1 //===--- SourceExtraction.cpp - Clang refactoring library -----------------===//
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/Refactoring/Extract/SourceExtraction.h"
10 #include "clang/AST/Stmt.h"
11 #include "clang/AST/StmtCXX.h"
12 #include "clang/AST/StmtObjC.h"
13 #include "clang/Basic/SourceManager.h"
14 #include "clang/Lex/Lexer.h"
15 #include <optional>
16
17 using namespace clang;
18
19 namespace {
20
21 /// Returns true if the token at the given location is a semicolon.
isSemicolonAtLocation(SourceLocation TokenLoc,const SourceManager & SM,const LangOptions & LangOpts)22 bool isSemicolonAtLocation(SourceLocation TokenLoc, const SourceManager &SM,
23 const LangOptions &LangOpts) {
24 return Lexer::getSourceText(
25 CharSourceRange::getTokenRange(TokenLoc, TokenLoc), SM,
26 LangOpts) == ";";
27 }
28
29 /// Returns true if there should be a semicolon after the given statement.
isSemicolonRequiredAfter(const Stmt * S)30 bool isSemicolonRequiredAfter(const Stmt *S) {
31 if (isa<CompoundStmt>(S))
32 return false;
33 if (const auto *If = dyn_cast<IfStmt>(S))
34 return isSemicolonRequiredAfter(If->getElse() ? If->getElse()
35 : If->getThen());
36 if (const auto *While = dyn_cast<WhileStmt>(S))
37 return isSemicolonRequiredAfter(While->getBody());
38 if (const auto *For = dyn_cast<ForStmt>(S))
39 return isSemicolonRequiredAfter(For->getBody());
40 if (const auto *CXXFor = dyn_cast<CXXForRangeStmt>(S))
41 return isSemicolonRequiredAfter(CXXFor->getBody());
42 if (const auto *ObjCFor = dyn_cast<ObjCForCollectionStmt>(S))
43 return isSemicolonRequiredAfter(ObjCFor->getBody());
44 if(const auto *Switch = dyn_cast<SwitchStmt>(S))
45 return isSemicolonRequiredAfter(Switch->getBody());
46 if(const auto *Case = dyn_cast<SwitchCase>(S))
47 return isSemicolonRequiredAfter(Case->getSubStmt());
48 switch (S->getStmtClass()) {
49 case Stmt::DeclStmtClass:
50 case Stmt::CXXTryStmtClass:
51 case Stmt::ObjCAtSynchronizedStmtClass:
52 case Stmt::ObjCAutoreleasePoolStmtClass:
53 case Stmt::ObjCAtTryStmtClass:
54 return false;
55 default:
56 return true;
57 }
58 }
59
60 /// Returns true if the two source locations are on the same line.
areOnSameLine(SourceLocation Loc1,SourceLocation Loc2,const SourceManager & SM)61 bool areOnSameLine(SourceLocation Loc1, SourceLocation Loc2,
62 const SourceManager &SM) {
63 return !Loc1.isMacroID() && !Loc2.isMacroID() &&
64 SM.getSpellingLineNumber(Loc1) == SM.getSpellingLineNumber(Loc2);
65 }
66
67 } // end anonymous namespace
68
69 namespace clang {
70 namespace tooling {
71
72 ExtractionSemicolonPolicy
compute(const Stmt * S,SourceRange & ExtractedRange,const SourceManager & SM,const LangOptions & LangOpts)73 ExtractionSemicolonPolicy::compute(const Stmt *S, SourceRange &ExtractedRange,
74 const SourceManager &SM,
75 const LangOptions &LangOpts) {
76 auto neededInExtractedFunction = []() {
77 return ExtractionSemicolonPolicy(true, false);
78 };
79 auto neededInOriginalFunction = []() {
80 return ExtractionSemicolonPolicy(false, true);
81 };
82
83 /// The extracted expression should be terminated with a ';'. The call to
84 /// the extracted function will replace this expression, so it won't need
85 /// a terminating ';'.
86 if (isa<Expr>(S))
87 return neededInExtractedFunction();
88
89 /// Some statements don't need to be terminated with ';'. The call to the
90 /// extracted function will be a standalone statement, so it should be
91 /// terminated with a ';'.
92 bool NeedsSemi = isSemicolonRequiredAfter(S);
93 if (!NeedsSemi)
94 return neededInOriginalFunction();
95
96 /// Some statements might end at ';'. The extraction will move that ';', so
97 /// the call to the extracted function should be terminated with a ';'.
98 SourceLocation End = ExtractedRange.getEnd();
99 if (isSemicolonAtLocation(End, SM, LangOpts))
100 return neededInOriginalFunction();
101
102 /// Other statements should generally have a trailing ';'. We can try to find
103 /// it and move it together it with the extracted code.
104 std::optional<Token> NextToken = Lexer::findNextToken(End, SM, LangOpts);
105 if (NextToken && NextToken->is(tok::semi) &&
106 areOnSameLine(NextToken->getLocation(), End, SM)) {
107 ExtractedRange.setEnd(NextToken->getLocation());
108 return neededInOriginalFunction();
109 }
110
111 /// Otherwise insert semicolons in both places.
112 return ExtractionSemicolonPolicy(true, true);
113 }
114
115 } // end namespace tooling
116 } // end namespace clang
117