bjoernager/rust
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inliner: Use substs_for_mir_body

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Changes from 68965 extended the kind of instances that are being
inlined. For some of those, the `instance_mir` returns a MIR body that
is already expressed in terms of the types found in substitution array,
and doesn't need further substitution.

Use `substs_for_mir_body` to take that into account.
This commit is contained in:
Tomasz Miąsko 2020-11-06 00:00:00 +00:00
parent 9d78d1d027
commit 8a8ee1a3ed
9 changed files with 142 additions and 42 deletions
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27
compiler/rustc_middle/src/ty/instance.rs
View file

@ -1,6 +1,6 @@
use crate::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use crate::ty::print::{FmtPrinter, Printer};
use crate::ty::subst::InternalSubsts;
use crate::ty::subst::{InternalSubsts, Subst};
use crate::ty::{self, SubstsRef, Ty, TyCtxt, TypeFoldable};
use rustc_errors::ErrorReported;
use rustc_hir::def::Namespace;
@ -470,10 +470,33 @@ impl<'tcx> Instance<'tcx> {
/// This function returns `Some(substs)` in the former case and `None` otherwise -- i.e., if
/// this function returns `None`, then the MIR body does not require substitution during
/// codegen.
pub fn substs_for_mir_body(&self) -> Option<SubstsRef<'tcx>> {
fn substs_for_mir_body(&self) -> Option<SubstsRef<'tcx>> {
if self.def.has_polymorphic_mir_body() { Some(self.substs) } else { None }
}
pub fn subst_mir<T>(&self, tcx: TyCtxt<'tcx>, v: &T) -> T
where
T: TypeFoldable<'tcx> + Copy,
{
if let Some(substs) = self.substs_for_mir_body() { v.subst(tcx, substs) } else { *v }
}
pub fn subst_mir_and_normalize_erasing_regions<T>(
&self,
tcx: TyCtxt<'tcx>,
param_env: ty::ParamEnv<'tcx>,
v: &T,
) -> T
where
T: TypeFoldable<'tcx> + Clone,
{
if let Some(substs) = self.substs_for_mir_body() {
tcx.subst_and_normalize_erasing_regions(substs, param_env, v)
} else {
tcx.normalize_erasing_regions(param_env, v.clone())
}
}
/// Returns a new `Instance` where generic parameters in `instance.substs` are replaced by
/// identify parameters if they are determined to be unused in `instance.def`.
pub fn polymorphize(self, tcx: TyCtxt<'tcx>) -> Self {