[XCOFF] Adjust .rename emission sequence

[jasonliu]

Summary

AIX assembler does not generate correct relocation when .rename appear between tc entry label and .tc directive.
So only emit .rename after .tc/.comm or other linkage is emitted.

[hubert.reinterpretcast]

@jasonliu, I would expect that this affects labels in general and not just TOC entries.

[jasonliu]

Adjust all .rename emission sequence.

[jasonliu]

In D85317#2196922, @hubert.reinterpretcast wrote:

@jasonliu, I would expect that this affects labels in general and not just TOC entries.

I'm not sure if there is a way to trigger that in our assembly code generation. But I think it's still a good idea to emit .rename after something is "defined" consistently. So I reversed all the other .rename emission sequence.

[daltenty]

LGTM, thanks!

llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp

public:
   PPCTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS)
       : PPCTargetStreamer(S), OS(OS) {}
 
   void emitTCEntry(const MCSymbol &S) override {
     if (const MCSymbolXCOFF *XSym = dyn_cast<MCSymbolXCOFF>(&S)) {
       MCSymbolXCOFF *TCSym =
           cast<MCSymbolXCOFF>(Streamer.getContext().getOrCreateSymbol(
               XSym->getSymbolTableName() + "[TC]"));
+      OS << "\t.tc " << TCSym->getName() << "," << XSym->getName() << '\n';
       if (TCSym->hasRename())
         Streamer.emitXCOFFRenameDirective(TCSym, TCSym->getSymbolTableName());
-      OS << "\t.tc " << TCSym->getName() << "," << XSym->getName() << '\n';
       return;
     }
 
     OS << "\t.tc " << S.getName() << "[TC]," << S.getName() << '\n';
   }
 
   void emitMachine(StringRef CPU) override {
     OS << "\t.machine " << CPU << '\n';

llvm/test/CodeGen/PowerPC/aix-xcoff-symbol-rename.ll

 ; ASM-NEXT:    .rename _Renamed..2222f_o_[RW],"f""o"""
 ; ASM-NEXT:    .comm _Renamed..2222f_o_[RW],4,2
 ; ASM-NEXT:    .rename ._Renamed..40f_o,".f@o"
 ; ASM-NEXT:    .extern ._Renamed..40f_o
 ; ASM-NEXT:    .rename _Renamed..40f_o[DS],"f@o"
 ; ASM-NEXT:    .extern _Renamed..40f_o[DS]
 ; ASM-NEXT:    .toc
 ; ASM-NEXT:  L..C0:
-; ASM-NEXT:    .rename _Renamed..40f_o[TC],"f@o"
 ; ASM-NEXT:    .tc _Renamed..40f_o[TC],_Renamed..40f_o[DS]
+; ASM-NEXT:    .rename _Renamed..40f_o[TC],"f@o"
 
 ; OBJ:       Disassembly of section .text:
 ; OBJ-EMPTY:
 ; OBJ-NEXT:  00000000 (idx: 6) .f$o:
 ; OBJ-NEXT:         0: 7c 08 02 a6   mflr 0
 ; OBJ-NEXT:         4: 90 01 00 08   stw 0, 8(1)
 ; OBJ-NEXT:         8: 94 21 ff c0   stwu 1, -64(1)
 ; OBJ-NEXT:         c: 4b ff ff f5   bl 0x0