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Auto merge of #106227 - bryangarza:ctfe-limit, r=oli-obk

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Use stable metric for const eval limit instead of current terminator-based logic

This patch adds a `MirPass` that inserts a new MIR instruction `ConstEvalCounter` to any loops and function calls in the CFG. This instruction is used during Const Eval to count against the `const_eval_limit`, and emit the `StepLimitReached` error, replacing the current logic which uses Terminators only.

The new method of counting loops and function calls should be more stable across compiler versions (i.e., not cause crates that compiled successfully before, to no longer compile when changes to the MIR generation/optimization are made).

Also see: #103877
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bors 2023-01-29 04:11:27 +00:00
commit 3cdd0197e7
50 changed files with 400 additions and 20 deletions
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3
compiler/rustc_mir_transform/src/lib.rs
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@ -55,6 +55,7 @@ mod const_goto;
mod const_prop;
mod const_prop_lint;
mod coverage;
mod ctfe_limit;
mod dataflow_const_prop;
mod dead_store_elimination;
mod deaggregator;
@ -410,6 +411,8 @@ fn inner_mir_for_ctfe(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -
}
}
pm::run_passes(tcx, &mut body, &[&ctfe_limit::CtfeLimit], None);
debug_assert!(!body.has_free_regions(), "Free regions in MIR for CTFE");
body