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 #include "clang/Lex/Preprocessor.h"
17 
18 namespace clang {
19 
20 namespace ento {
21 
22 // Recursively find any substatements containing macros
23 bool containsMacro(const Stmt *S) {
24   if (S->getBeginLoc().isMacroID())
25     return true;
26 
27   if (S->getEndLoc().isMacroID())
28     return true;
29 
30   for (const Stmt *Child : S->children())
31     if (Child && containsMacro(Child))
32       return true;
33 
34   return false;
35 }
36 
37 // Recursively find any substatements containing enum constants
38 bool containsEnum(const Stmt *S) {
39   const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(S);
40 
41   if (DR && isa<EnumConstantDecl>(DR->getDecl()))
42     return true;
43 
44   for (const Stmt *Child : S->children())
45     if (Child && containsEnum(Child))
46       return true;
47 
48   return false;
49 }
50 
51 // Recursively find any substatements containing static vars
52 bool containsStaticLocal(const Stmt *S) {
53   const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(S);
54 
55   if (DR)
56     if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()))
57       if (VD->isStaticLocal())
58         return true;
59 
60   for (const Stmt *Child : S->children())
61     if (Child && containsStaticLocal(Child))
62       return true;
63 
64   return false;
65 }
66 
67 // Recursively find any substatements containing __builtin_offsetof
68 bool containsBuiltinOffsetOf(const Stmt *S) {
69   if (isa<OffsetOfExpr>(S))
70     return true;
71 
72   for (const Stmt *Child : S->children())
73     if (Child && containsBuiltinOffsetOf(Child))
74       return true;
75 
76   return false;
77 }
78 
79 // Extract lhs and rhs from assignment statement
80 std::pair<const clang::VarDecl *, const clang::Expr *>
81 parseAssignment(const Stmt *S) {
82   const VarDecl *VD = nullptr;
83   const Expr *RHS = nullptr;
84 
85   if (auto Assign = dyn_cast_or_null<BinaryOperator>(S)) {
86     if (Assign->isAssignmentOp()) {
87       // Ordinary assignment
88       RHS = Assign->getRHS();
89       if (auto DE = dyn_cast_or_null<DeclRefExpr>(Assign->getLHS()))
90         VD = dyn_cast_or_null<VarDecl>(DE->getDecl());
91     }
92   } else if (auto PD = dyn_cast_or_null<DeclStmt>(S)) {
93     // Initialization
94     assert(PD->isSingleDecl() && "We process decls one by one");
95     VD = cast<VarDecl>(PD->getSingleDecl());
96     RHS = VD->getAnyInitializer();
97   }
98 
99   return std::make_pair(VD, RHS);
100 }
101 
102 Nullability getNullabilityAnnotation(QualType Type) {
103   const auto *AttrType = Type->getAs<AttributedType>();
104   if (!AttrType)
105     return Nullability::Unspecified;
106   if (AttrType->getAttrKind() == attr::TypeNullable)
107     return Nullability::Nullable;
108   else if (AttrType->getAttrKind() == attr::TypeNonNull)
109     return Nullability::Nonnull;
110   return Nullability::Unspecified;
111 }
112 
113 llvm::Optional<int> tryExpandAsInteger(StringRef Macro,
114                                        const Preprocessor &PP) {
115   const auto *MacroII = PP.getIdentifierInfo(Macro);
116   if (!MacroII)
117     return llvm::None;
118   const MacroInfo *MI = PP.getMacroInfo(MacroII);
119   if (!MI)
120     return llvm::None;
121 
122   // Filter out parens.
123   std::vector<Token> FilteredTokens;
124   FilteredTokens.reserve(MI->tokens().size());
125   for (auto &T : MI->tokens())
126     if (!T.isOneOf(tok::l_paren, tok::r_paren))
127       FilteredTokens.push_back(T);
128 
129   // Parse an integer at the end of the macro definition.
130   const Token &T = FilteredTokens.back();
131   // FIXME: EOF macro token coming from a PCH file on macOS while marked as
132   //        literal, doesn't contain any literal data
133   if (!T.isLiteral() || !T.getLiteralData())
134     return llvm::None;
135   StringRef ValueStr = StringRef(T.getLiteralData(), T.getLength());
136   llvm::APInt IntValue;
137   constexpr unsigned AutoSenseRadix = 0;
138   if (ValueStr.getAsInteger(AutoSenseRadix, IntValue))
139     return llvm::None;
140 
141   // Parse an optional minus sign.
142   size_t Size = FilteredTokens.size();
143   if (Size >= 2) {
144     if (FilteredTokens[Size - 2].is(tok::minus))
145       IntValue = -IntValue;
146   }
147 
148   return IntValue.getSExtValue();
149 }
150 
151 OperatorKind operationKindFromOverloadedOperator(OverloadedOperatorKind OOK,
152                                                  bool IsBinary) {
153   llvm::StringMap<BinaryOperatorKind> BinOps{
154 #define BINARY_OPERATION(Name, Spelling) {Spelling, BO_##Name},
155 #include "clang/AST/OperationKinds.def"
156   };
157   llvm::StringMap<UnaryOperatorKind> UnOps{
158 #define UNARY_OPERATION(Name, Spelling) {Spelling, UO_##Name},
159 #include "clang/AST/OperationKinds.def"
160   };
161 
162   switch (OOK) {
163 #define OVERLOADED_OPERATOR(Name, Spelling, Token, Unary, Binary, MemberOnly)  \
164   case OO_##Name:                                                              \
165     if (IsBinary) {                                                            \
166       auto BinOpIt = BinOps.find(Spelling);                                    \
167       if (BinOpIt != BinOps.end())                                             \
168         return OperatorKind(BinOpIt->second);                                  \
169       else                                                                     \
170         llvm_unreachable("operator was expected to be binary but is not");     \
171     } else {                                                                   \
172       auto UnOpIt = UnOps.find(Spelling);                                      \
173       if (UnOpIt != UnOps.end())                                               \
174         return OperatorKind(UnOpIt->second);                                   \
175       else                                                                     \
176         llvm_unreachable("operator was expected to be unary but is not");      \
177     }                                                                          \
178     break;
179 #include "clang/Basic/OperatorKinds.def"
180   default:
181     llvm_unreachable("unexpected operator kind");
182   }
183 }
184 
185 } // namespace ento
186 } // namespace clang
187