Do partial SsaLocals analysis in unoptimized builds

Author: saethlin

compiler/rustc_mir_transform/src/add_retag.rs

@@ -47,8 +47,8 @@ fn may_contain_reference<'tcx>(ty: Ty<'tcx>, depth: u32, tcx: TyCtxt<'tcx>) -> b
 }
 
 impl<'tcx> crate::MirPass<'tcx> for AddRetag {
-    fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
-        sess.opts.unstable_opts.mir_emit_retag
+    fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
+        tcx.sess.opts.unstable_opts.mir_emit_retag
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

compiler/rustc_mir_transform/src/check_alignment.rs

@@ -4,15 +4,14 @@ use rustc_middle::mir::interpret::Scalar;
 use rustc_middle::mir::visit::PlaceContext;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{Ty, TyCtxt};
-use rustc_session::Session;
 
 use crate::check_pointers::{BorrowedFieldProjectionMode, PointerCheck, check_pointers};
 
 pub(super) struct CheckAlignment;
 
 impl<'tcx> crate::MirPass<'tcx> for CheckAlignment {
-    fn is_enabled(&self, sess: &Session) -> bool {
-        sess.ub_checks()
+    fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
+        tcx.sess.ub_checks()
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

compiler/rustc_mir_transform/src/check_enums.rs

@@ -6,7 +6,6 @@ use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::*;
 use rustc_middle::ty::layout::PrimitiveExt;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypingEnv};
-use rustc_session::Session;
 use tracing::debug;
 
 /// This pass inserts checks for a valid enum discriminant where they are most
@@ -15,8 +14,8 @@ use tracing::debug;
 pub(super) struct CheckEnums;
 
 impl<'tcx> crate::MirPass<'tcx> for CheckEnums {
-    fn is_enabled(&self, sess: &Session) -> bool {
-        sess.ub_checks()
+    fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
+        tcx.sess.ub_checks()
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

compiler/rustc_mir_transform/src/check_null.rs

@@ -2,15 +2,14 @@ use rustc_index::IndexVec;
 use rustc_middle::mir::visit::{MutatingUseContext, NonMutatingUseContext, PlaceContext};
 use rustc_middle::mir::*;
 use rustc_middle::ty::{Ty, TyCtxt};
-use rustc_session::Session;
 
 use crate::check_pointers::{BorrowedFieldProjectionMode, PointerCheck, check_pointers};
 
 pub(super) struct CheckNull;
 
 impl<'tcx> crate::MirPass<'tcx> for CheckNull {
-    fn is_enabled(&self, sess: &Session) -> bool {
-        sess.ub_checks()
+    fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
+        tcx.sess.ub_checks()
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

compiler/rustc_mir_transform/src/copy_prop.rs

@@ -5,7 +5,8 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 use tracing::{debug, instrument};
 
-use crate::ssa::SsaLocals;
+use crate::pass_manager as pm;
+use crate::ssa::{SsaAnalysis, SsaLocals};
 
 /// Unify locals that copy each other.
 ///
@@ -17,21 +18,39 @@ use crate::ssa::SsaLocals;
 /// where each of the locals is only assigned once.
 ///
 /// We want to replace all those locals by `_a`, either copied or moved.
-pub(super) struct CopyProp;
+pub(super) enum CopyProp {
+    Partial,
+    Full,
+}
 
 impl<'tcx> crate::MirPass<'tcx> for CopyProp {
-    fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
-        sess.mir_opt_level() >= 1
+    fn name(&self) -> &'static str {
+        match self {
+            CopyProp::Partial => "CopyProp-partial",
+            CopyProp::Full => "CopyProp",
+        }
+    }
+
+    fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
+        match self {
+            CopyProp::Partial => {
+                tcx.sess.mir_opt_level() == 1
+                    && !pm::should_run_pass(tcx, &CopyProp::Full, pm::Optimizations::Allowed)
+            }
+            CopyProp::Full => tcx.sess.mir_opt_level() >= 2,
+        }
     }
 
     #[instrument(level = "trace", skip(self, tcx, body))]
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         debug!(def_id = ?body.source.def_id());
 
         let typing_env = body.typing_env(tcx);
-        let ssa = SsaLocals::new(tcx, body, typing_env);
-        debug!(borrowed_locals = ?ssa.borrowed_locals());
-        debug!(copy_classes = ?ssa.copy_classes());
+        let ssa_analysis = match self {
+            CopyProp::Partial => SsaAnalysis::Partial,
+            CopyProp::Full => SsaAnalysis::Full,
+        };
+        let ssa = SsaLocals::new(tcx, body, typing_env, ssa_analysis);
 
         let mut any_replacement = false;
         let mut storage_to_remove = DenseBitSet::new_empty(body.local_decls.len());

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -24,8 +24,8 @@ mod unexpand;
 pub(super) struct InstrumentCoverage;
 
 impl<'tcx> crate::MirPass<'tcx> for InstrumentCoverage {
-    fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
-        sess.instrument_coverage()
+    fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
+        tcx.sess.instrument_coverage()
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, mir_body: &mut mir::Body<'tcx>) {

compiler/rustc_mir_transform/src/dataflow_const_prop.rs

@@ -34,8 +34,8 @@ const PLACE_LIMIT: usize = 100;
 pub(super) struct DataflowConstProp;
 
 impl<'tcx> crate::MirPass<'tcx> for DataflowConstProp {
-    fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
-        sess.mir_opt_level() >= 3
+    fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
+        tcx.sess.mir_opt_level() >= 3
     }
 
     #[instrument(skip_all level = "debug")]

compiler/rustc_mir_transform/src/dead_store_elimination.rs

@@ -140,8 +140,8 @@ impl<'tcx> crate::MirPass<'tcx> for DeadStoreElimination {
         }
     }
 
-    fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
-        sess.mir_opt_level() >= 2
+    fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
+        tcx.sess.mir_opt_level() >= 2
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

compiler/rustc_mir_transform/src/dest_prop.rs

@@ -149,7 +149,7 @@ use tracing::{debug, trace};
 pub(super) struct DestinationPropagation;
 
 impl<'tcx> crate::MirPass<'tcx> for DestinationPropagation {
-    fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
+    fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
         // For now, only run at MIR opt level 3. Two things need to be changed before this can be
         // turned on by default:
         //  1. Because of the overeager removal of storage statements, this can cause stack space
@@ -158,7 +158,7 @@ impl<'tcx> crate::MirPass<'tcx> for DestinationPropagation {
         //  2. Despite being an overall perf improvement, this still causes a 30% regression in
         //     keccak. We can temporarily fix this by bounding function size, but in the long term
         //     we should fix this by being smarter about invalidating analysis results.
-        sess.mir_opt_level() >= 3
+        tcx.sess.mir_opt_level() >= 3
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

compiler/rustc_mir_transform/src/early_otherwise_branch.rs

@@ -93,8 +93,8 @@ use crate::patch::MirPatch;
 pub(super) struct EarlyOtherwiseBranch;
 
 impl<'tcx> crate::MirPass<'tcx> for EarlyOtherwiseBranch {
-    fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
-        sess.mir_opt_level() >= 2
+    fn is_enabled(&self, tcx: TyCtxt<'tcx>) -> bool {
+        tcx.sess.mir_opt_level() >= 2
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {