[WinEH] Try to make the MachineFunction CFG more accurate

This avoids emitting code for unreachable landingpad blocks that contain
calls to llvm.eh.actions and indirectbr.

It's also a first step towards unifying the SEH and WinEH lowering
codepaths. I'm keeping the old fan-in lowering of SEH around until the
preparation version works well enough that we can switch over without
breaking existing users.

llvm-svn: 235037

1 files changed, 5 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/MachineModuleInfo.cpp b/llvm/lib/CodeGen/MachineModuleInfo.cpp
index d5491213293..e8bd1f8e6d9 100644
--- a/llvm/lib/CodeGen/MachineModuleInfo.cpp
+++ b/llvm/lib/CodeGen/MachineModuleInfo.cpp
@@ -570,10 +570,13 @@ const Function *MachineModuleInfo::getPersonality() const {
 }
 
 EHPersonality MachineModuleInfo::getPersonalityType() {
-  if (PersonalityTypeCache == EHPersonality::Unknown)
-    PersonalityTypeCache = classifyEHPersonality(getPersonality());
+  if (PersonalityTypeCache == EHPersonality::Unknown) {
+    if (const Function *F = getPersonality())
+      PersonalityTypeCache = classifyEHPersonality(F);
+  }
   return PersonalityTypeCache;
 }
+
 /// getPersonalityIndex - Return unique index for current personality
 /// function. NULL/first personality function should always get zero index.
 unsigned MachineModuleInfo::getPersonalityIndex() const {