[clang] Control analysis-based diagnostics with #pragma (PR #136323)

[via cfe-commits]

================
@@ -0,0 +1,77 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Werror=unreachable-code-aggressive %s
+
+// Test that analysis-based warnings honor #pragma diagnostic controls. These
+// diagnostics are triggered at the end of a function body, so the pragma needs
+// to be enabled through to the closing curly brace in order for the diagnostic
+// to be emitted.
+
+struct [[clang::consumable(unconsumed)]] Linear {
+  [[clang::return_typestate(unconsumed)]]
+  Linear() {}
+  [[clang::callable_when(consumed)]]
+  ~Linear() {}
+};
+
+int a() {	
+  Linear l;
+  return 0; // No -Wconsumed diagnostic, analysis is not enabled.
+  return 1; // expected-error {{'return' will never be executed}}
+}
+
+#pragma clang diagnostic push
+#pragma clang diagnostic error "-Wconsumed"
+int b() {
+  Linear l;
+  return 0;  // expected-error {{invalid invocation of method '~Linear' on object 'l' while it is in the 'unconsumed' state}}
+  return 1;  // expected-error {{'return' will never be executed}}
+}
+#pragma clang diagnostic pop
+
+int c() {
+#pragma clang diagnostic push
+#pragma clang diagnostic error "-Wconsumed"
+  Linear l;
+  return 0; // No -Wconsumed diagnostic, analysis is disabled before the closing brace
+  return 1; // expected-error {{'return' will never be executed}}
+#pragma clang diagnostic pop
+}
+
+int d() {
+#pragma clang diagnostic push
+#pragma clang diagnostic error "-Wconsumed"
+#pragma clang diagnostic ignored "-Wunreachable-code-aggressive"
+  Linear l;
+  return 0; // expected-error {{invalid invocation of method '~Linear' on object 'l' while it is in the 'unconsumed' state}}
+  return 1; // Diagnostic is ignored
+}
+#pragma clang diagnostic pop
+
+int e() {
+#pragma clang diagnostic push
+#pragma clang diagnostic error "-Wconsumed"
+#pragma clang diagnostic ignored "-Wunreachable-code-aggressive"
+  Linear l;
+  return 0;
+  return 1;
+  // Both diagnostics are ignored because analysis is disabled before the
+  // closing brace.
+#pragma clang diagnostic pop
+}
+
+int f() {
+  Linear l;
+  return 0; // No -Wconsumed diagnostic, analysis is not enabled at } so it never runs to produce the diagnostic
+  return 1; // Diagnostic ignores because it was disabled at the }
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunreachable-code-aggressive"
+}
+#pragma clang diagnostic pop	
+
+int g() {
+  Linear l;
+  return 0; // No -Wconsumed diagnostic, the diagnostic generated at } is not enabled on this line.
----------------
Sirraide wrote:

Is that mentioned anywhere in the documentation, because that wasn’t obvious to me (I would have thought that *just* enabling it for the `}` would have enabled it for the entire function because of how much emphasis the documentation is placing on the `}`).

https://github.com/llvm/llvm-project/pull/136323