[clang] [clang-tools-extra] [clang] Extend diagnose_if to accept more detailed warning information (PR #70976)

[Aaron Ballman via cfe-commits]

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@@ -269,11 +268,60 @@ CATEGORY(INSTALLAPI, REFACTORING)
   return Found;
 }
 
-DiagnosticMapping DiagnosticIDs::getDefaultMapping(unsigned DiagID) {
+//===----------------------------------------------------------------------===//
+// Custom Diagnostic information
+//===----------------------------------------------------------------------===//
+
+namespace clang {
+namespace diag {
+using CustomDiagDesc = DiagnosticIDs::CustomDiagDesc;
+class CustomDiagInfo {
+  std::vector<CustomDiagDesc> DiagInfo;
+  std::map<CustomDiagDesc, unsigned> DiagIDs;
+  std::map<diag::Group, std::vector<unsigned>> GroupToDiags;
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AaronBallman wrote:

Should these be using LLVM ADTs instead for better performance? Specifically, `SmallVector`, `[Small]DenseMap`, and `MapVector`?

https://github.com/llvm/llvm-project/pull/70976