diff --git a/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs b/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs
index 79f35ad5819f1..5a4e7fd9d07b4 100644
--- a/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs
@@ -16,9 +16,19 @@ pub fn expand_deriving_eq(
push: &mut dyn FnMut(Annotatable),
) {
let inline = cx.meta_word(span, sym::inline);
+ let no_coverage_ident =
+ rustc_ast::attr::mk_nested_word_item(Ident::new(sym::no_coverage, span));
+ let no_coverage_feature =
+ rustc_ast::attr::mk_list_item(Ident::new(sym::feature, span), vec![no_coverage_ident]);
+ let no_coverage = cx.meta_word(span, sym::no_coverage);
let hidden = rustc_ast::attr::mk_nested_word_item(Ident::new(sym::hidden, span));
let doc = rustc_ast::attr::mk_list_item(Ident::new(sym::doc, span), vec![hidden]);
- let attrs = vec![cx.attribute(inline), cx.attribute(doc)];
+ let attrs = vec![
+ cx.attribute(inline),
+ cx.attribute(no_coverage_feature),
+ cx.attribute(no_coverage),
+ cx.attribute(doc),
+ ];
let trait_def = TraitDef {
span,
attributes: Vec::new(),
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
index 2ac814bf22838..1faaa7e86f619 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
@@ -8,6 +8,7 @@ use rustc_codegen_ssa::traits::{ConstMethods, CoverageInfoMethods};
use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
use rustc_hir::def_id::{DefId, DefIdSet, LOCAL_CRATE};
use rustc_llvm::RustString;
+use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use rustc_middle::mir::coverage::CodeRegion;
use rustc_span::Symbol;
@@ -280,6 +281,10 @@ fn add_unused_functions<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) {
let mut unused_def_ids_by_file: FxHashMap<Symbol, Vec<DefId>> = FxHashMap::default();
for &non_codegenned_def_id in all_def_ids.difference(codegenned_def_ids) {
+ let codegen_fn_attrs = tcx.codegen_fn_attrs(non_codegenned_def_id);
+ if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NO_COVERAGE) {
+ continue;
+ }
// Make sure the non-codegenned (unused) function has a file_name
if let Some(non_codegenned_file_name) = tcx.covered_file_name(non_codegenned_def_id) {
let def_ids =
diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index 7ae7e0094c6d1..d5963d34dfaa5 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/compiler/rustc_feature/src/active.rs
@@ -649,6 +649,10 @@ declare_features! (
/// Allows `extern "wasm" fn`
(active, wasm_abi, "1.53.0", Some(83788), None),
+ /// Allows function attribute `#[no_coverage]`, to bypass coverage
+ /// instrumentation of that function.
+ (active, no_coverage, "1.53.0", Some(84605), None),
+
/// Allows trait bounds in `const fn`.
(active, const_fn_trait_bound, "1.53.0", Some(57563), None),
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index b8a0b8debcd31..5474fea9c7857 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -273,6 +273,13 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
template!(List: "address, memory, thread"),
experimental!(no_sanitize)
),
+ ungated!(
+ // Not exclusively gated at the crate level (though crate-level is
+ // supported). The feature can alternatively be enabled on individual
+ // functions.
+ no_coverage, AssumedUsed,
+ template!(Word),
+ ),
// FIXME: #14408 assume docs are used since rustdoc looks at them.
ungated!(doc, AssumedUsed, template!(List: "hidden|inline|...", NameValueStr: "string")),
diff --git a/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs b/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
index 7024d9a3d21db..93e7aeaffce37 100644
--- a/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
+++ b/compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
@@ -89,6 +89,10 @@ bitflags! {
/// #[cmse_nonsecure_entry]: with a TrustZone-M extension, declare a
/// function as an entry function from Non-Secure code.
const CMSE_NONSECURE_ENTRY = 1 << 14;
+ /// `#[no_coverage]`: indicates that the function should be ignored by
+ /// the MIR `InstrumentCoverage` pass and not added to the coverage map
+ /// during codegen.
+ const NO_COVERAGE = 1 << 15;
}
}
diff --git a/compiler/rustc_mir/src/transform/coverage/mod.rs b/compiler/rustc_mir/src/transform/coverage/mod.rs
index 3ef03ec21addd..eaeb44289cfb2 100644
--- a/compiler/rustc_mir/src/transform/coverage/mod.rs
+++ b/compiler/rustc_mir/src/transform/coverage/mod.rs
@@ -23,6 +23,7 @@ use rustc_index::vec::IndexVec;
use rustc_middle::hir;
use rustc_middle::hir::map::blocks::FnLikeNode;
use rustc_middle::ich::StableHashingContext;
+use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use rustc_middle::mir::coverage::*;
use rustc_middle::mir::{
self, BasicBlock, BasicBlockData, Coverage, SourceInfo, Statement, StatementKind, Terminator,
@@ -87,6 +88,11 @@ impl<'tcx> MirPass<'tcx> for InstrumentCoverage {
_ => {}
}
+ let codegen_fn_attrs = tcx.codegen_fn_attrs(mir_source.def_id());
+ if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NO_COVERAGE) {
+ return;
+ }
+
trace!("InstrumentCoverage starting for {:?}", mir_source.def_id());
Instrumentor::new(&self.name(), tcx, mir_body).inject_counters();
trace!("InstrumentCoverage starting for {:?}", mir_source.def_id());
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 4be187c5208cd..cb6c72b1317b2 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -781,6 +781,7 @@ symbols! {
no,
no_builtins,
no_core,
+ no_coverage,
no_crate_inject,
no_debug,
no_default_passes,
diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs
index 46ee82454326a..190c9d35934f9 100644
--- a/compiler/rustc_typeck/src/collect.rs
+++ b/compiler/rustc_typeck/src/collect.rs
@@ -2661,6 +2661,8 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
let mut inline_span = None;
let mut link_ordinal_span = None;
let mut no_sanitize_span = None;
+ let mut no_coverage_feature_enabled = false;
+ let mut no_coverage_attr = None;
for attr in attrs.iter() {
if tcx.sess.check_name(attr, sym::cold) {
codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD;
@@ -2724,6 +2726,15 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED;
} else if tcx.sess.check_name(attr, sym::no_mangle) {
codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE;
+ } else if attr.has_name(sym::feature) {
+ if let Some(list) = attr.meta_item_list() {
+ if list.iter().any(|nested_meta_item| nested_meta_item.has_name(sym::no_coverage)) {
+ tcx.sess.mark_attr_used(attr);
+ no_coverage_feature_enabled = true;
+ }
+ }
+ } else if tcx.sess.check_name(attr, sym::no_coverage) {
+ no_coverage_attr = Some(attr);
} else if tcx.sess.check_name(attr, sym::rustc_std_internal_symbol) {
codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL;
} else if tcx.sess.check_name(attr, sym::used) {
@@ -2934,6 +2945,23 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
}
}
+ if let Some(no_coverage_attr) = no_coverage_attr {
+ if tcx.sess.features_untracked().no_coverage || no_coverage_feature_enabled {
+ codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_COVERAGE
+ } else {
+ let mut err = feature_err(
+ &tcx.sess.parse_sess,
+ sym::no_coverage,
+ no_coverage_attr.span,
+ "the `#[no_coverage]` attribute is an experimental feature",
+ );
+ if tcx.sess.parse_sess.unstable_features.is_nightly_build() {
+ err.help("or, alternatively, add `#[feature(no_coverage)]` to the function");
+ }
+ err.emit();
+ }
+ }
+
codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
if !attr.has_name(sym::inline) {
return ia;
diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs
index cdb6006b1b354..0a3e5789e8bed 100644
--- a/library/core/src/cmp.rs
+++ b/library/core/src/cmp.rs
@@ -274,6 +274,8 @@ pub trait Eq: PartialEq<Self> {
//
// This should never be implemented by hand.
#[doc(hidden)]
+ #[cfg_attr(not(bootstrap), feature(no_coverage))]
+ #[cfg_attr(not(bootstrap), no_coverage)]
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
fn assert_receiver_is_total_eq(&self) {}
diff --git a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-83601.txt b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-83601.txt
new file mode 100644
index 0000000000000..46f3add9427b6
--- /dev/null
+++ b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-83601.txt
@@ -0,0 +1,22 @@
+ 1| |// Shows that rust-lang/rust/83601 is resolved
+ 2| |
+ 3| 3|#[derive(Debug, PartialEq, Eq)]
+ ^2
+ ------------------
+ | <issue_83601::Foo as core::cmp::PartialEq>::eq:
+ | 3| 2|#[derive(Debug, PartialEq, Eq)]
+ ------------------
+ | Unexecuted instantiation: <issue_83601::Foo as core::cmp::PartialEq>::ne
+ ------------------
+ 4| |struct Foo(u32);
+ 5| |
+ 6| 1|fn main() {
+ 7| 1| let bar = Foo(1);
+ 8| 0| assert_eq!(bar, Foo(1));
+ 9| 1| let baz = Foo(0);
+ 10| 0| assert_ne!(baz, Foo(1));
+ 11| 1| println!("{:?}", Foo(1));
+ 12| 1| println!("{:?}", bar);
+ 13| 1| println!("{:?}", baz);
+ 14| 1|}
+
diff --git a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.no_cov_crate.txt b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.no_cov_crate.txt
new file mode 100644
index 0000000000000..c4a7b0cc7e9f3
--- /dev/null
+++ b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.no_cov_crate.txt
@@ -0,0 +1,18 @@
+ 1| |// Enables `no_coverage` on the entire crate
+ 2| |#![feature(no_coverage)]
+ 3| |
+ 4| |#[no_coverage]
+ 5| |fn do_not_add_coverage_1() {
+ 6| | println!("called but not covered");
+ 7| |}
+ 8| |
+ 9| |#[no_coverage]
+ 10| |fn do_not_add_coverage_2() {
+ 11| | println!("called but not covered");
+ 12| |}
+ 13| |
+ 14| 1|fn main() {
+ 15| 1| do_not_add_coverage_1();
+ 16| 1| do_not_add_coverage_2();
+ 17| 1|}
+
diff --git a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.no_cov_func.txt b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.no_cov_func.txt
new file mode 100644
index 0000000000000..16eaf7c858c19
--- /dev/null
+++ b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.no_cov_func.txt
@@ -0,0 +1,19 @@
+ 1| |// Enables `no_coverage` on individual functions
+ 2| |
+ 3| |#[feature(no_coverage)]
+ 4| |#[no_coverage]
+ 5| |fn do_not_add_coverage_1() {
+ 6| | println!("called but not covered");
+ 7| |}
+ 8| |
+ 9| |#[no_coverage]
+ 10| |#[feature(no_coverage)]
+ 11| |fn do_not_add_coverage_2() {
+ 12| | println!("called but not covered");
+ 13| |}
+ 14| |
+ 15| 1|fn main() {
+ 16| 1| do_not_add_coverage_1();
+ 17| 1| do_not_add_coverage_2();
+ 18| 1|}
+
diff --git a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.partial_eq.txt b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.partial_eq.txt
index 4e4dde46b344b..fc26665334950 100644
--- a/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.partial_eq.txt
+++ b/src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.partial_eq.txt
@@ -2,7 +2,7 @@
2| |// structure of this test.
3| |
4| 2|#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
- ^0 ^0 ^0 ^0 ^1 ^1 ^0^0
+ ^0 ^0 ^0 ^1 ^1 ^0^0
------------------
| Unexecuted instantiation: <partial_eq::Version as core::cmp::PartialEq>::ne
------------------
diff --git a/src/test/run-make-fulldeps/coverage/issue-83601.rs b/src/test/run-make-fulldeps/coverage/issue-83601.rs
new file mode 100644
index 0000000000000..0b72a81947cc7
--- /dev/null
+++ b/src/test/run-make-fulldeps/coverage/issue-83601.rs
@@ -0,0 +1,14 @@
+// Shows that rust-lang/rust/83601 is resolved
+
+#[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);
+}
diff --git a/src/test/run-make-fulldeps/coverage/no_cov_crate.rs b/src/test/run-make-fulldeps/coverage/no_cov_crate.rs
new file mode 100644
index 0000000000000..300570db7e8f7
--- /dev/null
+++ b/src/test/run-make-fulldeps/coverage/no_cov_crate.rs
@@ -0,0 +1,17 @@
+// Enables `no_coverage` on the entire crate
+#![feature(no_coverage)]
+
+#[no_coverage]
+fn do_not_add_coverage_1() {
+ println!("called but not covered");
+}
+
+#[no_coverage]
+fn do_not_add_coverage_2() {
+ println!("called but not covered");
+}
+
+fn main() {
+ do_not_add_coverage_1();
+ do_not_add_coverage_2();
+}
diff --git a/src/test/run-make-fulldeps/coverage/no_cov_func.rs b/src/test/run-make-fulldeps/coverage/no_cov_func.rs
new file mode 100644
index 0000000000000..e19a2c4a87200
--- /dev/null
+++ b/src/test/run-make-fulldeps/coverage/no_cov_func.rs
@@ -0,0 +1,18 @@
+// Enables `no_coverage` on individual functions
+
+#[feature(no_coverage)]
+#[no_coverage]
+fn do_not_add_coverage_1() {
+ println!("called but not covered");
+}
+
+#[no_coverage]
+#[feature(no_coverage)]
+fn do_not_add_coverage_2() {
+ println!("called but not covered");
+}
+
+fn main() {
+ do_not_add_coverage_1();
+ do_not_add_coverage_2();
+}
diff --git a/src/test/ui/feature-gates/feature-gate-no_coverage.rs b/src/test/ui/feature-gates/feature-gate-no_coverage.rs
new file mode 100644
index 0000000000000..c6b79f9a43171
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-no_coverage.rs
@@ -0,0 +1,8 @@
+#![crate_type = "lib"]
+
+#[no_coverage]
+#[feature(no_coverage)] // does not have to be enabled before `#[no_coverage]`
+fn no_coverage_is_enabled_on_this_function() {}
+
+#[no_coverage] //~ ERROR the `#[no_coverage]` attribute is an experimental feature
+fn requires_feature_no_coverage() {}
diff --git a/src/test/ui/feature-gates/feature-gate-no_coverage.stderr b/src/test/ui/feature-gates/feature-gate-no_coverage.stderr
new file mode 100644
index 0000000000000..04627be4aaf65
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-no_coverage.stderr
@@ -0,0 +1,13 @@
+error[E0658]: the `#[no_coverage]` attribute is an experimental feature
+ --> $DIR/feature-gate-no_coverage.rs:7:1
+ |
+LL | #[no_coverage]
+ | ^^^^^^^^^^^^^^
+ |
+ = note: see issue #84605 <https://github.com/rust-lang/rust/issues/84605> for more information
+ = help: add `#![feature(no_coverage)]` to the crate attributes to enable
+ = help: or, alternatively, add `#[feature(no_coverage)]` to the function
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.