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// Copyright 2017 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_VISITORS_H_
#define V8_VISITORS_H_
#include "src/globals.h"
namespace v8 {
namespace internal {
class CodeDataContainer;
class Object;
#define ROOT_ID_LIST(V) \
V(kStringTable, "string_table", "(Internalized strings)") \
V(kExternalStringsTable, "external_strings_table", "(External strings)") \
V(kStrongRootList, "strong_root_list", "(Strong roots)") \
V(kSmiRootList, "smi_root_list", "(Smi roots)") \
V(kBootstrapper, "bootstrapper", "(Bootstrapper)") \
V(kTop, "top", "(Isolate)") \
V(kRelocatable, "relocatable", "(Relocatable)") \
V(kDebug, "debug", "(Debugger)") \
V(kCompilationCache, "compilationcache", "(Compilation cache)") \
V(kHandleScope, "handlescope", "(Handle scope)") \
V(kDispatchTable, "dispatchtable", "(Dispatch table)") \
V(kBuiltins, "builtins", "(Builtins)") \
V(kGlobalHandles, "globalhandles", "(Global handles)") \
V(kEternalHandles, "eternalhandles", "(Eternal handles)") \
V(kThreadManager, "threadmanager", "(Thread manager)") \
V(kStrongRoots, "strong roots", "(Strong roots)") \
V(kExtensions, "Extensions", "(Extensions)")
class VisitorSynchronization : public AllStatic {
public:
#define DECLARE_ENUM(enum_item, ignore1, ignore2) enum_item,
enum SyncTag { ROOT_ID_LIST(DECLARE_ENUM) kNumberOfSyncTags };
#undef DECLARE_ENUM
static const char* const kTags[kNumberOfSyncTags];
static const char* const kTagNames[kNumberOfSyncTags];
};
enum class Root {
#define DECLARE_ENUM(enum_item, ignore1, ignore2) enum_item,
ROOT_ID_LIST(DECLARE_ENUM)
#undef DECLARE_ENUM
// TODO(ulan): Merge with the ROOT_ID_LIST.
kCodeFlusher,
kPartialSnapshotCache,
kWeakCollections,
kWrapperTracing,
kUnknown
};
// Abstract base class for visiting, and optionally modifying, the
// pointers contained in roots. Used in GC and serialization/deserialization.
class RootVisitor BASE_EMBEDDED {
public:
virtual ~RootVisitor() {}
// Visits a contiguous arrays of pointers in the half-open range
// [start, end). Any or all of the values may be modified on return.
virtual void VisitRootPointers(Root root, Object** start, Object** end) = 0;
// Handy shorthand for visiting a single pointer.
virtual void VisitRootPointer(Root root, Object** p) {
VisitRootPointers(root, p, p + 1);
}
// Intended for serialization/deserialization checking: insert, or
// check for the presence of, a tag at this position in the stream.
// Also used for marking up GC roots in heap snapshots.
// TODO(ulan): Remove this.
virtual void Synchronize(VisitorSynchronization::SyncTag tag) {}
};
// Abstract base class for visiting, and optionally modifying, the
// pointers contained in Objects. Used in GC and serialization/deserialization.
class ObjectVisitor BASE_EMBEDDED {
public:
virtual ~ObjectVisitor() {}
// Visits a contiguous arrays of pointers in the half-open range
// [start, end). Any or all of the values may be modified on return.
virtual void VisitPointers(HeapObject* host, Object** start,
Object** end) = 0;
// Handy shorthand for visiting a single pointer.
virtual void VisitPointer(HeapObject* host, Object** p) {
VisitPointers(host, p, p + 1);
}
// To allow lazy clearing of inline caches the visitor has
// a rich interface for iterating over Code objects ...
// Visits a code target in the instruction stream.
virtual void VisitCodeTarget(Code* host, RelocInfo* rinfo);
// Visits a runtime entry in the instruction stream.
virtual void VisitRuntimeEntry(Code* host, RelocInfo* rinfo) {}
// Visit pointer embedded into a code object.
virtual void VisitEmbeddedPointer(Code* host, RelocInfo* rinfo);
// Visits an external reference embedded into a code object.
virtual void VisitExternalReference(Code* host, RelocInfo* rinfo) {}
// Visits an external reference.
virtual void VisitExternalReference(Foreign* host, Address* p) {}
// Visits an (encoded) internal reference.
virtual void VisitInternalReference(Code* host, RelocInfo* rinfo) {}
};
} // namespace internal
} // namespace v8
#endif // V8_VISITORS_H_