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 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
18 #include <optional>
19
20 namespace clang {
21
22 namespace ento {
23
24 // Recursively find any substatements containing macros
containsMacro(const Stmt * S)25 bool containsMacro(const Stmt *S) {
26 if (S->getBeginLoc().isMacroID())
27 return true;
28
29 if (S->getEndLoc().isMacroID())
30 return true;
31
32 for (const Stmt *Child : S->children())
33 if (Child && containsMacro(Child))
34 return true;
35
36 return false;
37 }
38
39 // Recursively find any substatements containing enum constants
containsEnum(const Stmt * S)40 bool containsEnum(const Stmt *S) {
41 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(S);
42
43 if (DR && isa<EnumConstantDecl>(DR->getDecl()))
44 return true;
45
46 for (const Stmt *Child : S->children())
47 if (Child && containsEnum(Child))
48 return true;
49
50 return false;
51 }
52
53 // Recursively find any substatements containing static vars
containsStaticLocal(const Stmt * S)54 bool containsStaticLocal(const Stmt *S) {
55 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(S);
56
57 if (DR)
58 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()))
59 if (VD->isStaticLocal())
60 return true;
61
62 for (const Stmt *Child : S->children())
63 if (Child && containsStaticLocal(Child))
64 return true;
65
66 return false;
67 }
68
69 // Recursively find any substatements containing __builtin_offsetof
containsBuiltinOffsetOf(const Stmt * S)70 bool containsBuiltinOffsetOf(const Stmt *S) {
71 if (isa<OffsetOfExpr>(S))
72 return true;
73
74 for (const Stmt *Child : S->children())
75 if (Child && containsBuiltinOffsetOf(Child))
76 return true;
77
78 return false;
79 }
80
81 // Extract lhs and rhs from assignment statement
82 std::pair<const clang::VarDecl *, const clang::Expr *>
parseAssignment(const Stmt * S)83 parseAssignment(const Stmt *S) {
84 const VarDecl *VD = nullptr;
85 const Expr *RHS = nullptr;
86
87 if (auto Assign = dyn_cast_or_null<BinaryOperator>(S)) {
88 if (Assign->isAssignmentOp()) {
89 // Ordinary assignment
90 RHS = Assign->getRHS();
91 if (auto DE = dyn_cast_or_null<DeclRefExpr>(Assign->getLHS()))
92 VD = dyn_cast_or_null<VarDecl>(DE->getDecl());
93 }
94 } else if (auto PD = dyn_cast_or_null<DeclStmt>(S)) {
95 // Initialization
96 assert(PD->isSingleDecl() && "We process decls one by one");
97 VD = cast<VarDecl>(PD->getSingleDecl());
98 RHS = VD->getAnyInitializer();
99 }
100
101 return std::make_pair(VD, RHS);
102 }
103
getNullabilityAnnotation(QualType Type)104 Nullability getNullabilityAnnotation(QualType Type) {
105 const auto *AttrType = Type->getAs<AttributedType>();
106 if (!AttrType)
107 return Nullability::Unspecified;
108 if (AttrType->getAttrKind() == attr::TypeNullable)
109 return Nullability::Nullable;
110 else if (AttrType->getAttrKind() == attr::TypeNonNull)
111 return Nullability::Nonnull;
112 return Nullability::Unspecified;
113 }
114
tryExpandAsInteger(StringRef Macro,const Preprocessor & PP)115 std::optional<int> tryExpandAsInteger(StringRef Macro, const Preprocessor &PP) {
116 const auto *MacroII = PP.getIdentifierInfo(Macro);
117 if (!MacroII)
118 return std::nullopt;
119 const MacroInfo *MI = PP.getMacroInfo(MacroII);
120 if (!MI)
121 return std::nullopt;
122
123 // Filter out parens.
124 std::vector<Token> FilteredTokens;
125 FilteredTokens.reserve(MI->tokens().size());
126 for (auto &T : MI->tokens())
127 if (!T.isOneOf(tok::l_paren, tok::r_paren))
128 FilteredTokens.push_back(T);
129
130 // Parse an integer at the end of the macro definition.
131 const Token &T = FilteredTokens.back();
132
133 if (!T.isLiteral())
134 return std::nullopt;
135
136 bool InvalidSpelling = false;
137 SmallVector<char> Buffer(T.getLength());
138 // `Preprocessor::getSpelling` can get the spelling of the token regardless of
139 // whether the macro is defined in a PCH or not:
140 StringRef ValueStr = PP.getSpelling(T, Buffer, &InvalidSpelling);
141
142 if (InvalidSpelling)
143 return std::nullopt;
144
145 llvm::APInt IntValue;
146 constexpr unsigned AutoSenseRadix = 0;
147 if (ValueStr.getAsInteger(AutoSenseRadix, IntValue))
148 return std::nullopt;
149
150 // Parse an optional minus sign.
151 size_t Size = FilteredTokens.size();
152 if (Size >= 2) {
153 if (FilteredTokens[Size - 2].is(tok::minus))
154 IntValue = -IntValue;
155 }
156
157 return IntValue.getSExtValue();
158 }
159
operationKindFromOverloadedOperator(OverloadedOperatorKind OOK,bool IsBinary)160 OperatorKind operationKindFromOverloadedOperator(OverloadedOperatorKind OOK,
161 bool IsBinary) {
162 llvm::StringMap<BinaryOperatorKind> BinOps{
163 #define BINARY_OPERATION(Name, Spelling) {Spelling, BO_##Name},
164 #include "clang/AST/OperationKinds.def"
165 };
166 llvm::StringMap<UnaryOperatorKind> UnOps{
167 #define UNARY_OPERATION(Name, Spelling) {Spelling, UO_##Name},
168 #include "clang/AST/OperationKinds.def"
169 };
170
171 switch (OOK) {
172 #define OVERLOADED_OPERATOR(Name, Spelling, Token, Unary, Binary, MemberOnly) \
173 case OO_##Name: \
174 if (IsBinary) { \
175 auto BinOpIt = BinOps.find(Spelling); \
176 if (BinOpIt != BinOps.end()) \
177 return OperatorKind(BinOpIt->second); \
178 else \
179 llvm_unreachable("operator was expected to be binary but is not"); \
180 } else { \
181 auto UnOpIt = UnOps.find(Spelling); \
182 if (UnOpIt != UnOps.end()) \
183 return OperatorKind(UnOpIt->second); \
184 else \
185 llvm_unreachable("operator was expected to be unary but is not"); \
186 } \
187 break;
188 #include "clang/Basic/OperatorKinds.def"
189 default:
190 llvm_unreachable("unexpected operator kind");
191 }
192 }
193
getPointeeVal(SVal PtrSVal,ProgramStateRef State)194 std::optional<SVal> getPointeeVal(SVal PtrSVal, ProgramStateRef State) {
195 if (const auto *Ptr = PtrSVal.getAsRegion()) {
196 return State->getSVal(Ptr);
197 }
198 return std::nullopt;
199 }
200
isWithinStdNamespace(const Decl * D)201 bool isWithinStdNamespace(const Decl *D) {
202 const DeclContext *DC = D->getDeclContext();
203 while (DC) {
204 if (const auto *NS = dyn_cast<NamespaceDecl>(DC);
205 NS && NS->isStdNamespace())
206 return true;
207 DC = DC->getParent();
208 }
209 return false;
210 }
211
212 } // namespace ento
213 } // namespace clang
214