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// Copyright 2021 The Tint Authors.
//
// 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 SRC_TINT_SEM_VARIABLE_H_
#define SRC_TINT_SEM_VARIABLE_H_
#include <optional>
#include <utility>
#include <vector>
#include "tint/override_id.h"
#include "src/tint/ast/access.h"
#include "src/tint/ast/address_space.h"
#include "src/tint/ast/parameter.h"
#include "src/tint/sem/binding_point.h"
#include "src/tint/sem/expression.h"
#include "src/tint/sem/parameter_usage.h"
#include "src/tint/type/type.h"
#include "src/tint/utils/unique_vector.h"
// Forward declarations
namespace tint::ast {
class IdentifierExpression;
class Parameter;
class Variable;
} // namespace tint::ast
namespace tint::sem {
class CallTarget;
class VariableUser;
} // namespace tint::sem
namespace tint::sem {
/// Variable is the base class for local variables, global variables and
/// parameters.
class Variable : public Castable<Variable, Node> {
public:
/// Constructor
/// @param declaration the AST declaration node
/// @param type the variable type
/// @param stage the evaluation stage for an expression of this variable type
/// @param address_space the variable address space
/// @param access the variable access control type
/// @param constant_value the constant value for the variable. May be null
Variable(const ast::Variable* declaration,
const type::Type* type,
EvaluationStage stage,
ast::AddressSpace address_space,
ast::Access access,
const Constant* constant_value);
/// Destructor
~Variable() override;
/// @returns the AST declaration node
const ast::Variable* Declaration() const { return declaration_; }
/// @returns the canonical type for the variable
const type::Type* Type() const { return type_; }
/// @returns the evaluation stage for an expression of this variable type
EvaluationStage Stage() const { return stage_; }
/// @returns the address space for the variable
ast::AddressSpace AddressSpace() const { return address_space_; }
/// @returns the access control for the variable
ast::Access Access() const { return access_; }
/// @return the constant value of this expression
const Constant* ConstantValue() const { return constant_value_; }
/// @returns the variable initializer expression, or nullptr if the variable
/// does not have one.
const Expression* Initializer() const { return initializer_; }
/// Sets the variable initializer expression.
/// @param initializer the initializer expression to assign to this variable.
void SetInitializer(const Expression* initializer) { initializer_ = initializer; }
/// @returns the expressions that use the variable
const std::vector<const VariableUser*>& Users() const { return users_; }
/// @param user the user to add
void AddUser(const VariableUser* user) { users_.emplace_back(user); }
private:
const ast::Variable* const declaration_;
const type::Type* const type_;
const EvaluationStage stage_;
const ast::AddressSpace address_space_;
const ast::Access access_;
const Constant* constant_value_;
const Expression* initializer_ = nullptr;
std::vector<const VariableUser*> users_;
};
/// LocalVariable is a function-scope variable
class LocalVariable final : public Castable<LocalVariable, Variable> {
public:
/// Constructor
/// @param declaration the AST declaration node
/// @param type the variable type
/// @param stage the evaluation stage for an expression of this variable type
/// @param address_space the variable address space
/// @param access the variable access control type
/// @param statement the statement that declared this local variable
/// @param constant_value the constant value for the variable. May be null
LocalVariable(const ast::Variable* declaration,
const type::Type* type,
EvaluationStage stage,
ast::AddressSpace address_space,
ast::Access access,
const sem::Statement* statement,
const Constant* constant_value);
/// Destructor
~LocalVariable() override;
/// @returns the statement that declares this local variable
const sem::Statement* Statement() const { return statement_; }
/// @returns the Type, Function or Variable that this local variable shadows
const CastableBase* Shadows() const { return shadows_; }
/// Sets the Type, Function or Variable that this local variable shadows
/// @param shadows the Type, Function or Variable that this variable shadows
void SetShadows(const CastableBase* shadows) { shadows_ = shadows; }
private:
const sem::Statement* const statement_;
const CastableBase* shadows_ = nullptr;
};
/// GlobalVariable is a module-scope variable
class GlobalVariable final : public Castable<GlobalVariable, Variable> {
public:
/// Constructor
/// @param declaration the AST declaration node
/// @param type the variable type
/// @param stage the evaluation stage for an expression of this variable type
/// @param address_space the variable address space
/// @param access the variable access control type
/// @param constant_value the constant value for the variable. May be null
/// @param binding_point the optional resource binding point of the variable
/// @param location the location value if provided
///
/// Note, a GlobalVariable generally doesn't have a `location` in WGSL, as it isn't allowed by
/// the spec. The location maybe attached by transforms such as CanonicalizeEntryPointIO.
GlobalVariable(const ast::Variable* declaration,
const type::Type* type,
EvaluationStage stage,
ast::AddressSpace address_space,
ast::Access access,
const Constant* constant_value,
sem::BindingPoint binding_point = {},
std::optional<uint32_t> location = std::nullopt);
/// Destructor
~GlobalVariable() override;
/// @returns the resource binding point for the variable
sem::BindingPoint BindingPoint() const { return binding_point_; }
/// @param id the constant identifier to assign to this variable
void SetOverrideId(OverrideId id) { override_id_ = id; }
/// @returns the pipeline constant ID associated with the variable
tint::OverrideId OverrideId() const { return override_id_; }
/// @returns the location value for the parameter, if set
std::optional<uint32_t> Location() const { return location_; }
private:
const sem::BindingPoint binding_point_;
tint::OverrideId override_id_;
std::optional<uint32_t> location_;
};
/// Parameter is a function parameter
class Parameter final : public Castable<Parameter, Variable> {
public:
/// Constructor for function parameters
/// @param declaration the AST declaration node
/// @param index the index of the parmeter in the function
/// @param type the variable type
/// @param address_space the variable address space
/// @param access the variable access control type
/// @param usage the semantic usage for the parameter
/// @param binding_point the optional resource binding point of the parameter
/// @param location the location value, if set
Parameter(const ast::Parameter* declaration,
uint32_t index,
const type::Type* type,
ast::AddressSpace address_space,
ast::Access access,
const ParameterUsage usage = ParameterUsage::kNone,
sem::BindingPoint binding_point = {},
std::optional<uint32_t> location = std::nullopt);
/// Destructor
~Parameter() override;
/// @returns the AST declaration node
const ast::Parameter* Declaration() const {
return static_cast<const ast::Parameter*>(Variable::Declaration());
}
/// @return the index of the parameter in the function
uint32_t Index() const { return index_; }
/// @returns the semantic usage for the parameter
ParameterUsage Usage() const { return usage_; }
/// @returns the CallTarget owner of this parameter
CallTarget const* Owner() const { return owner_; }
/// @param owner the CallTarget owner of this parameter
void SetOwner(CallTarget const* owner) { owner_ = owner; }
/// @returns the Type, Function or Variable that this local variable shadows
const CastableBase* Shadows() const { return shadows_; }
/// Sets the Type, Function or Variable that this local variable shadows
/// @param shadows the Type, Function or Variable that this variable shadows
void SetShadows(const CastableBase* shadows) { shadows_ = shadows; }
/// @returns the resource binding point for the parameter
sem::BindingPoint BindingPoint() const { return binding_point_; }
/// @returns the location value for the parameter, if set
std::optional<uint32_t> Location() const { return location_; }
private:
const uint32_t index_;
const ParameterUsage usage_;
CallTarget const* owner_ = nullptr;
const CastableBase* shadows_ = nullptr;
const sem::BindingPoint binding_point_;
const std::optional<uint32_t> location_;
};
/// VariableUser holds the semantic information for an identifier expression
/// node that resolves to a variable.
class VariableUser final : public Castable<VariableUser, Expression> {
public:
/// Constructor
/// @param declaration the AST identifier node
/// @param statement the statement that owns this expression
/// @param variable the semantic variable
VariableUser(const ast::IdentifierExpression* declaration,
Statement* statement,
sem::Variable* variable);
~VariableUser() override;
/// @returns the variable that this expression refers to
const sem::Variable* Variable() const { return variable_; }
private:
const sem::Variable* const variable_;
};
/// A pair of sem::Variables. Can be hashed.
typedef std::pair<const Variable*, const Variable*> VariablePair;
} // namespace tint::sem
namespace std {
/// Custom std::hash specialization for VariablePair
template <>
class hash<tint::sem::VariablePair> {
public:
/// @param i the variable pair to create a hash for
/// @return the hash value
inline std::size_t operator()(const tint::sem::VariablePair& i) const {
return tint::utils::Hash(i.first, i.second);
}
};
} // namespace std
#endif // SRC_TINT_SEM_VARIABLE_H_