From 28cc1aa3a748068b6490a19fc4af2443bc7f3dbd Mon Sep 17 00:00:00 2001
From: Bill Wendling <isanbard@gmail.com>
Date: Tue, 15 Mar 2011 01:03:17 +0000
Subject: [PATCH] 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>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127640 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/DwarfEHPrepare.cpp | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/lib/CodeGen/DwarfEHPrepare.cpp b/lib/CodeGen/DwarfEHPrepare.cpp
index 0ebb5b0db70..d5a2ed977f3 100644
--- a/lib/CodeGen/DwarfEHPrepare.cpp
+++ b/lib/CodeGen/DwarfEHPrepare.cpp
@@ -93,7 +93,8 @@ namespace {
     /// 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 @@ bool DwarfEHPrepare::CleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels) {
 /// 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 @@ DwarfEHPrepare::FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
       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 DwarfEHPrepare::HandleURoRInvokes() {
 
       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