static void
GetChromeHangReport(Telemetry::HangStack &callStack, SharedLibraryInfo &moduleMap)
{
MOZ_ASSERT(winMainThreadHandle);
DWORD ret = ::SuspendThread(winMainThreadHandle);
if (ret == -1) {
callStack.Clear();
moduleMap.Clear();
return;
}
NS_StackWalk(ChromeStackWalker, 0, &callStack,
reinterpret_cast<uintptr_t>(winMainThreadHandle));
ret = ::ResumeThread(winMainThreadHandle);
if (ret == -1) {
callStack.Clear();
moduleMap.Clear();
return;
}
moduleMap = SharedLibraryInfo::GetInfoForSelf();
moduleMap.SortByAddress();
// Remove all modules not referenced by a PC on the stack
Telemetry::HangStack sortedStack = callStack;
sortedStack.Sort();
size_t moduleIndex = 0;
size_t stackIndex = 0;
bool unreferencedModule = true;
while (stackIndex < sortedStack.Length() && moduleIndex < moduleMap.GetSize()) {
uintptr_t pc = sortedStack[stackIndex];
SharedLibrary& module = moduleMap.GetEntry(moduleIndex);
uintptr_t moduleStart = module.GetStart();
uintptr_t moduleEnd = module.GetEnd() - 1;
if (moduleStart <= pc && pc <= moduleEnd) {
// If the current PC is within the current module, mark module as used
unreferencedModule = false;
++stackIndex;
} else if (pc > moduleEnd) {
if (unreferencedModule) {
// Remove module if no PCs within its address range
moduleMap.RemoveEntries(moduleIndex, moduleIndex + 1);
} else {
// Module was referenced on stack, but current PC belongs to later module
unreferencedModule = true;
++moduleIndex;
}
} else {
// PC does not belong to any module
++stackIndex;
}
}
// Clean up remaining unreferenced modules, i.e. module addresses > max(pc)
if (moduleIndex + 1 < moduleMap.GetSize()) {
moduleMap.RemoveEntries(moduleIndex + 1, moduleMap.GetSize());
}
}
void
TelemetryImpl::RecordChromeHang(uint32_t duration,
const Telemetry::HangStack &callStack,
SharedLibraryInfo &moduleMap)
{
MOZ_ASSERT(sTelemetry);
if (!sTelemetry->mCanRecord) {
return;
}
MutexAutoLock hangReportMutex(sTelemetry->mHangReportsMutex);
// Only report the modules which changed since the first hang report
if (sTelemetry->mHangReports.Length()) {
SharedLibraryInfo &firstModuleMap =
sTelemetry->mHangReports[0].moduleMap;
for (size_t i = 0; i < moduleMap.GetSize(); ++i) {
if (firstModuleMap.Contains(moduleMap.GetEntry(i))) {
moduleMap.RemoveEntries(i, i + 1);
--i;
}
}
}
HangReport newReport = { duration, callStack, moduleMap };
sTelemetry->mHangReports.AppendElement(newReport);
}