Auto merge of #127360 - GuillaumeGomez:rollup-f0zs1qr, r=GuillaumeGomez

Rollup of 7 pull requests

Successful merges:

 - #124290 (DependencyList: removed outdated comment)
 - #126709 (Migrate `include_bytes_deps`, `optimization-remarks-dir-pgo`, `optimization-remarks-dir`, `issue-40535` and `rmeta-preferred` `run-make` tests to rmake)
 - #127214 (Use the native unwind function in miri where possible)
 - #127320 (Update windows-bindgen to 0.58.0)
 - #127349 (Tweak `-1 as usize` suggestion)
 - #127352 (coverage: Rename `mir::coverage::BranchInfo` to `CoverageInfoHi`)
 - #127359 (Improve run make llvm ident code)

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

Author: bors

compiler/rustc_middle/src/mir/pretty.rs

@@ -473,8 +473,8 @@ pub fn write_mir_intro<'tcx>(
     // Add an empty line before the first block is printed.
     writeln!(w)?;
 
-    if let Some(branch_info) = &body.coverage_branch_info {
-        write_coverage_branch_info(branch_info, w)?;
+    if let Some(coverage_info_hi) = &body.coverage_info_hi {
+        write_coverage_info_hi(coverage_info_hi, w)?;
     }
     if let Some(function_coverage_info) = &body.function_coverage_info {
         write_function_coverage_info(function_coverage_info, w)?;
@@ -483,18 +483,26 @@ pub fn write_mir_intro<'tcx>(
     Ok(())
 }
 
-fn write_coverage_branch_info(
-    branch_info: &coverage::BranchInfo,
+fn write_coverage_info_hi(
+    coverage_info_hi: &coverage::CoverageInfoHi,
     w: &mut dyn io::Write,
 ) -> io::Result<()> {
-    let coverage::BranchInfo { branch_spans, mcdc_branch_spans, mcdc_decision_spans, .. } =
-        branch_info;
+    let coverage::CoverageInfoHi {
+        num_block_markers: _,
+        branch_spans,
+        mcdc_branch_spans,
+        mcdc_decision_spans,
+    } = coverage_info_hi;
+
+    // Only add an extra trailing newline if we printed at least one thing.
+    let mut did_print = false;
 
     for coverage::BranchSpan { span, true_marker, false_marker } in branch_spans {
         writeln!(
             w,
             "{INDENT}coverage branch {{ true: {true_marker:?}, false: {false_marker:?} }} => {span:?}",
         )?;
+        did_print = true;
     }
 
     for coverage::MCDCBranchSpan {
@@ -510,6 +518,7 @@ fn write_coverage_branch_info(
             "{INDENT}coverage mcdc branch {{ condition_id: {:?}, true: {true_marker:?}, false: {false_marker:?}, depth: {decision_depth:?} }} => {span:?}",
             condition_info.map(|info| info.condition_id)
         )?;
+        did_print = true;
     }
 
     for coverage::MCDCDecisionSpan { span, num_conditions, end_markers, decision_depth } in
@@ -519,10 +528,10 @@ fn write_coverage_branch_info(
             w,
             "{INDENT}coverage mcdc decision {{ num_conditions: {num_conditions:?}, end: {end_markers:?}, depth: {decision_depth:?} }} => {span:?}"
         )?;
+        did_print = true;
     }
 
-    if !branch_spans.is_empty() || !mcdc_branch_spans.is_empty() || !mcdc_decision_spans.is_empty()
-    {
+    if did_print {
         writeln!(w)?;
     }
 

compiler/rustc_mir_build/src/build/coverageinfo.rs

@@ -2,7 +2,7 @@ use std::assert_matches::assert_matches;
 use std::collections::hash_map::Entry;
 
 use rustc_data_structures::fx::FxHashMap;
-use rustc_middle::mir::coverage::{BlockMarkerId, BranchSpan, CoverageKind};
+use rustc_middle::mir::coverage::{BlockMarkerId, BranchSpan, CoverageInfoHi, CoverageKind};
 use rustc_middle::mir::{self, BasicBlock, SourceInfo, UnOp};
 use rustc_middle::thir::{ExprId, ExprKind, Pat, Thir};
 use rustc_middle::ty::TyCtxt;
@@ -13,16 +13,25 @@ use crate::build::{Builder, CFG};
 
 mod mcdc;
 
-pub(crate) struct BranchInfoBuilder {
+/// Collects coverage-related information during MIR building, to eventually be
+/// turned into a function's [`CoverageInfoHi`] when MIR building is complete.
+pub(crate) struct CoverageInfoBuilder {
     /// Maps condition expressions to their enclosing `!`, for better instrumentation.
     nots: FxHashMap<ExprId, NotInfo>,
 
     markers: BlockMarkerGen,
-    branch_spans: Vec<BranchSpan>,
 
+    /// Present if branch coverage is enabled.
+    branch_info: Option<BranchInfo>,
+    /// Present if MC/DC coverage is enabled.
     mcdc_info: Option<MCDCInfoBuilder>,
 }
 
+#[derive(Default)]
+struct BranchInfo {
+    branch_spans: Vec<BranchSpan>,
+}
+
 #[derive(Clone, Copy)]
 struct NotInfo {
     /// When visiting the associated expression as a branch condition, treat this
@@ -62,20 +71,20 @@ impl BlockMarkerGen {
     }
 }
 
-impl BranchInfoBuilder {
-    /// Creates a new branch info builder, but only if branch coverage instrumentation
+impl CoverageInfoBuilder {
+    /// Creates a new coverage info builder, but only if coverage instrumentation
     /// is enabled and `def_id` represents a function that is eligible for coverage.
     pub(crate) fn new_if_enabled(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<Self> {
-        if tcx.sess.instrument_coverage_branch() && tcx.is_eligible_for_coverage(def_id) {
-            Some(Self {
-                nots: FxHashMap::default(),
-                markers: BlockMarkerGen::default(),
-                branch_spans: vec![],
-                mcdc_info: tcx.sess.instrument_coverage_mcdc().then(MCDCInfoBuilder::new),
-            })
-        } else {
-            None
+        if !tcx.sess.instrument_coverage() || !tcx.is_eligible_for_coverage(def_id) {
+            return None;
         }
+
+        Some(Self {
+            nots: FxHashMap::default(),
+            markers: BlockMarkerGen::default(),
+            branch_info: tcx.sess.instrument_coverage_branch().then(BranchInfo::default),
+            mcdc_info: tcx.sess.instrument_coverage_mcdc().then(MCDCInfoBuilder::new),
+        })
     }
 
     /// Unary `!` expressions inside an `if` condition are lowered by lowering
@@ -88,6 +97,12 @@ impl BranchInfoBuilder {
     pub(crate) fn visit_unary_not(&mut self, thir: &Thir<'_>, unary_not: ExprId) {
         assert_matches!(thir[unary_not].kind, ExprKind::Unary { op: UnOp::Not, .. });
 
+        // The information collected by this visitor is only needed when branch
+        // coverage or higher is enabled.
+        if self.branch_info.is_none() {
+            return;
+        }
+
         self.visit_with_not_info(
             thir,
             unary_not,
@@ -137,40 +152,40 @@ impl BranchInfoBuilder {
                 false_block,
                 inject_block_marker,
             );
-        } else {
-            let true_marker = self.markers.inject_block_marker(cfg, source_info, true_block);
-            let false_marker = self.markers.inject_block_marker(cfg, source_info, false_block);
-
-            self.branch_spans.push(BranchSpan {
-                span: source_info.span,
-                true_marker,
-                false_marker,
-            });
+            return;
         }
+
+        // Bail out if branch coverage is not enabled.
+        let Some(branch_info) = self.branch_info.as_mut() else { return };
+
+        let true_marker = self.markers.inject_block_marker(cfg, source_info, true_block);
+        let false_marker = self.markers.inject_block_marker(cfg, source_info, false_block);
+
+        branch_info.branch_spans.push(BranchSpan {
+            span: source_info.span,
+            true_marker,
+            false_marker,
+        });
     }
 
-    pub(crate) fn into_done(self) -> Option<Box<mir::coverage::BranchInfo>> {
-        let Self {
-            nots: _,
-            markers: BlockMarkerGen { num_block_markers },
-            branch_spans,
-            mcdc_info,
-        } = self;
+    pub(crate) fn into_done(self) -> Box<CoverageInfoHi> {
+        let Self { nots: _, markers: BlockMarkerGen { num_block_markers }, branch_info, mcdc_info } =
+            self;
 
-        if num_block_markers == 0 {
-            assert!(branch_spans.is_empty());
-            return None;
-        }
+        let branch_spans =
+            branch_info.map(|branch_info| branch_info.branch_spans).unwrap_or_default();
 
         let (mcdc_decision_spans, mcdc_branch_spans) =
             mcdc_info.map(MCDCInfoBuilder::into_done).unwrap_or_default();
 
-        Some(Box::new(mir::coverage::BranchInfo {
+        // For simplicity, always return an info struct (without Option), even
+        // if there's nothing interesting in it.
+        Box::new(CoverageInfoHi {
             num_block_markers,
             branch_spans,
             mcdc_branch_spans,
             mcdc_decision_spans,
-        }))
+        })
     }
 }
 
@@ -184,7 +199,7 @@ impl<'tcx> Builder<'_, 'tcx> {
         block: &mut BasicBlock,
     ) {
         // Bail out if condition coverage is not enabled for this function.
-        let Some(branch_info) = self.coverage_branch_info.as_mut() else { return };
+        let Some(coverage_info) = self.coverage_info.as_mut() else { return };
         if !self.tcx.sess.instrument_coverage_condition() {
             return;
         };
@@ -224,7 +239,7 @@ impl<'tcx> Builder<'_, 'tcx> {
         );
 
         // Separate path for handling branches when MC/DC is enabled.
-        branch_info.register_two_way_branch(
+        coverage_info.register_two_way_branch(
             self.tcx,
             &mut self.cfg,
             source_info,
@@ -247,12 +262,12 @@ impl<'tcx> Builder<'_, 'tcx> {
         mut then_block: BasicBlock,
         mut else_block: BasicBlock,
     ) {
-        // Bail out if branch coverage is not enabled for this function.
-        let Some(branch_info) = self.coverage_branch_info.as_mut() else { return };
+        // Bail out if coverage is not enabled for this function.
+        let Some(coverage_info) = self.coverage_info.as_mut() else { return };
 
         // If this condition expression is nested within one or more `!` expressions,
         // replace it with the enclosing `!` collected by `visit_unary_not`.
-        if let Some(&NotInfo { enclosing_not, is_flipped }) = branch_info.nots.get(&expr_id) {
+        if let Some(&NotInfo { enclosing_not, is_flipped }) = coverage_info.nots.get(&expr_id) {
             expr_id = enclosing_not;
             if is_flipped {
                 std::mem::swap(&mut then_block, &mut else_block);
@@ -261,7 +276,7 @@ impl<'tcx> Builder<'_, 'tcx> {
 
         let source_info = SourceInfo { span: self.thir[expr_id].span, scope: self.source_scope };
 
-        branch_info.register_two_way_branch(
+        coverage_info.register_two_way_branch(
             self.tcx,
             &mut self.cfg,
             source_info,
@@ -280,13 +295,11 @@ impl<'tcx> Builder<'_, 'tcx> {
         true_block: BasicBlock,
         false_block: BasicBlock,
     ) {
-        // Bail out if branch coverage is not enabled for this function.
-        let Some(branch_info) = self.coverage_branch_info.as_mut() else { return };
-
-        // FIXME(#124144) This may need special handling when MC/DC is enabled.
+        // Bail out if coverage is not enabled for this function.
+        let Some(coverage_info) = self.coverage_info.as_mut() else { return };
 
         let source_info = SourceInfo { span: pattern.span, scope: self.source_scope };
-        branch_info.register_two_way_branch(
+        coverage_info.register_two_way_branch(
             self.tcx,
             &mut self.cfg,
             source_info,