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// 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.
#if !V8_ENABLE_WEBASSEMBLY
#error This header should only be included if WebAssembly is enabled.
#endif // !V8_ENABLE_WEBASSEMBLY
#ifndef V8_WASM_WASM_IMPORT_WRAPPER_CACHE_H_
#define V8_WASM_WASM_IMPORT_WRAPPER_CACHE_H_
#include "src/base/platform/mutex.h"
#include "src/compiler/wasm-compiler.h"
namespace v8 {
namespace internal {
class Counters;
namespace wasm {
class WasmCode;
class WasmEngine;
using FunctionSig = Signature<ValueType>;
// Implements a cache for import wrappers.
class WasmImportWrapperCache {
public:
struct CacheKey {
CacheKey(const compiler::WasmImportCallKind& _kind, const FunctionSig* _sig,
int _expected_arity)
: kind(_kind),
signature(_sig),
expected_arity(_expected_arity == kDontAdaptArgumentsSentinel
? 0
: _expected_arity) {}
bool operator==(const CacheKey& rhs) const {
return kind == rhs.kind && signature == rhs.signature &&
expected_arity == rhs.expected_arity;
}
compiler::WasmImportCallKind kind;
const FunctionSig* signature;
int expected_arity;
};
class CacheKeyHash {
public:
size_t operator()(const CacheKey& key) const {
return base::hash_combine(static_cast<uint8_t>(key.kind), key.signature,
key.expected_arity);
}
};
// Helper class to modify the cache under a lock.
class V8_NODISCARD ModificationScope {
public:
explicit ModificationScope(WasmImportWrapperCache* cache)
: cache_(cache), guard_(&cache->mutex_) {}
V8_EXPORT_PRIVATE WasmCode*& operator[](const CacheKey& key);
private:
WasmImportWrapperCache* const cache_;
base::MutexGuard guard_;
};
// Not thread-safe, use ModificationScope to get exclusive write access to the
// cache.
V8_EXPORT_PRIVATE WasmCode*& operator[](const CacheKey& key);
// Thread-safe. Assumes the key exists in the map.
V8_EXPORT_PRIVATE WasmCode* Get(compiler::WasmImportCallKind kind,
const FunctionSig* sig,
int expected_arity) const;
// Thread-safe. Returns nullptr if the key doesn't exist in the map.
WasmCode* MaybeGet(compiler::WasmImportCallKind kind, const FunctionSig* sig,
int expected_arity) const;
~WasmImportWrapperCache();
private:
mutable base::Mutex mutex_;
std::unordered_map<CacheKey, WasmCode*, CacheKeyHash> entry_map_;
};
} // namespace wasm
} // namespace internal
} // namespace v8
#endif // V8_WASM_WASM_IMPORT_WRAPPER_CACHE_H_
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