[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}}
+	}
+}
+
+void nb4_inline() {}
+void nb4_not_inline(); // expected-note {{declaration cannot be inferred 'nonblocking' because it has no definition in this translation unit}}
+
+void nb4() [[clang::nonblocking]]
+{
+	nb4_inline(); // OK
+	nb4_not_inline(); // expected-warning {{'nonblocking' function must not call non-'nonblocking' function}}
+}
+
+
+struct HasVirtual {
+	virtual void unsafe(); // expected-note {{virtual method cannot be inferred 'nonblocking'}}
+};
+
+void nb5() [[clang::nonblocking]]
+{
+ 	HasVirtual hv;
+ 	hv.unsafe(); // expected-warning {{'nonblocking' function must not call non-'nonblocking' function}}
+}
+
+void nb6_unsafe(); // expected-note {{declaration cannot be inferred 'nonblocking' because it has no definition in this translation unit}}
+void nb6_transitively_unsafe()
+{
+	nb6_unsafe(); // expected-note {{function cannot be inferred 'nonblocking' because it calls non-'nonblocking' function}}
+}
+
+void nb6() [[clang::nonblocking]]
+{
+	nb6_transitively_unsafe(); // expected-warning {{'nonblocking' function must not call non-'nonblocking' function}}
+}
+
+thread_local int tl_var{ 42 };
+
+bool tl_test() [[clang::nonblocking]]
+{
+	return tl_var > 0; // expected-warning {{'nonblocking' function must not use thread-local variables}}
+}
+
+void nb7()
+{
+	// Make sure we verify blocks
+	auto blk = ^() [[clang::nonblocking]] {
+		throw 42; // expected-warning {{'nonblocking' function must not throw or catch exceptions}}
+	};
+}
+
+void nb8()
+{
+	// Make sure we verify lambdas
+	auto lambda = []() [[clang::nonblocking]] {
+		throw 42; // expected-warning {{'nonblocking' function must not throw or catch exceptions}}
+	};
+}
+
+void nb8a() [[clang::nonblocking]]
+{
+	// A blocking lambda shouldn't make the outer function unsafe.
+	auto unsafeLambda = []() {
+		throw 42;
+	};
+}
+
+void nb8b() [[clang::nonblocking]]
+{
+	// An unsafe lambda capture makes the outer function unsafe.
+	auto unsafeCapture = [foo = new int]() { // expected-warning {{'nonblocking' function must not allocate or deallocate memory}}
+		delete foo;
----------------
Sirraide wrote:

Maybe add a test for `__builtin_operator_new`/`__builtin_operator_delete` too.

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