1 //===- DynamicExtent.cpp - Dynamic extent related APIs ----------*- 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 APIs that track and query dynamic extent information.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "clang/StaticAnalyzer/Core/PathSensitive/DynamicExtent.h"
14 #include "clang/AST/Expr.h"
15 #include "clang/Basic/LLVM.h"
16 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
17 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
20 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
21
22 REGISTER_MAP_WITH_PROGRAMSTATE(DynamicExtentMap, const clang::ento::MemRegion *,
23 clang::ento::DefinedOrUnknownSVal)
24
25 namespace clang {
26 namespace ento {
27
getDynamicExtent(ProgramStateRef State,const MemRegion * MR,SValBuilder & SVB)28 DefinedOrUnknownSVal getDynamicExtent(ProgramStateRef State,
29 const MemRegion *MR, SValBuilder &SVB) {
30 MR = MR->StripCasts();
31
32 if (const DefinedOrUnknownSVal *Size = State->get<DynamicExtentMap>(MR))
33 return *Size;
34
35 return MR->getMemRegionManager().getStaticSize(MR, SVB);
36 }
37
getElementExtent(QualType Ty,SValBuilder & SVB)38 DefinedOrUnknownSVal getElementExtent(QualType Ty, SValBuilder &SVB) {
39 return SVB.makeIntVal(SVB.getContext().getTypeSizeInChars(Ty).getQuantity(),
40 SVB.getArrayIndexType());
41 }
42
getDynamicElementCount(ProgramStateRef State,const MemRegion * MR,SValBuilder & SVB,QualType ElementTy)43 DefinedOrUnknownSVal getDynamicElementCount(ProgramStateRef State,
44 const MemRegion *MR,
45 SValBuilder &SVB,
46 QualType ElementTy) {
47 assert(MR != nullptr && "Not-null region expected");
48 MR = MR->StripCasts();
49
50 DefinedOrUnknownSVal Size = getDynamicExtent(State, MR, SVB);
51 SVal ElementSize = getElementExtent(ElementTy, SVB);
52
53 SVal ElementCount =
54 SVB.evalBinOp(State, BO_Div, Size, ElementSize, SVB.getArrayIndexType());
55
56 return ElementCount.castAs<DefinedOrUnknownSVal>();
57 }
58
getDynamicExtentWithOffset(ProgramStateRef State,SVal BufV)59 SVal getDynamicExtentWithOffset(ProgramStateRef State, SVal BufV) {
60 SValBuilder &SvalBuilder = State->getStateManager().getSValBuilder();
61 const MemRegion *MRegion = BufV.getAsRegion();
62 if (!MRegion)
63 return UnknownVal();
64 RegionOffset Offset = MRegion->getAsOffset();
65 if (Offset.hasSymbolicOffset())
66 return UnknownVal();
67 const MemRegion *BaseRegion = MRegion->getBaseRegion();
68 if (!BaseRegion)
69 return UnknownVal();
70
71 NonLoc OffsetInBytes = SvalBuilder.makeArrayIndex(
72 Offset.getOffset() /
73 MRegion->getMemRegionManager().getContext().getCharWidth());
74 DefinedOrUnknownSVal ExtentInBytes =
75 getDynamicExtent(State, BaseRegion, SvalBuilder);
76
77 return SvalBuilder.evalBinOp(State, BinaryOperator::Opcode::BO_Sub,
78 ExtentInBytes, OffsetInBytes,
79 SvalBuilder.getArrayIndexType());
80 }
81
setDynamicExtent(ProgramStateRef State,const MemRegion * MR,DefinedOrUnknownSVal Size,SValBuilder & SVB)82 ProgramStateRef setDynamicExtent(ProgramStateRef State, const MemRegion *MR,
83 DefinedOrUnknownSVal Size, SValBuilder &SVB) {
84 MR = MR->StripCasts();
85
86 if (Size.isUnknown())
87 return State;
88
89 return State->set<DynamicExtentMap>(MR->StripCasts(), Size);
90 }
91
92 } // namespace ento
93 } // namespace clang
94