1 //===---------- ExprMutationAnalyzer.h ------------------------------------===//
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 #ifndef LLVM_CLANG_ANALYSIS_ANALYSES_EXPRMUTATIONANALYZER_H
9 #define LLVM_CLANG_ANALYSIS_ANALYSES_EXPRMUTATIONANALYZER_H
10 
11 #include <type_traits>
12 
13 #include "clang/AST/AST.h"
14 #include "clang/ASTMatchers/ASTMatchers.h"
15 #include "llvm/ADT/DenseMap.h"
16 
17 namespace clang {
18 
19 class FunctionParmMutationAnalyzer;
20 
21 /// Analyzes whether any mutative operations are applied to an expression within
22 /// a given statement.
23 class ExprMutationAnalyzer {
24 public:
25   ExprMutationAnalyzer(const Stmt &Stm, ASTContext &Context)
26       : Stm(Stm), Context(Context) {}
27 
28   bool isMutated(const Expr *Exp) { return findMutation(Exp) != nullptr; }
29   bool isMutated(const Decl *Dec) { return findMutation(Dec) != nullptr; }
30   const Stmt *findMutation(const Expr *Exp);
31   const Stmt *findMutation(const Decl *Dec);
32 
33   bool isPointeeMutated(const Expr *Exp) {
34     return findPointeeMutation(Exp) != nullptr;
35   }
36   bool isPointeeMutated(const Decl *Dec) {
37     return findPointeeMutation(Dec) != nullptr;
38   }
39   const Stmt *findPointeeMutation(const Expr *Exp);
40   const Stmt *findPointeeMutation(const Decl *Dec);
41   static bool isUnevaluated(const Stmt *Smt, const Stmt &Stm,
42                             ASTContext &Context);
43 
44 private:
45   using MutationFinder = const Stmt *(ExprMutationAnalyzer::*)(const Expr *);
46   using ResultMap = llvm::DenseMap<const Expr *, const Stmt *>;
47 
48   const Stmt *findMutationMemoized(const Expr *Exp,
49                                    llvm::ArrayRef<MutationFinder> Finders,
50                                    ResultMap &MemoizedResults);
51   const Stmt *tryEachDeclRef(const Decl *Dec, MutationFinder Finder);
52 
53   bool isUnevaluated(const Expr *Exp);
54 
55   const Stmt *findExprMutation(ArrayRef<ast_matchers::BoundNodes> Matches);
56   const Stmt *findDeclMutation(ArrayRef<ast_matchers::BoundNodes> Matches);
57   const Stmt *
58   findExprPointeeMutation(ArrayRef<ast_matchers::BoundNodes> Matches);
59   const Stmt *
60   findDeclPointeeMutation(ArrayRef<ast_matchers::BoundNodes> Matches);
61 
62   const Stmt *findDirectMutation(const Expr *Exp);
63   const Stmt *findMemberMutation(const Expr *Exp);
64   const Stmt *findArrayElementMutation(const Expr *Exp);
65   const Stmt *findCastMutation(const Expr *Exp);
66   const Stmt *findRangeLoopMutation(const Expr *Exp);
67   const Stmt *findReferenceMutation(const Expr *Exp);
68   const Stmt *findFunctionArgMutation(const Expr *Exp);
69 
70   const Stmt &Stm;
71   ASTContext &Context;
72   llvm::DenseMap<const FunctionDecl *,
73                  std::unique_ptr<FunctionParmMutationAnalyzer>>
74       FuncParmAnalyzer;
75   ResultMap Results;
76   ResultMap PointeeResults;
77 };
78 
79 // A convenient wrapper around ExprMutationAnalyzer for analyzing function
80 // params.
81 class FunctionParmMutationAnalyzer {
82 public:
83   FunctionParmMutationAnalyzer(const FunctionDecl &Func, ASTContext &Context);
84 
85   bool isMutated(const ParmVarDecl *Parm) {
86     return findMutation(Parm) != nullptr;
87   }
88   const Stmt *findMutation(const ParmVarDecl *Parm);
89 
90 private:
91   ExprMutationAnalyzer BodyAnalyzer;
92   llvm::DenseMap<const ParmVarDecl *, const Stmt *> Results;
93 };
94 
95 } // namespace clang
96 
97 #endif // LLVM_CLANG_ANALYSIS_ANALYSES_EXPRMUTATIONANALYZER_H
98