mcdc-coverage: Add mcdc and no-mcdc options for -Zcoverage-options

Author: RenjiSann

compiler/rustc_session/src/config.rs

@@ -148,6 +148,8 @@ pub enum InstrumentCoverage {
 pub struct CoverageOptions {
     /// Add branch coverage instrumentation.
     pub branch: bool,
+    /// Add MCDC coverage instrumentation.
+    pub mcdc: bool,
 }
 
 /// Settings for `-Z instrument-xray` flag.

compiler/rustc_session/src/options.rs

@@ -396,7 +396,7 @@ mod desc {
     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 = parse_bool;
-    pub const parse_coverage_options: &str = "`branch` or `no-branch`";
+    pub const parse_coverage_options: &str = "`branch`, `no-branch`, `mcdc`, `no-mcdc`";
     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";
@@ -949,6 +949,7 @@ mod parse {
             };
             let slot = match option {
                 "branch" => &mut slot.branch,
+                "mcdc" => &mut slot.mcdc,
                 _ => return false,
             };
             *slot = enabled;

compiler/rustc_session/src/session.rs

@@ -356,6 +356,10 @@ impl Session {
         self.instrument_coverage() && self.opts.unstable_opts.coverage_options.branch
     }
 
+    pub fn instrument_coverage_mcdc(&self) -> bool {
+        self.instrument_coverage() && self.opts.unstable_opts.coverage_options.mcdc
+    }
+
     pub fn is_sanitizer_cfi_enabled(&self) -> bool {
         self.opts.unstable_opts.sanitizer.contains(SanitizerSet::CFI)
     }

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

@@ -353,6 +353,8 @@ instrumentation. Pass one or more of the following values, separated by commas.
 
 - `branch` or `no-branch`
   - Enables or disables branch coverage instrumentation.
+- `mcdc` or `no-mcdc`
+  - Enables or disables MCDC coverage instrumentation.
 
 ## Other references