[llvm-branch-commits] [llvm] [GOFF] Add writing of section symbols (PR #133799)

[Kai Nacke via llvm-branch-commits]

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@@ -169,6 +169,91 @@ enum SubsectionKind : uint8_t {
   SK_PPA1 = 2,
   SK_PPA2 = 4,
 };
+
+// The standard System/390 convention is to name the high-order (leftmost) bit
+// in a byte as bit zero. The Flags type helps to set bits in byte according
+// to this numeration order.
+class Flags {
+  uint8_t Val;
+
+  constexpr static uint8_t bits(uint8_t BitIndex, uint8_t Length, uint8_t Value,
+                                uint8_t OldValue) {
+    uint8_t Pos = 8 - BitIndex - Length;
+    uint8_t Mask = ((1 << Length) - 1) << Pos;
+    Value = Value << Pos;
+    return (OldValue & ~Mask) | Value;
+  }
+
+public:
+  constexpr Flags() : Val(0) {}
+  constexpr Flags(uint8_t BitIndex, uint8_t Length, uint8_t Value)
+      : Val(bits(BitIndex, Length, Value, 0)) {}
+
+  template <typename T>
+  constexpr void set(uint8_t BitIndex, uint8_t Length, T NewValue) {
+    Val = bits(BitIndex, Length, static_cast<uint8_t>(NewValue), Val);
+  }
+
+  template <typename T>
+  constexpr T get(uint8_t BitIndex, uint8_t Length) const {
+    return static_cast<T>((Val >> (8 - BitIndex - Length)) &
+                          ((1 << Length) - 1));
+  }
+
+  constexpr operator uint8_t() const { return Val; }
+};
+
+// Structure for the flag field of a symbol. See
+// https://www.ibm.com/docs/en/zos/3.1.0?topic=formats-external-symbol-definition-record,
+// offset 41, for the definition.
+struct SymbolFlags {
+  Flags SymFlags;
+
+#define GOFF_SYMBOL_FLAG(NAME, TYPE, BITINDEX, LENGTH)                         \
+  void set##NAME(TYPE Val) { SymFlags.set<TYPE>(BITINDEX, LENGTH, Val); }      \
+  TYPE get##NAME() const { return SymFlags.get<TYPE>(BITINDEX, LENGTH); }
+
+  GOFF_SYMBOL_FLAG(FillBytePresence, bool, 0, 1)
+  GOFF_SYMBOL_FLAG(Mangled, bool, 1, 1)
+  GOFF_SYMBOL_FLAG(Renameable, bool, 2, 1)
+  GOFF_SYMBOL_FLAG(RemovableClass, bool, 3, 1)
+  GOFF_SYMBOL_FLAG(ReservedQwords, ESDReserveQwords, 5, 3)
+
+#undef GOFF_SYMBOL_FLAG
+
+constexpr operator uint8_t() const { return static_cast<uint8_t>(SymFlags); }
----------------
redstar wrote:

Changed.

https://github.com/llvm/llvm-project/pull/133799