[clang] nonblocking/nonallocating attributes: 2nd pass caller/callee analysis (PR #99656)

[via cfe-commits]

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+// RUN: %clang_cc1 -fsyntax-only -fblocks -fcxx-exceptions -std=c++20 -verify %s
+// These are in a separate file because errors (e.g. incompatible attributes) currently prevent
+// the FXAnalysis pass from running at all.
+
+// This diagnostic is re-enabled and exercised in isolation later in this file.
+#pragma clang diagnostic ignored "-Wperf-constraint-implies-noexcept"
+
+// --- CONSTRAINTS ---
+
+void nb1() [[clang::nonblocking]]
+{
+	int *pInt = new int; // expected-warning {{'nonblocking' function must not allocate or deallocate memory}}
+	delete pInt; // expected-warning {{'nonblocking' function must not allocate or deallocate memory}}
+}
+
+void nb2() [[clang::nonblocking]]
+{
+	static int global; // expected-warning {{'nonblocking' function must not have static locals}}
+}
+
+void nb3() [[clang::nonblocking]]
+{
+	try {
+		throw 42; // expected-warning {{'nonblocking' function must not throw or catch exceptions}}
+	}
+	catch (...) { // expected-warning {{'nonblocking' function must not throw or catch exceptions}}
+	}
+}
+
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Sirraide wrote:

Hmm yeah, that makes sense. It’s a bit annoying that the wording is just slightly different each time, otherwise, you could use something like `.Summary` to re-use the text of another diagnostic, but I don’t think that works for parts of it, and also, at that point it does really seem like you just want a separate diagnostic.

I think the first two here are fine. We do have a few diagnostics w/ a lot of `%select` cases (e.g. `err_deduced_tst`, `err_expr_not_cce`), but yeah, I’m not sure you can reasonably combine these any further...

https://github.com/llvm/llvm-project/pull/99656