[SystemZ] Emit external aliases required for indirect symbol handling support

llvm/include/llvm/MC/MCSectionGOFF.h

@@ -27,6 +27,8 @@ namespace llvm {
 class MCExpr;
 
 class LLVM_ABI MCSectionGOFF final : public MCSection {
+  StringRef ExternalName; // Alternate external name.
+
   // Parent of this section. Implies that the parent is emitted first.
   MCSectionGOFF *Parent;
 
@@ -115,6 +117,12 @@ class LLVM_ABI MCSectionGOFF final : public MCSection {
   bool requiresNonZeroLength() const { return RequiresNonZeroLength; }
 
   void setName(StringRef SectionName) { Name = SectionName; }
+
+  bool hasExternalName() const { return !ExternalName.empty(); }
+  void setExternalName(StringRef Name) { ExternalName = Name; }
+  StringRef getExternalName() const {
+    return hasExternalName() ? ExternalName : getName();
+  }
 };
 } // end namespace llvm
 

llvm/include/llvm/MC/MCSymbolGOFF.h

@@ -23,6 +23,9 @@
 namespace llvm {
 
 class MCSymbolGOFF : public MCSymbol {
+
+  StringRef ExternalName; // Alternate external name.
+
   // Associated data area of the section. Needs to be emitted first.
   MCSectionGOFF *ADA = nullptr;
 
@@ -48,6 +51,12 @@ class MCSymbolGOFF : public MCSymbol {
   bool isExternal() const { return IsExternal; }
   void setExternal(bool Value) const { IsExternal = Value; }
 
+  bool hasExternalName() const { return !ExternalName.empty(); }
+  void setExternalName(StringRef Name) { ExternalName = Name; }
+  StringRef getExternalName() const {
+    return hasExternalName() ? ExternalName : getName();
+  }
+
   void setHidden(bool Value = true) {
     modifyFlags(Value ? SF_Hidden : 0, SF_Hidden);
   }

llvm/lib/MC/GOFFObjectWriter.cpp

@@ -315,22 +315,23 @@ GOFFWriter::GOFFWriter(raw_pwrite_stream &OS, MCAssembler &Asm,
 
 void GOFFWriter::defineSectionSymbols(const MCSectionGOFF &Section) {
   if (Section.isSD()) {
-    GOFFSymbol SD(Section.getName(), Section.getOrdinal(),
+    GOFFSymbol SD(Section.getExternalName(), Section.getOrdinal(),
                   Section.getSDAttributes());
     writeSymbol(SD);
   }
 
   if (Section.isED()) {
-    GOFFSymbol ED(Section.getName(), Section.getOrdinal(),
+    GOFFSymbol ED(Section.getExternalName(), Section.getOrdinal(),
                   Section.getParent()->getOrdinal(), Section.getEDAttributes());
     ED.SectionLength = Asm.getSectionAddressSize(Section);
     writeSymbol(ED);
   }
 
   if (Section.isPR()) {
     MCSectionGOFF *Parent = Section.getParent();
-    GOFFSymbol PR(Section.getName(), Section.getOrdinal(), Parent->getOrdinal(),
-                  Parent->getEDAttributes(), Section.getPRAttributes());
+    GOFFSymbol PR(Section.getExternalName(), Section.getOrdinal(),
+                  Parent->getOrdinal(), Parent->getEDAttributes(),
+                  Section.getPRAttributes());
     PR.SectionLength = Asm.getSectionAddressSize(Section);
     if (Section.requiresNonZeroLength()) {
       // We cannot have a zero-length section for data.  If we do,
@@ -347,8 +348,8 @@ void GOFFWriter::defineSectionSymbols(const MCSectionGOFF &Section) {
 
 void GOFFWriter::defineLabel(const MCSymbolGOFF &Symbol) {
   MCSectionGOFF &Section = static_cast<MCSectionGOFF &>(Symbol.getSection());
-  GOFFSymbol LD(Symbol.getName(), Symbol.getIndex(), Section.getOrdinal(),
-                Section.getEDAttributes().NameSpace,
+  GOFFSymbol LD(Symbol.getExternalName(), Symbol.getIndex(),
+                Section.getOrdinal(), Section.getEDAttributes().NameSpace,
                 GOFF::LDAttr{false, Symbol.getCodeData(),
                              Symbol.getBindingStrength(), Symbol.getLinkage(),
                              GOFF::ESD_AMODE_64, Symbol.getBindingScope()});
@@ -359,7 +360,8 @@ void GOFFWriter::defineLabel(const MCSymbolGOFF &Symbol) {
 }
 
 void GOFFWriter::defineExtern(const MCSymbolGOFF &Symbol) {
-  GOFFSymbol ER(Symbol.getName(), Symbol.getIndex(), RootSD->getOrdinal(),
+  GOFFSymbol ER(Symbol.getExternalName(), Symbol.getIndex(),
+                RootSD->getOrdinal(),
                 GOFF::ERAttr{Symbol.isIndirect(), Symbol.getCodeData(),
                              Symbol.getBindingStrength(), Symbol.getLinkage(),
                              GOFF::ESD_AMODE_64, Symbol.getBindingScope()});
@@ -695,25 +697,26 @@ void GOFFObjectWriter::recordRelocation(const MCFragment &F,
       Asm->reportError(
           Fixup.getLoc(),
           Twine("symbol ")
-              .concat(A.getName())
+              .concat(A.getExternalName())
               .concat(" must be defined for a relative immediate relocation"));
       return;
     }
     if (&A.getSection() != PSection) {
+      MCSectionGOFF &GOFFSection = static_cast<MCSectionGOFF &>(A.getSection());
       Asm->reportError(Fixup.getLoc(),
                        Twine("relative immediate relocation section mismatch: ")
-                           .concat(A.getSection().getName())
+                           .concat(GOFFSection.getExternalName())
                            .concat(" of symbol ")
-                           .concat(A.getName())
+                           .concat(A.getExternalName())
                            .concat(" <-> ")
-                           .concat(PSection->getName()));
+                           .concat(PSection->getExternalName()));
       return;
     }
     if (B) {
       Asm->reportError(
           Fixup.getLoc(),
           Twine("subtractive symbol ")
-              .concat(B->getName())
+              .concat(B->getExternalName())
               .concat(" not supported for a relative immediate relocation"));
       return;
     }
@@ -767,9 +770,11 @@ void GOFFObjectWriter::recordRelocation(const MCFragment &F,
     default:
       Con = "(unknown)";
     }
-    dbgs() << "Reloc " << N << ": " << Con << " Rptr: " << Sym->getName()
-           << " Pptr: " << PSection->getName() << " Offset: " << FixupOffset
-           << " Fixed Imm: " << FixedValue << "\n";
+    dbgs() << "Reloc " << N << ": " << Con
+           << " Rptr: " << Sym->getExternalName()
+           << " Pptr: " << PSection->getExternalName()
+           << " Offset: " << FixupOffset << " Fixed Imm: " << FixedValue
+           << "\n";
   };
   (void)DumpReloc;
 

llvm/lib/MC/MCAsmInfoGOFF.cpp

@@ -120,10 +120,15 @@ void MCAsmInfoGOFF::printSwitchToSection(const MCSection &Section,
                                          raw_ostream &OS) const {
   auto &Sec =
       const_cast<MCSectionGOFF &>(static_cast<const MCSectionGOFF &>(Section));
+  auto EmitExternalName = [&Sec, &OS]() {
+    if (Sec.hasExternalName())
+      OS << Sec.getName() << " ALIAS C'" << Sec.getExternalName() << "'\n";
+  };
   switch (Sec.SymbolType) {
   case GOFF::ESD_ST_SectionDefinition: {
     OS << Sec.getName() << " CSECT\n";
     Sec.Emitted = true;
+    EmitExternalName();
     break;
   }
   case GOFF::ESD_ST_ElementDefinition: {
@@ -134,6 +139,7 @@ void MCAsmInfoGOFF::printSwitchToSection(const MCSection &Section,
                 GOFF::ESD_EXE_Unspecified, Sec.EDAttributes.IsReadOnly, 0,
                 Sec.EDAttributes.FillByteValue, StringRef());
       Sec.Emitted = true;
+      EmitExternalName();
     } else
       OS << Sec.getName() << " CATTR\n";
     break;
@@ -151,6 +157,7 @@ void MCAsmInfoGOFF::printSwitchToSection(const MCSection &Section,
                 Sec.PRAttributes.Executable, Sec.PRAttributes.BindingScope);
       ED->Emitted = true;
       Sec.Emitted = true;
+      EmitExternalName();
     } else
       OS << ED->getName() << " CATTR PART(" << Sec.getName() << ")\n";
     break;

llvm/lib/Target/SystemZ/MCTargetDesc/SystemZHLASMAsmStreamer.cpp

@@ -258,6 +258,8 @@ void SystemZHLASMAsmStreamer::emitLabel(MCSymbol *Symbol, SMLoc Loc) {
     emitXATTR(OS, Sym->getName(), Sym->isIndirect(), Sym->getLinkage(),
               Sym->getCodeData(), Sym->getBindingScope());
     EmitEOL();
+    if (Sym->hasExternalName())
+      OS << Sym->getName() << " ALIAS C'" << Sym->getExternalName() << "'\n";
   }
 
   if (EmitLabelAndEntry) {
@@ -368,6 +370,8 @@ void SystemZHLASMAsmStreamer::finishImpl() {
     emitXATTR(OS, Sym.getName(), Sym.isIndirect(), Sym.getLinkage(),
               Sym.getCodeData(), Sym.getBindingScope());
     EmitEOL();
+    if (Sym.hasExternalName())
+      OS << Sym.getName() << " ALIAS C'" << Sym.getExternalName() << "'\n";
   }
 
   // Finish the assembly output.

llvm/lib/Target/SystemZ/MCTargetDesc/SystemZTargetStreamer.h

@@ -13,8 +13,10 @@
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCSectionGOFF.h"
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCSymbolGOFF.h"
 #include "llvm/Support/FormattedStream.h"
 #include <map>
 #include <utility>
@@ -58,6 +60,9 @@ class SystemZTargetStreamer : public MCTargetStreamer {
 
   virtual void emitMachine(StringRef CPUOrCommand) {};
 
+  virtual void emitExternalName(MCSymbol *Sym, StringRef Name) {}
+  virtual void emitExternalName(MCSection *Sec, StringRef Name) {}
+
   virtual const MCExpr *createWordDiffExpr(MCContext &Ctx, const MCSymbol *Hi,
                                            const MCSymbol *Lo) {
     return nullptr;
@@ -69,6 +74,12 @@ class SystemZTargetGOFFStreamer : public SystemZTargetStreamer {
   SystemZTargetGOFFStreamer(MCStreamer &S) : SystemZTargetStreamer(S) {}
   const MCExpr *createWordDiffExpr(MCContext &Ctx, const MCSymbol *Hi,
                                    const MCSymbol *Lo) override;
+  virtual void emitExternalName(MCSymbol *Sym, StringRef Name) override {
+    static_cast<MCSymbolGOFF *>(Sym)->setExternalName(Name);
+  }
+  virtual void emitExternalName(MCSection *Sec, StringRef Name) override {
+    static_cast<MCSectionGOFF *>(Sec)->setExternalName(Name);
+  }
 };
 
 class SystemZTargetHLASMStreamer : public SystemZTargetStreamer {
@@ -80,6 +91,12 @@ class SystemZTargetHLASMStreamer : public SystemZTargetStreamer {
   SystemZHLASMAsmStreamer &getHLASMStreamer();
   const MCExpr *createWordDiffExpr(MCContext &Ctx, const MCSymbol *Hi,
                                    const MCSymbol *Lo) override;
+  virtual void emitExternalName(MCSymbol *Sym, StringRef Name) override {
+    static_cast<MCSymbolGOFF *>(Sym)->setExternalName(Name);
+  }
+  virtual void emitExternalName(MCSection *Sec, StringRef Name) override {
+    static_cast<MCSectionGOFF *>(Sec)->setExternalName(Name);
+  }
 };
 
 class SystemZTargetELFStreamer : public SystemZTargetStreamer {