clang-tools  7.0.0
MultipleStatementMacroCheck.cpp
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1 //===--- MultipleStatementMacroCheck.cpp - clang-tidy----------------------===//
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 
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 
14 using namespace clang::ast_matchers;
15 
16 namespace clang {
17 namespace tidy {
18 namespace bugprone {
19 
20 namespace {
21 
22 AST_MATCHER(Expr, isInMacro) { return Node.getLocStart().isMacroID(); }
23 
24 /// \brief Find the next statement after `S`.
25 const Stmt *nextStmt(const MatchFinder::MatchResult &Result, const Stmt *S) {
26  auto Parents = Result.Context->getParents(*S);
27  if (Parents.empty())
28  return nullptr;
29  const auto *Parent = Parents[0].get<Stmt>();
30  if (!Parent)
31  return nullptr;
32  const Stmt *Prev = nullptr;
33  for (const Stmt *Child : Parent->children()) {
34  if (Prev == S)
35  return Child;
36  Prev = Child;
37  }
38  return nextStmt(Result, Parent);
39 }
40 
41 using ExpansionRanges = std::vector<SourceRange>;
42 
43 /// \bried Get all the macro expansion ranges related to `Loc`.
44 ///
45 /// The result is ordered from most inner to most outer.
46 ExpansionRanges getExpansionRanges(SourceLocation Loc,
47  const MatchFinder::MatchResult &Result) {
48  ExpansionRanges Locs;
49  while (Loc.isMacroID()) {
50  Locs.push_back(
51  Result.SourceManager->getImmediateExpansionRange(Loc).getAsRange());
52  Loc = Locs.back().getBegin();
53  }
54  return Locs;
55 }
56 
57 } // namespace
58 
59 void MultipleStatementMacroCheck::registerMatchers(MatchFinder *Finder) {
60  const auto Inner = expr(isInMacro(), unless(compoundStmt())).bind("inner");
61  Finder->addMatcher(
62  stmt(anyOf(ifStmt(hasThen(Inner)), ifStmt(hasElse(Inner)).bind("else"),
63  whileStmt(hasBody(Inner)), forStmt(hasBody(Inner))))
64  .bind("outer"),
65  this);
66 }
67 
68 void MultipleStatementMacroCheck::check(
69  const MatchFinder::MatchResult &Result) {
70  const auto *Inner = Result.Nodes.getNodeAs<Expr>("inner");
71  const auto *Outer = Result.Nodes.getNodeAs<Stmt>("outer");
72  const auto *Next = nextStmt(Result, Outer);
73  if (!Next)
74  return;
75 
76  SourceLocation OuterLoc = Outer->getLocStart();
77  if (Result.Nodes.getNodeAs<Stmt>("else"))
78  OuterLoc = cast<IfStmt>(Outer)->getElseLoc();
79 
80  auto InnerRanges = getExpansionRanges(Inner->getLocStart(), Result);
81  auto OuterRanges = getExpansionRanges(OuterLoc, Result);
82  auto NextRanges = getExpansionRanges(Next->getLocStart(), Result);
83 
84  // Remove all the common ranges, starting from the top (the last ones in the
85  // list).
86  while (!InnerRanges.empty() && !OuterRanges.empty() && !NextRanges.empty() &&
87  InnerRanges.back() == OuterRanges.back() &&
88  InnerRanges.back() == NextRanges.back()) {
89  InnerRanges.pop_back();
90  OuterRanges.pop_back();
91  NextRanges.pop_back();
92  }
93 
94  // Inner and Next must have at least one more macro that Outer doesn't have,
95  // and that range must be common to both.
96  if (InnerRanges.empty() || NextRanges.empty() ||
97  InnerRanges.back() != NextRanges.back())
98  return;
99 
100  diag(InnerRanges.back().getBegin(), "multiple statement macro used without "
101  "braces; some statements will be "
102  "unconditionally executed");
103 }
104 
105 } // namespace bugprone
106 } // namespace tidy
107 } // namespace clang
SourceLocation Loc
&#39;#&#39; location in the include directive
AST_MATCHER(BinaryOperator, isAssignmentOperator)
Definition: Matchers.h:20
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//