clang-tools  6.0.0
MisplacedOperatorInStrlenInAllocCheck.cpp
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1 //===--- MisplacedOperatorInStrlenInAllocCheck.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 void MisplacedOperatorInStrlenInAllocCheck::registerMatchers(
21  MatchFinder *Finder) {
22  const auto StrLenFunc = functionDecl(anyOf(
23  hasName("::strlen"), hasName("::std::strlen"), hasName("::strnlen"),
24  hasName("::std::strnlen"), hasName("::strnlen_s"),
25  hasName("::std::strnlen_s"), hasName("::wcslen"),
26  hasName("::std::wcslen"), hasName("::wcsnlen"), hasName("::std::wcsnlen"),
27  hasName("::wcsnlen_s"), hasName("std::wcsnlen_s")));
28 
29  const auto BadUse =
30  callExpr(callee(StrLenFunc),
31  hasAnyArgument(ignoringImpCasts(
32  binaryOperator(allOf(hasOperatorName("+"),
33  hasRHS(ignoringParenImpCasts(
34  integerLiteral(equals(1))))))
35  .bind("BinOp"))))
36  .bind("StrLen");
37 
38  const auto BadArg = anyOf(
39  allOf(hasDescendant(BadUse),
40  unless(binaryOperator(allOf(
41  hasOperatorName("+"), hasLHS(BadUse),
42  hasRHS(ignoringParenImpCasts(integerLiteral(equals(1)))))))),
43  BadUse);
44 
45  const auto Alloc0Func =
46  functionDecl(anyOf(hasName("::malloc"), hasName("std::malloc"),
47  hasName("::alloca"), hasName("std::alloca")));
48  const auto Alloc1Func =
49  functionDecl(anyOf(hasName("::calloc"), hasName("std::calloc"),
50  hasName("::realloc"), hasName("std::realloc")));
51 
52  const auto Alloc0FuncPtr =
53  varDecl(hasType(isConstQualified()),
54  hasInitializer(ignoringParenImpCasts(
55  declRefExpr(hasDeclaration(Alloc0Func)))));
56  const auto Alloc1FuncPtr =
57  varDecl(hasType(isConstQualified()),
58  hasInitializer(ignoringParenImpCasts(
59  declRefExpr(hasDeclaration(Alloc1Func)))));
60 
61  Finder->addMatcher(callExpr(callee(decl(anyOf(Alloc0Func, Alloc0FuncPtr))),
62  hasArgument(0, BadArg))
63  .bind("Alloc"),
64  this);
65  Finder->addMatcher(callExpr(callee(decl(anyOf(Alloc1Func, Alloc1FuncPtr))),
66  hasArgument(1, BadArg))
67  .bind("Alloc"),
68  this);
69  Finder->addMatcher(
70  cxxNewExpr(isArray(), hasArraySize(BadArg)).bind("Alloc"), this);
71 }
72 
73 void MisplacedOperatorInStrlenInAllocCheck::check(
74  const MatchFinder::MatchResult &Result) {
75  const Expr *Alloc = Result.Nodes.getNodeAs<CallExpr>("Alloc");
76  if (!Alloc)
77  Alloc = Result.Nodes.getNodeAs<CXXNewExpr>("Alloc");
78  assert(Alloc && "Matched node bound by 'Alloc' shoud be either 'CallExpr'"
79  " or 'CXXNewExpr'");
80 
81  const auto *StrLen = Result.Nodes.getNodeAs<CallExpr>("StrLen");
82  const auto *BinOp = Result.Nodes.getNodeAs<BinaryOperator>("BinOp");
83 
84  const StringRef StrLenText = Lexer::getSourceText(
85  CharSourceRange::getTokenRange(StrLen->getSourceRange()),
86  *Result.SourceManager, getLangOpts());
87  const StringRef Arg0Text = Lexer::getSourceText(
88  CharSourceRange::getTokenRange(StrLen->getArg(0)->getSourceRange()),
89  *Result.SourceManager, getLangOpts());
90  const StringRef StrLenBegin = StrLenText.substr(0, StrLenText.find(Arg0Text));
91  const StringRef StrLenEnd = StrLenText.substr(
92  StrLenText.find(Arg0Text) + Arg0Text.size(), StrLenText.size());
93 
94  const StringRef LHSText = Lexer::getSourceText(
95  CharSourceRange::getTokenRange(BinOp->getLHS()->getSourceRange()),
96  *Result.SourceManager, getLangOpts());
97  const StringRef RHSText = Lexer::getSourceText(
98  CharSourceRange::getTokenRange(BinOp->getRHS()->getSourceRange()),
99  *Result.SourceManager, getLangOpts());
100 
101  auto Hint = FixItHint::CreateReplacement(
102  StrLen->getSourceRange(),
103  (StrLenBegin + LHSText + StrLenEnd + " + " + RHSText).str());
104 
105  diag(Alloc->getLocStart(),
106  "addition operator is applied to the argument of %0 instead of its "
107  "result") << StrLen->getDirectCallee()->getName() << Hint;
108 }
109 
110 } // namespace bugprone
111 } // namespace tidy
112 } // namespace clang