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/*
* Copyright 2017 WebAssembly Community Group participants
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef wasm_wasm_type_h
#define wasm_wasm_type_h
#include "wasm-features.h"
#include <ostream>
#include <vector>
// TODO: At various code locations we were assuming that single types are basic
// types, but this is going to change with the introduction of the compound
// Signature, Struct and Array types that will be single but not basic. To
// prepare for this change, the following macro marks affected code locations.
#define TODO_SINGLE_COMPOUND(type) \
assert(!type.isMulti() && "Unexpected multi-value type"); \
assert(!type.isCompound() && "TODO: handle compound types");
namespace wasm {
class Type {
// The `id` uniquely represents each type, so type equality is just a
// comparison of the ids. For basic types the `id` is just the `ValueType`
// enum value below, and for constructed types the `id` is the address of the
// canonical representation of the type, making lookups cheap for all types.
uintptr_t id;
void init(const std::vector<Type>&);
public:
enum ValueType : uint32_t {
none,
unreachable,
i32,
i64,
f32,
f64,
v128,
funcref,
externref,
nullref,
exnref,
_last_value_type = exnref
};
Type() = default;
// ValueType can be implicitly upgraded to Type
constexpr Type(ValueType id) : id(id){};
// But converting raw uint32_t is more dangerous, so make it explicit
explicit Type(uint64_t id) : id(id){};
// Construct from lists of elementary types
Type(std::initializer_list<Type> types);
explicit Type(const std::vector<Type>& types);
// Accessors
size_t size() const;
const std::vector<Type>& expand() const;
// Predicates
// Compound Concrete
// Type Basic │ Single│
// ╒═════════════╦═│═╤═│═╤═│═╤═│═╤═══════╕
// │ none ║ x │ │ │ │ │
// │ unreachable ║ x │ │ │ │ │
// ├─────────────╫───┼───┼───┼───┤───────┤
// │ i32 ║ x │ │ x │ x │ I │ ┐ Number
// │ i64 ║ x │ │ x │ x │ I │ │ I_nteger
// │ f32 ║ x │ │ x │ x │ F │ │ F_loat
// │ f64 ║ x │ │ x │ x │ F │ │ V_ector
// │ v128 ║ x │ │ x │ x │ V │ ┘
// ├─────────────╫───┼───┼───┼───┤───────┤
// │ funcref ║ x │ │ x │ x │ f │ ┐ Ref
// │ externref ║ x │ │ x │ x │ │ │ f_unc
// │ nullref ║ x │ │ x │ x │ │ │
// │ exnref ║ x │ │ x │ x │ │ │
// ├─────────────╫───┼───┼───┼───┤───────┤ │
// │ Signature ║ │ x │ x │ x │ f │ │ ┐
// │ Struct ║ │ x │ x │ x │ │ │ │ TODO (GC)
// │ Array ║ │ x │ x │ x │ │ ┘ ┘
// │ Multi ║ │ x │ │ x │ │
// └─────────────╨───┴───┴───┴───┴───────┘
constexpr bool isBasic() const { return id <= _last_value_type; }
constexpr bool isCompound() const { return id > _last_value_type; }
constexpr bool isSingle() const {
// TODO: Compound types Signature, Struct and Array are single
return id >= i32 && id <= _last_value_type;
}
constexpr bool isMulti() const {
// TODO: Compound types Signature, Struct and Array are not multi
return id > _last_value_type;
}
constexpr bool isConcrete() const { return id >= i32; }
constexpr bool isInteger() const { return id == i32 || id == i64; }
constexpr bool isFloat() const { return id == f32 || id == f64; }
constexpr bool isVector() const { return id == v128; };
constexpr bool isNumber() const { return id >= i32 && id <= v128; }
constexpr bool isRef() const {
// TODO: Compound types Signature, Struct and Array are ref
return id >= funcref && id <= exnref;
}
private:
template<bool (Type::*pred)() const> bool hasPredicate() {
for (auto t : expand()) {
if ((t.*pred)()) {
return true;
}
}
return false;
}
public:
bool hasVector() { return hasPredicate<&Type::isVector>(); }
bool hasRef() { return hasPredicate<&Type::isRef>(); }
constexpr uint64_t getID() const { return id; }
constexpr ValueType getBasic() const {
assert(isBasic() && "Basic type expected");
return static_cast<ValueType>(id);
}
// (In)equality must be defined for both Type and ValueType because it is
// otherwise ambiguous whether to convert both this and other to int or
// convert other to Type.
bool operator==(const Type& other) const { return id == other.id; }
bool operator==(const ValueType& other) const { return id == other; }
bool operator!=(const Type& other) const { return id != other.id; }
bool operator!=(const ValueType& other) const { return id != other; }
// Order types by some notion of simplicity
bool operator<(const Type& other) const;
// Returns the type size in bytes. Only single types are supported.
unsigned getByteSize() const;
// Reinterpret an integer type to a float type with the same size and vice
// versa. Only single integer and float types are supported.
Type reinterpret() const;
// Returns the feature set required to use this type.
FeatureSet getFeatures() const;
// Returns a number type based on its size in bytes and whether it is a float
// type.
static Type get(unsigned byteSize, bool float_);
// Returns true if left is a subtype of right. Subtype includes itself.
static bool isSubType(Type left, Type right);
// Computes the least upper bound from the type lattice.
// If one of the type is unreachable, the other type becomes the result. If
// the common supertype does not exist, returns none, a poison value.
static Type getLeastUpperBound(Type a, Type b);
// Computes the least upper bound for all types in the given list.
template<typename T> static Type mergeTypes(const T& types) {
Type type = Type::unreachable;
for (auto other : types) {
type = Type::getLeastUpperBound(type, other);
}
return type;
}
std::string toString() const;
};
// Wrapper type for formatting types as "(param i32 i64 f32)"
struct ParamType {
Type type;
ParamType(Type type) : type(type) {}
std::string toString() const;
};
// Wrapper type for formatting types as "(result i32 i64 f32)"
struct ResultType {
Type type;
ResultType(Type type) : type(type) {}
std::string toString() const;
};
struct Signature {
Type params;
Type results;
Signature() : params(Type::none), results(Type::none) {}
Signature(Type params, Type results) : params(params), results(results) {}
bool operator==(const Signature& other) const {
return params == other.params && results == other.results;
}
bool operator!=(const Signature& other) const { return !(*this == other); }
bool operator<(const Signature& other) const;
};
std::ostream& operator<<(std::ostream& os, Type t);
std::ostream& operator<<(std::ostream& os, ParamType t);
std::ostream& operator<<(std::ostream& os, ResultType t);
std::ostream& operator<<(std::ostream& os, Signature t);
} // namespace wasm
namespace std {
template<> class hash<wasm::Type> {
public:
size_t operator()(const wasm::Type& type) const;
};
template<> class hash<wasm::Signature> {
public:
size_t operator()(const wasm::Signature& sig) const;
};
} // namespace std
#endif // wasm_wasm_type_h
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