clang  6.0.0svn
SourceExtraction.cpp
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1 //===--- SourceExtraction.cpp - Clang refactoring library -----------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "SourceExtraction.h"
11 #include "clang/AST/Stmt.h"
12 #include "clang/AST/StmtCXX.h"
13 #include "clang/AST/StmtObjC.h"
15 #include "clang/Lex/Lexer.h"
16 
17 using namespace clang;
18 
19 namespace {
20 
21 /// Returns true if the token at the given location is a semicolon.
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.
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  switch (S->getStmtClass()) {
45  case Stmt::SwitchStmtClass:
46  case Stmt::CXXTryStmtClass:
47  case Stmt::ObjCAtSynchronizedStmtClass:
48  case Stmt::ObjCAutoreleasePoolStmtClass:
49  case Stmt::ObjCAtTryStmtClass:
50  return false;
51  default:
52  return true;
53  }
54 }
55 
56 /// Returns true if the two source locations are on the same line.
57 bool areOnSameLine(SourceLocation Loc1, SourceLocation Loc2,
58  const SourceManager &SM) {
59  return !Loc1.isMacroID() && !Loc2.isMacroID() &&
60  SM.getSpellingLineNumber(Loc1) == SM.getSpellingLineNumber(Loc2);
61 }
62 
63 } // end anonymous namespace
64 
65 namespace clang {
66 namespace tooling {
67 
68 ExtractionSemicolonPolicy
70  const SourceManager &SM,
71  const LangOptions &LangOpts) {
72  auto neededInExtractedFunction = []() {
73  return ExtractionSemicolonPolicy(true, false);
74  };
75  auto neededInOriginalFunction = []() {
76  return ExtractionSemicolonPolicy(false, true);
77  };
78 
79  /// The extracted expression should be terminated with a ';'. The call to
80  /// the extracted function will replace this expression, so it won't need
81  /// a terminating ';'.
82  if (isa<Expr>(S))
83  return neededInExtractedFunction();
84 
85  /// Some statements don't need to be terminated with ';'. The call to the
86  /// extracted function will be a standalone statement, so it should be
87  /// terminated with a ';'.
88  bool NeedsSemi = isSemicolonRequiredAfter(S);
89  if (!NeedsSemi)
90  return neededInOriginalFunction();
91 
92  /// Some statements might end at ';'. The extraction will move that ';', so
93  /// the call to the extracted function should be terminated with a ';'.
94  SourceLocation End = ExtractedRange.getEnd();
95  if (isSemicolonAtLocation(End, SM, LangOpts))
96  return neededInOriginalFunction();
97 
98  /// Other statements should generally have a trailing ';'. We can try to find
99  /// it and move it together it with the extracted code.
100  Optional<Token> NextToken = Lexer::findNextToken(End, SM, LangOpts);
101  if (NextToken && NextToken->is(tok::semi) &&
102  areOnSameLine(NextToken->getLocation(), End, SM)) {
103  ExtractedRange.setEnd(NextToken->getLocation());
104  return neededInOriginalFunction();
105  }
106 
107  /// Otherwise insert semicolons in both places.
108  return ExtractionSemicolonPolicy(true, true);
109 }
110 
111 } // end namespace tooling
112 } // 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:48
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:935
SourceLocation End
SourceLocation getEnd() const
const SourceManager & SM
Definition: Format.cpp:1337
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:1234
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:378
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.