[XCOFF][AIX] Differentiate usage of label symbol and csect symbol

Summary:
 We are using symbols to represent label and csect interchangeably before, and that could be a problem.
There are cases we would need to add storage mapping class to the symbol if that symbol is actually the name of a csect, but it's hard for us to figure out whether that symbol is a label or csect.

This patch intend to do the following:
    1. Construct a QualName (A name include the storage mapping class)
       MCSymbolXCOFF for every MCSectionXCOFF.
    2. Keep a pointer to that QualName inside of MCSectionXCOFF.
    3. Use that QualName whenever we need a symbol refers to that
       MCSectionXCOFF.
    4. Adapt the snowball effect from the above changes in
       XCOFFObjectWriter.cpp.

Reviewers: xingxue, DiggerLin, sfertile, daltenty, hubert.reinterpretcast

Reviewed By: DiggerLin, daltenty

Subscribers: wuzish, nemanjai, mgorny, hiraditya, kbarton, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69633

1 files changed, 8 insertions, 5 deletions

diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index 2d9c2cb2125..3fe401de35d 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -164,7 +164,8 @@ public:
   void EmitCOFFSectionIndex(MCSymbol const *Symbol) override;
   void EmitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset) override;
   void EmitCOFFImgRel32(MCSymbol const *Symbol, int64_t Offset) override;
-  void EmitXCOFFLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+  void EmitXCOFFLocalCommonSymbol(MCSymbol *LabelSym, uint64_t Size,
+                                  MCSymbol *CsectSym,
                                   unsigned ByteAlign) override;
   void emitELFSize(MCSymbol *Symbol, const MCExpr *Value) override;
   void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
@@ -765,16 +766,18 @@ void MCAsmStreamer::EmitCOFFImgRel32(MCSymbol const *Symbol, int64_t Offset) {
 // We need an XCOFF-specific version of this directive as the AIX syntax
 // requires a QualName argument identifying the csect name and storage mapping
 // class to appear before the alignment if we are specifying it.
-void MCAsmStreamer::EmitXCOFFLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+void MCAsmStreamer::EmitXCOFFLocalCommonSymbol(MCSymbol *LabelSym,
+                                               uint64_t Size,
+                                               MCSymbol *CsectSym,
                                                unsigned ByteAlignment) {
   assert(MAI->getLCOMMDirectiveAlignmentType() == LCOMM::Log2Alignment &&
          "We only support writing log base-2 alignment format with XCOFF.");
   assert(isPowerOf2_32(ByteAlignment) && "Alignment must be a power of 2.");
 
   OS << "\t.lcomm\t";
-  Symbol->print(OS, MAI);
-  OS << ',' << Size;
-  OS << ',' << Symbol->getName();
+  LabelSym->print(OS, MAI);
+  OS << ',' << Size << ',';
+  CsectSym->print(OS, MAI);
   OS << ',' << Log2_32(ByteAlignment);
 
   EmitEOL();