codegen: test frame pointer attr prefers CLI opt

This test only makes sense if you send it back in time and run it with
a now-old Rust commit, e.g. 50e0cc5
However, if you do go back that far in time, you will see it pass.

Author: workingjubilee

tests/codegen/frame-pointer-cli-control.rs

@@ -0,0 +1,35 @@
+// compile-flags: --crate-type=rlib -Copt-level=0
+// revisions: force-on aarch64-apple aarch64-apple-off
+// [force-on] compile-flags: -Cforce-frame-pointers=on
+// [aarch64-apple] needs-llvm-components: aarch64
+// [aarch64-apple] compile-flags: --target=aarch64-apple-darwin
+// [aarch64-apple-off] needs-llvm-components: aarch64
+// [aarch64-apple-off] compile-flags: --target=aarch64-apple-darwin -Cforce-frame-pointers=off
+/*
+Tests that the frame pointers can be controlled by the CLI. We find aarch64-apple-darwin useful
+because of its icy-clear policy regarding frame pointers (software SHALL be compiled with them),
+e.g. https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms says:
+
+* The frame pointer register (x29) must always address a valid frame record. Some functions —
+  such as leaf functions or tail calls — may opt not to create an entry in this list.
+  As a result, stack traces are always meaningful, even without debug information.
+*/
+#![feature(no_core, lang_items)]
+#![no_core]
+#[lang = "sized"]
+trait Sized {}
+#[lang = "copy"]
+trait Copy {}
+impl Copy for u32 {}
+
+// CHECK: define i32 @peach{{.*}}[[PEACH_ATTRS:\#[0-9]+]] {
+#[no_mangle]
+pub fn peach(x: u32) -> u32 {
+    x
+}
+
+// CHECK: attributes [[PEACH_ATTRS]] = {
+// force-on-SAME: {{.*}}"frame-pointer"="all"
+// aarch64-apple-SAME: {{.*}}"frame-pointer"="all"
+// aarch64-apple-off-NOT: {{.*}}"frame-pointer"{{.*}}
+// CHECK-SAME: }