[llvm-commits] [llvm] r127640 - /llvm/trunk/lib/CodeGen/DwarfEHPrepare.cpp

[Bill Wendling]

Author: void
Date: Mon Mar 14 20:03:17 2011
New Revision: 127640

URL: http://llvm.org/viewvc/llvm-project?rev=127640&view=rev
Log:
There are some situations which can cause the URoR hack to infinitely recurse
and then go kablooie. The problem was that it was tracking the PHI nodes anew
each time into this function. But it didn't need to. And because the recursion
didn't know that a PHINode was visited before, it would go ahead and call
itself.

There is a testcase, but unfortunately it's too big to add. This problem will go
away with the EH rewrite.
<rdar://problem/8856298>

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

Modified: llvm/trunk/lib/CodeGen/DwarfEHPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/DwarfEHPrepare.cpp?rev=127640&r1=127639&r2=127640&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/DwarfEHPrepare.cpp (original)
+++ llvm/trunk/lib/CodeGen/DwarfEHPrepare.cpp Mon Mar 14 20:03:17 2011
@@ -93,7 +93,8 @@
     /// with the eh.exception call. This recursively looks past instructions
     /// which don't change the EH pointer value, like casts or PHI nodes.
     bool FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
-                             SmallPtrSet<IntrinsicInst*, 8> &SelCalls);
+                             SmallPtrSet<IntrinsicInst*, 8> &SelCalls,
+                             SmallPtrSet<PHINode*, 32> &SeenPHIs);
       
   public:
     static char ID; // Pass identification, replacement for typeid.
@@ -199,8 +200,8 @@
 /// change the EH pointer value, like casts or PHI nodes.
 bool
 DwarfEHPrepare::FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
-                                    SmallPtrSet<IntrinsicInst*, 8> &SelCalls) {
-  SmallPtrSet<PHINode*, 32> SeenPHIs;
+                                    SmallPtrSet<IntrinsicInst*, 8> &SelCalls,
+                                    SmallPtrSet<PHINode*, 32> &SeenPHIs) {
   bool Changed = false;
 
   for (Value::use_iterator
@@ -215,11 +216,11 @@
       if (Invoke->getCalledFunction() == URoR)
         URoRInvoke = true;
     } else if (CastInst *CI = dyn_cast<CastInst>(II)) {
-      Changed |= FindSelectorAndURoR(CI, URoRInvoke, SelCalls);
+      Changed |= FindSelectorAndURoR(CI, URoRInvoke, SelCalls, SeenPHIs);
     } else if (PHINode *PN = dyn_cast<PHINode>(II)) {
       if (SeenPHIs.insert(PN))
         // Don't process a PHI node more than once.
-        Changed |= FindSelectorAndURoR(PN, URoRInvoke, SelCalls);
+        Changed |= FindSelectorAndURoR(PN, URoRInvoke, SelCalls, SeenPHIs);
     }
   }
 
@@ -294,7 +295,8 @@
 
       bool URoRInvoke = false;
       SmallPtrSet<IntrinsicInst*, 8> SelCalls;
-      Changed |= FindSelectorAndURoR(EHPtr, URoRInvoke, SelCalls);
+      SmallPtrSet<PHINode*, 32> SeenPHIs;
+      Changed |= FindSelectorAndURoR(EHPtr, URoRInvoke, SelCalls, SeenPHIs);
 
       if (URoRInvoke) {
         // This EH pointer is being used by an invoke of an URoR instruction and