clang 20.0.0git
SVals.cpp
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1//===-- SVals.cpp - Abstract RValues for Path-Sens. Value Tracking --------===//
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 SVal, Loc, and NonLoc, classes that represent
10// abstract r-values for use with path-sensitive value tracking.
11//
12//===----------------------------------------------------------------------===//
13
16#include "clang/AST/Decl.h"
17#include "clang/AST/DeclCXX.h"
18#include "clang/AST/Expr.h"
19#include "clang/AST/Type.h"
21#include "clang/Basic/LLVM.h"
28#include "llvm/Support/Casting.h"
29#include "llvm/Support/Compiler.h"
30#include "llvm/Support/ErrorHandling.h"
31#include "llvm/Support/raw_ostream.h"
32#include <cassert>
33#include <optional>
34
35using namespace clang;
36using namespace ento;
37
38//===----------------------------------------------------------------------===//
39// Symbol iteration within an SVal.
40//===----------------------------------------------------------------------===//
41
42//===----------------------------------------------------------------------===//
43// Utility methods.
44//===----------------------------------------------------------------------===//
45
47 if (std::optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) {
48 const MemRegion* R = X->getRegion();
49 if (const FunctionCodeRegion *CTR = R->getAs<FunctionCodeRegion>())
50 if (const auto *FD = dyn_cast<FunctionDecl>(CTR->getDecl()))
51 return FD;
52 }
53
54 if (auto X = getAs<nonloc::PointerToMember>()) {
55 if (const auto *MD = dyn_cast_or_null<CXXMethodDecl>(X->getDecl()))
56 return MD;
57 }
58 return nullptr;
59}
60
61/// If this SVal is a location (subclasses Loc) and wraps a symbol,
62/// return that SymbolRef. Otherwise return 0.
63///
64/// Implicit casts (ex: void* -> char*) can turn Symbolic region into Element
65/// region. If that is the case, gets the underlining region.
66/// When IncludeBaseRegions is set to true and the SubRegion is non-symbolic,
67/// the first symbolic parent region is returned.
68SymbolRef SVal::getAsLocSymbol(bool IncludeBaseRegions) const {
69 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?
70 if (const MemRegion *R = getAsRegion())
71 if (const SymbolicRegion *SymR =
72 IncludeBaseRegions ? R->getSymbolicBase()
73 : dyn_cast<SymbolicRegion>(R->StripCasts()))
74 return SymR->getSymbol();
75
76 return nullptr;
77}
78
79/// Get the symbol in the SVal or its base region.
81 std::optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>();
82
83 if (!X)
84 return nullptr;
85
86 const MemRegion *R = X->getRegion();
87
88 while (const auto *SR = dyn_cast<SubRegion>(R)) {
89 if (const auto *SymR = dyn_cast<SymbolicRegion>(SR))
90 return SymR->getSymbol();
91 else
92 R = SR->getSuperRegion();
93 }
94
95 return nullptr;
96}
97
98/// If this SVal wraps a symbol return that SymbolRef.
99/// Otherwise, return 0.
100///
101/// Casts are ignored during lookup.
102/// \param IncludeBaseRegions The boolean that controls whether the search
103/// should continue to the base regions if the region is not symbolic.
104SymbolRef SVal::getAsSymbol(bool IncludeBaseRegions) const {
105 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?
106 if (std::optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>())
107 return X->getSymbol();
108
109 return getAsLocSymbol(IncludeBaseRegions);
110}
111
112const llvm::APSInt *SVal::getAsInteger() const {
113 if (auto CI = getAs<nonloc::ConcreteInt>())
114 return CI->getValue().get();
115 if (auto CI = getAs<loc::ConcreteInt>())
116 return CI->getValue().get();
117 return nullptr;
118}
119
121 if (std::optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>())
122 return X->getRegion();
123
124 if (std::optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>())
125 return X->getLoc().getAsRegion();
126
127 return nullptr;
128}
129
130namespace {
131class TypeRetrievingVisitor
132 : public FullSValVisitor<TypeRetrievingVisitor, QualType> {
133private:
134 const ASTContext &Context;
135
136public:
137 TypeRetrievingVisitor(const ASTContext &Context) : Context(Context) {}
138
139 QualType VisitMemRegionVal(loc::MemRegionVal MRV) {
140 return Visit(MRV.getRegion());
141 }
142 QualType VisitGotoLabel(loc::GotoLabel GL) {
143 return QualType{Context.VoidPtrTy};
144 }
145 template <class ConcreteInt> QualType VisitConcreteInt(ConcreteInt CI) {
146 const llvm::APSInt &Value = CI.getValue();
147 if (1 == Value.getBitWidth())
148 return Context.BoolTy;
149 return Context.getIntTypeForBitwidth(Value.getBitWidth(), Value.isSigned());
150 }
151 QualType VisitLocAsInteger(nonloc::LocAsInteger LI) {
152 QualType NestedType = Visit(LI.getLoc());
153 if (NestedType.isNull())
154 return NestedType;
155
156 return Context.getIntTypeForBitwidth(LI.getNumBits(),
157 NestedType->isSignedIntegerType());
158 }
159 QualType VisitCompoundVal(nonloc::CompoundVal CV) {
160 return CV.getValue()->getType();
161 }
162 QualType VisitLazyCompoundVal(nonloc::LazyCompoundVal LCV) {
163 return LCV.getRegion()->getValueType();
164 }
165 QualType VisitSymbolVal(nonloc::SymbolVal SV) {
166 return Visit(SV.getSymbol());
167 }
168 QualType VisitSymbolicRegion(const SymbolicRegion *SR) {
169 return Visit(SR->getSymbol());
170 }
171 QualType VisitAllocaRegion(const AllocaRegion *) {
172 return QualType{Context.VoidPtrTy};
173 }
174 QualType VisitTypedRegion(const TypedRegion *TR) {
175 return TR->getLocationType();
176 }
177 QualType VisitSymExpr(const SymExpr *SE) { return SE->getType(); }
178};
179} // end anonymous namespace
180
181QualType SVal::getType(const ASTContext &Context) const {
182 TypeRetrievingVisitor TRV{Context};
183 return TRV.Visit(*this);
184}
185
186const MemRegion *loc::MemRegionVal::stripCasts(bool StripBaseCasts) const {
187 return getRegion()->StripCasts(StripBaseCasts);
188}
189
191 return static_cast<const LazyCompoundValData*>(Data)->getStore();
192}
193
195 return static_cast<const LazyCompoundValData*>(Data)->getRegion();
196}
197
199 return getPTMData().isNull();
200}
201
203 const auto PTMD = this->getPTMData();
204 if (PTMD.isNull())
205 return nullptr;
206
207 const NamedDecl *ND = nullptr;
208 if (const auto *NDP = dyn_cast<const NamedDecl *>(PTMD))
209 ND = NDP;
210 else
211 ND = cast<const PointerToMemberData *>(PTMD)->getDeclaratorDecl();
212
213 return ND;