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
|
//! Codegen vtables and vtable accesses.
//!
//! See `rustc_codegen_ssa/src/meth.rs` for reference.
use crate::constant::data_id_for_alloc_id;
use crate::prelude::*;
pub(crate) fn vtable_memflags() -> MemFlags {
let mut flags = MemFlags::trusted(); // A vtable access is always aligned and will never trap.
flags.set_readonly(); // A vtable is always read-only.
flags
}
pub(crate) fn drop_fn_of_obj(fx: &mut FunctionCx<'_, '_, '_>, vtable: Value) -> Value {
let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes() as usize;
fx.bcx.ins().load(
fx.pointer_type,
vtable_memflags(),
vtable,
(ty::COMMON_VTABLE_ENTRIES_DROPINPLACE * usize_size) as i32,
)
}
pub(crate) fn size_of_obj(fx: &mut FunctionCx<'_, '_, '_>, vtable: Value) -> Value {
let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes() as usize;
fx.bcx.ins().load(
fx.pointer_type,
vtable_memflags(),
vtable,
(ty::COMMON_VTABLE_ENTRIES_SIZE * usize_size) as i32,
)
}
pub(crate) fn min_align_of_obj(fx: &mut FunctionCx<'_, '_, '_>, vtable: Value) -> Value {
let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes() as usize;
fx.bcx.ins().load(
fx.pointer_type,
vtable_memflags(),
vtable,
(ty::COMMON_VTABLE_ENTRIES_ALIGN * usize_size) as i32,
)
}
pub(crate) fn get_ptr_and_method_ref<'tcx>(
fx: &mut FunctionCx<'_, '_, 'tcx>,
arg: CValue<'tcx>,
idx: usize,
) -> (Value, Value) {
let (ptr, vtable) = if let Abi::ScalarPair(_, _) = arg.layout().abi {
arg.load_scalar_pair(fx)
} else {
let (ptr, vtable) = arg.try_to_ptr().unwrap();
(ptr.get_addr(fx), vtable.unwrap())
};
let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes();
let func_ref = fx.bcx.ins().load(
fx.pointer_type,
vtable_memflags(),
vtable,
(idx * usize_size as usize) as i32,
);
(ptr, func_ref)
}
pub(crate) fn get_vtable<'tcx>(
fx: &mut FunctionCx<'_, '_, 'tcx>,
ty: Ty<'tcx>,
trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
) -> Value {
let alloc_id = fx.tcx.vtable_allocation((ty, trait_ref));
let data_id =
data_id_for_alloc_id(&mut fx.constants_cx, &mut *fx.module, alloc_id, Mutability::Not);
let local_data_id = fx.module.declare_data_in_func(data_id, &mut fx.bcx.func);
if fx.clif_comments.enabled() {
fx.add_comment(local_data_id, format!("vtable: {:?}", alloc_id));
}
fx.bcx.ins().global_value(fx.pointer_type, local_data_id)
}
|
