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Use DefPathHash instead of HirId to break cycles.

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This commit is contained in:
Camille GILLOT 2021-05-13 09:28:56 +02:00
parent 0677edc86e
commit e1b36f5ae2
1 changed files with 8 additions and 14 deletions
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22
compiler/rustc_mir_transform/src/inline.rs
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@ -1,7 +1,6 @@
//! Inlining pass for MIR functions
use rustc_attr::InlineAttr;
use rustc_hir as hir;
use rustc_index::bit_set::BitSet;
use rustc_index::vec::Idx;
use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
@ -88,7 +87,6 @@ fn inline<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) -> bool {
tcx,
param_env,
codegen_fn_attrs: tcx.codegen_fn_attrs(def_id),
hir_id,
history: Vec::new(),
changed: false,
};
@ -102,8 +100,6 @@ struct Inliner<'tcx> {
param_env: ParamEnv<'tcx>,
/// Caller codegen attributes.
codegen_fn_attrs: &'tcx CodegenFnAttrs,
/// Caller HirID.
hir_id: hir::HirId,
/// Stack of inlined Instances.
history: Vec<ty::Instance<'tcx>>,
/// Indicates that the caller body has been modified.
@ -179,7 +175,8 @@ impl<'tcx> Inliner<'tcx> {
caller_body: &Body<'tcx>,
callee: &Instance<'tcx>,
) -> Result<(), &'static str> {
if callee.def_id() == caller_body.source.def_id() {
let caller_def_id = caller_body.source.def_id();
if callee.def_id() == caller_def_id {
return Err("self-recursion");
}
@ -215,22 +212,19 @@ impl<'tcx> Inliner<'tcx> {
}
if let Some(callee_def_id) = callee.def_id().as_local() {
let callee_hir_id = self.tcx.hir().local_def_id_to_hir_id(callee_def_id);
// Avoid a cycle here by only using `instance_mir` only if we have
// a lower `HirId` than the callee. This ensures that the callee will
// not inline us. This trick only works without incremental compilation.
// So don't do it if that is enabled.
if !self.tcx.dep_graph.is_fully_enabled() && self.hir_id.index() < callee_hir_id.index()
// a lower `DefPathHash` than the callee. This ensures that the callee will
// not inline us. This trick even works with incremental compilation,
// since `DefPathHash` is stable.
if self.tcx.def_path_hash(caller_def_id)
< self.tcx.def_path_hash(callee_def_id.to_def_id())
{
return Ok(());
}
// If we know for sure that the function we're calling will itself try to
// call us, then we avoid inlining that function.
if self
.tcx
.mir_callgraph_reachable((*callee, caller_body.source.def_id().expect_local()))
{
if self.tcx.mir_callgraph_reachable((*callee, caller_def_id.expect_local())) {
return Err("caller might be reachable from callee (query cycle avoidance)");
}