mirror of
https://github.com/rust-lang/rust.git
synced 2026-04-27 18:57:42 +03:00
Folkert de Vries
77 lines
1.9 KiB
Rust
77 lines
1.9 KiB
Rust
//@ add-minicore
|
|
//@ min-llvm-version: 22
|
|
//@ assembly-output: emit-asm
|
|
//@ needs-llvm-components: x86
|
|
//@ compile-flags: --target=x86_64-unknown-linux-gnu
|
|
//@ compile-flags: -Copt-level=3 -C llvm-args=-x86-asm-syntax=intel
|
|
|
|
#![feature(no_core, explicit_tail_calls)]
|
|
#![expect(incomplete_features)]
|
|
#![no_core]
|
|
#![crate_type = "lib"]
|
|
|
|
// Test tail calls with `PassMode::Indirect { on_stack: false, .. }` arguments.
|
|
//
|
|
// Normally an indirect argument with `on_stack: false` would be passed as a pointer to the
|
|
// caller's stack frame. For tail calls, that would be unsound, because the caller's stack
|
|
// frame is overwritten by the callee's stack frame.
|
|
//
|
|
// The solution is to write the argument into the caller's argument place (stored somewhere further
|
|
// up the stack), and forward that place.
|
|
|
|
extern crate minicore;
|
|
use minicore::*;
|
|
|
|
#[repr(C)]
|
|
struct S {
|
|
x: u64,
|
|
y: u64,
|
|
z: u64,
|
|
}
|
|
|
|
unsafe extern "C" {
|
|
safe fn force_usage(_: u64, _: u64, _: u64) -> u64;
|
|
}
|
|
|
|
// CHECK-LABEL: callee:
|
|
// CHECK-NEXT: .cfi_startproc
|
|
//
|
|
// CHECK-NEXT: mov rax, qword ptr [rdi]
|
|
// CHECK-NEXT: mov rsi, qword ptr [rdi + 8]
|
|
// CHECK-NEXT: mov rdx, qword ptr [rdi + 16]
|
|
// CHECK-NEXT: mov rdi, rax
|
|
//
|
|
// CHECK-NEXT: jmp qword ptr [rip + force_usage@GOTPCREL]
|
|
#[inline(never)]
|
|
#[unsafe(no_mangle)]
|
|
fn callee(s: S) -> u64 {
|
|
force_usage(s.x, s.y, s.z)
|
|
}
|
|
|
|
// CHECK-LABEL: caller1:
|
|
// CHECK-NEXT: .cfi_startproc
|
|
//
|
|
// Just forward the argument:
|
|
//
|
|
// CHECK-NEXT: jmp qword ptr [rip + callee@GOTPCREL]
|
|
#[unsafe(no_mangle)]
|
|
fn caller1(s: S) -> u64 {
|
|
become callee(s);
|
|
}
|
|
|
|
// CHECK-LABEL: caller2:
|
|
// CHECK-NEXT: .cfi_startproc
|
|
//
|
|
// Construct the S value directly into the argument slot:
|
|
//
|
|
// CHECK-NEXT: mov qword ptr [rdi], 1
|
|
// CHECK-NEXT: mov qword ptr [rdi + 8], 2
|
|
// CHECK-NEXT: mov qword ptr [rdi + 16], 3
|
|
//
|
|
// CHECK-NEXT: jmp qword ptr [rip + callee@GOTPCREL]
|
|
#[unsafe(no_mangle)]
|
|
fn caller2(_: S) -> u64 {
|
|
let s = S { x: 1, y: 2, z: 3 };
|
|
become callee(s);
|
|
}
|