From 3090b0151c896dd47dedcbd26f1223a534f55f17 Mon Sep 17 00:00:00 2001
From: Tor Hovland <tor.hovland@bekk.no>
Date: Thu, 22 Apr 2021 22:33:54 +0200
Subject: [PATCH 01/12] Use flex more consistently.

---
 src/librustdoc/html/static/rustdoc.css | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index 213ca9ec9e3ea..cf934efbb15d3 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -117,9 +117,12 @@ h4:not(.method):not(.type):not(.tymethod):not(.associatedconstant) {
 }
 h1.fqn {
 	display: flex;
-	width: 100%;
 	border-bottom: 1px dashed;
 	margin-top: 0;
+
+	/* workaround to keep flex from breaking below 700 px width due to the float: right on the nav
+	   above the h1 */
+	padding-left: 1px;
 }
 h1.fqn > .in-band > a:hover {
 	text-decoration: underline;
@@ -453,20 +456,14 @@ nav.sub {
 }
 
 .content .out-of-band {
-	float: right;
+	flex-grow: 0;
+	text-align: right;
 	font-size: 23px;
 	margin: 0px;
-	padding: 0px;
+	padding: 0 0 0 12px;
 	font-weight: normal;
 }
 
-h1.fqn > .out-of-band {
-	float: unset;
-	flex: 1;
-	text-align: right;
-	margin-left: 8px;
-}
-
 h3.impl > .out-of-band {
 	font-size: 21px;
 }
@@ -486,6 +483,7 @@ h4 > code, h3 > code, .invisible > code {
 }
 
 .content .in-band {
+	flex-grow: 1;
 	margin: 0px;
 	padding: 0px;
 }
@@ -1483,10 +1481,6 @@ h4 > .notable-traits {
 		display: none !important;
 	}
 
-	h1.fqn {
-		overflow: initial;
-	}
-
 	.theme-picker {
 		left: 10px;
 		top: 54px;

From aeb67ad870af2abde47b7be81651aa5a3fec6faa Mon Sep 17 00:00:00 2001
From: Rich Kadel <richkadel@google.com>
Date: Mon, 26 Apr 2021 02:45:46 -0700
Subject: [PATCH 02/12] Drop branching blocks with same span as expanded macro

Fixes: #84561
---
 .../rustc_mir/src/transform/coverage/spans.rs |  84 ++++++++++++---
 .../rustc_mir/src/transform/coverage/tests.rs |  13 ++-
 .../expected_show_coverage.issue-84561.txt    | 102 ++++++++++++++++++
 .../run-make-fulldeps/coverage/issue-84561.rs |  94 ++++++++++++++++
 4 files changed, 276 insertions(+), 17 deletions(-)
 create mode 100644 src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt
 create mode 100644 src/test/run-make-fulldeps/coverage/issue-84561.rs

diff --git a/compiler/rustc_mir/src/transform/coverage/spans.rs b/compiler/rustc_mir/src/transform/coverage/spans.rs
index 249f5e835cd78..8dd6f7402fee7 100644
--- a/compiler/rustc_mir/src/transform/coverage/spans.rs
+++ b/compiler/rustc_mir/src/transform/coverage/spans.rs
@@ -11,7 +11,7 @@ use rustc_middle::mir::{
 use rustc_middle::ty::TyCtxt;
 
 use rustc_span::source_map::original_sp;
-use rustc_span::{BytePos, Span};
+use rustc_span::{BytePos, ExpnKind, MacroKind, Span};
 
 use std::cmp::Ordering;
 
@@ -67,6 +67,7 @@ impl CoverageStatement {
 #[derive(Debug, Clone)]
 pub(super) struct CoverageSpan {
     pub span: Span,
+    pub is_macro_expansion: bool,
     pub bcb: BasicCoverageBlock,
     pub coverage_statements: Vec<CoverageStatement>,
     pub is_closure: bool,
@@ -74,12 +75,22 @@ pub(super) struct CoverageSpan {
 
 impl CoverageSpan {
     pub fn for_fn_sig(fn_sig_span: Span) -> Self {
-        Self { span: fn_sig_span, bcb: START_BCB, coverage_statements: vec![], is_closure: false }
+        // Whether the function signature is from a macro or not, it should not be treated like
+        // macro-expanded statements and terminators.
+        let is_macro_expansion = false;
+        Self {
+            span: fn_sig_span,
+            is_macro_expansion,
+            bcb: START_BCB,
+            coverage_statements: vec![],
+            is_closure: false,
+        }
     }
 
     pub fn for_statement(
         statement: &Statement<'tcx>,
         span: Span,
+        is_macro_expansion: bool,
         bcb: BasicCoverageBlock,
         bb: BasicBlock,
         stmt_index: usize,
@@ -94,15 +105,22 @@ impl CoverageSpan {
 
         Self {
             span,
+            is_macro_expansion,
             bcb,
             coverage_statements: vec![CoverageStatement::Statement(bb, span, stmt_index)],
             is_closure,
         }
     }
 
-    pub fn for_terminator(span: Span, bcb: BasicCoverageBlock, bb: BasicBlock) -> Self {
+    pub fn for_terminator(
+        span: Span,
+        is_macro_expansion: bool,
+        bcb: BasicCoverageBlock,
+        bb: BasicBlock,
+    ) -> Self {
         Self {
             span,
+            is_macro_expansion,
             bcb,
             coverage_statements: vec![CoverageStatement::Terminator(bb, span)],
             is_closure: false,
@@ -344,7 +362,27 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
             } else if self.prev_original_span == self.curr().span {
                 // Note that this compares the new span to `prev_original_span`, which may not
                 // be the full `prev.span` (if merged during the previous iteration).
-                self.hold_pending_dups_unless_dominated();
+                if self.prev().is_macro_expansion && self.curr().is_macro_expansion {
+                    // Macros that expand to include branching (such as
+                    // `assert_eq!()`, `assert_ne!()`, `info!()`, `debug!()`, or
+                    // `trace!()) typically generate callee spans with identical
+                    // ranges (typically the full span of the macro) for all
+                    // `BasicBlocks`. This makes it impossible to distinguish
+                    // the condition (`if val1 != val2`) from the optional
+                    // branched statements (such as the call to `panic!()` on
+                    // assert failure). In this case it is better (or less
+                    // worse) to drop the optional branch bcbs and keep the
+                    // non-conditional statements, to count when reached.
+                    debug!(
+                        "  curr and prev are part of a macro expansion, and curr has the same span \
+                        as prev, but is in a different bcb. Drop curr and keep prev for next iter. \
+                        prev={:?}",
+                        self.prev()
+                    );
+                    self.take_curr();
+                } else {
+                    self.hold_pending_dups_unless_dominated();
+                }
             } else {
                 self.cutoff_prev_at_overlapping_curr();
             }
@@ -401,14 +439,24 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
                     .iter()
                     .enumerate()
                     .filter_map(move |(index, statement)| {
-                        filtered_statement_span(statement, self.body_span).map(|span| {
-                            CoverageSpan::for_statement(statement, span, bcb, bb, index)
-                        })
+                        filtered_statement_span(statement, self.body_span).map(
+                            |(span, is_macro_expansion)| {
+                                CoverageSpan::for_statement(
+                                    statement,
+                                    span,
+                                    is_macro_expansion,
+                                    bcb,
+                                    bb,
+                                    index,
+                                )
+                            },
+                        )
                     })
-                    .chain(
-                        filtered_terminator_span(data.terminator(), self.body_span)
-                            .map(|span| CoverageSpan::for_terminator(span, bcb, bb)),
-                    )
+                    .chain(filtered_terminator_span(data.terminator(), self.body_span).map(
+                        |(span, is_macro_expansion)| {
+                            CoverageSpan::for_terminator(span, is_macro_expansion, bcb, bb)
+                        },
+                    ))
             })
             .collect()
     }
@@ -656,7 +704,7 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
 pub(super) fn filtered_statement_span(
     statement: &'a Statement<'tcx>,
     body_span: Span,
-) -> Option<Span> {
+) -> Option<(Span, bool)> {
     match statement.kind {
         // These statements have spans that are often outside the scope of the executed source code
         // for their parent `BasicBlock`.
@@ -701,7 +749,7 @@ pub(super) fn filtered_statement_span(
 pub(super) fn filtered_terminator_span(
     terminator: &'a Terminator<'tcx>,
     body_span: Span,
-) -> Option<Span> {
+) -> Option<(Span, bool)> {
     match terminator.kind {
         // These terminators have spans that don't positively contribute to computing a reasonable
         // span of actually executed source code. (For example, SwitchInt terminators extracted from
@@ -732,7 +780,13 @@ pub(super) fn filtered_terminator_span(
 }
 
 #[inline]
-fn function_source_span(span: Span, body_span: Span) -> Span {
+fn function_source_span(span: Span, body_span: Span) -> (Span, bool) {
+    let is_macro_expansion = span.ctxt() != body_span.ctxt()
+        && if let ExpnKind::Macro(MacroKind::Bang, _) = span.ctxt().outer_expn_data().kind {
+            true
+        } else {
+            false
+        };
     let span = original_sp(span, body_span).with_ctxt(body_span.ctxt());
-    if body_span.contains(span) { span } else { body_span }
+    (if body_span.contains(span) { span } else { body_span }, is_macro_expansion)
 }
diff --git a/compiler/rustc_mir/src/transform/coverage/tests.rs b/compiler/rustc_mir/src/transform/coverage/tests.rs
index dee112443d337..dbbd677fd638d 100644
--- a/compiler/rustc_mir/src/transform/coverage/tests.rs
+++ b/compiler/rustc_mir/src/transform/coverage/tests.rs
@@ -1,6 +1,10 @@
 //! This crate hosts a selection of "unit tests" for components of the `InstrumentCoverage` MIR
 //! pass.
 //!
+//! ```shell
+//! ./x.py test --keep-stage 1 compiler/rustc_mir --test-args '--show-output coverage'
+//! ```
+//!
 //! The tests construct a few "mock" objects, as needed, to support the `InstrumentCoverage`
 //! functions and algorithms. Mocked objects include instances of `mir::Body`; including
 //! `Terminator`s of various `kind`s, and `Span` objects. Some functions used by or used on
@@ -679,10 +683,15 @@ fn test_make_bcb_counters() {
         let mut basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
         let mut coverage_spans = Vec::new();
         for (bcb, data) in basic_coverage_blocks.iter_enumerated() {
-            if let Some(span) =
+            if let Some((span, is_macro_expansion)) =
                 spans::filtered_terminator_span(data.terminator(&mir_body), body_span)
             {
-                coverage_spans.push(spans::CoverageSpan::for_terminator(span, bcb, data.last_bb()));
+                coverage_spans.push(spans::CoverageSpan::for_terminator(
+                    span,
+                    is_macro_expansion,
+                    bcb,
+                    data.last_bb(),
+                ));
             }
         }
         let mut coverage_counters = counters::CoverageCounters::new(0);
diff --git a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt
new file mode 100644
index 0000000000000..34d584f9eae66
--- /dev/null
+++ b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt
@@ -0,0 +1,102 @@
+    1|       |// FIXME(#84561): function-like macros produce unintuitive coverage results.
+    2|       |// This test demonstrates some of the problems.
+    3|       |
+    4|     18|#[derive(Debug, PartialEq, Eq)]
+                       ^5                ^0
+  ------------------
+  | <issue_84561::Foo as core::cmp::PartialEq>::eq:
+  |    4|     18|#[derive(Debug, PartialEq, Eq)]
+  ------------------
+  | Unexecuted instantiation: <issue_84561::Foo as core::cmp::PartialEq>::ne
+  ------------------
+    5|       |struct Foo(u32);
+    6|       |
+    7|      1|fn main() {
+    8|      1|    let bar = Foo(1);
+    9|      1|    assert_eq!(bar, Foo(1));
+   10|      1|    let baz = Foo(0);
+   11|      1|    assert_ne!(baz, Foo(1));
+   12|      1|    println!("{:?}", Foo(1));
+   13|      1|    println!("{:?}", bar);
+   14|      1|    println!("{:?}", baz);
+   15|      1|
+   16|      1|    assert_eq!(Foo(1), Foo(1));
+   17|      1|    assert_ne!(Foo(0), Foo(1));
+   18|      1|    assert_eq!(Foo(2), Foo(2));
+   19|      1|    let bar = Foo(1);
+   20|      1|    assert_ne!(Foo(0), Foo(3));
+   21|      1|    assert_ne!(Foo(0), Foo(4));
+   22|      1|    assert_eq!(Foo(3), Foo(3));
+   23|      1|    assert_ne!(Foo(0), Foo(5));
+   24|      1|    println!("{:?}", bar);
+   25|      1|    println!("{:?}", Foo(1));
+   26|      1|
+   27|      1|    let is_true = std::env::args().len() == 1;
+   28|      1|
+   29|      1|    assert_eq!(
+   30|      1|        Foo(1),
+   31|      1|        Foo(1)
+   32|      1|    );
+   33|      1|    assert_ne!(
+   34|      1|        Foo(0),
+   35|      1|        Foo(1)
+   36|      1|    );
+   37|      1|    assert_eq!(
+   38|      1|        Foo(2),
+   39|      1|        Foo(2)
+   40|      1|    );
+   41|      1|    let bar = Foo(1
+   42|      1|    );
+   43|      1|    assert_ne!(
+   44|      1|        Foo(0),
+   45|      1|        Foo(3)
+   46|      1|    );
+   47|      1|    if is_true {
+   48|      1|        assert_ne!(
+   49|      1|            Foo(0),
+   50|      1|            Foo(4)
+   51|      1|        );
+   52|       |    } else {
+   53|      0|        assert_eq!(
+   54|      0|            Foo(3),
+   55|      0|            Foo(3)
+   56|      0|        );
+   57|       |    }
+   58|       |    assert_ne!(
+   59|      1|        if is_true {
+   60|      1|            Foo(0)
+   61|       |        } else {
+   62|      0|            Foo(1)
+   63|       |        },
+   64|       |        Foo(5)
+   65|       |    );
+   66|      1|    assert_ne!(
+   67|      1|        Foo(5),
+   68|      1|        if is_true {
+   69|      1|            Foo(0)
+   70|       |        } else {
+   71|      0|            Foo(1)
+   72|       |        }
+   73|       |    );
+   74|       |    assert_ne!(
+   75|      1|        if is_true {
+   76|      1|            assert_eq!(
+   77|      1|                Foo(3),
+   78|      1|                Foo(3)
+   79|      1|            );
+   80|      1|            Foo(0)
+   81|       |        } else {
+   82|       |            assert_ne!(
+   83|      0|                if is_true {
+   84|      0|                    Foo(0)
+   85|       |                } else {
+   86|      0|                    Foo(1)
+   87|       |                },
+   88|       |                Foo(5)
+   89|       |            );
+   90|      0|            Foo(1)
+   91|       |        },
+   92|       |        Foo(5)
+   93|       |    );
+   94|      1|}
+
diff --git a/src/test/run-make-fulldeps/coverage/issue-84561.rs b/src/test/run-make-fulldeps/coverage/issue-84561.rs
new file mode 100644
index 0000000000000..a5a0e1dc7581d
--- /dev/null
+++ b/src/test/run-make-fulldeps/coverage/issue-84561.rs
@@ -0,0 +1,94 @@
+// FIXME(#84561): function-like macros produce unintuitive coverage results.
+// This test demonstrates some of the problems.
+
+#[derive(Debug, PartialEq, Eq)]
+struct Foo(u32);
+
+fn main() {
+    let bar = Foo(1);
+    assert_eq!(bar, Foo(1));
+    let baz = Foo(0);
+    assert_ne!(baz, Foo(1));
+    println!("{:?}", Foo(1));
+    println!("{:?}", bar);
+    println!("{:?}", baz);
+
+    assert_eq!(Foo(1), Foo(1));
+    assert_ne!(Foo(0), Foo(1));
+    assert_eq!(Foo(2), Foo(2));
+    let bar = Foo(1);
+    assert_ne!(Foo(0), Foo(3));
+    assert_ne!(Foo(0), Foo(4));
+    assert_eq!(Foo(3), Foo(3));
+    assert_ne!(Foo(0), Foo(5));
+    println!("{:?}", bar);
+    println!("{:?}", Foo(1));
+
+    let is_true = std::env::args().len() == 1;
+
+    assert_eq!(
+        Foo(1),
+        Foo(1)
+    );
+    assert_ne!(
+        Foo(0),
+        Foo(1)
+    );
+    assert_eq!(
+        Foo(2),
+        Foo(2)
+    );
+    let bar = Foo(1
+    );
+    assert_ne!(
+        Foo(0),
+        Foo(3)
+    );
+    if is_true {
+        assert_ne!(
+            Foo(0),
+            Foo(4)
+        );
+    } else {
+        assert_eq!(
+            Foo(3),
+            Foo(3)
+        );
+    }
+    assert_ne!(
+        if is_true {
+            Foo(0)
+        } else {
+            Foo(1)
+        },
+        Foo(5)
+    );
+    assert_ne!(
+        Foo(5),
+        if is_true {
+            Foo(0)
+        } else {
+            Foo(1)
+        }
+    );
+    assert_ne!(
+        if is_true {
+            assert_eq!(
+                Foo(3),
+                Foo(3)
+            );
+            Foo(0)
+        } else {
+            assert_ne!(
+                if is_true {
+                    Foo(0)
+                } else {
+                    Foo(1)
+                },
+                Foo(5)
+            );
+            Foo(1)
+        },
+        Foo(5)
+    );
+}

From 2c4fc3e8f4e3886d1c3b9cb437e428cc4e3d2113 Mon Sep 17 00:00:00 2001
From: Rich Kadel <richkadel@google.com>
Date: Mon, 26 Apr 2021 16:27:54 -0700
Subject: [PATCH 03/12] More improvements to macro coverage

---
 .../rustc_mir/src/transform/coverage/spans.rs | 159 ++++++++----
 .../rustc_mir/src/transform/coverage/tests.rs |   4 +-
 .../expected_show_coverage.inner_items.txt    |   6 +-
 .../expected_show_coverage.issue-84561.txt    | 236 ++++++++++++------
 .../expected_show_coverage.uses_crate.txt     |   6 +-
 ...pected_show_coverage.uses_inline_crate.txt |  12 +-
 .../run-make-fulldeps/coverage/issue-84561.rs |  98 +++++++-
 7 files changed, 366 insertions(+), 155 deletions(-)

diff --git a/compiler/rustc_mir/src/transform/coverage/spans.rs b/compiler/rustc_mir/src/transform/coverage/spans.rs
index 8dd6f7402fee7..97eda1e37e1fa 100644
--- a/compiler/rustc_mir/src/transform/coverage/spans.rs
+++ b/compiler/rustc_mir/src/transform/coverage/spans.rs
@@ -11,7 +11,7 @@ use rustc_middle::mir::{
 use rustc_middle::ty::TyCtxt;
 
 use rustc_span::source_map::original_sp;
-use rustc_span::{BytePos, ExpnKind, MacroKind, Span};
+use rustc_span::{BytePos, ExpnKind, MacroKind, Span, Symbol};
 
 use std::cmp::Ordering;
 
@@ -67,7 +67,7 @@ impl CoverageStatement {
 #[derive(Debug, Clone)]
 pub(super) struct CoverageSpan {
     pub span: Span,
-    pub is_macro_expansion: bool,
+    pub expn_span: Span,
     pub bcb: BasicCoverageBlock,
     pub coverage_statements: Vec<CoverageStatement>,
     pub is_closure: bool,
@@ -75,12 +75,9 @@ pub(super) struct CoverageSpan {
 
 impl CoverageSpan {
     pub fn for_fn_sig(fn_sig_span: Span) -> Self {
-        // Whether the function signature is from a macro or not, it should not be treated like
-        // macro-expanded statements and terminators.
-        let is_macro_expansion = false;
         Self {
             span: fn_sig_span,
-            is_macro_expansion,
+            expn_span: fn_sig_span,
             bcb: START_BCB,
             coverage_statements: vec![],
             is_closure: false,
@@ -90,7 +87,7 @@ impl CoverageSpan {
     pub fn for_statement(
         statement: &Statement<'tcx>,
         span: Span,
-        is_macro_expansion: bool,
+        expn_span: Span,
         bcb: BasicCoverageBlock,
         bb: BasicBlock,
         stmt_index: usize,
@@ -105,7 +102,7 @@ impl CoverageSpan {
 
         Self {
             span,
-            is_macro_expansion,
+            expn_span,
             bcb,
             coverage_statements: vec![CoverageStatement::Statement(bb, span, stmt_index)],
             is_closure,
@@ -114,13 +111,13 @@ impl CoverageSpan {
 
     pub fn for_terminator(
         span: Span,
-        is_macro_expansion: bool,
+        expn_span: Span,
         bcb: BasicCoverageBlock,
         bb: BasicBlock,
     ) -> Self {
         Self {
             span,
-            is_macro_expansion,
+            expn_span,
             bcb,
             coverage_statements: vec![CoverageStatement::Terminator(bb, span)],
             is_closure: false,
@@ -176,6 +173,34 @@ impl CoverageSpan {
             .collect::<Vec<_>>()
             .join("\n")
     }
+
+    /// If the span is part of a macro, and the macro is visible (expands directly to the given
+    /// body_span), returns the macro name symbol.
+    pub fn current_macro(&self) -> Option<Symbol> {
+        if let ExpnKind::Macro(MacroKind::Bang, current_macro) =
+            self.expn_span.ctxt().outer_expn_data().kind
+        {
+            return Some(current_macro);
+        }
+        None
+    }
+
+    /// If the span is part of a macro, and the macro is visible (expands directly to the given
+    /// body_span), returns the macro name symbol.
+    pub fn visible_macro(&self, body_span: Span) -> Option<Symbol> {
+        if let Some(current_macro) = self.current_macro() {
+            if self.expn_span.parent().unwrap_or_else(|| bug!("macro must have a parent")).ctxt()
+                == body_span.ctxt()
+            {
+                return Some(current_macro);
+            }
+        }
+        None
+    }
+
+    pub fn is_macro_expansion(&self) -> bool {
+        self.current_macro().is_some()
+    }
 }
 
 /// Converts the initial set of `CoverageSpan`s (one per MIR `Statement` or `Terminator`) into a
@@ -219,6 +244,9 @@ pub struct CoverageSpans<'a, 'tcx> {
     /// Assigned from `curr_original_span` from the previous iteration.
     prev_original_span: Span,
 
+    /// A copy of the expn_span from the prior iteration.
+    prev_expn_span: Option<Span>,
+
     /// One or more `CoverageSpan`s with the same `Span` but different `BasicCoverageBlock`s, and
     /// no `BasicCoverageBlock` in this list dominates another `BasicCoverageBlock` in the list.
     /// If a new `curr` span also fits this criteria (compared to an existing list of
@@ -273,15 +301,13 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
             curr_original_span: Span::with_root_ctxt(BytePos(0), BytePos(0)),
             some_prev: None,
             prev_original_span: Span::with_root_ctxt(BytePos(0), BytePos(0)),
+            prev_expn_span: None,
             pending_dups: Vec::new(),
         };
 
         let sorted_spans = coverage_spans.mir_to_initial_sorted_coverage_spans();
 
         coverage_spans.sorted_spans_iter = Some(sorted_spans.into_iter());
-        coverage_spans.some_prev = coverage_spans.sorted_spans_iter.as_mut().unwrap().next();
-        coverage_spans.prev_original_span =
-            coverage_spans.some_prev.as_ref().expect("at least one span").span;
 
         coverage_spans.to_refined_spans()
     }
@@ -335,10 +361,14 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
     /// de-duplicated `CoverageSpan`s.
     fn to_refined_spans(mut self) -> Vec<CoverageSpan> {
         while self.next_coverage_span() {
-            if self.curr().is_mergeable(self.prev()) {
+            if self.some_prev.is_none() {
+                debug!("  initial span");
+                self.check_invoked_macro_name_span();
+            } else if self.curr().is_mergeable(self.prev()) {
                 debug!("  same bcb (and neither is a closure), merge with prev={:?}", self.prev());
                 let prev = self.take_prev();
                 self.curr_mut().merge_from(prev);
+                self.check_invoked_macro_name_span();
             // Note that curr.span may now differ from curr_original_span
             } else if self.prev_ends_before_curr() {
                 debug!(
@@ -347,7 +377,8 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
                     self.prev()
                 );
                 let prev = self.take_prev();
-                self.refined_spans.push(prev);
+                self.push_refined_span(prev);
+                self.check_invoked_macro_name_span();
             } else if self.prev().is_closure {
                 // drop any equal or overlapping span (`curr`) and keep `prev` to test again in the
                 // next iter
@@ -362,7 +393,7 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
             } else if self.prev_original_span == self.curr().span {
                 // Note that this compares the new span to `prev_original_span`, which may not
                 // be the full `prev.span` (if merged during the previous iteration).
-                if self.prev().is_macro_expansion && self.curr().is_macro_expansion {
+                if self.prev().is_macro_expansion() && self.curr().is_macro_expansion() {
                     // Macros that expand to include branching (such as
                     // `assert_eq!()`, `assert_ne!()`, `info!()`, `debug!()`, or
                     // `trace!()) typically generate callee spans with identical
@@ -385,15 +416,16 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
                 }
             } else {
                 self.cutoff_prev_at_overlapping_curr();
+                self.check_invoked_macro_name_span();
             }
         }
 
         debug!("    AT END, adding last prev={:?}", self.prev());
         let prev = self.take_prev();
-        let CoverageSpans { pending_dups, mut refined_spans, .. } = self;
+        let pending_dups = self.pending_dups.split_off(0);
         for dup in pending_dups {
             debug!("    ...adding at least one pending dup={:?}", dup);
-            refined_spans.push(dup);
+            self.push_refined_span(dup);
         }
 
         // Async functions wrap a closure that implements the body to be executed. The enclosing
@@ -403,21 +435,60 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
         // excluded. The closure's `Return` is the only one that will be counted. This provides
         // adequate coverage, and more intuitive counts. (Avoids double-counting the closing brace
         // of the function body.)
-        let body_ends_with_closure = if let Some(last_covspan) = refined_spans.last() {
+        let body_ends_with_closure = if let Some(last_covspan) = self.refined_spans.last() {
             last_covspan.is_closure && last_covspan.span.hi() == self.body_span.hi()
         } else {
             false
         };
 
         if !body_ends_with_closure {
-            refined_spans.push(prev);
+            self.push_refined_span(prev);
         }
 
         // Remove `CoverageSpan`s derived from closures, originally added to ensure the coverage
         // regions for the current function leave room for the closure's own coverage regions
         // (injected separately, from the closure's own MIR).
-        refined_spans.retain(|covspan| !covspan.is_closure);
-        refined_spans
+        self.refined_spans.retain(|covspan| !covspan.is_closure);
+        self.refined_spans
+    }
+
+    fn push_refined_span(&mut self, covspan: CoverageSpan) {
+        let len = self.refined_spans.len();
+        if len > 0 {
+            let last = &mut self.refined_spans[len - 1];
+            if last.is_mergeable(&covspan) {
+                debug!(
+                    "merging new refined span with last refined span, last={:?}, covspan={:?}",
+                    last, covspan
+                );
+                last.merge_from(covspan);
+                return;
+            }
+        }
+        self.refined_spans.push(covspan)
+    }
+
+    fn check_invoked_macro_name_span(&mut self) {
+        if let Some(visible_macro) = self.curr().visible_macro(self.body_span) {
+            if self.prev_expn_span.map_or(true, |prev_expn_span| {
+                self.curr().expn_span.ctxt() != prev_expn_span.ctxt()
+            }) {
+                let merged_prefix_len = self.curr_original_span.lo() - self.curr().span.lo();
+                let after_macro_bang = merged_prefix_len
+                    + BytePos(visible_macro.to_string().bytes().count() as u32 + 1);
+                let mut macro_name_cov = self.curr().clone();
+                self.curr_mut().span =
+                    self.curr().span.with_lo(self.curr().span.lo() + after_macro_bang);
+                macro_name_cov.span =
+                    macro_name_cov.span.with_hi(macro_name_cov.span.lo() + after_macro_bang);
+                debug!(
+                    "  and curr starts a new macro expansion, so add a new span just for \
+                            the macro `{}!`, new span={:?}",
+                    visible_macro, macro_name_cov
+                );
+                self.push_refined_span(macro_name_cov);
+            }
+        }
     }
 
     // Generate a set of `CoverageSpan`s from the filtered set of `Statement`s and `Terminator`s of
@@ -440,22 +511,15 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
                     .enumerate()
                     .filter_map(move |(index, statement)| {
                         filtered_statement_span(statement, self.body_span).map(
-                            |(span, is_macro_expansion)| {
+                            |(span, expn_span)| {
                                 CoverageSpan::for_statement(
-                                    statement,
-                                    span,
-                                    is_macro_expansion,
-                                    bcb,
-                                    bb,
-                                    index,
+                                    statement, span, expn_span, bcb, bb, index,
                                 )
                             },
                         )
                     })
                     .chain(filtered_terminator_span(data.terminator(), self.body_span).map(
-                        |(span, is_macro_expansion)| {
-                            CoverageSpan::for_terminator(span, is_macro_expansion, bcb, bb)
-                        },
+                        |(span, expn_span)| CoverageSpan::for_terminator(span, expn_span, bcb, bb),
                     ))
             })
             .collect()
@@ -509,7 +573,7 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
                     let pending_dups = self.pending_dups.split_off(0);
                     for dup in pending_dups.into_iter() {
                         debug!("    ...adding at least one pending={:?}", dup);
-                        self.refined_spans.push(dup);
+                        self.push_refined_span(dup);
                     }
                 } else {
                     self.pending_dups.clear();
@@ -521,12 +585,13 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
     /// Advance `prev` to `curr` (if any), and `curr` to the next `CoverageSpan` in sorted order.
     fn next_coverage_span(&mut self) -> bool {
         if let Some(curr) = self.some_curr.take() {
+            self.prev_expn_span = Some(curr.expn_span);
             self.some_prev = Some(curr);
             self.prev_original_span = self.curr_original_span;
         }
         while let Some(curr) = self.sorted_spans_iter.as_mut().unwrap().next() {
             debug!("FOR curr={:?}", curr);
-            if self.prev_starts_after_next(&curr) {
+            if self.some_prev.is_some() && self.prev_starts_after_next(&curr) {
                 debug!(
                     "  prev.span starts after curr.span, so curr will be dropped (skipping past \
                     closure?); prev={:?}",
@@ -583,10 +648,10 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
                 for mut dup in pending_dups.iter().cloned() {
                     dup.span = dup.span.with_hi(left_cutoff);
                     debug!("    ...and at least one pre_closure dup={:?}", dup);
-                    self.refined_spans.push(dup);
+                    self.push_refined_span(dup);
                 }
             }
-            self.refined_spans.push(pre_closure);
+            self.push_refined_span(pre_closure);
         }
         if has_post_closure_span {
             // Update prev.span to start after the closure (and discard curr)
@@ -597,7 +662,7 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
             }
             self.pending_dups.append(&mut pending_dups);
             let closure_covspan = self.take_curr();
-            self.refined_spans.push(closure_covspan); // since self.prev() was already updated
+            self.push_refined_span(closure_covspan); // since self.prev() was already updated
         } else {
             pending_dups.clear();
         }
@@ -688,7 +753,7 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
             } else {
                 debug!("  ... adding modified prev={:?}", self.prev());
                 let prev = self.take_prev();
-                self.refined_spans.push(prev);
+                self.push_refined_span(prev);
             }
         } else {
             // with `pending_dups`, `prev` cannot have any statements that don't overlap
@@ -704,7 +769,7 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
 pub(super) fn filtered_statement_span(
     statement: &'a Statement<'tcx>,
     body_span: Span,
-) -> Option<(Span, bool)> {
+) -> Option<(Span, Span)> {
     match statement.kind {
         // These statements have spans that are often outside the scope of the executed source code
         // for their parent `BasicBlock`.
@@ -749,7 +814,7 @@ pub(super) fn filtered_statement_span(
 pub(super) fn filtered_terminator_span(
     terminator: &'a Terminator<'tcx>,
     body_span: Span,
-) -> Option<(Span, bool)> {
+) -> Option<(Span, Span)> {
     match terminator.kind {
         // These terminators have spans that don't positively contribute to computing a reasonable
         // span of actually executed source code. (For example, SwitchInt terminators extracted from
@@ -779,14 +844,10 @@ pub(super) fn filtered_terminator_span(
     }
 }
 
+/// Returns the span within the function source body, and the given span, which will be different
+/// if the given span is an expansion (macro, syntactic sugar, etc.).
 #[inline]
-fn function_source_span(span: Span, body_span: Span) -> (Span, bool) {
-    let is_macro_expansion = span.ctxt() != body_span.ctxt()
-        && if let ExpnKind::Macro(MacroKind::Bang, _) = span.ctxt().outer_expn_data().kind {
-            true
-        } else {
-            false
-        };
-    let span = original_sp(span, body_span).with_ctxt(body_span.ctxt());
-    (if body_span.contains(span) { span } else { body_span }, is_macro_expansion)
+fn function_source_span(span: Span, body_span: Span) -> (Span, Span) {
+    let original_span = original_sp(span, body_span).with_ctxt(body_span.ctxt());
+    (if body_span.contains(original_span) { original_span } else { body_span }, span)
 }
diff --git a/compiler/rustc_mir/src/transform/coverage/tests.rs b/compiler/rustc_mir/src/transform/coverage/tests.rs
index dbbd677fd638d..9b84173c8a293 100644
--- a/compiler/rustc_mir/src/transform/coverage/tests.rs
+++ b/compiler/rustc_mir/src/transform/coverage/tests.rs
@@ -683,12 +683,12 @@ fn test_make_bcb_counters() {
         let mut basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
         let mut coverage_spans = Vec::new();
         for (bcb, data) in basic_coverage_blocks.iter_enumerated() {
-            if let Some((span, is_macro_expansion)) =
+            if let Some((span, expn_span)) =
                 spans::filtered_terminator_span(data.terminator(&mir_body), body_span)
             {
                 coverage_spans.push(spans::CoverageSpan::for_terminator(
                     span,
-                    is_macro_expansion,
+                    expn_span,
                     bcb,
                     data.last_bb(),
                 ));
diff --git a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.inner_items.txt b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.inner_items.txt
index f5b5184044f65..883254a09ba7d 100644
--- a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.inner_items.txt
+++ b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.inner_items.txt
@@ -1,9 +1,9 @@
     1|       |#![allow(unused_assignments, unused_variables, dead_code)]
     2|       |
     3|      1|fn main() {
-    4|       |    // Initialize test constants in a way that cannot be determined at compile time, to ensure
-    5|       |    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
-    6|       |    // dependent conditions.
+    4|      1|    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    5|      1|    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    6|      1|    // dependent conditions.
     7|      1|    let is_true = std::env::args().len() == 1;
     8|      1|
     9|      1|    let mut countdown = 0;
diff --git a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt
index 34d584f9eae66..5d266b5db15f2 100644
--- a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt
+++ b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt
@@ -1,17 +1,17 @@
-    1|       |// FIXME(#84561): function-like macros produce unintuitive coverage results.
-    2|       |// This test demonstrates some of the problems.
-    3|       |
-    4|     18|#[derive(Debug, PartialEq, Eq)]
-                       ^5                ^0
+    1|       |// This demonstrated Issue #84561: function-like macros produce unintuitive coverage results.
+    2|       |
+    3|       |// expect-exit-status-101
+    4|     21|#[derive(PartialEq, Eq)]
+                                  ^0
   ------------------
   | <issue_84561::Foo as core::cmp::PartialEq>::eq:
-  |    4|     18|#[derive(Debug, PartialEq, Eq)]
+  |    4|     21|#[derive(PartialEq, Eq)]
   ------------------
   | Unexecuted instantiation: <issue_84561::Foo as core::cmp::PartialEq>::ne
   ------------------
     5|       |struct Foo(u32);
-    6|       |
-    7|      1|fn main() {
+    6|      1|fn test2() {
+    7|      1|    let is_true = std::env::args().len() == 1;
     8|      1|    let bar = Foo(1);
     9|      1|    assert_eq!(bar, Foo(1));
    10|      1|    let baz = Foo(0);
@@ -23,80 +23,158 @@
    16|      1|    assert_eq!(Foo(1), Foo(1));
    17|      1|    assert_ne!(Foo(0), Foo(1));
    18|      1|    assert_eq!(Foo(2), Foo(2));
-   19|      1|    let bar = Foo(1);
-   20|      1|    assert_ne!(Foo(0), Foo(3));
+   19|      1|    let bar = Foo(0);
+   20|      1|    assert_ne!(bar, Foo(3));
    21|      1|    assert_ne!(Foo(0), Foo(4));
-   22|      1|    assert_eq!(Foo(3), Foo(3));
-   23|      1|    assert_ne!(Foo(0), Foo(5));
-   24|      1|    println!("{:?}", bar);
-   25|      1|    println!("{:?}", Foo(1));
-   26|      1|
-   27|      1|    let is_true = std::env::args().len() == 1;
-   28|      1|
-   29|      1|    assert_eq!(
-   30|      1|        Foo(1),
-   31|      1|        Foo(1)
-   32|      1|    );
-   33|      1|    assert_ne!(
-   34|      1|        Foo(0),
-   35|      1|        Foo(1)
-   36|      1|    );
-   37|      1|    assert_eq!(
-   38|      1|        Foo(2),
-   39|      1|        Foo(2)
-   40|      1|    );
-   41|      1|    let bar = Foo(1
-   42|      1|    );
-   43|      1|    assert_ne!(
-   44|      1|        Foo(0),
-   45|      1|        Foo(3)
-   46|      1|    );
-   47|      1|    if is_true {
-   48|      1|        assert_ne!(
-   49|      1|            Foo(0),
-   50|      1|            Foo(4)
-   51|      1|        );
-   52|       |    } else {
-   53|      0|        assert_eq!(
-   54|      0|            Foo(3),
-   55|      0|            Foo(3)
-   56|      0|        );
-   57|       |    }
-   58|       |    assert_ne!(
-   59|      1|        if is_true {
-   60|      1|            Foo(0)
-   61|       |        } else {
-   62|      0|            Foo(1)
-   63|       |        },
-   64|       |        Foo(5)
-   65|       |    );
-   66|      1|    assert_ne!(
-   67|      1|        Foo(5),
-   68|      1|        if is_true {
-   69|      1|            Foo(0)
-   70|       |        } else {
-   71|      0|            Foo(1)
-   72|       |        }
-   73|       |    );
-   74|       |    assert_ne!(
-   75|      1|        if is_true {
-   76|      1|            assert_eq!(
-   77|      1|                Foo(3),
-   78|      1|                Foo(3)
-   79|      1|            );
-   80|      1|            Foo(0)
-   81|       |        } else {
-   82|       |            assert_ne!(
-   83|      0|                if is_true {
-   84|      0|                    Foo(0)
-   85|       |                } else {
-   86|      0|                    Foo(1)
-   87|       |                },
-   88|       |                Foo(5)
-   89|       |            );
+   22|      1|    assert_eq!(Foo(3), Foo(3), "with a message");
+                                             ^0
+   23|      1|    println!("{:?}", bar);
+   24|      1|    println!("{:?}", Foo(1));
+   25|      1|
+   26|      1|    assert_ne!(Foo(0), Foo(5), "{}", if is_true { "true message" } else { "false message" });
+                                             ^0                 ^0                      ^0
+   27|      1|    assert_ne!(
+   28|       |        Foo(0)
+   29|       |        ,
+   30|       |        Foo(5)
+   31|       |        ,
+   32|      0|        "{}"
+   33|      0|        ,
+   34|      0|        if
+   35|      0|        is_true
+   36|       |        {
+   37|      0|            "true message"
+   38|       |        } else {
+   39|      0|            "false message"
+   40|       |        }
+   41|       |    );
+   42|       |
+   43|      1|    let is_true = std::env::args().len() == 1;
+   44|      1|
+   45|      1|    assert_eq!(
+   46|      1|        Foo(1),
+   47|      1|        Foo(1)
+   48|      1|    );
+   49|      1|    assert_ne!(
+   50|      1|        Foo(0),
+   51|      1|        Foo(1)
+   52|      1|    );
+   53|      1|    assert_eq!(
+   54|      1|        Foo(2),
+   55|      1|        Foo(2)
+   56|      1|    );
+   57|      1|    let bar = Foo(1);
+   58|      1|    assert_ne!(
+   59|      1|        bar,
+   60|      1|        Foo(3)
+   61|      1|    );
+   62|      1|    if is_true {
+   63|      1|        assert_ne!(
+   64|      1|            Foo(0),
+   65|      1|            Foo(4)
+   66|      1|        );
+   67|       |    } else {
+   68|      0|        assert_eq!(
+   69|      0|            Foo(3),
+   70|      0|            Foo(3)
+   71|      0|        );
+   72|       |    }
+   73|      1|    if is_true {
+   74|      1|        assert_ne!(
+   75|       |            Foo(0),
+   76|       |            Foo(4),
+   77|      0|            "with a message"
+   78|       |        );
+   79|       |    } else {
+   80|      0|        assert_eq!(
+   81|       |            Foo(3),
+   82|       |            Foo(3),
+   83|      0|            "with a message"
+   84|       |        );
+   85|       |    }
+   86|      1|    assert_ne!(
+   87|      1|        if is_true {
+   88|      1|            Foo(0)
+   89|       |        } else {
    90|      0|            Foo(1)
    91|       |        },
    92|       |        Foo(5)
    93|       |    );
-   94|      1|}
+   94|      1|    assert_ne!(
+   95|      1|        Foo(5),
+   96|      1|        if is_true {
+   97|      1|            Foo(0)
+   98|       |        } else {
+   99|      0|            Foo(1)
+  100|       |        }
+  101|       |    );
+  102|      1|    assert_ne!(
+  103|      1|        if is_true {
+  104|      1|            assert_eq!(
+  105|      1|                Foo(3),
+  106|      1|                Foo(3)
+  107|      1|            );
+  108|      1|            Foo(0)
+  109|       |        } else {
+  110|      0|            assert_ne!(
+  111|      0|                if is_true {
+  112|      0|                    Foo(0)
+  113|       |                } else {
+  114|      0|                    Foo(1)
+  115|       |                },
+  116|       |                Foo(5)
+  117|       |            );
+  118|      0|            Foo(1)
+  119|       |        },
+  120|       |        Foo(5),
+  121|      0|        "with a message"
+  122|       |    );
+  123|      1|    assert_eq!(
+  124|       |        Foo(1),
+  125|       |        Foo(3),
+  126|      1|        "this assert should fail"
+  127|       |    );
+  128|      0|    assert_eq!(
+  129|       |        Foo(3),
+  130|       |        Foo(3),
+  131|      0|        "this assert should not be reached"
+  132|       |    );
+  133|      0|}
+  134|       |
+  135|       |impl std::fmt::Debug for Foo {
+  136|       |    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+  137|      7|        write!(f, "try and succeed")?;
+                                                  ^0
+  138|      7|        Ok(())
+  139|      7|    }
+  140|       |}
+  141|       |
+  142|       |static mut DEBUG_LEVEL_ENABLED: bool = false;
+  143|       |
+  144|       |macro_rules! debug {
+  145|       |    ($($arg:tt)+) => (
+  146|       |        if unsafe { DEBUG_LEVEL_ENABLED } {
+  147|       |            println!($($arg)+);
+  148|       |        }
+  149|       |    );
+  150|       |}
+  151|       |
+  152|      1|fn test1() {
+  153|      1|    debug!("debug is enabled");
+                         ^0
+  154|      1|    debug!("debug is enabled");
+                         ^0
+  155|      1|    let _ = 0;
+  156|      1|    debug!("debug is enabled");
+                         ^0
+  157|      1|    unsafe {
+  158|      1|        DEBUG_LEVEL_ENABLED = true;
+  159|      1|    }
+  160|      1|    debug!("debug is enabled");
+  161|      1|}
+  162|       |
+  163|      1|fn main() {
+  164|      1|    test1();
+  165|      1|    test2();
+  166|      1|}
 
diff --git a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.uses_crate.txt b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.uses_crate.txt
index f5beb9ef24a0e..c2d5143a61816 100644
--- a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.uses_crate.txt
+++ b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.uses_crate.txt
@@ -3,9 +3,9 @@
     3|       |use std::fmt::Debug;
     4|       |
     5|      1|pub fn used_function() {
-    6|       |    // Initialize test constants in a way that cannot be determined at compile time, to ensure
-    7|       |    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
-    8|       |    // dependent conditions.
+    6|      1|    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    7|      1|    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+    8|      1|    // dependent conditions.
     9|      1|    let is_true = std::env::args().len() == 1;
    10|      1|    let mut countdown = 0;
    11|      1|    if is_true {
diff --git a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.uses_inline_crate.txt b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.uses_inline_crate.txt
index cc98956e3073a..dab31cbf4ac9e 100644
--- a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.uses_inline_crate.txt
+++ b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.uses_inline_crate.txt
@@ -5,9 +5,9 @@
     5|       |use std::fmt::Debug;
     6|       |
     7|      1|pub fn used_function() {
-    8|       |    // Initialize test constants in a way that cannot be determined at compile time, to ensure
-    9|       |    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
-   10|       |    // dependent conditions.
+    8|      1|    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+    9|      1|    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+   10|      1|    // dependent conditions.
    11|      1|    let is_true = std::env::args().len() == 1;
    12|      1|    let mut countdown = 0;
    13|      1|    if is_true {
@@ -19,9 +19,9 @@
    18|       |
    19|       |#[inline(always)]
    20|      1|pub fn used_inline_function() {
-   21|       |    // Initialize test constants in a way that cannot be determined at compile time, to ensure
-   22|       |    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
-   23|       |    // dependent conditions.
+   21|      1|    // Initialize test constants in a way that cannot be determined at compile time, to ensure
+   22|      1|    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
+   23|      1|    // dependent conditions.
    24|      1|    let is_true = std::env::args().len() == 1;
    25|      1|    let mut countdown = 0;
    26|      1|    if is_true {
diff --git a/src/test/run-make-fulldeps/coverage/issue-84561.rs b/src/test/run-make-fulldeps/coverage/issue-84561.rs
index a5a0e1dc7581d..5c8fd0b7caeaa 100644
--- a/src/test/run-make-fulldeps/coverage/issue-84561.rs
+++ b/src/test/run-make-fulldeps/coverage/issue-84561.rs
@@ -1,10 +1,10 @@
-// FIXME(#84561): function-like macros produce unintuitive coverage results.
-// This test demonstrates some of the problems.
+// This demonstrated Issue #84561: function-like macros produce unintuitive coverage results.
 
-#[derive(Debug, PartialEq, Eq)]
+// expect-exit-status-101
+#[derive(PartialEq, Eq)]
 struct Foo(u32);
-
-fn main() {
+fn test2() {
+    let is_true = std::env::args().len() == 1;
     let bar = Foo(1);
     assert_eq!(bar, Foo(1));
     let baz = Foo(0);
@@ -16,14 +16,30 @@ fn main() {
     assert_eq!(Foo(1), Foo(1));
     assert_ne!(Foo(0), Foo(1));
     assert_eq!(Foo(2), Foo(2));
-    let bar = Foo(1);
-    assert_ne!(Foo(0), Foo(3));
+    let bar = Foo(0);
+    assert_ne!(bar, Foo(3));
     assert_ne!(Foo(0), Foo(4));
-    assert_eq!(Foo(3), Foo(3));
-    assert_ne!(Foo(0), Foo(5));
+    assert_eq!(Foo(3), Foo(3), "with a message");
     println!("{:?}", bar);
     println!("{:?}", Foo(1));
 
+    assert_ne!(Foo(0), Foo(5), "{}", if is_true { "true message" } else { "false message" });
+    assert_ne!(
+        Foo(0)
+        ,
+        Foo(5)
+        ,
+        "{}"
+        ,
+        if
+        is_true
+        {
+            "true message"
+        } else {
+            "false message"
+        }
+    );
+
     let is_true = std::env::args().len() == 1;
 
     assert_eq!(
@@ -38,10 +54,9 @@ fn main() {
         Foo(2),
         Foo(2)
     );
-    let bar = Foo(1
-    );
+    let bar = Foo(1);
     assert_ne!(
-        Foo(0),
+        bar,
         Foo(3)
     );
     if is_true {
@@ -55,6 +70,19 @@ fn main() {
             Foo(3)
         );
     }
+    if is_true {
+        assert_ne!(
+            Foo(0),
+            Foo(4),
+            "with a message"
+        );
+    } else {
+        assert_eq!(
+            Foo(3),
+            Foo(3),
+            "with a message"
+        );
+    }
     assert_ne!(
         if is_true {
             Foo(0)
@@ -89,6 +117,50 @@ fn main() {
             );
             Foo(1)
         },
-        Foo(5)
+        Foo(5),
+        "with a message"
+    );
+    assert_eq!(
+        Foo(1),
+        Foo(3),
+        "this assert should fail"
+    );
+    assert_eq!(
+        Foo(3),
+        Foo(3),
+        "this assert should not be reached"
+    );
+}
+
+impl std::fmt::Debug for Foo {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(f, "try and succeed")?;
+        Ok(())
+    }
+}
+
+static mut DEBUG_LEVEL_ENABLED: bool = false;
+
+macro_rules! debug {
+    ($($arg:tt)+) => (
+        if unsafe { DEBUG_LEVEL_ENABLED } {
+            println!($($arg)+);
+        }
     );
 }
+
+fn test1() {
+    debug!("debug is enabled");
+    debug!("debug is enabled");
+    let _ = 0;
+    debug!("debug is enabled");
+    unsafe {
+        DEBUG_LEVEL_ENABLED = true;
+    }
+    debug!("debug is enabled");
+}
+
+fn main() {
+    test1();
+    test2();
+}

From bbf6bcee80dcfb566b4d975ff6c3476c0864352e Mon Sep 17 00:00:00 2001
From: Rich Kadel <richkadel@google.com>
Date: Sat, 24 Apr 2021 17:22:29 -0700
Subject: [PATCH 04/12] spanview debug output caused ICE when a function had no
 body

---
 compiler/rustc_mir/src/util/spanview.rs | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/compiler/rustc_mir/src/util/spanview.rs b/compiler/rustc_mir/src/util/spanview.rs
index a9a30e407b4b0..9abfa4a8dc68b 100644
--- a/compiler/rustc_mir/src/util/spanview.rs
+++ b/compiler/rustc_mir/src/util/spanview.rs
@@ -99,7 +99,11 @@ where
     W: Write,
 {
     let def_id = body.source.def_id();
-    let body_span = hir_body(tcx, def_id).value.span;
+    let hir_body = hir_body(tcx, def_id);
+    if hir_body.is_none() {
+        return Ok(());
+    }
+    let body_span = hir_body.unwrap().value.span;
     let mut span_viewables = Vec::new();
     for (bb, data) in body.basic_blocks().iter_enumerated() {
         match spanview {
@@ -664,19 +668,16 @@ fn fn_span<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Span {
     let hir_id =
         tcx.hir().local_def_id_to_hir_id(def_id.as_local().expect("expected DefId is local"));
     let fn_decl_span = tcx.hir().span(hir_id);
-    let body_span = hir_body(tcx, def_id).value.span;
-    if fn_decl_span.ctxt() == body_span.ctxt() {
-        fn_decl_span.to(body_span)
+    if let Some(body_span) = hir_body(tcx, def_id).map(|hir_body| hir_body.value.span) {
+        if fn_decl_span.ctxt() == body_span.ctxt() { fn_decl_span.to(body_span) } else { body_span }
     } else {
-        // This probably occurs for functions defined via macros
-        body_span
+        fn_decl_span
     }
 }
 
-fn hir_body<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx rustc_hir::Body<'tcx> {
+fn hir_body<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Option<&'tcx rustc_hir::Body<'tcx>> {
     let hir_node = tcx.hir().get_if_local(def_id).expect("expected DefId is local");
-    let fn_body_id = hir::map::associated_body(hir_node).expect("HIR node is a function with body");
-    tcx.hir().body(fn_body_id)
+    hir::map::associated_body(hir_node).map(|fn_body_id| tcx.hir().body(fn_body_id))
 }
 
 fn escape_html(s: &str) -> String {

From fd85fd308b536bd42073f58636358ca147822947 Mon Sep 17 00:00:00 2001
From: Rich Kadel <richkadel@google.com>
Date: Tue, 27 Apr 2021 21:45:30 -0700
Subject: [PATCH 05/12] addressed review feedback

---
 .../rustc_mir/src/transform/coverage/spans.rs | 52 ++++++++++++++-----
 .../expected_show_coverage.issue-84561.txt    | 26 ++++++++--
 .../run-make-fulldeps/coverage/issue-84561.rs | 18 ++++++-
 3 files changed, 78 insertions(+), 18 deletions(-)

diff --git a/compiler/rustc_mir/src/transform/coverage/spans.rs b/compiler/rustc_mir/src/transform/coverage/spans.rs
index 97eda1e37e1fa..ed373f03b5a55 100644
--- a/compiler/rustc_mir/src/transform/coverage/spans.rs
+++ b/compiler/rustc_mir/src/transform/coverage/spans.rs
@@ -13,6 +13,7 @@ use rustc_middle::ty::TyCtxt;
 use rustc_span::source_map::original_sp;
 use rustc_span::{BytePos, ExpnKind, MacroKind, Span, Symbol};
 
+use std::cell::RefCell;
 use std::cmp::Ordering;
 
 #[derive(Debug, Copy, Clone)]
@@ -68,6 +69,7 @@ impl CoverageStatement {
 pub(super) struct CoverageSpan {
     pub span: Span,
     pub expn_span: Span,
+    pub current_macro_or_none: RefCell<Option<Option<Symbol>>>,
     pub bcb: BasicCoverageBlock,
     pub coverage_statements: Vec<CoverageStatement>,
     pub is_closure: bool,
@@ -78,6 +80,7 @@ impl CoverageSpan {
         Self {
             span: fn_sig_span,
             expn_span: fn_sig_span,
+            current_macro_or_none: Default::default(),
             bcb: START_BCB,
             coverage_statements: vec![],
             is_closure: false,
@@ -103,6 +106,7 @@ impl CoverageSpan {
         Self {
             span,
             expn_span,
+            current_macro_or_none: Default::default(),
             bcb,
             coverage_statements: vec![CoverageStatement::Statement(bb, span, stmt_index)],
             is_closure,
@@ -118,6 +122,7 @@ impl CoverageSpan {
         Self {
             span,
             expn_span,
+            current_macro_or_none: Default::default(),
             bcb,
             coverage_statements: vec![CoverageStatement::Terminator(bb, span)],
             is_closure: false,
@@ -174,15 +179,19 @@ impl CoverageSpan {
             .join("\n")
     }
 
-    /// If the span is part of a macro, and the macro is visible (expands directly to the given
-    /// body_span), returns the macro name symbol.
+    /// If the span is part of a macro, returns the macro name symbol.
     pub fn current_macro(&self) -> Option<Symbol> {
-        if let ExpnKind::Macro(MacroKind::Bang, current_macro) =
-            self.expn_span.ctxt().outer_expn_data().kind
-        {
-            return Some(current_macro);
-        }
-        None
+        self.current_macro_or_none
+            .borrow_mut()
+            .get_or_insert_with(|| {
+                if let ExpnKind::Macro(MacroKind::Bang, current_macro) =
+                    self.expn_span.ctxt().outer_expn_data().kind
+                {
+                    return Some(current_macro);
+                }
+                None
+            })
+            .map(|symbol| symbol)
     }
 
     /// If the span is part of a macro, and the macro is visible (expands directly to the given
@@ -474,8 +483,8 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
                 self.curr().expn_span.ctxt() != prev_expn_span.ctxt()
             }) {
                 let merged_prefix_len = self.curr_original_span.lo() - self.curr().span.lo();
-                let after_macro_bang = merged_prefix_len
-                    + BytePos(visible_macro.to_string().bytes().count() as u32 + 1);
+                let after_macro_bang =
+                    merged_prefix_len + BytePos(visible_macro.as_str().bytes().count() as u32 + 1);
                 let mut macro_name_cov = self.curr().clone();
                 self.curr_mut().span =
                     self.curr().span.with_lo(self.curr().span.lo() + after_macro_bang);
@@ -766,6 +775,9 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
     }
 }
 
+/// See `function_source_span()` for a description of the two returned spans.
+/// If the MIR `Statement` is not contributive to computing coverage spans,
+/// returns `None`.
 pub(super) fn filtered_statement_span(
     statement: &'a Statement<'tcx>,
     body_span: Span,
@@ -811,6 +823,9 @@ pub(super) fn filtered_statement_span(
     }
 }
 
+/// See `function_source_span()` for a description of the two returned spans.
+/// If the MIR `Terminator` is not contributive to computing coverage spans,
+/// returns `None`.
 pub(super) fn filtered_terminator_span(
     terminator: &'a Terminator<'tcx>,
     body_span: Span,
@@ -844,8 +859,21 @@ pub(super) fn filtered_terminator_span(
     }
 }
 
-/// Returns the span within the function source body, and the given span, which will be different
-/// if the given span is an expansion (macro, syntactic sugar, etc.).
+/// Returns two spans from the given span (the span associated with a
+/// `Statement` or `Terminator`):
+///
+///   1. An extrapolated span (pre-expansion[^1]) corresponding to a range within
+///      the function's body source. This span is guaranteed to be contained
+///      within, or equal to, the `body_span`. If the extrapolated span is not
+///      contained within the `body_span`, the `body_span` is returned.
+///   2. The actual `span` value from the `Statement`, before expansion.
+///
+/// Only the first span is used when computing coverage code regions. The second
+/// span is useful if additional expansion data is needed (such as to look up
+/// the macro name for a composed span within that macro).)
+///
+/// [^1]Expansions result from Rust syntax including macros, syntactic
+/// sugar, etc.).
 #[inline]
 fn function_source_span(span: Span, body_span: Span) -> (Span, Span) {
     let original_span = original_sp(span, body_span).with_ctxt(body_span.ctxt());
diff --git a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt
index 5d266b5db15f2..8256daa1419b3 100644
--- a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt
+++ b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-84561.txt
@@ -10,7 +10,7 @@
   | Unexecuted instantiation: <issue_84561::Foo as core::cmp::PartialEq>::ne
   ------------------
     5|       |struct Foo(u32);
-    6|      1|fn test2() {
+    6|      1|fn test3() {
     7|      1|    let is_true = std::env::args().len() == 1;
     8|      1|    let bar = Foo(1);
     9|      1|    assert_eq!(bar, Foo(1));
@@ -173,8 +173,24 @@
   160|      1|    debug!("debug is enabled");
   161|      1|}
   162|       |
-  163|      1|fn main() {
-  164|      1|    test1();
-  165|      1|    test2();
-  166|      1|}
+  163|       |macro_rules! call_debug {
+  164|       |    ($($arg:tt)+) => (
+  165|      1|        fn call_print(s: &str) {
+  166|      1|            print!("{}", s);
+  167|      1|        }
+  168|       |
+  169|       |        call_print("called from call_debug: ");
+  170|       |        debug!($($arg)+);
+  171|       |    );
+  172|       |}
+  173|       |
+  174|      1|fn test2() {
+  175|      1|    call_debug!("debug is enabled");
+  176|      1|}
+  177|       |
+  178|      1|fn main() {
+  179|      1|    test1();
+  180|      1|    test2();
+  181|      1|    test3();
+  182|      1|}
 
diff --git a/src/test/run-make-fulldeps/coverage/issue-84561.rs b/src/test/run-make-fulldeps/coverage/issue-84561.rs
index 5c8fd0b7caeaa..b39a289c45e20 100644
--- a/src/test/run-make-fulldeps/coverage/issue-84561.rs
+++ b/src/test/run-make-fulldeps/coverage/issue-84561.rs
@@ -3,7 +3,7 @@
 // expect-exit-status-101
 #[derive(PartialEq, Eq)]
 struct Foo(u32);
-fn test2() {
+fn test3() {
     let is_true = std::env::args().len() == 1;
     let bar = Foo(1);
     assert_eq!(bar, Foo(1));
@@ -160,7 +160,23 @@ fn test1() {
     debug!("debug is enabled");
 }
 
+macro_rules! call_debug {
+    ($($arg:tt)+) => (
+        fn call_print(s: &str) {
+            print!("{}", s);
+        }
+
+        call_print("called from call_debug: ");
+        debug!($($arg)+);
+    );
+}
+
+fn test2() {
+    call_debug!("debug is enabled");
+}
+
 fn main() {
     test1();
     test2();
+    test3();
 }

From 31ae3b2bdb9376b749fc1d64b531e86806e03c73 Mon Sep 17 00:00:00 2001
From: Jack Huey <jack.huey@umassmed.edu>
Date: Wed, 28 Apr 2021 10:18:52 -0400
Subject: [PATCH 06/12] Add HAS_RE_LATE_BOUND if there are bound vars

---
 compiler/rustc_middle/src/ty/flags.rs              |  4 ++++
 .../ui/lifetimes/issue-83737-erasing-bound-vars.rs | 14 ++++++++++++++
 src/test/ui/lifetimes/issue-84604.rs               |  9 +++++++++
 3 files changed, 27 insertions(+)
 create mode 100644 src/test/ui/lifetimes/issue-83737-erasing-bound-vars.rs
 create mode 100644 src/test/ui/lifetimes/issue-84604.rs

diff --git a/compiler/rustc_middle/src/ty/flags.rs b/compiler/rustc_middle/src/ty/flags.rs
index 01bc5cc761ca6..92288c8982744 100644
--- a/compiler/rustc_middle/src/ty/flags.rs
+++ b/compiler/rustc_middle/src/ty/flags.rs
@@ -59,6 +59,10 @@ impl FlagComputation {
     {
         let mut computation = FlagComputation::new();
 
+        if !value.bound_vars().is_empty() {
+            computation.flags = computation.flags | TypeFlags::HAS_RE_LATE_BOUND;
+        }
+
         f(&mut computation, value.skip_binder());
 
         self.add_flags(computation.flags);
diff --git a/src/test/ui/lifetimes/issue-83737-erasing-bound-vars.rs b/src/test/ui/lifetimes/issue-83737-erasing-bound-vars.rs
new file mode 100644
index 0000000000000..c496a3556c84e
--- /dev/null
+++ b/src/test/ui/lifetimes/issue-83737-erasing-bound-vars.rs
@@ -0,0 +1,14 @@
+// build-pass
+// compile-flags: --edition 2018
+// compile-flags: --crate-type rlib
+
+use std::future::Future;
+
+async fn handle<F>(slf: &F)
+where
+    F: Fn(&()) -> Box<dyn for<'a> Future<Output = ()> + Unpin>,
+{
+    (slf)(&()).await;
+}
+
+fn main() {}
diff --git a/src/test/ui/lifetimes/issue-84604.rs b/src/test/ui/lifetimes/issue-84604.rs
new file mode 100644
index 0000000000000..df8368da0a09a
--- /dev/null
+++ b/src/test/ui/lifetimes/issue-84604.rs
@@ -0,0 +1,9 @@
+// run-pass
+// compile-flags: -Zsymbol-mangling-version=v0
+
+pub fn f<T: ?Sized>() {}
+pub trait Frob<T: ?Sized> {}
+fn main() {
+    f::<dyn Frob<str>>();
+    f::<dyn for<'a> Frob<str>>();
+}

From 27fc7cbba9026add8a469587ea7aba9d9291941d Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Wed, 28 Apr 2021 07:19:49 -0700
Subject: [PATCH 07/12] Update LLVM for more wasm simd updates

This fixes the temporary regression introduced in #84339 where the wasm
target uses `fpto{s,u}i` intrinsics but the codegen for those intrinsics
with the `+nontrapping-fptoint` LLVM feature wasn't very good (aka it
didn't use the wasm instruction). The fixes brought in here fix that and
also implement the second-to-last simd instruction in LLVM.
---
 src/llvm-project | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/llvm-project b/src/llvm-project
index 0ed6038a318e3..06c2b9d1e23b7 160000
--- a/src/llvm-project
+++ b/src/llvm-project
@@ -1 +1 @@
-Subproject commit 0ed6038a318e34e3d76a9e55bdebc4cfd17f902a
+Subproject commit 06c2b9d1e23b73ffb5059769542097b86d5a4623

From e6a731eb90fe3d47d89416e199832af4248399f6 Mon Sep 17 00:00:00 2001
From: Amanieu d'Antras <amanieu@gmail.com>
Date: Wed, 28 Apr 2021 16:28:59 +0100
Subject: [PATCH 08/12] Be stricter about rejecting LLVM reserved registers in
 asm!

---
 compiler/rustc_target/src/asm/aarch64.rs      | 10 +++---
 compiler/rustc_target/src/asm/arm.rs          |  3 +-
 compiler/rustc_target/src/asm/hexagon.rs      |  3 +-
 compiler/rustc_target/src/asm/riscv.rs        |  3 +-
 compiler/rustc_target/src/asm/x86.rs          | 32 +++++++++++++++++--
 .../unstable-book/src/library-features/asm.md | 25 ++++++++-------
 src/test/codegen/asm-multiple-options.rs      |  2 +-
 src/test/codegen/asm-options.rs               |  2 +-
 src/test/pretty/asm.pp                        |  2 +-
 src/test/pretty/asm.rs                        |  2 +-
 10 files changed, 59 insertions(+), 25 deletions(-)

diff --git a/compiler/rustc_target/src/asm/aarch64.rs b/compiler/rustc_target/src/asm/aarch64.rs
index e7c9edea7653a..dd51574efca0a 100644
--- a/compiler/rustc_target/src/asm/aarch64.rs
+++ b/compiler/rustc_target/src/asm/aarch64.rs
@@ -83,10 +83,8 @@ def_regs! {
         x13: reg = ["x13", "w13"],
         x14: reg = ["x14", "w14"],
         x15: reg = ["x15", "w15"],
-        x16: reg = ["x16", "w16"],
         x17: reg = ["x17", "w17"],
         x18: reg = ["x18", "w18"],
-        x19: reg = ["x19", "w19"],
         x20: reg = ["x20", "w20"],
         x21: reg = ["x21", "w21"],
         x22: reg = ["x22", "w22"],
@@ -96,7 +94,7 @@ def_regs! {
         x26: reg = ["x26", "w26"],
         x27: reg = ["x27", "w27"],
         x28: reg = ["x28", "w28"],
-        x30: reg = ["x30", "w30", "lr"],
+        x30: reg = ["x30", "w30", "lr", "wlr"],
         v0: vreg, vreg_low16 = ["v0", "b0", "h0", "s0", "d0", "q0"],
         v1: vreg, vreg_low16 = ["v1", "b1", "h1", "s1", "d1", "q1"],
         v2: vreg, vreg_low16 = ["v2", "b2", "h2", "s2", "d2", "q2"],
@@ -129,7 +127,11 @@ def_regs! {
         v29: vreg = ["v29", "b29", "h29", "s29", "d29", "q29"],
         v30: vreg = ["v30", "b30", "h30", "s30", "d30", "q30"],
         v31: vreg = ["v31", "b31", "h31", "s31", "d31", "q31"],
-        #error = ["x29", "fp"] =>
+        #error = ["x16", "w16"] =>
+            "x16 is used internally by LLVM and cannot be used as an operand for inline asm",
+        #error = ["x19", "w19"] =>
+            "x19 is used internally by LLVM and cannot be used as an operand for inline asm",
+        #error = ["x29", "w29", "fp", "wfp"] =>
             "the frame pointer cannot be used as an operand for inline asm",
         #error = ["sp", "wsp"] =>
             "the stack pointer cannot be used as an operand for inline asm",
diff --git a/compiler/rustc_target/src/asm/arm.rs b/compiler/rustc_target/src/asm/arm.rs
index a7a708fe7dec3..4c323fc35d643 100644
--- a/compiler/rustc_target/src/asm/arm.rs
+++ b/compiler/rustc_target/src/asm/arm.rs
@@ -98,7 +98,6 @@ def_regs! {
         r5: reg, reg_thumb = ["r5", "v2"],
         r7: reg, reg_thumb = ["r7", "v4"] % frame_pointer_r7,
         r8: reg = ["r8", "v5"],
-        r9: reg = ["r9", "v6", "rfp"],
         r10: reg = ["r10", "sl"],
         r11: reg = ["r11", "fp"] % frame_pointer_r11,
         r12: reg = ["r12", "ip"],
@@ -185,6 +184,8 @@ def_regs! {
         q15: qreg = ["q15"],
         #error = ["r6", "v3"] =>
             "r6 is used internally by LLVM and cannot be used as an operand for inline asm",
+        #error = ["r9", "v6", "rfp"] =>
+            "r9 is used internally by LLVM and cannot be used as an operand for inline asm",
         #error = ["r13", "sp"] =>
             "the stack pointer cannot be used as an operand for inline asm",
         #error = ["r15", "pc"] =>
diff --git a/compiler/rustc_target/src/asm/hexagon.rs b/compiler/rustc_target/src/asm/hexagon.rs
index d41941d0b4cd7..74afddb69dc75 100644
--- a/compiler/rustc_target/src/asm/hexagon.rs
+++ b/compiler/rustc_target/src/asm/hexagon.rs
@@ -60,7 +60,6 @@ def_regs! {
         r16: reg = ["r16"],
         r17: reg = ["r17"],
         r18: reg = ["r18"],
-        r19: reg = ["r19"],
         r20: reg = ["r20"],
         r21: reg = ["r21"],
         r22: reg = ["r22"],
@@ -70,6 +69,8 @@ def_regs! {
         r26: reg = ["r26"],
         r27: reg = ["r27"],
         r28: reg = ["r28"],
+        #error = ["r19"] =>
+            "r19 is used internally by LLVM and cannot be used as an operand for inline asm",
         #error = ["r29", "sp"] =>
             "the stack pointer cannot be used as an operand for inline asm",
         #error = ["r30", "fr"] =>
diff --git a/compiler/rustc_target/src/asm/riscv.rs b/compiler/rustc_target/src/asm/riscv.rs
index 185d6ac8246c9..e276a9175f9ab 100644
--- a/compiler/rustc_target/src/asm/riscv.rs
+++ b/compiler/rustc_target/src/asm/riscv.rs
@@ -66,7 +66,6 @@ def_regs! {
         x5: reg = ["x5", "t0"],
         x6: reg = ["x6", "t1"],
         x7: reg = ["x7", "t2"],
-        x9: reg = ["x9", "s1"],
         x10: reg = ["x10", "a0"],
         x11: reg = ["x11", "a1"],
         x12: reg = ["x12", "a2"],
@@ -121,6 +120,8 @@ def_regs! {
         f29: freg = ["f29", "ft9"],
         f30: freg = ["f30", "ft10"],
         f31: freg = ["f31", "ft11"],
+        #error = ["x9", "s1"] =>
+            "s1 is used internally by LLVM and cannot be used as an operand for inline asm",
         #error = ["x8", "s0", "fp"] =>
             "the frame pointer cannot be used as an operand for inline asm",
         #error = ["x2", "sp"] =>
diff --git a/compiler/rustc_target/src/asm/x86.rs b/compiler/rustc_target/src/asm/x86.rs
index 90660dad4c2a1..48f83ca7cd49a 100644
--- a/compiler/rustc_target/src/asm/x86.rs
+++ b/compiler/rustc_target/src/asm/x86.rs
@@ -152,13 +152,41 @@ fn high_byte(
     }
 }
 
+fn rbx_reserved(
+    arch: InlineAsmArch,
+    _has_feature: impl FnMut(&str) -> bool,
+    _target: &Target,
+) -> Result<(), &'static str> {
+    match arch {
+        InlineAsmArch::X86 => Ok(()),
+        InlineAsmArch::X86_64 => {
+            Err("rbx is used internally by LLVM and cannot be used as an operand for inline asm")
+        }
+        _ => unreachable!(),
+    }
+}
+
+fn esi_reserved(
+    arch: InlineAsmArch,
+    _has_feature: impl FnMut(&str) -> bool,
+    _target: &Target,
+) -> Result<(), &'static str> {
+    match arch {
+        InlineAsmArch::X86 => {
+            Err("esi is used internally by LLVM and cannot be used as an operand for inline asm")
+        }
+        InlineAsmArch::X86_64 => Ok(()),
+        _ => unreachable!(),
+    }
+}
+
 def_regs! {
     X86 X86InlineAsmReg X86InlineAsmRegClass {
         ax: reg, reg_abcd = ["ax", "eax", "rax"],
-        bx: reg, reg_abcd = ["bx", "ebx", "rbx"],
+        bx: reg, reg_abcd = ["bx", "ebx", "rbx"] % rbx_reserved,
         cx: reg, reg_abcd = ["cx", "ecx", "rcx"],
         dx: reg, reg_abcd = ["dx", "edx", "rdx"],
-        si: reg = ["si", "esi", "rsi"],
+        si: reg = ["si", "esi", "rsi"] % esi_reserved,
         di: reg = ["di", "edi", "rdi"],
         r8: reg = ["r8", "r8w", "r8d"] % x86_64_only,
         r9: reg = ["r9", "r9w", "r9d"] % x86_64_only,
diff --git a/src/doc/unstable-book/src/library-features/asm.md b/src/doc/unstable-book/src/library-features/asm.md
index 4f9033cedc3ff..7c2bf62185530 100644
--- a/src/doc/unstable-book/src/library-features/asm.md
+++ b/src/doc/unstable-book/src/library-features/asm.md
@@ -535,20 +535,20 @@ Here is the list of currently supported register classes:
 
 | Architecture | Register class | Registers | LLVM constraint code |
 | ------------ | -------------- | --------- | -------------------- |
-| x86 | `reg` | `ax`, `bx`, `cx`, `dx`, `si`, `di`, `r[8-15]` (x86-64 only) | `r` |
+| x86 | `reg` | `ax`, `bx`, `cx`, `dx`, `si`, `di`, `bp`, `r[8-15]` (x86-64 only) | `r` |
 | x86 | `reg_abcd` | `ax`, `bx`, `cx`, `dx` | `Q` |
 | x86-32 | `reg_byte` | `al`, `bl`, `cl`, `dl`, `ah`, `bh`, `ch`, `dh` | `q` |
-| x86-64 | `reg_byte`\* | `al`, `bl`, `cl`, `dl`, `sil`, `dil`, `r[8-15]b` | `q` |
+| x86-64 | `reg_byte`\* | `al`, `bl`, `cl`, `dl`, `sil`, `dil`, `bpl`, `r[8-15]b` | `q` |
 | x86 | `xmm_reg` | `xmm[0-7]` (x86) `xmm[0-15]` (x86-64) | `x` |
 | x86 | `ymm_reg` | `ymm[0-7]` (x86) `ymm[0-15]` (x86-64) | `x` |
 | x86 | `zmm_reg` | `zmm[0-7]` (x86) `zmm[0-31]` (x86-64) | `v` |
 | x86 | `kreg` | `k[1-7]` | `Yk` |
-| AArch64 | `reg` | `x[0-28]`, `x30` | `r` |
+| AArch64 | `reg` | `x[0-30]` | `r` |
 | AArch64 | `vreg` | `v[0-31]` | `w` |
 | AArch64 | `vreg_low16` | `v[0-15]` | `x` |
-| ARM | `reg` | `r[0-5]` `r7`\*, `r[8-10]`, `r11`\*, `r12`, `r14` | `r` |
+| ARM | `reg` | `r[0-12]`, `r14` | `r` |
 | ARM (Thumb) | `reg_thumb` | `r[0-r7]` | `l` |
-| ARM (ARM) | `reg_thumb` | `r[0-r10]`, `r12`, `r14` | `l` |
+| ARM (ARM) | `reg_thumb` | `r[0-r12]`, `r14` | `l` |
 | ARM | `sreg` | `s[0-31]` | `t` |
 | ARM | `sreg_low16` | `s[0-15]` | `x` |
 | ARM | `dreg` | `d[0-31]` | `w` |
@@ -573,9 +573,7 @@ Here is the list of currently supported register classes:
 >
 > Note #3: NVPTX doesn't have a fixed register set, so named registers are not supported.
 >
-> Note #4: On ARM the frame pointer is either `r7` or `r11` depending on the platform.
->
-> Note #5: WebAssembly doesn't have registers, so named registers are not supported.
+> Note #4: WebAssembly doesn't have registers, so named registers are not supported.
 
 Additional register classes may be added in the future based on demand (e.g. MMX, x87, etc).
 
@@ -677,13 +675,15 @@ Some registers cannot be used for input or output operands:
 | All | `sp` | The stack pointer must be restored to its original value at the end of an asm code block. |
 | All | `bp` (x86), `x29` (AArch64), `x8` (RISC-V), `fr` (Hexagon), `$fp` (MIPS) | The frame pointer cannot be used as an input or output. |
 | ARM | `r7` or `r11` | On ARM the frame pointer can be either `r7` or `r11` depending on the target. The frame pointer cannot be used as an input or output. |
-| ARM | `r6` | `r6` is used internally by LLVM as a base pointer and therefore cannot be used as an input or output. |
+| All | `si` (x86-32), `bx` (x86-64), `r6` (ARM), `x19` (AArch64), `r19` (Hexagon), `x9` (RISC-V) | This is used internally by LLVM as a "base pointer" for functions with complex stack frames. |
 | x86 | `k0` | This is a constant zero register which can't be modified. |
 | x86 | `ip` | This is the program counter, not a real register. |
 | x86 | `mm[0-7]` | MMX registers are not currently supported (but may be in the future). |
 | x86 | `st([0-7])` | x87 registers are not currently supported (but may be in the future). |
 | AArch64 | `xzr` | This is a constant zero register which can't be modified. |
+| AArch64 | `x16` | This is used internally by LLVM for speculative load hardening. |
 | ARM | `pc` | This is the program counter, not a real register. |
+| ARM | `r9` | This is a reserved register on some ARM targets. |
 | MIPS | `$0` or `$zero` | This is a constant zero register which can't be modified. |
 | MIPS | `$1` or `$at` | Reserved for assembler. |
 | MIPS | `$26`/`$k0`, `$27`/`$k1` | OS-reserved registers. |
@@ -693,9 +693,10 @@ Some registers cannot be used for input or output operands:
 | RISC-V | `gp`, `tp` | These registers are reserved and cannot be used as inputs or outputs. |
 | Hexagon | `lr` | This is the link register which cannot be used as an input or output. |
 
-In some cases LLVM will allocate a "reserved register" for `reg` operands even though this register cannot be explicitly specified. Assembly code making use of reserved registers should be careful since `reg` operands may alias with those registers. Reserved registers are:
-- The frame pointer on all architectures.
-- `r6` on ARM.
+In some cases LLVM will allocate a "reserved register" for `reg` operands even though this register cannot be explicitly specified. Assembly code making use of reserved registers should be careful since `reg` operands may alias with those registers. Reserved registers are the frame pointer and base pointer
+- The frame pointer and LLVM base pointer on all architectures.
+- `x16` on AArch64.
+- `r6` and `r9` on ARM.
 
 ## Template modifiers
 
diff --git a/src/test/codegen/asm-multiple-options.rs b/src/test/codegen/asm-multiple-options.rs
index c702742bf1a63..baf9f3e9bd14d 100644
--- a/src/test/codegen/asm-multiple-options.rs
+++ b/src/test/codegen/asm-multiple-options.rs
@@ -10,7 +10,7 @@
 #[no_mangle]
 pub unsafe fn pure(x: i32) {
     let y: i32;
-    asm!("", out("ax") y, in("bx") x, options(pure), options(nomem));
+    asm!("", out("ax") y, in("cx") x, options(pure), options(nomem));
 }
 
 pub static mut VAR: i32 = 0;
diff --git a/src/test/codegen/asm-options.rs b/src/test/codegen/asm-options.rs
index 21e7eb4379634..70391661b0cfb 100644
--- a/src/test/codegen/asm-options.rs
+++ b/src/test/codegen/asm-options.rs
@@ -10,7 +10,7 @@
 #[no_mangle]
 pub unsafe fn pure(x: i32) {
     let y: i32;
-    asm!("", out("ax") y, in("bx") x, options(pure, nomem));
+    asm!("", out("ax") y, in("cx") x, options(pure, nomem));
 }
 
 // CHECK-LABEL: @noreturn
diff --git a/src/test/pretty/asm.pp b/src/test/pretty/asm.pp
index c86d8a1197188..a2065039692b7 100644
--- a/src/test/pretty/asm.pp
+++ b/src/test/pretty/asm.pp
@@ -21,7 +21,7 @@
         asm!("{0}", out(reg) a);
         asm!("{0}", inout(reg) b);
         asm!("{0} {1}", out(reg) _, inlateout(reg) b => _);
-        asm!("", out("al") _, lateout("rbx") _);
+        asm!("", out("al") _, lateout("rcx") _);
         asm!("inst1\ninst2");
         asm!("inst1 {0}, 42\ninst2 {1}, 24", in(reg) a, out(reg) b);
         asm!("inst2 {1}, 24\ninst1 {0}, 42", in(reg) a, out(reg) b);
diff --git a/src/test/pretty/asm.rs b/src/test/pretty/asm.rs
index 33f25e5216b4e..1156ab769a043 100644
--- a/src/test/pretty/asm.rs
+++ b/src/test/pretty/asm.rs
@@ -15,7 +15,7 @@ pub fn main() {
         asm!("{0}", out(reg) a);
         asm!("{name}", name = inout(reg) b);
         asm!("{} {}", out(reg) _, inlateout(reg) b => _);
-        asm!("", out("al") _, lateout("rbx") _);
+        asm!("", out("al") _, lateout("rcx") _);
         asm!("inst1", "inst2");
         asm!("inst1 {}, 42", "inst2 {}, 24", in(reg) a, out(reg) b);
         asm!("inst2 {1}, 24", "inst1 {0}, 42", in(reg) a, out(reg) b);

From c9fbaa6a9f68c74608324cc01e5985d9635cb021 Mon Sep 17 00:00:00 2001
From: Jack Huey <31162821+jackh726@users.noreply.github.com>
Date: Wed, 28 Apr 2021 15:51:54 -0400
Subject: [PATCH 09/12] Add a comment

---
 compiler/rustc_middle/src/ty/flags.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/compiler/rustc_middle/src/ty/flags.rs b/compiler/rustc_middle/src/ty/flags.rs
index 92288c8982744..d2e233f67d7bf 100644
--- a/compiler/rustc_middle/src/ty/flags.rs
+++ b/compiler/rustc_middle/src/ty/flags.rs
@@ -59,6 +59,9 @@ impl FlagComputation {
     {
         let mut computation = FlagComputation::new();
 
+        // In some cases, there are binders with variables that are unused (e.g., `for<'a> fn(u32)`).
+        // Set the flag to represent the `'a` in this example. Note that if there are late bound types
+        // or consts, this flag will also get set.
         if !value.bound_vars().is_empty() {
             computation.flags = computation.flags | TypeFlags::HAS_RE_LATE_BOUND;
         }

From 3e016a7682699ac23e48b4c6571c3d78503abf4d Mon Sep 17 00:00:00 2001
From: Ben-Lichtman <Ben_Lichtman@icloud.com>
Date: Wed, 28 Apr 2021 19:43:33 -0700
Subject: [PATCH 10/12] Minor grammar tweaks for readability

---
 library/alloc/src/collections/btree/node.rs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/library/alloc/src/collections/btree/node.rs b/library/alloc/src/collections/btree/node.rs
index f330a1bb3dcfe..af403496e38e9 100644
--- a/library/alloc/src/collections/btree/node.rs
+++ b/library/alloc/src/collections/btree/node.rs
@@ -89,7 +89,7 @@ impl<K, V> LeafNode<K, V> {
 
 /// The underlying representation of internal nodes. As with `LeafNode`s, these should be hidden
 /// behind `BoxedNode`s to prevent dropping uninitialized keys and values. Any pointer to an
-/// `InternalNode` can be directly casted to a pointer to the underlying `LeafNode` portion of the
+/// `InternalNode` can be directly cast to a pointer to the underlying `LeafNode` portion of the
 /// node, allowing code to act on leaf and internal nodes generically without having to even check
 /// which of the two a pointer is pointing at. This property is enabled by the use of `repr(C)`.
 #[repr(C)]
@@ -408,7 +408,7 @@ impl<K, V> NodeRef<marker::Dying, K, V, marker::LeafOrInternal> {
 }
 
 impl<'a, K, V, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
-    /// Temporarily takes out another, mutable reference to the same node. Beware, as
+    /// Temporarily takes out another mutable reference to the same node. Beware, as
     /// this method is very dangerous, doubly so since it may not immediately appear
     /// dangerous.
     ///
@@ -759,7 +759,7 @@ impl<BorrowType, K, V, NodeType, HandleType> PartialEq
 impl<BorrowType, K, V, NodeType, HandleType>
     Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType>
 {
-    /// Temporarily takes out another, immutable handle on the same location.
+    /// Temporarily takes out another immutable handle on the same location.
     pub fn reborrow(&self) -> Handle<NodeRef<marker::Immut<'_>, K, V, NodeType>, HandleType> {
         // We can't use Handle::new_kv or Handle::new_edge because we don't know our type
         Handle { node: self.node.reborrow(), idx: self.idx, _marker: PhantomData }
@@ -767,7 +767,7 @@ impl<BorrowType, K, V, NodeType, HandleType>
 }
 
 impl<'a, K, V, NodeType, HandleType> Handle<NodeRef<marker::Mut<'a>, K, V, NodeType>, HandleType> {
-    /// Temporarily takes out another, mutable handle on the same location. Beware, as
+    /// Temporarily takes out another mutable handle on the same location. Beware, as
     /// this method is very dangerous, doubly so since it may not immediately appear
     /// dangerous.
     ///

From 8c0469552e879f6319f8f96db660bab9eae1de5c Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Thu, 29 Apr 2021 10:40:10 +0200
Subject: [PATCH 11/12] Remove unnecessary CSS rules for search results

---
 src/librustdoc/html/static/rustdoc.css | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index a024fa49b0e8b..3eda2bea7fe6a 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -385,13 +385,6 @@ nav.sub {
 	position: relative;
 }
 
-#results {
-	position: absolute;
-	right: 0;
-	left: 0;
-	overflow: auto;
-}
-
 #results > table {
 	width: 100%;
 	table-layout: fixed;

From a20831e7a6617953e8e9d3f94140a558feb1e8ce Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Thu, 29 Apr 2021 11:26:35 +0200
Subject: [PATCH 12/12] Remove unneeded bottom margin on search results

---
 src/librustdoc/html/static/rustdoc.css | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index a024fa49b0e8b..62ea0935360f1 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -395,7 +395,6 @@ nav.sub {
 #results > table {
 	width: 100%;
 	table-layout: fixed;
-	margin-bottom: 40px;
 }
 
 .content pre.line-numbers {