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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_STATEMENT_H_
#define SRC_TINT_SEM_STATEMENT_H_
#include "src/tint/sem/behavior.h"
#include "src/tint/sem/node.h"
#include "src/tint/symbol.h"
#include "src/tint/utils/hashmap.h"
// Forward declarations
namespace tint::ast {
class Statement;
} // namespace tint::ast
namespace tint::sem {
class BlockStatement;
class CompoundStatement;
class Function;
class LocalVariable;
} // namespace tint::sem
namespace tint::sem {
namespace detail {
/// FindFirstParentReturn is a traits helper for determining the return type for
/// the template member function Statement::FindFirstParent().
/// For zero or multiple template arguments, FindFirstParentReturn::type
/// resolves to CompoundStatement.
template <typename... TYPES>
struct FindFirstParentReturn {
/// The pointer type returned by Statement::FindFirstParent()
using type = CompoundStatement;
};
/// A specialization of FindFirstParentReturn for a single template argument.
/// FindFirstParentReturn::type resolves to the single template argument.
template <typename T>
struct FindFirstParentReturn<T> {
/// The pointer type returned by Statement::FindFirstParent()
using type = T;
};
template <typename... TYPES>
using FindFirstParentReturnType = typename FindFirstParentReturn<TYPES...>::type;
} // namespace detail
/// Statement holds the semantic information for a statement.
class Statement : public Castable<Statement, Node> {
public:
/// Constructor
/// @param declaration the AST node for this statement
/// @param parent the owning statement
/// @param function the owning function
Statement(const ast::Statement* declaration,
const CompoundStatement* parent,
const sem::Function* function);
/// Destructor
~Statement() override;
/// @return the AST node for this statement
const ast::Statement* Declaration() const { return declaration_; }
/// @return the statement that encloses this statement
const CompoundStatement* Parent() const { return parent_; }
/// @returns the closest enclosing parent that satisfies the given predicate,
/// which may be the statement itself, or nullptr if no match is found.
/// @param pred a predicate that the resulting block must satisfy
template <typename Pred>
const CompoundStatement* FindFirstParent(Pred&& pred) const;
/// @returns the closest enclosing parent that is of one of the types in
/// `TYPES`, which may be the statement itself, or nullptr if no match is
/// found. If `TYPES` is a single template argument, the return type is a
/// pointer to that template argument type, otherwise a CompoundStatement
/// pointer is returned.
template <typename... TYPES>
const detail::FindFirstParentReturnType<TYPES...>* FindFirstParent() const;
/// @return the closest enclosing block for this statement
const BlockStatement* Block() const;
/// @returns the function that owns this statement
const sem::Function* Function() const { return function_; }
/// @return the behaviors of this statement
const sem::Behaviors& Behaviors() const { return behaviors_; }
/// @return the behaviors of this statement
sem::Behaviors& Behaviors() { return behaviors_; }
/// @returns true if this statement is reachable by control flow according to
/// the behavior analysis
bool IsReachable() const { return is_reachable_; }
/// @param is_reachable whether this statement is reachable by control flow
/// according to the behavior analysis
void SetIsReachable(bool is_reachable) { is_reachable_ = is_reachable; }
private:
const ast::Statement* const declaration_;
const CompoundStatement* const parent_;
const sem::Function* const function_;
sem::Behaviors behaviors_{sem::Behavior::kNext};
bool is_reachable_ = true;
};
/// CompoundStatement is the base class of statements that can hold other
/// statements.
class CompoundStatement : public Castable<Statement, Statement> {
public:
/// Constructor
/// @param declaration the AST node for this statement
/// @param statement the owning statement
/// @param function the owning function
CompoundStatement(const ast::Statement* declaration,
const CompoundStatement* statement,
const sem::Function* function);
/// Destructor
~CompoundStatement() override;
/// OrderedLocalVariable describes a local variable declaration, and order of declaration.
struct OrderedLocalVariable {
/// The 0-based declaration order index of the variable
size_t order;
/// The variable
const LocalVariable* variable;
};
/// @returns a map of variable name to variable declarations associated with this block
const utils::Hashmap<Symbol, OrderedLocalVariable, 4>& Decls() const { return decls_; }
/// Associates a declaration with this block.
/// @note this method must be called in variable declaration order
/// @param var a variable declaration to be added to the block
void AddDecl(const LocalVariable* var);
private:
utils::Hashmap<Symbol, OrderedLocalVariable, 4> decls_;
};
template <typename Pred>
const CompoundStatement* Statement::FindFirstParent(Pred&& pred) const {
if (auto* self = As<CompoundStatement>()) {
if (pred(self)) {
return self;
}
}
const auto* curr = parent_;
while (curr && !pred(curr)) {
curr = curr->Parent();
}
return curr;
}
template <typename... TYPES>
const detail::FindFirstParentReturnType<TYPES...>* Statement::FindFirstParent() const {
using ReturnType = detail::FindFirstParentReturnType<TYPES...>;
if (sizeof...(TYPES) == 1) {
if (auto* p = As<ReturnType>()) {
return p;
}
const auto* curr = parent_;
while (curr) {
if (auto* p = curr->As<ReturnType>()) {
return p;
}
curr = curr->Parent();
}
} else {
if (IsAnyOf<TYPES...>()) {
return As<ReturnType>();
}
const auto* curr = parent_;
while (curr) {
if (curr->IsAnyOf<TYPES...>()) {
return curr->As<ReturnType>();
}
curr = curr->Parent();
}
}
return nullptr;
}
} // namespace tint::sem
#endif // SRC_TINT_SEM_STATEMENT_H_