[SEH] Don't assert if the parent function lacks a personality

The EH code might have been deleted as unreachable and the personality
pruned while the filter is still present.  Currently I'm hitting this at
-O0 due to the clang bug PR24009.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241170 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/X86ISelLowering.cpp

@@ -15011,6 +15011,12 @@ static SDValue recoverFramePointer(SelectionDAG &DAG, const Function *Fn,
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   MVT PtrVT = TLI.getPointerTy();
 
+  // It's possible that the parent function no longer has a personality function
+  // if the exceptional code was optimized away, in which case we just return
+  // the incoming EBP.
+  if (!Fn->hasPersonalityFn())
+    return EntryEBP;
+
   // The RegNodeSize is 6 32-bit words for SEH and 4 for C++ EH. See
   // WinEHStatePass for the full struct definition.
   int RegNodeSize;

test/CodeGen/X86/seh-filter-no-personality.ll

@@ -0,0 +1,33 @@
+; RUN: llc -mtriple=i686-windows-msvc < %s | FileCheck %s
+
+; Mostly make sure that llvm.x86.seh.recoverfp doesn't crash if the parent
+; function lacks a personality.
+
+declare i8* @llvm.frameaddress(i32)
+declare i8* @llvm.x86.seh.recoverfp(i8*, i8*)
+
+define i32 @main() {
+entry:
+  ret i32 0
+}
+
+define internal i32 @"filt$main"() {
+entry:
+  %ebp = tail call i8* @llvm.frameaddress(i32 1)
+  %parentfp = tail call i8* @llvm.x86.seh.recoverfp(i8* bitcast (i32 ()* @main to i8*), i8* %ebp)
+  %info.addr = getelementptr inbounds i8, i8* %ebp, i32 -20
+  %0 = bitcast i8* %info.addr to i32***
+  %1 = load i32**, i32*** %0, align 4
+  %2 = load i32*, i32** %1, align 4
+  %3 = load i32, i32* %2, align 4
+  %matches = icmp eq i32 %3, u0xC0000005
+  %r = zext i1 %matches to i32
+  ret i32 %r
+}
+
+; CHECK: _main:
+; CHECK: xorl %eax, %eax
+; CHECK: retl
+
+; CHECK: _filt$main:
+; CHECK: retl