From 7111f47628df8e4377c9eff99f06d11dfc551188 Mon Sep 17 00:00:00 2001
From: David Majnemer <david.majnemer@gmail.com>
Date: Fri, 8 Jan 2016 08:03:55 +0000
Subject: [PATCH] [WinEH] Update WinEHFuncInfo if StackColoring merges allocas

Windows EH keeping track of which frame index corresponds to a catchpad
in order to inform the runtime where the catch parameter should be
initialized.  LLVM's optimizations are able to prove that the memory
used by the catch parameter can be reused with another memory
optimization, changing it's frame index.

We need to keep WinEHFuncInfo up to date with respect to this or we will
miscompile/assert.

This fixes PR26069.

llvm-svn: 257158
---
 lib/CodeGen/StackColoring.cpp         |  7 ++++
 lib/CodeGen/WinEHPrepare.cpp          |  7 ++--
 test/CodeGen/X86/catchpad-lifetime.ll | 53 +++++++++++++++++++++++++++
 3 files changed, 64 insertions(+), 3 deletions(-)
 create mode 100644 test/CodeGen/X86/catchpad-lifetime.ll

diff --git a/lib/CodeGen/StackColoring.cpp b/lib/CodeGen/StackColoring.cpp
index 3541b33a844..d0c0cf77702 100644
--- a/lib/CodeGen/StackColoring.cpp
+++ b/lib/CodeGen/StackColoring.cpp
@@ -43,6 +43,7 @@
 #include "llvm/CodeGen/PseudoSourceValue.h"
 #include "llvm/CodeGen/SlotIndexes.h"
 #include "llvm/CodeGen/StackProtector.h"
+#include "llvm/CodeGen/WinEHFuncInfo.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
@@ -570,6 +571,12 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
       }
     }
 
+  if (WinEHFuncInfo *EHInfo = MF->getWinEHFuncInfo())
+    for (WinEHTryBlockMapEntry &TBME : EHInfo->TryBlockMap)
+      for (WinEHHandlerType &H : TBME.HandlerArray)
+        if (SlotRemap.count(H.CatchObj.FrameIndex))
+          H.CatchObj.FrameIndex = SlotRemap[H.CatchObj.FrameIndex];
+
   DEBUG(dbgs()<<"Fixed "<<FixedMemOp<<" machine memory operands.\n");
   DEBUG(dbgs()<<"Fixed "<<FixedDbg<<" debug locations.\n");
   DEBUG(dbgs()<<"Fixed "<<FixedInstr<<" machine instructions.\n");
diff --git a/lib/CodeGen/WinEHPrepare.cpp b/lib/CodeGen/WinEHPrepare.cpp
index f112b1bb3b9..886c5f6070c 100644
--- a/lib/CodeGen/WinEHPrepare.cpp
+++ b/lib/CodeGen/WinEHPrepare.cpp
@@ -144,10 +144,11 @@ static void addTryBlockMapEntry(WinEHFuncInfo &FuncInfo, int TryLow,
       HT.TypeDescriptor = cast<GlobalVariable>(TypeInfo->stripPointerCasts());
     HT.Adjectives = cast<ConstantInt>(CPI->getArgOperand(1))->getZExtValue();
     HT.Handler = CPI->getParent();
-    if (isa<ConstantPointerNull>(CPI->getArgOperand(2)))
-      HT.CatchObj.Alloca = nullptr;
+    if (auto *AI =
+            dyn_cast<AllocaInst>(CPI->getArgOperand(2)->stripPointerCasts()))
+      HT.CatchObj.Alloca = AI;
     else
-      HT.CatchObj.Alloca = cast<AllocaInst>(CPI->getArgOperand(2));
+      HT.CatchObj.Alloca = nullptr;
     TBME.HandlerArray.push_back(HT);
   }
   FuncInfo.TryBlockMap.push_back(TBME);
diff --git a/test/CodeGen/X86/catchpad-lifetime.ll b/test/CodeGen/X86/catchpad-lifetime.ll
new file mode 100644
index 00000000000..38fc981d2b7
--- /dev/null
+++ b/test/CodeGen/X86/catchpad-lifetime.ll
@@ -0,0 +1,53 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
+target triple = "x86_64-pc-windows-msvc"
+
+declare void @throw()
+
+declare i32 @__CxxFrameHandler3(...)
+
+define void @test1() 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: test1:
+; 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** %alloca1]
+  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?test1@4HA"
+; CHECK: movq  $0, -16(%rbp)
+; CHECK: movq  $0, -16(%rbp)
+; CHECK: ud2
+
+unreachable:                                      ; preds = %entry
+  unreachable
+}
+
+; CHECK-LABEL: $cppxdata$test1:
+; CHECK: .long   32                      # CatchObjOffset
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.start(i64, i8* nocapture) #0
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.end(i64, i8* nocapture) #0
+
+attributes #0 = { argmemonly nounwind }