Change the documented implicit value of -C instrument-coverage to =yes

compiler/rustc_interface/src/tests.rs

@@ -590,7 +590,7 @@ macro_rules! tracked {
     tracked!(force_frame_pointers, Some(false));
     tracked!(force_unwind_tables, Some(true));
     tracked!(inline_threshold, Some(0xf007ba11));
-    tracked!(instrument_coverage, InstrumentCoverage::All);
+    tracked!(instrument_coverage, InstrumentCoverage::Yes);
     tracked!(link_dead_code, Some(true));
     tracked!(linker_plugin_lto, LinkerPluginLto::LinkerPluginAuto);
     tracked!(llvm_args, vec![String::from("1"), String::from("2")]);

compiler/rustc_session/src/config.rs

@@ -146,8 +146,10 @@ pub enum LtoCli {
 /// unless the function has type parameters.
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]
 pub enum InstrumentCoverage {
-    /// Default `-C instrument-coverage` or `-C instrument-coverage=statement`
-    All,
+    /// `-C instrument-coverage=no` (or `off`, `false` etc.)
+    No,
+    /// `-C instrument-coverage` or `-C instrument-coverage=yes`
+    Yes,
     /// Additionally, instrument branches and output branch coverage.
     /// `-Zunstable-options -C instrument-coverage=branch`
     Branch,
@@ -155,8 +157,6 @@ pub enum InstrumentCoverage {
     ExceptUnusedGenerics,
     /// `-Zunstable-options -C instrument-coverage=except-unused-functions`
     ExceptUnusedFunctions,
-    /// `-C instrument-coverage=off` (or `no`, etc.)
-    Off,
 }
 
 /// Settings for `-Z instrument-xray` flag.
@@ -2722,7 +2722,7 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M
     // This is what prevents them from being used on stable compilers.
     match cg.instrument_coverage {
         // Stable values:
-        InstrumentCoverage::All | InstrumentCoverage::Off => {}
+        InstrumentCoverage::Yes | InstrumentCoverage::No => {}
         // Unstable values:
         InstrumentCoverage::Branch
         | InstrumentCoverage::ExceptUnusedFunctions
@@ -2736,7 +2736,7 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M
         }
     }
 
-    if cg.instrument_coverage != InstrumentCoverage::Off {
+    if cg.instrument_coverage != InstrumentCoverage::No {
         if cg.profile_generate.enabled() || cg.profile_use.is_some() {
             early_dcx.early_fatal(
                 "option `-C instrument-coverage` is not compatible with either `-C profile-use` \

compiler/rustc_session/src/options.rs

@@ -394,8 +394,7 @@ mod desc {
     pub const parse_linker_flavor: &str = ::rustc_target::spec::LinkerFlavorCli::one_of();
     pub const parse_optimization_fuel: &str = "crate=integer";
     pub const parse_dump_mono_stats: &str = "`markdown` (default) or `json`";
-    pub const parse_instrument_coverage: &str =
-        "`all` (default), `branch`, `except-unused-generics`, `except-unused-functions`, or `off`";
+    pub const parse_instrument_coverage: &str = "either a boolean (`yes`, `no`, `on`, `off`, etc) or (unstable) one of `branch`, `except-unused-generics`, `except-unused-functions`";
     pub 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 const parse_unpretty: &str = "`string` or `string=string`";
     pub const parse_treat_err_as_bug: &str = "either no value or a non-negative number";
@@ -918,18 +917,18 @@ pub(crate) fn parse_instrument_coverage(
         if v.is_some() {
             let mut bool_arg = false;
             if parse_bool(&mut bool_arg, v) {
-                *slot = if bool_arg { InstrumentCoverage::All } else { InstrumentCoverage::Off };
+                *slot = if bool_arg { InstrumentCoverage::Yes } else { InstrumentCoverage::No };
                 return true;
             }
         }
 
         let Some(v) = v else {
-            *slot = InstrumentCoverage::All;
+            *slot = InstrumentCoverage::Yes;
             return true;
         };
 
         *slot = match v {
-            "all" => InstrumentCoverage::All,
+            "all" => InstrumentCoverage::Yes,
             "branch" => InstrumentCoverage::Branch,
             "except-unused-generics" | "except_unused_generics" => {
                 InstrumentCoverage::ExceptUnusedGenerics
@@ -937,7 +936,7 @@ pub(crate) fn parse_instrument_coverage(
             "except-unused-functions" | "except_unused_functions" => {
                 InstrumentCoverage::ExceptUnusedFunctions
             }
-            "off" | "no" | "n" | "false" | "0" => InstrumentCoverage::Off,
+            "0" => InstrumentCoverage::No,
             _ => return false,
         };
         true
@@ -1444,15 +1443,15 @@ pub(crate) fn parse_function_return(slot: &mut FunctionReturn, v: Option<&str>)
     inline_threshold: Option<u32> = (None, parse_opt_number, [TRACKED],
         "set the threshold for inlining a function"),
     #[rustc_lint_opt_deny_field_access("use `Session::instrument_coverage` instead of this field")]
-    instrument_coverage: InstrumentCoverage = (InstrumentCoverage::Off, parse_instrument_coverage, [TRACKED],
+    instrument_coverage: InstrumentCoverage = (InstrumentCoverage::No, parse_instrument_coverage, [TRACKED],
         "instrument the generated code to support LLVM source-based code coverage \
         reports (note, the compiler build config must include `profiler = true`); \
         implies `-C symbol-mangling-version=v0`. Optional values are:
-        `=all` (implicit value)
-        `=branch`
-        `=except-unused-generics`
-        `=except-unused-functions`
-        `=off` (default)"),
+        `=no` `=n` `=off` `=false` (default)
+        `=yes` `=y` `=on` `=true` (implicit value)
+        `=branch` (unstable)
+        `=except-unused-generics` (unstable)
+        `=except-unused-functions` (unstable)"),
     link_arg: (/* redirected to link_args */) = ((), parse_string_push, [UNTRACKED],
         "a single extra argument to append to the linker invocation (can be used several times)"),
     link_args: Vec<String> = (Vec::new(), parse_list, [UNTRACKED],

compiler/rustc_session/src/session.rs

@@ -352,7 +352,7 @@ pub fn enable_internal_lints(&self) -> bool {
     }
 
     pub fn instrument_coverage(&self) -> bool {
-        self.opts.cg.instrument_coverage() != InstrumentCoverage::Off
+        self.opts.cg.instrument_coverage() != InstrumentCoverage::No
     }
 
     pub fn instrument_coverage_branch(&self) -> bool {

src/doc/rustc/src/instrument-coverage.md

@@ -331,10 +331,29 @@ $ llvm-cov report \
 
 ## `-C instrument-coverage=<options>`
 
--   `-C instrument-coverage=all`: Instrument all functions, including unused functions and unused generics. (This is the same as `-C instrument-coverage`, with no value.)
--   `-C instrument-coverage=off`: Do not instrument any functions. (This is the same as simply not including the `-C instrument-coverage` option.)
--   `-Zunstable-options -C instrument-coverage=except-unused-generics`: Instrument all functions except unused generics.
--   `-Zunstable-options -C instrument-coverage=except-unused-functions`: Instrument only used (called) functions and instantiated generic functions.
+- `-C instrument-coverage=no` (or `n`/`off`/`false`):
+  Don't enable coverage instrumentation. No functions will be instrumented for coverage.
+  - This is the same as not using the `-C instrument-coverage` flag at all.
+- `-C instrument-coverage=yes` (or `y`/`on`/`true`):
+  Enable coverage instrumentation with the default behaviour.
+  Currently this instruments all functions, including unused functions and unused generics.
+  - This is the same as `-C instrument-coverage` with no value.
+
+### Other values
+
+- `-C instrument-coverage=all`:
+  Currently an alias for `yes`, but may behave differently in the future if
+  more fine-grained coverage options are added.
+  Using this value is currently not recommended.
+
+### Unstable values
+
+- `-Z unstable-options -C instrument-coverage=branch`:
+  Placeholder for potential branch coverage support in the future.
+- `-Z unstable-options -C instrument-coverage=except-unused-generics`:
+  Instrument all functions except unused generics.
+- `-Z unstable-options -C instrument-coverage=except-unused-functions`:
+  Instrument only used (called) functions and instantiated generic functions.
 
 ## Other references
 

tests/ui/instrument-coverage/bad-value.bad.stderr

@@ -1,2 +1,2 @@
-error: incorrect value `bad-value` for codegen option `instrument-coverage` - `all` (default), `branch`, `except-unused-generics`, `except-unused-functions`, or `off` was expected
+error: incorrect value `bad-value` for codegen option `instrument-coverage` - either a boolean (`yes`, `no`, `on`, `off`, etc) or (unstable) one of `branch`, `except-unused-generics`, `except-unused-functions` was expected
 

tests/ui/instrument-coverage/bad-value.blank.stderr

@@ -1,2 +1,2 @@
-error: incorrect value `` for codegen option `instrument-coverage` - `all` (default), `branch`, `except-unused-generics`, `except-unused-functions`, or `off` was expected
+error: incorrect value `` for codegen option `instrument-coverage` - either a boolean (`yes`, `no`, `on`, `off`, etc) or (unstable) one of `branch`, `except-unused-generics`, `except-unused-functions` was expected