clang-tools  6.0.0
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<std::pair<SourceLocation, SourceLocation>>;
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(Result.SourceManager->getImmediateExpansionRange(Loc));
51  Loc = Locs.back().first;
52  }
53  return Locs;
54 }
55 
56 } // namespace
57 
58 void MultipleStatementMacroCheck::registerMatchers(MatchFinder *Finder) {
59  const auto Inner = expr(isInMacro(), unless(compoundStmt())).bind("inner");
60  Finder->addMatcher(
61  stmt(anyOf(ifStmt(hasThen(Inner)), ifStmt(hasElse(Inner)).bind("else"),
62  whileStmt(hasBody(Inner)), forStmt(hasBody(Inner))))
63  .bind("outer"),
64  this);
65 }
66 
67 void MultipleStatementMacroCheck::check(
68  const MatchFinder::MatchResult &Result) {
69  const auto *Inner = Result.Nodes.getNodeAs<Expr>("inner");
70  const auto *Outer = Result.Nodes.getNodeAs<Stmt>("outer");
71  const auto *Next = nextStmt(Result, Outer);
72  if (!Next)
73  return;
74 
75  SourceLocation OuterLoc = Outer->getLocStart();
76  if (Result.Nodes.getNodeAs<Stmt>("else"))
77  OuterLoc = cast<IfStmt>(Outer)->getElseLoc();
78 
79  auto InnerRanges = getExpansionRanges(Inner->getLocStart(), Result);
80  auto OuterRanges = getExpansionRanges(OuterLoc, Result);
81  auto NextRanges = getExpansionRanges(Next->getLocStart(), Result);
82 
83  // Remove all the common ranges, starting from the top (the last ones in the
84  // list).
85  while (!InnerRanges.empty() && !OuterRanges.empty() && !NextRanges.empty() &&
86  InnerRanges.back() == OuterRanges.back() &&
87  InnerRanges.back() == NextRanges.back()) {
88  InnerRanges.pop_back();
89  OuterRanges.pop_back();
90  NextRanges.pop_back();
91  }
92 
93  // Inner and Next must have at least one more macro that Outer doesn't have,
94  // and that range must be common to both.
95  if (InnerRanges.empty() || NextRanges.empty() ||
96  InnerRanges.back() != NextRanges.back())
97  return;
98 
99  diag(InnerRanges.back().first, "multiple statement macro used without "
100  "braces; some statements will be "
101  "unconditionally executed");
102 }
103 
104 } // namespace bugprone
105 } // namespace tidy
106 } // namespace clang
SourceLocation Loc
&#39;#&#39; location in the include directive
AST_MATCHER(VarDecl, isAsm)