Index: lib/CodeGen/AsmPrinter/WinException.h
===================================================================
--- lib/CodeGen/AsmPrinter/WinException.h
+++ lib/CodeGen/AsmPrinter/WinException.h
@@ -85,6 +85,7 @@
   /// only), it is relative to the frame pointer.
   int getFrameIndexOffset(int FrameIndex, const WinEHFuncInfo &FuncInfo);
 
+  void endFuncletImpl();
 public:
   //===--------------------------------------------------------------------===//
   // Main entry points.
@@ -99,6 +100,8 @@
   /// immediately after the function entry point.
   void beginFunction(const MachineFunction *MF) override;
 
+  void markFunctionEnd() override;
+
   /// Gather and emit post-function exception information.
   void endFunction(const MachineFunction *) override;
 
Index: lib/CodeGen/AsmPrinter/WinException.cpp
===================================================================
--- lib/CodeGen/AsmPrinter/WinException.cpp
+++ lib/CodeGen/AsmPrinter/WinException.cpp
@@ -109,6 +109,12 @@
   beginFunclet(MF->front(), Asm->CurrentFnSym);
 }
 
+void WinException::markFunctionEnd() {
+  if (isAArch64 && CurrentFuncletEntry &&
+      (shouldEmitMoves || shouldEmitPersonality))
+    Asm->OutStreamer->EmitWinCFIFuncletOrFuncEnd();
+}
+
 /// endFunction - Gather and emit post-function exception information.
 ///
 void WinException::endFunction(const MachineFunction *MF) {
@@ -128,7 +134,7 @@
     NonConstMF->tidyLandingPads();
   }
 
-  endFunclet();
+  endFuncletImpl();
 
   // endFunclet will emit the necessary .xdata tables for x64 SEH.
   if (Per == EHPersonality::MSVC_Win64SEH && MF->hasEHFunclets())
@@ -231,6 +237,15 @@
 }
 
 void WinException::endFunclet() {
+  if (isAArch64 && CurrentFuncletEntry &&
+      (shouldEmitMoves || shouldEmitPersonality)) {
+    Asm->OutStreamer->SwitchSection(CurrentFuncletTextSection);
+    Asm->OutStreamer->EmitWinCFIFuncletOrFuncEnd();
+  }
+  endFuncletImpl();
+}
+
+void WinException::endFuncletImpl() {
   // No funclet to process?  Great, we have nothing to do.
   if (!CurrentFuncletEntry)
     return;
@@ -246,8 +261,6 @@
     // to EmitWinEHHandlerData below can calculate the size of the funclet or
     // function.
     if (isAArch64) {
-      Asm->OutStreamer->SwitchSection(CurrentFuncletTextSection);
-      Asm->OutStreamer->EmitWinCFIFuncletOrFuncEnd();
       MCSection *XData = Asm->OutStreamer->getAssociatedXDataSection(
           Asm->OutStreamer->getCurrentSectionOnly());
       Asm->OutStreamer->SwitchSection(XData);
Index: lib/MC/MCWin64EH.cpp
===================================================================
--- lib/MC/MCWin64EH.cpp
+++ lib/MC/MCWin64EH.cpp
@@ -255,8 +255,12 @@
       MCBinaryExpr::createSub(MCSymbolRefExpr::create(LHS, Context),
                               MCSymbolRefExpr::create(RHS, Context), Context);
   MCObjectStreamer *OS = (MCObjectStreamer *)(&Streamer);
+  // It should normally be possible to calculate the length of a function
+  // at this point, but it might not be possible in the presence of certain
+  // unusual constructs, like an inline asm with an alignment directive.
   int64_t value;
-  Diff->evaluateAsAbsolute(value, OS->getAssembler());
+  if (!Diff->evaluateAsAbsolute(value, OS->getAssembler()))
+    report_fatal_error("Failed to evaluate function length in SEH unwind info");
   return value;
 }
 
@@ -498,11 +502,18 @@
   streamer.EmitLabel(Label);
   info->Symbol = Label;
 
-  uint32_t FuncLength = 0x0;
-  if (info->FuncletOrFuncEnd)
-    FuncLength = (uint32_t)GetAbsDifference(streamer, info->FuncletOrFuncEnd,
-                                            info->Begin);
-  FuncLength /= 4;
+  int64_t RawFuncLength;
+  if (!info->FuncletOrFuncEnd) {
+    // FIXME: This is very wrong; we emit SEH data which covers zero bytes
+    // of code. But otherwise test/MC/AArch64/seh.s crashes.
+    RawFuncLength = 0;
+  } else {
+    RawFuncLength = GetAbsDifference(streamer, info->FuncletOrFuncEnd,
+                                     info->Begin);
+  }
+  if (RawFuncLength > 0xFFFFF)
+    report_fatal_error("SEH unwind data splitting not yet implemented");
+  uint32_t FuncLength = (uint32_t)RawFuncLength / 4;
   uint32_t PrologCodeBytes = ARM64CountOfUnwindCodes(info->Instructions);
   uint32_t TotalCodeBytes = PrologCodeBytes;
 
Index: test/CodeGen/AArch64/win64-jumptable.ll
===================================================================
--- test/CodeGen/AArch64/win64-jumptable.ll
+++ test/CodeGen/AArch64/win64-jumptable.ll
@@ -1,4 +1,5 @@
 ; RUN: llc -o - %s -mtriple=aarch64-windows -aarch64-enable-compress-jump-tables=0 | FileCheck %s
+; RUN: llc -o - %s -mtriple=aarch64-windows -aarch64-enable-compress-jump-tables=0 -filetype=obj | llvm-readobj -unwind | FileCheck %s -check-prefix=UNWIND
 
 define void @f(i32 %x) {
 entry:
@@ -46,3 +47,6 @@
 ; CHECK:    .seh_handlerdata
 ; CHECK:    .text
 ; CHECK:    .seh_endproc
+
+; Check that we can emit an object file with correct unwind info.
+; UNWIND: FunctionLength: {{[1-9][0-9]*}}