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

[Anthony Tran via cfe-commits]

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@@ -730,6 +754,18 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
       options::OPT_fno_sanitize_recover_EQ);
   RecoverableKinds &= Kinds;
 
+  // Parse any -fsanitize-trap=<...> flags the user provided, then
+  // diagnose any which do not have a matching -fsanitize=<...>
+  if (DiagnoseErrors) {
+    SanitizerMask ExplicitTrap = parseSanitizeArgs(
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anthonyhatran wrote:

I tried that, but `parseSanitizeArgs` adds in the `SanitizerMask`, `TrappingDefault`, so it enables these bits: `SanitizerKind::CFI | SanitizerKind::LocalBounds` by default. This means more warnings are emitted than what the user actually entered. I could work around this, but I thought my approach would be cleaner. Let me know if you would prefer the `parseSanitizeTrapArgs` approach though.

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