[clang] [clang-tools-extra] [llvm] [clang] Introduce diagnostics suppression mappings (PR #112517)

[Boaz Brickner via cfe-commits]

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@@ -599,6 +600,19 @@ DiagnosticIDs::getDiagnosticSeverity(unsigned DiagID, SourceLocation Loc,
       SM.isInSystemMacro(Loc))
     return diag::Severity::Ignored;
 
+  // Apply suppression mappings if severity wasn't explicitly mapped with a
+  // clang-diagnostics pragma to ensure pragmas always take precedence over
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bricknerb wrote:

Carefully reading the comment, it's clear.
We could make it easier perhaps.

// Clang-diagnostics pragmas always take precedence over suppression mapping.

The rest of the information in the comment can be put inside the first if().

https://github.com/llvm/llvm-project/pull/112517