1 //===---- CheckerHelpers.cpp - Helper functions for checkers ----*- 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 //  This file defines several static functions for use in checkers.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerHelpers.h"
14 #include "clang/AST/Decl.h"
15 #include "clang/AST/Expr.h"
16 
17 namespace clang {
18 
19 namespace ento {
20 
21 // Recursively find any substatements containing macros
22 bool containsMacro(const Stmt *S) {
23   if (S->getBeginLoc().isMacroID())
24     return true;
25 
26   if (S->getEndLoc().isMacroID())
27     return true;
28 
29   for (const Stmt *Child : S->children())
30     if (Child && containsMacro(Child))
31       return true;
32 
33   return false;
34 }
35 
36 // Recursively find any substatements containing enum constants
37 bool containsEnum(const Stmt *S) {
38   const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(S);
39 
40   if (DR && isa<EnumConstantDecl>(DR->getDecl()))
41     return true;
42 
43   for (const Stmt *Child : S->children())
44     if (Child && containsEnum(Child))
45       return true;
46 
47   return false;
48 }
49 
50 // Recursively find any substatements containing static vars
51 bool containsStaticLocal(const Stmt *S) {
52   const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(S);
53 
54   if (DR)
55     if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()))
56       if (VD->isStaticLocal())
57         return true;
58 
59   for (const Stmt *Child : S->children())
60     if (Child && containsStaticLocal(Child))
61       return true;
62 
63   return false;
64 }
65 
66 // Recursively find any substatements containing __builtin_offsetof
67 bool containsBuiltinOffsetOf(const Stmt *S) {
68   if (isa<OffsetOfExpr>(S))
69     return true;
70 
71   for (const Stmt *Child : S->children())
72     if (Child && containsBuiltinOffsetOf(Child))
73       return true;
74 
75   return false;
76 }
77 
78 // Extract lhs and rhs from assignment statement
79 std::pair<const clang::VarDecl *, const clang::Expr *>
80 parseAssignment(const Stmt *S) {
81   const VarDecl *VD = nullptr;
82   const Expr *RHS = nullptr;
83 
84   if (auto Assign = dyn_cast_or_null<BinaryOperator>(S)) {
85     if (Assign->isAssignmentOp()) {
86       // Ordinary assignment
87       RHS = Assign->getRHS();
88       if (auto DE = dyn_cast_or_null<DeclRefExpr>(Assign->getLHS()))
89         VD = dyn_cast_or_null<VarDecl>(DE->getDecl());
90     }
91   } else if (auto PD = dyn_cast_or_null<DeclStmt>(S)) {
92     // Initialization
93     assert(PD->isSingleDecl() && "We process decls one by one");
94     VD = cast<VarDecl>(PD->getSingleDecl());
95     RHS = VD->getAnyInitializer();
96   }
97 
98   return std::make_pair(VD, RHS);
99 }
100 
101 Nullability getNullabilityAnnotation(QualType Type) {
102   const auto *AttrType = Type->getAs<AttributedType>();
103   if (!AttrType)
104     return Nullability::Unspecified;
105   if (AttrType->getAttrKind() == attr::TypeNullable)
106     return Nullability::Nullable;
107   else if (AttrType->getAttrKind() == attr::TypeNonNull)
108     return Nullability::Nonnull;
109   return Nullability::Unspecified;
110 }
111 
112 
113 } // end namespace ento
114 } // end namespace clang
115