[clang] [WIP][DO NOT MERGE][Clang][Driver] Emit warning when -fsanitize-trap=<...> is passed without associated -fsanitize=<...> (PR #147997)

[Dan Liew via cfe-commits]

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@@ -348,6 +348,30 @@ parseSanitizeSkipHotCutoffArgs(const Driver &D, const llvm::opt::ArgList &Args,
   return Cutoffs;
 }
 
+// Given a set of mismatched bits, TrapOnly (bits the user asked to trap but
+// that aren’t actually enabled), emit a warning based on -fsanitize-trap=NAME
+static void diagnoseTrapOnly(const Driver &D, SanitizerMask &TrapOnly) {
+// Double pass: one for sanitizer groupings, one for leaves (ex: undefined vs.
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delcypher wrote:

For clarity you split this comment. One for the bit where you handle group names, and one for the individual sanitizer name (and put the comment next the code where we do this).

https://github.com/llvm/llvm-project/pull/147997