1 //===--- NonConstParameterCheck.h - clang-tidy-------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_NON_CONST_PARAMETER_H
10 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_NON_CONST_PARAMETER_H
11 
12 #include "../ClangTidyCheck.h"
13 
14 namespace clang::tidy::readability {
15 
16 /// Warn when a pointer function parameter can be const.
17 ///
18 /// For the user-facing documentation see:
19 /// http://clang.llvm.org/extra/clang-tidy/checks/readability/non-const-parameter.html
20 class NonConstParameterCheck : public ClangTidyCheck {
21 public:
NonConstParameterCheck(StringRef Name,ClangTidyContext * Context)22   NonConstParameterCheck(StringRef Name, ClangTidyContext *Context)
23       : ClangTidyCheck(Name, Context) {}
24   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
25   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
26   void onEndOfTranslationUnit() override;
getCheckTraversalKind()27   std::optional<TraversalKind> getCheckTraversalKind() const override {
28     return TK_IgnoreUnlessSpelledInSource;
29   }
30 
31 private:
32   /// Parameter info.
33   struct ParmInfo {
34     /// Is function parameter referenced?
35     bool IsReferenced;
36 
37     /// Can function parameter be const?
38     bool CanBeConst;
39   };
40 
41   /// Track all nonconst integer/float parameters.
42   std::map<const ParmVarDecl *, ParmInfo> Parameters;
43 
44   /// Add function parameter.
45   void addParm(const ParmVarDecl *Parm);
46 
47   /// Set IsReferenced.
48   void setReferenced(const DeclRefExpr *Ref);
49 
50   /// Set CanNotBeConst.
51   /// Visits sub expressions recursively. If a DeclRefExpr is found
52   /// and CanNotBeConst is true the Parameter is marked as not-const.
53   /// The CanNotBeConst is updated as sub expressions are visited.
54   void markCanNotBeConst(const Expr *E, bool CanNotBeConst);
55 
56   /// Diagnose non const parameters.
57   void diagnoseNonConstParameters();
58 };
59 
60 } // namespace clang::tidy::readability
61 
62 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_NON_CONST_PARAMETER_H
63