1 //===--- Transformer.cpp - Transformer library implementation ---*- 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 #include "clang/Tooling/Transformer/Transformer.h"
10 #include "clang/ASTMatchers/ASTMatchFinder.h"
11 #include "clang/ASTMatchers/ASTMatchersInternal.h"
12 #include "clang/Basic/SourceLocation.h"
13 #include "clang/Tooling/Refactoring/AtomicChange.h"
14 #include "llvm/Support/Error.h"
15 #include <map>
16 #include <utility>
17 #include <vector>
18 
19 using namespace clang;
20 using namespace tooling;
21 
22 using ast_matchers::MatchFinder;
23 
24 void Transformer::registerMatchers(MatchFinder *MatchFinder) {
25   for (auto &Matcher : transformer::detail::buildMatchers(Rule))
26     MatchFinder->addDynamicMatcher(Matcher, this);
27 }
28 
29 void Transformer::run(const MatchFinder::MatchResult &Result) {
30   if (Result.Context->getDiagnostics().hasErrorOccurred())
31     return;
32 
33   transformer::RewriteRule::Case Case =
34       transformer::detail::findSelectedCase(Result, Rule);
35   auto Transformations = Case.Edits(Result);
36   if (!Transformations) {
37     Consumer(Transformations.takeError());
38     return;
39   }
40 
41   if (Transformations->empty()) {
42     // No rewrite applied (but no error encountered either).
43     transformer::detail::getRuleMatchLoc(Result).print(
44         llvm::errs() << "note: skipping match at loc ", *Result.SourceManager);
45     llvm::errs() << "\n";
46     return;
47   }
48 
49   // Group the transformations, by file, into AtomicChanges, each anchored by
50   // the location of the first change in that file.
51   std::map<FileID, AtomicChange> ChangesByFileID;
52   for (const auto &T : *Transformations) {
53     auto ID = Result.SourceManager->getFileID(T.Range.getBegin());
54     auto Iter = ChangesByFileID
55                     .emplace(ID, AtomicChange(*Result.SourceManager,
56                                               T.Range.getBegin(), T.Metadata))
57                     .first;
58     auto &AC = Iter->second;
59     if (auto Err = AC.replace(*Result.SourceManager, T.Range, T.Replacement)) {
60       Consumer(std::move(Err));
61       return;
62     }
63   }
64 
65   for (auto &IDChangePair : ChangesByFileID) {
66     auto &AC = IDChangePair.second;
67     // FIXME: this will add includes to *all* changed files, which may not be
68     // the intent. We should upgrade the representation to allow associating
69     // headers with specific edits.
70     for (const auto &I : Case.AddedIncludes) {
71       auto &Header = I.first;
72       switch (I.second) {
73       case transformer::IncludeFormat::Quoted:
74         AC.addHeader(Header);
75         break;
76       case transformer::IncludeFormat::Angled:
77         AC.addHeader((llvm::Twine("<") + Header + ">").str());
78         break;
79       }
80     }
81 
82     Consumer(std::move(AC));
83   }
84 }
85