[llvm] r265639 - Fix the sanitizer bootstrap error in r265547.

[Wei Mi via llvm-commits]

Author: wmi
Date: Thu Apr  7 00:27:17 2016
New Revision: 265639

URL: http://llvm.org/viewvc/llvm-project?rev=265639&view=rev
Log:
Fix the sanitizer bootstrap error in r265547.

The iterators of SmallPtrSet SpillsInSubTreeMap[Child].first may be
invalidated when SpillsInSubTreeMap grows. Rearrange the code to
ensure the grow of SpillsInSubTreeMap only happens before getting
the iterators of the SmallPtrSet.


Modified:
    llvm/trunk/lib/CodeGen/InlineSpiller.cpp

Modified: llvm/trunk/lib/CodeGen/InlineSpiller.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/InlineSpiller.cpp?rev=265639&r1=265638&r2=265639&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/InlineSpiller.cpp (original)
+++ llvm/trunk/lib/CodeGen/InlineSpiller.cpp Thu Apr  7 00:27:17 2016
@@ -1272,10 +1272,17 @@ void HoistSpillHelper::runHoistSpills(
     unsigned NumChildren = Children.size();
     for (unsigned i = 0; i != NumChildren; ++i) {
       MachineDomTreeNode *Child = Children[i];
+      if (SpillsInSubTreeMap.find(Child) == SpillsInSubTreeMap.end())
+        continue;
+      // SpillsInSubTreeMap[*RIt].second += SpillsInSubTreeMap[Child].second
+      // should be placed before getting the begin and end iterators of
+      // SpillsInSubTreeMap[Child].first, or else the iterators may be
+      // invalidated when SpillsInSubTreeMap[*RIt] is seen the first time
+      // and the map grows and then the original buckets in the map are moved.
+      SpillsInSubTreeMap[*RIt].second += SpillsInSubTreeMap[Child].second;
       auto BI = SpillsInSubTreeMap[Child].first.begin();
       auto EI = SpillsInSubTreeMap[Child].first.end();
       SpillsInSubTreeMap[*RIt].first.insert(BI, EI);
-      SpillsInSubTreeMap[*RIt].second += SpillsInSubTreeMap[Child].second;
       SpillsInSubTreeMap.erase(Child);
     }