bjoernager/rust
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Ensure nested allocations in statics do not get deduplicated

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This commit is contained in:
Oli Scherer 2024-02-26 18:03:06 +00:00
parent 92414ab25d
commit d3514a036d
21 changed files with 259 additions and 54 deletions
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39
compiler/rustc_passes/src/reachable.rs
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@ -13,6 +13,7 @@ use rustc_hir::intravisit::{self, Visitor};
use rustc_hir::Node;
use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
use rustc_middle::middle::privacy::{self, Level};
use rustc_middle::mir::interpret::{ConstAllocation, GlobalAlloc};
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, TyCtxt};
use rustc_session::config::CrateType;
@ -197,10 +198,23 @@ impl<'tcx> ReachableContext<'tcx> {
// Reachable constants will be inlined into other crates
// unconditionally, so we need to make sure that their
// contents are also reachable.
hir::ItemKind::Const(_, _, init) | hir::ItemKind::Static(_, _, init) => {
hir::ItemKind::Const(_, _, init) => {
self.visit_nested_body(init);
}
// Reachable statics are inlined if read from another constant or static
// in other crates. Additionally anonymous nested statics may be created
// when evaluating a static, so preserve those, too.
hir::ItemKind::Static(_, _, init) => {
// FIXME(oli-obk): remove this body walking and instead walk the evaluated initializer
// to find nested items that end up in the final value instead of also marking symbols
// as reachable that are only needed for evaluation.
self.visit_nested_body(init);
if let Ok(alloc) = self.tcx.eval_static_initializer(item.owner_id.def_id) {
self.propagate_statics_from_alloc(item.owner_id.def_id, alloc);
}
}
// These are normal, nothing reachable about these
// inherently and their children are already in the
// worklist, as determined by the privacy pass
@ -266,6 +280,29 @@ impl<'tcx> ReachableContext<'tcx> {
}
}
}
/// Finds anonymous nested statics created for nested allocations and adds them to `reachable_symbols`.
fn propagate_statics_from_alloc(&mut self, root: LocalDefId, alloc: ConstAllocation<'tcx>) {
if !self.any_library {
return;
}
for (_, prov) in alloc.0.provenance().ptrs().iter() {
match self.tcx.global_alloc(prov.alloc_id()) {
GlobalAlloc::Static(def_id) => {
if let Some(def_id) = def_id.as_local()
&& self.tcx.local_parent(def_id) == root
// This is the main purpose of this function: add the def_id we find
// to `reachable_symbols`.
&& self.reachable_symbols.insert(def_id)
&& let Ok(alloc) = self.tcx.eval_static_initializer(def_id)
{
self.propagate_statics_from_alloc(root, alloc);
}
}
GlobalAlloc::Function(_) | GlobalAlloc::VTable(_, _) | GlobalAlloc::Memory(_) => {}
}
}
}
}
fn check_item<'tcx>(