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// Copyright 2021 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_CONSTANT_EXPRESSION_INTERFACE_H_
#define V8_WASM_CONSTANT_EXPRESSION_INTERFACE_H_
#include "src/wasm/decoder.h"
#include "src/wasm/function-body-decoder-impl.h"
#include "src/wasm/wasm-value.h"
namespace v8 {
namespace internal {
class WasmInstanceObject;
class JSArrayBuffer;
namespace wasm {
// An interface for WasmFullDecoder used to decode constant expressions.
// This interface has two modes: only validation (when {isolate_ == nullptr}),
// and code-generation (when {isolate_ != nullptr}). We merge two distinct
// functionalities in one class to reduce the number of WasmFullDecoder
// instantiations, and thus V8 binary code size.
// In code-generation mode, the result can be retrieved with {computed_value()}
// if {!has_error()}, or with {error()} otherwise.
class V8_EXPORT_PRIVATE ConstantExpressionInterface {
public:
static constexpr Decoder::ValidateFlag validate = Decoder::kFullValidation;
static constexpr DecodingMode decoding_mode = kConstantExpression;
struct Value : public ValueBase<validate> {
WasmValue runtime_value;
template <typename... Args>
explicit Value(Args&&... args) V8_NOEXCEPT
: ValueBase(std::forward<Args>(args)...) {}
};
using Control = ControlBase<Value, validate>;
using FullDecoder =
WasmFullDecoder<validate, ConstantExpressionInterface, decoding_mode>;
ConstantExpressionInterface(const WasmModule* module, Isolate* isolate,
Handle<WasmInstanceObject> instance)
: module_(module),
outer_module_(nullptr),
isolate_(isolate),
instance_(instance) {
DCHECK_NOT_NULL(isolate);
}
explicit ConstantExpressionInterface(WasmModule* outer_module)
: module_(nullptr), outer_module_(outer_module), isolate_(nullptr) {}
#define EMPTY_INTERFACE_FUNCTION(name, ...) \
V8_INLINE void name(FullDecoder* decoder, ##__VA_ARGS__) {}
INTERFACE_META_FUNCTIONS(EMPTY_INTERFACE_FUNCTION)
#undef EMPTY_INTERFACE_FUNCTION
#define UNREACHABLE_INTERFACE_FUNCTION(name, ...) \
V8_INLINE void name(FullDecoder* decoder, ##__VA_ARGS__) { UNREACHABLE(); }
INTERFACE_NON_CONSTANT_FUNCTIONS(UNREACHABLE_INTERFACE_FUNCTION)
#undef UNREACHABLE_INTERFACE_FUNCTION
#define DECLARE_INTERFACE_FUNCTION(name, ...) \
void name(FullDecoder* decoder, ##__VA_ARGS__);
INTERFACE_CONSTANT_FUNCTIONS(DECLARE_INTERFACE_FUNCTION)
#undef DECLARE_INTERFACE_FUNCTION
WasmValue computed_value() const {
DCHECK(generate_value());
// The value has to be initialized.
DCHECK_NE(computed_value_.type(), kWasmVoid);
return computed_value_;
}
bool end_found() const { return end_found_; }
bool has_error() const { return error_ != MessageTemplate::kNone; }
MessageTemplate error() const {
DCHECK(has_error());
DCHECK_EQ(computed_value_.type(), kWasmVoid);
return error_;
}
private:
bool generate_value() const { return isolate_ != nullptr && !has_error(); }
bool end_found_ = false;
WasmValue computed_value_;
MessageTemplate error_ = MessageTemplate::kNone;
const WasmModule* module_;
WasmModule* outer_module_;
Isolate* isolate_;
Handle<WasmInstanceObject> instance_;
};
} // namespace wasm
} // namespace internal
} // namespace v8
#endif // V8_WASM_CONSTANT_EXPRESSION_INTERFACE_H_
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