V8 API Reference, 7.2.502.16 (for Deno 0.2.4)
wasm-value.h
1 // Copyright 2017 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8_WASM_WASM_VALUE_H_
6 #define V8_WASM_WASM_VALUE_H_
7 
8 #include "src/boxed-float.h"
9 #include "src/v8memory.h"
10 #include "src/wasm/wasm-opcodes.h"
11 #include "src/zone/zone-containers.h"
12 
13 namespace v8 {
14 namespace internal {
15 namespace wasm {
16 
17 #define FOREACH_SIMD_TYPE(V) \
18  V(float, float4, f32x4, 4) \
19  V(int32_t, int4, i32x4, 4) \
20  V(int16_t, int8, i16x8, 8) \
21  V(int8_t, int16, i8x16, 16)
22 
23 #define DEFINE_SIMD_TYPE(cType, sType, name, kSize) \
24  struct sType { \
25  cType val[kSize]; \
26  };
27 FOREACH_SIMD_TYPE(DEFINE_SIMD_TYPE)
28 #undef DEFINE_SIMD_TYPE
29 
30 class Simd128 {
31  public:
32  Simd128() : val_() {
33  for (size_t i = 0; i < 16; i++) {
34  val_[i] = 0;
35  }
36  }
37 #define DEFINE_SIMD_TYPE_SPECIFIC_METHODS(cType, sType, name, size) \
38  explicit Simd128(sType val) { \
39  WriteUnalignedValue<sType>(reinterpret_cast<Address>(val_), val); \
40  } \
41  sType to_##name() { \
42  return ReadUnalignedValue<sType>(reinterpret_cast<Address>(val_)); \
43  }
44  FOREACH_SIMD_TYPE(DEFINE_SIMD_TYPE_SPECIFIC_METHODS)
45 #undef DEFINE_SIMD_TYPE_SPECIFIC_METHODS
46 
47  private:
48  uint8_t val_[16];
49 };
50 
51 // Macro for defining WasmValue methods for different types.
52 // Elements:
53 // - name (for to_<name>() method)
54 // - wasm type
55 // - c type
56 #define FOREACH_WASMVAL_TYPE(V) \
57  V(i32, kWasmI32, int32_t) \
58  V(u32, kWasmI32, uint32_t) \
59  V(i64, kWasmI64, int64_t) \
60  V(u64, kWasmI64, uint64_t) \
61  V(f32, kWasmF32, float) \
62  V(f32_boxed, kWasmF32, Float32) \
63  V(f64, kWasmF64, double) \
64  V(f64_boxed, kWasmF64, Float64) \
65  V(s128, kWasmS128, Simd128)
66 
67 // A wasm value with type information.
68 class WasmValue {
69  public:
70  WasmValue() : type_(kWasmStmt), bit_pattern_{} {}
71 
72 #define DEFINE_TYPE_SPECIFIC_METHODS(name, localtype, ctype) \
73  explicit WasmValue(ctype v) : type_(localtype), bit_pattern_{} { \
74  static_assert(sizeof(ctype) <= sizeof(bit_pattern_), \
75  "size too big for WasmValue"); \
76  WriteUnalignedValue<ctype>(reinterpret_cast<Address>(bit_pattern_), v); \
77  } \
78  ctype to_##name() const { \
79  DCHECK_EQ(localtype, type_); \
80  return to_##name##_unchecked(); \
81  } \
82  ctype to_##name##_unchecked() const { \
83  return ReadUnalignedValue<ctype>(reinterpret_cast<Address>(bit_pattern_)); \
84  }
85  FOREACH_WASMVAL_TYPE(DEFINE_TYPE_SPECIFIC_METHODS)
86 #undef DEFINE_TYPE_SPECIFIC_METHODS
87 
88  ValueType type() const { return type_; }
89 
90  // Checks equality of type and bit pattern (also for float and double values).
91  bool operator==(const WasmValue& other) const {
92  return type_ == other.type_ &&
93  !memcmp(bit_pattern_, other.bit_pattern_, 16);
94  }
95 
96  template <typename T>
97  inline T to() const;
98 
99  template <typename T>
100  inline T to_unchecked() const;
101 
102  private:
103  ValueType type_;
104  uint8_t bit_pattern_[16];
105 };
106 
107 #define DECLARE_CAST(name, localtype, ctype, ...) \
108  template <> \
109  inline ctype WasmValue::to_unchecked() const { \
110  return to_##name##_unchecked(); \
111  } \
112  template <> \
113  inline ctype WasmValue::to() const { \
114  return to_##name(); \
115  }
116 FOREACH_WASMVAL_TYPE(DECLARE_CAST)
117 #undef DECLARE_CAST
118 
119 } // namespace wasm
120 } // namespace internal
121 } // namespace v8
122 
123 #endif // V8_WASM_WASM_VALUE_H_
Definition: libplatform.h:13