| //===--- MatchConsumer.h - MatchConsumer abstraction ------------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| /// |
| /// \file This file defines the *MatchConsumer* abstraction: a computation over |
| /// match results, specifically the `ast_matchers::MatchFinder::MatchResult` |
| /// class. |
| /// |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CLANG_TOOLING_TRANSFORMER_MATCH_CONSUMER_H_ |
| #define LLVM_CLANG_TOOLING_TRANSFORMER_MATCH_CONSUMER_H_ |
| |
| #include "clang/AST/ASTTypeTraits.h" |
| #include "clang/ASTMatchers/ASTMatchFinder.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/Support/Errc.h" |
| #include "llvm/Support/Error.h" |
| |
| namespace clang { |
| namespace transformer { |
| /// A failable computation over nodes bound by AST matchers. |
| /// |
| /// The computation should report any errors though its return value (rather |
| /// than terminating the program) to enable usage in interactive scenarios like |
| /// clang-query. |
| /// |
| /// This is a central abstraction of the Transformer framework. |
| template <typename T> |
| using MatchConsumer = |
| std::function<Expected<T>(const ast_matchers::MatchFinder::MatchResult &)>; |
| |
| /// Creates an error that signals that a `MatchConsumer` expected a certain node |
| /// to be bound by AST matchers, but it was not actually bound. |
| inline llvm::Error notBoundError(llvm::StringRef Id) { |
| return llvm::make_error<llvm::StringError>(llvm::errc::invalid_argument, |
| "Id not bound: " + Id); |
| } |
| |
| /// Chooses between the two consumers, based on whether \p ID is bound in the |
| /// match. |
| template <typename T> |
| MatchConsumer<T> ifBound(std::string ID, MatchConsumer<T> TrueC, |
| MatchConsumer<T> FalseC) { |
| return [=](const ast_matchers::MatchFinder::MatchResult &Result) { |
| auto &Map = Result.Nodes.getMap(); |
| return (Map.find(ID) != Map.end() ? TrueC : FalseC)(Result); |
| }; |
| } |
| |
| /// A failable computation over nodes bound by AST matchers, with (limited) |
| /// reflection via the `toString` method. |
| /// |
| /// The computation should report any errors though its return value (rather |
| /// than terminating the program) to enable usage in interactive scenarios like |
| /// clang-query. |
| /// |
| /// This is a central abstraction of the Transformer framework. It is a |
| /// generalization of `MatchConsumer` and intended to replace it. |
| template <typename T> class MatchComputation { |
| public: |
| virtual ~MatchComputation() = default; |
| |
| /// Evaluates the computation and (potentially) updates the accumulator \c |
| /// Result. \c Result is undefined in the case of an error. `Result` is an |
| /// out parameter to optimize case where the computation involves composing |
| /// the result of sub-computation evaluations. |
| virtual llvm::Error eval(const ast_matchers::MatchFinder::MatchResult &Match, |
| T *Result) const = 0; |
| |
| /// Convenience version of `eval`, for the case where the computation is being |
| /// evaluated on its own. |
| llvm::Expected<T> eval(const ast_matchers::MatchFinder::MatchResult &R) const; |
| |
| /// Constructs a string representation of the computation, for informational |
| /// purposes. The representation must be deterministic, but is not required to |
| /// be unique. |
| virtual std::string toString() const = 0; |
| |
| protected: |
| MatchComputation() = default; |
| |
| // Since this is an abstract class, copying/assigning only make sense for |
| // derived classes implementing `clone()`. |
| MatchComputation(const MatchComputation &) = default; |
| MatchComputation &operator=(const MatchComputation &) = default; |
| }; |
| |
| template <typename T> |
| llvm::Expected<T> MatchComputation<T>::eval( |
| const ast_matchers::MatchFinder::MatchResult &R) const { |
| T Output; |
| if (auto Err = eval(R, &Output)) |
| return std::move(Err); |
| return Output; |
| } |
| } // namespace transformer |
| } // namespace clang |
| #endif // LLVM_CLANG_TOOLING_TRANSFORMER_MATCH_CONSUMER_H_ |