Disable non-required MIR opts with optimize(none)

Co-authored-by: Waffle Lapkin <[email protected]>

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -46,6 +46,12 @@ pub enum OptimizeAttr {
     Size,
 }
 
+impl OptimizeAttr {
+    pub fn do_not_optimize(&self) -> bool {
+        matches!(self, Self::DoNotOptimize)
+    }
+}
+
 #[derive(Clone, Debug, Encodable, Decodable)]
 pub enum DiagnosticAttribute {
     // tidy-alphabetical-start

compiler/rustc_mir_transform/src/abort_unwinding_calls.rs

@@ -116,4 +116,8 @@ impl<'tcx> crate::MirPass<'tcx> for AbortUnwindingCalls {
         // We may have invalidated some `cleanup` blocks so clean those up now.
         super::simplify::remove_dead_blocks(body);
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }

compiler/rustc_mir_transform/src/add_call_guards.rs

@@ -75,4 +75,8 @@ impl<'tcx> crate::MirPass<'tcx> for AddCallGuards {
 
         body.basic_blocks_mut().extend(new_blocks);
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }

compiler/rustc_mir_transform/src/add_moves_for_packed_drops.rs

@@ -68,6 +68,10 @@ impl<'tcx> crate::MirPass<'tcx> for AddMovesForPackedDrops {
 
         patch.apply(body);
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }
 
 fn add_move_for_packed_drop<'tcx>(

compiler/rustc_mir_transform/src/add_retag.rs

@@ -176,4 +176,8 @@ impl<'tcx> crate::MirPass<'tcx> for AddRetag {
             }
         }
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }

compiler/rustc_mir_transform/src/add_subtyping_projections.rs

@@ -61,4 +61,8 @@ impl<'tcx> crate::MirPass<'tcx> for Subtyper {
         }
         checker.patcher.apply(body);
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }

compiler/rustc_mir_transform/src/check_alignment.rs

@@ -60,6 +60,10 @@ impl<'tcx> crate::MirPass<'tcx> for CheckAlignment {
             }
         }
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }
 
 struct PointerFinder<'a, 'tcx> {

compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs

@@ -72,4 +72,8 @@ impl<'tcx> crate::MirPass<'tcx> for CleanupPostBorrowck {
             decl.user_ty = None;
         }
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }

compiler/rustc_mir_transform/src/copy_prop.rs

@@ -56,6 +56,10 @@ impl<'tcx> crate::MirPass<'tcx> for CopyProp {
             crate::simplify::remove_unused_definitions(body);
         }
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 /// `SsaLocals` computed equivalence classes between locals considering copy/move assignments.

compiler/rustc_mir_transform/src/coroutine.rs

@@ -1688,6 +1688,10 @@ impl<'tcx> crate::MirPass<'tcx> for StateTransform {
         // Run derefer to fix Derefs that are not in the first place
         deref_finder(tcx, body);
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }
 
 /// Looks for any assignments between locals (e.g., `_4 = _5`) that will both be converted to fields

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -61,6 +61,10 @@ impl<'tcx> crate::MirPass<'tcx> for InstrumentCoverage {
 
         instrument_function_for_coverage(tcx, mir_body);
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 fn instrument_function_for_coverage<'tcx>(tcx: TyCtxt<'tcx>, mir_body: &mut mir::Body<'tcx>) {

compiler/rustc_mir_transform/src/cross_crate_inline.rs

@@ -69,7 +69,7 @@ fn cross_crate_inlinable(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
     // Don't do any inference if codegen optimizations are disabled and also MIR inlining is not
     // enabled. This ensures that we do inference even if someone only passes -Zinline-mir,
     // which is less confusing than having to also enable -Copt-level=1.
-    let inliner_will_run = pm::should_run_pass(tcx, &inline::Inline)
+    let inliner_will_run = pm::should_run_pass(tcx, &inline::Inline, pm::Optimizations::Allowed)
         || inline::ForceInline::should_run_pass_for_callee(tcx, def_id.to_def_id());
     if matches!(tcx.sess.opts.optimize, OptLevel::No) && !inliner_will_run {
         return false;

compiler/rustc_mir_transform/src/ctfe_limit.rs

@@ -36,6 +36,10 @@ impl<'tcx> crate::MirPass<'tcx> for CtfeLimit {
             );
         }
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }
 
 fn has_back_edge(

compiler/rustc_mir_transform/src/dataflow_const_prop.rs

@@ -71,6 +71,10 @@ impl<'tcx> crate::MirPass<'tcx> for DataflowConstProp {
         let mut patch = visitor.patch;
         debug_span!("patch").in_scope(|| patch.visit_body_preserves_cfg(body));
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 // Note: Currently, places that have their reference taken cannot be tracked. Although this would

compiler/rustc_mir_transform/src/dead_store_elimination.rs

@@ -147,4 +147,8 @@ impl<'tcx> crate::MirPass<'tcx> for DeadStoreElimination {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         eliminate(tcx, body);
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }

compiler/rustc_mir_transform/src/deduplicate_blocks.rs

@@ -31,6 +31,10 @@ impl<'tcx> crate::MirPass<'tcx> for DeduplicateBlocks {
             simplify_cfg(body);
         }
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 struct OptApplier<'tcx> {

compiler/rustc_mir_transform/src/deref_separator.rs

@@ -81,4 +81,8 @@ impl<'tcx> crate::MirPass<'tcx> for Derefer {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         deref_finder(tcx, body);
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }

compiler/rustc_mir_transform/src/dest_prop.rs

@@ -240,6 +240,10 @@ impl<'tcx> crate::MirPass<'tcx> for DestinationPropagation {
 
         trace!(round_count);
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 #[derive(Debug, Default)]

compiler/rustc_mir_transform/src/dump_mir.rs

@@ -15,6 +15,10 @@ impl<'tcx> crate::MirPass<'tcx> for Marker {
     }
 
     fn run_pass(&self, _tcx: TyCtxt<'tcx>, _body: &mut Body<'tcx>) {}
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 pub fn emit_mir(tcx: TyCtxt<'_>) -> io::Result<()> {

compiler/rustc_mir_transform/src/early_otherwise_branch.rs

@@ -227,6 +227,10 @@ impl<'tcx> crate::MirPass<'tcx> for EarlyOtherwiseBranch {
             simplify_cfg(body);
         }
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 #[derive(Debug)]

compiler/rustc_mir_transform/src/elaborate_box_derefs.rs

@@ -150,4 +150,8 @@ impl<'tcx> crate::MirPass<'tcx> for ElaborateBoxDerefs {
             }
         }
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }

compiler/rustc_mir_transform/src/elaborate_drops.rs

@@ -88,6 +88,10 @@ impl<'tcx> crate::MirPass<'tcx> for ElaborateDrops {
         elaborate_patch.apply(body);
         deref_finder(tcx, body);
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }
 
 /// Records unwind edges which are known to be unreachable, because they are in `drop` terminators

compiler/rustc_mir_transform/src/gvn.rs

@@ -163,6 +163,10 @@ impl<'tcx> crate::MirPass<'tcx> for GVN {
         // statements.
         StorageRemover { tcx, reused_locals: state.reused_locals }.visit_body_preserves_cfg(body);
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 newtype_index! {

compiler/rustc_mir_transform/src/impossible_predicates.rs

@@ -53,4 +53,8 @@ impl<'tcx> MirPass<'tcx> for ImpossiblePredicates {
             body.local_decls.raw.truncate(body.arg_count + 1);
         }
     }
+
+    fn is_required(&self) -> bool {
+        true
+    }
 }

compiler/rustc_mir_transform/src/inline.rs

@@ -66,6 +66,10 @@ impl<'tcx> crate::MirPass<'tcx> for Inline {
             deref_finder(tcx, body);
         }
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 pub struct ForceInline;
@@ -85,6 +89,10 @@ impl<'tcx> crate::MirPass<'tcx> for ForceInline {
         false
     }
 
+    fn is_required(&self) -> bool {
+        true
+    }
+
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         let span = trace_span!("force_inline", body = %tcx.def_path_str(body.source.def_id()));
         let _guard = span.enter();

compiler/rustc_mir_transform/src/instsimplify.rs

@@ -62,6 +62,10 @@ impl<'tcx> crate::MirPass<'tcx> for InstSimplify {
             simplify_duplicate_switch_targets(block.terminator.as_mut().unwrap());
         }
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 struct InstSimplifyContext<'a, 'tcx> {

compiler/rustc_mir_transform/src/jump_threading.rs

@@ -105,6 +105,10 @@ impl<'tcx> crate::MirPass<'tcx> for JumpThreading {
         }
         OpportunitySet::new(body, opportunities).apply(body);
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 #[derive(Debug)]

compiler/rustc_mir_transform/src/large_enums.rs

@@ -200,6 +200,10 @@ impl<'tcx> crate::MirPass<'tcx> for EnumSizeOpt {
             });
         }
     }
+
+    fn is_required(&self) -> bool {
+        false
+    }
 }
 
 impl EnumSizeOpt {

compiler/rustc_mir_transform/src/lib.rs

@@ -388,6 +388,7 @@ fn mir_built(tcx: TyCtxt<'_>, def: LocalDefId) -> &Steal<Body<'_>> {
             &Lint(sanity_check::SanityCheck),
         ],
         None,
+        pm::Optimizations::Allowed,
     );
     tcx.alloc_steal_mir(body)
 }
@@ -440,6 +441,7 @@ fn mir_promoted(
         &mut body,
         &[&promote_pass, &simplify::SimplifyCfg::PromoteConsts, &coverage::InstrumentCoverage],
         Some(MirPhase::Analysis(AnalysisPhase::Initial)),
+        pm::Optimizations::Allowed,
     );
 
     lint_tail_expr_drop_order::run_lint(tcx, def, &body);
@@ -473,7 +475,7 @@ fn inner_mir_for_ctfe(tcx: TyCtxt<'_>, def: LocalDefId) -> Body<'_> {
     };
 
     let mut body = remap_mir_for_const_eval_select(tcx, body, hir::Constness::Const);
-    pm::run_passes(tcx, &mut body, &[&ctfe_limit::CtfeLimit], None);
+    pm::run_passes(tcx, &mut body, &[&ctfe_limit::CtfeLimit], None, pm::Optimizations::Allowed);
 
     body
 }
@@ -493,7 +495,7 @@ fn mir_drops_elaborated_and_const_checked(tcx: TyCtxt<'_>, def: LocalDefId) -> &
     let is_fn_like = tcx.def_kind(def).is_fn_like();
     if is_fn_like {
         // Do not compute the mir call graph without said call graph actually being used.
-        if pm::should_run_pass(tcx, &inline::Inline)
+        if pm::should_run_pass(tcx, &inline::Inline, pm::Optimizations::Allowed)
             || inline::ForceInline::should_run_pass_for_callee(tcx, def.to_def_id())
         {
             tcx.ensure_with_value().mir_inliner_callees(ty::InstanceKind::Item(def.to_def_id()));
@@ -533,6 +535,7 @@ pub fn run_analysis_to_runtime_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'
                 &Lint(post_drop_elaboration::CheckLiveDrops),
             ],
             None,
+            pm::Optimizations::Allowed,
         );
     }
 
@@ -557,7 +560,13 @@ fn run_analysis_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         &deref_separator::Derefer,
     ];
 
-    pm::run_passes(tcx, body, passes, Some(MirPhase::Analysis(AnalysisPhase::PostCleanup)));
+    pm::run_passes(
+        tcx,
+        body,
+        passes,
+        Some(MirPhase::Analysis(AnalysisPhase::PostCleanup)),
+        pm::Optimizations::Allowed,
+    );
 }
 
 /// Returns the sequence of passes that lowers analysis to runtime MIR.
@@ -597,7 +606,13 @@ fn run_runtime_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         &simplify::SimplifyCfg::PreOptimizations,
     ];
 
-    pm::run_passes(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::PostCleanup)));
+    pm::run_passes(
+        tcx,
+        body,
+        passes,
+        Some(MirPhase::Runtime(RuntimePhase::PostCleanup)),
+        pm::Optimizations::Allowed,
+    );
 
     // Clear this by anticipation. Optimizations and runtime MIR have no reason to look
     // into this information, which is meant for borrowck diagnostics.
@@ -611,6 +626,15 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         WithMinOptLevel(1, x)
     }
 
+    let def_id = body.source.def_id();
+    let optimizations = if tcx.def_kind(def_id).has_codegen_attrs()
+        && tcx.codegen_fn_attrs(def_id).optimize.do_not_optimize()
+    {
+        pm::Optimizations::Suppressed
+    } else {
+        pm::Optimizations::Allowed
+    };
+
     // The main optimizations that we do on MIR.
     pm::run_passes(
         tcx,
@@ -683,6 +707,7 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
             &dump_mir::Marker("PreCodegen"),
         ],
         Some(MirPhase::Runtime(RuntimePhase::Optimized)),
+        optimizations,
     );
 }