[clang] [Clang] [NFC] Tablegen component diags headers (PR #134777)

[Erich Keane via cfe-commits]

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@@ -1562,6 +1563,60 @@ void clang::EmitClangDiagsCompatIDs(const llvm::RecordKeeper &Records,
     OS << "DIAG_COMPAT_IDS_END()\n";
 }
 
+/// ClangDiagsIntefaceEmitter - Emit the diagnostics interface header for
+/// a Clang component.
+void clang::EmitClangDiagsInterface(llvm::raw_ostream &OS,
+                                    const std::string &Component) {
+  if (Component.empty())
+    PrintFatalError("'-gen-clang-diags-iface' requires a component name");
+
+  std::string ComponentUpper = StringRef(Component).upper();
+  const char *Comp = Component.c_str();
+  const char *Upper = ComponentUpper.c_str();
+
+  OS << llvm::format(R"c++(
+namespace clang {
+namespace diag {
+enum {
+#define DIAG(ENUM, FLAGS, DEFAULT_MAPPING, DESC, GROUP, SFINAE, NOWERROR,      \
+             SHOWINSYSHEADER, SHOWINSYSMACRO, DEFERRABLE, CATEGORY)            \
+  ENUM,
+#define %sSTART
+#include "clang/Basic/Diagnostic%sKinds.inc"
+#undef DIAG
+  NUM_BUILTIN_%s_DIAGNOSTICS
+};
+
+#define DIAG_ENUM(ENUM_NAME)                                                   \
+  namespace ENUM_NAME {                                                        \
+  enum {
+#define DIAG_ENUM_ITEM(IDX, NAME) NAME = IDX,
+#define DIAG_ENUM_END()                                                        \
+  }                                                                            \
+  ;                                                                            \
+  }
+#include "clang/Basic/Diagnostic%sEnums.inc"
+#undef DIAG_ENUM_END
+#undef DIAG_ENUM_ITEM
+#undef DIAG_ENUM
+} // end namespace diag
+
+namespace diag_compat {
+#define DIAG_COMPAT_IDS_BEGIN() enum {
+#define DIAG_COMPAT_IDS_END()                                                  \
+  }                                                                            \
+  ;
+#define DIAG_COMPAT_ID(IDX, NAME, ...) NAME = IDX,
+#include "clang/Basic/Diagnostic%sCompatIDs.inc"
+#undef DIAG_COMPAT_ID
+#undef DIAG_COMPAT_IDS_BEGIN
+#undef DIAG_COMPAT_IDS_END
+} // end namespace diag_compat
+} // end namespace clang
+)c++",
+                     Upper, Comp, Upper, Comp, Comp);
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erichkeane wrote:

This is an unfortunate part of this interface... Does `llvm::format` not support the `std::format` positional arguments? 

https://github.com/llvm/llvm-project/pull/134777