From dc706797f99edce4335866facb9a3d8b95028201 Mon Sep 17 00:00:00 2001
From: David Majnemer <david.majnemer@gmail.com>
Date: Fri, 8 Jan 2016 17:24:47 +0000
Subject: [PATCH] [WinEH] CatchHandler which don't have catch objects in
 StackColoring

StackColoring rewrites the frame indicies of operations involving
allocas if it can find that the life time of two objects do not overlap.
MSVC EH needs to be kept aware of this if happens in the event that a
catch object has moved around.  However, we represent the non-existance
of a catch object with a sentinel frame index (INT_MAX).  This sentinel
also happens to be the EmptyKey of the SlotRemap DenseMap.  Testing for
whether or not we need to translate the frame index fails in this case
because we call the count method on the DenseMap with the EmptyKey,
leading to assertions.  Instead, check if it is our sentinel value
before trying to look into the DenseMap.

This fixes PR26073.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257182 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/StackColoring.cpp         |  4 ++-
 test/CodeGen/X86/catchpad-lifetime.ll | 38 +++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/lib/CodeGen/StackColoring.cpp b/lib/CodeGen/StackColoring.cpp
index d0c0cf77702..7b520381517 100644
--- a/lib/CodeGen/StackColoring.cpp
+++ b/lib/CodeGen/StackColoring.cpp
@@ -571,10 +571,12 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
       }
     }
 
+  // Update the location of C++ catch objects for the MSVC personality routine.
   if (WinEHFuncInfo *EHInfo = MF->getWinEHFuncInfo())
     for (WinEHTryBlockMapEntry &TBME : EHInfo->TryBlockMap)
       for (WinEHHandlerType &H : TBME.HandlerArray)
-        if (SlotRemap.count(H.CatchObj.FrameIndex))
+        if (H.CatchObj.FrameIndex != INT_MAX &&
+            SlotRemap.count(H.CatchObj.FrameIndex))
           H.CatchObj.FrameIndex = SlotRemap[H.CatchObj.FrameIndex];
 
   DEBUG(dbgs()<<"Fixed "<<FixedMemOp<<" machine memory operands.\n");
diff --git a/test/CodeGen/X86/catchpad-lifetime.ll b/test/CodeGen/X86/catchpad-lifetime.ll
index 38fc981d2b7..dfd75334561 100644
--- a/test/CodeGen/X86/catchpad-lifetime.ll
+++ b/test/CodeGen/X86/catchpad-lifetime.ll
@@ -44,6 +44,44 @@ unreachable:                                      ; preds = %entry
 ; CHECK-LABEL: $cppxdata$test1:
 ; CHECK: .long   32                      # CatchObjOffset
 
+define void @test2() personality i32 (...)* @__CxxFrameHandler3 {
+entry:
+  %alloca2 = alloca i8*, align 4
+  %alloca1 = alloca i8*, align 4
+  store volatile i8* null, i8** %alloca1
+  invoke void @throw()
+          to label %unreachable unwind label %catch.dispatch
+
+; CHECK-LABEL: test2:
+; CHECK: movq  $0, -16(%rbp)
+; CHECK: callq throw
+
+catch.dispatch:                                   ; preds = %entry
+  %cs = catchswitch within none [label %catch.pad] unwind to caller
+
+catch.pad:                                        ; preds = %catch.dispatch
+  %cp = catchpad within %cs [i8* null, i32 0, i8** null]
+  store volatile i8* null, i8** %alloca1
+  %bc1 = bitcast i8** %alloca1 to i8*
+  call void @llvm.lifetime.end(i64 4, i8* nonnull %bc1)
+  %bc2 = bitcast i8** %alloca2 to i8*
+  call void @llvm.lifetime.start(i64 4, i8* %bc2)
+  store volatile i8* null, i8** %alloca1
+  unreachable
+
+; CHECK-LABEL: "?catch$2@?0?test2@4HA"
+; CHECK: movq  $0, -16(%rbp)
+; CHECK: movq  $0, -16(%rbp)
+; CHECK: ud2
+
+unreachable:                                      ; preds = %entry
+  unreachable
+}
+
+; CHECK-LABEL: $cppxdata$test2:
+; CHECK: .long   0                       # CatchObjOffset
+
+
 ; Function Attrs: argmemonly nounwind
 declare void @llvm.lifetime.start(i64, i8* nocapture) #0
 
-- 
2.34.1