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fix ices on vfe about principal trait

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This commit is contained in:
Luv-Ray 2024-09-23 15:25:52 +08:00
parent c0838c8ebe
commit 16093faea8
7 changed files with 61 additions and 51 deletions
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9
compiler/rustc_codegen_ssa/src/base.rs
View File

@ -37,6 +37,7 @@
submit_post_lto_module_to_llvm, submit_pre_lto_module_to_llvm, ComputedLtoType, OngoingCodegen,
};
use crate::common::{self, IntPredicate, RealPredicate, TypeKind};
use crate::meth::load_vtable;
use crate::mir::operand::OperandValue;
use crate::mir::place::PlaceRef;
use crate::traits::*;
@ -135,14 +136,8 @@ fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
if let Some(entry_idx) = vptr_entry_idx {
let ptr_size = bx.data_layout().pointer_size;
let ptr_align = bx.data_layout().pointer_align.abi;
let vtable_byte_offset = u64::try_from(entry_idx).unwrap() * ptr_size.bytes();
let gep = bx.inbounds_ptradd(old_info, bx.const_usize(vtable_byte_offset));
let new_vptr = bx.load(bx.type_ptr(), gep, ptr_align);
bx.nonnull_metadata(new_vptr);
// VTable loads are invariant.
bx.set_invariant_load(new_vptr);
new_vptr
load_vtable(bx, old_info, bx.type_ptr(), vtable_byte_offset, source, true)
} else {
old_info
}

67
compiler/rustc_codegen_ssa/src/meth.rs
View File

@ -28,27 +28,9 @@ fn get_fn_inner<Bx: BuilderMethods<'a, 'tcx>>(
let llty = bx.fn_ptr_backend_type(fn_abi);
let ptr_size = bx.data_layout().pointer_size;
let ptr_align = bx.data_layout().pointer_align.abi;
let vtable_byte_offset = self.0 * ptr_size.bytes();
if bx.cx().sess().opts.unstable_opts.virtual_function_elimination
&& bx.cx().sess().lto() == Lto::Fat
{
let typeid = bx
.typeid_metadata(typeid_for_trait_ref(bx.tcx(), expect_dyn_trait_in_self(ty)))
.unwrap();
let func = bx.type_checked_load(llvtable, vtable_byte_offset, typeid);
func
} else {
let gep = bx.inbounds_ptradd(llvtable, bx.const_usize(vtable_byte_offset));
let ptr = bx.load(llty, gep, ptr_align);
// VTable loads are invariant.
bx.set_invariant_load(ptr);
if nonnull {
bx.nonnull_metadata(ptr);
}
ptr
}
load_vtable(bx, llvtable, llty, vtable_byte_offset, ty, nonnull)
}
pub(crate) fn get_optional_fn<Bx: BuilderMethods<'a, 'tcx>>(
@ -75,31 +57,27 @@ pub(crate) fn get_usize<Bx: BuilderMethods<'a, 'tcx>>(
self,
bx: &mut Bx,
llvtable: Bx::Value,
ty: Ty<'tcx>,
) -> Bx::Value {
// Load the data pointer from the object.
debug!("get_int({:?}, {:?})", llvtable, self);
let llty = bx.type_isize();
let ptr_size = bx.data_layout().pointer_size;
let ptr_align = bx.data_layout().pointer_align.abi;
let vtable_byte_offset = self.0 * ptr_size.bytes();
let gep = bx.inbounds_ptradd(llvtable, bx.const_usize(vtable_byte_offset));
let ptr = bx.load(llty, gep, ptr_align);
// VTable loads are invariant.
bx.set_invariant_load(ptr);
ptr
load_vtable(bx, llvtable, llty, vtable_byte_offset, ty, false)
}
}
/// This takes a valid `self` receiver type and extracts the principal trait
/// ref of the type.
fn expect_dyn_trait_in_self(ty: Ty<'_>) -> ty::PolyExistentialTraitRef<'_> {
/// ref of the type. Return `None` if there is no principal trait.
fn dyn_trait_in_self(ty: Ty<'_>) -> Option<ty::PolyExistentialTraitRef<'_>> {
for arg in ty.peel_refs().walk() {
if let GenericArgKind::Type(ty) = arg.unpack()
&& let ty::Dynamic(data, _, _) = ty.kind()
{
return data.principal().expect("expected principal trait object");
return data.principal();
}
}
@ -138,3 +116,36 @@ pub(crate) fn get_vtable<'tcx, Cx: CodegenMethods<'tcx>>(
cx.vtables().borrow_mut().insert((ty, trait_ref), vtable);
vtable
}
/// Call this function whenever you need to load a vtable.
pub(crate) fn load_vtable<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
llvtable: Bx::Value,
llty: Bx::Type,
vtable_byte_offset: u64,
ty: Ty<'tcx>,
nonnull: bool,
) -> Bx::Value {
let ptr_align = bx.data_layout().pointer_align.abi;
if bx.cx().sess().opts.unstable_opts.virtual_function_elimination
&& bx.cx().sess().lto() == Lto::Fat
{
if let Some(trait_ref) = dyn_trait_in_self(ty) {
let typeid = bx.typeid_metadata(typeid_for_trait_ref(bx.tcx(), trait_ref)).unwrap();
let func = bx.type_checked_load(llvtable, vtable_byte_offset, typeid);
return func;
} else if nonnull {
bug!("load nonnull value from a vtable without a principal trait")
}
}
let gep = bx.inbounds_ptradd(llvtable, bx.const_usize(vtable_byte_offset));
let ptr = bx.load(llty, gep, ptr_align);
// VTable loads are invariant.
bx.set_invariant_load(ptr);
if nonnull {
bx.nonnull_metadata(ptr);
}
ptr
}

2
compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
View File

@ -126,7 +126,7 @@ pub fn codegen_intrinsic_call(
sym::vtable_align => ty::COMMON_VTABLE_ENTRIES_ALIGN,
_ => bug!(),
};
let value = meth::VirtualIndex::from_index(idx).get_usize(bx, vtable);
let value = meth::VirtualIndex::from_index(idx).get_usize(bx, vtable, callee_ty);
match name {
// Size is always <= isize::MAX.
sym::vtable_size => {

4
compiler/rustc_codegen_ssa/src/size_of_val.rs
View File

@ -28,9 +28,9 @@ pub fn size_and_align_of_dst<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
// Load size/align from vtable.
let vtable = info.unwrap();
let size = meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_SIZE)
.get_usize(bx, vtable);
.get_usize(bx, vtable, t);
let align = meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_ALIGN)
.get_usize(bx, vtable);
.get_usize(bx, vtable, t);
// Size is always <= isize::MAX.
let size_bound = bx.data_layout().ptr_sized_integer().signed_max() as u128;

6
tests/crashes/123955.rs
View File

@ -1,6 +0,0 @@
//@ known-bug: #123955
//@ compile-flags: -Clto -Zvirtual-function-elimination
//@ only-x86_64
pub fn main() {
_ = Box::new(()) as Box<dyn Send>;
}

7
tests/crashes/124092.rs
View File

@ -1,7 +0,0 @@
//@ known-bug: #124092
//@ compile-flags: -Zvirtual-function-elimination=true -Clto=true
//@ only-x86_64
const X: for<'b> fn(&'b ()) = |&()| ();
fn main() {
let dyn_debug = Box::new(X) as Box<fn(&'static ())> as Box<dyn Send>;
}

17
tests/ui/codegen/virtual-function-elimination.rs Normal file
View File

@ -0,0 +1,17 @@
//@ build-pass
//@ compile-flags: -Zvirtual-function-elimination=true -Clto=true
//@ only-x86_64
//@ no-prefer-dynamic
// issue #123955
pub fn test0() {
_ = Box::new(()) as Box<dyn Send>;
}
// issue #124092
const X: for<'b> fn(&'b ()) = |&()| ();
pub fn test1() {
let _dyn_debug = Box::new(X) as Box<fn(&'static ())> as Box<dyn Send>;
}
fn main() {}