[compiler-rt] r308999 - Only scan global sections containing data in LSan on darwin
Francis Ricci via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 25 11:16:58 PDT 2017
Author: fjricci
Date: Tue Jul 25 11:16:58 2017
New Revision: 308999
URL: http://llvm.org/viewvc/llvm-project?rev=308999&view=rev
Log:
Only scan global sections containing data in LSan on darwin
Summary:
__DATA segments on Darwin contain a large number of separate sections,
many of which cannot actually contain pointers, and contain const values or
objc metadata. Not scanning sections which cannot contain pointers significantly
improves performance.
On a medium-sized (~4000 files) internal project, I saw a speedup of about 30%
in standalone LSan's execution time (30% improvement in the time spent running
LSan, not the total program time).
Reviewers: kcc, kubamracek, alekseyshl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D35432
Modified:
compiler-rt/trunk/lib/lsan/lsan_common_mac.cc
compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc
compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h
compiler-rt/trunk/lib/sanitizer_common/sanitizer_procmaps_mac.cc
Modified: compiler-rt/trunk/lib/lsan/lsan_common_mac.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/lsan/lsan_common_mac.cc?rev=308999&r1=308998&r2=308999&view=diff
==============================================================================
--- compiler-rt/trunk/lib/lsan/lsan_common_mac.cc (original)
+++ compiler-rt/trunk/lib/lsan/lsan_common_mac.cc Tue Jul 25 11:16:58 2017
@@ -92,8 +92,25 @@ LoadedModule *GetLinker() { return nullp
// required on Darwin.
void InitializePlatformSpecificModules() {}
+// Sections which can't contain contain global pointers. This list errs on the
+// side of caution to avoid false positives, at the expense of performance.
+//
+// Other potentially safe sections include:
+// __all_image_info, __crash_info, __const, __got, __interpose, __objc_msg_break
+//
+// Sections which definitely cannot be included here are:
+// __objc_data, __objc_const, __data, __bss, __common, __thread_data,
+// __thread_bss, __thread_vars, __objc_opt_rw, __objc_opt_ptrs
+static const char *kSkippedSecNames[] = {
+ "__cfstring", "__la_symbol_ptr", "__mod_init_func",
+ "__mod_term_func", "__nl_symbol_ptr", "__objc_classlist",
+ "__objc_classrefs", "__objc_imageinfo", "__objc_nlclslist",
+ "__objc_protolist", "__objc_selrefs", "__objc_superrefs"};
+
// Scans global variables for heap pointers.
void ProcessGlobalRegions(Frontier *frontier) {
+ for (auto name : kSkippedSecNames) CHECK(ARRAY_SIZE(name) < kMaxSegName);
+
MemoryMappingLayout memory_mapping(false);
InternalMmapVector<LoadedModule> modules(/*initial_capacity*/ 128);
memory_mapping.DumpListOfModules(&modules);
@@ -107,6 +124,10 @@ void ProcessGlobalRegions(Frontier *fron
// Sections storing global variables are writable and non-executable
if (range.executable || !range.writable) continue;
+ for (auto name : kSkippedSecNames) {
+ if (!internal_strcmp(range.name, name)) continue;
+ }
+
ScanGlobalRange(range.beg, range.end, frontier);
}
}
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc?rev=308999&r1=308998&r2=308999&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.cc Tue Jul 25 11:16:58 2017
@@ -183,9 +183,10 @@ void LoadedModule::clear() {
}
void LoadedModule::addAddressRange(uptr beg, uptr end, bool executable,
- bool writable) {
+ bool writable, const char *name) {
void *mem = InternalAlloc(sizeof(AddressRange));
- AddressRange *r = new(mem) AddressRange(beg, end, executable, writable);
+ AddressRange *r =
+ new(mem) AddressRange(beg, end, executable, writable, name);
ranges_.push_back(r);
if (executable && end > max_executable_address_)
max_executable_address_ = end;
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h?rev=308999&r1=308998&r2=308999&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common.h Tue Jul 25 11:16:58 2017
@@ -624,6 +624,7 @@ inline const char *ModuleArchToString(Mo
}
const uptr kModuleUUIDSize = 16;
+const uptr kMaxSegName = 16;
// Represents a binary loaded into virtual memory (e.g. this can be an
// executable or a shared object).
@@ -642,7 +643,8 @@ class LoadedModule {
void set(const char *module_name, uptr base_address, ModuleArch arch,
u8 uuid[kModuleUUIDSize], bool instrumented);
void clear();
- void addAddressRange(uptr beg, uptr end, bool executable, bool writable);
+ void addAddressRange(uptr beg, uptr end, bool executable, bool writable,
+ const char *name = nullptr);
bool containsAddress(uptr address) const;
const char *full_name() const { return full_name_; }
@@ -658,13 +660,17 @@ class LoadedModule {
uptr end;
bool executable;
bool writable;
+ char name[kMaxSegName];
- AddressRange(uptr beg, uptr end, bool executable, bool writable)
+ AddressRange(uptr beg, uptr end, bool executable, bool writable,
+ const char *name)
: next(nullptr),
beg(beg),
end(end),
executable(executable),
- writable(writable) {}
+ writable(writable) {
+ internal_strncpy(this->name, (name ? name : ""), ARRAY_SIZE(this->name));
+ }
};
const IntrusiveList<AddressRange> &ranges() const { return ranges_; }
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_procmaps_mac.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_procmaps_mac.cc?rev=308999&r1=308998&r2=308999&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_procmaps_mac.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_procmaps_mac.cc Tue Jul 25 11:16:58 2017
@@ -38,6 +38,7 @@ namespace __sanitizer {
// Contains information used to iterate through sections.
struct MemoryMappedSegmentData {
+ char name[kMaxSegName];
uptr nsects;
char *current_load_cmd_addr;
u32 lc_type;
@@ -53,7 +54,8 @@ static void NextSectionLoad(LoadedModule
uptr sec_start = (sc->addr & data->addr_mask) + data->base_virt_addr;
uptr sec_end = sec_start + sc->size;
- module->addAddressRange(sec_start, sec_end, /*executable=*/false, isWritable);
+ module->addAddressRange(sec_start, sec_end, /*executable=*/false, isWritable,
+ sc->sectname);
}
void MemoryMappedSegment::AddAddressRanges(LoadedModule *module) {
@@ -63,7 +65,8 @@ void MemoryMappedSegment::AddAddressRang
// it will confuse libignore, and because the extra granularity
// of information is not needed by any sanitizers.
if (!data_ || !data_->nsects || IsExecutable()) {
- module->addAddressRange(start, end, IsExecutable(), IsWritable());
+ module->addAddressRange(start, end, IsExecutable(), IsWritable(),
+ data_ ? data_->name : nullptr);
return;
}
@@ -212,6 +215,8 @@ bool MemoryMappingLayout::NextSegmentLoa
segment->data_->lc_type = kLCSegment;
segment->data_->base_virt_addr = base_virt_addr;
segment->data_->addr_mask = addr_mask;
+ internal_strncpy(segment->data_->name, sc->segname,
+ ARRAY_SIZE(segment->data_->name));
}
// Return the initial protection.
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