[clang] nolock/noalloc attributes (PR #84983)

[Doug Wyatt via cfe-commits]

================
@@ -10778,6 +10778,101 @@ def warn_imp_cast_drops_unaligned : Warning<
   "implicit cast from type %0 to type %1 drops __unaligned qualifier">,
   InGroup<DiagGroup<"unaligned-qualifier-implicit-cast">>;
 
+def warn_func_effect_allocates : Warning<
+  "'%0' function '%1' must not allocate or deallocate memory">,
+  InGroup<FunctionEffects>;
+
+def note_func_effect_allocates : Note<
+  "'%1' cannot be inferred '%0' because it allocates/deallocates memory">;
----------------
dougsonos wrote:

I decided I preferred inconsistency in DiagnosticSemaKinds.td than in the code that emits the diags:

```
        S.Diag(Diag.Loc, diag::warn_func_effect_allocates)
            << effectName << TopFuncName;
...
            S.Diag(Diag2.Loc, diag::note_func_effect_allocates)
                << effectName << CalleeName;
```

But maybe that's just a bit precious. As I was trying to word the diagnostics, there were times when they didn't always come out in consistent orders and I had bugs in passing the parameters in the right order.

https://github.com/llvm/llvm-project/pull/84983