Bug Summary

File:lib/Support/SmallPtrSet.cpp
Warning:line 110, column 3
Null pointer passed as an argument to a 'nonnull' parameter

Annotated Source Code

1//===- llvm/ADT/SmallPtrSet.cpp - 'Normally small' pointer set ------------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the SmallPtrSet class. See SmallPtrSet.h for an
11// overview of the algorithm.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/ADT/SmallPtrSet.h"
16#include "llvm/ADT/DenseMapInfo.h"
17#include "llvm/Support/MathExtras.h"
18#include "llvm/Support/ErrorHandling.h"
19#include <algorithm>
20#include <cassert>
21#include <cstdlib>
22
23using namespace llvm;
24
25void SmallPtrSetImplBase::shrink_and_clear() {
26 assert(!isSmall() && "Can't shrink a small set!")((!isSmall() && "Can't shrink a small set!") ? static_cast
<void> (0) : __assert_fail ("!isSmall() && \"Can't shrink a small set!\""
, "/build/llvm-toolchain-snapshot-6.0~svn318211/lib/Support/SmallPtrSet.cpp"
, 26, __PRETTY_FUNCTION__))
;
27 free(CurArray);
28
29 // Reduce the number of buckets.
30 unsigned Size = size();
31 CurArraySize = Size > 16 ? 1 << (Log2_32_Ceil(Size) + 1) : 32;
32 NumNonEmpty = NumTombstones = 0;
33
34 // Install the new array. Clear all the buckets to empty.
35 CurArray = (const void**)malloc(sizeof(void*) * CurArraySize);
36 if (CurArray == nullptr)
37 report_bad_alloc_error("Allocation of SmallPtrSet bucket array failed.");
38
39 memset(CurArray, -1, CurArraySize*sizeof(void*));
40}
41
42std::pair<const void *const *, bool>
43SmallPtrSetImplBase::insert_imp_big(const void *Ptr) {
44 if (LLVM_UNLIKELY(size() * 4 >= CurArraySize * 3)__builtin_expect((bool)(size() * 4 >= CurArraySize * 3), false
)
) {
1
Taking false branch
45 // If more than 3/4 of the array is full, grow.
46 Grow(CurArraySize < 64 ? 128 : CurArraySize * 2);
47 } else if (LLVM_UNLIKELY(CurArraySize - NumNonEmpty < CurArraySize / 8)__builtin_expect((bool)(CurArraySize - NumNonEmpty < CurArraySize
/ 8), false)
) {
2
Taking true branch
48 // If fewer of 1/8 of the array is empty (meaning that many are filled with
49 // tombstones), rehash.
50 Grow(CurArraySize);
3
Calling 'SmallPtrSetImplBase::Grow'
51 }
52
53 // Okay, we know we have space. Find a hash bucket.
54 const void **Bucket = const_cast<const void**>(FindBucketFor(Ptr));
55 if (*Bucket == Ptr)
56 return std::make_pair(Bucket, false); // Already inserted, good.
57
58 // Otherwise, insert it!
59 if (*Bucket == getTombstoneMarker())
60 --NumTombstones;
61 else
62 ++NumNonEmpty; // Track density.
63 *Bucket = Ptr;
64 incrementEpoch();
65 return std::make_pair(Bucket, true);
66}
67
68const void * const *SmallPtrSetImplBase::FindBucketFor(const void *Ptr) const {
69 unsigned Bucket = DenseMapInfo<void *>::getHashValue(Ptr) & (CurArraySize-1);
70 unsigned ArraySize = CurArraySize;
71 unsigned ProbeAmt = 1;
72 const void *const *Array = CurArray;
73 const void *const *Tombstone = nullptr;
74 while (true) {
75 // If we found an empty bucket, the pointer doesn't exist in the set.
76 // Return a tombstone if we've seen one so far, or the empty bucket if
77 // not.
78 if (LLVM_LIKELY(Array[Bucket] == getEmptyMarker())__builtin_expect((bool)(Array[Bucket] == getEmptyMarker()), true
)
)
79 return Tombstone ? Tombstone : Array+Bucket;
80
81 // Found Ptr's bucket?
82 if (LLVM_LIKELY(Array[Bucket] == Ptr)__builtin_expect((bool)(Array[Bucket] == Ptr), true))
83 return Array+Bucket;
84
85 // If this is a tombstone, remember it. If Ptr ends up not in the set, we
86 // prefer to return it than something that would require more probing.
87 if (Array[Bucket] == getTombstoneMarker() && !Tombstone)
88 Tombstone = Array+Bucket; // Remember the first tombstone found.
89
90 // It's a hash collision or a tombstone. Reprobe.
91 Bucket = (Bucket + ProbeAmt++) & (ArraySize-1);
92 }
93}
94
95/// Grow - Allocate a larger backing store for the buckets and move it over.
96///
97void SmallPtrSetImplBase::Grow(unsigned NewSize) {
98 const void **OldBuckets = CurArray;
99 const void **OldEnd = EndPointer();
100 bool WasSmall = isSmall();
101
102 // Install the new array. Clear all the buckets to empty.
103 const void **NewBuckets = (const void**) malloc(sizeof(void*) * NewSize);
4
'NewBuckets' initialized here
104 if (NewBuckets == nullptr)
5
Assuming pointer value is null
6
Taking true branch
105 report_bad_alloc_error("Allocation of SmallPtrSet bucket array failed.");
106
107 // Reset member only if memory was allocated successfully
108 CurArray = NewBuckets;
7
Null pointer value stored to field 'CurArray'
109 CurArraySize = NewSize;
110 memset(CurArray, -1, NewSize*sizeof(void*));
8
Null pointer passed as an argument to a 'nonnull' parameter
111
112 // Copy over all valid entries.
113 for (const void **BucketPtr = OldBuckets; BucketPtr != OldEnd; ++BucketPtr) {
114 // Copy over the element if it is valid.
115 const void *Elt = *BucketPtr;
116 if (Elt != getTombstoneMarker() && Elt != getEmptyMarker())
117 *const_cast<void**>(FindBucketFor(Elt)) = const_cast<void*>(Elt);
118 }
119
120 if (!WasSmall)
121 free(OldBuckets);
122 NumNonEmpty -= NumTombstones;
123 NumTombstones = 0;
124}
125
126SmallPtrSetImplBase::SmallPtrSetImplBase(const void **SmallStorage,
127 const SmallPtrSetImplBase &that) {
128 SmallArray = SmallStorage;
129
130 // If we're becoming small, prepare to insert into our stack space
131 if (that.isSmall()) {
132 CurArray = SmallArray;
133 // Otherwise, allocate new heap space (unless we were the same size)
134 } else {
135 CurArray = (const void**)malloc(sizeof(void*) * that.CurArraySize);
136 if (CurArray == nullptr)
137 report_bad_alloc_error("Allocation of SmallPtrSet bucket array failed.");
138 }
139
140 // Copy over the that array.
141 CopyHelper(that);
142}
143
144SmallPtrSetImplBase::SmallPtrSetImplBase(const void **SmallStorage,
145 unsigned SmallSize,
146 SmallPtrSetImplBase &&that) {
147 SmallArray = SmallStorage;
148 MoveHelper(SmallSize, std::move(that));
149}
150
151void SmallPtrSetImplBase::CopyFrom(const SmallPtrSetImplBase &RHS) {
152 assert(&RHS != this && "Self-copy should be handled by the caller.")((&RHS != this && "Self-copy should be handled by the caller."
) ? static_cast<void> (0) : __assert_fail ("&RHS != this && \"Self-copy should be handled by the caller.\""
, "/build/llvm-toolchain-snapshot-6.0~svn318211/lib/Support/SmallPtrSet.cpp"
, 152, __PRETTY_FUNCTION__))
;
153
154 if (isSmall() && RHS.isSmall())
155 assert(CurArraySize == RHS.CurArraySize &&((CurArraySize == RHS.CurArraySize && "Cannot assign sets with different small sizes"
) ? static_cast<void> (0) : __assert_fail ("CurArraySize == RHS.CurArraySize && \"Cannot assign sets with different small sizes\""
, "/build/llvm-toolchain-snapshot-6.0~svn318211/lib/Support/SmallPtrSet.cpp"
, 156, __PRETTY_FUNCTION__))
156 "Cannot assign sets with different small sizes")((CurArraySize == RHS.CurArraySize && "Cannot assign sets with different small sizes"
) ? static_cast<void> (0) : __assert_fail ("CurArraySize == RHS.CurArraySize && \"Cannot assign sets with different small sizes\""
, "/build/llvm-toolchain-snapshot-6.0~svn318211/lib/Support/SmallPtrSet.cpp"
, 156, __PRETTY_FUNCTION__))
;
157
158 // If we're becoming small, prepare to insert into our stack space
159 if (RHS.isSmall()) {
160 if (!isSmall())
161 free(CurArray);
162 CurArray = SmallArray;
163 // Otherwise, allocate new heap space (unless we were the same size)
164 } else if (CurArraySize != RHS.CurArraySize) {
165 if (isSmall())
166 CurArray = (const void**)malloc(sizeof(void*) * RHS.CurArraySize);
167 else {
168 const void **T = (const void**)realloc(CurArray,
169 sizeof(void*) * RHS.CurArraySize);
170 if (!T)
171 free(CurArray);
172 CurArray = T;
173 }
174 if (CurArray == nullptr)
175 report_bad_alloc_error("Allocation of SmallPtrSet bucket array failed.");
176 }
177
178 CopyHelper(RHS);
179}
180
181void SmallPtrSetImplBase::CopyHelper(const SmallPtrSetImplBase &RHS) {
182 // Copy over the new array size
183 CurArraySize = RHS.CurArraySize;
184
185 // Copy over the contents from the other set
186 std::copy(RHS.CurArray, RHS.EndPointer(), CurArray);
187
188 NumNonEmpty = RHS.NumNonEmpty;
189 NumTombstones = RHS.NumTombstones;
190}
191
192void SmallPtrSetImplBase::MoveFrom(unsigned SmallSize,
193 SmallPtrSetImplBase &&RHS) {
194 if (!isSmall())
195 free(CurArray);
196 MoveHelper(SmallSize, std::move(RHS));
197}
198
199void SmallPtrSetImplBase::MoveHelper(unsigned SmallSize,
200 SmallPtrSetImplBase &&RHS) {
201 assert(&RHS != this && "Self-move should be handled by the caller.")((&RHS != this && "Self-move should be handled by the caller."
) ? static_cast<void> (0) : __assert_fail ("&RHS != this && \"Self-move should be handled by the caller.\""
, "/build/llvm-toolchain-snapshot-6.0~svn318211/lib/Support/SmallPtrSet.cpp"
, 201, __PRETTY_FUNCTION__))
;
202
203 if (RHS.isSmall()) {
204 // Copy a small RHS rather than moving.
205 CurArray = SmallArray;
206 std::copy(RHS.CurArray, RHS.CurArray + RHS.NumNonEmpty, CurArray);
207 } else {
208 CurArray = RHS.CurArray;
209 RHS.CurArray = RHS.SmallArray;
210 }
211
212 // Copy the rest of the trivial members.
213 CurArraySize = RHS.CurArraySize;
214 NumNonEmpty = RHS.NumNonEmpty;
215 NumTombstones = RHS.NumTombstones;
216
217 // Make the RHS small and empty.
218 RHS.CurArraySize = SmallSize;
219 assert(RHS.CurArray == RHS.SmallArray)((RHS.CurArray == RHS.SmallArray) ? static_cast<void> (
0) : __assert_fail ("RHS.CurArray == RHS.SmallArray", "/build/llvm-toolchain-snapshot-6.0~svn318211/lib/Support/SmallPtrSet.cpp"
, 219, __PRETTY_FUNCTION__))
;
220 RHS.NumNonEmpty = 0;
221 RHS.NumTombstones = 0;
222}
223
224void SmallPtrSetImplBase::swap(SmallPtrSetImplBase &RHS) {
225 if (this == &RHS) return;
226
227 // We can only avoid copying elements if neither set is small.
228 if (!this->isSmall() && !RHS.isSmall()) {
229 std::swap(this->CurArray, RHS.CurArray);
230 std::swap(this->CurArraySize, RHS.CurArraySize);
231 std::swap(this->NumNonEmpty, RHS.NumNonEmpty);
232 std::swap(this->NumTombstones, RHS.NumTombstones);
233 return;
234 }
235
236 // FIXME: From here on we assume that both sets have the same small size.
237
238 // If only RHS is small, copy the small elements into LHS and move the pointer
239 // from LHS to RHS.
240 if (!this->isSmall() && RHS.isSmall()) {
241 assert(RHS.CurArray == RHS.SmallArray)((RHS.CurArray == RHS.SmallArray) ? static_cast<void> (
0) : __assert_fail ("RHS.CurArray == RHS.SmallArray", "/build/llvm-toolchain-snapshot-6.0~svn318211/lib/Support/SmallPtrSet.cpp"
, 241, __PRETTY_FUNCTION__))
;
242 std::copy(RHS.CurArray, RHS.CurArray + RHS.NumNonEmpty, this->SmallArray);
243 std::swap(RHS.CurArraySize, this->CurArraySize);
244 std::swap(this->NumNonEmpty, RHS.NumNonEmpty);
245 std::swap(this->NumTombstones, RHS.NumTombstones);
246 RHS.CurArray = this->CurArray;
247 this->CurArray = this->SmallArray;
248 return;
249 }
250
251 // If only LHS is small, copy the small elements into RHS and move the pointer
252 // from RHS to LHS.
253 if (this->isSmall() && !RHS.isSmall()) {
254 assert(this->CurArray == this->SmallArray)((this->CurArray == this->SmallArray) ? static_cast<
void> (0) : __assert_fail ("this->CurArray == this->SmallArray"
, "/build/llvm-toolchain-snapshot-6.0~svn318211/lib/Support/SmallPtrSet.cpp"
, 254, __PRETTY_FUNCTION__))
;
255 std::copy(this->CurArray, this->CurArray + this->NumNonEmpty,
256 RHS.SmallArray);
257 std::swap(RHS.CurArraySize, this->CurArraySize);
258 std::swap(RHS.NumNonEmpty, this->NumNonEmpty);
259 std::swap(RHS.NumTombstones, this->NumTombstones);
260 this->CurArray = RHS.CurArray;
261 RHS.CurArray = RHS.SmallArray;
262 return;
263 }
264
265 // Both a small, just swap the small elements.
266 assert(this->isSmall() && RHS.isSmall())((this->isSmall() && RHS.isSmall()) ? static_cast<
void> (0) : __assert_fail ("this->isSmall() && RHS.isSmall()"
, "/build/llvm-toolchain-snapshot-6.0~svn318211/lib/Support/SmallPtrSet.cpp"
, 266, __PRETTY_FUNCTION__))
;
267 unsigned MinNonEmpty = std::min(this->NumNonEmpty, RHS.NumNonEmpty);
268 std::swap_ranges(this->SmallArray, this->SmallArray + MinNonEmpty,
269 RHS.SmallArray);
270 if (this->NumNonEmpty > MinNonEmpty) {
271 std::copy(this->SmallArray + MinNonEmpty,
272 this->SmallArray + this->NumNonEmpty,
273 RHS.SmallArray + MinNonEmpty);
274 } else {
275 std::copy(RHS.SmallArray + MinNonEmpty, RHS.SmallArray + RHS.NumNonEmpty,
276 this->SmallArray + MinNonEmpty);
277 }
278 assert(this->CurArraySize == RHS.CurArraySize)((this->CurArraySize == RHS.CurArraySize) ? static_cast<
void> (0) : __assert_fail ("this->CurArraySize == RHS.CurArraySize"
, "/build/llvm-toolchain-snapshot-6.0~svn318211/lib/Support/SmallPtrSet.cpp"
, 278, __PRETTY_FUNCTION__))
;
279 std::swap(this->NumNonEmpty, RHS.NumNonEmpty);
280 std::swap(this->NumTombstones, RHS.NumTombstones);
281}