[llvm] r188216 - DataFlowSanitizer: fix a use-after-free. Spotted by libgmalloc.

[Peter Collingbourne]

Author: pcc
Date: Mon Aug 12 17:38:39 2013
New Revision: 188216

URL: http://llvm.org/viewvc/llvm-project?rev=188216&view=rev
Log:
DataFlowSanitizer: fix a use-after-free.  Spotted by libgmalloc.

Modified:
    llvm/trunk/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp

Modified: llvm/trunk/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp?rev=188216&r1=188215&r2=188216&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp Mon Aug 12 17:38:39 2013
@@ -422,9 +422,12 @@ bool DataFlowSanitizer::runOnModule(Modu
         // instruction's next pointer and moving the next instruction to the
         // tail block from which we should continue.
         Instruction *Next = Inst->getNextNode();
+        // DFSanVisitor may delete Inst, so keep track of whether it was a
+        // terminator.
+        bool IsTerminator = isa<TerminatorInst>(Inst);
         if (!DFSF.SkipInsts.count(Inst))
           DFSanVisitor(DFSF).visit(Inst);
-        if (isa<TerminatorInst>(Inst))
+        if (IsTerminator)
           break;
         Inst = Next;
       }