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Store field remapping information together with the LLVM type in a new TypeLowering struct instead of an extra cache.

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This commit is contained in:
Hans Kratz 2021-08-05 19:14:55 +02:00
parent 7dbc568325
commit 4a4e9e3cf8
2 changed files with 50 additions and 26 deletions
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22
compiler/rustc_codegen_llvm/src/context.rs
View file

@ -74,15 +74,15 @@ pub struct CodegenCx<'ll, 'tcx> {
/// See <https://llvm.org/docs/LangRef.html#the-llvm-used-global-variable> for details
pub used_statics: RefCell<Vec<&'ll Value>>,
pub lltypes: RefCell<FxHashMap<(Ty<'tcx>, Option<VariantIdx>), &'ll Type>>,
/// Mapping of non-scalar types to llvm types and field remapping if needed.
pub type_lowering: RefCell<FxHashMap<(Ty<'tcx>, Option<VariantIdx>), TypeLowering<'ll>>>,
/// Mapping of scalar types to llvm types.
pub scalar_lltypes: RefCell<FxHashMap<Ty<'tcx>, &'ll Type>>,
pub pointee_infos: RefCell<FxHashMap<(Ty<'tcx>, Size), Option<PointeeInfo>>>,
pub isize_ty: &'ll Type,
/// Cache for the mapping from source index to llvm index for struct fields,
/// only present if synthetic fields are inserted for padding.
pub field_projection_cache: RefCell<FxHashMap<TyAndLayout<'tcx>, Vec<u32>>>,
pub coverage_cx: Option<coverageinfo::CrateCoverageContext<'ll, 'tcx>>,
pub dbg_cx: Option<debuginfo::CrateDebugContext<'ll, 'tcx>>,
@ -96,6 +96,15 @@ pub struct CodegenCx<'ll, 'tcx> {
local_gen_sym_counter: Cell<usize>,
}
pub struct TypeLowering<'ll> {
/// Associated LLVM type
pub lltype: &'ll Type,
/// If padding is used the slice maps fields from source order
/// to llvm order.
pub field_remapping: Option<Box<[u32]>>,
}
fn to_llvm_tls_model(tls_model: TlsModel) -> llvm::ThreadLocalMode {
match tls_model {
TlsModel::GeneralDynamic => llvm::ThreadLocalMode::GeneralDynamic,
@ -308,11 +317,10 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
const_globals: Default::default(),
statics_to_rauw: RefCell::new(Vec::new()),
used_statics: RefCell::new(Vec::new()),
lltypes: Default::default(),
type_lowering: Default::default(),
scalar_lltypes: Default::default(),
pointee_infos: Default::default(),
isize_ty,
field_projection_cache: Default::default(),
coverage_cx,
dbg_cx,
eh_personality: Cell::new(None),

54
compiler/rustc_codegen_llvm/src/type_of.rs
View file

@ -1,5 +1,6 @@
use crate::abi::FnAbi;
use crate::common::*;
use crate::context::TypeLowering;
use crate::type_::Type;
use rustc_codegen_ssa::traits::*;
use rustc_middle::bug;
@ -17,6 +18,7 @@ fn uncached_llvm_type<'a, 'tcx>(
cx: &CodegenCx<'a, 'tcx>,
layout: TyAndLayout<'tcx>,
defer: &mut Option<(&'a Type, TyAndLayout<'tcx>)>,
field_remapping: &mut Option<Box<[u32]>>,
) -> &'a Type {
match layout.abi {
Abi::Scalar(_) => bug!("handled elsewhere"),
@ -75,7 +77,8 @@ fn uncached_llvm_type<'a, 'tcx>(
FieldsShape::Array { count, .. } => cx.type_array(layout.field(cx, 0).llvm_type(cx), count),
FieldsShape::Arbitrary { .. } => match name {
None => {
let (llfields, packed) = struct_llfields(cx, layout);
let (llfields, packed, new_field_remapping) = struct_llfields(cx, layout);
*field_remapping = new_field_remapping;
cx.type_struct(&llfields, packed)
}
Some(ref name) => {
@ -90,7 +93,7 @@ fn uncached_llvm_type<'a, 'tcx>(
fn struct_llfields<'a, 'tcx>(
cx: &CodegenCx<'a, 'tcx>,
layout: TyAndLayout<'tcx>,
) -> (Vec<&'a Type>, bool) {
) -> (Vec<&'a Type>, bool, Option<Box<[u32]>>) {
debug!("struct_llfields: {:#?}", layout);
let field_count = layout.fields.count();
@ -147,11 +150,8 @@ fn struct_llfields<'a, 'tcx>(
} else {
debug!("struct_llfields: offset: {:?} stride: {:?}", offset, layout.size);
}
if padding_used {
cx.field_projection_cache.borrow_mut().insert(layout, projection);
}
(result, packed)
(result, packed, padding_used.then_some(projection.into_boxed_slice()))
}
impl<'a, 'tcx> CodegenCx<'a, 'tcx> {
@ -243,8 +243,8 @@ impl<'tcx> LayoutLlvmExt<'tcx> for TyAndLayout<'tcx> {
Variants::Single { index } => Some(index),
_ => None,
};
if let Some(&llty) = cx.lltypes.borrow().get(&(self.ty, variant_index)) {
return llty;
if let Some(ref llty) = cx.type_lowering.borrow().get(&(self.ty, variant_index)) {
return llty.lltype;
}
debug!("llvm_type({:#?})", self);
@ -256,6 +256,7 @@ impl<'tcx> LayoutLlvmExt<'tcx> for TyAndLayout<'tcx> {
let normal_ty = cx.tcx.erase_regions(self.ty);
let mut defer = None;
let mut field_remapping = None;
let llty = if self.ty != normal_ty {
let mut layout = cx.layout_of(normal_ty);
if let Some(v) = variant_index {
@ -263,17 +264,21 @@ impl<'tcx> LayoutLlvmExt<'tcx> for TyAndLayout<'tcx> {
}
layout.llvm_type(cx)
} else {
uncached_llvm_type(cx, *self, &mut defer)
uncached_llvm_type(cx, *self, &mut defer, &mut field_remapping)
};
debug!("--> mapped {:#?} to llty={:?}", self, llty);
cx.lltypes.borrow_mut().insert((self.ty, variant_index), llty);
cx.type_lowering
.borrow_mut()
.insert((self.ty, variant_index), TypeLowering { lltype: llty, field_remapping: None });
if let Some((llty, layout)) = defer {
let (llfields, packed) = struct_llfields(cx, layout);
cx.set_struct_body(llty, &llfields, packed)
let (llfields, packed, new_field_remapping) = struct_llfields(cx, layout);
cx.set_struct_body(llty, &llfields, packed);
field_remapping = new_field_remapping;
}
cx.type_lowering.borrow_mut().get_mut(&(self.ty, variant_index)).unwrap().field_remapping =
field_remapping;
llty
}
@ -363,12 +368,23 @@ impl<'tcx> LayoutLlvmExt<'tcx> for TyAndLayout<'tcx> {
FieldsShape::Array { .. } => index as u64,
// Look up llvm field index in projection cache if present. If no projection cache
// is present no padding is used and the llvm field index matches the memory index.
FieldsShape::Arbitrary { .. } => match cx.field_projection_cache.borrow().get(self) {
Some(projection) => projection[index] as u64,
None => self.fields.memory_index(index) as u64,
},
FieldsShape::Arbitrary { .. } => {
let variant_index = match self.variants {
Variants::Single { index } => Some(index),
_ => None,
};
// Look up llvm field if indexes do not match memory order due to padding. If
// `field_remapping` is `None` no padding was used and the llvm field index
// matches the memory index.
match cx.type_lowering.borrow().get(&(self.ty, variant_index)) {
Some(TypeLowering { field_remapping: Some(ref prj), .. }) => prj[index] as u64,
Some(_) => self.fields.memory_index(index) as u64,
None => {
bug!("TyAndLayout::llvm_field_index({:?}): type info not found", self)
}
}
}
}
}