[llvm] r236741 - Fix another hang caused by ManagedStatic in SignalHandler

[Steven Wu]

Author: steven_wu
Date: Thu May  7 11:20:51 2015
New Revision: 236741

URL: http://llvm.org/viewvc/llvm-project?rev=236741&view=rev
Log:
Fix another hang caused by ManagedStatic in SignalHandler

Fix two other variables that might cause the same hang fixed in r235914.
The hang is caused by constructing ManagedStatic in signalhandler. In
this case, if FileToRemove or CallBacksToRun is not contructed, it means
there is no work to do.

Modified:
    llvm/trunk/lib/Support/Unix/Signals.inc

Modified: llvm/trunk/lib/Support/Unix/Signals.inc
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Unix/Signals.inc?rev=236741&r1=236740&r2=236741&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Unix/Signals.inc (original)
+++ llvm/trunk/lib/Support/Unix/Signals.inc Thu May  7 11:20:51 2015
@@ -139,6 +139,11 @@ static void UnregisterHandlers() {
 /// NB: This must be an async signal safe function. It cannot allocate or free
 /// memory, even in debug builds.
 static void RemoveFilesToRemove() {
+  // Avoid constructing ManagedStatic in the signal handler.
+  // If FilesToRemove is not constructed, there are no files to remove.
+  if (!FilesToRemove.isConstructed())
+    return;
+
   // We avoid iterators in case of debug iterators that allocate or release
   // memory.
   std::vector<std::string>& FilesToRemoveRef = *FilesToRemove;
@@ -200,10 +205,12 @@ static RETSIGTYPE SignalHandler(int Sig)
   }
 
   // Otherwise if it is a fault (like SEGV) run any handler.
-  std::vector<std::pair<void (*)(void *), void *>>& CallBacksToRunRef =
-      *CallBacksToRun;
-  for (unsigned i = 0, e = CallBacksToRun->size(); i != e; ++i)
-    CallBacksToRunRef[i].first(CallBacksToRunRef[i].second);
+  if (CallBacksToRun.isConstructed()) {
+    std::vector<std::pair<void (*)(void *), void *>>& CallBacksToRunRef =
+        *CallBacksToRun;
+    for (unsigned i = 0, e = CallBacksToRun->size(); i != e; ++i)
+      CallBacksToRunRef[i].first(CallBacksToRunRef[i].second);
+  }
 
 #ifdef __s390__
   // On S/390, certain signals are delivered with PSW Address pointing to