Rollup of 12 pull requests

Cargo.lock

@@ -721,6 +721,13 @@ version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9a21fa21941700a3cd8fcb4091f361a6a712fac632f85d9f487cc892045d55c6"
 
+[[package]]
+name = "coverage_test_macros"
+version = "0.0.0"
+dependencies = [
+ "proc-macro2",
+]
+
 [[package]]
 name = "cpuid-bool"
 version = "0.1.2"
@@ -3922,6 +3929,7 @@ dependencies = [
 name = "rustc_mir"
 version = "0.0.0"
 dependencies = [
+ "coverage_test_macros",
  "either",
  "itertools 0.9.0",
  "polonius-engine",

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -2327,11 +2327,12 @@ impl<'a> State<'a> {
             self.print_path(path, false, depth);
         }
         self.s.word(">");
-        self.s.word("::");
-        let item_segment = path.segments.last().unwrap();
-        self.print_ident(item_segment.ident);
-        if let Some(ref args) = item_segment.args {
-            self.print_generic_args(args, colons_before_params)
+        for item_segment in &path.segments[qself.position..] {
+            self.s.word("::");
+            self.print_ident(item_segment.ident);
+            if let Some(ref args) = item_segment.args {
+                self.print_generic_args(args, colons_before_params)
+            }
         }
     }
 

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -925,9 +925,7 @@ unsafe fn embed_bitcode(
         || cgcx.opts.target_triple.triple().starts_with("asmjs")
     {
         // nothing to do here
-    } else if cgcx.opts.target_triple.triple().contains("windows")
-        || cgcx.opts.target_triple.triple().contains("uefi")
-    {
+    } else if cgcx.is_pe_coff {
         let asm = "
             .section .llvmbc,\"n\"
             .section .llvmcmd,\"n\"

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -307,6 +307,7 @@ pub struct CodegenContext<B: WriteBackendMethods> {
     pub allocator_module_config: Arc<ModuleConfig>,
     pub tm_factory: TargetMachineFactory<B>,
     pub msvc_imps_needed: bool,
+    pub is_pe_coff: bool,
     pub target_pointer_width: u32,
     pub target_arch: String,
     pub debuginfo: config::DebugInfo,
@@ -1022,6 +1023,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
         tm_factory: TargetMachineFactory(backend.target_machine_factory(tcx.sess, ol)),
         total_cgus,
         msvc_imps_needed: msvc_imps_needed(tcx),
+        is_pe_coff: tcx.sess.target.is_like_windows,
         target_pointer_width: tcx.sess.target.pointer_width,
         target_arch: tcx.sess.target.arch.clone(),
         debuginfo: tcx.sess.opts.debuginfo,

compiler/rustc_feature/src/active.rs

@@ -616,6 +616,9 @@ declare_features! (
     /// Enables `#[cfg(panic = "...")]` config key.
     (active, cfg_panic, "1.49.0", Some(77443), None),
 
+    /// Allows capturing disjoint fields in a closure/generator (RFC 2229).
+    (active, capture_disjoint_fields, "1.49.0", Some(53488), None),
+
     // -------------------------------------------------------------------------
     // feature-group-end: actual feature gates
     // -------------------------------------------------------------------------
@@ -639,6 +642,7 @@ pub const INCOMPLETE_FEATURES: &[Symbol] = &[
     sym::inline_const,
     sym::repr128,
     sym::unsized_locals,
+    sym::capture_disjoint_fields,
 ];
 
 /// Some features are not allowed to be used together at the same time, if

compiler/rustc_feature/src/builtin_attrs.rs

@@ -547,6 +547,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     // ==========================================================================
 
     rustc_attr!(TEST, rustc_outlives, Normal, template!(Word)),
+    rustc_attr!(TEST, rustc_capture_analysis, Normal, template!(Word)),
     rustc_attr!(TEST, rustc_variance, Normal, template!(Word)),
     rustc_attr!(TEST, rustc_layout, Normal, template!(List: "field1, field2, ...")),
     rustc_attr!(TEST, rustc_regions, Normal, template!(Word)),

compiler/rustc_middle/src/ty/context.rs

@@ -415,6 +415,10 @@ pub struct TypeckResults<'tcx> {
     /// entire variable.
     pub closure_captures: ty::UpvarListMap,
 
+    /// Tracks the minimum captures required for a closure;
+    /// see `MinCaptureInformationMap` for more details.
+    pub closure_min_captures: ty::MinCaptureInformationMap<'tcx>,
+
     /// Stores the type, expression, span and optional scope span of all types
     /// that are live across the yield of this generator (if a generator).
     pub generator_interior_types: Vec<GeneratorInteriorTypeCause<'tcx>>,
@@ -442,6 +446,7 @@ impl<'tcx> TypeckResults<'tcx> {
             tainted_by_errors: None,
             concrete_opaque_types: Default::default(),
             closure_captures: Default::default(),
+            closure_min_captures: Default::default(),
             generator_interior_types: Default::default(),
         }
     }
@@ -676,6 +681,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TypeckResults<'tcx> {
             tainted_by_errors,
             ref concrete_opaque_types,
             ref closure_captures,
+            ref closure_min_captures,
             ref generator_interior_types,
         } = *self;
 
@@ -709,6 +715,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TypeckResults<'tcx> {
             tainted_by_errors.hash_stable(hcx, hasher);
             concrete_opaque_types.hash_stable(hcx, hasher);
             closure_captures.hash_stable(hcx, hasher);
+            closure_min_captures.hash_stable(hcx, hasher);
             generator_interior_types.hash_stable(hcx, hasher);
         })
     }

compiler/rustc_middle/src/ty/mod.rs

@@ -6,6 +6,7 @@ pub use self::IntVarValue::*;
 pub use self::Variance::*;
 
 use crate::hir::exports::ExportMap;
+use crate::hir::place::Place as HirPlace;
 use crate::ich::StableHashingContext;
 use crate::middle::cstore::CrateStoreDyn;
 use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
@@ -611,6 +612,18 @@ pub struct TyS<'tcx> {
     outer_exclusive_binder: ty::DebruijnIndex,
 }
 
+impl<'tcx> TyS<'tcx> {
+    /// A constructor used only for internal testing.
+    #[allow(rustc::usage_of_ty_tykind)]
+    pub fn make_for_test(
+        kind: TyKind<'tcx>,
+        flags: TypeFlags,
+        outer_exclusive_binder: ty::DebruijnIndex,
+    ) -> TyS<'tcx> {
+        TyS { kind, flags, outer_exclusive_binder }
+    }
+}
+
 // `TyS` is used a lot. Make sure it doesn't unintentionally get bigger.
 #[cfg(target_arch = "x86_64")]
 static_assert_size!(TyS<'_>, 32);
@@ -674,6 +687,12 @@ pub struct UpvarId {
     pub closure_expr_id: LocalDefId,
 }
 
+impl UpvarId {
+    pub fn new(var_hir_id: hir::HirId, closure_def_id: LocalDefId) -> UpvarId {
+        UpvarId { var_path: UpvarPath { hir_id: var_hir_id }, closure_expr_id: closure_def_id }
+    }
+}
+
 #[derive(Clone, PartialEq, Debug, TyEncodable, TyDecodable, Copy, HashStable)]
 pub enum BorrowKind {
     /// Data must be immutable and is aliasable.
@@ -756,6 +775,56 @@ pub struct UpvarBorrow<'tcx> {
     pub region: ty::Region<'tcx>,
 }
 
+/// Given the closure DefId this map provides a map of root variables to minimum
+/// set of `CapturedPlace`s that need to be tracked to support all captures of that closure.
+pub type MinCaptureInformationMap<'tcx> = FxHashMap<DefId, RootVariableMinCaptureList<'tcx>>;
+
+/// Part of `MinCaptureInformationMap`; Maps a root variable to the list of `CapturedPlace`.
+/// Used to track the minimum set of `Place`s that need to be captured to support all
+/// Places captured by the closure starting at a given root variable.
+///
+/// This provides a convenient and quick way of checking if a variable being used within
+/// a closure is a capture of a local variable.
+pub type RootVariableMinCaptureList<'tcx> = FxIndexMap<hir::HirId, MinCaptureList<'tcx>>;
+
+/// Part of `MinCaptureInformationMap`; List of `CapturePlace`s.
+pub type MinCaptureList<'tcx> = Vec<CapturedPlace<'tcx>>;
+
+/// A `Place` and the corresponding `CaptureInfo`.
+#[derive(PartialEq, Clone, Debug, TyEncodable, TyDecodable, HashStable)]
+pub struct CapturedPlace<'tcx> {
+    pub place: HirPlace<'tcx>,
+    pub info: CaptureInfo<'tcx>,
+}
+
+/// Part of `MinCaptureInformationMap`; describes the capture kind (&, &mut, move)
+/// for a particular capture as well as identifying the part of the source code
+/// that triggered this capture to occur.
+#[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, HashStable)]
+pub struct CaptureInfo<'tcx> {
+    /// Expr Id pointing to use that resulted in selecting the current capture kind
+    ///
+    /// If the user doesn't enable feature `capture_disjoint_fields` (RFC 2229) then, it is
+    /// possible that we don't see the use of a particular place resulting in expr_id being
+    /// None. In such case we fallback on uvpars_mentioned for span.
+    ///
+    /// Eg:
+    /// ```rust
+    /// let x = ...;
+    ///
+    /// let c = || {
+    ///     let _ = x
+    /// }
+    /// ```
+    ///
+    /// In this example, if `capture_disjoint_fields` is **not** set, then x will be captured,
+    /// but we won't see it being used during capture analysis, since it's essentially a discard.
+    pub expr_id: Option<hir::HirId>,
+
+    /// Capture mode that was selected
+    pub capture_kind: UpvarCapture<'tcx>,
+}
+
 pub type UpvarListMap = FxHashMap<DefId, FxIndexMap<hir::HirId, UpvarId>>;
 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
 

compiler/rustc_mir/Cargo.toml

@@ -31,3 +31,6 @@ rustc_ast = { path = "../rustc_ast" }
 rustc_span = { path = "../rustc_span" }
 rustc_apfloat = { path = "../rustc_apfloat" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
+
+[dev-dependencies]
+coverage_test_macros = { path = "src/transform/coverage/test_macros" }

compiler/rustc_mir/src/borrow_check/diagnostics/mod.rs

@@ -383,16 +383,14 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     self.describe_field_from_ty(&ty, field, variant_index)
                 }
                 ty::Closure(def_id, _) | ty::Generator(def_id, _, _) => {
-                    // `tcx.upvars_mentioned(def_id)` returns an `Option`, which is `None` in case
-                    // the closure comes from another crate. But in that case we wouldn't
-                    // be borrowck'ing it, so we can just unwrap:
-                    let (&var_id, _) = self
-                        .infcx
-                        .tcx
-                        .upvars_mentioned(def_id)
-                        .unwrap()
-                        .get_index(field.index())
-                        .unwrap();
+                    // We won't be borrowck'ing here if the closure came from another crate,
+                    // so it's safe to call `expect_local`.
+                    //
+                    // We know the field exists so it's safe to call operator[] and `unwrap` here.
+                    let (&var_id, _) =
+                        self.infcx.tcx.typeck(def_id.expect_local()).closure_captures[&def_id]
+                            .get_index(field.index())
+                            .unwrap();
 
                     self.infcx.tcx.hir().name(var_id).to_string()
                 }
@@ -967,9 +965,12 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let expr = &self.infcx.tcx.hir().expect_expr(hir_id).kind;
         debug!("closure_span: hir_id={:?} expr={:?}", hir_id, expr);
         if let hir::ExprKind::Closure(.., body_id, args_span, _) = expr {
-            for ((upvar_hir_id, upvar), place) in
-                self.infcx.tcx.upvars_mentioned(def_id)?.iter().zip(places)
+            for (upvar_hir_id, place) in
+                self.infcx.tcx.typeck(def_id.expect_local()).closure_captures[&def_id]
+                    .keys()
+                    .zip(places)
             {
+                let span = self.infcx.tcx.upvars_mentioned(local_did)?[upvar_hir_id].span;
                 match place {
                     Operand::Copy(place) | Operand::Move(place)
                         if target_place == place.as_ref() =>
@@ -991,7 +992,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         let usage_span =
                             match self.infcx.tcx.typeck(local_did).upvar_capture(upvar_id) {
                                 ty::UpvarCapture::ByValue(Some(span)) => span,
-                                _ => upvar.span,
+                                _ => span,
                             };
                         return Some((*args_span, generator_kind, usage_span));
                     }

compiler/rustc_mir/src/transform/coverage/counters.rs

@@ -14,7 +14,7 @@ use rustc_middle::mir::coverage::*;
 
 /// Manages the counter and expression indexes/IDs to generate `CoverageKind` components for MIR
 /// `Coverage` statements.
-pub(crate) struct CoverageCounters {
+pub(super) struct CoverageCounters {
     function_source_hash: u64,
     next_counter_id: u32,
     num_expressions: u32,
@@ -37,7 +37,7 @@ impl CoverageCounters {
         self.debug_counters.enable();
     }
 
-    /// Makes `CoverageKind` `Counter`s and `Expressions` for the `BasicCoverageBlocks` directly or
+    /// Makes `CoverageKind` `Counter`s and `Expressions` for the `BasicCoverageBlock`s directly or
     /// indirectly associated with `CoverageSpans`, and returns additional `Expression`s
     /// representing intermediate values.
     pub fn make_bcb_counters(
@@ -120,7 +120,6 @@ struct BcbCounters<'a> {
     basic_coverage_blocks: &'a mut CoverageGraph,
 }
 
-// FIXME(richkadel): Add unit tests for `BcbCounters` functions/algorithms.
 impl<'a> BcbCounters<'a> {
     fn new(
         coverage_counters: &'a mut CoverageCounters,

compiler/rustc_mir/src/transform/coverage/debug.rs

@@ -127,7 +127,7 @@ pub const NESTED_INDENT: &str = "    ";
 
 const RUSTC_COVERAGE_DEBUG_OPTIONS: &str = "RUSTC_COVERAGE_DEBUG_OPTIONS";
 
-pub(crate) fn debug_options<'a>() -> &'a DebugOptions {
+pub(super) fn debug_options<'a>() -> &'a DebugOptions {
     static DEBUG_OPTIONS: SyncOnceCell<DebugOptions> = SyncOnceCell::new();
 
     &DEBUG_OPTIONS.get_or_init(|| DebugOptions::from_env())
@@ -136,7 +136,7 @@ pub(crate) fn debug_options<'a>() -> &'a DebugOptions {
 /// Parses and maintains coverage-specific debug options captured from the environment variable
 /// "RUSTC_COVERAGE_DEBUG_OPTIONS", if set.
 #[derive(Debug, Clone)]
-pub(crate) struct DebugOptions {
+pub(super) struct DebugOptions {
     pub allow_unused_expressions: bool,
     counter_format: ExpressionFormat,
 }
@@ -250,7 +250,7 @@ impl Default for ExpressionFormat {
 ///
 /// `DebugCounters` supports a recursive rendering of `Expression` counters, so they can be
 /// presented as nested expressions such as `(bcb3 - (bcb0 + bcb1))`.
-pub(crate) struct DebugCounters {
+pub(super) struct DebugCounters {
     some_counters: Option<FxHashMap<ExpressionOperandId, DebugCounter>>,
 }
 
@@ -386,7 +386,7 @@ impl DebugCounter {
 
 /// If enabled, this data structure captures additional debugging information used when generating
 /// a Graphviz (.dot file) representation of the `CoverageGraph`, for debugging purposes.
-pub(crate) struct GraphvizData {
+pub(super) struct GraphvizData {
     some_bcb_to_coverage_spans_with_counters:
         Option<FxHashMap<BasicCoverageBlock, Vec<(CoverageSpan, CoverageKind)>>>,
     some_bcb_to_dependency_counters: Option<FxHashMap<BasicCoverageBlock, Vec<CoverageKind>>>,
@@ -496,7 +496,7 @@ impl GraphvizData {
 /// directly or indirectly, to compute the coverage counts for all `CoverageSpan`s, and any that are
 /// _not_ used are retained in the `unused_expressions` Vec, to be included in debug output (logs
 /// and/or a `CoverageGraph` graphviz output).
-pub(crate) struct UsedExpressions {
+pub(super) struct UsedExpressions {
     some_used_expression_operands:
         Option<FxHashMap<ExpressionOperandId, Vec<InjectedExpressionId>>>,
     some_unused_expressions:
@@ -626,7 +626,7 @@ impl UsedExpressions {
 }
 
 /// Generates the MIR pass `CoverageSpan`-specific spanview dump file.
-pub(crate) fn dump_coverage_spanview(
+pub(super) fn dump_coverage_spanview(
     tcx: TyCtxt<'tcx>,
     mir_body: &mir::Body<'tcx>,
     basic_coverage_blocks: &CoverageGraph,
@@ -666,7 +666,7 @@ fn span_viewables(
 }
 
 /// Generates the MIR pass coverage-specific graphviz dump file.
-pub(crate) fn dump_coverage_graphviz(
+pub(super) fn dump_coverage_graphviz(
     tcx: TyCtxt<'tcx>,
     mir_body: &mir::Body<'tcx>,
     pass_name: &str,
@@ -815,7 +815,7 @@ fn bcb_to_string_sections(
 
 /// Returns a simple string representation of a `TerminatorKind` variant, indenpendent of any
 /// values it might hold.
-pub(crate) fn term_type(kind: &TerminatorKind<'tcx>) -> &'static str {
+pub(super) fn term_type(kind: &TerminatorKind<'tcx>) -> &'static str {
     match kind {
         TerminatorKind::Goto { .. } => "Goto",
         TerminatorKind::SwitchInt { .. } => "SwitchInt",