From 1b86a3446fe136cc5e76f087f19c513971c12b83 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk@google.com>
Date: Wed, 16 Sep 2015 17:19:44 +0000
Subject: [PATCH] [WinEH] Skip state numbering when no EH pads are present

Otherwise we'd try to emit the thunk that passes the LSDA to
__CxxFrameHandler3. We don't emit the LSDA if there were no landingpads,
so we'd end up with an assembler error when trying to write the COFF
object.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247820 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/CodeGen/MachineModuleInfo.h   |  9 +++------
 lib/Target/X86/X86WinEHState.cpp           | 14 ++++++++++++++
 test/CodeGen/WinEH/wineh-statenumbering.ll |  8 ++++++++
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/include/llvm/CodeGen/MachineModuleInfo.h b/include/llvm/CodeGen/MachineModuleInfo.h
index e7574bffe3b..70a771ee368 100644
--- a/include/llvm/CodeGen/MachineModuleInfo.h
+++ b/include/llvm/CodeGen/MachineModuleInfo.h
@@ -252,6 +252,9 @@ public:
   bool callsUnwindInit() const { return CallsUnwindInit; }
   void setCallsUnwindInit(bool b) { CallsUnwindInit = b; }
 
+  bool hasEHFunclets() const { return HasEHFunclets; }
+  void setHasEHFunclets(bool V) { HasEHFunclets = V; }
+
   bool usesVAFloatArgument() const {
     return UsesVAFloatArgument;
   }
@@ -365,12 +368,6 @@ public:
     return LandingPads;
   }
 
-  bool hasEHFunclets() const {
-    return HasEHFunclets;
-  }
-
-  void setHasEHFunclets(bool V) { HasEHFunclets = true; }
-
   /// setCallSiteLandingPad - Map the landing pad's EH symbol to the call
   /// site indexes.
   void setCallSiteLandingPad(MCSymbol *Sym, ArrayRef<unsigned> Sites);
diff --git a/lib/Target/X86/X86WinEHState.cpp b/lib/Target/X86/X86WinEHState.cpp
index 38dc5db3430..d1206ec0ee0 100644
--- a/lib/Target/X86/X86WinEHState.cpp
+++ b/lib/Target/X86/X86WinEHState.cpp
@@ -167,6 +167,20 @@ bool WinEHStatePass::runOnFunction(Function &F) {
   if (!isMSVCEHPersonality(Personality))
     return false;
 
+  // Skip this function if there are no EH pads and we aren't using IR-level
+  // outlining.
+  if (WinEHParentName.empty()) {
+    bool HasPads = false;
+    for (BasicBlock &BB : F) {
+      if (BB.isEHPad()) {
+        HasPads = true;
+        break;
+      }
+    }
+    if (!HasPads)
+      return false;
+  }
+
   // Disable frame pointer elimination in this function.
   // FIXME: Do the nested handlers need to keep the parent ebp in ebp, or can we
   // use an arbitrary register?
diff --git a/test/CodeGen/WinEH/wineh-statenumbering.ll b/test/CodeGen/WinEH/wineh-statenumbering.ll
index fcbb8bd2fc3..b54843635ab 100644
--- a/test/CodeGen/WinEH/wineh-statenumbering.ll
+++ b/test/CodeGen/WinEH/wineh-statenumbering.ll
@@ -82,6 +82,14 @@ unreachable.for.entry:                            ; preds = %entry
   unreachable
 }
 
+define i32 @nopads() #0 personality i32 (...)* @__CxxFrameHandler3 {
+  ret i32 0
+}
+
+; CHECK-LABEL: define i32 @nopads()
+; CHECK-NEXT: ret i32 0
+; CHECK-NOT: __ehhandler$nopads
+
 declare void @g(i32) #0
 
 declare x86_stdcallcc void @_CxxThrowException(i8*, %eh.ThrowInfo*)
-- 
2.34.1