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author | Kostya Kortchinsky <kostyak@google.com> | 2017-08-21 21:25:38 +0000 |
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committer | Kostya Kortchinsky <kostyak@google.com> | 2017-08-21 21:25:38 +0000 |
commit | bcdd70fe3bcf63a5e675d6070e9c86dd9becc9ff (patch) | |
tree | 3ea44e68b6b512441a891c4da2cd5bad8a2b8b24 /lib/sanitizer_common/sanitizer_flag_parser.h | |
parent | 916b56d6d731c57374e2635abaa39cdc3e8ff129 (diff) |
[sanitizer] Do not over-dup string flags
Summary:
String flags values appear to be duped twice. Once in `FlagParser::parse_flag`
using the `LowLevelAllocator` via `ll_strndup`, once in
`FlagHandler<const char *>::Parse` using the `InternalAllocator` via
`internal_strdup`. It looks like the second one is redundant, as the memory
for the first one is never freed and not used for anything else.
Assigning the value to the flag instead of duping it has a few advantages:
- if it was the only use of the `InternalAllocator` (which is the case for
Scudo), then the related code will not be compiled it, which saves us a
whole instantiation of the CombinedAllocator worth of extra code;
- in the event a string flag is parsed, the `InternalAllocator` would have
created a whole SizeClassAllocator32 region for a single allocation, which is
kind of wasteful.
- also, the string is dup'ed twice for the whole lifetime of a process.
I tested check-{sanitizer,asan,tsan,ubsan,scudo} successfully, so as far as I
can tell this doesn't appear to have bad side effects.
Reviewers: eugenis, alekseyshl
Reviewed By: eugenis
Subscribers: kubamracek, llvm-commits
Differential Revision: https://reviews.llvm.org/D36970
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@311386 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/sanitizer_common/sanitizer_flag_parser.h')
-rw-r--r-- | lib/sanitizer_common/sanitizer_flag_parser.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/sanitizer_common/sanitizer_flag_parser.h b/lib/sanitizer_common/sanitizer_flag_parser.h index 4988fbb7a..f649f5bff 100644 --- a/lib/sanitizer_common/sanitizer_flag_parser.h +++ b/lib/sanitizer_common/sanitizer_flag_parser.h @@ -75,7 +75,7 @@ inline bool FlagHandler<HandleSignalMode>::Parse(const char *value) { template <> inline bool FlagHandler<const char *>::Parse(const char *value) { - *t_ = internal_strdup(value); + *t_ = value; return true; } |