| // Copyright 2009 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef V8_FRAME_ELEMENT_H_ |
| #define V8_FRAME_ELEMENT_H_ |
| |
| #include "number-info.h" |
| #include "macro-assembler.h" |
| #include "zone.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| // ------------------------------------------------------------------------- |
| // Virtual frame elements |
| // |
| // The internal elements of the virtual frames. There are several kinds of |
| // elements: |
| // * Invalid: elements that are uninitialized or not actually part |
| // of the virtual frame. They should not be read. |
| // * Memory: an element that resides in the actual frame. Its address is |
| // given by its position in the virtual frame. |
| // * Register: an element that resides in a register. |
| // * Constant: an element whose value is known at compile time. |
| |
| class FrameElement BASE_EMBEDDED { |
| public: |
| enum SyncFlag { |
| NOT_SYNCED, |
| SYNCED |
| }; |
| |
| inline NumberInfo number_info() { |
| // Copied elements do not have number info. Instead |
| // we have to inspect their backing element in the frame. |
| ASSERT(!is_copy()); |
| if (!is_constant()) { |
| return NumberInfo::FromInt(NumberInfoField::decode(value_)); |
| } |
| Handle<Object> value = handle(); |
| if (value->IsSmi()) return NumberInfo::Smi(); |
| if (value->IsHeapNumber()) return NumberInfo::HeapNumber(); |
| return NumberInfo::Unknown(); |
| } |
| |
| inline void set_number_info(NumberInfo info) { |
| // Copied elements do not have number info. Instead |
| // we have to inspect their backing element in the frame. |
| ASSERT(!is_copy()); |
| value_ = value_ & ~NumberInfoField::mask(); |
| value_ = value_ | NumberInfoField::encode(info.ToInt()); |
| } |
| |
| // The default constructor creates an invalid frame element. |
| FrameElement() { |
| value_ = TypeField::encode(INVALID) |
| | CopiedField::encode(false) |
| | SyncedField::encode(false) |
| | NumberInfoField::encode(NumberInfo::Uninitialized().ToInt()) |
| | DataField::encode(0); |
| } |
| |
| // Factory function to construct an invalid frame element. |
| static FrameElement InvalidElement() { |
| FrameElement result; |
| return result; |
| } |
| |
| // Factory function to construct an in-memory frame element. |
| static FrameElement MemoryElement(NumberInfo info) { |
| FrameElement result(MEMORY, no_reg, SYNCED, info); |
| return result; |
| } |
| |
| // Factory function to construct an in-register frame element. |
| static FrameElement RegisterElement(Register reg, |
| SyncFlag is_synced, |
| NumberInfo info) { |
| return FrameElement(REGISTER, reg, is_synced, info); |
| } |
| |
| // Factory function to construct a frame element whose value is known at |
| // compile time. |
| static FrameElement ConstantElement(Handle<Object> value, |
| SyncFlag is_synced) { |
| FrameElement result(value, is_synced); |
| return result; |
| } |
| |
| // Static indirection table for handles to constants. If a frame |
| // element represents a constant, the data contains an index into |
| // this table of handles to the actual constants. |
| typedef ZoneList<Handle<Object> > ZoneObjectList; |
| |
| static ZoneObjectList* ConstantList(); |
| |
| // Clear the constants indirection table. |
| static void ClearConstantList() { |
| ConstantList()->Clear(); |
| } |
| |
| bool is_synced() const { return SyncedField::decode(value_); } |
| |
| void set_sync() { |
| ASSERT(type() != MEMORY); |
| value_ = value_ | SyncedField::encode(true); |
| } |
| |
| void clear_sync() { |
| ASSERT(type() != MEMORY); |
| value_ = value_ & ~SyncedField::mask(); |
| } |
| |
| bool is_valid() const { return type() != INVALID; } |
| bool is_memory() const { return type() == MEMORY; } |
| bool is_register() const { return type() == REGISTER; } |
| bool is_constant() const { return type() == CONSTANT; } |
| bool is_copy() const { return type() == COPY; } |
| |
| bool is_copied() const { return CopiedField::decode(value_); } |
| void set_copied() { value_ = value_ | CopiedField::encode(true); } |
| void clear_copied() { value_ = value_ & ~CopiedField::mask(); } |
| |
| Register reg() const { |
| ASSERT(is_register()); |
| uint32_t reg = DataField::decode(value_); |
| Register result; |
| result.code_ = reg; |
| return result; |
| } |
| |
| Handle<Object> handle() const { |
| ASSERT(is_constant()); |
| return ConstantList()->at(DataField::decode(value_)); |
| } |
| |
| int index() const { |
| ASSERT(is_copy()); |
| return DataField::decode(value_); |
| } |
| |
| bool Equals(FrameElement other) { |
| uint32_t masked_difference = (value_ ^ other.value_) & ~CopiedField::mask(); |
| if (!masked_difference) { |
| // The elements are equal if they agree exactly except on copied field. |
| return true; |
| } else { |
| // If two constants have the same value, and agree otherwise, return true. |
| return !(masked_difference & ~DataField::mask()) && |
| is_constant() && |
| handle().is_identical_to(other.handle()); |
| } |
| } |
| |
| // Test if two FrameElements refer to the same memory or register location. |
| bool SameLocation(FrameElement* other) { |
| if (type() == other->type()) { |
| if (value_ == other->value_) return true; |
| if (is_constant() && handle().is_identical_to(other->handle())) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| // Given a pair of non-null frame element pointers, return one of them |
| // as an entry frame candidate or null if they are incompatible. |
| FrameElement* Combine(FrameElement* other) { |
| // If either is invalid, the result is. |
| if (!is_valid()) return this; |
| if (!other->is_valid()) return other; |
| |
| if (!SameLocation(other)) return NULL; |
| // If either is unsynced, the result is. |
| FrameElement* result = is_synced() ? other : this; |
| return result; |
| } |
| |
| private: |
| enum Type { |
| INVALID, |
| MEMORY, |
| REGISTER, |
| CONSTANT, |
| COPY |
| }; |
| |
| // Used to construct memory and register elements. |
| FrameElement(Type type, |
| Register reg, |
| SyncFlag is_synced, |
| NumberInfo info) { |
| value_ = TypeField::encode(type) |
| | CopiedField::encode(false) |
| | SyncedField::encode(is_synced != NOT_SYNCED) |
| | NumberInfoField::encode(info.ToInt()) |
| | DataField::encode(reg.code_ > 0 ? reg.code_ : 0); |
| } |
| |
| // Used to construct constant elements. |
| FrameElement(Handle<Object> value, SyncFlag is_synced) { |
| value_ = TypeField::encode(CONSTANT) |
| | CopiedField::encode(false) |
| | SyncedField::encode(is_synced != NOT_SYNCED) |
| | NumberInfoField::encode(NumberInfo::Uninitialized().ToInt()) |
| | DataField::encode(ConstantList()->length()); |
| ConstantList()->Add(value); |
| } |
| |
| Type type() const { return TypeField::decode(value_); } |
| void set_type(Type type) { |
| value_ = value_ & ~TypeField::mask(); |
| value_ = value_ | TypeField::encode(type); |
| } |
| |
| void set_index(int new_index) { |
| ASSERT(is_copy()); |
| value_ = value_ & ~DataField::mask(); |
| value_ = value_ | DataField::encode(new_index); |
| } |
| |
| void set_reg(Register new_reg) { |
| ASSERT(is_register()); |
| value_ = value_ & ~DataField::mask(); |
| value_ = value_ | DataField::encode(new_reg.code_); |
| } |
| |
| // Encode type, copied, synced and data in one 32 bit integer. |
| uint32_t value_; |
| |
| class TypeField: public BitField<Type, 0, 3> {}; |
| class CopiedField: public BitField<bool, 3, 1> {}; |
| class SyncedField: public BitField<bool, 4, 1> {}; |
| class NumberInfoField: public BitField<int, 5, 4> {}; |
| class DataField: public BitField<uint32_t, 9, 32 - 9> {}; |
| |
| friend class VirtualFrame; |
| }; |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_FRAME_ELEMENT_H_ |