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refactor to remove trans::adt and make rustc::ty::layout authoritative #36151
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Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @arielb1 (or someone else) soon. If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes. Please see the contribution instructions for more information. |
r? @eddyb |
from: &layout::Struct, | ||
size: layout::Size, | ||
variant: Option<ty::VariantDef<'tcx>>, | ||
substs: &Substs<'tcx>)->Struct<'tcx> { |
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The arguments should be indented 4 more to the right (to align with tcx: ...
) and there should be spaces around ->
.
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I've incorporated the stylistic fixes from @eddyb. For some reason, The I'm going to continue by trying to get I can't continue this until either late this evening or tomorrow. |
@@ -939,10 +939,8 @@ impl<'a, 'gcx, 'tcx> Layout { | |||
} | |||
} | |||
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if def.variants.len() == 1 { | |||
if def.variants.len() == 1 && hint == attr::ReprAny{ |
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nit: missing space after attr::ReprAny
@arielb1 |
@camlorn Look for how we check for size overflows when computing the LLVM types. |
Needs rebase |
@@ -496,6 +496,9 @@ pub struct GlobalCtxt<'tcx> { | |||
/// Cache for layouts computed from types. | |||
pub layout_cache: RefCell<FnvHashMap<Ty<'tcx>, &'tcx Layout>>, | |||
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//Used to prevent layout from recursing too deeply. |
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nit: don't put random mutable parameters on the tcx. Use a LayoutContext
.
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You can't, because the recursion doesn't go through a dedicated context. You might be able to put it in TargetDataLayout
, I guess, but that's about it.
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Space after //
. Also, ///
should be used (signifying doc comments).
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layout::Size::from_bytes(i*element_size.bytes()) | ||
}).collect::<Vec<_>>(); | ||
let contents = build_const_struct(ccx, &offsets[..], vals, true); | ||
C_struct(ccx, &contents[..], true) |
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It shouldn't be C_struct
but rather a LLVM vector type.
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It was C_struct
before, as layout::Vector
went to Repr::Univariant
. I'll see if I can figure out how to change this. But I half-suspect it'll cause all the simd tests to start failing (presumably LLVM treats vector types differently and presumably other stuff still assumes it's whatever C_struct
does).
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It shouldn't have gone through Repr
, I don't think. Ah, but it's fine because of the way we handle constants, that is, we cast a pointer to a location holding the constant, because enum variants aren't the type of the enum (and in this case, structs instead of vectors).
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Are you saying leave it or change it? I follow your explanation, but I'm not sure if you still consider it a problem worthy of being fixed.
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It's fine to leave it as it was before, however, it may actually cleaner to use a (LLVM) vector and not generate the Vec
of field types.
1 => Type::array(&Type::i8(cx), align_units), | ||
2 => Type::array(&Type::i16(cx), align_units), | ||
4 => Type::array(&Type::i32(cx), align_units), | ||
8 if machine::llalign_of_min(cx, Type::i64(cx)) == 8 => |
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This can use cx.tcx().data_layout.i64_align.abi()
- in fact, look in ty::layout
for how a similar match (for enums) was turned into a more general thing (e.g. there are architectures where i32
doesn't have an alignment of 4).
☔ The latest upstream changes (presumably #36496) made this pull request unmergeable. Please resolve the merge conflicts. |
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Don't merge this yet.
Throw your comments in for additional cleanup, and I'll incorporate them. At this point, I'm not sure what all I should try to kill still, or if there's anything else I'm not getting an unused warning about that's not being called. |
} | ||
} | ||
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fn struct_field_ptr<'blk, 'tcx>(bcx: &BlockAndBuilder<'blk, 'tcx>, | ||
st: &Struct<'tcx>, val: MaybeSizedValue, | ||
st: &layout::Struct, fields: &Vec<Ty<'tcx>>, val: MaybeSizedValue, |
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Creating vectors is expensive. This function should use the layout::Struct
to get the offset of the last field instead.
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Great job! Mostly only formatting nitpicks left.
@@ -328,6 +328,43 @@ pub enum Integer { | |||
} | |||
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impl Integer { | |||
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Extra newline.
} | ||
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pub fn to_ty<'a, 'tcx>(&self, tcx: &ty::TyCtxt<'a, 'tcx, 'tcx>, | ||
signed: bool) -> Ty<'tcx> { |
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signed
is aligned 4 spaces to the left of where it should be.
@@ -350,6 +387,18 @@ impl Integer { | |||
} | |||
} | |||
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//Find the smallest integer with the given alignment. |
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Space after //
and use ///
.
@@ -1003,6 +1061,16 @@ impl<'a, 'gcx, 'tcx> Layout { | |||
} | |||
} | |||
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if def.variants.len() == 1 && hint == attr::ReprAny{ |
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Missing space before {
. Also, this will never be reached, maybe you meant to put the hint == attr::ReprAny
in the previous if
?
//Given an enum, struct, closure, or tuple, extracts fields. | ||
//treats closures as a struct with one variant. | ||
//`empty_if_no_variants` is a switch to deal with empty enums. | ||
//if true, `variant_index` is disregarded and an empty Vec returned in this case. |
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Same: space after //
and make it ///
for doc comments.
General(ity, _) => { | ||
C_integral(ll_inttype(bcx.ccx(), ity), discr.0, true) | ||
layout::RawNullablePointer { .. } | | ||
layout::StructWrappedNullablePointer { .. } => { |
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Missing alignment on this line.
for (&val, target_offset) in | ||
vals.iter().zip( | ||
offset_after_field.iter().map(|i| i.bytes()) | ||
) { |
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You can put the second iterator in a target_offsets
variable to recover the original look.
@@ -1292,11 +1291,15 @@ impl<'tcx> EnumMemberDescriptionFactory<'tcx> { | |||
fn create_member_descriptions<'a>(&self, cx: &CrateContext<'a, 'tcx>) | |||
-> Vec<MemberDescription> { | |||
let adt = &self.enum_type.ty_adt_def().unwrap(); | |||
let substs = match self.enum_type.sty { | |||
ty::TyAdt(def, ref s) if def.adt_kind() == AdtKind::Enum => s, | |||
ref t @ _ => bug!("{} is not an enum", t) |
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Print self.enum_type
instead of the sty
.
@@ -735,7 +733,12 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> { | |||
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let base = match tr_lvalue.base { | |||
Base::Value(llval) => { | |||
let align = type_of::align_of(self.ccx, ty); | |||
//Fixme: may be wrong for &*(&simd_vec as &fmt::Debug) |
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Space after //
and FIXME
.
} | ||
} | ||
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pub fn from_primitive(ccx: &CrateContext, p: layout::Primitive)->Type { |
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Same ->
thing here.
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@bors r+ |
📌 Commit 467454b has been approved by |
refactor to remove trans::adt and make rustc::ty::layout authoritative I asked on IRC about optimizing struct layout by reordering fields from most-aligned to least-aligned and somehow ended up getting talked into doing this. The goal here is to make `layout` authoritative and to remove `adt`. The former has been accomplished by reimplementing `represent_type_uncached` and the latter is in progress. @eddyb thought I should make the PR now. My plan is to reserve the actual optimization for a second PR, as this work is useful by itself.
I asked on IRC about optimizing struct layout by reordering fields from most-aligned to least-aligned and somehow ended up getting talked into doing this. The goal here is to make
layout
authoritative and to removeadt
. The former has been accomplished by reimplementingrepresent_type_uncached
and the latter is in progress. @eddyb thought I should make the PR now.My plan is to reserve the actual optimization for a second PR, as this work is useful by itself.