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//@ revisions: enable-backchain disable-backchain
//@ assembly-output: emit-asm
//@ compile-flags: -O --crate-type=lib --target=s390x-unknown-linux-gnu
//@ needs-llvm-components: systemz
//@[enable-backchain] compile-flags: -Ctarget-feature=+backchain
//@[disable-backchain] compile-flags: -Ctarget-feature=-backchain
#![feature(no_core, lang_items)]
#![no_std]
#![no_core]
#[lang = "sized"]
trait Sized {}
extern "C" {
fn extern_func();
}
// CHECK-LABEL: test_backchain
#[no_mangle]
extern "C" fn test_backchain() -> i32 {
// Here we try to match if backchain register is saved to the parameter area (stored in r15/sp)
// And also if a new parameter area (160 bytes) is allocated for the upcoming function call
// enable-backchain: lgr [[REG1:.*]], %r15
// enable-backchain-NEXT: aghi %r15, -160
// enable-backchain: stg [[REG1]], 0(%r15)
// disable-backchain: aghi %r15, -160
// disable-backchain-NOT: stg %r{{.*}}, 0(%r15)
unsafe {
extern_func();
}
// enable-backchain-NEXT: brasl %r{{.*}}, extern_func@PLT
// disable-backchain: brasl %r{{.*}}, extern_func@PLT
// Make sure that the expected return value is written into %r2 (return register):
// enable-backchain-NEXT: lghi %r2, 1
// disable-backchain: lghi %r2, 0
#[cfg(target_feature = "backchain")]
{
1
}
#[cfg(not(target_feature = "backchain"))]
{
0
}
// CHECK: br %r{{.*}}
}
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