[CodeGen] [WinException] Remove a redundant explicit section switch for aarch64

[mstorsjo]

Summary

The following EmitWinEHHandlerData() implicitly switches to .xdata, just like on x86_64.

This became orphaned from the original code requiring it in 0b61d220c9b1f0 / https://reviews.llvm.org/D61095.

[efriedma]

LGTM

llvm/lib/CodeGen/AsmPrinter/WinException.cpp

void WinException::endFuncletImpl() {
 
   const MachineFunction *MF = Asm->MF;
   if (shouldEmitMoves || shouldEmitPersonality) {
     const Function &F = MF->getFunction();
     EHPersonality Per = EHPersonality::Unknown;
     if (F.hasPersonalityFn())
       Per = classifyEHPersonality(F.getPersonalityFn()->stripPointerCasts());
 
-    // On funclet exit, we emit a fake "function" end marker, so that the call
-    // to EmitWinEHHandlerData below can calculate the size of the funclet or
-    // function.
-    if (isAArch64) {
-      MCSection *XData = Asm->OutStreamer->getAssociatedXDataSection(
-          Asm->OutStreamer->getCurrentSectionOnly());
-      Asm->OutStreamer->SwitchSection(XData);
-    }
-
     // Emit an UNWIND_INFO struct describing the prologue.
     Asm->OutStreamer->EmitWinEHHandlerData();
 
     if (Per == EHPersonality::MSVC_CXX && shouldEmitPersonality &&
         !CurrentFuncletEntry->isCleanupFuncletEntry()) {
       // If this is a C++ catch funclet (or the parent function),
       // emit a reference to the LSDA for the parent function.
       StringRef FuncLinkageName = GlobalValue::dropLLVMManglingEscape(F.getName());

llvm/test/CodeGen/AArch64/win64-jumptable.ll

 ; CHECK:    b g
 ; CHECK-NEXT:  .seh_endfunclet
 ; CHECK-NEXT: .p2align  2
 ; CHECK-NEXT: .LJTI0_0:
 ; CHECK:    .word .LBB0_2-.LJTI0_0
 ; CHECK:    .word .LBB0_3-.LJTI0_0
 ; CHECK:    .word .LBB0_4-.LJTI0_0
 ; CHECK:    .word .LBB0_5-.LJTI0_0
-; CHECK:    .section  .xdata,"dr"
 ; 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]*}}

llvm/test/CodeGen/AArch64/wineh-mingw.ll

 endtryfinally:
   %tmp10 = load i32, i32* %step
   ret i32 %tmp10
 }
 ; WINEH-LABEL: foo4:
 ; WINEH: .seh_proc foo4
 ; WINEH: .seh_handler _d_eh_personality, @unwind, @except
 ; WINEH: ret
-; WINEH: .section .xdata,"dr"
-; WINEH-NEXT: .seh_handlerdata
+; WINEH:      .seh_handlerdata
 ; WINEH-NEXT: .text
 ; WINEH-NEXT: .seh_endproc
 ; WINEH: .section .xdata,"dr"
 ; WINEH-NEXT: .p2align 2
 ; WINEH-NEXT: GCC_except_table0:
 
 ; WINEH-SECTIONS: Name: .xdata
 ; WINEH-SECTIONS-NOT: Name: .gcc_except_table

llvm/test/CodeGen/AArch64/wineh1.mir

 # ASM: .seh_nop
 # ASM: .seh_save_reg x22, 56
 # ASM: .seh_save_regp x23, 32
 # ASM: .seh_save_regp x25, 16
 # ASM: .seh_save_regp_x x27, 80
 # ASM: .seh_endepilogue
 
 # ASM: .seh_endfunclet
-# ASM: .section .xdata,"dr"
 # ASM: .seh_handlerdata
 # ASM: .text
 # ASM: .seh_endproc
 
 ...
 ---
 name:            test
 alignment:       4