bjoernager/rust
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Auto merge of #77947 - tmiasko:promoted-scope, r=oli-obk

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Create a single source scope for promoteds

A promoted inherits all scopes from the parent body.  At the same time,
almost all statements and terminators inside the promoted body so far
refer only to one of those scopes: the outermost one.

Instead of inheriting all scopes, inherit only a single scope
corresponding to the location of the promoted, making sure that there
are no references to other scopes.
This commit is contained in:
bors 2020-10-16 02:27:49 +00:00
commit 9bd740a8f1
2 changed files with 14 additions and 5 deletions
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17
compiler/rustc_mir/src/transform/promote_consts.rs
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@ -124,6 +124,15 @@ impl Candidate {
Candidate::Argument { .. } | Candidate::InlineAsm { .. } => true,
}
}
fn source_info(&self, body: &Body<'_>) -> SourceInfo {
match self {
Candidate::Ref(location) | Candidate::Repeat(location) => *body.source_info(*location),
Candidate::Argument { bb, .. } | Candidate::InlineAsm { bb, .. } => {
*body.source_info(body.terminator_loc(*bb))
}
}
}
}
fn args_required_const(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Vec<usize>> {
@ -953,6 +962,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
from_hir_call,
fn_span,
},
source_info: SourceInfo::outermost(terminator.source_info.span),
..terminator
};
}
@ -1163,12 +1173,13 @@ pub fn promote_candidates<'tcx>(
// Declare return place local so that `mir::Body::new` doesn't complain.
let initial_locals = iter::once(LocalDecl::new(tcx.types.never, body.span)).collect();
let mut scope = body.source_scopes[candidate.source_info(body).scope].clone();
scope.parent_scope = None;
let mut promoted = Body::new(
body.source, // `promoted` gets filled in below
IndexVec::new(),
// FIXME: maybe try to filter this to avoid blowing up
// memory usage?
body.source_scopes.clone(),
IndexVec::from_elem_n(scope, 1),
initial_locals,
IndexVec::new(),
0,