Bug Summary

File:tools/clang/lib/AST/RawCommentList.cpp
Warning:line 195, column 3
Null pointer passed as an argument to a 'nonnull' parameter

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name RawCommentList.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-eagerly-assume -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 -mrelocation-model pic -pic-level 2 -mthread-model posix -relaxed-aliasing -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-7/lib/clang/7.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-7~svn326246/build-llvm/tools/clang/lib/AST -I /build/llvm-toolchain-snapshot-7~svn326246/tools/clang/lib/AST -I /build/llvm-toolchain-snapshot-7~svn326246/tools/clang/include -I /build/llvm-toolchain-snapshot-7~svn326246/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-7~svn326246/build-llvm/include -I /build/llvm-toolchain-snapshot-7~svn326246/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0/backward -internal-isystem /usr/include/clang/7.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-7/lib/clang/7.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-7~svn326246/build-llvm/tools/clang/lib/AST -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -fobjc-runtime=gcc -fno-common -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-checker optin.performance.Padding -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-02-28-041547-14988-1 -x c++ /build/llvm-toolchain-snapshot-7~svn326246/tools/clang/lib/AST/RawCommentList.cpp
1//===--- RawCommentList.cpp - Processing raw comments -----------*- C++ -*-===//
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#include "clang/AST/RawCommentList.h"
11#include "clang/AST/ASTContext.h"
12#include "clang/AST/Comment.h"
13#include "clang/AST/CommentBriefParser.h"
14#include "clang/AST/CommentCommandTraits.h"
15#include "clang/AST/CommentLexer.h"
16#include "clang/AST/CommentParser.h"
17#include "clang/AST/CommentSema.h"
18#include "clang/Basic/CharInfo.h"
19#include "llvm/ADT/STLExtras.h"
20
21using namespace clang;
22
23namespace {
24/// Get comment kind and bool describing if it is a trailing comment.
25std::pair<RawComment::CommentKind, bool> getCommentKind(StringRef Comment,
26 bool ParseAllComments) {
27 const size_t MinCommentLength = ParseAllComments ? 2 : 3;
28 if ((Comment.size() < MinCommentLength) || Comment[0] != '/')
29 return std::make_pair(RawComment::RCK_Invalid, false);
30
31 RawComment::CommentKind K;
32 if (Comment[1] == '/') {
33 if (Comment.size() < 3)
34 return std::make_pair(RawComment::RCK_OrdinaryBCPL, false);
35
36 if (Comment[2] == '/')
37 K = RawComment::RCK_BCPLSlash;
38 else if (Comment[2] == '!')
39 K = RawComment::RCK_BCPLExcl;
40 else
41 return std::make_pair(RawComment::RCK_OrdinaryBCPL, false);
42 } else {
43 assert(Comment.size() >= 4)(static_cast <bool> (Comment.size() >= 4) ? void (0)
: __assert_fail ("Comment.size() >= 4", "/build/llvm-toolchain-snapshot-7~svn326246/tools/clang/lib/AST/RawCommentList.cpp"
, 43, __extension__ __PRETTY_FUNCTION__));
44
45 // Comment lexer does not understand escapes in comment markers, so pretend
46 // that this is not a comment.
47 if (Comment[1] != '*' ||
48 Comment[Comment.size() - 2] != '*' ||
49 Comment[Comment.size() - 1] != '/')
50 return std::make_pair(RawComment::RCK_Invalid, false);
51
52 if (Comment[2] == '*')
53 K = RawComment::RCK_JavaDoc;
54 else if (Comment[2] == '!')
55 K = RawComment::RCK_Qt;
56 else
57 return std::make_pair(RawComment::RCK_OrdinaryC, false);
58 }
59 const bool TrailingComment = (Comment.size() > 3) && (Comment[3] == '<');
60 return std::make_pair(K, TrailingComment);
61}
62
63bool mergedCommentIsTrailingComment(StringRef Comment) {
64 return (Comment.size() > 3) && (Comment[3] == '<');
65}
66
67/// Returns true if R1 and R2 both have valid locations that start on the same
68/// column.
69bool commentsStartOnSameColumn(const SourceManager &SM, const RawComment &R1,
70 const RawComment &R2) {
71 SourceLocation L1 = R1.getLocStart();
72 SourceLocation L2 = R2.getLocStart();
73 bool Invalid = false;
74 unsigned C1 = SM.getPresumedColumnNumber(L1, &Invalid);
75 if (!Invalid) {
76 unsigned C2 = SM.getPresumedColumnNumber(L2, &Invalid);
77 return !Invalid && (C1 == C2);
78 }
79 return false;
80}
81} // unnamed namespace
82
83/// \brief Determines whether there is only whitespace in `Buffer` between `P`
84/// and the previous line.
85/// \param Buffer The buffer to search in.
86/// \param P The offset from the beginning of `Buffer` to start from.
87/// \return true if all of the characters in `Buffer` ranging from the closest
88/// line-ending character before `P` (or the beginning of `Buffer`) to `P - 1`
89/// are whitespace.
90static bool onlyWhitespaceOnLineBefore(const char *Buffer, unsigned P) {
91 // Search backwards until we see linefeed or carriage return.
92 for (unsigned I = P; I != 0; --I) {
93 char C = Buffer[I - 1];
94 if (isVerticalWhitespace(C))
95 return true;
96 if (!isHorizontalWhitespace(C))
97 return false;
98 }
99 // We hit the beginning of the buffer.
100 return true;
101}
102
103/// Returns whether `K` is an ordinary comment kind.
104static bool isOrdinaryKind(RawComment::CommentKind K) {
105 return (K == RawComment::RCK_OrdinaryBCPL) ||
106 (K == RawComment::RCK_OrdinaryC);
107}
108
109RawComment::RawComment(const SourceManager &SourceMgr, SourceRange SR,
110 bool Merged, bool ParseAllComments) :
111 Range(SR), RawTextValid(false), BriefTextValid(false),
112 IsAttached(false), IsTrailingComment(false), IsAlmostTrailingComment(false),
113 ParseAllComments(ParseAllComments) {
114 // Extract raw comment text, if possible.
115 if (SR.getBegin() == SR.getEnd() || getRawText(SourceMgr).empty()) {
116 Kind = RCK_Invalid;
117 return;
118 }
119
120 // Guess comment kind.
121 std::pair<CommentKind, bool> K = getCommentKind(RawText, ParseAllComments);
122
123 // Guess whether an ordinary comment is trailing.
124 if (ParseAllComments && isOrdinaryKind(K.first)) {
125 FileID BeginFileID;
126 unsigned BeginOffset;
127 std::tie(BeginFileID, BeginOffset) =
128 SourceMgr.getDecomposedLoc(Range.getBegin());
129 if (BeginOffset != 0) {
130 bool Invalid = false;
131 const char *Buffer =
132 SourceMgr.getBufferData(BeginFileID, &Invalid).data();
133 IsTrailingComment |=
134 (!Invalid && !onlyWhitespaceOnLineBefore(Buffer, BeginOffset));
135 }
136 }
137
138 if (!Merged) {
139 Kind = K.first;
140 IsTrailingComment |= K.second;
141
142 IsAlmostTrailingComment = RawText.startswith("//<") ||
143 RawText.startswith("/*<");
144 } else {
145 Kind = RCK_Merged;
146 IsTrailingComment =
147 IsTrailingComment || mergedCommentIsTrailingComment(RawText);
148 }
149}
150
151StringRef RawComment::getRawTextSlow(const SourceManager &SourceMgr) const {
152 FileID BeginFileID;
153 FileID EndFileID;
154 unsigned BeginOffset;
155 unsigned EndOffset;
156
157 std::tie(BeginFileID, BeginOffset) =
158 SourceMgr.getDecomposedLoc(Range.getBegin());
159 std::tie(EndFileID, EndOffset) = SourceMgr.getDecomposedLoc(Range.getEnd());
160
161 const unsigned Length = EndOffset - BeginOffset;
162 if (Length < 2)
163 return StringRef();
164
165 // The comment can't begin in one file and end in another.
166 assert(BeginFileID == EndFileID)(static_cast <bool> (BeginFileID == EndFileID) ? void (
0) : __assert_fail ("BeginFileID == EndFileID", "/build/llvm-toolchain-snapshot-7~svn326246/tools/clang/lib/AST/RawCommentList.cpp"
, 166, __extension__ __PRETTY_FUNCTION__));
167
168 bool Invalid = false;
169 const char *BufferStart = SourceMgr.getBufferData(BeginFileID,
170 &Invalid).data();
171 if (Invalid)
172 return StringRef();
173
174 return StringRef(BufferStart + BeginOffset, Length);
175}
176
177const char *RawComment::extractBriefText(const ASTContext &Context) const {
178 // Lazily initialize RawText using the accessor before using it.
179 (void)getRawText(Context.getSourceManager());
180
181 // Since we will be copying the resulting text, all allocations made during
182 // parsing are garbage after resulting string is formed. Thus we can use
183 // a separate allocator for all temporary stuff.
184 llvm::BumpPtrAllocator Allocator;
185
186 comments::Lexer L(Allocator, Context.getDiagnostics(),
187 Context.getCommentCommandTraits(),
188 Range.getBegin(),
189 RawText.begin(), RawText.end());
190 comments::BriefParser P(L, Context.getCommentCommandTraits());
191
192 const std::string Result = P.Parse();
193 const unsigned BriefTextLength = Result.size();
194 char *BriefTextPtr = new (Context) char[BriefTextLength + 1];
1
'BriefTextPtr' initialized to a null pointer value
→
195 memcpy(BriefTextPtr, Result.c_str(), BriefTextLength + 1);
2
←
Null pointer passed as an argument to a 'nonnull' parameter
196 BriefText = BriefTextPtr;
197 BriefTextValid = true;
198
199 return BriefTextPtr;
200}
201
202comments::FullComment *RawComment::parse(const ASTContext &Context,
203 const Preprocessor *PP,
204 const Decl *D) const {
205 // Lazily initialize RawText using the accessor before using it.
206 (void)getRawText(Context.getSourceManager());
207
208 comments::Lexer L(Context.getAllocator(), Context.getDiagnostics(),
209 Context.getCommentCommandTraits(),
210 getSourceRange().getBegin(),
211 RawText.begin(), RawText.end());
212 comments::Sema S(Context.getAllocator(), Context.getSourceManager(),
213 Context.getDiagnostics(),
214 Context.getCommentCommandTraits(),
215 PP);
216 S.setDecl(D);
217 comments::Parser P(L, S, Context.getAllocator(), Context.getSourceManager(),
218 Context.getDiagnostics(),
219 Context.getCommentCommandTraits());
220
221 return P.parseFullComment();
222}
223
224static bool onlyWhitespaceBetween(SourceManager &SM,
225 SourceLocation Loc1, SourceLocation Loc2,
226 unsigned MaxNewlinesAllowed) {
227 std::pair<FileID, unsigned> Loc1Info = SM.getDecomposedLoc(Loc1);
228 std::pair<FileID, unsigned> Loc2Info = SM.getDecomposedLoc(Loc2);
229
230 // Question does not make sense if locations are in different files.
231 if (Loc1Info.first != Loc2Info.first)
232 return false;
233
234 bool Invalid = false;
235 const char *Buffer = SM.getBufferData(Loc1Info.first, &Invalid).data();
236 if (Invalid)
237 return false;
238
239 unsigned NumNewlines = 0;
240 assert(Loc1Info.second <= Loc2Info.second && "Loc1 after Loc2!")(static_cast <bool> (Loc1Info.second <= Loc2Info.second
&& "Loc1 after Loc2!") ? void (0) : __assert_fail ("Loc1Info.second <= Loc2Info.second && \"Loc1 after Loc2!\""
, "/build/llvm-toolchain-snapshot-7~svn326246/tools/clang/lib/AST/RawCommentList.cpp"
, 240, __extension__ __PRETTY_FUNCTION__));
241 // Look for non-whitespace characters and remember any newlines seen.
242 for (unsigned I = Loc1Info.second; I != Loc2Info.second; ++I) {
243 switch (Buffer[I]) {
244 default:
245 return false;
246 case ' ':
247 case '\t':
248 case '\f':
249 case '\v':
250 break;
251 case '\r':
252 case '\n':
253 ++NumNewlines;
254
255 // Check if we have found more than the maximum allowed number of
256 // newlines.
257 if (NumNewlines > MaxNewlinesAllowed)
258 return false;
259
260 // Collapse \r\n and \n\r into a single newline.
261 if (I + 1 != Loc2Info.second &&
262 (Buffer[I + 1] == '\n' || Buffer[I + 1] == '\r') &&
263 Buffer[I] != Buffer[I + 1])
264 ++I;
265 break;
266 }
267 }
268
269 return true;
270}
271
272void RawCommentList::addComment(const RawComment &RC,
273 llvm::BumpPtrAllocator &Allocator) {
274 if (RC.isInvalid())
275 return;
276
277 // Check if the comments are not in source order.
278 while (!Comments.empty() &&
279 !SourceMgr.isBeforeInTranslationUnit(Comments.back()->getLocStart(),
280 RC.getLocStart())) {
281 // If they are, just pop a few last comments that don't fit.
282 // This happens if an \#include directive contains comments.
283 Comments.pop_back();
284 }
285
286 // Ordinary comments are not interesting for us.
287 if (RC.isOrdinary())
288 return;
289
290 // If this is the first Doxygen comment, save it (because there isn't
291 // anything to merge it with).
292 if (Comments.empty()) {
293 Comments.push_back(new (Allocator) RawComment(RC));
294 return;
295 }
296
297 const RawComment &C1 = *Comments.back();
298 const RawComment &C2 = RC;
299
300 // Merge comments only if there is only whitespace between them.
301 // Can't merge trailing and non-trailing comments unless the second is
302 // non-trailing ordinary in the same column, as in the case:
303 // int x; // documents x
304 // // more text
305 // versus:
306 // int x; // documents x
307 // int y; // documents y
308 // or:
309 // int x; // documents x
310 // // documents y
311 // int y;
312 // Merge comments if they are on same or consecutive lines.
313 if ((C1.isTrailingComment() == C2.isTrailingComment() ||
314 (C1.isTrailingComment() && !C2.isTrailingComment() &&
315 isOrdinaryKind(C2.getKind()) &&
316 commentsStartOnSameColumn(SourceMgr, C1, C2))) &&
317 onlyWhitespaceBetween(SourceMgr, C1.getLocEnd(), C2.getLocStart(),
318 /*MaxNewlinesAllowed=*/1)) {
319 SourceRange MergedRange(C1.getLocStart(), C2.getLocEnd());
320 *Comments.back() = RawComment(SourceMgr, MergedRange, true,
321 RC.isParseAllComments());
322 } else {
323 Comments.push_back(new (Allocator) RawComment(RC));
324 }
325}
326
327void RawCommentList::addDeserializedComments(ArrayRef<RawComment *> DeserializedComments) {
328 std::vector<RawComment *> MergedComments;
329 MergedComments.reserve(Comments.size() + DeserializedComments.size());
330
331 std::merge(Comments.begin(), Comments.end(),
332 DeserializedComments.begin(), DeserializedComments.end(),
333 std::back_inserter(MergedComments),
334 BeforeThanCompare<RawComment>(SourceMgr));
335 std::swap(Comments, MergedComments);
336}