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
17using namespace clang;
18
19namespace {
20
21/// Returns true if the token at the given location is a semicolon.
22bool 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.
30bool 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.
61bool 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
69namespace clang {
70namespace tooling {
71
72ExtractionSemicolonPolicy
73ExtractionSemicolonPolicy::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