From e23370402ca873c3115bd2cb761005b53d82feea Mon Sep 17 00:00:00 2001
From: Reid Kleckner <reid@kleckner.net>
Date: Mon, 6 Jul 2015 21:13:43 +0000
Subject: [PATCH 1/1] [WinEH] Insert the EH code load before the block
 terminator

The previous code put the load after the terminator, leading to invalid
IR and downstream crashes. This caused http://crbug.com/506446.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241509 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/WinEHPrepare.cpp             |  2 +-
 test/CodeGen/WinEH/seh-exception-code.ll | 66 ++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 test/CodeGen/WinEH/seh-exception-code.ll

diff --git a/lib/CodeGen/WinEHPrepare.cpp b/lib/CodeGen/WinEHPrepare.cpp
index dbc0d91a01e..d56a242f98c 100644
--- a/lib/CodeGen/WinEHPrepare.cpp
+++ b/lib/CodeGen/WinEHPrepare.cpp
@@ -833,7 +833,7 @@ bool WinEHPrepare::prepareExceptionHandlers(
         LoadInst *LI;
         if (auto *Phi = dyn_cast<PHINode>(I))
           LI = new LoadInst(SEHExceptionCodeSlot, "sehcode", false,
-                            Phi->getIncomingBlock(*U));
+                            Phi->getIncomingBlock(*U)->getTerminator());
         else
           LI = new LoadInst(SEHExceptionCodeSlot, "sehcode", false, I);
         U->set(LI);
diff --git a/test/CodeGen/WinEH/seh-exception-code.ll b/test/CodeGen/WinEH/seh-exception-code.ll
new file mode 100644
index 00000000000..2998e798213
--- /dev/null
+++ b/test/CodeGen/WinEH/seh-exception-code.ll
@@ -0,0 +1,66 @@
+; RUN: opt -winehprepare -S < %s | FileCheck %s
+
+; WinEHPrepare was crashing during phi demotion.
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc18.0.0"
+
+declare i32 @__C_specific_handler(...)
+
+@str = linkonce_odr unnamed_addr constant [16 x i8] c"caught it! %lx\0A\00", align 1
+
+; Function Attrs: nounwind uwtable
+declare void @maycrash()
+
+; Function Attrs: nounwind
+declare i32 @printf(i8* nocapture readonly, ...)
+
+; Function Attrs: nounwind uwtable
+define void @doit() personality i8* bitcast (i32 (...)* @__C_specific_handler to i8*) {
+entry:
+  invoke void @maycrash()
+          to label %invoke.cont unwind label %lpad
+
+invoke.cont:                                      ; preds = %entry
+  invoke void @maycrash()
+          to label %__try.cont unwind label %lpad.1
+
+lpad:                                             ; preds = %entry
+  %0 = landingpad { i8*, i32 }
+          catch i8* null
+  %1 = extractvalue { i8*, i32 } %0, 0
+  br label %__except
+
+lpad.1:                                           ; preds = %invoke.cont, %lpad
+  %2 = landingpad { i8*, i32 }
+          catch i8* null
+  %3 = extractvalue { i8*, i32 } %2, 0
+  br label %__except
+
+__except:                                         ; preds = %lpad, %lpad.1
+  %exn.slot.0 = phi i8* [ %3, %lpad.1 ], [ %1, %lpad ]
+  %4 = ptrtoint i8* %exn.slot.0 to i64
+  %5 = trunc i64 %4 to i32
+  %call = tail call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([16 x i8], [16 x i8]* @str, i64 0, i64 0), i32 %5)
+  br label %__try.cont
+
+__try.cont:                                       ; preds = %invoke.cont, %__except
+  ret void
+}
+
+; CHECK-LABEL: define void @doit()
+; CHECK: landingpad
+; CHECK: indirectbr i8* %{{[^,]*}}, [label %[[except_split1:.*]]]
+; CHECK: [[except_split1]]:
+; CHECK: call i32 @llvm.eh.exceptioncode()
+; CHECK: br label %__except
+;
+; CHECK: landingpad
+; CHECK: indirectbr i8* %{{[^,]*}}, [label %[[except_split2:.*]]]
+; CHECK: [[except_split2]]:
+; CHECK: call i32 @llvm.eh.exceptioncode()
+; CHECK: br label %__except
+;
+; CHECK: __except:
+; CHECK: phi
+; CHECK: call i32 (i8*, ...) @printf
-- 
2.34.1