[llvm] [z/OS][GOFF] Implement support for writing ESD + TXT records by the GOFFObjectWriter (PR #85851)

[Ulrich Weigand via llvm-commits]

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@@ -217,34 +222,403 @@ void GOFFOstream::write_impl(const char *Ptr, size_t Size) {
   }
 }
 
+/// \brief Wrapper class for symbols used exclusively for the symbol table in a
+/// GOFF file.
+class GOFFSymbol {
+public:
+  std::string Name;
+  uint32_t EsdId;
+  uint32_t ParentEsdId;
+  const MCSymbolGOFF *MCSym;
+  GOFF::ESDSymbolType SymbolType;
+
+  GOFF::ESDNameSpaceId NameSpace = GOFF::ESD_NS_NormalName;
+  GOFF::ESDAmode Amode = GOFF::ESD_AMODE_64;
+  GOFF::ESDRmode Rmode = GOFF::ESD_RMODE_64;
+  GOFF::ESDLinkageType Linkage = GOFF::ESD_LT_XPLink;
+  GOFF::ESDExecutable Executable = GOFF::ESD_EXE_Unspecified;
+  GOFF::ESDAlignment Alignment = GOFF::ESD_ALIGN_Byte;
+  GOFF::ESDTextStyle TextStyle = GOFF::ESD_TS_ByteOriented;
+  GOFF::ESDBindingAlgorithm BindAlgorithm = GOFF::ESD_BA_Concatenate;
+  GOFF::ESDLoadingBehavior LoadBehavior = GOFF::ESD_LB_Initial;
+  GOFF::ESDBindingScope BindingScope = GOFF::ESD_BSC_Unspecified;
+  GOFF::ESDBindingStrength BindingStrength = GOFF::ESD_BST_Strong;
+  GOFF::ESDReserveQwords ReservedQwords = GOFF::ESD_RQ_0;
+
+  uint32_t SortKey = 0;
+  uint32_t SectionLength = 0;
+  uint32_t ADAEsdId = 0;
+  bool Indirect = false;
+  bool ForceRent = false;
+  bool Renamable = false;
+  bool ReadOnly = false;
+  uint32_t EASectionEsdId = 0;
+  uint32_t EASectionOffset = 0;
+
+  GOFFSymbol(StringRef Name, GOFF::ESDSymbolType Type, uint32_t EsdID,
+             uint32_t ParentEsdID)
+      : Name(Name.data(), Name.size()), EsdId(EsdID), ParentEsdId(ParentEsdID),
+        MCSym(nullptr), SymbolType(Type) {}
+  GOFFSymbol() {}
+
+  bool isForceRent() const { return ForceRent; }
+  bool isReadOnly() const { return ReadOnly; }
+  bool isRemovable() const { return false; }
+  bool isExecutable() const { return Executable == GOFF::ESD_EXE_CODE; }
+  bool isExecUnspecified() const {
+    return Executable == GOFF::ESD_EXE_Unspecified;
+  }
+  bool isWeakRef() const { return BindingStrength == GOFF::ESD_BST_Weak; }
+  bool isExternal() const {
+    return (BindingScope == GOFF::ESD_BSC_Library) ||
+           (BindingScope == GOFF::ESD_BSC_ImportExport);
+  }
+
+  void setAlignment(Align A) {
+    // The GOFF alignment is encoded as log_2 value.
+    uint8_t Log = Log2(A);
+    if (Log <= GOFF::ESD_ALIGN_4Kpage)
+      Alignment = static_cast<GOFF::ESDAlignment>(Log);
+    else
+      llvm_unreachable("Unsupported alignment");
+  }
+};
+
+/// \brief Wrapper class for sections used exclusively for representing sections
+/// of the GOFF output that have actual bytes.  This could be a ED or a PR.
+/// Relocations will always have a P-pointer to the ESDID of one of these.
+struct GOFFSection {
+  uint32_t PEsdId;
+  uint32_t REsdId;
+  uint32_t SDEsdId;
+  const MCSectionGOFF *MC;
+
+  GOFFSection(uint32_t PEsdId, uint32_t REsdId, uint32_t SDEsdId)
+      : PEsdId(PEsdId), REsdId(REsdId), SDEsdId(SDEsdId), MC(nullptr) {}
+  GOFFSection(uint32_t PEsdId, uint32_t REsdId, uint32_t SDEsdId,
+              const MCSectionGOFF *MC)
+      : PEsdId(PEsdId), REsdId(REsdId), SDEsdId(SDEsdId), MC(MC) {}
+};
+
+// An MCSymbol may map to up to two GOFF Symbols. The first is the
+// "true" underlying symbol, the second one represents any indirect
+// references to that symbol.
 class GOFFObjectWriter : public MCObjectWriter {
+  typedef DenseMap<MCSymbol const *, uint32_t> SymbolMapType;
+  typedef DenseMap<MCSection const *, GOFFSection> SectionMapType;
+
   // The target specific GOFF writer instance.
   std::unique_ptr<MCGOFFObjectTargetWriter> TargetObjectWriter;
 
+  /// Lookup table for MCSymbols to GOFFSymbols.  Needed to determine EsdIds
+  /// of symbols in Relocations.
+  SymbolMapType SymbolMap;
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uweigand wrote:

In any case, this field is write-only in this patch?

https://github.com/llvm/llvm-project/pull/85851