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// Copyright 2019 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_EXECUTION_ISOLATE_UTILS_INL_H_
#define V8_EXECUTION_ISOLATE_UTILS_INL_H_
#include "src/common/ptr-compr-inl.h"
#include "src/execution/isolate-utils.h"
#include "src/execution/isolate.h"
#include "src/heap/heap-write-barrier-inl.h"
namespace v8 {
namespace internal {
#ifdef V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE
// Aliases for GetPtrComprCageBase when
// V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE. Each Isolate has its own cage, whose
// base address is also the Isolate root.
V8_INLINE Address GetIsolateRootAddress(Address on_heap_addr) {
return V8HeapCompressionScheme::GetPtrComprCageBaseAddress(on_heap_addr);
}
V8_INLINE Address GetIsolateRootAddress(PtrComprCageBase cage_base) {
return cage_base.address();
}
#else
V8_INLINE Address GetIsolateRootAddress(Address on_heap_addr) { UNREACHABLE(); }
V8_INLINE Address GetIsolateRootAddress(PtrComprCageBase cage_base) {
UNREACHABLE();
}
#endif // V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE
V8_INLINE Heap* GetHeapFromWritableObject(HeapObject object) {
// Avoid using the below GetIsolateFromWritableObject because we want to be
// able to get the heap, but not the isolate, for off-thread objects.
#if defined V8_ENABLE_THIRD_PARTY_HEAP
return Heap::GetIsolateFromWritableObject(object)->heap();
#elif defined(V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE) && \
!defined(V8_EXTERNAL_CODE_SPACE)
Isolate* isolate =
Isolate::FromRootAddress(GetIsolateRootAddress(object.ptr()));
DCHECK_NOT_NULL(isolate);
return isolate->heap();
#else
heap_internals::MemoryChunk* chunk =
heap_internals::MemoryChunk::FromHeapObject(object);
return chunk->GetHeap();
#endif // V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE, V8_ENABLE_THIRD_PARTY_HEAP
}
V8_INLINE Isolate* GetIsolateFromWritableObject(HeapObject object) {
#ifdef V8_ENABLE_THIRD_PARTY_HEAP
return Heap::GetIsolateFromWritableObject(object);
#elif defined(V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE) && \
!defined(V8_EXTERNAL_CODE_SPACE)
Isolate* isolate =
Isolate::FromRootAddress(GetIsolateRootAddress(object.ptr()));
DCHECK_NOT_NULL(isolate);
return isolate;
#else
return Isolate::FromHeap(GetHeapFromWritableObject(object));
#endif // V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE, V8_ENABLE_THIRD_PARTY_HEAP
}
V8_INLINE bool GetIsolateFromHeapObject(HeapObject object, Isolate** isolate) {
#ifdef V8_ENABLE_THIRD_PARTY_HEAP
*isolate = Heap::GetIsolateFromWritableObject(object);
return true;
#elif defined V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE
*isolate = GetIsolateFromWritableObject(object);
return true;
#else
heap_internals::MemoryChunk* chunk =
heap_internals::MemoryChunk::FromHeapObject(object);
if (chunk->InReadOnlySpace()) {
*isolate = nullptr;
return false;
}
*isolate = Isolate::FromHeap(chunk->GetHeap());
return true;
#endif // V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE, V8_ENABLE_THIRD_PARTY_HEAP
}
// Use this function instead of Internals::GetIsolateForSandbox for internal
// code, as this function is fully inlinable.
V8_INLINE static Isolate* GetIsolateForSandbox(HeapObject object) {
#ifdef V8_ENABLE_SANDBOX
return GetIsolateFromWritableObject(object);
#else
// Not used in non-sandbox mode.
return nullptr;
#endif
}
// This is an external code space friendly version of GetPtrComprCageBase(..)
// which also works for objects located in external code space.
//
// NOTE: it's supposed to be used only for the cases where performance doesn't
// matter. For example, in debug only code or in debugging macros.
// In production code the preferred way is to use precomputed cage base value
// which is a result of PtrComprCageBase{isolate} or GetPtrComprCageBase()
// applied to a heap object which is known to not be a part of external code
// space.
V8_INLINE PtrComprCageBase GetPtrComprCageBaseSlow(HeapObject object) {
if (V8_EXTERNAL_CODE_SPACE_BOOL) {
Isolate* isolate;
if (GetIsolateFromHeapObject(object, &isolate)) {
return PtrComprCageBase{isolate};
}
// If the Isolate can't be obtained then the heap object is a read-only
// one and therefore not a Code object, so fallback to auto-computing cage
// base value.
}
return GetPtrComprCageBase(object);
}
} // namespace internal
} // namespace v8
#endif // V8_EXECUTION_ISOLATE_UTILS_INL_H_
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