src/tint/resolver/sem_helper.h

// Copyright 2022 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_RESOLVER_SEM_HELPER_H_
#define SRC_TINT_RESOLVER_SEM_HELPER_H_

#include <string>

#include "src/tint/diagnostic/diagnostic.h"
#include "src/tint/program_builder.h"
#include "src/tint/resolver/dependency_graph.h"
#include "src/tint/utils/map.h"

namespace tint::resolver {

/// Helper class to retrieve sem information.
class SemHelper {
  public:
    /// Constructor
    /// @param builder the program builder
    explicit SemHelper(ProgramBuilder* builder);
    ~SemHelper();

    /// Get is a helper for obtaining the semantic node for the given AST node.
    /// Raises an ICE and returns `nullptr` if there is no semantic node associated with the AST
    /// node.
    /// @param ast the ast node to get the sem for
    /// @returns the sem node for @p ast
    template <typename SEM = sem::Info::InferFromAST, typename AST = ast::Node>
    auto* Get(const AST* ast) const {
        using T = sem::Info::GetResultType<SEM, AST>;
        auto* sem = builder_->Sem().Get(ast);
        if (TINT_UNLIKELY(!sem)) {
            TINT_ICE(Resolver, builder_->Diagnostics())
                << "AST node '" << ast->TypeInfo().name << "' had no semantic info\n"
                << "At: " << ast->source << "\n"
                << "Pointer: " << ast;
        }
        return const_cast<T*>(As<T>(sem));
    }

    /// GetVal is a helper for obtaining the semantic sem::ValueExpression for the given AST node.
    /// Raises an error diagnostic and returns `nullptr` if the semantic node is not a
    /// sem::ValueExpression.
    /// @param ast the ast node to get the sem for
    /// @returns the sem node for @p ast
    template <typename AST = ast::Node>
    auto* GetVal(const AST* ast) const {
        return AsValue(Get(ast));
    }

    /// @param expr the semantic node
    /// @returns one of:
    /// * nullptr if @p expr is nullptr
    /// * @p expr if the static pointer type already derives from sem::ValueExpression
    /// * @p expr cast to sem::ValueExpression if the cast is successful
    /// * nullptr if @p expr is not a sem::ValueExpression. In this case an error diagnostic is
    ///   raised.
    template <typename EXPR>
    auto* AsValue(EXPR* expr) const {
        if constexpr (traits::IsTypeOrDerived<EXPR, sem::ValueExpression>) {
            return expr;
        } else {
            if (TINT_LIKELY(expr)) {
                if (auto* val = expr->template As<sem::ValueExpression>(); TINT_LIKELY(val)) {
                    return val;
                }
                ErrorExpectedValueExpr(expr);
            }
            return static_cast<sem::ValueExpression*>(nullptr);
        }
    }

    /// @returns the resolved type of the ast::Expression @p expr
    /// @param expr the expression
    type::Type* TypeOf(const ast::Expression* expr) const;

    /// @returns the type name of the given semantic type, unwrapping references.
    /// @param ty the type to look up
    std::string TypeNameOf(const type::Type* ty) const;

    /// @returns the type name of the given semantic type, without unwrapping references.
    /// @param ty the type to look up
    std::string RawTypeNameOf(const type::Type* ty) const;

    /// Raises an error diagnostic that the expression @p got was expected to be a
    /// sem::ValueExpression, but the expression evaluated to something different.
    /// @param expr the expression
    void ErrorExpectedValueExpr(const sem::Expression* expr) const;

  private:
    /// Adds the given error message to the diagnostics
    void AddError(const std::string& msg, const Source& source) const;

    /// Adds the given warning message to the diagnostics
    void AddWarning(const std::string& msg, const Source& source) const;

    /// Adds the given note message to the diagnostics
    void AddNote(const std::string& msg, const Source& source) const;

    ProgramBuilder* builder_;
};

}  // namespace tint::resolver

#endif  // SRC_TINT_RESOLVER_SEM_HELPER_H_