bjoernager/rust
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Introduce ConstAllocation.

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Currently some `Allocation`s are interned, some are not, and it's very
hard to tell at a use point which is which.

This commit introduces `ConstAllocation` for the known-interned ones,
which makes the division much clearer. `ConstAllocation::inner()` is
used to get the underlying `Allocation`.

In some places it's natural to use an `Allocation`, in some it's natural
to use a `ConstAllocation`, and in some places there's no clear choice.
I've tried to make things look as nice as possible, while generally
favouring `ConstAllocation`, which is the type that embodies more
information. This does require quite a few calls to `inner()`.

The commit also tweaks how `PartialOrd` works for `Interned`. The
previous code was too clever by half, building on `T: Ord` to make the
code shorter. That caused problems with deriving `PartialOrd` and `Ord`
for `ConstAllocation`, so I changed it to build on `T: PartialOrd`,
which is slightly more verbose but much more standard and avoided the
problems.
This commit is contained in:
Nicholas Nethercote 2022-03-02 07:15:04 +11:00
parent c38b8a8c62
commit 4852291417
30 changed files with 166 additions and 119 deletions
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13
compiler/rustc_codegen_gcc/src/common.rs
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@ -13,7 +13,7 @@ use rustc_codegen_ssa::traits::{
use rustc_middle::mir::Mutability;
use rustc_middle::ty::ScalarInt;
use rustc_middle::ty::layout::{TyAndLayout, LayoutOf};
use rustc_middle::mir::interpret::{Allocation, GlobalAlloc, Scalar};
use rustc_middle::mir::interpret::{ConstAllocation, GlobalAlloc, Scalar};
use rustc_span::Symbol;
use rustc_target::abi::{self, HasDataLayout, Pointer, Size};
@ -230,6 +230,7 @@ impl<'gcc, 'tcx> ConstMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
match self.tcx.global_alloc(alloc_id) {
GlobalAlloc::Memory(alloc) => {
let init = const_alloc_to_gcc(self, alloc);
let alloc = alloc.inner();
let value =
match alloc.mutability {
Mutability::Mut => self.static_addr_of_mut(init, alloc.align, None),
@ -262,21 +263,21 @@ impl<'gcc, 'tcx> ConstMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
}
}
fn const_data_from_alloc(&self, alloc: &Allocation) -> Self::Value {
fn const_data_from_alloc(&self, alloc: ConstAllocation<'tcx>) -> Self::Value {
const_alloc_to_gcc(self, alloc)
}
fn from_const_alloc(&self, layout: TyAndLayout<'tcx>, alloc: &Allocation, offset: Size) -> PlaceRef<'tcx, RValue<'gcc>> {
assert_eq!(alloc.align, layout.align.abi);
fn from_const_alloc(&self, layout: TyAndLayout<'tcx>, alloc: ConstAllocation<'tcx>, offset: Size) -> PlaceRef<'tcx, RValue<'gcc>> {
assert_eq!(alloc.inner().align, layout.align.abi);
let ty = self.type_ptr_to(layout.gcc_type(self, true));
let value =
if layout.size == Size::ZERO {
let value = self.const_usize(alloc.align.bytes());
let value = self.const_usize(alloc.inner().align.bytes());
self.context.new_cast(None, value, ty)
}
else {
let init = const_alloc_to_gcc(self, alloc);
let base_addr = self.static_addr_of(init, alloc.align, None);
let base_addr = self.static_addr_of(init, alloc.inner().align, None);
let array = self.const_bitcast(base_addr, self.type_i8p());
let value = self.context.new_array_access(None, array, self.const_usize(offset.bytes())).get_address(None);