) {
    // NOTE: This is somewhat nasty. We force the compiler to load
    // the variable as if through '<global>.<variable>' to make sure we
    // do not get reference errors.
    Slot global(variable, Slot::CONTEXT, Context::GLOBAL_INDEX);
    Literal key(variable->name());
    // TODO(1241834): Fetch the position from the variable instead of using
    // no position.
    Property property(&global, &key, RelocInfo::kNoPosition);
    Load(&property);
  } else {
    Load(x, CodeGenState::LOAD_TYPEOF_EXPR);
  }
}


Reference::Reference(ArmCodeGenerator* cgen, Expression* expression)
    : cgen_(cgen), expression_(expression), type_(ILLEGAL) {
  cgen->LoadReference(this);
}


Reference::~Reference() {
  cgen_->UnloadReference(this);
}


void ArmCodeGenerator::LoadReference(Reference* ref) {
  Expression* e = ref->expression();
  Property* property = e->AsProperty();
  Variable* var = e->AsVariableProxy()->AsVariable();

  if (property != NULL) {
    Load(property->obj());
    // Used a named reference if the key is a literal symbol.
    // We don't use a named reference if they key is a string that can be
    // legally parsed as an integer.  This is because, otherwise we don't
    // get into the slow case code that handles [] on String objects.
    Literal* literal = property->key()->AsLiteral();
    uint32_t dummy;
    if (literal != NULL && literal->handle()->IsSymbol() &&
      !String::cast(*(literal->handle()))->AsArrayIndex(&dummy)) {
      ref->set_type(Reference::NAMED);
    } else {
      Load(property->key());
      ref->set_type(Reference::KEYED);
    }
  } else if (var != NULL) {
    if (var->is_global()) {
      // global variable
      LoadGlobal();
      ref->set_type(Reference::NAMED);
    } else {
      // local variable
      ref->set_type(Reference::EMPTY);
    }
  } else {
    Load(e);
    __ CallRuntime(Runtime::kThrowReferenceError, 1);
    __ push(r0);
  }
}


void ArmCodeGenerator::UnloadReference(Reference* ref) {
  int size = ref->size();
  if (size <= 0) {
    // Do nothing. No popping is necessary.
  } else {
    __ pop(r0);
    __ add(sp, sp, Operand(size * kPointerSize));
    __ push(r0);
  }
}


void Property::GenerateStoreCode(MacroAssembler* masm,
                                 Scope* scope,
                                 Reference* ref,
                                 InitState init_state) {
  Comment cmnt(masm, "[ Store to Property");
  masm->RecordPosition(position());
  ArmCodeGenerator::SetReferenceProperty(masm, ref, key());
}


void VariableProxy::GenerateStoreCode(MacroAssembler* masm,
                                      Scope* scope,
                                      Reference* ref,
                                      InitState init_state) {
  Comment cmnt(masm, "[ Store to VariableProxy");
  Variable* node = var();

  Expression* expr = node->rewrite();
  if (expr != NULL) {
    expr->GenerateStoreCode(masm, scope, ref, init_state);
  } else {
    ASSERT(node->is_global());
    if (node->AsProperty() != NULL) {
      masm->RecordPosition(node->AsProperty()->position());
    }
    ArmCodeGenerator::SetReferenceProperty(masm, ref,
                                           new Literal(node->name()));
  }
}


void Slot::GenerateStoreCode(MacroAssembler* masm,
                             Scope* scope,
                             Reference* ref,
                             InitState init_state) {
  Comment cmnt(masm, "[ Store to Slot");

  if (type() == Slot::LOOKUP) {
    ASSERT(var()->mode() == Variable::DYNAMIC);

    // For now, just do a runtime call.
    masm->push(cp);
    masm->mov(r0, Operand(var()->name()));
    masm->push(r0);

    if (init_state == CONST_INIT) {
      // Same as the case for a normal store, but ignores attribute
      // (e.g. READ_ONLY) of context slot so that we can initialize const
      // properties (introduced via eval("const foo = (some expr);")). Also,
      // uses the current function context instead of the top context.
      //
      // Note that we must declare the foo upon entry of eval(), via a
      // context slot declaration, but we cannot initialize it at the same
      // time, because the const declaration may be at the end of the eval
      // code (sigh...) and the const variable may have been used before
      // (where its value is 'undefined'). Thus, we can only do the
      // initialization when we actually encounter the expression and when
      // the expression operands are defined and valid, and thus we need the
      // split into 2 operations: declaration of the context slot followed
      // by initialization.
      masm->CallRuntime(Runtime::kInitializeConstContextSlot, 3);
    } else {
      masm->CallRuntime(Runtime::kStoreContextSlot, 3);
    }
    // Storing a variable must keep the (new) value on the expression
    // stack. This is necessary for compiling assignment expressions.
    masm->push(r0);

  } else {
    ASSERT(var()->mode() != Variable::DYNAMIC);

    Label exit;
    if (init_state == CONST_INIT) {
      ASSERT(var()->mode() == Variable::CONST);
      // Only the first const initialization must be executed (the slot
      // still contains 'the hole' value). When the assignment is executed,
      // the code is identical to a normal store (see below).
      Comment cmnt(masm, "[ Init const");
      masm->ldr(r2, ArmCodeGenerator::SlotOperand(masm, scope, this, r2));
      masm->cmp(r2, Operand(Factory::the_hole_value()));
      masm->b(ne, &exit);
    }

    // We must execute the store.
    // r2 may be loaded with context; used below in RecordWrite.
    // Storing a variable must keep the (new) value on the stack. This is
    // necessary for compiling assignment expressions.
    //
    // Note: We will reach here even with var()->mode() == Variable::CONST
    // because of const declarations which will initialize consts to 'the
    // hole' value and by doing so, end up calling this code.  r2 may be
    // loaded with context; used below in RecordWrite.
    masm->pop(r0);
    masm->str(r0, ArmCodeGenerator::SlotOperand(masm, scope, this, r2));
    masm->push(r0);

    if (type() == Slot::CONTEXT) {
      // Skip write barrier if the written value is a smi.
      masm->tst(r0, Operand(kSmiTagMask));
      masm->b(eq, &exit);
      // r2 is loaded with context when calling SlotOperand above.
      int offset = FixedArray::kHeaderSize + index() * kPointerSize;
      masm->mov(r3, Operand(offset));
      masm->RecordWrite(r2, r3, r1);
    }
    // If we definitely did not jump over the assignment, we do not need to
    // bind the exit label.  Doing so can defeat peephole optimization.
    if (init_state == CONST_INIT || type() == Slot::CONTEXT) {
      masm->bind(&exit);
    }
  }
}


// ECMA-262, section 9.2, page 30: ToBoolean(). Convert the given
// register to a boolean in the condition code register. The code
// may jump to 'false_target' in case the register converts to 'false'.
void ArmCodeGenerator::ToBoolean(Label* true_target,
                                 Label* false_target) {
  // Note: The generated code snippet does not change stack variables.
  //       Only the condition code should be set.
  __ pop(r0);

  // Fast case checks

  // Check if the value is 'false'.
  __ cmp(r0, Operand(Factory::false_value()));
  __ b(eq, false_target);

  // Check if the value is 'true'.
  __ cmp(r0, Operand(Factory::true_value()));
  __ b(eq, true_target);

  // Check if the value is 'undefined'.
  __ cmp(r0, Operand(Factory::undefined_value()));
  __ b(eq, false_target);

  // Check if the value is a smi.
  __ cmp(r0, Operand(Smi::FromInt(0)));
  __ b(eq, false_target);
  __ tst(r0, Operand(kSmiTagMask));
  __ b(eq, true_target);

  // Slow case: call the runtime.
  __ push(r0);
  __ CallRuntime(Runtime::kToBool, 1);

  // Convert result (r0) to condition code
  __ cmp(r0, Operand(Factory::false_value()));

  cc_reg_ = ne;
}


#undef __
#define __  masm->


class GetPropertyStub : public CodeStub {
 public:
  GetPropertyStub() { }

 private:
  Major MajorKey() { return GetProperty; }
  int MinorKey() { return 0; }
  void Generate(MacroAssembler* masm);

  const char* GetName() { return "GetPropertyStub"; }
};


void GetPropertyStub::Generate(MacroAssembler* masm) {
  // sp[0]: key
  // sp[1]: receiver
  Label slow, fast;
  // Get the key and receiver object from the stack.
  __ ldm(ia, sp, r0.bit() | r1.bit());
  // Check that the key is a smi.
  __ tst(r0, Operand(kSmiTagMask));
  __ b(ne, &slow);
  __ mov(r0, Operand(r0, ASR, kSmiTagSize));
  // Check that the object isn't a smi.
  __ tst(r1, Operand(kSmiTagMask));
  __ b(eq, &slow);

  // Check that the object is some kind of JS object EXCEPT JS Value type.
  // In the case that the object is a value-wrapper object,
  // we enter the runtime system to make sure that indexing into string
  // objects work as intended.
  ASSERT(JS_OBJECT_TYPE > JS_VALUE_TYPE);
  __ ldr(r2, FieldMemOperand(r1, HeapObject::kMapOffset));
  __ ldrb(r2, FieldMemOperand(r2, Map::kInstanceTypeOffset));
  __ cmp(r2, Operand(JS_OBJECT_TYPE));
  __ b(lt, &slow);

  // Get the elements array of the object.
  __ ldr(r1, FieldMemOperand(r1, JSObject::kElementsOffset));
  // Check that the object is in fast mode (not dictionary).
  __ ldr(r3, FieldMemOperand(r1, HeapObject::kMapOffset));
  __ cmp(r3, Operand(Factory::hash_table_map()));
  __ b(eq, &slow);
  // Check that the key (index) is within bounds.
  __ ldr(r3, FieldMemOperand(r1, Array::kLengthOffset));
  __ cmp(r0, Operand(r3));
  __ b(lo, &fast);

  // Slow case: Push extra copies of the arguments (2).
  __ bind(&slow);
  __ ldm(ia, sp, r0.bit() | r1.bit());
  __ stm(db_w, sp, r0.bit() | r1.bit());
  // Do tail-call to runtime routine.
  __ TailCallRuntime(ExternalReference(Runtime::kGetProperty), 2);

  // Fast case: Do the load.
  __ bind(&fast);
  __ add(r3, r1, Operand(Array::kHeaderSize - kHeapObjectTag));
  __ ldr(r0, MemOperand(r3, r0, LSL, kPointerSizeLog2));
  __ cmp(r0, Operand(Factory::the_hole_value()));
  // In case the loaded value is the_hole we have to consult GetProperty
  // to ensure the prototype chain is searched.
  __ b(eq, &slow);

  masm->StubReturn(1);
}


class SetPropertyStub : public CodeStub {
 public:
  SetPropertyStub() { }

 private:
  Major MajorKey() { return SetProperty; }
  int MinorKey() { return 0; }
  void Generate(MacroAssembler* masm);

  const char* GetName() { return "GetPropertyStub"; }
};



void SetPropertyStub::Generate(MacroAssembler* masm) {
  // r0 : value
  // sp[0] : key
  // sp[1] : receiver

  Label slow, fast, array, extra, exit;
  // Get the key and the object from the stack.
  __ ldm(ia, sp, r1.bit() | r3.bit());  // r1 = key, r3 = receiver
  // Check that the key is a smi.
  __ tst(r1, Operand(kSmiTagMask));
  __ b(ne, &slow);
  // Check that the object isn't a smi.
  __ tst(r3, Operand(kSmiTagMask));
  __ b(eq, &slow);
  // Get the type of the object from its map.
  __ ldr(r2, FieldMemOperand(r3, HeapObject::kMapOffset));
  __ ldrb(r2, FieldMemOperand(r2, Map::kInstanceTypeOffset));
  // Check if the object is a JS array or not.
  __ cmp(r2, Operand(JS_ARRAY_TYPE));
  __ b(eq, &array);
  // Check that the object is some kind of JS object.
  __ cmp(r2, Operand(FIRST_JS_OBJECT_TYPE));
  __ b(lt, &slow);