codegen-arm.cc.svn-base

Google浏览器V8内核代码

  // Object case: Check key against length in the elements array.
  __ ldr(r3, FieldMemOperand(r3, JSObject::kElementsOffset));
  // Check that the object is in fast mode (not dictionary).
  __ ldr(r2, FieldMemOperand(r3, HeapObject::kMapOffset));
  __ cmp(r2, Operand(Factory::hash_table_map()));
  __ b(eq, &slow);
  // Untag the key (for checking against untagged length in the fixed array).
  __ mov(r1, Operand(r1, ASR, kSmiTagSize));
  // Compute address to store into and check array bounds.
  __ add(r2, r3, Operand(Array::kHeaderSize - kHeapObjectTag));
  __ add(r2, r2, Operand(r1, LSL, kPointerSizeLog2));
  __ ldr(ip, FieldMemOperand(r3, Array::kLengthOffset));
  __ cmp(r1, Operand(ip));
  __ b(lo, &fast);


  // Slow case: Push extra copies of the arguments (3).
  __ bind(&slow);
  __ ldm(ia, sp, r1.bit() | r3.bit());  // r0 == value, r1 == key, r3 == object
  __ stm(db_w, sp, r0.bit() | r1.bit() | r3.bit());
  // Do tail-call to runtime routine.
  __ TailCallRuntime(ExternalReference(Runtime::kSetProperty), 3);


  // Extra capacity case: Check if there is extra capacity to
  // perform the store and update the length. Used for adding one
  // element to the array by writing to array[array.length].
  // r0 == value, r1 == key, r2 == elements, r3 == object
  __ bind(&extra);
  __ b(ne, &slow);  // do not leave holes in the array
  __ mov(r1, Operand(r1, ASR, kSmiTagSize));  // untag
  __ ldr(ip, FieldMemOperand(r2, Array::kLengthOffset));
  __ cmp(r1, Operand(ip));
  __ b(hs, &slow);
  __ mov(r1, Operand(r1, LSL, kSmiTagSize));  // restore tag
  __ add(r1, r1, Operand(1 << kSmiTagSize));  // and increment
  __ str(r1, FieldMemOperand(r3, JSArray::kLengthOffset));
  __ mov(r3, Operand(r2));
  // NOTE: Computing the address to store into must take the fact
  // that the key has been incremented into account.
  int displacement = Array::kHeaderSize - kHeapObjectTag -
      ((1 << kSmiTagSize) * 2);
  __ add(r2, r2, Operand(displacement));
  __ add(r2, r2, Operand(r1, LSL, kPointerSizeLog2 - kSmiTagSize));
  __ b(&fast);


  // Array case: Get the length and the elements array from the JS
  // array. Check that the array is in fast mode; if it is the
  // length is always a smi.
  // r0 == value, r3 == object
  __ bind(&array);
  __ ldr(r2, FieldMemOperand(r3, JSObject::kElementsOffset));
  __ ldr(r1, FieldMemOperand(r2, HeapObject::kMapOffset));
  __ cmp(r1, Operand(Factory::hash_table_map()));
  __ b(eq, &slow);

  // Check the key against the length in the array, compute the
  // address to store into and fall through to fast case.
  __ ldr(r1, MemOperand(sp));
  // r0 == value, r1 == key, r2 == elements, r3 == object.
  __ ldr(ip, FieldMemOperand(r3, JSArray::kLengthOffset));
  __ cmp(r1, Operand(ip));
  __ b(hs, &extra);
  __ mov(r3, Operand(r2));
  __ add(r2, r2, Operand(Array::kHeaderSize - kHeapObjectTag));
  __ add(r2, r2, Operand(r1, LSL, kPointerSizeLog2 - kSmiTagSize));


  // Fast case: Do the store.
  // r0 == value, r2 == address to store into, r3 == elements
  __ bind(&fast);
  __ str(r0, MemOperand(r2));
  // Skip write barrier if the written value is a smi.
  __ tst(r0, Operand(kSmiTagMask));
  __ b(eq, &exit);
  // Update write barrier for the elements array address.
  __ sub(r1, r2, Operand(r3));
  __ RecordWrite(r3, r1, r2);
  __ bind(&exit);
  masm->StubReturn(1);
}


class GenericBinaryOpStub : public CodeStub {
 public:
  explicit GenericBinaryOpStub(Token::Value op) : op_(op) { }

 private:
  Token::Value op_;

  Major MajorKey() { return GenericBinaryOp; }
  int MinorKey() { return static_cast<int>(op_); }
  void Generate(MacroAssembler* masm);

  const char* GetName() {
    switch (op_) {
      case Token::ADD: return "GenericBinaryOpStub_ADD";
      case Token::SUB: return "GenericBinaryOpStub_SUB";
      case Token::MUL: return "GenericBinaryOpStub_MUL";
      case Token::DIV: return "GenericBinaryOpStub_DIV";
      case Token::BIT_OR: return "GenericBinaryOpStub_BIT_OR";
      case Token::BIT_AND: return "GenericBinaryOpStub_BIT_AND";
      case Token::BIT_XOR: return "GenericBinaryOpStub_BIT_XOR";
      case Token::SAR: return "GenericBinaryOpStub_SAR";
      case Token::SHL: return "GenericBinaryOpStub_SHL";
      case Token::SHR: return "GenericBinaryOpStub_SHR";
      default:         return "GenericBinaryOpStub";
    }
  }

#ifdef DEBUG
  void Print() { PrintF("GenericBinaryOpStub (%s)\n", Token::String(op_)); }
#endif
};


void GenericBinaryOpStub::Generate(MacroAssembler* masm) {
  // r1 : x
  // r0 : y
  // result : r0

  switch (op_) {
    case Token::ADD: {
      Label slow, exit;
      // fast path
      __ orr(r2, r1, Operand(r0));  // r2 = x | y;
      __ add(r0, r1, Operand(r0), SetCC);  // add y optimistically
      // go slow-path in case of overflow
      __ b(vs, &slow);
      // go slow-path in case of non-smi operands
      ASSERT(kSmiTag == 0);  // adjust code below
      __ tst(r2, Operand(kSmiTagMask));
      __ b(eq, &exit);
      // slow path
      __ bind(&slow);
      __ sub(r0, r0, Operand(r1));  // revert optimistic add
      __ push(r1);
      __ push(r0);
      __ mov(r0, Operand(1));  // set number of arguments
      __ InvokeBuiltin(Builtins::ADD, JUMP_JS);
      // done
      __ bind(&exit);
      break;
    }

    case Token::SUB: {
      Label slow, exit;
      // fast path
      __ orr(r2, r1, Operand(r0));  // r2 = x | y;
      __ sub(r3, r1, Operand(r0), SetCC);  // subtract y optimistically
      // go slow-path in case of overflow
      __ b(vs, &slow);
      // go slow-path in case of non-smi operands
      ASSERT(kSmiTag == 0);  // adjust code below
      __ tst(r2, Operand(kSmiTagMask));
      __ mov(r0, Operand(r3), LeaveCC, eq);  // conditionally set r0 to result
      __ b(eq, &exit);
      // slow path
      __ bind(&slow);
      __ push(r1);
      __ push(r0);
      __ mov(r0, Operand(1));  // set number of arguments
      __ InvokeBuiltin(Builtins::SUB, JUMP_JS);
      // done
      __ bind(&exit);
      break;
    }

    case Token::MUL: {
      Label slow, exit;
      // tag check
      __ orr(r2, r1, Operand(r0));  // r2 = x | y;
      ASSERT(kSmiTag == 0);  // adjust code below
      __ tst(r2, Operand(kSmiTagMask));
      __ b(ne, &slow);
      // remove tag from one operand (but keep sign), so that result is smi
      __ mov(ip, Operand(r0, ASR, kSmiTagSize));
      // do multiplication
      __ smull(r3, r2, r1, ip);  // r3 = lower 32 bits of ip*r1
      // go slow on overflows (overflow bit is not set)
      __ mov(ip, Operand(r3, ASR, 31));
      __ cmp(ip, Operand(r2));  // no overflow if higher 33 bits are identical
      __ b(ne, &slow);
      // go slow on zero result to handle -0
      __ tst(r3, Operand(r3));
      __ mov(r0, Operand(r3), LeaveCC, ne);
      __ b(ne, &exit);
      // slow case
      __ bind(&slow);
      __ push(r1);
      __ push(r0);
      __ mov(r0, Operand(1));  // set number of arguments
      __ InvokeBuiltin(Builtins::MUL, JUMP_JS);
      // done
      __ bind(&exit);
      break;
    }

    case Token::BIT_OR:
    case Token::BIT_AND:
    case Token::BIT_XOR: {
      Label slow, exit;
      // tag check
      __ orr(r2, r1, Operand(r0));  // r2 = x | y;
      ASSERT(kSmiTag == 0);  // adjust code below
      __ tst(r2, Operand(kSmiTagMask));
      __ b(ne, &slow);
      switch (op_) {
        case Token::BIT_OR:  __ orr(r0, r0, Operand(r1)); break;
        case Token::BIT_AND: __ and_(r0, r0, Operand(r1)); break;
        case Token::BIT_XOR: __ eor(r0, r0, Operand(r1)); break;
        default: UNREACHABLE();
      }
      __ b(&exit);
      __ bind(&slow);
      __ push(r1);  // restore stack
      __ push(r0);
      __ mov(r0, Operand(1));  // 1 argument (not counting receiver).
      switch (op_) {
        case Token::BIT_OR:
          __ InvokeBuiltin(Builtins::BIT_OR, JUMP_JS);
          break;
        case Token::BIT_AND:
          __ InvokeBuiltin(Builtins::BIT_AND, JUMP_JS);
          break;
        case Token::BIT_XOR:
          __ InvokeBuiltin(Builtins::BIT_XOR, JUMP_JS);
          break;
        default:
          UNREACHABLE();
      }
      __ bind(&exit);
      break;
    }

    case Token::SHL:
    case Token::SHR:
    case Token::SAR: {
      Label slow, exit;
      // tag check
      __ orr(r2, r1, Operand(r0));  // r2 = x | y;
      ASSERT(kSmiTag == 0);  // adjust code below
      __ tst(r2, Operand(kSmiTagMask));
      __ b(ne, &slow);
      // remove tags from operands (but keep sign)
      __ mov(r3, Operand(r1, ASR, kSmiTagSize));  // x
      __ mov(r2, Operand(r0, ASR, kSmiTagSize));  // y
      // use only the 5 least significant bits of the shift count
      __ and_(r2, r2, Operand(0x1f));
      // perform operation
      switch (op_) {
        case Token::SAR:
          __ mov(r3, Operand(r3, ASR, r2));
          // no checks of result necessary
          break;

        case Token::SHR:
          __ mov(r3, Operand(r3, LSR, r2));
          // check that the *unsigned* result fits in a smi
          // neither of the two high-order bits can be set:
          // - 0x80000000: high bit would be lost when smi tagging
          // - 0x40000000: this number would convert to negative when
          // smi tagging these two cases can only happen with shifts
          // by 0 or 1 when handed a valid smi
          __ and_(r2, r3, Operand(0xc0000000), SetCC);
          __ b(ne, &slow);
          break;

        case Token::SHL:
          __ mov(r3, Operand(r3, LSL, r2));
          // check that the *signed* result fits in a smi
          __ add(r2, r3, Operand(0x40000000), SetCC);
          __ b(mi, &slow);
          break;

        default: UNREACHABLE();
      }
      // tag result and store it in r0
      ASSERT(kSmiTag == 0);  // adjust code below
      __ mov(r0, Operand(r3, LSL, kSmiTagSize));
      __ b(&exit);
      // slow case
      __ bind(&slow);
      __ push(r1);  // restore stack
      __ push(r0);
      __ mov(r0, Operand(1));  // 1 argument (not counting receiver).
      switch (op_) {
        case Token::SAR: __ InvokeBuiltin(Builtins::SAR, JUMP_JS); break;
        case Token::SHR: __ InvokeBuiltin(Builtins::SHR, JUMP_JS); break;
        case Token::SHL: __ InvokeBuiltin(Builtins::SHL, JUMP_JS); break;
        default: UNREACHABLE();
      }
      __ bind(&exit);
      break;
    }

    default: UNREACHABLE();
  }
  __ Ret();
}


void StackCheckStub::Generate(MacroAssembler* masm) {
  Label within_limit;
  __ mov(ip, Operand(ExternalReference::address_of_stack_guard_limit()));
  __ ldr(ip, MemOperand(ip));
  __ cmp(sp, Operand(ip));
  __ b(hs, &within_limit);
  // Do tail-call to runtime routine.
  __ push(r0);
  __ TailCallRuntime(ExternalReference(Runtime::kStackGuard), 1);
  __ bind(&within_limit);

  masm->StubReturn(1);
}


void UnarySubStub::Generate(MacroAssembler* masm) {
  Label undo;
  Label slow;
  Label done;

  // Enter runtime system if the value is not a smi.
  __ tst(r0, Operand(kSmiTagMask));
  __ b(ne, &slow);

  // Enter runtime system if the value of the expression is zero
  // to make sure that we switch between 0 and -0.
  __ cmp(r0, Operand(0));
  __ b(eq, &slow);

  // The value of the expression is a smi that is not zero.  Try
  // optimistic subtraction '0 - value'.
  __ rsb(r1, r0, Operand(0), SetCC);
  __ b(vs, &slow);

  // If result is a smi we are done.
  __ tst(r1, Operand(kSmiTagMask));
  __ mov(r0, Operand(r1), LeaveCC, eq);  // conditionally set r0 to result
  __ b(eq, &done);

  // Enter runtime system.
  __ bind(&slow);
  __ push(r0);
  __ mov(r0, Operand(0));  // set number of arguments
  __ InvokeBuiltin(Builtins::UNARY_MINUS, JUMP_JS);

  __ bind(&done);
  masm->StubReturn(1);
}


class InvokeBuiltinStub : public CodeStub {
 public:
  enum Kind { Inc, Dec, ToNumber };
  InvokeBuiltinStub(Kind kind, int argc) : kind_(kind), argc_(argc) { }

 private:
  Kind kind_;
  int argc_;

  Major MajorKey() { return InvokeBuiltin; }
  int MinorKey() { return (argc_ << 3) | static_cast<int>(kind_); }
  void Generate(MacroAssembler* masm);

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

#ifdef DEBUG
  void Print() {
    PrintF("InvokeBuiltinStub (kind %d, argc, %d)\n",
           static_cast<int>(kind_),
           argc_);
  }
#endif
};


void InvokeBuiltinStub::Generate(MacroAssembler* masm) {
  __ push(r0);
  __ mov(r0, Operand(0));  // set number of arguments
  switch (kind_) {
    case ToNumber: __ InvokeBuiltin(Builtins::TO_NUMBER, JUMP_JS); break;
    case Inc:      __ InvokeBuiltin(Builtins::INC, JUMP_JS);       break;
    case Dec:      __ InvokeBuiltin(Builtins::DEC, JUMP_JS);       break;
    default: UNREACHABLE();
  }