Auto merge of #136000 - matthiaskrgr:rollup-j6ge32r, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #135873 (coverage: Prepare for upcoming changes to counter creation)
 - #135926 (Implement `needs-subprocess` directive, and cleanup a bunch of tests to use `needs-{subprocess,threads}`)
 - #135950 (Tidy Python improvements)
 - #135956 (Make `Vec::pop_if` a bit more presentable)
 - #135966 ([AIX] Allow different sized load and store in `tests/assembly/powerpc64-struct-abi.rs`)
 - #135983 (Doc difference between extend and extend_from_slice)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/covfun.rs

@@ -51,7 +51,7 @@ pub(crate) fn prepare_covfun_record<'tcx>(
     is_used: bool,
 ) -> Option<CovfunRecord<'tcx>> {
     let fn_cov_info = tcx.instance_mir(instance.def).function_coverage_info.as_deref()?;
-    let ids_info = tcx.coverage_ids_info(instance.def);
+    let ids_info = tcx.coverage_ids_info(instance.def)?;
 
     let expressions = prepare_expressions(fn_cov_info, ids_info, is_used);
 

compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs

@@ -8,7 +8,6 @@ use rustc_codegen_ssa::traits::{
 use rustc_data_structures::fx::{FxHashMap, FxIndexSet};
 use rustc_middle::mir::coverage::CoverageKind;
 use rustc_middle::ty::Instance;
-use rustc_middle::ty::layout::HasTyCtxt;
 use tracing::{debug, instrument};
 
 use crate::builder::Builder;
@@ -147,6 +146,10 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
             debug!("function has a coverage statement but no coverage info");
             return;
         };
+        let Some(ids_info) = bx.tcx.coverage_ids_info(instance.def) else {
+            debug!("function has a coverage statement but no IDs info");
+            return;
+        };
 
         // Mark the instance as used in this CGU, for coverage purposes.
         // This includes functions that were not partitioned into this CGU,
@@ -162,8 +165,7 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
                 // be smaller than the number originally inserted by the instrumentor,
                 // if some high-numbered counters were removed by MIR optimizations.
                 // If so, LLVM's profiler runtime will use fewer physical counters.
-                let num_counters =
+                let num_counters = ids_info.num_counters_after_mir_opts();
-                    bx.tcx().coverage_ids_info(instance.def).num_counters_after_mir_opts();
                 assert!(
                     num_counters as usize <= function_coverage_info.num_counters,
                     "num_counters disagreement: query says {num_counters} but function info only has {}",

compiler/rustc_middle/src/mir/coverage.rs

@@ -4,7 +4,7 @@ use std::fmt::{self, Debug, Formatter};
 
 use rustc_index::IndexVec;
 use rustc_index::bit_set::DenseBitSet;
-use rustc_macros::{HashStable, TyDecodable, TyEncodable, TypeFoldable, TypeVisitable};
+use rustc_macros::{HashStable, TyDecodable, TyEncodable};
 use rustc_span::Span;
 
 rustc_index::newtype_index! {
@@ -72,7 +72,7 @@ impl ConditionId {
 /// Enum that can hold a constant zero value, the ID of an physical coverage
 /// counter, or the ID of a coverage-counter expression.
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
-#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, Hash, HashStable)]
 pub enum CovTerm {
     Zero,
     Counter(CounterId),
@@ -89,7 +89,7 @@ impl Debug for CovTerm {
     }
 }
 
-#[derive(Clone, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(Clone, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)]
 pub enum CoverageKind {
     /// Marks a span that might otherwise not be represented in MIR, so that
     /// coverage instrumentation can associate it with its enclosing block/BCB.
@@ -151,7 +151,7 @@ impl Debug for CoverageKind {
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable)]
-#[derive(TyEncodable, TyDecodable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable)]
 pub enum Op {
     Subtract,
     Add,
@@ -168,7 +168,7 @@ impl Op {
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
-#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, Hash, HashStable)]
 pub struct Expression {
     pub lhs: CovTerm,
     pub op: Op,
@@ -176,7 +176,7 @@ pub struct Expression {
 }
 
 #[derive(Clone, Debug)]
-#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, Hash, HashStable)]
 pub enum MappingKind {
     /// Associates a normal region of code with a counter/expression/zero.
     Code(CovTerm),
@@ -208,7 +208,7 @@ impl MappingKind {
 }
 
 #[derive(Clone, Debug)]
-#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, Hash, HashStable)]
 pub struct Mapping {
     pub kind: MappingKind,
     pub span: Span,
@@ -218,7 +218,7 @@ pub struct Mapping {
 /// to be used in conjunction with the individual coverage statements injected
 /// into the function's basic blocks.
 #[derive(Clone, Debug)]
-#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, Hash, HashStable)]
 pub struct FunctionCoverageInfo {
     pub function_source_hash: u64,
     pub body_span: Span,
@@ -238,7 +238,7 @@ pub struct FunctionCoverageInfo {
 /// ("Hi" indicates that this is "high-level" information collected at the
 /// THIR/MIR boundary, before the MIR-based coverage instrumentation pass.)
 #[derive(Clone, Debug)]
-#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, Hash, HashStable)]
 pub struct CoverageInfoHi {
     /// 1 more than the highest-numbered [`CoverageKind::BlockMarker`] that was
     /// injected into the MIR body. This makes it possible to allocate per-ID
@@ -252,7 +252,7 @@ pub struct CoverageInfoHi {
 }
 
 #[derive(Clone, Debug)]
-#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, Hash, HashStable)]
 pub struct BranchSpan {
     pub span: Span,
     pub true_marker: BlockMarkerId,
@@ -260,7 +260,7 @@ pub struct BranchSpan {
 }
 
 #[derive(Copy, Clone, Debug)]
-#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, Hash, HashStable)]
 pub struct ConditionInfo {
     pub condition_id: ConditionId,
     pub true_next_id: Option<ConditionId>,
@@ -268,7 +268,7 @@ pub struct ConditionInfo {
 }
 
 #[derive(Clone, Debug)]
-#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, Hash, HashStable)]
 pub struct MCDCBranchSpan {
     pub span: Span,
     pub condition_info: ConditionInfo,
@@ -277,14 +277,14 @@ pub struct MCDCBranchSpan {
 }
 
 #[derive(Copy, Clone, Debug)]
-#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, Hash, HashStable)]
 pub struct DecisionInfo {
     pub bitmap_idx: u32,
     pub num_conditions: u16,
 }
 
 #[derive(Clone, Debug)]
-#[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(TyEncodable, TyDecodable, Hash, HashStable)]
 pub struct MCDCDecisionSpan {
     pub span: Span,
     pub end_markers: Vec<BlockMarkerId>,

compiler/rustc_middle/src/mir/mod.rs

@@ -358,6 +358,8 @@ pub struct Body<'tcx> {
     ///
     /// Only present if coverage is enabled and this function is eligible.
     /// Boxed to limit space overhead in non-coverage builds.
+    #[type_foldable(identity)]
+    #[type_visitable(ignore)]
     pub coverage_info_hi: Option<Box<coverage::CoverageInfoHi>>,
 
     /// Per-function coverage information added by the `InstrumentCoverage`
@@ -366,6 +368,8 @@ pub struct Body<'tcx> {
     ///
     /// If `-Cinstrument-coverage` is not active, or if an individual function
     /// is not eligible for coverage, then this should always be `None`.
+    #[type_foldable(identity)]
+    #[type_visitable(ignore)]
     pub function_coverage_info: Option<Box<coverage::FunctionCoverageInfo>>,
 }
 

compiler/rustc_middle/src/mir/syntax.rs

@@ -417,7 +417,14 @@ pub enum StatementKind<'tcx> {
     ///
     /// Interpreters and codegen backends that don't support coverage instrumentation
     /// can usually treat this as a no-op.
-    Coverage(CoverageKind),
+    Coverage(
+        // Coverage statements are unlikely to ever contain type information in
+        // the foreseeable future, so excluding them from TypeFoldable/TypeVisitable
+        // avoids some unhelpful derive boilerplate.
+        #[type_foldable(identity)]
+        #[type_visitable(ignore)]
+        CoverageKind,
+    ),
 
     /// Denotes a call to an intrinsic that does not require an unwind path and always returns.
     /// This avoids adding a new block and a terminator for simple intrinsics.

compiler/rustc_middle/src/query/mod.rs

@@ -618,7 +618,9 @@ rustc_queries! {
     /// Summarizes coverage IDs inserted by the `InstrumentCoverage` MIR pass
     /// (for compiler option `-Cinstrument-coverage`), after MIR optimizations
     /// have had a chance to potentially remove some of them.
-    query coverage_ids_info(key: ty::InstanceKind<'tcx>) -> &'tcx mir::coverage::CoverageIdsInfo {
+    ///
+    /// Returns `None` for functions that were not instrumented.
+    query coverage_ids_info(key: ty::InstanceKind<'tcx>) -> Option<&'tcx mir::coverage::CoverageIdsInfo> {
         desc { |tcx| "retrieving coverage IDs info from MIR for `{}`", tcx.def_path_str(key.def_id()) }
         arena_cache
     }

compiler/rustc_mir_transform/src/coverage/counters.rs

@@ -11,7 +11,9 @@ use rustc_middle::mir::coverage::{CounterId, CovTerm, Expression, ExpressionId,
 
 use crate::coverage::counters::balanced_flow::BalancedFlowGraph;
 use crate::coverage::counters::iter_nodes::IterNodes;
-use crate::coverage::counters::node_flow::{CounterTerm, MergedNodeFlowGraph, NodeCounters};
+use crate::coverage::counters::node_flow::{
+    CounterTerm, NodeCounters, make_node_counters, node_flow_data_for_balanced_graph,
+};
 use crate::coverage::graph::{BasicCoverageBlock, CoverageGraph};
 
 mod balanced_flow;
@@ -27,12 +29,12 @@ pub(super) fn make_bcb_counters(
 ) -> CoverageCounters {
     // Create the derived graphs that are necessary for subsequent steps.
     let balanced_graph = BalancedFlowGraph::for_graph(graph, |n| !graph[n].is_out_summable);
-    let merged_graph = MergedNodeFlowGraph::for_balanced_graph(&balanced_graph);
+    let node_flow_data = node_flow_data_for_balanced_graph(&balanced_graph);
 
     // Use those graphs to determine which nodes get physical counters, and how
     // to compute the execution counts of other nodes from those counters.
-    let nodes = make_node_counter_priority_list(graph, balanced_graph);
+    let priority_list = make_node_flow_priority_list(graph, balanced_graph);
-    let node_counters = merged_graph.make_node_counters(&nodes);
+    let node_counters = make_node_counters(&node_flow_data, &priority_list);
 
     // Convert the counters into a form suitable for embedding into MIR.
     transcribe_counters(&node_counters, bcb_needs_counter)
@@ -40,7 +42,7 @@ pub(super) fn make_bcb_counters(
 
 /// Arranges the nodes in `balanced_graph` into a list, such that earlier nodes
 /// take priority in being given a counter expression instead of a physical counter.
-fn make_node_counter_priority_list(
+fn make_node_flow_priority_list(
     graph: &CoverageGraph,
     balanced_graph: BalancedFlowGraph<&CoverageGraph>,
 ) -> Vec<BasicCoverageBlock> {
@@ -81,11 +83,11 @@ fn transcribe_counters(
     let mut new = CoverageCounters::with_num_bcbs(bcb_needs_counter.domain_size());
 
     for bcb in bcb_needs_counter.iter() {
-        // Our counter-creation algorithm doesn't guarantee that a counter
+        // Our counter-creation algorithm doesn't guarantee that a node's list
-        // expression starts or ends with a positive term, so partition the
+        // of terms starts or ends with a positive term, so partition the
         // counters into "positive" and "negative" lists for easier handling.
         let (mut pos, mut neg): (Vec<_>, Vec<_>) =
-            old.counter_expr(bcb).iter().partition_map(|&CounterTerm { node, op }| match op {
+            old.counter_terms[bcb].iter().partition_map(|&CounterTerm { node, op }| match op {
                 Op::Add => Either::Left(node),
                 Op::Subtract => Either::Right(node),
             });

compiler/rustc_mir_transform/src/coverage/counters/node_flow.rs

@@ -8,18 +8,17 @@
 
 use rustc_data_structures::graph;
 use rustc_index::bit_set::DenseBitSet;
-use rustc_index::{Idx, IndexVec};
+use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_middle::mir::coverage::Op;
-use smallvec::SmallVec;
 
 use crate::coverage::counters::iter_nodes::IterNodes;
-use crate::coverage::counters::union_find::{FrozenUnionFind, UnionFind};
+use crate::coverage::counters::union_find::UnionFind;
 
 #[cfg(test)]
 mod tests;
 
-/// View of some underlying graph, in which each node's successors have been
+/// Data representing a view of some underlying graph, in which each node's
-/// merged into a single "supernode".
+/// successors have been merged into a single "supernode".
 ///
 /// The resulting supernodes have no obvious meaning on their own.
 /// However, merging successor nodes means that a node's out-edges can all
@@ -30,10 +29,10 @@ mod tests;
 /// in the merged graph, it becomes possible to analyze the original node flows
 /// using techniques for analyzing edge flows.
 #[derive(Debug)]
-pub(crate) struct MergedNodeFlowGraph<Node: Idx> {
+pub(crate) struct NodeFlowData<Node: Idx> {
     /// Maps each node to the supernode that contains it, indicated by some
     /// arbitrary "root" node that is part of that supernode.
-    supernodes: FrozenUnionFind<Node>,
+    supernodes: IndexVec<Node, Node>,
     /// For each node, stores the single supernode that all of its successors
     /// have been merged into.
     ///
@@ -42,17 +41,16 @@ pub(crate) struct MergedNodeFlowGraph<Node: Idx> {
     succ_supernodes: IndexVec<Node, Node>,
 }
 
-impl<Node: Idx> MergedNodeFlowGraph<Node> {
+/// Creates a "merged" view of an underlying graph.
-    /// Creates a "merged" view of an underlying graph.
+///
-    ///
+/// The given graph is assumed to have [“balanced flow”](balanced-flow),
-    /// The given graph is assumed to have [“balanced flow”](balanced-flow),
+/// though it does not necessarily have to be a `BalancedFlowGraph`.
-    /// though it does not necessarily have to be a `BalancedFlowGraph`.
+///
-    ///
+/// [balanced-flow]: `crate::coverage::counters::balanced_flow::BalancedFlowGraph`.
-    /// [balanced-flow]: `crate::coverage::counters::balanced_flow::BalancedFlowGraph`.
+pub(crate) fn node_flow_data_for_balanced_graph<G>(graph: G) -> NodeFlowData<G::Node>
-    pub(crate) fn for_balanced_graph<G>(graph: G) -> Self
+where
-    where
+    G: graph::Successors,
-        G: graph::DirectedGraph<Node = Node> + graph::Successors,
+{
-    {
     let mut supernodes = UnionFind::<G::Node>::new(graph.num_nodes());
 
     // For each node, merge its successors into a single supernode, and
@@ -67,59 +65,47 @@ impl<Node: Idx> MergedNodeFlowGraph<Node> {
         })
         .collect::<IndexVec<G::Node, G::Node>>();
 
-        // Now that unification is complete, freeze the supernode forest,
+    // Now that unification is complete, take a snapshot of the supernode forest,
     // and resolve each arbitrarily-chosen successor to its canonical root.
     // (This avoids having to explicitly resolve them later.)
-        let supernodes = supernodes.freeze();
+    let supernodes = supernodes.snapshot();
-        let succ_supernodes = successors.into_iter().map(|succ| supernodes.find(succ)).collect();
+    let succ_supernodes = successors.into_iter().map(|succ| supernodes[succ]).collect();
 
-        Self { supernodes, succ_supernodes }
+    NodeFlowData { supernodes, succ_supernodes }
-    }
+}
 
-    fn num_nodes(&self) -> usize {
+/// Uses the graph information in `node_flow_data`, together with a given
-        self.succ_supernodes.len()
+/// permutation of all nodes in the graph, to create physical counters and
-    }
+/// counter expressions for each node in the underlying graph.
+///
+/// The given list must contain exactly one copy of each node in the
+/// underlying balanced-flow graph. The order of nodes is used as a hint to
+/// influence counter allocation:
+/// - Earlier nodes are more likely to receive counter expressions.
+/// - Later nodes are more likely to receive physical counters.
+pub(crate) fn make_node_counters<Node: Idx>(
+    node_flow_data: &NodeFlowData<Node>,
+    priority_list: &[Node],
+) -> NodeCounters<Node> {
+    let mut builder = SpantreeBuilder::new(node_flow_data);
 
-    fn is_supernode(&self, node: Node) -> bool {
+    for &node in priority_list {
-        self.supernodes.find(node) == node
-    }
-
-    /// Using the information in this merged graph, together with a given
-    /// permutation of all nodes in the graph, to create physical counters and
-    /// counter expressions for each node in the underlying graph.
-    ///
-    /// The given list must contain exactly one copy of each node in the
-    /// underlying balanced-flow graph. The order of nodes is used as a hint to
-    /// influence counter allocation:
-    /// - Earlier nodes are more likely to receive counter expressions.
-    /// - Later nodes are more likely to receive physical counters.
-    pub(crate) fn make_node_counters(&self, all_nodes_permutation: &[Node]) -> NodeCounters<Node> {
-        let mut builder = SpantreeBuilder::new(self);
-
-        for &node in all_nodes_permutation {
         builder.visit_node(node);
     }
 
-        NodeCounters { counter_exprs: builder.finish() }
+    NodeCounters { counter_terms: builder.finish() }
-    }
 }
 
 /// End result of allocating physical counters and counter expressions for the
 /// nodes of a graph.
 #[derive(Debug)]
 pub(crate) struct NodeCounters<Node: Idx> {
-    counter_exprs: IndexVec<Node, CounterExprVec<Node>>,
-}
-
-impl<Node: Idx> NodeCounters<Node> {
     /// For the given node, returns the finished list of terms that represent
     /// its physical counter or counter expression. Always non-empty.
     ///
-    /// If a node was given a physical counter, its "expression" will contain
+    /// If a node was given a physical counter, the term list will contain
     /// that counter as its sole element.
-    pub(crate) fn counter_expr(&self, this: Node) -> &[CounterTerm<Node>] {
+    pub(crate) counter_terms: IndexVec<Node, Vec<CounterTerm<Node>>>,
-        self.counter_exprs[this].as_slice()
-    }
 }
 
 #[derive(Debug)]
@@ -146,12 +132,11 @@ pub(crate) struct CounterTerm<Node> {
     pub(crate) node: Node,
 }
 
-/// Stores the list of counter terms that make up a node's counter expression.
-type CounterExprVec<Node> = SmallVec<[CounterTerm<Node>; 2]>;
-
 #[derive(Debug)]
 struct SpantreeBuilder<'a, Node: Idx> {
-    graph: &'a MergedNodeFlowGraph<Node>,
+    supernodes: &'a IndexSlice<Node, Node>,
+    succ_supernodes: &'a IndexSlice<Node, Node>,
+
     is_unvisited: DenseBitSet<Node>,
     /// Links supernodes to each other, gradually forming a spanning tree of
     /// the merged-flow graph.
@@ -163,26 +148,32 @@ struct SpantreeBuilder<'a, Node: Idx> {
     yank_buffer: Vec<Node>,
     /// An in-progress counter expression for each node. Each expression is
     /// initially empty, and will be filled in as relevant nodes are visited.
-    counter_exprs: IndexVec<Node, CounterExprVec<Node>>,
+    counter_terms: IndexVec<Node, Vec<CounterTerm<Node>>>,
 }
 
 impl<'a, Node: Idx> SpantreeBuilder<'a, Node> {
-    fn new(graph: &'a MergedNodeFlowGraph<Node>) -> Self {
+    fn new(node_flow_data: &'a NodeFlowData<Node>) -> Self {
-        let num_nodes = graph.num_nodes();
+        let NodeFlowData { supernodes, succ_supernodes } = node_flow_data;
+        let num_nodes = supernodes.len();
         Self {
-            graph,
+            supernodes,
+            succ_supernodes,
             is_unvisited: DenseBitSet::new_filled(num_nodes),
             span_edges: IndexVec::from_fn_n(|_| None, num_nodes),
             yank_buffer: vec![],
-            counter_exprs: IndexVec::from_fn_n(|_| SmallVec::new(), num_nodes),
+            counter_terms: IndexVec::from_fn_n(|_| vec![], num_nodes),
         }
     }
 
+    fn is_supernode(&self, node: Node) -> bool {
+        self.supernodes[node] == node
+    }
+
     /// Given a supernode, finds the supernode that is the "root" of its
     /// spantree component. Two nodes that have the same spantree root are
     /// connected in the spantree.
     fn spantree_root(&self, this: Node) -> Node {
-        debug_assert!(self.graph.is_supernode(this));
+        debug_assert!(self.is_supernode(this));
 
         match self.span_edges[this] {
             None => this,
@@ -193,7 +184,7 @@ impl<'a, Node: Idx> SpantreeBuilder<'a, Node> {
     /// Rotates edges in the spantree so that `this` is the root of its
     /// spantree component.
     fn yank_to_spantree_root(&mut self, this: Node) {
-        debug_assert!(self.graph.is_supernode(this));
+        debug_assert!(self.is_supernode(this));
 
         // The rotation is done iteratively, by first traversing from `this` to
         // its root and storing the path in a buffer, and then traversing the
@@ -235,12 +226,12 @@ impl<'a, Node: Idx> SpantreeBuilder<'a, Node> {
 
         // Get the supernode containing `this`, and make it the root of its
         // component of the spantree.
-        let this_supernode = self.graph.supernodes.find(this);
+        let this_supernode = self.supernodes[this];
         self.yank_to_spantree_root(this_supernode);
 
         // Get the supernode containing all of this's successors.
-        let succ_supernode = self.graph.succ_supernodes[this];
+        let succ_supernode = self.succ_supernodes[this];
-        debug_assert!(self.graph.is_supernode(succ_supernode));
+        debug_assert!(self.is_supernode(succ_supernode));
 
         // If two supernodes are already connected in the spantree, they will
         // have the same spantree root. (Each supernode is connected to itself.)
@@ -268,8 +259,8 @@ impl<'a, Node: Idx> SpantreeBuilder<'a, Node> {
             // `this_supernode`.
 
             // Instead of setting `this.measure = true` as in the original paper,
-            // we just add the node's ID to its own "expression".
+            // we just add the node's ID to its own list of terms.
-            self.counter_exprs[this].push(CounterTerm { node: this, op: Op::Add });
+            self.counter_terms[this].push(CounterTerm { node: this, op: Op::Add });
 
             // Walk the spantree from `this.successor` back to `this`. For each
             // spantree edge along the way, add this node's physical counter to
@@ -279,7 +270,7 @@ impl<'a, Node: Idx> SpantreeBuilder<'a, Node> {
                 let &SpantreeEdge { is_reversed, claiming_node, span_parent } =
                     self.span_edges[curr].as_ref().unwrap();
                 let op = if is_reversed { Op::Subtract } else { Op::Add };
-                self.counter_exprs[claiming_node].push(CounterTerm { node: this, op });
+                self.counter_terms[claiming_node].push(CounterTerm { node: this, op });
 
                 curr = span_parent;
             }
@@ -288,19 +279,20 @@ impl<'a, Node: Idx> SpantreeBuilder<'a, Node> {
 
     /// Asserts that all nodes have been visited, and returns the computed
     /// counter expressions (made up of physical counters) for each node.
-    fn finish(self) -> IndexVec<Node, CounterExprVec<Node>> {
+    fn finish(self) -> IndexVec<Node, Vec<CounterTerm<Node>>> {
-        let Self { graph, is_unvisited, span_edges, yank_buffer: _, counter_exprs } = self;
+        let Self { ref span_edges, ref is_unvisited, ref counter_terms, .. } = self;
         assert!(is_unvisited.is_empty(), "some nodes were never visited: {is_unvisited:?}");
         debug_assert!(
             span_edges
                 .iter_enumerated()
-                .all(|(node, span_edge)| { span_edge.is_some() <= graph.is_supernode(node) }),
+                .all(|(node, span_edge)| { span_edge.is_some() <= self.is_supernode(node) }),
             "only supernodes can have a span edge",
         );
         debug_assert!(
-            counter_exprs.iter().all(|expr| !expr.is_empty()),
+            counter_terms.iter().all(|terms| !terms.is_empty()),
-            "after visiting all nodes, every node should have a non-empty expression",
+            "after visiting all nodes, every node should have at least one term",
         );
-        counter_exprs
+
+        self.counter_terms
     }
 }

compiler/rustc_mir_transform/src/coverage/counters/node_flow/tests.rs

@@ -4,10 +4,12 @@ use rustc_data_structures::graph::vec_graph::VecGraph;
 use rustc_index::Idx;
 use rustc_middle::mir::coverage::Op;
 
-use super::{CounterTerm, MergedNodeFlowGraph, NodeCounters};
+use crate::coverage::counters::node_flow::{
+    CounterTerm, NodeCounters, NodeFlowData, make_node_counters, node_flow_data_for_balanced_graph,
+};
 
-fn merged_node_flow_graph<G: graph::Successors>(graph: G) -> MergedNodeFlowGraph<G::Node> {
+fn node_flow_data<G: graph::Successors>(graph: G) -> NodeFlowData<G::Node> {
-    MergedNodeFlowGraph::for_balanced_graph(graph)
+    node_flow_data_for_balanced_graph(graph)
 }
 
 fn make_graph<Node: Idx + Ord>(num_nodes: usize, edge_pairs: Vec<(Node, Node)>) -> VecGraph<Node> {
@@ -30,8 +32,8 @@ fn example_driver() {
         (4, 0),
     ]);
 
-    let merged = merged_node_flow_graph(&graph);
+    let node_flow_data = node_flow_data(&graph);
-    let counters = merged.make_node_counters(&[3, 1, 2, 0, 4]);
+    let counters = make_node_counters(&node_flow_data, &[3, 1, 2, 0, 4]);
 
     assert_eq!(format_counter_expressions(&counters), &[
         // (comment to force vertical formatting for clarity)
@@ -53,12 +55,12 @@ fn format_counter_expressions<Node: Idx>(counters: &NodeCounters<Node>) -> Vec<S
     };
 
     counters
-        .counter_exprs
+        .counter_terms
         .indices()
         .map(|node| {
-            let mut expr = counters.counter_expr(node).iter().collect::<Vec<_>>();
+            let mut terms = counters.counter_terms[node].iter().collect::<Vec<_>>();
-            expr.sort_by_key(|item| item.node.index());
+            terms.sort_by_key(|item| item.node.index());
-            format!("[{node:?}]: {}", expr.into_iter().map(format_item).join(" "))
+            format!("[{node:?}]: {}", terms.into_iter().map(format_item).join(" "))
         })
         .collect()
 }

compiler/rustc_mir_transform/src/coverage/counters/union_find.rs

@@ -88,29 +88,9 @@ impl<Key: Idx> UnionFind<Key> {
         a
     }
 
-    /// Creates a snapshot of this disjoint-set forest that can no longer be
+    /// Takes a "snapshot" of the current state of this disjoint-set forest, in
-    /// mutated, but can be queried without mutation.
+    /// the form of a vector that directly maps each key to its current root.
-    pub(crate) fn freeze(&mut self) -> FrozenUnionFind<Key> {
+    pub(crate) fn snapshot(&mut self) -> IndexVec<Key, Key> {
-        // Just resolve each key to its actual root.
+        self.table.indices().map(|key| self.find(key)).collect()
-        let roots = self.table.indices().map(|key| self.find(key)).collect();
-        FrozenUnionFind { roots }
-    }
-}
-
-/// Snapshot of a disjoint-set forest that can no longer be mutated, but can be
-/// queried in O(1) time without mutation.
-///
-/// This is really just a wrapper around a direct mapping from keys to roots,
-/// but with a [`Self::find`] method that resembles [`UnionFind::find`].
-#[derive(Debug)]
-pub(crate) struct FrozenUnionFind<Key: Idx> {
-    roots: IndexVec<Key, Key>,
-}
-
-impl<Key: Idx> FrozenUnionFind<Key> {
-    /// Returns the "root" key of the disjoint-set containing the given key.
-    /// If two keys have the same root, they belong to the same set.
-    pub(crate) fn find(&self, key: Key) -> Key {
-        self.roots[key]
     }
 }

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -180,7 +180,12 @@ fn create_mappings(
     ));
 
     for (decision, branches) in mcdc_mappings {
-        let num_conditions = branches.len() as u16;
+        // FIXME(#134497): Previously it was possible for some of these branch
+        // conversions to fail, in which case the remaining branches in the
+        // decision would be degraded to plain `MappingKind::Branch`.
+        // The changes in #134497 made that failure impossible, because the
+        // fallible step was deferred to codegen. But the corresponding code
+        // in codegen wasn't updated to detect the need for a degrade step.
         let conditions = branches
             .into_iter()
             .map(
@@ -206,24 +211,13 @@ fn create_mappings(
             )
             .collect::<Vec<_>>();
 
-        if conditions.len() == num_conditions as usize {
         // LLVM requires end index for counter mapping regions.
         let kind = MappingKind::MCDCDecision(DecisionInfo {
             bitmap_idx: (decision.bitmap_idx + decision.num_test_vectors) as u32,
-                num_conditions,
+            num_conditions: u16::try_from(conditions.len()).unwrap(),
         });
         let span = decision.span;
         mappings.extend(std::iter::once(Mapping { kind, span }).chain(conditions.into_iter()));
-        } else {
-            mappings.extend(conditions.into_iter().map(|mapping| {
-                let MappingKind::MCDCBranch { true_term, false_term, mcdc_params: _ } =
-                    mapping.kind
-                else {
-                    unreachable!("all mappings here are MCDCBranch as shown above");
-                };
-                Mapping { kind: MappingKind::Branch { true_term, false_term }, span: mapping.span }
-            }))
-        }
     }
 
     mappings

compiler/rustc_mir_transform/src/coverage/query.rs

@@ -87,15 +87,9 @@ fn coverage_attr_on(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
 fn coverage_ids_info<'tcx>(
     tcx: TyCtxt<'tcx>,
     instance_def: ty::InstanceKind<'tcx>,
-) -> CoverageIdsInfo {
+) -> Option<CoverageIdsInfo> {
     let mir_body = tcx.instance_mir(instance_def);
-
+    let fn_cov_info = mir_body.function_coverage_info.as_deref()?;
-    let Some(fn_cov_info) = mir_body.function_coverage_info.as_deref() else {
-        return CoverageIdsInfo {
-            counters_seen: DenseBitSet::new_empty(0),
-            zero_expressions: DenseBitSet::new_empty(0),
-        };
-    };
 
     let mut counters_seen = DenseBitSet::new_empty(fn_cov_info.num_counters);
     let mut expressions_seen = DenseBitSet::new_filled(fn_cov_info.expressions.len());
@@ -129,7 +123,7 @@ fn coverage_ids_info<'tcx>(
     let zero_expressions =
         identify_zero_expressions(fn_cov_info, &counters_seen, &expressions_seen);
 
-    CoverageIdsInfo { counters_seen, zero_expressions }
+    Some(CoverageIdsInfo { counters_seen, zero_expressions })
 }
 
 fn all_coverage_in_mir_body<'a, 'tcx>(

library/alloc/src/vec/mod.rs

@@ -2511,9 +2511,9 @@ impl<T, A: Allocator> Vec<T, A> {
         }
     }
 
-    /// Removes and returns the last element in a vector if the predicate
+    /// Removes and returns the last element from a vector if the predicate
     /// returns `true`, or [`None`] if the predicate returns false or the vector
-    /// is empty.
+    /// is empty (the predicate will not be called in that case).
     ///
     /// # Examples
     ///
@@ -2528,12 +2528,9 @@ impl<T, A: Allocator> Vec<T, A> {
     /// assert_eq!(vec.pop_if(pred), None);
     /// ```
     #[unstable(feature = "vec_pop_if", issue = "122741")]
-    pub fn pop_if<F>(&mut self, f: F) -> Option<T>
+    pub fn pop_if(&mut self, predicate: impl FnOnce(&mut T) -> bool) -> Option<T> {
-    where
-        F: FnOnce(&mut T) -> bool,
-    {
         let last = self.last_mut()?;
-        if f(last) { self.pop() } else { None }
+        if predicate(last) { self.pop() } else { None }
     }
 
     /// Moves all the elements of `other` into `self`, leaving `other` empty.
@@ -3016,10 +3013,9 @@ impl<T: Clone, A: Allocator> Vec<T, A> {
     /// Iterates over the slice `other`, clones each element, and then appends
     /// it to this `Vec`. The `other` slice is traversed in-order.
     ///
-    /// Note that this function is same as [`extend`] except that it is
+    /// Note that this function is the same as [`extend`],
-    /// specialized to work with slices instead. If and when Rust gets
+    /// except that it also works with slice elements that are Clone but not Copy.
-    /// specialization this function will likely be deprecated (but still
+    /// If Rust gets specialization this function may be deprecated.
-    /// available).
     ///
     /// # Examples
     ///

src/doc/rustc-dev-guide/src/conventions.md

@@ -25,6 +25,7 @@ pass the <!-- date-check: nov 2022 --> `--edition=2021` argument yourself when c
 `rustfmt` directly.
 
 [fmt]: https://github.com/rust-dev-tools/fmt-rfcs
+
 [`rustfmt`]:https://github.com/rust-lang/rustfmt
 
 ## Formatting C++ code
@@ -40,6 +41,26 @@ When modifying that code, use this command to format it:
 This uses a pinned version of `clang-format`, to avoid relying on the local
 environment.
 
+## Formatting and linting Python code
+
+The Rust repository contains quite a lof of Python code. We try to keep
+it both linted and formatted by the [ruff][ruff] tool.
+
+When modifying Python code, use this command to format it:
+```sh
+./x test tidy --extra-checks=py:fmt --bless
+```
+
+and the following command to run lints:
+```sh
+./x test tidy --extra-checks=py:lint
+```
+
+This uses a pinned version of `ruff`, to avoid relying on the local
+environment.
+
+[ruff]: https://github.com/astral-sh/ruff
+
 <a id="copyright"></a>
 
 <!-- REUSE-IgnoreStart -->
@@ -165,4 +186,5 @@ to the compiler.
   crate-related, often the spelling is changed to `krate`.
 
 [tcx]: ./ty.md
+
 [crates]: ./crates-io.md

src/doc/rustc-dev-guide/src/tests/directives.md

@@ -176,6 +176,7 @@ settings:
 - `needs-rust-lld` — ignores if the rust lld support is not enabled (`rust.lld =
   true` in `config.toml`)
 - `needs-threads` — ignores if the target does not have threading support
+- `needs-subprocess`  — ignores if the target does not have subprocess support
 - `needs-symlink` — ignores if the target does not support symlinks. This can be
   the case on Windows if the developer did not enable privileged symlink
   permissions.

src/tools/compiletest/src/common.rs

@@ -488,6 +488,17 @@ impl Config {
             git_merge_commit_email: &self.git_merge_commit_email,
         }
     }
+
+    pub fn has_subprocess_support(&self) -> bool {
+        // FIXME(#135928): compiletest is always a **host** tool. Building and running an
+        // capability detection executable against the **target** is not trivial. The short term
+        // solution here is to hard-code some targets to allow/deny, unfortunately.
+
+        let unsupported_target = self.target_cfg().env == "sgx"
+            || matches!(self.target_cfg().arch.as_str(), "wasm32" | "wasm64")
+            || self.target_cfg().os == "emscripten";
+        !unsupported_target
+    }
 }
 
 /// Known widths of `target_has_atomic`.

src/tools/compiletest/src/directive-list.rs

@@ -152,6 +152,7 @@ const KNOWN_DIRECTIVE_NAMES: &[&str] = &[
     "needs-sanitizer-support",
     "needs-sanitizer-thread",
     "needs-std-debug-assertions",
+    "needs-subprocess",
     "needs-symlink",
     "needs-target-has-atomic",
     "needs-threads",

src/tools/compiletest/src/header/needs.rs

@@ -94,6 +94,11 @@ pub(super) fn handle_needs(
             condition: config.has_threads(),
             ignore_reason: "ignored on targets without threading support",
         },
+        Need {
+            name: "needs-subprocess",
+            condition: config.has_subprocess_support(),
+            ignore_reason: "ignored on targets without subprocess support",
+        },
         Need {
             name: "needs-unwind",
             condition: config.can_unwind(),
@@ -351,6 +356,9 @@ fn find_dlltool(config: &Config) -> bool {
     dlltool_found
 }
 
+// FIXME(#135928): this is actually not quite right because this detection is run on the **host**.
+// This however still helps the case of windows -> windows local development in case symlinks are
+// not available.
 #[cfg(windows)]
 fn has_symlinks() -> bool {
     if std::env::var_os("CI").is_some() {

src/tools/tidy/src/ext_tool_checks.rs

@@ -89,74 +89,45 @@ fn check_impl(
 
     if python_lint {
         eprintln!("linting python files");
-        let mut cfg_args_ruff = cfg_args.clone();
+        let py_path = py_path.as_ref().unwrap();
-        let mut file_args_ruff = file_args.clone();
+        let res = run_ruff(root_path, outdir, py_path, &cfg_args, &file_args, &["check".as_ref()]);
-
-        let mut cfg_path = root_path.to_owned();
-        cfg_path.extend(RUFF_CONFIG_PATH);
-        let mut cache_dir = outdir.to_owned();
-        cache_dir.extend(RUFF_CACHE_PATH);
-
-        cfg_args_ruff.extend([
-            "--config".as_ref(),
-            cfg_path.as_os_str(),
-            "--cache-dir".as_ref(),
-            cache_dir.as_os_str(),
-        ]);
-
-        if file_args_ruff.is_empty() {
-            file_args_ruff.push(root_path.as_os_str());
-        }
-
-        let mut args = merge_args(&cfg_args_ruff, &file_args_ruff);
-        args.insert(0, "check".as_ref());
-        let res = py_runner(py_path.as_ref().unwrap(), true, None, "ruff", &args);
 
         if res.is_err() && show_diff {
             eprintln!("\npython linting failed! Printing diff suggestions:");
 
-            args.insert(1, "--diff".as_ref());
+            let _ = run_ruff(root_path, outdir, py_path, &cfg_args, &file_args, &[
-            let _ = py_runner(py_path.as_ref().unwrap(), true, None, "ruff", &args);
+                "check".as_ref(),
+                "--diff".as_ref(),
+            ]);
         }
         // Rethrow error
         let _ = res?;
     }
 
     if python_fmt {
-        let mut cfg_args_ruff = cfg_args.clone();
+        let mut args: Vec<&OsStr> = vec!["format".as_ref()];
-        let mut file_args_ruff = file_args.clone();
-
         if bless {
             eprintln!("formatting python files");
         } else {
             eprintln!("checking python file formatting");
-            cfg_args_ruff.push("--check".as_ref());
+            args.push("--check".as_ref());
         }
 
-        let mut cfg_path = root_path.to_owned();
+        let py_path = py_path.as_ref().unwrap();
-        cfg_path.extend(RUFF_CONFIG_PATH);
+        let res = run_ruff(root_path, outdir, py_path, &cfg_args, &file_args, &args);
-        let mut cache_dir = outdir.to_owned();
-        cache_dir.extend(RUFF_CACHE_PATH);
 
-        cfg_args_ruff.extend(["--config".as_ref(), cfg_path.as_os_str()]);
+        if res.is_err() && !bless {
-
+            if show_diff {
-        if file_args_ruff.is_empty() {
-            file_args_ruff.push(root_path.as_os_str());
-        }
-
-        let mut args = merge_args(&cfg_args_ruff, &file_args_ruff);
-        args.insert(0, "format".as_ref());
-        let res = py_runner(py_path.as_ref().unwrap(), true, None, "ruff", &args);
-
-        if res.is_err() && show_diff {
                 eprintln!("\npython formatting does not match! Printing diff:");
 
-            args.insert(0, "--diff".as_ref());
+                let _ = run_ruff(root_path, outdir, py_path, &cfg_args, &file_args, &[
-            let _ = py_runner(py_path.as_ref().unwrap(), true, None, "ruff", &args);
+                    "format".as_ref(),
+                    "--diff".as_ref(),
+                ]);
             }
-        if res.is_err() && !bless {
             eprintln!("rerun tidy with `--extra-checks=py:fmt --bless` to reformat Python code");
         }
+
         // Rethrow error
         let _ = res?;
     }
@@ -247,6 +218,38 @@ fn check_impl(
     Ok(())
 }
 
+fn run_ruff(
+    root_path: &Path,
+    outdir: &Path,
+    py_path: &Path,
+    cfg_args: &[&OsStr],
+    file_args: &[&OsStr],
+    ruff_args: &[&OsStr],
+) -> Result<(), Error> {
+    let mut cfg_args_ruff = cfg_args.into_iter().copied().collect::<Vec<_>>();
+    let mut file_args_ruff = file_args.into_iter().copied().collect::<Vec<_>>();
+
+    let mut cfg_path = root_path.to_owned();
+    cfg_path.extend(RUFF_CONFIG_PATH);
+    let mut cache_dir = outdir.to_owned();
+    cache_dir.extend(RUFF_CACHE_PATH);
+
+    cfg_args_ruff.extend([
+        "--config".as_ref(),
+        cfg_path.as_os_str(),
+        "--cache-dir".as_ref(),
+        cache_dir.as_os_str(),
+    ]);
+
+    if file_args_ruff.is_empty() {
+        file_args_ruff.push(root_path.as_os_str());
+    }
+
+    let mut args: Vec<&OsStr> = ruff_args.into_iter().copied().collect();
+    args.extend(merge_args(&cfg_args_ruff, &file_args_ruff));
+    py_runner(py_path, true, None, "ruff", &args)
+}
+
 /// Helper to create `cfg1 cfg2 -- file1 file2` output
 fn merge_args<'a>(cfg_args: &[&'a OsStr], file_args: &[&'a OsStr]) -> Vec<&'a OsStr> {
     let mut args = cfg_args.to_owned();
@@ -321,8 +324,16 @@ fn get_or_create_venv(venv_path: &Path, src_reqs_path: &Path) -> Result<PathBuf,
 fn create_venv_at_path(path: &Path) -> Result<(), Error> {
     /// Preferred python versions in order. Newest to oldest then current
     /// development versions
-    const TRY_PY: &[&str] =
+    const TRY_PY: &[&str] = &[
-        &["python3.11", "python3.10", "python3.9", "python3", "python", "python3.12", "python3.13"];
+        "python3.13",
+        "python3.12",
+        "python3.11",
+        "python3.10",
+        "python3.9",
+        "python3",
+        "python",
+        "python3.14",
+    ];
 
     let mut sys_py = None;
     let mut found = Vec::new();
@@ -357,22 +368,40 @@ fn create_venv_at_path(path: &Path) -> Result<(), Error> {
         return Err(ret);
     };
 
-    eprintln!("creating virtual environment at '{}' using '{sys_py}'", path.display());
+    // First try venv, which should be packaged in the Python3 standard library.
-    let out = Command::new(sys_py).args(["-m", "virtualenv"]).arg(path).output().unwrap();
+    // If it is not available, try to create the virtual environment using the
+    // virtualenv package.
+    if try_create_venv(sys_py, path, "venv").is_ok() {
+        return Ok(());
+    }
+    try_create_venv(sys_py, path, "virtualenv")
+}
+
+fn try_create_venv(python: &str, path: &Path, module: &str) -> Result<(), Error> {
+    eprintln!(
+        "creating virtual environment at '{}' using '{python}' and '{module}'",
+        path.display()
+    );
+    let out = Command::new(python).args(["-m", module]).arg(path).output().unwrap();
 
     if out.status.success() {
         return Ok(());
     }
 
     let stderr = String::from_utf8_lossy(&out.stderr);
-    let err = if stderr.contains("No module named virtualenv") {
+    let err = if stderr.contains(&format!("No module named {module}")) {
         Error::Generic(format!(
-            "virtualenv not found: you may need to install it \
+            r#"{module} not found: you may need to install it:
-                               (`{sys_py} -m pip install virtualenv`)"
+`{python} -m pip install {module}`
+If you see an error about "externally managed environment" when running the above command,
+either install `{module}` using your system package manager
+(e.g. `sudo apt-get install {python}-{module}`) or create a virtual environment manually, install
+`{module}` in it and then activate it before running tidy.
+"#
         ))
     } else {
         Error::Generic(format!(
-            "failed to create venv at '{}' using {sys_py}: {stderr}",
+            "failed to create venv at '{}' using {python} -m {module}: {stderr}",
             path.display()
         ))
     };

src/tools/tidy/src/issues.txt

@@ -2204,7 +2204,6 @@ ui/issues/issue-3895.rs
 ui/issues/issue-38954.rs
 ui/issues/issue-38987.rs
 ui/issues/issue-39089.rs
-ui/issues/issue-39175.rs
 ui/issues/issue-39211.rs
 ui/issues/issue-39367.rs
 ui/issues/issue-39548.rs

src/tools/tidy/src/ui_tests.rs

@@ -17,7 +17,7 @@ use ignore::Walk;
 const ENTRY_LIMIT: u32 = 901;
 // FIXME: The following limits should be reduced eventually.
 
-const ISSUES_ENTRY_LIMIT: u32 = 1664;
+const ISSUES_ENTRY_LIMIT: u32 = 1662;
 
 const EXPECTED_TEST_FILE_EXTENSIONS: &[&str] = &[
     "rs",     // test source files

tests/assembly/powerpc64-struct-abi.rs

@@ -50,9 +50,9 @@ struct ThreeU8s(u8, u8, u8);
 
 // CHECK-LABEL: read_large
 // aix: lwz [[REG1:.*]], 16(4)
-// aix-NEXT: lxvd2x 0, 0, 4
+// aix-NEXT: lxv{{d2x|w4x}} 0, 0, 4
 // aix-NEXT: stw [[REG1]], 16(3)
-// aix-NEXT: stxvd2x 0, 0, 3
+// aix-NEXT: stxv{{d2x|w4x}} 0, 0, 3
 // be: lwz [[REG1:.*]], 16(4)
 // be-NEXT: stw [[REG1]], 16(3)
 // be-NEXT: ld [[REG2:.*]], 8(4)
@@ -118,8 +118,8 @@ extern "C" fn read_small(x: &ThreeU8s) -> ThreeU8s {
 // aix-NEXT: std 4, 56(1)
 // aix-NEXT: stw [[REG1]], 16(6)
 // aix-NEXT: addi [[REG2:.*]], 1, 48
-// aix-NEXT: lxvd2x 0, 0, [[REG2]]
+// aix-NEXT: lxv{{d2x|w4x}} 0, 0, [[REG2]]
-// aix-NEXT: stxvd2x 0, 0, 6
+// aix-NEXT: stxv{{d2x|w4x}} 0, 0, 6
 // elf: std 3, 0(6)
 // be-NEXT: rldicl [[REG1:.*]], 5, 32, 32
 // elf-NEXT: std 4, 8(6)

tests/mir-opt/coverage/instrument_coverage.bar.InstrumentCoverage.diff

@@ -4,8 +4,8 @@
   fn bar() -> bool {
       let mut _0: bool;
   
-+     coverage body span: $DIR/instrument_coverage.rs:19:18: 21:2 (#0)
++     coverage body span: $DIR/instrument_coverage.rs:29:18: 31:2 (#0)
-+     coverage Code(Counter(0)) => $DIR/instrument_coverage.rs:19:1: 21:2 (#0);
++     coverage Code(Counter(0)) => $DIR/instrument_coverage.rs:29:1: 31:2 (#0);
 + 
       bb0: {
 +         Coverage::CounterIncrement(0);

tests/mir-opt/coverage/instrument_coverage.main.InstrumentCoverage.diff

@@ -7,13 +7,13 @@
       let mut _2: bool;
       let mut _3: !;
   
-+     coverage body span: $DIR/instrument_coverage.rs:10:11: 16:2 (#0)
++     coverage body span: $DIR/instrument_coverage.rs:14:11: 20:2 (#0)
 +     coverage ExpressionId(0) => Expression { lhs: Counter(1), op: Subtract, rhs: Counter(0) };
-+     coverage Code(Counter(0)) => $DIR/instrument_coverage.rs:10:1: 10:11 (#0);
++     coverage Code(Counter(0)) => $DIR/instrument_coverage.rs:14:1: 14:11 (#0);
-+     coverage Code(Counter(1)) => $DIR/instrument_coverage.rs:12:12: 12:17 (#0);
++     coverage Code(Counter(1)) => $DIR/instrument_coverage.rs:16:12: 16:17 (#0);
-+     coverage Code(Counter(0)) => $DIR/instrument_coverage.rs:13:13: 13:18 (#0);
++     coverage Code(Counter(0)) => $DIR/instrument_coverage.rs:17:13: 17:18 (#0);
-+     coverage Code(Expression(0)) => $DIR/instrument_coverage.rs:14:10: 14:10 (#0);
++     coverage Code(Expression(0)) => $DIR/instrument_coverage.rs:18:10: 18:10 (#0);
-+     coverage Code(Counter(0)) => $DIR/instrument_coverage.rs:16:2: 16:2 (#0);
++     coverage Code(Counter(0)) => $DIR/instrument_coverage.rs:20:2: 20:2 (#0);
 + 
       bb0: {
 +         Coverage::CounterIncrement(0);

tests/mir-opt/coverage/instrument_coverage.rs

@@ -6,7 +6,11 @@
 //@ compile-flags: -Cinstrument-coverage -Zno-profiler-runtime
 
 // EMIT_MIR instrument_coverage.main.InstrumentCoverage.diff
-// EMIT_MIR instrument_coverage.bar.InstrumentCoverage.diff
+// CHECK-LABEL: fn main()
+// CHECK: coverage body span:
+// CHECK: coverage Code(Counter({{[0-9]+}})) =>
+// CHECK: bb0:
+// CHECK: Coverage::CounterIncrement
 fn main() {
     loop {
         if bar() {
@@ -15,14 +19,13 @@ fn main() {
     }
 }
 
+// EMIT_MIR instrument_coverage.bar.InstrumentCoverage.diff
+// CHECK-LABEL: fn bar()
+// CHECK: coverage body span:
+// CHECK: coverage Code(Counter({{[0-9]+}})) =>
+// CHECK: bb0:
+// CHECK: Coverage::CounterIncrement
 #[inline(never)]
 fn bar() -> bool {
     true
 }
-
-// CHECK:     coverage ExpressionId({{[0-9]+}}) =>
-// CHECK-DAG: coverage Code(Counter({{[0-9]+}})) =>
-// CHECK-DAG: coverage Code(Expression({{[0-9]+}})) =>
-// CHECK:     bb0:
-// CHECK-DAG: Coverage::ExpressionUsed({{[0-9]+}})
-// CHECK-DAG: Coverage::CounterIncrement({{[0-9]+}})

tests/ui/abi/homogenous-floats-target-feature-mixup.rs

@@ -5,8 +5,7 @@
 // without #[repr(simd)]
 
 //@ run-pass
-//@ ignore-wasm32 no processes
+//@ needs-subprocess
-//@ ignore-sgx no processes
 
 #![feature(avx512_target_feature)]
 

tests/ui/abi/segfault-no-out-of-stack.rs

@@ -1,6 +1,5 @@
 //@ run-pass
-//@ ignore-wasm32 can't run commands
+//@ needs-subprocess
-//@ ignore-sgx no processes
 //@ ignore-fuchsia must translate zircon signal to SIGSEGV/SIGBUS, FIXME (#58590)
 
 #![feature(rustc_private)]

tests/ui/abi/stack-probes-lto.rs

@@ -3,7 +3,7 @@
 //@[aarch64] only-aarch64
 //@[x32] only-x86
 //@[x64] only-x86_64
-//@ ignore-sgx no processes
+//@ needs-subprocess
 //@ ignore-musl FIXME #31506
 //@ ignore-fuchsia no exception handler registered for segfault
 //@ compile-flags: -C lto

tests/ui/abi/stack-probes.rs

@@ -3,8 +3,7 @@
 //@[aarch64] only-aarch64
 //@[x32] only-x86
 //@[x64] only-x86_64
-//@ ignore-emscripten no processes
+//@ needs-subprocess
-//@ ignore-sgx no processes
 //@ ignore-fuchsia no exception handler registered for segfault
 //@ ignore-nto Crash analysis impossible at SIGSEGV in QNX Neutrino
 //@ ignore-ios Stack probes are enabled, but the SIGSEGV handler isn't

tests/ui/alloc-error/default-alloc-error-hook.rs

@@ -1,6 +1,5 @@
 //@ run-pass
-//@ ignore-wasm32 no processes
+//@ needs-subprocess
-//@ ignore-sgx no processes
 
 use std::alloc::{Layout, handle_alloc_error};
 use std::env;

tests/ui/array-slice-vec/bounds-check-no-overflow.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:index out of bounds
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 use std::mem::size_of;
 

tests/ui/array-slice-vec/box-of-array-of-drop-1.rs

@@ -1,12 +1,12 @@
 //@ run-pass
 //@ needs-unwind
+//@ needs-threads
+
 #![allow(overflowing_literals)]
 
 // Test that we cleanup a fixed size Box<[D; k]> properly when D has a
 // destructor.
 
-//@ ignore-emscripten no threads support
-
 use std::thread;
 use std::sync::atomic::{AtomicUsize, Ordering};
 

tests/ui/array-slice-vec/box-of-array-of-drop-2.rs

@@ -1,12 +1,12 @@
 //@ run-pass
 //@ needs-unwind
+//@ needs-threads
+
 #![allow(overflowing_literals)]
 
 // Test that we cleanup dynamic sized Box<[D]> properly when D has a
 // destructor.
 
-//@ ignore-emscripten no threads support
-
 use std::thread;
 use std::sync::atomic::{AtomicUsize, Ordering};
 

tests/ui/array-slice-vec/dst-raw-slice.rs

@@ -2,7 +2,7 @@
 
 //@ run-fail
 //@ error-pattern:index out of bounds
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 #[allow(unconditional_panic)]
 fn main() {

tests/ui/array-slice-vec/nested-vec-3.rs

@@ -1,8 +1,8 @@
 //@ run-pass
 //@ needs-unwind
-#![allow(overflowing_literals)]
+//@ needs-threads
 
-//@ ignore-emscripten no threads support
+#![allow(overflowing_literals)]
 
 // Test that using the `vec!` macro nested within itself works when
 // the contents implement Drop and we hit a panic in the middle of

tests/ui/array-slice-vec/slice-panic-1.rs

@@ -1,7 +1,6 @@
 //@ run-pass
 //@ needs-unwind
-
+//@ needs-threads
-//@ ignore-emscripten no threads support
 
 // Test that if a slicing expr[..] fails, the correct cleanups happen.
 

tests/ui/array-slice-vec/slice-panic-2.rs

@@ -1,7 +1,6 @@
 //@ run-pass
 //@ needs-unwind
-
+//@ needs-threads
-//@ ignore-emscripten no threads support
 
 // Test that if a slicing expr[..] fails, the correct cleanups happen.
 

tests/ui/array-slice-vec/vec-overrun.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:index out of bounds: the len is 1 but the index is 2
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     let v: Vec<isize> = vec![10];

tests/ui/backtrace/backtrace.rs

@@ -1,8 +1,7 @@
 //@ run-pass
 //@ ignore-android FIXME #17520
-//@ ignore-wasm32 spawning processes is not supported
+//@ needs-subprocess
 //@ ignore-openbsd no support for libbacktrace without filename
-//@ ignore-sgx no processes
 //@ ignore-msvc see #62897 and `backtrace-debuginfo.rs` test
 //@ ignore-fuchsia Backtraces not symbolized
 //@ compile-flags:-g

tests/ui/backtrace/std-backtrace.rs

@@ -1,8 +1,7 @@
 //@ run-pass
 //@ ignore-android FIXME #17520
-//@ ignore-wasm32 spawning processes is not supported
+//@ needs-subprocess
 //@ ignore-openbsd no support for libbacktrace without filename
-//@ ignore-sgx no processes
 //@ ignore-fuchsia Backtraces not symbolized
 //@ compile-flags:-g
 //@ compile-flags:-Cstrip=none

tests/ui/binop/binop-fail-3.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:quux
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn foo() -> ! {
     panic!("quux");

tests/ui/binop/binop-panic.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:quux
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn my_err(s: String) -> ! {
     println!("{}", s);

tests/ui/borrowck/borrowck-local-borrow.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:panic 1
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     let x = 2;

tests/ui/borrowck/issue-28934.rs

@@ -3,7 +3,7 @@
 
 //@ run-fail
 //@ error-pattern:explicit panic
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 struct Parser<'i: 't, 't>(&'i u8, &'t u8);
 

tests/ui/box/unit/unwind-unique.rs

@@ -1,6 +1,6 @@
 //@ run-pass
 //@ needs-unwind
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 

tests/ui/cleanup-rvalue-temp-during-incomplete-alloc.rs

@@ -20,7 +20,7 @@
 // It's unclear how likely such a bug is to recur, but it seems like a
 // scenario worth testing.
 
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 

tests/ui/closures/diverging-closure.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:oops
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     let func = || -> ! {

tests/ui/command/command-argv0.rs

@@ -1,8 +1,7 @@
 //@ run-pass
 
-//@ ignore-windows - this is a unix-specific test
+//@ only-unix (this is a unix-specific test)
-//@ ignore-wasm32 no processes
+//@ needs-subprocess
-//@ ignore-sgx no processes
 use std::env;
 use std::os::unix::process::CommandExt;
 use std::process::Command;

tests/ui/command/command-current-dir.rs

@@ -1,7 +1,6 @@
 //@ run-pass
 //@ no-prefer-dynamic We move the binary around, so do not depend dynamically on libstd
-//@ ignore-wasm32 no processes
+//@ needs-subprocess
-//@ ignore-sgx no processes
 //@ ignore-fuchsia Needs directory creation privilege
 
 use std::env;

tests/ui/command/command-exec.rs

@@ -1,13 +1,9 @@
 //@ run-pass
 
-#![allow(stable_features)]
+//@ only-unix (this is a unix-specific test)
-//@ ignore-windows - this is a unix-specific test
+//@ needs-subprocess
-//@ ignore-wasm32 no processes
-//@ ignore-sgx no processes
 //@ ignore-fuchsia no execvp syscall provided
 
-#![feature(process_exec)]
-
 use std::env;
 use std::os::unix::process::CommandExt;
 use std::process::Command;

tests/ui/command/command-pre-exec.rs

@@ -1,11 +1,9 @@
 //@ run-pass
-
+//@ only-unix (this is a unix-specific test)
-#![allow(stable_features)]
+//@ needs-subprocess
-//@ ignore-windows - this is a unix-specific test
-//@ ignore-wasm32 no processes
-//@ ignore-sgx no processes
 //@ ignore-fuchsia no execvp syscall
-#![feature(process_exec, rustc_private)]
+
+#![feature(rustc_private)]
 
 extern crate libc;
 

tests/ui/command/command-setgroups.rs

@@ -1,9 +1,8 @@
 //@ run-pass
-//@ ignore-windows - this is a unix-specific test
+//@ only-unix (this is a unix-specific test)
-//@ ignore-wasm32
-//@ ignore-sgx
 //@ ignore-musl - returns dummy result for _SC_NGROUPS_MAX
 //@ ignore-nto - does not have `/bin/id`, expects groups to be i32 (not u32)
+//@ needs-subprocess
 
 #![feature(rustc_private)]
 #![feature(setgroups)]

tests/ui/command/command-uid-gid.rs

@@ -1,8 +1,7 @@
 //@ run-pass
 //@ ignore-android
-//@ ignore-emscripten
-//@ ignore-sgx
 //@ ignore-fuchsia no '/bin/sh', '/bin/ls'
+//@ needs-subprocess
 
 #![feature(rustc_private)]
 

tests/ui/command/issue-10626.rs

@@ -1,6 +1,5 @@
 //@ run-pass
-//@ ignore-wasm32 no processes
+//@ needs-subprocess
-//@ ignore-sgx no processes
 
 // Make sure that if a process doesn't have its stdio/stderr descriptors set up
 // that we don't die in a large ball of fire

tests/ui/consts/issue-29798.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:index out of bounds: the len is 5 but the index is 5
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 const fn test(x: usize) -> i32 {
     [42;5][x]

tests/ui/coroutine/coroutine-resume-after-panic.rs

@@ -1,7 +1,7 @@
 //@ run-fail
 //@ needs-unwind
 //@ error-pattern:coroutine resumed after panicking
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 // Test that we get the correct message for resuming a panicked coroutine.
 

tests/ui/drop/drop-trait-enum.rs

@@ -2,7 +2,7 @@
 #![allow(dead_code)]
 #![allow(unused_assignments)]
 #![allow(unused_variables)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 //@ needs-unwind
 
 use std::thread;

tests/ui/drop/terminate-in-initializer.rs

@@ -1,6 +1,6 @@
 //@ run-pass
 //@ needs-unwind
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 // Issue #787
 // Don't try to clean up uninitialized locals

tests/ui/expr/if/expr-if-panic-fn.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:explicit panic
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn f() -> ! {
     panic!()

tests/ui/expr/if/expr-if-panic.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:explicit panic
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     let _x = if false {

tests/ui/expr/if/if-check-panic.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:Number is odd
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn even(x: usize) -> bool {
     if x < 2 {

tests/ui/expr/if/if-cond-bot.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:quux
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn my_err(s: String) -> ! {
     println!("{}", s);

tests/ui/extern/issue-18576.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:stop
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 // #18576
 // Make sure that calling an extern function pointer in an unreachable

tests/ui/extern/issue-64655-allow-unwind-when-calling-panic-directly.rs

@@ -1,6 +1,6 @@
 //@ run-pass
 //@ needs-unwind
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 // rust-lang/rust#64655: with panic=unwind, a panic from a subroutine
 // should still run destructors as it unwinds the stack. However,

tests/ui/extern/issue-64655-extern-rust-must-allow-unwind.rs

@@ -1,6 +1,6 @@
 //@ run-pass
 //@ needs-unwind
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 // rust-lang/rust#64655: with panic=unwind, a panic from a subroutine
 // should still run destructors as it unwinds the stack. However,

tests/ui/fn/expr-fn-panic.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:explicit panic
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn f() -> ! {
     panic!()

tests/ui/hashmap/hashmap-capacity-overflow.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:capacity overflow
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 use std::collections::hash_map::HashMap;
 use std::mem::size_of;

tests/ui/imports/glob-use-std.rs

@@ -2,7 +2,7 @@
 
 //@ run-fail
 //@ error-pattern:panic works
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 use std::*;
 

tests/ui/intrinsics/panic-uninitialized-zeroed.rs

@@ -1,11 +1,10 @@
+// ignore-tidy-linelength
+//! This test checks panic emitted from `mem::{uninitialized,zeroed}`.
 //@ run-pass
 //@ revisions: default strict
 //@ [strict]compile-flags: -Zstrict-init-checks
-// ignore-tidy-linelength
+//@ needs-subprocess
-//@ ignore-wasm32 spawning processes is not supported
+
-//@ ignore-sgx no processes
-//
-// This test checks panic emitted from `mem::{uninitialized,zeroed}`.
 #![allow(deprecated, invalid_value)]
 #![feature(never_type)]
 

tests/ui/issues/issue-12920.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:explicit panic
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 pub fn main() {
     panic!();

tests/ui/issues/issue-13202.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:bad input
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     Some("foo").unwrap_or(panic!("bad input")).to_string();

tests/ui/issues/issue-20971.rs

@@ -2,7 +2,7 @@
 
 //@ run-fail
 //@ error-pattern:Hello, world!
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 pub trait Parser {
     type Input;

tests/ui/issues/issue-2190-1.rs

@@ -1,20 +1,16 @@
-//@ run-pass
+//@ check-pass
-#![allow(unused_must_use)]
-#![allow(non_upper_case_globals)]
-
-//@ ignore-emscripten no threads
 
 use std::thread::Builder;
 
-static generations: usize = 1024+256+128+49;
+static GENERATIONS: usize = 1024+256+128+49;
 
 fn spawn(mut f: Box<dyn FnMut() + 'static + Send>) {
-    Builder::new().stack_size(32 * 1024).spawn(move|| f());
+    Builder::new().stack_size(32 * 1024).spawn(move || f());
 }
 
 fn child_no(x: usize) -> Box<dyn FnMut() + 'static + Send> {
-    Box::new(move|| {
+    Box::new(move || {
-        if x < generations {
+        if x < GENERATIONS {
             spawn(child_no(x+1));
         }
     })

tests/ui/issues/issue-23354-2.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:panic evaluated
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 #[allow(unused_variables)]
 fn main() {

tests/ui/issues/issue-23354.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:panic evaluated
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 #[allow(unused_variables)]
 fn main() {

tests/ui/issues/issue-2470-bounds-check-overflow.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:index out of bounds
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 use std::mem;
 

tests/ui/issues/issue-25089.rs

@@ -1,6 +1,6 @@
 //@ run-pass
 //@ needs-unwind
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 

tests/ui/issues/issue-26655.rs

@@ -1,6 +1,6 @@
 //@ run-pass
 //@ needs-unwind
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 // Check that the destructors of simple enums are run on unwinding
 

tests/ui/issues/issue-2761.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:custom message
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     assert!(false, "custom message");

tests/ui/issues/issue-29485.rs

@@ -2,7 +2,7 @@
 #![allow(unused_attributes)]
 //@ aux-build:issue-29485.rs
 //@ needs-unwind
-//@ ignore-emscripten no threads
+//@ needs-threads
 
 #[feature(recover)]
 

tests/ui/issues/issue-30018-panic.rs

@@ -5,7 +5,7 @@
 // SIGTRAP injected by the drop-flag consistency checking.
 
 //@ needs-unwind
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 struct Foo;
 

tests/ui/issues/issue-3029.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:so long
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 #![allow(unreachable_code)]
 

tests/ui/issues/issue-30380.rs

@@ -3,7 +3,7 @@
 
 //@ run-fail
 //@ error-pattern:panicking destructors ftw!
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 struct Observer<'a>(&'a mut FilledOnDrop);
 

tests/ui/issues/issue-33770.rs

@@ -1,6 +1,5 @@
 //@ run-pass
-//@ ignore-wasm32 no processes
+//@ needs-subprocess
-//@ ignore-sgx no processes
 
 use std::process::{Command, Stdio};
 use std::env;

tests/ui/issues/issue-38763.rs

@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten
+//@ needs-threads
 
 #[repr(C)]
 pub struct Foo(i128);

tests/ui/issues/issue-44216-add-system-time.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:overflow
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 use std::time::{Duration, SystemTime};
 

tests/ui/issues/issue-44216-sub-instant.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:overflow
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 use std::time::{Instant, Duration};
 

tests/ui/issues/issue-44216-sub-system-time.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:overflow
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 use std::time::{Duration, SystemTime};
 

tests/ui/lifetimes/tail-expr-lock-poisoning.rs

@@ -1,5 +1,6 @@
 //@ revisions: edition2021 edition2024
-//@ ignore-wasm no panic or subprocess support
+//@ ignore-wasm no panic support
+//@ needs-subprocess
 //@ [edition2024] edition: 2024
 //@ run-pass
 //@ needs-unwind

tests/ui/loops/for-each-loop-panic.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:moop
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     for _ in 0_usize..10_usize {

tests/ui/macros/assert-as-macro.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:assertion failed: 1 == 2
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     assert!(1 == 2);

tests/ui/macros/assert-eq-macro-msg.rs

@@ -2,7 +2,7 @@
 //@ error-pattern:assertion `left == right` failed: 1 + 1 definitely should be 3
 //@ error-pattern:  left: 2
 //@ error-pattern: right: 3
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     assert_eq!(1 + 1, 3, "1 + 1 definitely should be 3");

tests/ui/macros/assert-eq-macro-panic.rs

@@ -2,7 +2,7 @@
 //@ error-pattern:assertion `left == right` failed
 //@ error-pattern:  left: 14
 //@ error-pattern: right: 15
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     assert_eq!(14, 15);

tests/ui/macros/assert-macro-explicit.rs

@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:assertion failed: false
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     assert!(false);

tests/ui/macros/assert-macro-fmt.rs

@@ -1,7 +1,7 @@
 //@ run-fail
 //@ error-pattern: panicked
 //@ error-pattern: test-assert-fmt 42 rust
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     assert!(false, "test-assert-fmt {} {}", 42, "rust");

tests/ui/macros/assert-macro-owned.rs

@@ -1,7 +1,7 @@
 //@ run-fail
 //@ error-pattern:panicked
 //@ error-pattern:test-assert-owned
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 #![allow(non_fmt_panics)]
 

tests/ui/macros/assert-macro-static.rs

@@ -1,7 +1,7 @@
 //@ run-fail
 //@ error-pattern:panicked
 //@ error-pattern:test-assert-static
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     assert!(false, "test-assert-static");

tests/ui/macros/assert-matches-macro-msg.rs

@@ -2,7 +2,7 @@
 //@ error-pattern:assertion `left matches right` failed: 1 + 1 definitely should be 3
 //@ error-pattern:  left: 2
 //@ error-pattern: right: 3
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 #![feature(assert_matches)]
 

tests/ui/macros/assert-ne-macro-msg.rs

@@ -2,7 +2,7 @@
 //@ error-pattern:assertion `left != right` failed: 1 + 1 definitely should not be 2
 //@ error-pattern:  left: 2
 //@ error-pattern: right: 2
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     assert_ne!(1 + 1, 2, "1 + 1 definitely should not be 2");

tests/ui/macros/assert-ne-macro-panic.rs

@@ -2,7 +2,7 @@
 //@ error-pattern:assertion `left != right` failed
 //@ error-pattern:  left: 14
 //@ error-pattern: right: 14
-//@ ignore-emscripten no processes
+//@ needs-subprocess
 
 fn main() {
     assert_ne!(14, 14);