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unify size_of, align_of into one call (metrics) 

create some new (xfail'd) tests looking at tag variant alignment
This commit is contained in:
Niko Matsakis 2012-01-19 10:37:40 -08:00
parent cd1056df78
commit 85a3298229
6 changed files with 475 additions and 105 deletions
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201
src/comp/middle/shape.rs
View File

@ -238,19 +238,24 @@ fn compute_static_tag_size(ccx: @crate_ctxt, largest_variants: [uint],
ret {size: max_size, align: max_align};
}
enum tag_kind { tk_unit, tk_enum, tk_complex, }
enum tag_kind {
tk_unit, // 1 variant, no data
tk_enum, // N variants, no data
tk_newtype, // 1 variant, data
tk_complex // N variants, no data
}
fn tag_kind(ccx: @crate_ctxt, did: ast::def_id) -> tag_kind {
let variants = ty::tag_variants(ccx.tcx, did);
if vec::len(*variants) == 0u { ret tk_complex; }
for v: ty::variant_info in *variants {
if vec::len(v.args) > 0u { ret tk_complex; }
if vec::any(*variants) {|v| vec::len(v.args) > 0u} {
if vec::len(*variants) == 1u { tk_newtype }
else { tk_complex }
} else {
if vec::len(*variants) <= 1u { tk_unit }
else { tk_enum }
}
if vec::len(*variants) == 1u { ret tk_unit; }
ret tk_enum;
}
// Returns the code corresponding to the pointer size on this architecture.
fn s_int(tcx: ty_ctxt) -> u8 {
ret alt tcx.sess.targ_cfg.arch {
@ -351,7 +356,7 @@ fn shape_of(ccx: @crate_ctxt, t: ty::t, ty_param_map: [uint]) -> [u8] {
s += [s_variant_tag_t(ccx.tcx)];
}
tk_enum { s += [s_variant_tag_t(ccx.tcx)]; }
tk_complex {
tk_newtype | tk_complex {
s += [shape_tag];
let sub = [];
@ -607,20 +612,47 @@ fn gen_shape_tables(ccx: @crate_ctxt) {
// ______________________________________________________________________
// compute sizeof / alignof
fn size_of(cx: @block_ctxt, t: ty::t) -> result {
let ccx = bcx_ccx(cx);
type metrics = {
bcx: @block_ctxt,
sz: ValueRef,
align: ValueRef
};
type tag_metrics = {
bcx: @block_ctxt,
sz: ValueRef,
align: ValueRef,
payload_align: ValueRef
};
fn size_of(bcx: @block_ctxt, t: ty::t) -> result {
let ccx = bcx_ccx(bcx);
if check type_has_static_size(ccx, t) {
let sp = cx.sp;
rslt(cx, llsize_of(bcx_ccx(cx), trans::type_of(ccx, sp, t)))
} else { dynamic_size_of(cx, t) }
rslt(bcx, llsize_of(ccx, trans::type_of(ccx, bcx.sp, t)))
} else {
let { bcx, sz, align: _ } = dynamic_metrics(bcx, t);
rslt(bcx, sz)
}
}
fn align_of(cx: @block_ctxt, t: ty::t) -> result {
let ccx = bcx_ccx(cx);
fn align_of(bcx: @block_ctxt, t: ty::t) -> result {
let ccx = bcx_ccx(bcx);
if check type_has_static_size(ccx, t) {
let sp = cx.sp;
rslt(cx, llalign_of(bcx_ccx(cx), trans::type_of(ccx, sp, t)))
} else { dynamic_align_of(cx, t) }
rslt(bcx, llalign_of(ccx, trans::type_of(ccx, bcx.sp, t)))
} else {
let { bcx, sz: _, align } = dynamic_metrics(bcx, t);
rslt(bcx, align)
}
}
fn metrics(bcx: @block_ctxt, t: ty::t) -> metrics {
let ccx = bcx_ccx(bcx);
if check type_has_static_size(ccx, t) {
let llty = trans::type_of(ccx, bcx.sp, t);
{ bcx: bcx, sz: llsize_of(ccx, llty), align: llalign_of(ccx, llty) }
} else {
dynamic_metrics(bcx, t)
}
}
// Returns the real size of the given type for the current target.
@ -676,8 +708,8 @@ fn static_size_of_tag(cx: @crate_ctxt, sp: span, t: ty::t)
}
}
fn dynamic_size_of(cx: @block_ctxt, t: ty::t) -> result {
fn align_elements(cx: @block_ctxt, elts: [ty::t]) -> result {
fn dynamic_metrics(cx: @block_ctxt, t: ty::t) -> metrics {
fn align_elements(cx: @block_ctxt, elts: [ty::t]) -> metrics {
//
// C padding rules:
//
@ -700,110 +732,62 @@ fn dynamic_size_of(cx: @block_ctxt, t: ty::t) -> result {
max_align = umax(bcx, max_align, elt_align.val);
}
off = align_to(bcx, off, max_align);
//off = alt mode {
// align_total. {
// align_to(bcx, off, max_align)
// }
// align_next(t) {
// let {bcx, val: align} = align_of(bcx, t);
// align_to(bcx, off, align)
// }
//};
ret rslt(bcx, off);
ret { bcx: bcx, sz: off, align: max_align };
}
alt ty::struct(bcx_tcx(cx), t) {
ty::ty_param(p, _) {
let szptr = field_of_tydesc(cx, t, false, abi::tydesc_field_size);
ret rslt(szptr.bcx, Load(szptr.bcx, szptr.val));
let ti = none::<@tydesc_info>;
let {bcx, val: tydesc} = trans::get_tydesc(cx, t, false, ti).result;
let szptr = GEPi(bcx, tydesc, [0, abi::tydesc_field_size]);
let aptr = GEPi(bcx, tydesc, [0, abi::tydesc_field_align]);
{bcx: bcx, sz: Load(bcx, szptr), align: Load(bcx, aptr)}
}
ty::ty_rec(flds) {
let tys: [ty::t] = [];
for f: ty::field in flds { tys += [f.mt.ty]; }
ret align_elements(cx, tys);
align_elements(cx, tys)
}
ty::ty_tup(elts) {
let tys = [];
for tp in elts { tys += [tp]; }
ret align_elements(cx, tys);
align_elements(cx, tys)
}
ty::ty_tag(tid, tps) {
let bcx = cx;
let ccx = bcx_ccx(bcx);
// Compute max(variant sizes).
let max_size: ValueRef = trans::alloca(bcx, ccx.int_type);
Store(bcx, C_int(ccx, 0), max_size);
let variants = ty::tag_variants(bcx_tcx(bcx), tid);
for variant: ty::variant_info in *variants {
// Perform type substitution on the raw argument types.
let raw_tys: [ty::t] = variant.args;
let tys: [ty::t] = [];
for raw_ty: ty::t in raw_tys {
let t = ty::substitute_type_params(bcx_tcx(cx), tps, raw_ty);
tys += [t];
let compute_max_variant_size = fn@(bcx: @block_ctxt) -> result {
// Compute max(variant sizes).
let bcx = bcx;
let max_size: ValueRef = C_int(ccx, 0);
let variants = ty::tag_variants(bcx_tcx(bcx), tid);
for variant: ty::variant_info in *variants {
// Perform type substitution on the raw argument types.
let tys = vec::map(variant.args) {|raw_ty|
ty::substitute_type_params(bcx_tcx(cx), tps, raw_ty)
};
let rslt = align_elements(bcx, tys);
bcx = rslt.bcx;
max_size = umax(bcx, rslt.sz, max_size);
}
let rslt = align_elements(bcx, tys);
bcx = rslt.bcx;
let this_size = rslt.val;
let old_max_size = Load(bcx, max_size);
Store(bcx, umax(bcx, this_size, old_max_size), max_size);
}
let max_size_val = Load(bcx, max_size);
let total_size =
if vec::len(*variants) != 1u {
Add(bcx, max_size_val, llsize_of(ccx, ccx.int_type))
} else { max_size_val };
ret rslt(bcx, total_size);
rslt(bcx, max_size)
};
let {bcx, val: sz} = alt tag_kind(ccx, tid) {
tk_unit | tk_enum { rslt(bcx, llsize_of(ccx, T_tag_variant(ccx))) }
tk_newtype { compute_max_variant_size(bcx) }
tk_complex {
let {bcx, val} = compute_max_variant_size(bcx);
rslt(bcx, Add(bcx, val, llsize_of(ccx, T_tag_variant(ccx))))
}
};
{ bcx: bcx, sz: sz, align: C_int(ccx, 1) }
}
}
}
fn dynamic_align_of(cx: @block_ctxt, t: ty::t) -> result {
// FIXME: Typestate constraint that shows this alt is
// exhaustive
alt ty::struct(bcx_tcx(cx), t) {
ty::ty_param(p, _) {
let aptr = field_of_tydesc(cx, t, false, abi::tydesc_field_align);
ret rslt(aptr.bcx, Load(aptr.bcx, aptr.val));
}
ty::ty_rec(flds) {
let a = C_int(bcx_ccx(cx), 1);
let bcx = cx;
for f: ty::field in flds {
let align = align_of(bcx, f.mt.ty);
bcx = align.bcx;
a = umax(bcx, a, align.val);
}
ret rslt(bcx, a);
}
ty::ty_tag(_, _) {
ret rslt(cx, C_int(bcx_ccx(cx), 1)); // FIXME: stub
}
ty::ty_tup(elts) {
let a = C_int(bcx_ccx(cx), 1);
let bcx = cx;
for e in elts {
let align = align_of(bcx, e);
bcx = align.bcx;
a = umax(bcx, a, align.val);
}
ret rslt(bcx, a);
}
}
}
// Given a type and a field index into its corresponding type descriptor,
// returns an LLVM ValueRef of that field from the tydesc, generating the
// tydesc if necessary.
fn field_of_tydesc(cx: @block_ctxt, t: ty::t, escapes: bool, field: int) ->
result {
let ti = none::<@tydesc_info>;
let tydesc = trans::get_tydesc(cx, t, escapes, ti).result;
ret rslt(tydesc.bcx,
GEPi(tydesc.bcx, tydesc.val, [0, field]));
}
// Creates a simpler, size-equivalent type. The resulting type is guaranteed
// to have (a) the same size as the type that was passed in; (b) to be non-
// recursive. This is done by replacing all boxes in a type with boxed unit
@ -832,3 +816,14 @@ fn simplify_type(ccx: @crate_ctxt, typ: ty::t) -> ty::t {
}
ret ty::fold_ty(ccx.tcx, ty::fm_general(bind simplifier(ccx, _)), typ);
}
// Given a tag type `ty`, returns the offset of the payload.
//fn tag_payload_offs(bcx: @block_ctxt, tag_id: ast::def_id, tps: [ty::t])
// -> ValueRef {
// alt tag_kind(tag_id) {
// tk_unit | tk_enum | tk_newtype { C_int(bcx_ccx(bcx), 0) }
// tk_complex {
// compute_tag_metrics(tag_id, tps)
// }
// }
//}

251
src/comp/middle/trans.rs
View File

@ -41,8 +41,6 @@ import link::{mangle_internal_name_by_type_only,
mangle_exported_name};
import metadata::{csearch, cstore};
import util::ppaux::{ty_to_str, ty_to_short_str};
import shape::{size_of, align_of, llsize_of_real, llalign_of_real,
llsize_of, llalign_of, static_size_of_tag};
import trans_common::*;
import trans_build::*;
@ -376,6 +374,63 @@ fn trans_shared_free(cx: @block_ctxt, v: ValueRef) -> @block_ctxt {
ret cx;
}
fn umax(cx: @block_ctxt, a: ValueRef, b: ValueRef) -> ValueRef {
let cond = ICmp(cx, lib::llvm::LLVMIntULT, a, b);
ret Select(cx, cond, b, a);
}
fn umin(cx: @block_ctxt, a: ValueRef, b: ValueRef) -> ValueRef {
let cond = ICmp(cx, lib::llvm::LLVMIntULT, a, b);
ret Select(cx, cond, a, b);
}
fn align_to(cx: @block_ctxt, off: ValueRef, align: ValueRef) -> ValueRef {
let mask = Sub(cx, align, C_int(bcx_ccx(cx), 1));
let bumped = Add(cx, off, mask);
ret And(cx, bumped, Not(cx, mask));
}
// Returns the real size of the given type for the current target.
fn llsize_of_real(cx: @crate_ctxt, t: TypeRef) -> uint {
ret llvm::LLVMStoreSizeOfType(cx.td.lltd, t) as uint;
}
// Returns the real alignment of the given type for the current target.
fn llalign_of_real(cx: @crate_ctxt, t: TypeRef) -> uint {
ret llvm::LLVMPreferredAlignmentOfType(cx.td.lltd, t) as uint;
}
fn llsize_of(cx: @crate_ctxt, t: TypeRef) -> ValueRef {
ret llvm::LLVMConstIntCast(lib::llvm::llvm::LLVMSizeOf(t), cx.int_type,
False);
}
fn llalign_of(cx: @crate_ctxt, t: TypeRef) -> ValueRef {
ret llvm::LLVMConstIntCast(lib::llvm::llvm::LLVMAlignOf(t), cx.int_type,
False);
}
fn size_of(cx: @block_ctxt, t: ty::t) -> result {
size_of_(cx, t)
}
fn size_of_(cx: @block_ctxt, t: ty::t) -> result {
let ccx = bcx_ccx(cx);
if check type_has_static_size(ccx, t) {
let sp = cx.sp;
rslt(cx, llsize_of(bcx_ccx(cx), type_of(ccx, sp, t)))
} else { dynamic_size_of(cx, t) }
}
fn align_of(cx: @block_ctxt, t: ty::t) -> result {
let ccx = bcx_ccx(cx);
if check type_has_static_size(ccx, t) {
let sp = cx.sp;
rslt(cx, llalign_of(bcx_ccx(cx), type_of(ccx, sp, t)))
} else { dynamic_align_of(cx, t) }
}
fn alloca(cx: @block_ctxt, t: TypeRef) -> ValueRef {
if cx.unreachable { ret llvm::LLVMGetUndef(t); }
ret Alloca(new_raw_block_ctxt(cx.fcx, cx.fcx.llstaticallocas), t);
@ -412,6 +467,187 @@ fn mk_obstack_token(ccx: @crate_ctxt, fcx: @fn_ctxt) ->
ret Call(cx, ccx.upcalls.dynastack_mark, []);
}
// Creates a simpler, size-equivalent type. The resulting type is guaranteed
// to have (a) the same size as the type that was passed in; (b) to be non-
// recursive. This is done by replacing all boxes in a type with boxed unit
// types.
fn simplify_type(ccx: @crate_ctxt, typ: ty::t) -> ty::t {
fn simplifier(ccx: @crate_ctxt, typ: ty::t) -> ty::t {
alt ty::struct(ccx.tcx, typ) {
ty::ty_box(_) | ty::ty_iface(_, _) {
ret ty::mk_imm_box(ccx.tcx, ty::mk_nil(ccx.tcx));
}
ty::ty_uniq(_) {
ret ty::mk_imm_uniq(ccx.tcx, ty::mk_nil(ccx.tcx));
}
ty::ty_fn(_) {
ret ty::mk_tup(ccx.tcx,
[ty::mk_imm_box(ccx.tcx, ty::mk_nil(ccx.tcx)),
ty::mk_imm_box(ccx.tcx, ty::mk_nil(ccx.tcx))]);
}
ty::ty_res(_, sub, tps) {
let sub1 = ty::substitute_type_params(ccx.tcx, tps, sub);
ret ty::mk_tup(ccx.tcx,
[ty::mk_int(ccx.tcx), simplify_type(ccx, sub1)]);
}
_ { ret typ; }
}
}
ret ty::fold_ty(ccx.tcx, ty::fm_general(bind simplifier(ccx, _)), typ);
}
// Computes the size of the data part of a non-dynamically-sized tag.
fn static_size_of_tag(cx: @crate_ctxt, sp: span, t: ty::t)
: type_has_static_size(cx, t) -> uint {
if cx.tag_sizes.contains_key(t) { ret cx.tag_sizes.get(t); }
alt ty::struct(cx.tcx, t) {
ty::ty_tag(tid, subtys) {
// Compute max(variant sizes).
let max_size = 0u;
let variants = ty::tag_variants(cx.tcx, tid);
for variant: ty::variant_info in *variants {
let tup_ty = simplify_type(cx, ty::mk_tup(cx.tcx, variant.args));
// Perform any type parameter substitutions.
tup_ty = ty::substitute_type_params(cx.tcx, subtys, tup_ty);
// Here we possibly do a recursive call.
// FIXME: Avoid this check. Since the parent has static
// size, any field must as well. There should be a way to
// express that with constrained types.
check (type_has_static_size(cx, tup_ty));
let this_size = llsize_of_real(cx, type_of(cx, sp, tup_ty));
if max_size < this_size { max_size = this_size; }
}
cx.tag_sizes.insert(t, max_size);
ret max_size;
}
_ {
cx.tcx.sess.span_fatal(sp, "non-tag passed to static_size_of_tag()");
}
}
}
fn dynamic_size_of(cx: @block_ctxt, t: ty::t) -> result {
fn align_elements(cx: @block_ctxt, elts: [ty::t]) -> result {
//
// C padding rules:
//
//
// - Pad after each element so that next element is aligned.
// - Pad after final structure member so that whole structure
// is aligned to max alignment of interior.
//
let off = C_int(bcx_ccx(cx), 0);
let max_align = C_int(bcx_ccx(cx), 1);
let bcx = cx;
for e: ty::t in elts {
let elt_align = align_of(bcx, e);
bcx = elt_align.bcx;
let elt_size = size_of(bcx, e);
bcx = elt_size.bcx;
let aligned_off = align_to(bcx, off, elt_align.val);
off = Add(bcx, aligned_off, elt_size.val);
max_align = umax(bcx, max_align, elt_align.val);
}
off = align_to(bcx, off, max_align);
//off = alt mode {
// align_total. {
// align_to(bcx, off, max_align)
// }
// align_next(t) {
// let {bcx, val: align} = align_of(bcx, t);
// align_to(bcx, off, align)
// }
//};
ret rslt(bcx, off);
}
alt ty::struct(bcx_tcx(cx), t) {
ty::ty_param(p, _) {
let szptr = field_of_tydesc(cx, t, false, abi::tydesc_field_size);
ret rslt(szptr.bcx, Load(szptr.bcx, szptr.val));
}
ty::ty_rec(flds) {
let tys: [ty::t] = [];
for f: ty::field in flds { tys += [f.mt.ty]; }
ret align_elements(cx, tys);
}
ty::ty_tup(elts) {
let tys = [];
for tp in elts { tys += [tp]; }
ret align_elements(cx, tys);
}
ty::ty_tag(tid, tps) {
let bcx = cx;
let ccx = bcx_ccx(bcx);
// Compute max(variant sizes).
let max_size: ValueRef = alloca(bcx, ccx.int_type);
Store(bcx, C_int(ccx, 0), max_size);
let variants = ty::tag_variants(bcx_tcx(bcx), tid);
for variant: ty::variant_info in *variants {
// Perform type substitution on the raw argument types.
let raw_tys: [ty::t] = variant.args;
let tys: [ty::t] = [];
for raw_ty: ty::t in raw_tys {
let t = ty::substitute_type_params(bcx_tcx(cx), tps, raw_ty);
tys += [t];
}
let rslt = align_elements(bcx, tys);
bcx = rslt.bcx;
let this_size = rslt.val;
let old_max_size = Load(bcx, max_size);
Store(bcx, umax(bcx, this_size, old_max_size), max_size);
}
let max_size_val = Load(bcx, max_size);
let total_size =
if vec::len(*variants) != 1u {
Add(bcx, max_size_val, llsize_of(ccx, ccx.int_type))
} else { max_size_val };
ret rslt(bcx, total_size);
}
}
}
fn dynamic_align_of(cx: @block_ctxt, t: ty::t) -> result {
// FIXME: Typestate constraint that shows this alt is
// exhaustive
alt ty::struct(bcx_tcx(cx), t) {
ty::ty_param(p, _) {
let aptr = field_of_tydesc(cx, t, false, abi::tydesc_field_align);
ret rslt(aptr.bcx, Load(aptr.bcx, aptr.val));
}
ty::ty_rec(flds) {
let a = C_int(bcx_ccx(cx), 1);
let bcx = cx;
for f: ty::field in flds {
let align = align_of(bcx, f.mt.ty);
bcx = align.bcx;
a = umax(bcx, a, align.val);
}
ret rslt(bcx, a);
}
ty::ty_tag(_, _) {
ret rslt(cx, C_int(bcx_ccx(cx), 1)); // FIXME: stub
}
ty::ty_tup(elts) {
let a = C_int(bcx_ccx(cx), 1);
let bcx = cx;
for e in elts {
let align = align_of(bcx, e);
bcx = align.bcx;
a = umax(bcx, a, align.val);
}
ret rslt(bcx, a);
}
}
}
// Given a pointer p, returns a pointer sz(p) (i.e., inc'd by sz bytes).
// The type of the returned pointer is always i8*. If you care about the
// return type, use bump_ptr().
@ -622,6 +858,17 @@ fn trans_malloc_boxed(cx: @block_ctxt, t: ty::t) ->
// Type descriptor and type glue stuff
// Given a type and a field index into its corresponding type descriptor,
// returns an LLVM ValueRef of that field from the tydesc, generating the
// tydesc if necessary.
fn field_of_tydesc(cx: @block_ctxt, t: ty::t, escapes: bool, field: int) ->
result {
let ti = none::<@tydesc_info>;
let tydesc = get_tydesc(cx, t, escapes, ti).result;
ret rslt(tydesc.bcx,
GEPi(tydesc.bcx, tydesc.val, [0, field]));
}
// Given a type containing ty params, build a vector containing a ValueRef for
// each of the ty params it uses (from the current frame) and a vector of the
// indices of the ty params present in the type. This is used solely for

24
src/test/run-pass/tag-align-dyn-u64.rs Normal file
View File

@ -0,0 +1,24 @@
// xfail-test
tag a_tag<A> {
a_tag(A);
}
type t_rec = {
c8: u8,
t: a_tag<u64>
};
fn mk_rec() -> t_rec {
ret { c8:0u8, t:a_tag(0u64) };
}
fn is_8_byte_aligned(&&u: a_tag<u64>) -> bool {
let p = ptr::addr_of(u) as uint;
ret (p & 7u) == 0u;
}
fn main() {
let x = mk_rec();
assert is_8_byte_aligned(x.t);
}

61
src/test/run-pass/tag-align-dyn-variants.rs Normal file
View File

@ -0,0 +1,61 @@
// xfail-test
tag a_tag<A,B> {
varA(A);
varB(B);
}
type t_rec<A,B> = {
chA: u8,
tA: a_tag<A,B>,
chB: u8,
tB: a_tag<A,B>
};
fn mk_rec<A:copy,B:copy>(a: A, b: B) -> t_rec<A,B> {
ret { chA:0u8, tA:varA(a), chB:1u8, tB:varB(b) };
}
fn is_aligned<A>(amnt: uint, &&u: A) -> bool {
let p = ptr::addr_of(u) as uint;
ret (p & (amnt-1u)) == 0u;
}
fn variant_data_is_aligned<A,B>(amnt: uint, &&u: a_tag<A,B>) -> bool {
alt u {
varA(a) { is_aligned(amnt, a) }
varB(b) { is_aligned(amnt, b) }
}
}
fn main() {
let x = mk_rec(22u64, 23u64);
assert is_aligned(8u, x.tA);
assert variant_data_is_aligned(8u, x.tA);
assert is_aligned(8u, x.tB);
assert variant_data_is_aligned(8u, x.tB);
let x = mk_rec(22u64, 23u32);
assert is_aligned(8u, x.tA);
assert variant_data_is_aligned(8u, x.tA);
assert is_aligned(8u, x.tB);
assert variant_data_is_aligned(4u, x.tB);
let x = mk_rec(22u32, 23u64);
assert is_aligned(8u, x.tA);
assert variant_data_is_aligned(4u, x.tA);
assert is_aligned(8u, x.tB);
assert variant_data_is_aligned(8u, x.tB);
let x = mk_rec(22u32, 23u32);
assert is_aligned(4u, x.tA);
assert variant_data_is_aligned(4u, x.tA);
assert is_aligned(4u, x.tB);
assert variant_data_is_aligned(4u, x.tB);
let x = mk_rec(22f64, 23f64);
assert is_aligned(8u, x.tA);
assert variant_data_is_aligned(8u, x.tA);
assert is_aligned(8u, x.tB);
assert variant_data_is_aligned(8u, x.tB);
}

19
src/test/run-pass/tag-align-shape.rs Normal file
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@ -0,0 +1,19 @@
// xfail-test
//
// See issue #1535
tag a_tag {
a_tag(u64);
}
type t_rec = {
c8: u8,
t: a_tag
};
fn main() {
let x = {c8: 22u8, t: a_tag(44u64)};
let y = #fmt["%?", x];
#debug["y = %s", y];
assert y == "(22, a_tag(44))";
}

24
src/test/run-pass/tag-align-u64.rs Normal file
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@ -0,0 +1,24 @@
// xfail-test
tag a_tag {
a_tag(u64);
}
type t_rec = {
c8: u8,
t: a_tag
};
fn mk_rec() -> t_rec {
ret { c8:0u8, t:a_tag(0u64) };
}
fn is_8_byte_aligned(&&u: a_tag) -> bool {
let p = ptr::addr_of(u) as u64;
ret (p & 7u64) == 0u64;
}
fn main() {
let x = mk_rec();
assert is_8_byte_aligned(x.t);
}