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

[Boaz Brickner via cfe-commits]

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@@ -946,6 +953,27 @@ class DiagnosticsEngine : public RefCountedBase<DiagnosticsEngine> {
     return (Level)Diags->getDiagnosticLevel(DiagID, Loc, *this);
   }
 
+  /// Diagnostic suppression mappings can be used to suppress specific
+  /// diagnostics in specific files.
+  /// Mapping file is expected to be a special case list with sections denoting
+  /// diagnostic groups and `src` entries for globs to suppress. `emit` category
+  /// can be used to disable suppression. Longest glob that matches a filepath
+  /// takes precendence. For example:
+  ///   [unused]
+  ///   src:clang/*
+  ///   src:clang/foo/*=emit
+  ///   src:clang/foo/bar/*
+  ///
+  /// Such a mappings file suppress all diagnostics produced by -Wunused in all
+  /// sources under `clang/` directory apart from `clang/foo/`. Diagnostics
+  /// under `clang/foo/bar/` will also be suppressed. Note that the FilePath is
+  /// matched against the globs as-is.
+  /// These take presumed locations into account, and can still be overriden by
+  /// clang-diagnostics pragmas.
+  void setDiagSuppressionMapping(llvm::MemoryBuffer &MB);
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bricknerb wrote:

Replace MB with what this buffer should contain.
Other places use "File", "Input", "InputBuffer", "Buffer" etc, which are all more readable than the type acronym.

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