Rollup merge of #100919 - sanxiyn:parallel-liveness, r=oli-obk

Use par_body_owners for liveness

I did this refactoring while working on something else. Liveness is about bodies, there is no reason to use par_for_each_module here.

Tests are updated because things are visited in a different order. I checked diagnostics are same, just in a different (and IMO, better) order.

Author: matthiaskrgr

compiler/rustc_interface/src/passes.rs

@@ -911,13 +911,13 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) -> Result<()> {
                 });
             },
             {
-                sess.time("liveness_and_intrinsic_checking", || {
-                    tcx.hir().par_for_each_module(|module| {
+                sess.time("liveness_checking", || {
+                    tcx.hir().par_body_owners(|def_id| {
                         // this must run before MIR dump, because
                         // "not all control paths return a value" is reported here.
                         //
                         // maybe move the check to a MIR pass?
-                        tcx.ensure().check_mod_liveness(module);
+                        tcx.ensure().check_liveness(def_id.to_def_id());
                     });
                 });
             }

compiler/rustc_middle/src/query/mod.rs

@@ -818,8 +818,8 @@ rustc_queries! {
         desc { |tcx| "checking privacy in {}", describe_as_module(key, tcx) }
     }
 
-    query check_mod_liveness(key: LocalDefId) -> () {
-        desc { |tcx| "checking liveness of variables in {}", describe_as_module(key, tcx) }
+    query check_liveness(key: DefId) {
+        desc { |tcx| "checking liveness of variables in {}", tcx.def_path_str(key) }
     }
 
     /// Return the live symbols in the crate for dead code check.

compiler/rustc_passes/src/liveness.rs

@@ -89,11 +89,10 @@ use rustc_data_structures::fx::FxIndexMap;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::def::*;
-use rustc_hir::def_id::LocalDefId;
+use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{Expr, HirId, HirIdMap, HirIdSet};
 use rustc_index::vec::IndexVec;
-use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, DefIdTree, RootVariableMinCaptureList, Ty, TyCtxt};
 use rustc_session::lint;
@@ -139,12 +138,54 @@ fn live_node_kind_to_string(lnk: LiveNodeKind, tcx: TyCtxt<'_>) -> String {
     }
 }
 
-fn check_mod_liveness(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
-    tcx.hir().visit_item_likes_in_module(module_def_id, &mut IrMaps::new(tcx));
+fn check_liveness(tcx: TyCtxt<'_>, def_id: DefId) {
+    let local_def_id = match def_id.as_local() {
+        None => return,
+        Some(def_id) => def_id,
+    };
+
+    // Don't run unused pass for #[derive()]
+    let parent = tcx.local_parent(local_def_id);
+    if let DefKind::Impl = tcx.def_kind(parent)
+        && tcx.has_attr(parent.to_def_id(), sym::automatically_derived)
+    {
+        return;
+    }
+
+    // Don't run unused pass for #[naked]
+    if tcx.has_attr(def_id, sym::naked) {
+        return;
+    }
+
+    let mut maps = IrMaps::new(tcx);
+    let body_id = tcx.hir().body_owned_by(local_def_id);
+    let hir_id = tcx.hir().body_owner(body_id);
+    let body = tcx.hir().body(body_id);
+
+    if let Some(upvars) = tcx.upvars_mentioned(def_id) {
+        for &var_hir_id in upvars.keys() {
+            let var_name = tcx.hir().name(var_hir_id);
+            maps.add_variable(Upvar(var_hir_id, var_name));
+        }
+    }
+
+    // gather up the various local variables, significant expressions,
+    // and so forth:
+    maps.visit_body(body);
+
+    // compute liveness
+    let mut lsets = Liveness::new(&mut maps, local_def_id);
+    let entry_ln = lsets.compute(&body, hir_id);
+    lsets.log_liveness(entry_ln, body_id.hir_id);
+
+    // check for various error conditions
+    lsets.visit_body(body);
+    lsets.warn_about_unused_upvars(entry_ln);
+    lsets.warn_about_unused_args(body, entry_ln);
 }
 
 pub fn provide(providers: &mut Providers) {
-    *providers = Providers { check_mod_liveness, ..*providers };
+    *providers = Providers { check_liveness, ..*providers };
 }
 
 // ______________________________________________________________________
@@ -316,56 +357,6 @@ impl<'tcx> IrMaps<'tcx> {
 }
 
 impl<'tcx> Visitor<'tcx> for IrMaps<'tcx> {
-    type NestedFilter = nested_filter::OnlyBodies;
-
-    fn nested_visit_map(&mut self) -> Self::Map {
-        self.tcx.hir()
-    }
-
-    fn visit_body(&mut self, body: &'tcx hir::Body<'tcx>) {
-        debug!("visit_body {:?}", body.id());
-
-        // swap in a new set of IR maps for this body
-        let mut maps = IrMaps::new(self.tcx);
-        let hir_id = maps.tcx.hir().body_owner(body.id());
-        let local_def_id = maps.tcx.hir().local_def_id(hir_id);
-        let def_id = local_def_id.to_def_id();
-
-        // Don't run unused pass for #[derive()]
-        let parent = self.tcx.local_parent(local_def_id);
-        if let DefKind::Impl = self.tcx.def_kind(parent)
-            && self.tcx.has_attr(parent.to_def_id(), sym::automatically_derived)
-        {
-            return;
-        }
-
-        // Don't run unused pass for #[naked]
-        if self.tcx.has_attr(def_id, sym::naked) {
-            return;
-        }
-
-        if let Some(upvars) = maps.tcx.upvars_mentioned(def_id) {
-            for &var_hir_id in upvars.keys() {
-                let var_name = maps.tcx.hir().name(var_hir_id);
-                maps.add_variable(Upvar(var_hir_id, var_name));
-            }
-        }
-
-        // gather up the various local variables, significant expressions,
-        // and so forth:
-        intravisit::walk_body(&mut maps, body);
-
-        // compute liveness
-        let mut lsets = Liveness::new(&mut maps, local_def_id);
-        let entry_ln = lsets.compute(&body, hir_id);
-        lsets.log_liveness(entry_ln, body.id().hir_id);
-
-        // check for various error conditions
-        lsets.visit_body(body);
-        lsets.warn_about_unused_upvars(entry_ln);
-        lsets.warn_about_unused_args(body, entry_ln);
-    }
-
     fn visit_local(&mut self, local: &'tcx hir::Local<'tcx>) {
         self.add_from_pat(&local.pat);
         if local.els.is_some() {

src/test/ui/closures/2229_closure_analysis/run_pass/destructure-pattern-closure-within-closure.stderr

@@ -1,8 +1,8 @@
-warning: unused variable: `t2`
-  --> $DIR/destructure-pattern-closure-within-closure.rs:13:21
+warning: unused variable: `g2`
+  --> $DIR/destructure-pattern-closure-within-closure.rs:10:17
    |
-LL |             let (_, t2) = t;
-   |                     ^^ help: if this is intentional, prefix it with an underscore: `_t2`
+LL |         let (_, g2) = g;
+   |                 ^^ help: if this is intentional, prefix it with an underscore: `_g2`
    |
 note: the lint level is defined here
   --> $DIR/destructure-pattern-closure-within-closure.rs:3:9
@@ -11,11 +11,11 @@ LL | #![warn(unused)]
    |         ^^^^^^
    = note: `#[warn(unused_variables)]` implied by `#[warn(unused)]`
 
-warning: unused variable: `g2`
-  --> $DIR/destructure-pattern-closure-within-closure.rs:10:17
+warning: unused variable: `t2`
+  --> $DIR/destructure-pattern-closure-within-closure.rs:13:21
    |
-LL |         let (_, g2) = g;
-   |                 ^^ help: if this is intentional, prefix it with an underscore: `_g2`
+LL |             let (_, t2) = t;
+   |                     ^^ help: if this is intentional, prefix it with an underscore: `_t2`
 
 warning: 2 warnings emitted
 

src/test/ui/lint/unused/issue-54180-unused-ref-field.stderr

@@ -11,12 +11,6 @@ LL | #![deny(unused)]
    |         ^^^^^^
    = note: `#[deny(unused_variables)]` implied by `#[deny(unused)]`
 
-error: unused variable: `x`
-  --> $DIR/issue-54180-unused-ref-field.rs:29:45
-   |
-LL |     let _: i32 = points.iter().map(|Point { x, y }| y).sum();
-   |                                             ^ help: try ignoring the field: `x: _`
-
 error: unused variable: `f1`
   --> $DIR/issue-54180-unused-ref-field.rs:26:13
    |
@@ -29,5 +23,11 @@ error: unused variable: `x`
 LL |         Point { y, ref mut x } => y,
    |                    ^^^^^^^^^ help: try ignoring the field: `x: _`
 
+error: unused variable: `x`
+  --> $DIR/issue-54180-unused-ref-field.rs:29:45
+   |
+LL |     let _: i32 = points.iter().map(|Point { x, y }| y).sum();
+   |                                             ^ help: try ignoring the field: `x: _`
+
 error: aborting due to 4 previous errors
 

src/test/ui/lint/unused/lint-unused-variables.stderr

@@ -17,55 +17,55 @@ LL |     b: i32,
    |     ^ help: if this is intentional, prefix it with an underscore: `_b`
 
 error: unused variable: `a`
-  --> $DIR/lint-unused-variables.rs:68:9
+  --> $DIR/lint-unused-variables.rs:22:9
    |
 LL |         a: i32,
    |         ^ help: if this is intentional, prefix it with an underscore: `_a`
 
 error: unused variable: `b`
-  --> $DIR/lint-unused-variables.rs:74:9
+  --> $DIR/lint-unused-variables.rs:29:9
    |
 LL |         b: i32,
    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
 
 error: unused variable: `b`
-  --> $DIR/lint-unused-variables.rs:42:9
+  --> $DIR/lint-unused-variables.rs:34:9
    |
 LL |         b: i32,
    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
 
 error: unused variable: `b`
-  --> $DIR/lint-unused-variables.rs:47:9
+  --> $DIR/lint-unused-variables.rs:42:9
    |
 LL |         b: i32,
    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
 
-error: unused variable: `a`
-  --> $DIR/lint-unused-variables.rs:22:9
-   |
-LL |         a: i32,
-   |         ^ help: if this is intentional, prefix it with an underscore: `_a`
-
 error: unused variable: `b`
-  --> $DIR/lint-unused-variables.rs:29:9
+  --> $DIR/lint-unused-variables.rs:47:9
    |
 LL |         b: i32,
    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
 
 error: unused variable: `b`
-  --> $DIR/lint-unused-variables.rs:34:9
+  --> $DIR/lint-unused-variables.rs:55:9
    |
 LL |         b: i32,
    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
 
 error: unused variable: `b`
-  --> $DIR/lint-unused-variables.rs:55:9
+  --> $DIR/lint-unused-variables.rs:60:9
    |
 LL |         b: i32,
    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
 
+error: unused variable: `a`
+  --> $DIR/lint-unused-variables.rs:68:9
+   |
+LL |         a: i32,
+   |         ^ help: if this is intentional, prefix it with an underscore: `_a`
+
 error: unused variable: `b`
-  --> $DIR/lint-unused-variables.rs:60:9
+  --> $DIR/lint-unused-variables.rs:74:9
    |
 LL |         b: i32,
    |         ^ help: if this is intentional, prefix it with an underscore: `_b`

src/test/ui/liveness/liveness-consts.stderr

@@ -39,12 +39,6 @@ warning: unused variable: `z`
 LL | pub fn f(x: [u8; { let s = 17; 100 }]) -> [u8;  { let z = 18; 100 }] {
    |                                                       ^ help: if this is intentional, prefix it with an underscore: `_z`
 
-warning: unused variable: `z`
-  --> $DIR/liveness-consts.rs:60:13
-   |
-LL |         let z = 42;
-   |             ^ help: if this is intentional, prefix it with an underscore: `_z`
-
 warning: value assigned to `t` is never read
   --> $DIR/liveness-consts.rs:42:9
    |
@@ -59,5 +53,11 @@ warning: unused variable: `w`
 LL |         let w = 10;
    |             ^ help: if this is intentional, prefix it with an underscore: `_w`
 
+warning: unused variable: `z`
+  --> $DIR/liveness-consts.rs:60:13
+   |
+LL |         let z = 42;
+   |             ^ help: if this is intentional, prefix it with an underscore: `_z`
+
 warning: 8 warnings emitted