compiletest: limitation of compile-fail error message collection

[xen0n]

Apparently the compiletest harness couldn't cope with multiple #[cfg]'d items expected to error. During fixing of the testsuite on MIPS I got very frustrated over some of the cases, such as this one:

// irrelevant parts omitted
#[cfg(any(target_arch = "mips",
          target_arch = "mips64"))]
asm!("move $0, $1" : "=r"(x) : "=r"(5));
#[cfg(any(target_arch = "x86",
          target_arch = "x86_64",
          target_arch = "arm",
          target_arch = "aarch64"))]
asm!("mov $1, $0" : "=r"(x) : "=r"(5));
//~^ ERROR operand constraint contains '='
#[cfg(any(target_arch = "mips",
          target_arch = "mips64"))]
asm!("move $0, $1" : "=r"(x) : "=r"(5));
#[cfg(any(target_arch = "x86",
          target_arch = "x86_64",
          target_arch = "arm",
          target_arch = "aarch64"))]
asm!("mov $1, $0" : "=r"(y) : "+r"(5));
//~^ ERROR operand constraint contains '+'

---- [compile-fail] compile-fail/asm-in-bad-modifier.rs stdout ----

error: /opt/store/src/rust/src/test/compile-fail/asm-in-bad-modifier.rs:23: unexpected "error": '23:40: 23:44: input operand constraint contains '=''

error: /opt/store/src/rust/src/test/compile-fail/asm-in-bad-modifier.rs:32: unexpected "error": '32:40: 32:44: input operand constraint contains '=''

error: /opt/store/src/rust/src/test/compile-fail/asm-in-bad-modifier.rs:28: expected error not found: operand constraint contains '='

error: /opt/store/src/rust/src/test/compile-fail/asm-in-bad-modifier.rs:37: expected error not found: operand constraint contains '+'

error: 2 unexpected errors found, 2 expected errors not found

If I copy and cfg the whole function, the error is even more confusing:

#[cfg(any(target_arch = "x86",
          target_arch = "x86_64",
          target_arch = "arm",
          target_arch = "aarch64"))]
pub fn main() {
    let x: isize;
    unsafe {
        asm!("mov $1, $0" : "r"(x) : "r"(5)); //~ ERROR output operand constraint lacks '='
    }
    foo(x);
}

#[cfg(any(target_arch = "mips",
          target_arch = "mips64"))]
pub fn main() {
    let x: isize;
    unsafe {
        asm!("move $0, $1" : "r"(x) : "r"(5)); //~ ERROR output operand constraint lacks '='
    }
    foo(x);
}

error: /opt/store/src/rust/src/test/compile-fail/asm-out-no-modifier.rs:24: expected error not found: output operand constraint lacks '='

error: 0 unexpected errors found, 1 expected errors not found

Apart from duplicating the whole test case file, is there any way to fix it in compiletest instead? However upon looking at the "parsing" code used I realize it's a huge undertake as the proper solution at least needs a proper AST to begin with...

[xen0n]

Clarification: I'm asking if fixing compiletest to handle that is even worth the effort. I can always duplicate the testcases for the best practice of separating arch-dependent code according to, well, arches.

[Enselic]

I'm asking if fixing compiletest to handle that is even worth the effort.

Triage: Let's interpret 7 years of silence as "it is not worth the effort" and close this issue.

[Noratrieb]

@oli-obk since you're rewriting compiletest, here's something you may or may not want to consider

[oli-obk]

I believe this would be resolved by fixing oli-obk/ui_test#73