[llvm] [GOFF] Refactor writing GOFF records (PR #93855)

[James Henderson via llvm-commits]

================
@@ -25,25 +25,87 @@ namespace llvm {
 // to use yaml::IO, we use these structures which are closer to the source.
 namespace GOFFYAML {
 
-struct FileHeader {
-  uint32_t TargetEnvironment = 0;
-  uint32_t TargetOperatingSystem = 0;
-  uint16_t CCSID = 0;
-  StringRef CharacterSetName;
-  StringRef LanguageProductIdentifier;
-  uint32_t ArchitectureLevel = 0;
-  std::optional<uint16_t> InternalCCSID;
-  std::optional<uint8_t> TargetSoftwareEnvironment;
+LLVM_YAML_STRONG_TYPEDEF(uint8_t, GOFF_AMODE)
+LLVM_YAML_STRONG_TYPEDEF(uint8_t, GOFF_ENDFLAGS)
+
+// The GOFF format uses different kinds of logical records. The format imposes
+// some rules on those records (e.g. the module header must come first, no
+// forward references to records, etc.). However, to be able to specify invalid
+// GOFF files, we treat all records the same way.
+struct RecordBase {
+  enum RecordBaseKind {
----------------
jh7370 wrote:

I think a more modern style would be to make this `enum class` and drop the `RBK_` prefix.

https://github.com/llvm/llvm-project/pull/93855