Bug Summary

File:build/source/llvm/lib/IR/Operator.cpp
Warning:line 78, column 37
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name Operator.cpp -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/source/build-llvm/tools/clang/stage2-bins -resource-dir /usr/lib/llvm-17/lib/clang/17 -D _DEBUG -D _GLIBCXX_ASSERTIONS -D _GNU_SOURCE -D _LIBCPP_ENABLE_ASSERTIONS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I lib/IR -I /build/source/llvm/lib/IR -I include -I /build/source/llvm/include -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-17/lib/clang/17/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/source/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fmacro-prefix-map=/build/source/= -fcoverage-prefix-map=/build/source/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fcoverage-prefix-map=/build/source/= -source-date-epoch 1683717183 -O2 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -Wno-misleading-indentation -std=c++17 -fdeprecated-macro -fdebug-compilation-dir=/build/source/build-llvm/tools/clang/stage2-bins -fdebug-prefix-map=/build/source/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fdebug-prefix-map=/build/source/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2023-05-10-133810-16478-1 -x c++ /build/source/llvm/lib/IR/Operator.cpp
1//===-- Operator.cpp - Implement the LLVM operators -----------------------===//
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 implements the non-inline methods for the LLVM Operator classes.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/IR/Operator.h"
14#include "llvm/IR/DataLayout.h"
15#include "llvm/IR/GetElementPtrTypeIterator.h"
16#include "llvm/IR/Instructions.h"
17
18#include "ConstantsContext.h"
19
20namespace llvm {
21bool Operator::hasPoisonGeneratingFlags() const {
22 switch (getOpcode()) {
23 case Instruction::Add:
24 case Instruction::Sub:
25 case Instruction::Mul:
26 case Instruction::Shl: {
27 auto *OBO = cast<OverflowingBinaryOperator>(this);
28 return OBO->hasNoUnsignedWrap() || OBO->hasNoSignedWrap();
29 }
30 case Instruction::UDiv:
31 case Instruction::SDiv:
32 case Instruction::AShr:
33 case Instruction::LShr:
34 return cast<PossiblyExactOperator>(this)->isExact();
35 case Instruction::GetElementPtr: {
36 auto *GEP = cast<GEPOperator>(this);
37 // Note: inrange exists on constexpr only
38 return GEP->isInBounds() || GEP->getInRangeIndex() != std::nullopt;
39 }
40 default:
41 if (const auto *FP = dyn_cast<FPMathOperator>(this))
42 return FP->hasNoNaNs() || FP->hasNoInfs();
43 return false;
44 }
45}
46
47bool Operator::hasPoisonGeneratingFlagsOrMetadata() const {
48 if (hasPoisonGeneratingFlags())
49 return true;
50 auto *I = dyn_cast<Instruction>(this);
51 return I && I->hasPoisonGeneratingMetadata();
52}
53
54Type *GEPOperator::getSourceElementType() const {
55 if (auto *I = dyn_cast<GetElementPtrInst>(this))
56 return I->getSourceElementType();
57 return cast<GetElementPtrConstantExpr>(this)->getSourceElementType();
58}
59
60Type *GEPOperator::getResultElementType() const {
61 if (auto *I = dyn_cast<GetElementPtrInst>(this))
62 return I->getResultElementType();
63 return cast<GetElementPtrConstantExpr>(this)->getResultElementType();
64}
65
66Align GEPOperator::getMaxPreservedAlignment(const DataLayout &DL) const {
67 /// compute the worse possible offset for every level of the GEP et accumulate
68 /// the minimum alignment into Result.
69
70 Align Result = Align(llvm::Value::MaximumAlignment);
71 for (gep_type_iterator GTI = gep_type_begin(this), GTE = gep_type_end(this);
1
Loop condition is true. Entering loop body
→
72 GTI != GTE; ++GTI) {
73 uint64_t Offset;
74 ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand());
2
←
Assuming the object is not a 'CastReturnType'
→
3
←
'OpC' initialized to a null pointer value
→
75
76 if (StructType *STy = GTI.getStructTypeOrNull()) {
4
←
Assuming 'STy' is non-null
→
5
←
Taking true branch
→
77 const StructLayout *SL = DL.getStructLayout(STy);
78 Offset = SL->getElementOffset(OpC->getZExtValue());
6
←
Called C++ object pointer is null
79 } else {
80 assert(GTI.isSequential() && "should be sequencial")(static_cast <bool> (GTI.isSequential() && "should be sequencial"
) ? void (0) : __assert_fail ("GTI.isSequential() && \"should be sequencial\""
, "llvm/lib/IR/Operator.cpp", 80, __extension__ __PRETTY_FUNCTION__
));
81 /// If the index isn't known, we take 1 because it is the index that will
82 /// give the worse alignment of the offset.
83 const uint64_t ElemCount = OpC ? OpC->getZExtValue() : 1;
84 Offset = DL.getTypeAllocSize(GTI.getIndexedType()) * ElemCount;
85 }
86 Result = Align(MinAlign(Offset, Result.value()));
87 }
88 return Result;
89}
90
91bool GEPOperator::accumulateConstantOffset(
92 const DataLayout &DL, APInt &Offset,
93 function_ref<bool(Value &, APInt &)> ExternalAnalysis) const {
94 assert(Offset.getBitWidth() ==(static_cast <bool> (Offset.getBitWidth() == DL.getIndexSizeInBits
(getPointerAddressSpace()) && "The offset bit width does not match DL specification."
) ? void (0) : __assert_fail ("Offset.getBitWidth() == DL.getIndexSizeInBits(getPointerAddressSpace()) && \"The offset bit width does not match DL specification.\""
, "llvm/lib/IR/Operator.cpp", 96, __extension__ __PRETTY_FUNCTION__
))
95 DL.getIndexSizeInBits(getPointerAddressSpace()) &&(static_cast <bool> (Offset.getBitWidth() == DL.getIndexSizeInBits
(getPointerAddressSpace()) && "The offset bit width does not match DL specification."
) ? void (0) : __assert_fail ("Offset.getBitWidth() == DL.getIndexSizeInBits(getPointerAddressSpace()) && \"The offset bit width does not match DL specification.\""
, "llvm/lib/IR/Operator.cpp", 96, __extension__ __PRETTY_FUNCTION__
))
96 "The offset bit width does not match DL specification.")(static_cast <bool> (Offset.getBitWidth() == DL.getIndexSizeInBits
(getPointerAddressSpace()) && "The offset bit width does not match DL specification."
) ? void (0) : __assert_fail ("Offset.getBitWidth() == DL.getIndexSizeInBits(getPointerAddressSpace()) && \"The offset bit width does not match DL specification.\""
, "llvm/lib/IR/Operator.cpp", 96, __extension__ __PRETTY_FUNCTION__
));
97 SmallVector<const Value *> Index(llvm::drop_begin(operand_values()));
98 return GEPOperator::accumulateConstantOffset(getSourceElementType(), Index,
99 DL, Offset, ExternalAnalysis);
100}
101
102bool GEPOperator::accumulateConstantOffset(
103 Type *SourceType, ArrayRef<const Value *> Index, const DataLayout &DL,
104 APInt &Offset, function_ref<bool(Value &, APInt &)> ExternalAnalysis) {
105 bool UsedExternalAnalysis = false;
106 auto AccumulateOffset = [&](APInt Index, uint64_t Size) -> bool {
107 Index = Index.sextOrTrunc(Offset.getBitWidth());
108 APInt IndexedSize = APInt(Offset.getBitWidth(), Size);
109 // For array or vector indices, scale the index by the size of the type.
110 if (!UsedExternalAnalysis) {
111 Offset += Index * IndexedSize;
112 } else {
113 // External Analysis can return a result higher/lower than the value
114 // represents. We need to detect overflow/underflow.
115 bool Overflow = false;
116 APInt OffsetPlus = Index.smul_ov(IndexedSize, Overflow);
117 if (Overflow)
118 return false;
119 Offset = Offset.sadd_ov(OffsetPlus, Overflow);
120 if (Overflow)
121 return false;
122 }
123 return true;
124 };
125 auto begin = generic_gep_type_iterator<decltype(Index.begin())>::begin(
126 SourceType, Index.begin());
127 auto end = generic_gep_type_iterator<decltype(Index.end())>::end(Index.end());
128 for (auto GTI = begin, GTE = end; GTI != GTE; ++GTI) {
129 // Scalable vectors are multiplied by a runtime constant.
130 bool ScalableType = false;
131 if (isa<ScalableVectorType>(GTI.getIndexedType()))
132 ScalableType = true;
133
134 Value *V = GTI.getOperand();
135 StructType *STy = GTI.getStructTypeOrNull();
136 // Handle ConstantInt if possible.
137 if (auto ConstOffset = dyn_cast<ConstantInt>(V)) {
138 if (ConstOffset->isZero())
139 continue;
140 // if the type is scalable and the constant is not zero (vscale * n * 0 =
141 // 0) bailout.
142 if (ScalableType)
143 return false;
144 // Handle a struct index, which adds its field offset to the pointer.
145 if (STy) {
146 unsigned ElementIdx = ConstOffset->getZExtValue();
147 const StructLayout *SL = DL.getStructLayout(STy);
148 // Element offset is in bytes.
149 if (!AccumulateOffset(
150 APInt(Offset.getBitWidth(), SL->getElementOffset(ElementIdx)),
151 1))
152 return false;
153 continue;
154 }
155 if (!AccumulateOffset(ConstOffset->getValue(),
156 DL.getTypeAllocSize(GTI.getIndexedType())))
157 return false;
158 continue;
159 }
160
161 // The operand is not constant, check if an external analysis was provided.
162 // External analsis is not applicable to a struct type.
163 if (!ExternalAnalysis || STy || ScalableType)
164 return false;
165 APInt AnalysisIndex;
166 if (!ExternalAnalysis(*V, AnalysisIndex))
167 return false;
168 UsedExternalAnalysis = true;
169 if (!AccumulateOffset(AnalysisIndex,
170 DL.getTypeAllocSize(GTI.getIndexedType())))
171 return false;
172 }
173 return true;
174}
175
176bool GEPOperator::collectOffset(
177 const DataLayout &DL, unsigned BitWidth,
178 MapVector<Value *, APInt> &VariableOffsets,
179 APInt &ConstantOffset) const {
180 assert(BitWidth == DL.getIndexSizeInBits(getPointerAddressSpace()) &&(static_cast <bool> (BitWidth == DL.getIndexSizeInBits(
getPointerAddressSpace()) && "The offset bit width does not match DL specification."
) ? void (0) : __assert_fail ("BitWidth == DL.getIndexSizeInBits(getPointerAddressSpace()) && \"The offset bit width does not match DL specification.\""
, "llvm/lib/IR/Operator.cpp", 181, __extension__ __PRETTY_FUNCTION__
))
181 "The offset bit width does not match DL specification.")(static_cast <bool> (BitWidth == DL.getIndexSizeInBits(
getPointerAddressSpace()) && "The offset bit width does not match DL specification."
) ? void (0) : __assert_fail ("BitWidth == DL.getIndexSizeInBits(getPointerAddressSpace()) && \"The offset bit width does not match DL specification.\""
, "llvm/lib/IR/Operator.cpp", 181, __extension__ __PRETTY_FUNCTION__
));
182
183 auto CollectConstantOffset = [&](APInt Index, uint64_t Size) {
184 Index = Index.sextOrTrunc(BitWidth);
185 APInt IndexedSize = APInt(BitWidth, Size);
186 ConstantOffset += Index * IndexedSize;
187 };
188
189 for (gep_type_iterator GTI = gep_type_begin(this), GTE = gep_type_end(this);
190 GTI != GTE; ++GTI) {
191 // Scalable vectors are multiplied by a runtime constant.
192 bool ScalableType = isa<ScalableVectorType>(GTI.getIndexedType());
193
194 Value *V = GTI.getOperand();
195 StructType *STy = GTI.getStructTypeOrNull();
196 // Handle ConstantInt if possible.
197 if (auto ConstOffset = dyn_cast<ConstantInt>(V)) {
198 if (ConstOffset->isZero())
199 continue;
200 // If the type is scalable and the constant is not zero (vscale * n * 0 =
201 // 0) bailout.
202 // TODO: If the runtime value is accessible at any point before DWARF
203 // emission, then we could potentially keep a forward reference to it
204 // in the debug value to be filled in later.
205 if (ScalableType)
206 return false;
207 // Handle a struct index, which adds its field offset to the pointer.
208 if (STy) {
209 unsigned ElementIdx = ConstOffset->getZExtValue();
210 const StructLayout *SL = DL.getStructLayout(STy);
211 // Element offset is in bytes.
212 CollectConstantOffset(APInt(BitWidth, SL->getElementOffset(ElementIdx)),
213 1);
214 continue;
215 }
216 CollectConstantOffset(ConstOffset->getValue(),
217 DL.getTypeAllocSize(GTI.getIndexedType()));
218 continue;
219 }
220
221 if (STy || ScalableType)
222 return false;
223 APInt IndexedSize =
224 APInt(BitWidth, DL.getTypeAllocSize(GTI.getIndexedType()));
225 // Insert an initial offset of 0 for V iff none exists already, then
226 // increment the offset by IndexedSize.
227 if (!IndexedSize.isZero()) {
228 VariableOffsets.insert({V, APInt(BitWidth, 0)});
229 VariableOffsets[V] += IndexedSize;
230 }
231 }
232 return true;
233}
234
235void FastMathFlags::print(raw_ostream &O) const {
236 if (all())
237 O << " fast";
238 else {
239 if (allowReassoc())
240 O << " reassoc";
241 if (noNaNs())
242 O << " nnan";
243 if (noInfs())
244 O << " ninf";
245 if (noSignedZeros())
246 O << " nsz";
247 if (allowReciprocal())
248 O << " arcp";
249 if (allowContract())
250 O << " contract";
251 if (approxFunc())
252 O << " afn";
253 }
254}
255} // namespace llvm