From c39af6e79b135ed0462b5cb11eb530cbd07facad Mon Sep 17 00:00:00 2001
From: Eduard-Mihai Burtescu <edy.burt@gmail.com>
Date: Tue, 15 Oct 2019 22:11:39 +0300
Subject: [PATCH] rustc_codegen_ssa: remove some unnecessary Box
special-casing.
---
src/librustc_codegen_ssa/base.rs | 46 +++++++++++++-------------------
1 file changed, 19 insertions(+), 27 deletions(-)
diff --git a/src/librustc_codegen_ssa/base.rs b/src/librustc_codegen_ssa/base.rs
index 1c441ca7cbf2e..5f2d17f28c258 100644
--- a/src/librustc_codegen_ssa/base.rs
+++ b/src/librustc_codegen_ssa/base.rs
@@ -168,12 +168,6 @@ pub fn unsize_thin_ptr<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
let ptr_ty = bx.cx().type_ptr_to(bx.cx().backend_type(bx.cx().layout_of(b)));
(bx.pointercast(src, ptr_ty), unsized_info(bx.cx(), a, b, None))
}
- (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) if def_a.is_box() && def_b.is_box() => {
- let (a, b) = (src_ty.boxed_ty(), dst_ty.boxed_ty());
- assert!(bx.cx().type_is_sized(a));
- let ptr_ty = bx.cx().type_ptr_to(bx.cx().backend_type(bx.cx().layout_of(b)));
- (bx.pointercast(src, ptr_ty), unsized_info(bx.cx(), a, b, None))
- }
(&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
assert_eq!(def_a, def_b);
@@ -196,6 +190,8 @@ pub fn unsize_thin_ptr<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
}
let (lldata, llextra) = result.unwrap();
// HACK(eddyb) have to bitcast pointers until LLVM removes pointee types.
+ // FIXME(eddyb) move these out of this `match` arm, so they're always
+ // applied, uniformly, no matter the source/destination types.
(bx.bitcast(lldata, bx.cx().scalar_pair_element_backend_type(dst_layout, 0, true)),
bx.bitcast(llextra, bx.cx().scalar_pair_element_backend_type(dst_layout, 1, true)))
}
@@ -212,31 +208,27 @@ pub fn coerce_unsized_into<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
) {
let src_ty = src.layout.ty;
let dst_ty = dst.layout.ty;
- let mut coerce_ptr = || {
- let (base, info) = match bx.load_operand(src).val {
- OperandValue::Pair(base, info) => {
- // fat-ptr to fat-ptr unsize preserves the vtable
- // i.e., &'a fmt::Debug+Send => &'a fmt::Debug
- // So we need to pointercast the base to ensure
- // the types match up.
- let thin_ptr = dst.layout.field(bx.cx(), FAT_PTR_ADDR);
- (bx.pointercast(base, bx.cx().backend_type(thin_ptr)), info)
- }
- OperandValue::Immediate(base) => {
- unsize_thin_ptr(bx, base, src_ty, dst_ty)
- }
- OperandValue::Ref(..) => bug!()
- };
- OperandValue::Pair(base, info).store(bx, dst);
- };
match (&src_ty.kind, &dst_ty.kind) {
(&ty::Ref(..), &ty::Ref(..)) |
(&ty::Ref(..), &ty::RawPtr(..)) |
(&ty::RawPtr(..), &ty::RawPtr(..)) => {
- coerce_ptr()
- }
- (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) if def_a.is_box() && def_b.is_box() => {
- coerce_ptr()
+ let (base, info) = match bx.load_operand(src).val {
+ OperandValue::Pair(base, info) => {
+ // fat-ptr to fat-ptr unsize preserves the vtable
+ // i.e., &'a fmt::Debug+Send => &'a fmt::Debug
+ // So we need to pointercast the base to ensure
+ // the types match up.
+ // FIXME(eddyb) use `scalar_pair_element_backend_type` here,
+ // like `unsize_thin_ptr` does.
+ let thin_ptr = dst.layout.field(bx.cx(), FAT_PTR_ADDR);
+ (bx.pointercast(base, bx.cx().backend_type(thin_ptr)), info)
+ }
+ OperandValue::Immediate(base) => {
+ unsize_thin_ptr(bx, base, src_ty, dst_ty)
+ }
+ OperandValue::Ref(..) => bug!()
+ };
+ OperandValue::Pair(base, info).store(bx, dst);
}
(&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {