[AIX][XCOFF][BUG-Fixed] need to switch back to text section after emit a dumy eh structure

[DiggerLin]

Summary

in the patch https://reviews.llvm.org/D103651 [AIX][XCOFF] generate eh_info when vector registers are saved according to the traceback table.

when generate eh_info, it switch to other section, when it done, it need to switch back to text section again.

[jasonliu]

LGTM. Thanks.

[DiggerLin]

commit as https://reviews.llvm.org/rG9a9e6189d7973c16535233b5efcb38d13a651c56

llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp

if (!TargetLoweringObjectFileXCOFF::ShouldEmitEHBlock(MF) &&
 
     const DataLayout &DL = MMI->getModule()->getDataLayout();
     const unsigned PointerSize = DL.getPointerSize();
     // Add necessary paddings in 64 bit mode.
     OutStreamer->emitValueToAlignment(PointerSize);
 
     OutStreamer->emitIntValue(0, PointerSize);
     OutStreamer->emitIntValue(0, PointerSize);
+    OutStreamer->SwitchSection(MF->getSection());
   }
 }
 
 void PPCAIXAsmPrinter::emitTracebackTable() {
 
   // Create a symbol for the end of function.
   MCSymbol *FuncEnd = createTempSymbol(MF->getName());
   OutStreamer->emitLabel(FuncEnd);

llvm/test/CodeGen/PowerPC/aix-emit-tracebacktable-clobber-register.ll

 ; COMMON-NEXT:  .vbyte  4, L..C2-TOC[TC0]               # EHInfo Table
 
 ; COMMON:       .csect .eh_info_table[RW],2
 ; COMMON-NEXT:__ehinfo.1:
 ; COMMON-NEXT:  .vbyte  4, 0
 ; COMMON-NEXT:  .align  2
 ; COMMON-NEXT:  .vbyte  4, 0
 ; COMMON-NEXT:  .vbyte  4, 0
+; CHECK-ASM-NEXT:  .csect .text[PR],2
+; CHECK-FUNC-NEXT:  .csect .foov[PR],2
 ; COMMON-NEXT:                                         # -- End function
 ; COMMON:       .toc
 ; COMMON:      L..C2:
 ; COMMON-NEXT:  .tc __ehinfo.1[TC],__ehinfo.1