/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/Tooling/Transformer/MatchConsumer.h
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1 | | //===--- MatchConsumer.h - MatchConsumer abstraction ------------*- C++ -*-===// |
2 | | // |
3 | | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | | // See https://llvm.org/LICENSE.txt for license information. |
5 | | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | | // |
7 | | //===----------------------------------------------------------------------===// |
8 | | /// |
9 | | /// \file This file defines the *MatchConsumer* abstraction: a computation over |
10 | | /// match results, specifically the `ast_matchers::MatchFinder::MatchResult` |
11 | | /// class. |
12 | | /// |
13 | | //===----------------------------------------------------------------------===// |
14 | | |
15 | | #ifndef LLVM_CLANG_TOOLING_TRANSFORMER_MATCHCONSUMER_H |
16 | | #define LLVM_CLANG_TOOLING_TRANSFORMER_MATCHCONSUMER_H |
17 | | |
18 | | #include "clang/AST/ASTTypeTraits.h" |
19 | | #include "clang/ASTMatchers/ASTMatchFinder.h" |
20 | | #include "llvm/ADT/StringRef.h" |
21 | | #include "llvm/Support/Errc.h" |
22 | | #include "llvm/Support/Error.h" |
23 | | |
24 | | namespace clang { |
25 | | namespace transformer { |
26 | | /// A failable computation over nodes bound by AST matchers. |
27 | | /// |
28 | | /// The computation should report any errors though its return value (rather |
29 | | /// than terminating the program) to enable usage in interactive scenarios like |
30 | | /// clang-query. |
31 | | /// |
32 | | /// This is a central abstraction of the Transformer framework. |
33 | | template <typename T> |
34 | | using MatchConsumer = |
35 | | std::function<Expected<T>(const ast_matchers::MatchFinder::MatchResult &)>; |
36 | | |
37 | | /// Creates an error that signals that a `MatchConsumer` expected a certain node |
38 | | /// to be bound by AST matchers, but it was not actually bound. |
39 | 0 | inline llvm::Error notBoundError(llvm::StringRef Id) { |
40 | 0 | return llvm::make_error<llvm::StringError>(llvm::errc::invalid_argument, |
41 | 0 | "Id not bound: " + Id); |
42 | 0 | } |
43 | | |
44 | | /// Chooses between the two consumers, based on whether \p ID is bound in the |
45 | | /// match. |
46 | | template <typename T> |
47 | | MatchConsumer<T> ifBound(std::string ID, MatchConsumer<T> TrueC, |
48 | | MatchConsumer<T> FalseC) { |
49 | | return [=](const ast_matchers::MatchFinder::MatchResult &Result) { |
50 | | auto &Map = Result.Nodes.getMap(); |
51 | | return (Map.find(ID) != Map.end() ? TrueC : FalseC)(Result); |
52 | | }; |
53 | | } |
54 | | |
55 | | /// A failable computation over nodes bound by AST matchers, with (limited) |
56 | | /// reflection via the `toString` method. |
57 | | /// |
58 | | /// The computation should report any errors though its return value (rather |
59 | | /// than terminating the program) to enable usage in interactive scenarios like |
60 | | /// clang-query. |
61 | | /// |
62 | | /// This is a central abstraction of the Transformer framework. It is a |
63 | | /// generalization of `MatchConsumer` and intended to replace it. |
64 | | template <typename T> class MatchComputation { |
65 | | public: |
66 | 262 | virtual ~MatchComputation() = default; |
67 | | |
68 | | /// Evaluates the computation and (potentially) updates the accumulator \c |
69 | | /// Result. \c Result is undefined in the case of an error. `Result` is an |
70 | | /// out parameter to optimize case where the computation involves composing |
71 | | /// the result of sub-computation evaluations. |
72 | | virtual llvm::Error eval(const ast_matchers::MatchFinder::MatchResult &Match, |
73 | | T *Result) const = 0; |
74 | | |
75 | | /// Convenience version of `eval`, for the case where the computation is being |
76 | | /// evaluated on its own. |
77 | | llvm::Expected<T> eval(const ast_matchers::MatchFinder::MatchResult &R) const; |
78 | | |
79 | | /// Constructs a string representation of the computation, for informational |
80 | | /// purposes. The representation must be deterministic, but is not required to |
81 | | /// be unique. |
82 | | virtual std::string toString() const = 0; |
83 | | |
84 | | protected: |
85 | 262 | MatchComputation() = default; |
86 | | |
87 | | // Since this is an abstract class, copying/assigning only make sense for |
88 | | // derived classes implementing `clone()`. |
89 | | MatchComputation(const MatchComputation &) = default; |
90 | | MatchComputation &operator=(const MatchComputation &) = default; |
91 | | }; |
92 | | |
93 | | template <typename T> |
94 | | llvm::Expected<T> MatchComputation<T>::eval( |
95 | 191 | const ast_matchers::MatchFinder::MatchResult &R) const { |
96 | 191 | T Output; |
97 | 191 | if (auto Err = eval(R, &Output)) |
98 | 8 | return std::move(Err); |
99 | 183 | return Output; |
100 | 191 | } |
101 | | } // namespace transformer |
102 | | } // namespace clang |
103 | | #endif // LLVM_CLANG_TOOLING_TRANSFORMER_MATCHCONSUMER_H |