coverage: Remove `-Zcoverage-options=no-mir-spans`

This flag turned out to be less useful than anticipated, and interferes with
work towards expansion support.

9 files changed, 5 insertions, 226 deletions

diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 8771bb44050..86faab62d03 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -778,8 +778,8 @@ fn test_unstable_options_tracking_hash() {
         coverage_options,
         CoverageOptions {
             level: CoverageLevel::Mcdc,
-            no_mir_spans: true,
-            discard_all_spans_in_codegen: true
+            // (don't collapse test-only options onto the same line)
+            discard_all_spans_in_codegen: true,
         }
     );
     tracked!(crate_attr, vec!["abc".to_string()]);
diff --git a/compiler/rustc_mir_transform/src/coverage/mappings.rs b/compiler/rustc_mir_transform/src/coverage/mappings.rs
index b4b4d0416fb..c79b76d90f2 100644
--- a/compiler/rustc_mir_transform/src/coverage/mappings.rs
+++ b/compiler/rustc_mir_transform/src/coverage/mappings.rs
@@ -82,15 +82,11 @@ pub(super) fn extract_all_mapping_info_from_mir<'tcx>(
     let mut mcdc_degraded_branches = vec![];
     let mut mcdc_mappings = vec![];
 
-    if hir_info.is_async_fn || tcx.sess.coverage_no_mir_spans() {
+    if hir_info.is_async_fn {
         // An async function desugars into a function that returns a future,
         // with the user code wrapped in a closure. Any spans in the desugared
         // outer function will be unhelpful, so just keep the signature span
         // and ignore all of the spans in the MIR body.
-        //
-        // When debugging flag `-Zcoverage-options=no-mir-spans` is set, we need
-        // to give the same treatment to _all_ functions, because `llvm-cov`
-        // seems to ignore functions that don't have any ordinary code spans.
         if let Some(span) = hir_info.fn_sig_span {
             code_mappings.push(CodeMapping { span, bcb: START_BCB });
         }
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 8f624e0fb2f..e82f4527c6c 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -182,14 +182,6 @@ pub enum InstrumentCoverage {
 pub struct CoverageOptions {
     pub level: CoverageLevel,
 
-    /// `-Zcoverage-options=no-mir-spans`: Don't extract block coverage spans
-    /// from MIR statements/terminators, making it easier to inspect/debug
-    /// branch and MC/DC coverage mappings.
-    ///
-    /// For internal debugging only. If other code changes would make it hard
-    /// to keep supporting this flag, remove it.
-    pub no_mir_spans: bool,
-
     /// `-Zcoverage-options=discard-all-spans-in-codegen`: During codegen,
     /// discard all coverage spans as though they were invalid. Needed by
     /// regression tests for #133606, because we don't have an easy way to
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 44b35e8921e..880b08d4444 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -755,8 +755,7 @@ mod desc {
     pub(crate) const parse_linker_flavor: &str = ::rustc_target::spec::LinkerFlavorCli::one_of();
     pub(crate) const parse_dump_mono_stats: &str = "`markdown` (default) or `json`";
     pub(crate) const parse_instrument_coverage: &str = parse_bool;
-    pub(crate) const parse_coverage_options: &str =
-        "`block` | `branch` | `condition` | `mcdc` | `no-mir-spans`";
+    pub(crate) const parse_coverage_options: &str = "`block` | `branch` | `condition` | `mcdc`";
     pub(crate) const parse_instrument_xray: &str = "either a boolean (`yes`, `no`, `on`, `off`, etc), or a comma separated list of settings: `always` or `never` (mutually exclusive), `ignore-loops`, `instruction-threshold=N`, `skip-entry`, `skip-exit`";
     pub(crate) const parse_unpretty: &str = "`string` or `string=string`";
     pub(crate) const parse_treat_err_as_bug: &str = "either no value or a non-negative number";
@@ -1460,7 +1459,6 @@ pub mod parse {
                 "branch" => slot.level = CoverageLevel::Branch,
                 "condition" => slot.level = CoverageLevel::Condition,
                 "mcdc" => slot.level = CoverageLevel::Mcdc,
-                "no-mir-spans" => slot.no_mir_spans = true,
                 "discard-all-spans-in-codegen" => slot.discard_all_spans_in_codegen = true,
                 _ => return false,
             }
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index e7097ec8327..c311a726aa7 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -359,11 +359,6 @@ impl Session {
             && self.opts.unstable_opts.coverage_options.level >= CoverageLevel::Mcdc
     }
 
-    /// True if `-Zcoverage-options=no-mir-spans` was passed.
-    pub fn coverage_no_mir_spans(&self) -> bool {
-        self.opts.unstable_opts.coverage_options.no_mir_spans
-    }
-
     /// True if `-Zcoverage-options=discard-all-spans-in-codegen` was passed.
     pub fn coverage_discard_all_spans_in_codegen(&self) -> bool {
         self.opts.unstable_opts.coverage_options.discard_all_spans_in_codegen
diff --git a/tests/coverage/branch/no-mir-spans.cov-map b/tests/coverage/branch/no-mir-spans.cov-map
deleted file mode 100644
index 4f893cba1f8..00000000000
--- a/tests/coverage/branch/no-mir-spans.cov-map
+++ /dev/null
@@ -1,63 +0,0 @@
-Function name: no_mir_spans::while_cond
-Raw bytes (18): 0x[01, 01, 01, 05, 01, 02, 01, 10, 01, 00, 10, 20, 02, 01, 04, 0b, 00, 10]
-Number of files: 1
-- file 0 => $DIR/no-mir-spans.rs
-Number of expressions: 1
-- expression 0 operands: lhs = Counter(1), rhs = Counter(0)
-Number of file 0 mappings: 2
-- Code(Counter(0)) at (prev + 16, 1) to (start + 0, 16)
-- Branch { true: Expression(0, Sub), false: Counter(0) } at (prev + 4, 11) to (start + 0, 16)
-    true  = (c1 - c0)
-    false = c0
-Highest counter ID seen: c0
-
-Function name: no_mir_spans::while_cond_not
-Raw bytes (18): 0x[01, 01, 01, 05, 01, 02, 01, 19, 01, 00, 14, 20, 02, 01, 04, 0b, 00, 14]
-Number of files: 1
-- file 0 => $DIR/no-mir-spans.rs
-Number of expressions: 1
-- expression 0 operands: lhs = Counter(1), rhs = Counter(0)
-Number of file 0 mappings: 2
-- Code(Counter(0)) at (prev + 25, 1) to (start + 0, 20)
-- Branch { true: Expression(0, Sub), false: Counter(0) } at (prev + 4, 11) to (start + 0, 20)
-    true  = (c1 - c0)
-    false = c0
-Highest counter ID seen: c0
-
-Function name: no_mir_spans::while_op_and
-Raw bytes (31): 0x[01, 01, 04, 09, 05, 09, 01, 0f, 09, 01, 05, 03, 01, 22, 01, 00, 12, 20, 05, 02, 05, 0b, 00, 10, 20, 06, 0a, 00, 14, 00, 19]
-Number of files: 1
-- file 0 => $DIR/no-mir-spans.rs
-Number of expressions: 4
-- expression 0 operands: lhs = Counter(2), rhs = Counter(1)
-- expression 1 operands: lhs = Counter(2), rhs = Counter(0)
-- expression 2 operands: lhs = Expression(3, Add), rhs = Counter(2)
-- expression 3 operands: lhs = Counter(0), rhs = Counter(1)
-Number of file 0 mappings: 3
-- Code(Counter(0)) at (prev + 34, 1) to (start + 0, 18)
-- Branch { true: Counter(1), false: Expression(0, Sub) } at (prev + 5, 11) to (start + 0, 16)
-    true  = c1
-    false = (c2 - c1)
-- Branch { true: Expression(1, Sub), false: Expression(2, Sub) } at (prev + 0, 20) to (start + 0, 25)
-    true  = (c2 - c0)
-    false = ((c0 + c1) - c2)
-Highest counter ID seen: c1
-
-Function name: no_mir_spans::while_op_or
-Raw bytes (29): 0x[01, 01, 03, 09, 05, 09, 0b, 01, 05, 03, 01, 2d, 01, 00, 11, 20, 05, 02, 05, 0b, 00, 10, 20, 06, 01, 00, 14, 00, 19]
-Number of files: 1
-- file 0 => $DIR/no-mir-spans.rs
-Number of expressions: 3
-- expression 0 operands: lhs = Counter(2), rhs = Counter(1)
-- expression 1 operands: lhs = Counter(2), rhs = Expression(2, Add)
-- expression 2 operands: lhs = Counter(0), rhs = Counter(1)
-Number of file 0 mappings: 3
-- Code(Counter(0)) at (prev + 45, 1) to (start + 0, 17)
-- Branch { true: Counter(1), false: Expression(0, Sub) } at (prev + 5, 11) to (start + 0, 16)
-    true  = c1
-    false = (c2 - c1)
-- Branch { true: Expression(1, Sub), false: Counter(0) } at (prev + 0, 20) to (start + 0, 25)
-    true  = (c2 - (c0 + c1))
-    false = c0
-Highest counter ID seen: c1
-
diff --git a/tests/coverage/branch/no-mir-spans.coverage b/tests/coverage/branch/no-mir-spans.coverage
deleted file mode 100644
index 2cae98ed3ff..00000000000
--- a/tests/coverage/branch/no-mir-spans.coverage
+++ /dev/null
@@ -1,77 +0,0 @@
-   LL|       |#![feature(coverage_attribute)]
-   LL|       |//@ edition: 2021
-   LL|       |//@ compile-flags: -Zcoverage-options=branch,no-mir-spans
-   LL|       |//@ llvm-cov-flags: --show-branches=count
-   LL|       |
-   LL|       |// Tests the behaviour of the `-Zcoverage-options=no-mir-spans` debugging flag.
-   LL|       |// The actual code below is just some non-trivial code copied from another test
-   LL|       |// (`while.rs`), and has no particular significance.
-   LL|       |
-   LL|       |macro_rules! no_merge {
-   LL|       |    () => {
-   LL|       |        for _ in 0..1 {}
-   LL|       |    };
-   LL|       |}
-   LL|       |
-   LL|      1|fn while_cond() {
-   LL|       |    no_merge!();
-   LL|       |
-   LL|       |    let mut a = 8;
-   LL|       |    while a > 0 {
-  ------------------
-  |  Branch (LL:11): [True: 8, False: 1]
-  ------------------
-   LL|       |        a -= 1;
-   LL|       |    }
-   LL|       |}
-   LL|       |
-   LL|      1|fn while_cond_not() {
-   LL|       |    no_merge!();
-   LL|       |
-   LL|       |    let mut a = 8;
-   LL|       |    while !(a == 0) {
-  ------------------
-  |  Branch (LL:11): [True: 8, False: 1]
-  ------------------
-   LL|       |        a -= 1;
-   LL|       |    }
-   LL|       |}
-   LL|       |
-   LL|      1|fn while_op_and() {
-   LL|       |    no_merge!();
-   LL|       |
-   LL|       |    let mut a = 8;
-   LL|       |    let mut b = 4;
-   LL|       |    while a > 0 && b > 0 {
-  ------------------
-  |  Branch (LL:11): [True: 5, False: 0]
-  |  Branch (LL:20): [True: 4, False: 1]
-  ------------------
-   LL|       |        a -= 1;
-   LL|       |        b -= 1;
-   LL|       |    }
-   LL|       |}
-   LL|       |
-   LL|      1|fn while_op_or() {
-   LL|       |    no_merge!();
-   LL|       |
-   LL|       |    let mut a = 4;
-   LL|       |    let mut b = 8;
-   LL|       |    while a > 0 || b > 0 {
-  ------------------
-  |  Branch (LL:11): [True: 4, False: 5]
-  |  Branch (LL:20): [True: 4, False: 1]
-  ------------------
-   LL|       |        a -= 1;
-   LL|       |        b -= 1;
-   LL|       |    }
-   LL|       |}
-   LL|       |
-   LL|       |#[coverage(off)]
-   LL|       |fn main() {
-   LL|       |    while_cond();
-   LL|       |    while_cond_not();
-   LL|       |    while_op_and();
-   LL|       |    while_op_or();
-   LL|       |}
-
diff --git a/tests/coverage/branch/no-mir-spans.rs b/tests/coverage/branch/no-mir-spans.rs
deleted file mode 100644
index acb268f2d45..00000000000
--- a/tests/coverage/branch/no-mir-spans.rs
+++ /dev/null
@@ -1,62 +0,0 @@
-#![feature(coverage_attribute)]
-//@ edition: 2021
-//@ compile-flags: -Zcoverage-options=branch,no-mir-spans
-//@ llvm-cov-flags: --show-branches=count
-
-// Tests the behaviour of the `-Zcoverage-options=no-mir-spans` debugging flag.
-// The actual code below is just some non-trivial code copied from another test
-// (`while.rs`), and has no particular significance.
-
-macro_rules! no_merge {
-    () => {
-        for _ in 0..1 {}
-    };
-}
-
-fn while_cond() {
-    no_merge!();
-
-    let mut a = 8;
-    while a > 0 {
-        a -= 1;
-    }
-}
-
-fn while_cond_not() {
-    no_merge!();
-
-    let mut a = 8;
-    while !(a == 0) {
-        a -= 1;
-    }
-}
-
-fn while_op_and() {
-    no_merge!();
-
-    let mut a = 8;
-    let mut b = 4;
-    while a > 0 && b > 0 {
-        a -= 1;
-        b -= 1;
-    }
-}
-
-fn while_op_or() {
-    no_merge!();
-
-    let mut a = 4;
-    let mut b = 8;
-    while a > 0 || b > 0 {
-        a -= 1;
-        b -= 1;
-    }
-}
-
-#[coverage(off)]
-fn main() {
-    while_cond();
-    while_cond_not();
-    while_op_and();
-    while_op_or();
-}
diff --git a/tests/ui/instrument-coverage/coverage-options.bad.stderr b/tests/ui/instrument-coverage/coverage-options.bad.stderr
index 1a6b30dc832..4a272cf97fb 100644
--- a/tests/ui/instrument-coverage/coverage-options.bad.stderr
+++ b/tests/ui/instrument-coverage/coverage-options.bad.stderr
@@ -1,2 +1,2 @@
-error: incorrect value `bad` for unstable option `coverage-options` - `block` | `branch` | `condition` | `mcdc` | `no-mir-spans` was expected
+error: incorrect value `bad` for unstable option `coverage-options` - `block` | `branch` | `condition` | `mcdc` was expected