Fix a crash that happens when mapping something like this:

 { short, short }

to
  short

where the second short maps onto the second field of the first struct.  In
this case, the struct index is not aligned, so we should avoid calling
getLink(2), which asserts out.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20626 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/DataStructure/DataStructure.cpp b/lib/Analysis/DataStructure/DataStructure.cpp
index 21e18a6b74dab00758507163f3e9d9c2ab89c553..69b3da43dfc56a74f73746ed7a64a850f0080a3a 100644 (file)
--- a/lib/Analysis/DataStructure/DataStructure.cpp
+++ b/lib/Analysis/DataStructure/DataStructure.cpp
@@ -2077,12 +2077,18 @@ void DSGraph::computeNodeMapping(const DSNodeHandle &NH1,
   unsigned N2Size = N2->getSize();
   if (N2Size == 0) return;   // No edges to map to.
 
-  for (unsigned i = 0, e = N1->getSize(); i < e; i += DS::PointerSize)
-    if (unsigned(N2Idx)+i < N2Size)
-      computeNodeMapping(N1->getLink(i), N2->getLink(N2Idx+i), NodeMap);
-    else
-      computeNodeMapping(N1->getLink(i),
-                         N2->getLink(unsigned(N2Idx+i) % N2Size), NodeMap);
+  for (unsigned i = 0, e = N1->getSize(); i < e; i += DS::PointerSize) {
+    const DSNodeHandle &N1NH = N1->getLink(i);
+    // Don't call N2->getLink if not needed (avoiding crash if N2Idx is not
+    // aligned right).
+    if (!N1NH.isNull()) {
+      if (unsigned(N2Idx)+i < N2Size)
+        computeNodeMapping(N1NH, N2->getLink(N2Idx+i), NodeMap);
+      else
+        computeNodeMapping(N1NH,
+                           N2->getLink(unsigned(N2Idx+i) % N2Size), NodeMap);
+    }
+  }
 }