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[NFC][lsan] Use hash table to track root regions

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This avoid O(N) in __lsan_unregister_root_region.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D151784
This commit is contained in:
Vitaly Buka 2023-05-31 00:08:02 -07:00
parent 0375a2dc7d
commit 99dc68387b
1 changed files with 26 additions and 14 deletions
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38
compiler-rt/lib/lsan/lsan_common.cpp
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@ -241,8 +241,6 @@ static LeakSuppressionContext *GetSuppressionContext() {
return suppression_ctx;
}
static InternalMmapVectorNoCtor<Region> root_regions;
void InitCommonLsan() {
if (common_flags()->detect_leaks) {
// Initialization which can fail or print warnings should only be done if
@ -523,15 +521,33 @@ static void ProcessThreads(SuspendedThreadsList const &suspended_threads,
# endif // SANITIZER_FUCHSIA
bool HasRootRegions() { return !root_regions.empty(); }
// A map that contains [region_begin, region_end) pairs.
using RootRegions = DenseMap<detail::DenseMapPair<uptr, uptr>, uptr>;
static RootRegions &GetRootRegionsLocked() {
global_mutex.CheckLocked();
static RootRegions *regions = nullptr;
alignas(RootRegions) static char placeholder[sizeof(RootRegions)];
if (!regions)
regions = new (placeholder) RootRegions();
return *regions;
}
bool HasRootRegions() { return !GetRootRegionsLocked().empty(); }
void ScanRootRegions(Frontier *frontier,
const InternalMmapVectorNoCtor<Region> &mapped_regions) {
if (!flags()->use_root_regions)
return;
InternalMmapVector<Region> regions;
GetRootRegionsLocked().forEach([&](const auto &kv) {
regions.push_back({kv.first.first, kv.first.second});
return true;
});
InternalMmapVector<Region> intersection;
Intersect(mapped_regions, root_regions, intersection);
Intersect(mapped_regions, regions, intersection);
for (const Region &r : intersection) {
LOG_POINTERS("Root region intersects with mapped region at %p-%p\n",
@ -1011,7 +1027,7 @@ void __lsan_register_root_region(const void *begin, uptr size) {
CHECK_LT(b, e);
Lock l(&global_mutex);
root_regions.push_back({b, e});
++GetRootRegionsLocked()[{b, e}];
#endif // CAN_SANITIZE_LEAKS
}
@ -1021,20 +1037,16 @@ void __lsan_unregister_root_region(const void *begin, uptr size) {
uptr b = reinterpret_cast<uptr>(begin);
uptr e = b + size;
CHECK_LT(b, e);
VReport(1, "Unregistered root region at %p of size %zu\n", begin, size);
{
Lock l(&global_mutex);
for (uptr i = 0; i < root_regions.size(); i++) {
Region region = root_regions[i];
if (region.begin == b && region.end == e) {
uptr last_index = root_regions.size() - 1;
root_regions[i] = root_regions[last_index];
root_regions.pop_back();
VReport(1, "Unregistered root region at %p of size %zu\n", begin, size);
if (auto *f = GetRootRegionsLocked().find({b, e})) {
if (--(f->second) == 0)
GetRootRegionsLocked().erase(f);
return;
}
}
}
Report(
"__lsan_unregister_root_region(): region at %p of size %zu has not "
"been registered.\n",