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Auto merge of #76071 - khyperia:configurable_to_immediate, r=eddyb

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Make to_immediate/from_immediate configurable by backends

`librustc_codegen_ssa` has the concept of an immediate vs. memory type, and `librustc_codegen_llvm` uses this distinction to implement `bool`s being `i8` in memory, and `i1` in immediate contexts. However, some of that implementation leaked into `codegen_ssa` when converting to/from immediate values. So, move those methods into builder traits, so that behavior can be configured by backends.

This is useful if a backend is able to keep bools as bools, or, needs to do more trickery than just bools to bytes.

(Note that there's already a large amount of things abstracted with "immediate types" - this is just bringing this particular thing in line to be abstracted as well)

---

Pinging @eddyb since that's who I was talking about this change with when they suggested I submit a PR.
This commit is contained in:
bors 2020-09-01 07:44:34 +00:00
commit 6f1bbf5ee0
7 changed files with 56 additions and 68 deletions
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33
compiler/rustc_codegen_ssa/src/base.rs
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@ -38,7 +38,7 @@ use rustc_middle::middle::cstore::EncodedMetadata;
use rustc_middle::middle::cstore::{self, LinkagePreference};
use rustc_middle::middle::lang_items;
use rustc_middle::mir::mono::{CodegenUnit, CodegenUnitNameBuilder, MonoItem};
use rustc_middle::ty::layout::{self, HasTyCtxt, TyAndLayout};
use rustc_middle::ty::layout::{HasTyCtxt, TyAndLayout};
use rustc_middle::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
@ -48,7 +48,7 @@ use rustc_session::utils::NativeLibKind;
use rustc_session::Session;
use rustc_span::Span;
use rustc_symbol_mangling::test as symbol_names_test;
use rustc_target::abi::{Abi, Align, LayoutOf, Scalar, VariantIdx};
use rustc_target::abi::{Align, LayoutOf, VariantIdx};
use std::cmp;
use std::ops::{Deref, DerefMut};
@ -330,35 +330,6 @@ pub fn wants_msvc_seh(sess: &Session) -> bool {
sess.target.target.options.is_like_msvc
}
pub fn from_immediate<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
val: Bx::Value,
) -> Bx::Value {
if bx.cx().val_ty(val) == bx.cx().type_i1() { bx.zext(val, bx.cx().type_i8()) } else { val }
}
pub fn to_immediate<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
val: Bx::Value,
layout: layout::TyAndLayout<'_>,
) -> Bx::Value {
if let Abi::Scalar(ref scalar) = layout.abi {
return to_immediate_scalar(bx, val, scalar);
}
val
}
pub fn to_immediate_scalar<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
val: Bx::Value,
scalar: &Scalar,
) -> Bx::Value {
if scalar.is_bool() {
return bx.trunc(val, bx.cx().type_i1());
}
val
}
pub fn memcpy_ty<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
bx: &mut Bx,
dst: Bx::Value,