File: dst-offset.rs

package info (click to toggle)
rustc 1.85.0%2Bdfsg3-1
  • links: PTS, VCS
  • area: main
  • in suites: experimental, sid, trixie
  • size: 893,396 kB
  • sloc: xml: 158,127; python: 35,830; javascript: 19,497; cpp: 19,002; sh: 17,245; ansic: 13,127; asm: 4,376; makefile: 1,051; perl: 29; lisp: 29; ruby: 19; sql: 11
file content (83 lines) | stat: -rw-r--r-- 2,213 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
//! This file tests that we correctly generate GEP instructions for DST
//! field offsets.
//@ compile-flags: -C no-prepopulate-passes -Copt-level=0

#![crate_type = "lib"]
#![feature(extern_types)]

use std::ptr::addr_of;

// Hack to get the correct type for usize
// CHECK: @helper([[USIZE:i[0-9]+]] %_1)
#[no_mangle]
pub fn helper(_: usize) {}

struct Dst<T: ?Sized> {
    x: u32,
    y: u8,
    z: T,
}

// CHECK: @dst_dyn_trait_offset(ptr align {{[0-9]+}} [[DATA_PTR:%.+]], ptr align {{[0-9]+}} [[VTABLE_PTR:%.+]])
#[no_mangle]
pub fn dst_dyn_trait_offset(s: &Dst<dyn Drop>) -> &dyn Drop {
    // The alignment of dyn trait is unknown, so we compute the offset based on align from the
    // vtable.

    // CHECK: [[SIZE_PTR:%[0-9]+]] = getelementptr inbounds i8, ptr [[VTABLE_PTR]]
    // CHECK: load [[USIZE]], ptr [[SIZE_PTR]]
    // CHECK: [[ALIGN_PTR:%[0-9]+]] = getelementptr inbounds i8, ptr [[VTABLE_PTR]]
    // CHECK: load [[USIZE]], ptr [[ALIGN_PTR]]

    // CHECK: getelementptr inbounds i8, ptr [[DATA_PTR]]
    // CHECK-NEXT: insertvalue
    // CHECK-NEXT: insertvalue
    // CHECK-NEXT: ret
    &s.z
}

// CHECK-LABEL: @dst_slice_offset
#[no_mangle]
pub fn dst_slice_offset(s: &Dst<[u16]>) -> &[u16] {
    // The alignment of [u16] is known, so we generate a GEP directly.

    // CHECK: start:
    // CHECK-NEXT: getelementptr inbounds i8, {{.+}}, [[USIZE]] 6
    // CHECK-NEXT: insertvalue
    // CHECK-NEXT: insertvalue
    // CHECK-NEXT: ret
    &s.z
}

#[repr(packed)]
struct PackedDstSlice {
    x: u32,
    y: u8,
    z: [u16],
}

// CHECK-LABEL: @packed_dst_slice_offset
#[no_mangle]
pub fn packed_dst_slice_offset(s: &PackedDstSlice) -> *const [u16] {
    // The alignment of [u16] is known, so we generate a GEP directly.

    // CHECK: start:
    // CHECK-NEXT: getelementptr inbounds i8, {{.+}}, [[USIZE]] 5
    // CHECK-NEXT: insertvalue
    // CHECK-NEXT: insertvalue
    // CHECK-NEXT: ret
    addr_of!(s.z)
}

extern "C" {
    pub type Extern;
}

// CHECK-LABEL: @dst_extern
#[no_mangle]
pub fn dst_extern(s: &Dst<Extern>) -> &Extern {
    // Computing the alignment of an extern type is currently unsupported and just panics.

    // CHECK: call void @{{.+}}panic
    &s.z
}