1 //===--- IdDependentBackwardBranchCheck.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_ALTERA_IDDEPENDENTBACKWARDBRANCHCHECK_H
10 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ALTERA_IDDEPENDENTBACKWARDBRANCHCHECK_H
11 
12 #include "../ClangTidyCheck.h"
13 
14 namespace clang::tidy::altera {
15 
16 /// Finds ID-dependent variables and fields used within loops, and warns of
17 /// their usage. Using these variables in loops can lead to performance
18 /// degradation.
19 ///
20 /// For the user-facing documentation see:
21 /// http://clang.llvm.org/extra/clang-tidy/checks/altera/id-dependent-backward-branch.html
22 class IdDependentBackwardBranchCheck : public ClangTidyCheck {
23 private:
24   enum LoopType { UnknownLoop = -1, DoLoop = 0, WhileLoop = 1, ForLoop = 2 };
25   // Stores information necessary for printing out source of error.
26   struct IdDependencyRecord {
IdDependencyRecordIdDependencyRecord27     IdDependencyRecord(const VarDecl *Declaration, SourceLocation Location,
28                        const llvm::Twine &Message)
29         : VariableDeclaration(Declaration), Location(Location),
30           Message(Message.str()) {}
IdDependencyRecordIdDependencyRecord31     IdDependencyRecord(const FieldDecl *Declaration, SourceLocation Location,
32                        const llvm::Twine &Message)
33         : FieldDeclaration(Declaration), Location(Location),
34           Message(Message.str()) {}
35     IdDependencyRecord() = default;
36     const VarDecl *VariableDeclaration = nullptr;
37     const FieldDecl *FieldDeclaration = nullptr;
38     SourceLocation Location;
39     std::string Message;
40   };
41   // Stores the locations where ID-dependent variables are created.
42   std::map<const VarDecl *, IdDependencyRecord> IdDepVarsMap;
43   // Stores the locations where ID-dependent fields are created.
44   std::map<const FieldDecl *, IdDependencyRecord> IdDepFieldsMap;
45   /// Returns an IdDependencyRecord if the Expression contains an ID-dependent
46   /// variable, returns a nullptr otherwise.
47   IdDependencyRecord *hasIdDepVar(const Expr *Expression);
48   /// Returns an IdDependencyRecord if the Expression contains an ID-dependent
49   /// field, returns a nullptr otherwise.
50   IdDependencyRecord *hasIdDepField(const Expr *Expression);
51   /// Stores the location an ID-dependent variable is created from a call to
52   /// an ID function in IdDepVarsMap.
53   void saveIdDepVar(const Stmt *Statement, const VarDecl *Variable);
54   /// Stores the location an ID-dependent field is created from a call to an ID
55   /// function in IdDepFieldsMap.
56   void saveIdDepField(const Stmt *Statement, const FieldDecl *Field);
57   /// Stores the location an ID-dependent variable is created from a reference
58   /// to another ID-dependent variable or field in IdDepVarsMap.
59   void saveIdDepVarFromReference(const DeclRefExpr *RefExpr,
60                                  const MemberExpr *MemExpr,
61                                  const VarDecl *PotentialVar);
62   /// Stores the location an ID-dependent field is created from a reference to
63   /// another ID-dependent variable or field in IdDepFieldsMap.
64   void saveIdDepFieldFromReference(const DeclRefExpr *RefExpr,
65                                    const MemberExpr *MemExpr,
66                                    const FieldDecl *PotentialField);
67   /// Returns the loop type.
68   LoopType getLoopType(const Stmt *Loop);
69 
70 public:
IdDependentBackwardBranchCheck(StringRef Name,ClangTidyContext * Context)71   IdDependentBackwardBranchCheck(StringRef Name, ClangTidyContext *Context)
72       : ClangTidyCheck(Name, Context) {}
73   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
74   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
75 };
76 
77 } // namespace clang::tidy::altera
78 
79 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ALTERA_IDDEPENDENTBACKWARDBRANCHCHECK_H
80