Fix rdar://7879828 - crash in CallGraph, a self host issue.

Arg promotion was deleting call graph nodes that still had references
from the 'indirect' CGN.  Like the inliner, it should only delete the
function if all references are gone.

llvm-svn: 101845

2 files changed, 47 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
index 8cca4c6681a..89f213e2ac3 100644
--- a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
+++ b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
@@ -105,7 +105,7 @@ bool ArgPromotion::runOnSCC(CallGraphSCC &SCC) {
     }
     Changed |= LocalChange;               // Remember that we changed something.
   } while (LocalChange);
-
+  
   return Changed;
 }
 
@@ -874,8 +874,14 @@ CallGraphNode *ArgPromotion::DoPromotion(Function *F,
   
   NF_CGN->stealCalledFunctionsFrom(CG[F]);
   
-  // Now that the old function is dead, delete it.
-  delete CG.removeFunctionFromModule(F);
+  // Now that the old function is dead, delete it.  If there is a dangling
+  // reference to the CallgraphNode, just leave the dead function around for
+  // someone else to nuke.
+  CallGraphNode *CGN = CG[F];
+  if (CGN->getNumReferences() == 0)
+    delete CG.removeFunctionFromModule(CGN);
+  else
+    F->setLinkage(Function::ExternalLinkage);
   
   return NF_CGN;
 }
diff --git a/llvm/test/Transforms/ArgumentPromotion/crash.ll b/llvm/test/Transforms/ArgumentPromotion/crash.ll
new file mode 100644
index 00000000000..e2d3d4de9ed
--- /dev/null
+++ b/llvm/test/Transforms/ArgumentPromotion/crash.ll
@@ -0,0 +1,38 @@
+; rdar://7879828
+; RUN: opt -inline -argpromotion %s
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+target triple = "x86_64-apple-darwin10.0.0"
+
+define void @foo() {
+  invoke void @foo2()
+          to label %if.end432 unwind label %for.end520 
+
+if.end432:  
+  unreachable
+
+for.end520: 
+  unreachable
+}
+
+define internal  void @foo2() ssp {
+  %call7 = call fastcc i8* @foo3(i1 (i8*)* @foo4)
+  %call58 = call fastcc i8* @foo3(i1 (i8*)* @foo5)
+  unreachable
+}
+
+define internal fastcc i8* @foo3(i1 (i8*)* %Pred) {
+entry:
+  unreachable
+}
+
+define internal i1 @foo4(i8* %O) nounwind {
+entry:
+  %call = call zeroext i1 @foo5(i8* %O) ; <i1> [#uses=0]
+  unreachable
+}
+
+define internal i1 @foo5(i8* %O) nounwind {
+entry:
+  ret i1 undef
+}
+