[clang] [Driver][BoundsSafety] Add -fexperimental-bounds-safety flag (PR #70480)

[Dan Liew via cfe-commits]

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@@ -3618,6 +3618,27 @@ void CompilerInvocationBase::GenerateLangArgs(const LangOptions &Opts,
     GenerateArg(Consumer, OPT_frandomize_layout_seed_EQ, Opts.RandstructSeed);
 }
 
+static void CheckBoundsSafetyLang(InputKind IK, DiagnosticsEngine &Diags) {
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delcypher wrote:

To be clear. I think it's fine to also do the language check in the driver but I think the frontend should **also** do language check so that it is not possible to run it in an invalid configuration.

https://github.com/llvm/llvm-project/pull/70480