bjoernager/rust
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Set memflags for vtable loads

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This commit is contained in:
bjorn3 2019-12-20 16:16:28 +01:00
parent 967709f31a
commit 696053e69f
1 changed files with 10 additions and 4 deletions
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14
src/vtable.rs
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@ -6,11 +6,17 @@ const DROP_FN_INDEX: usize = 0;
const SIZE_INDEX: usize = 1; const SIZE_INDEX: usize = 1;
const ALIGN_INDEX: usize = 2; const ALIGN_INDEX: usize = 2;
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 fn drop_fn_of_obj(fx: &mut FunctionCx<'_, '_, impl Backend>, vtable: Value) -> Value { pub fn drop_fn_of_obj(fx: &mut FunctionCx<'_, '_, impl Backend>, vtable: Value) -> Value {
let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes() as usize; let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes() as usize;
fx.bcx.ins().load( fx.bcx.ins().load(
pointer_ty(fx.tcx), pointer_ty(fx.tcx),
MemFlags::new(), vtable_memflags(),
vtable, vtable,
(DROP_FN_INDEX * usize_size) as i32, (DROP_FN_INDEX * usize_size) as i32,
) )
@ -20,7 +26,7 @@ pub fn size_of_obj(fx: &mut FunctionCx<'_, '_, impl Backend>, vtable: Value) ->
let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes() as usize; let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes() as usize;
fx.bcx.ins().load( fx.bcx.ins().load(
pointer_ty(fx.tcx), pointer_ty(fx.tcx),
MemFlags::new(), vtable_memflags(),
vtable, vtable,
(SIZE_INDEX * usize_size) as i32, (SIZE_INDEX * usize_size) as i32,
) )
@ -30,7 +36,7 @@ pub fn min_align_of_obj(fx: &mut FunctionCx<'_, '_, impl Backend>, vtable: Value
let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes() as usize; let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes() as usize;
fx.bcx.ins().load( fx.bcx.ins().load(
pointer_ty(fx.tcx), pointer_ty(fx.tcx),
MemFlags::new(), vtable_memflags(),
vtable, vtable,
(ALIGN_INDEX * usize_size) as i32, (ALIGN_INDEX * usize_size) as i32,
) )
@ -45,7 +51,7 @@ pub fn get_ptr_and_method_ref<'tcx>(
let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes(); let usize_size = fx.layout_of(fx.tcx.types.usize).size.bytes();
let func_ref = fx.bcx.ins().load( let func_ref = fx.bcx.ins().load(
pointer_ty(fx.tcx), pointer_ty(fx.tcx),
MemFlags::new(), vtable_memflags(),
vtable, vtable,
((idx + 3) * usize_size as usize) as i32, ((idx + 3) * usize_size as usize) as i32,
); );