clang-tools  5.0.0
ProTypeVarargCheck.cpp
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1 //===--- ProTypeVarargCheck.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 
10 #include "ProTypeVarargCheck.h"
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 cppcoreguidelines {
19 
20 const internal::VariadicDynCastAllOfMatcher<Stmt, VAArgExpr> vAArgExpr;
21 
22 void ProTypeVarargCheck::registerMatchers(MatchFinder *Finder) {
23  if (!getLangOpts().CPlusPlus)
24  return;
25 
26  Finder->addMatcher(vAArgExpr().bind("va_use"), this);
27 
28  Finder->addMatcher(
29  callExpr(callee(functionDecl(isVariadic()))).bind("callvararg"), this);
30 }
31 
32 static bool hasSingleVariadicArgumentWithValue(const CallExpr *C, uint64_t I) {
33  const auto *FDecl = dyn_cast<FunctionDecl>(C->getCalleeDecl());
34  if (!FDecl)
35  return false;
36 
37  auto N = FDecl->getNumParams(); // Number of parameters without '...'
38  if (C->getNumArgs() != N + 1)
39  return false; // more/less than one argument passed to '...'
40 
41  const auto *IntLit =
42  dyn_cast<IntegerLiteral>(C->getArg(N)->IgnoreParenImpCasts());
43  if (!IntLit)
44  return false;
45 
46  if (IntLit->getValue() != I)
47  return false;
48 
49  return true;
50 }
51 
52 void ProTypeVarargCheck::check(const MatchFinder::MatchResult &Result) {
53  if (const auto *Matched = Result.Nodes.getNodeAs<CallExpr>("callvararg")) {
54  if (hasSingleVariadicArgumentWithValue(Matched, 0))
55  return;
56  diag(Matched->getExprLoc(), "do not call c-style vararg functions");
57  }
58 
59  if (const auto *Matched = Result.Nodes.getNodeAs<Expr>("va_use")) {
60  diag(Matched->getExprLoc(),
61  "do not use va_start/va_arg to define c-style vararg functions; "
62  "use variadic templates instead");
63  }
64 
65  if (const auto *Matched = Result.Nodes.getNodeAs<VarDecl>("va_list")) {
66  auto SR = Matched->getSourceRange();
67  if (SR.isInvalid())
68  return; // some implicitly generated builtins take va_list
69  diag(SR.getBegin(), "do not declare variables of type va_list; "
70  "use variadic templates instead");
71  }
72 }
73 
74 } // namespace cppcoreguidelines
75 } // namespace tidy
76 } // namespace clang
std::unique_ptr< ast_matchers::MatchFinder > Finder
Definition: ClangTidy.cpp:275
const internal::VariadicDynCastAllOfMatcher< Stmt, VAArgExpr > vAArgExpr
static bool hasSingleVariadicArgumentWithValue(const CallExpr *C, uint64_t I)