clang  9.0.0
SourceExtraction.cpp
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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 "SourceExtraction.h"
10 #include "clang/AST/Stmt.h"
11 #include "clang/AST/StmtCXX.h"
12 #include "clang/AST/StmtObjC.h"
14 #include "clang/Lex/Lexer.h"
15 
16 using namespace clang;
17 
18 namespace {
19 
20 /// Returns true if the token at the given location is a semicolon.
21 bool isSemicolonAtLocation(SourceLocation TokenLoc, const SourceManager &SM,
22  const LangOptions &LangOpts) {
23  return Lexer::getSourceText(
24  CharSourceRange::getTokenRange(TokenLoc, TokenLoc), SM,
25  LangOpts) == ";";
26 }
27 
28 /// Returns true if there should be a semicolon after the given statement.
29 bool isSemicolonRequiredAfter(const Stmt *S) {
30  if (isa<CompoundStmt>(S))
31  return false;
32  if (const auto *If = dyn_cast<IfStmt>(S))
33  return isSemicolonRequiredAfter(If->getElse() ? If->getElse()
34  : If->getThen());
35  if (const auto *While = dyn_cast<WhileStmt>(S))
36  return isSemicolonRequiredAfter(While->getBody());
37  if (const auto *For = dyn_cast<ForStmt>(S))
38  return isSemicolonRequiredAfter(For->getBody());
39  if (const auto *CXXFor = dyn_cast<CXXForRangeStmt>(S))
40  return isSemicolonRequiredAfter(CXXFor->getBody());
41  if (const auto *ObjCFor = dyn_cast<ObjCForCollectionStmt>(S))
42  return isSemicolonRequiredAfter(ObjCFor->getBody());
43  switch (S->getStmtClass()) {
44  case Stmt::SwitchStmtClass:
45  case Stmt::CXXTryStmtClass:
46  case Stmt::ObjCAtSynchronizedStmtClass:
47  case Stmt::ObjCAutoreleasePoolStmtClass:
48  case Stmt::ObjCAtTryStmtClass:
49  return false;
50  default:
51  return true;
52  }
53 }
54 
55 /// Returns true if the two source locations are on the same line.
56 bool areOnSameLine(SourceLocation Loc1, SourceLocation Loc2,
57  const SourceManager &SM) {
58  return !Loc1.isMacroID() && !Loc2.isMacroID() &&
59  SM.getSpellingLineNumber(Loc1) == SM.getSpellingLineNumber(Loc2);
60 }
61 
62 } // end anonymous namespace
63 
64 namespace clang {
65 namespace tooling {
66 
67 ExtractionSemicolonPolicy
69  const SourceManager &SM,
70  const LangOptions &LangOpts) {
71  auto neededInExtractedFunction = []() {
72  return ExtractionSemicolonPolicy(true, false);
73  };
74  auto neededInOriginalFunction = []() {
75  return ExtractionSemicolonPolicy(false, true);
76  };
77 
78  /// The extracted expression should be terminated with a ';'. The call to
79  /// the extracted function will replace this expression, so it won't need
80  /// a terminating ';'.
81  if (isa<Expr>(S))
82  return neededInExtractedFunction();
83 
84  /// Some statements don't need to be terminated with ';'. The call to the
85  /// extracted function will be a standalone statement, so it should be
86  /// terminated with a ';'.
87  bool NeedsSemi = isSemicolonRequiredAfter(S);
88  if (!NeedsSemi)
89  return neededInOriginalFunction();
90 
91  /// Some statements might end at ';'. The extraction will move that ';', so
92  /// the call to the extracted function should be terminated with a ';'.
93  SourceLocation End = ExtractedRange.getEnd();
94  if (isSemicolonAtLocation(End, SM, LangOpts))
95  return neededInOriginalFunction();
96 
97  /// Other statements should generally have a trailing ';'. We can try to find
98  /// it and move it together it with the extracted code.
99  Optional<Token> NextToken = Lexer::findNextToken(End, SM, LangOpts);
100  if (NextToken && NextToken->is(tok::semi) &&
101  areOnSameLine(NextToken->getLocation(), End, SM)) {
102  ExtractedRange.setEnd(NextToken->getLocation());
103  return neededInOriginalFunction();
104  }
105 
106  /// Otherwise insert semicolons in both places.
107  return ExtractionSemicolonPolicy(true, true);
108 }
109 
110 } // end namespace tooling
111 } // end namespace clang
Stmt - This represents one statement.
Definition: Stmt.h:66
Defines the SourceManager interface.
static CharSourceRange getTokenRange(SourceRange R)
Defines the Objective-C statement AST node classes.
Determines which semicolons should be inserted during extraction.
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:49
unsigned getSpellingLineNumber(SourceLocation Loc, bool *Invalid=nullptr) const
static StringRef getSourceText(CharSourceRange Range, const SourceManager &SM, const LangOptions &LangOpts, bool *Invalid=nullptr)
Returns a string for the source that the range encompasses.
Definition: Lexer.cpp:930
SourceLocation End
SourceLocation getEnd() const
const SourceManager & SM
Definition: Format.cpp:1572
Encodes a location in the source.
static Optional< Token > findNextToken(SourceLocation Loc, const SourceManager &SM, const LangOptions &LangOpts)
Finds the token that comes right after the given location.
Definition: Lexer.cpp:1228
static ExtractionSemicolonPolicy compute(const Stmt *S, SourceRange &ExtractedRange, const SourceManager &SM, const LangOptions &LangOpts)
Returns the semicolon insertion policy that is needed for extraction of the given statement from the ...
Dataflow Directional Tag Classes.
StmtClass getStmtClass() const
Definition: Stmt.h:1087
bool isMacroID() const
void setEnd(SourceLocation e)
A trivial tuple used to represent a source range.
This class handles loading and caching of source files into memory.