[clang] nonblocking/nonallocating attributes (was: nolock/noalloc) (PR #84983)

[via cfe-commits]

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@@ -10798,6 +10798,95 @@ 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 must not allocate or deallocate memory">,
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Sirraide wrote:

I think I’ve already pointed this out before, but it’s been a while, so just as a reminder, since this is probably issued in a function anyway, I don’t think the function name really needs to be included in the diagnostic.

Also, unless this is accompanied by other diagnostics—and even then maybe actually—this diagnostic should probably indicate *why* it shouldn’t allocate memory, e.g. maybe something along the lines of ‘\<whatever expression is causing this warning> is not allowed in function declared 'nolock'/'noalloc'/\<whatever effect is causing this to be disallowed>’

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