diff --git a/compiler/rustc_codegen_cranelift/src/vtable.rs b/compiler/rustc_codegen_cranelift/src/vtable.rs
index bbf07ffc85dbd..4d1ee47b41e17 100644
--- a/compiler/rustc_codegen_cranelift/src/vtable.rs
+++ b/compiler/rustc_codegen_cranelift/src/vtable.rs
@@ -4,10 +4,7 @@
// FIXME dedup this logic between miri, cg_llvm and cg_clif
use crate::prelude::*;
-
-const DROP_FN_INDEX: usize = 0;
-const SIZE_INDEX: usize = 1;
-const ALIGN_INDEX: usize = 2;
+use ty::VtblEntry;
fn vtable_memflags() -> MemFlags {
let mut flags = MemFlags::trusted(); // A vtable access is always aligned and will never trap.
@@ -21,7 +18,7 @@ pub(crate) fn drop_fn_of_obj(fx: &mut FunctionCx<'_, '_, '_>, vtable: Value) ->
pointer_ty(fx.tcx),
vtable_memflags(),
vtable,
- (DROP_FN_INDEX * usize_size) as i32,
+ (ty::COMMON_VTABLE_ENTRIES_DROPINPLACE * usize_size) as i32,
)
}
@@ -31,7 +28,7 @@ pub(crate) fn size_of_obj(fx: &mut FunctionCx<'_, '_, '_>, vtable: Value) -> Val
pointer_ty(fx.tcx),
vtable_memflags(),
vtable,
- (SIZE_INDEX * usize_size) as i32,
+ (ty::COMMON_VTABLE_ENTRIES_SIZE * usize_size) as i32,
)
}
@@ -41,7 +38,7 @@ pub(crate) fn min_align_of_obj(fx: &mut FunctionCx<'_, '_, '_>, vtable: Value) -
pointer_ty(fx.tcx),
vtable_memflags(),
vtable,
- (ALIGN_INDEX * usize_size) as i32,
+ (ty::COMMON_VTABLE_ENTRIES_SIZE * usize_size) as i32,
)
}
@@ -62,7 +59,7 @@ pub(crate) fn get_ptr_and_method_ref<'tcx>(
pointer_ty(fx.tcx),
vtable_memflags(),
vtable,
- ((idx + 3) * usize_size as usize) as i32,
+ (idx * usize_size as usize) as i32,
);
(ptr, func_ref)
}
@@ -98,42 +95,49 @@ fn build_vtable<'tcx>(
Instance::resolve_drop_in_place(tcx, layout.ty).polymorphize(fx.tcx),
);
- let mut components: Vec<_> = vec![Some(drop_in_place_fn), None, None];
-
- let methods_root;
- let methods = if let Some(trait_ref) = trait_ref {
- methods_root = tcx.vtable_methods(trait_ref.with_self_ty(tcx, layout.ty));
- methods_root.iter()
+ let vtable_entries = if let Some(trait_ref) = trait_ref {
+ tcx.vtable_entries(trait_ref.with_self_ty(tcx, layout.ty))
} else {
- (&[]).iter()
+ ty::COMMON_VTABLE_ENTRIES
};
- let methods = methods.cloned().map(|opt_mth| {
- opt_mth.map(|(def_id, substs)| {
- import_function(
- tcx,
- fx.module,
- Instance::resolve_for_vtable(tcx, ParamEnv::reveal_all(), def_id, substs)
- .unwrap()
- .polymorphize(fx.tcx),
- )
- })
- });
- components.extend(methods);
let mut data_ctx = DataContext::new();
let mut data = ::std::iter::repeat(0u8)
- .take(components.len() * usize_size)
+ .take(vtable_entries.len() * usize_size)
.collect::<Vec<u8>>()
.into_boxed_slice();
- write_usize(fx.tcx, &mut data, SIZE_INDEX, layout.size.bytes());
- write_usize(fx.tcx, &mut data, ALIGN_INDEX, layout.align.abi.bytes());
+ for (idx, entry) in vtable_entries.iter().enumerate() {
+ match entry {
+ VtblEntry::MetadataSize => {
+ write_usize(fx.tcx, &mut data, idx, layout.size.bytes());
+ }
+ VtblEntry::MetadataAlign => {
+ write_usize(fx.tcx, &mut data, idx, layout.align.abi.bytes());
+ }
+ VtblEntry::MetadataDropInPlace | VtblEntry::Vacant | VtblEntry::Method(_, _) => {}
+ }
+ }
data_ctx.define(data);
- for (i, component) in components.into_iter().enumerate() {
- if let Some(func_id) = component {
- let func_ref = fx.module.declare_func_in_data(func_id, &mut data_ctx);
- data_ctx.write_function_addr((i * usize_size) as u32, func_ref);
+ for (idx, entry) in vtable_entries.iter().enumerate() {
+ match entry {
+ VtblEntry::MetadataDropInPlace => {
+ let func_ref = fx.module.declare_func_in_data(drop_in_place_fn, &mut data_ctx);
+ data_ctx.write_function_addr((idx * usize_size) as u32, func_ref);
+ }
+ VtblEntry::Method(def_id, substs) => {
+ let func_id = import_function(
+ tcx,
+ fx.module,
+ Instance::resolve_for_vtable(tcx, ParamEnv::reveal_all(), *def_id, substs)
+ .unwrap()
+ .polymorphize(fx.tcx),
+ );
+ let func_ref = fx.module.declare_func_in_data(func_id, &mut data_ctx);
+ data_ctx.write_function_addr((idx * usize_size) as u32, func_ref);
+ }
+ VtblEntry::MetadataSize | VtblEntry::MetadataAlign | VtblEntry::Vacant => {}
}
}
diff --git a/compiler/rustc_codegen_ssa/src/glue.rs b/compiler/rustc_codegen_ssa/src/glue.rs
index b88de0b241141..cf217b52c86f4 100644
--- a/compiler/rustc_codegen_ssa/src/glue.rs
+++ b/compiler/rustc_codegen_ssa/src/glue.rs
@@ -23,7 +23,12 @@ pub fn size_and_align_of_dst<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
ty::Dynamic(..) => {
// load size/align from vtable
let vtable = info.unwrap();
- (meth::SIZE.get_usize(bx, vtable), meth::ALIGN.get_usize(bx, vtable))
+ (
+ meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_SIZE)
+ .get_usize(bx, vtable),
+ meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_ALIGN)
+ .get_usize(bx, vtable),
+ )
}
ty::Slice(_) | ty::Str => {
let unit = layout.field(bx, 0);
diff --git a/compiler/rustc_codegen_ssa/src/meth.rs b/compiler/rustc_codegen_ssa/src/meth.rs
index bcc19c6a44bd8..4f0de72970482 100644
--- a/compiler/rustc_codegen_ssa/src/meth.rs
+++ b/compiler/rustc_codegen_ssa/src/meth.rs
@@ -1,18 +1,14 @@
use crate::traits::*;
-use rustc_middle::ty::{self, Instance, Ty};
+use rustc_middle::ty::{self, Instance, Ty, VtblEntry, COMMON_VTABLE_ENTRIES};
use rustc_target::abi::call::FnAbi;
#[derive(Copy, Clone, Debug)]
pub struct VirtualIndex(u64);
-pub const DESTRUCTOR: VirtualIndex = VirtualIndex(0);
-pub const SIZE: VirtualIndex = VirtualIndex(1);
-pub const ALIGN: VirtualIndex = VirtualIndex(2);
-
impl<'a, 'tcx> VirtualIndex {
pub fn from_index(index: usize) -> Self {
- VirtualIndex(index as u64 + 3)
+ VirtualIndex(index as u64)
}
pub fn get_fn<Bx: BuilderMethods<'a, 'tcx>>(
@@ -77,43 +73,38 @@ pub fn get_vtable<'tcx, Cx: CodegenMethods<'tcx>>(
// Not in the cache; build it.
let nullptr = cx.const_null(cx.type_i8p_ext(cx.data_layout().instruction_address_space));
- let methods_root;
- let methods = if let Some(trait_ref) = trait_ref {
- methods_root = tcx.vtable_methods(trait_ref.with_self_ty(tcx, ty));
- methods_root.iter()
+ let vtable_entries = if let Some(trait_ref) = trait_ref {
+ tcx.vtable_entries(trait_ref.with_self_ty(tcx, ty))
} else {
- (&[]).iter()
+ COMMON_VTABLE_ENTRIES
};
- let methods = methods.cloned().map(|opt_mth| {
- opt_mth.map_or(nullptr, |(def_id, substs)| {
- cx.get_fn_addr(
+ let layout = cx.layout_of(ty);
+ // /////////////////////////////////////////////////////////////////////////////////////////////
+ // If you touch this code, be sure to also make the corresponding changes to
+ // `get_vtable` in `rust_mir/interpret/traits.rs`.
+ // /////////////////////////////////////////////////////////////////////////////////////////////
+ let components: Vec<_> = vtable_entries
+ .iter()
+ .map(|entry| match entry {
+ VtblEntry::MetadataDropInPlace => {
+ cx.get_fn_addr(Instance::resolve_drop_in_place(cx.tcx(), ty))
+ }
+ VtblEntry::MetadataSize => cx.const_usize(layout.size.bytes()),
+ VtblEntry::MetadataAlign => cx.const_usize(layout.align.abi.bytes()),
+ VtblEntry::Vacant => nullptr,
+ VtblEntry::Method(def_id, substs) => cx.get_fn_addr(
ty::Instance::resolve_for_vtable(
cx.tcx(),
ty::ParamEnv::reveal_all(),
- def_id,
+ *def_id,
substs,
)
.unwrap()
.polymorphize(cx.tcx()),
- )
+ ),
})
- });
-
- let layout = cx.layout_of(ty);
- // /////////////////////////////////////////////////////////////////////////////////////////////
- // If you touch this code, be sure to also make the corresponding changes to
- // `get_vtable` in `rust_mir/interpret/traits.rs`.
- // /////////////////////////////////////////////////////////////////////////////////////////////
- let components: Vec<_> = [
- cx.get_fn_addr(Instance::resolve_drop_in_place(cx.tcx(), ty)),
- cx.const_usize(layout.size.bytes()),
- cx.const_usize(layout.align.abi.bytes()),
- ]
- .iter()
- .cloned()
- .chain(methods)
- .collect();
+ .collect();
let vtable_const = cx.const_struct(&components, false);
let align = cx.data_layout().pointer_align.abi;
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 93200bd1f264a..2cb28d7361c33 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -332,7 +332,11 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let fn_abi = FnAbi::of_instance(&bx, virtual_drop, &[]);
let vtable = args[1];
args = &args[..1];
- (meth::DESTRUCTOR.get_fn(&mut bx, vtable, &fn_abi), fn_abi)
+ (
+ meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_DROPINPLACE)
+ .get_fn(&mut bx, vtable, &fn_abi),
+ fn_abi,
+ )
}
_ => (bx.get_fn_addr(drop_fn), FnAbi::of_instance(&bx, drop_fn, &[])),
};
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 0860520ef9dfe..a6f9a7c96f0a5 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -959,9 +959,9 @@ rustc_queries! {
desc { |tcx| "checking if item has mir available: `{}`", tcx.def_path_str(key) }
}
- query vtable_methods(key: ty::PolyTraitRef<'tcx>)
- -> &'tcx [Option<(DefId, SubstsRef<'tcx>)>] {
- desc { |tcx| "finding all methods for trait {}", tcx.def_path_str(key.def_id()) }
+ query vtable_entries(key: ty::PolyTraitRef<'tcx>)
+ -> &'tcx [ty::VtblEntry<'tcx>] {
+ desc { |tcx| "finding all vtable entries for trait {}", tcx.def_path_str(key.def_id()) }
}
query codegen_fulfill_obligation(
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 227aa8dc284e2..a2abbec74927c 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -2009,3 +2009,19 @@ impl<'tcx> fmt::Debug for SymbolName<'tcx> {
fmt::Display::fmt(&self.name, fmt)
}
}
+
+#[derive(Clone, Copy, Debug, PartialEq, HashStable)]
+pub enum VtblEntry<'tcx> {
+ MetadataDropInPlace,
+ MetadataSize,
+ MetadataAlign,
+ Vacant,
+ Method(DefId, SubstsRef<'tcx>),
+}
+
+pub const COMMON_VTABLE_ENTRIES: &[VtblEntry<'_>] =
+ &[VtblEntry::MetadataDropInPlace, VtblEntry::MetadataSize, VtblEntry::MetadataAlign];
+
+pub const COMMON_VTABLE_ENTRIES_DROPINPLACE: usize = 0;
+pub const COMMON_VTABLE_ENTRIES_SIZE: usize = 1;
+pub const COMMON_VTABLE_ENTRIES_ALIGN: usize = 2;
diff --git a/compiler/rustc_mir/src/interpret/traits.rs b/compiler/rustc_mir/src/interpret/traits.rs
index 9a59161f08f50..072c252be2f30 100644
--- a/compiler/rustc_mir/src/interpret/traits.rs
+++ b/compiler/rustc_mir/src/interpret/traits.rs
@@ -1,7 +1,10 @@
use std::convert::TryFrom;
use rustc_middle::mir::interpret::{InterpResult, Pointer, PointerArithmetic, Scalar};
-use rustc_middle::ty::{self, Instance, Ty};
+use rustc_middle::ty::{
+ self, Instance, Ty, VtblEntry, COMMON_VTABLE_ENTRIES, COMMON_VTABLE_ENTRIES_ALIGN,
+ COMMON_VTABLE_ENTRIES_DROPINPLACE, COMMON_VTABLE_ENTRIES_SIZE,
+};
use rustc_target::abi::{Align, LayoutOf, Size};
use super::util::ensure_monomorphic_enough;
@@ -35,13 +38,13 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
return Ok(vtable);
}
- let methods = if let Some(poly_trait_ref) = poly_trait_ref {
+ let vtable_entries = if let Some(poly_trait_ref) = poly_trait_ref {
let trait_ref = poly_trait_ref.with_self_ty(*self.tcx, ty);
let trait_ref = self.tcx.erase_regions(trait_ref);
- self.tcx.vtable_methods(trait_ref)
+ self.tcx.vtable_entries(trait_ref)
} else {
- &[]
+ COMMON_VTABLE_ENTRIES
};
let layout = self.layout_of(ty)?;
@@ -56,38 +59,41 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
// If you touch this code, be sure to also make the corresponding changes to
// `get_vtable` in `rust_codegen_llvm/meth.rs`.
// /////////////////////////////////////////////////////////////////////////////////////////
- let vtable_size = ptr_size * u64::try_from(methods.len()).unwrap().checked_add(3).unwrap();
+ let vtable_size = ptr_size * u64::try_from(vtable_entries.len()).unwrap();
let vtable = self.memory.allocate(vtable_size, ptr_align, MemoryKind::Vtable);
let drop = Instance::resolve_drop_in_place(tcx, ty);
let drop = self.memory.create_fn_alloc(FnVal::Instance(drop));
- // Prepare the fn ptrs we will write into the vtable later.
- let fn_ptrs = methods
- .iter()
- .enumerate() // remember the original position
- .filter_map(|(i, method)| {
- if let Some((def_id, substs)) = method { Some((i, def_id, substs)) } else { None }
- })
- .map(|(i, def_id, substs)| {
- let instance =
- ty::Instance::resolve_for_vtable(tcx, self.param_env, *def_id, substs)
- .ok_or_else(|| err_inval!(TooGeneric))?;
- Ok((i, self.memory.create_fn_alloc(FnVal::Instance(instance))))
- })
- .collect::<InterpResult<'tcx, Vec<(usize, Pointer<M::PointerTag>)>>>()?;
-
// No need to do any alignment checks on the memory accesses below, because we know the
// allocation is correctly aligned as we created it above. Also we're only offsetting by
// multiples of `ptr_align`, which means that it will stay aligned to `ptr_align`.
+ let scalars = vtable_entries
+ .iter()
+ .map(|entry| -> InterpResult<'tcx, _> {
+ match entry {
+ VtblEntry::MetadataDropInPlace => Ok(Some(drop.into())),
+ VtblEntry::MetadataSize => Ok(Some(Scalar::from_uint(size, ptr_size).into())),
+ VtblEntry::MetadataAlign => Ok(Some(Scalar::from_uint(align, ptr_size).into())),
+ VtblEntry::Vacant => Ok(None),
+ VtblEntry::Method(def_id, substs) => {
+ // Prepare the fn ptr we write into the vtable.
+ let instance =
+ ty::Instance::resolve_for_vtable(tcx, self.param_env, *def_id, substs)
+ .ok_or_else(|| err_inval!(TooGeneric))?;
+ let fn_ptr = self.memory.create_fn_alloc(FnVal::Instance(instance));
+ Ok(Some(fn_ptr.into()))
+ }
+ }
+ })
+ .collect::<Result<Vec<_>, _>>()?;
let mut vtable_alloc =
self.memory.get_mut(vtable.into(), vtable_size, ptr_align)?.expect("not a ZST");
- vtable_alloc.write_ptr_sized(ptr_size * 0, drop.into())?;
- vtable_alloc.write_ptr_sized(ptr_size * 1, Scalar::from_uint(size, ptr_size).into())?;
- vtable_alloc.write_ptr_sized(ptr_size * 2, Scalar::from_uint(align, ptr_size).into())?;
-
- for (i, fn_ptr) in fn_ptrs.into_iter() {
- vtable_alloc.write_ptr_sized(ptr_size * (3 + i as u64), fn_ptr.into())?;
+ for (idx, scalar) in scalars.into_iter().enumerate() {
+ if let Some(scalar) = scalar {
+ let idx: u64 = u64::try_from(idx).unwrap();
+ vtable_alloc.write_ptr_sized(ptr_size * idx, scalar)?;
+ }
}
M::after_static_mem_initialized(self, vtable, vtable_size)?;
@@ -99,16 +105,15 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
}
/// Resolves the function at the specified slot in the provided
- /// vtable. An index of '0' corresponds to the first method
- /// declared in the trait of the provided vtable.
+ /// vtable. Currently an index of '3' (`COMMON_VTABLE_ENTRIES.len()`)
+ /// corresponds to the first method declared in the trait of the provided vtable.
pub fn get_vtable_slot(
&self,
vtable: Scalar<M::PointerTag>,
idx: u64,
) -> InterpResult<'tcx, FnVal<'tcx, M::ExtraFnVal>> {
let ptr_size = self.pointer_size();
- // Skip over the 'drop_ptr', 'size', and 'align' fields.
- let vtable_slot = vtable.ptr_offset(ptr_size * idx.checked_add(3).unwrap(), self)?;
+ let vtable_slot = vtable.ptr_offset(ptr_size * idx, self)?;
let vtable_slot = self
.memory
.get(vtable_slot, ptr_size, self.tcx.data_layout.pointer_align.abi)?
@@ -122,12 +127,21 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
&self,
vtable: Scalar<M::PointerTag>,
) -> InterpResult<'tcx, (ty::Instance<'tcx>, Ty<'tcx>)> {
+ let pointer_size = self.pointer_size();
// We don't care about the pointee type; we just want a pointer.
let vtable = self
.memory
- .get(vtable, self.tcx.data_layout.pointer_size, self.tcx.data_layout.pointer_align.abi)?
+ .get(
+ vtable,
+ pointer_size * u64::try_from(COMMON_VTABLE_ENTRIES.len()).unwrap(),
+ self.tcx.data_layout.pointer_align.abi,
+ )?
.expect("cannot be a ZST");
- let drop_fn = vtable.read_ptr_sized(Size::ZERO)?.check_init()?;
+ let drop_fn = vtable
+ .read_ptr_sized(
+ pointer_size * u64::try_from(COMMON_VTABLE_ENTRIES_DROPINPLACE).unwrap(),
+ )?
+ .check_init()?;
// We *need* an instance here, no other kind of function value, to be able
// to determine the type.
let drop_instance = self.memory.get_fn(drop_fn)?.as_instance()?;
@@ -153,11 +167,19 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
// the size, and the align (which we read below).
let vtable = self
.memory
- .get(vtable, 3 * pointer_size, self.tcx.data_layout.pointer_align.abi)?
+ .get(
+ vtable,
+ pointer_size * u64::try_from(COMMON_VTABLE_ENTRIES.len()).unwrap(),
+ self.tcx.data_layout.pointer_align.abi,
+ )?
.expect("cannot be a ZST");
- let size = vtable.read_ptr_sized(pointer_size)?.check_init()?;
+ let size = vtable
+ .read_ptr_sized(pointer_size * u64::try_from(COMMON_VTABLE_ENTRIES_SIZE).unwrap())?
+ .check_init()?;
let size = u64::try_from(self.force_bits(size, pointer_size)?).unwrap();
- let align = vtable.read_ptr_sized(pointer_size * 2)?.check_init()?;
+ let align = vtable
+ .read_ptr_sized(pointer_size * u64::try_from(COMMON_VTABLE_ENTRIES_ALIGN).unwrap())?
+ .check_init()?;
let align = u64::try_from(self.force_bits(align, pointer_size)?).unwrap();
let align = Align::from_bytes(align).map_err(|e| err_ub!(InvalidVtableAlignment(e)))?;
diff --git a/compiler/rustc_mir/src/monomorphize/collector.rs b/compiler/rustc_mir/src/monomorphize/collector.rs
index 31cb5484bcefb..0ab9aa8e1bfd4 100644
--- a/compiler/rustc_mir/src/monomorphize/collector.rs
+++ b/compiler/rustc_mir/src/monomorphize/collector.rs
@@ -196,7 +196,7 @@ use rustc_middle::mir::{self, Local, Location};
use rustc_middle::ty::adjustment::{CustomCoerceUnsized, PointerCast};
use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts};
-use rustc_middle::ty::{self, GenericParamDefKind, Instance, Ty, TyCtxt, TypeFoldable};
+use rustc_middle::ty::{self, GenericParamDefKind, Instance, Ty, TyCtxt, TypeFoldable, VtblEntry};
use rustc_middle::{middle::codegen_fn_attrs::CodegenFnAttrFlags, mir::visit::TyContext};
use rustc_session::config::EntryFnType;
use rustc_session::lint::builtin::LARGE_ASSIGNMENTS;
@@ -1091,21 +1091,22 @@ fn create_mono_items_for_vtable_methods<'tcx>(
assert!(!poly_trait_ref.has_escaping_bound_vars());
// Walk all methods of the trait, including those of its supertraits
- let methods = tcx.vtable_methods(poly_trait_ref);
- let methods = methods
+ let entries = tcx.vtable_entries(poly_trait_ref);
+ let methods = entries
.iter()
- .cloned()
- .filter_map(|method| method)
- .map(|(def_id, substs)| {
- ty::Instance::resolve_for_vtable(
+ .filter_map(|entry| match entry {
+ VtblEntry::MetadataDropInPlace
+ | VtblEntry::MetadataSize
+ | VtblEntry::MetadataAlign
+ | VtblEntry::Vacant => None,
+ VtblEntry::Method(def_id, substs) => ty::Instance::resolve_for_vtable(
tcx,
ty::ParamEnv::reveal_all(),
- def_id,
+ *def_id,
substs,
)
- .unwrap()
+ .filter(|instance| should_codegen_locally(tcx, instance)),
})
- .filter(|&instance| should_codegen_locally(tcx, &instance))
.map(|item| create_fn_mono_item(tcx, item, source));
output.extend(methods);
}
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index f26eb159105d7..d65a596a8276f 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -31,7 +31,8 @@ use rustc_hir::def_id::DefId;
use rustc_middle::ty::fold::TypeFoldable;
use rustc_middle::ty::subst::{InternalSubsts, SubstsRef};
use rustc_middle::ty::{
- self, GenericParamDefKind, ParamEnv, ToPredicate, Ty, TyCtxt, WithConstness,
+ self, GenericParamDefKind, ParamEnv, ToPredicate, Ty, TyCtxt, VtblEntry, WithConstness,
+ COMMON_VTABLE_ENTRIES,
};
use rustc_span::Span;
@@ -455,59 +456,89 @@ fn subst_and_check_impossible_predicates<'tcx>(
/// Given a trait `trait_ref`, iterates the vtable entries
/// that come from `trait_ref`, including its supertraits.
-fn vtable_methods<'tcx>(
+fn vtable_entries<'tcx>(
tcx: TyCtxt<'tcx>,
trait_ref: ty::PolyTraitRef<'tcx>,
-) -> &'tcx [Option<(DefId, SubstsRef<'tcx>)>] {
- debug!("vtable_methods({:?})", trait_ref);
-
- tcx.arena.alloc_from_iter(supertraits(tcx, trait_ref).flat_map(move |trait_ref| {
- let trait_methods = tcx
- .associated_items(trait_ref.def_id())
- .in_definition_order()
- .filter(|item| item.kind == ty::AssocKind::Fn);
-
- // Now list each method's DefId and InternalSubsts (for within its trait).
- // If the method can never be called from this object, produce None.
- trait_methods.map(move |trait_method| {
- debug!("vtable_methods: trait_method={:?}", trait_method);
- let def_id = trait_method.def_id;
-
- // Some methods cannot be called on an object; skip those.
- if !is_vtable_safe_method(tcx, trait_ref.def_id(), &trait_method) {
- debug!("vtable_methods: not vtable safe");
- return None;
- }
+) -> &'tcx [VtblEntry<'tcx>] {
+ debug!("vtable_entries({:?})", trait_ref);
+
+ let entries = COMMON_VTABLE_ENTRIES.iter().cloned().chain(
+ supertraits(tcx, trait_ref).flat_map(move |trait_ref| {
+ let trait_methods = tcx
+ .associated_items(trait_ref.def_id())
+ .in_definition_order()
+ .filter(|item| item.kind == ty::AssocKind::Fn);
+
+ // Now list each method's DefId and InternalSubsts (for within its trait).
+ // If the method can never be called from this object, produce `Vacant`.
+ trait_methods.map(move |trait_method| {
+ debug!("vtable_entries: trait_method={:?}", trait_method);
+ let def_id = trait_method.def_id;
+
+ // Some methods cannot be called on an object; skip those.
+ if !is_vtable_safe_method(tcx, trait_ref.def_id(), &trait_method) {
+ debug!("vtable_entries: not vtable safe");
+ return VtblEntry::Vacant;
+ }
- // The method may have some early-bound lifetimes; add regions for those.
- let substs = trait_ref.map_bound(|trait_ref| {
- InternalSubsts::for_item(tcx, def_id, |param, _| match param.kind {
- GenericParamDefKind::Lifetime => tcx.lifetimes.re_erased.into(),
- GenericParamDefKind::Type { .. } | GenericParamDefKind::Const { .. } => {
- trait_ref.substs[param.index as usize]
- }
- })
- });
-
- // The trait type may have higher-ranked lifetimes in it;
- // erase them if they appear, so that we get the type
- // at some particular call site.
- let substs =
- tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), substs);
-
- // It's possible that the method relies on where-clauses that
- // do not hold for this particular set of type parameters.
- // Note that this method could then never be called, so we
- // do not want to try and codegen it, in that case (see #23435).
- let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, substs);
- if impossible_predicates(tcx, predicates.predicates) {
- debug!("vtable_methods: predicates do not hold");
- return None;
- }
+ // The method may have some early-bound lifetimes; add regions for those.
+ let substs = trait_ref.map_bound(|trait_ref| {
+ InternalSubsts::for_item(tcx, def_id, |param, _| match param.kind {
+ GenericParamDefKind::Lifetime => tcx.lifetimes.re_erased.into(),
+ GenericParamDefKind::Type { .. } | GenericParamDefKind::Const { .. } => {
+ trait_ref.substs[param.index as usize]
+ }
+ })
+ });
+
+ // The trait type may have higher-ranked lifetimes in it;
+ // erase them if they appear, so that we get the type
+ // at some particular call site.
+ let substs =
+ tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), substs);
+
+ // It's possible that the method relies on where-clauses that
+ // do not hold for this particular set of type parameters.
+ // Note that this method could then never be called, so we
+ // do not want to try and codegen it, in that case (see #23435).
+ let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, substs);
+ if impossible_predicates(tcx, predicates.predicates) {
+ debug!("vtable_entries: predicates do not hold");
+ return VtblEntry::Vacant;
+ }
- Some((def_id, substs))
- })
- }))
+ VtblEntry::Method(def_id, substs)
+ })
+ }),
+ );
+
+ tcx.arena.alloc_from_iter(entries)
+}
+
+/// Find slot base for trait methods within vtable entries of another trait
+fn vtable_trait_first_method_offset<'tcx>(
+ tcx: TyCtxt<'tcx>,
+ key: (
+ ty::PolyTraitRef<'tcx>, // trait_to_be_found
+ ty::PolyTraitRef<'tcx>, // trait_owning_vtable
+ ),
+) -> usize {
+ let (trait_to_be_found, trait_owning_vtable) = key;
+
+ let mut supertraits = util::supertraits(tcx, trait_owning_vtable);
+
+ // For each of the non-matching predicates that
+ // we pass over, we sum up the set of number of vtable
+ // entries, so that we can compute the offset for the selected
+ // trait.
+ let vtable_base = ty::COMMON_VTABLE_ENTRIES.len()
+ + supertraits
+ .by_ref()
+ .take_while(|t| *t != trait_to_be_found)
+ .map(|t| util::count_own_vtable_entries(tcx, t))
+ .sum::<usize>();
+
+ vtable_base
}
/// Check whether a `ty` implements given trait(trait_def_id).
@@ -547,7 +578,7 @@ pub fn provide(providers: &mut ty::query::Providers) {
specialization_graph_of: specialize::specialization_graph_provider,
specializes: specialize::specializes,
codegen_fulfill_obligation: codegen::codegen_fulfill_obligation,
- vtable_methods,
+ vtable_entries,
type_implements_trait,
subst_and_check_impossible_predicates,
mir_abstract_const: |tcx, def_id| {
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index e338a21b60308..f8297ee3a0718 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -396,19 +396,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
let mut nested = vec![];
let mut supertraits = util::supertraits(tcx, ty::Binder::dummy(object_trait_ref));
-
- // For each of the non-matching predicates that
- // we pass over, we sum up the set of number of vtable
- // entries, so that we can compute the offset for the selected
- // trait.
- let vtable_base = supertraits
- .by_ref()
- .take(index)
- .map(|t| super::util::count_own_vtable_entries(tcx, t))
- .sum();
-
let unnormalized_upcast_trait_ref =
- supertraits.next().expect("supertraits iterator no longer has as many elements");
+ supertraits.nth(index).expect("supertraits iterator no longer has as many elements");
let upcast_trait_ref = normalize_with_depth_to(
self,
@@ -490,6 +479,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
debug!(?nested, "object nested obligations");
+
+ let vtable_base = super::super::vtable_trait_first_method_offset(
+ tcx,
+ (unnormalized_upcast_trait_ref, ty::Binder::dummy(object_trait_ref)),
+ );
+
Ok(ImplSourceObjectData { upcast_trait_ref, vtable_base, nested })
}