clang-tools-extra/clang-tidy/altera/IdDependentBackwardBranchCheck.h

   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 {
  27     IdDependencyRecord(const VarDecl *Declaration, SourceLocation Location,
  28                        const llvm::Twine &Message)
  29         : VariableDeclaration(Declaration), Location(Location),
  30           Message(Message.str()) {}
  31     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:
  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