diff options
Diffstat (limited to 'deps/v8/src/frame-element.h')
| -rw-r--r-- | deps/v8/src/frame-element.h | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/deps/v8/src/frame-element.h b/deps/v8/src/frame-element.h new file mode 100644 index 000000000..d16eb481a --- /dev/null +++ b/deps/v8/src/frame-element.h @@ -0,0 +1,265 @@ +// 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 "register-allocator-inl.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 + }; + + // The default constructor creates an invalid frame element. + FrameElement() { + value_ = StaticTypeField::encode(StaticType::UNKNOWN_TYPE) + | TypeField::encode(INVALID) + | CopiedField::encode(false) + | SyncedField::encode(false) + | 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() { + FrameElement result(MEMORY, no_reg, SYNCED); + return result; + } + + // Factory function to construct an in-register frame element. + static FrameElement RegisterElement(Register reg, + SyncFlag is_synced, + StaticType static_type = StaticType()) { + return FrameElement(REGISTER, reg, is_synced, static_type); + } + + // 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() { + static ZoneObjectList list(10); + return &list; + } + + // 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_); + } + + StaticType static_type() { + return StaticType(StaticTypeField::decode(value_)); + } + + void set_static_type(StaticType static_type) { + value_ = value_ & ~StaticTypeField::mask(); + value_ = value_ | StaticTypeField::encode(static_type.static_type_); + } + + 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. The result static type is + // the merge of the static types. It's safe to set it on one of the + // frame elements, and harmless too (because we are only going to + // merge the reaching frames and will ensure that the types are + // coherent, and changing the static type does not emit code). + FrameElement* result = is_synced() ? other : this; + result->set_static_type(static_type().merge(other->static_type())); + 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) { + value_ = StaticTypeField::encode(StaticType::UNKNOWN_TYPE) + | TypeField::encode(type) + | CopiedField::encode(false) + | SyncedField::encode(is_synced != NOT_SYNCED) + | DataField::encode(reg.code_ > 0 ? reg.code_ : 0); + } + + FrameElement(Type type, Register reg, SyncFlag is_synced, StaticType stype) { + value_ = StaticTypeField::encode(stype.static_type_) + | TypeField::encode(type) + | CopiedField::encode(false) + | SyncedField::encode(is_synced != NOT_SYNCED) + | DataField::encode(reg.code_ > 0 ? reg.code_ : 0); + } + + // Used to construct constant elements. + FrameElement(Handle<Object> value, SyncFlag is_synced) { + value_ = StaticTypeField::encode(StaticType::TypeOf(*value).static_type_) + | TypeField::encode(CONSTANT) + | CopiedField::encode(false) + | SyncedField::encode(is_synced != NOT_SYNCED) + | 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 static type, type, copied, synced and data in one 32 bit integer. + uint32_t value_; + + class StaticTypeField: public BitField<StaticType::StaticTypeEnum, 0, 3> {}; + class TypeField: public BitField<Type, 3, 3> {}; + class CopiedField: public BitField<uint32_t, 6, 1> {}; + class SyncedField: public BitField<uint32_t, 7, 1> {}; + class DataField: public BitField<uint32_t, 8, 32 - 9> {}; + + friend class VirtualFrame; +}; + +} } // namespace v8::internal + +#endif // V8_FRAME_ELEMENT_H_ |