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| Rev | Author | Line No. | Line |
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| 14 | pmbaty | 1 | //===--- MatchConsumer.h - MatchConsumer abstraction ------------*- C++ -*-===// |
| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | /// |
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| 9 | /// \file This file defines the *MatchConsumer* abstraction: a computation over |
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| 10 | /// match results, specifically the `ast_matchers::MatchFinder::MatchResult` |
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| 11 | /// class. |
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| 12 | /// |
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| 13 | //===----------------------------------------------------------------------===// |
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| 14 | |||
| 15 | #ifndef LLVM_CLANG_TOOLING_TRANSFORMER_MATCHCONSUMER_H |
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| 16 | #define LLVM_CLANG_TOOLING_TRANSFORMER_MATCHCONSUMER_H |
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| 17 | |||
| 18 | #include "clang/AST/ASTTypeTraits.h" |
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| 19 | #include "clang/ASTMatchers/ASTMatchFinder.h" |
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| 20 | #include "llvm/ADT/StringRef.h" |
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| 21 | #include "llvm/Support/Errc.h" |
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| 22 | #include "llvm/Support/Error.h" |
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| 23 | |||
| 24 | namespace clang { |
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| 25 | namespace transformer { |
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| 26 | /// A failable computation over nodes bound by AST matchers. |
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| 27 | /// |
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| 28 | /// The computation should report any errors though its return value (rather |
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| 29 | /// than terminating the program) to enable usage in interactive scenarios like |
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| 30 | /// clang-query. |
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| 31 | /// |
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| 32 | /// This is a central abstraction of the Transformer framework. |
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| 33 | template <typename T> |
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| 34 | using MatchConsumer = |
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| 35 | std::function<Expected<T>(const ast_matchers::MatchFinder::MatchResult &)>; |
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| 36 | |||
| 37 | /// Creates an error that signals that a `MatchConsumer` expected a certain node |
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| 38 | /// to be bound by AST matchers, but it was not actually bound. |
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| 39 | inline llvm::Error notBoundError(llvm::StringRef Id) { |
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| 40 | return llvm::make_error<llvm::StringError>(llvm::errc::invalid_argument, |
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| 41 | "Id not bound: " + Id); |
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| 42 | } |
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| 43 | |||
| 44 | /// Chooses between the two consumers, based on whether \p ID is bound in the |
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| 45 | /// match. |
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| 46 | template <typename T> |
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| 47 | MatchConsumer<T> ifBound(std::string ID, MatchConsumer<T> TrueC, |
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| 48 | MatchConsumer<T> FalseC) { |
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| 49 | return [=](const ast_matchers::MatchFinder::MatchResult &Result) { |
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| 50 | auto &Map = Result.Nodes.getMap(); |
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| 51 | return (Map.find(ID) != Map.end() ? TrueC : FalseC)(Result); |
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| 52 | }; |
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| 53 | } |
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| 54 | |||
| 55 | /// A failable computation over nodes bound by AST matchers, with (limited) |
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| 56 | /// reflection via the `toString` method. |
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| 57 | /// |
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| 58 | /// The computation should report any errors though its return value (rather |
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| 59 | /// than terminating the program) to enable usage in interactive scenarios like |
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| 60 | /// clang-query. |
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| 61 | /// |
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| 62 | /// This is a central abstraction of the Transformer framework. It is a |
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| 63 | /// generalization of `MatchConsumer` and intended to replace it. |
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| 64 | template <typename T> class MatchComputation { |
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| 65 | public: |
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| 66 | virtual ~MatchComputation() = default; |
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| 67 | |||
| 68 | /// Evaluates the computation and (potentially) updates the accumulator \c |
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| 69 | /// Result. \c Result is undefined in the case of an error. `Result` is an |
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| 70 | /// out parameter to optimize case where the computation involves composing |
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| 71 | /// the result of sub-computation evaluations. |
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| 72 | virtual llvm::Error eval(const ast_matchers::MatchFinder::MatchResult &Match, |
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| 73 | T *Result) const = 0; |
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| 74 | |||
| 75 | /// Convenience version of `eval`, for the case where the computation is being |
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| 76 | /// evaluated on its own. |
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| 77 | llvm::Expected<T> eval(const ast_matchers::MatchFinder::MatchResult &R) const; |
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| 78 | |||
| 79 | /// Constructs a string representation of the computation, for informational |
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| 80 | /// purposes. The representation must be deterministic, but is not required to |
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| 81 | /// be unique. |
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| 82 | virtual std::string toString() const = 0; |
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| 83 | |||
| 84 | protected: |
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| 85 | MatchComputation() = default; |
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| 86 | |||
| 87 | // Since this is an abstract class, copying/assigning only make sense for |
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| 88 | // derived classes implementing `clone()`. |
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| 89 | MatchComputation(const MatchComputation &) = default; |
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| 90 | MatchComputation &operator=(const MatchComputation &) = default; |
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| 91 | }; |
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| 92 | |||
| 93 | template <typename T> |
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| 94 | llvm::Expected<T> MatchComputation<T>::eval( |
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| 95 | const ast_matchers::MatchFinder::MatchResult &R) const { |
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| 96 | T Output; |
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| 97 | if (auto Err = eval(R, &Output)) |
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| 98 | return std::move(Err); |
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| 99 | return Output; |
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| 100 | } |
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| 101 | } // namespace transformer |
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| 102 | } // namespace clang |
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| 103 | #endif // LLVM_CLANG_TOOLING_TRANSFORMER_MATCHCONSUMER_H |