// Copyright 2018 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef V8_COMMON_PTR_COMPR_INL_H_ #define V8_COMMON_PTR_COMPR_INL_H_ #include "include/v8-internal.h" #include "src/common/ptr-compr.h" #include "src/execution/isolate.h" #include "src/execution/off-thread-isolate-inl.h" namespace v8 { namespace internal { #if V8_TARGET_ARCH_64_BIT // Compresses full-pointer representation of a tagged value to on-heap // representation. V8_INLINE Tagged_t CompressTagged(Address tagged) { return static_cast<Tagged_t>(static_cast<uint32_t>(tagged)); } V8_INLINE Address GetIsolateRoot(Address on_heap_addr) { // We subtract 1 here in order to let the compiler generate addition of 32-bit // signed constant instead of 64-bit constant (the problem is that 2Gb looks // like a negative 32-bit value). It's correct because we will never use // leftmost address of V8 heap as |on_heap_addr|. return RoundDown<kPtrComprIsolateRootAlignment>(on_heap_addr); } V8_INLINE Address GetIsolateRoot(const Isolate* isolate) { Address isolate_root = isolate->isolate_root(); #ifdef V8_COMPRESS_POINTERS isolate_root = reinterpret_cast<Address>(V8_ASSUME_ALIGNED( reinterpret_cast<void*>(isolate_root), kPtrComprIsolateRootAlignment)); #endif return isolate_root; } V8_INLINE Address GetIsolateRoot(const OffThreadIsolate* isolate) { Address isolate_root = isolate->isolate_root(); #ifdef V8_COMPRESS_POINTERS isolate_root = reinterpret_cast<Address>(V8_ASSUME_ALIGNED( reinterpret_cast<void*>(isolate_root), kPtrComprIsolateRootAlignment)); #endif return isolate_root; } // Decompresses smi value. V8_INLINE Address DecompressTaggedSigned(Tagged_t raw_value) { // For runtime code the upper 32-bits of the Smi value do not matter. return static_cast<Address>(raw_value); } // Decompresses weak or strong heap object pointer or forwarding pointer, // preserving both weak- and smi- tags. template <typename TOnHeapAddress> V8_INLINE Address DecompressTaggedPointer(TOnHeapAddress on_heap_addr, Tagged_t raw_value) { return GetIsolateRoot(on_heap_addr) + static_cast<Address>(raw_value); } // Decompresses any tagged value, preserving both weak- and smi- tags. template <typename TOnHeapAddress> V8_INLINE Address DecompressTaggedAny(TOnHeapAddress on_heap_addr, Tagged_t raw_value) { return DecompressTaggedPointer(on_heap_addr, raw_value); } #ifdef V8_COMPRESS_POINTERS STATIC_ASSERT(kPtrComprHeapReservationSize == Internals::kPtrComprHeapReservationSize); STATIC_ASSERT(kPtrComprIsolateRootAlignment == Internals::kPtrComprIsolateRootAlignment); #endif // V8_COMPRESS_POINTERS #else V8_INLINE Tagged_t CompressTagged(Address tagged) { UNREACHABLE(); } V8_INLINE Address GetIsolateRoot(Address on_heap_addr) { UNREACHABLE(); } V8_INLINE Address GetIsolateRoot(const Isolate* isolate) { UNREACHABLE(); } V8_INLINE Address DecompressTaggedSigned(Tagged_t raw_value) { UNREACHABLE(); } template <typename TOnHeapAddress> V8_INLINE Address DecompressTaggedPointer(TOnHeapAddress on_heap_addr, Tagged_t raw_value) { UNREACHABLE(); } template <typename TOnHeapAddress> V8_INLINE Address DecompressTaggedAny(TOnHeapAddress on_heap_addr, Tagged_t raw_value) { UNREACHABLE(); } #endif // V8_TARGET_ARCH_64_BIT } // namespace internal } // namespace v8 #endif // V8_COMMON_PTR_COMPR_INL_H_