rust: add functions for coverage arguments

Adding support for linker option broke -Db_coverage because the
`--coverage` option is added to the command line without the
`-Clink-arg=` part.  Fix it by overriding get_coverage_link_args;
since we have to add the get_coverage_* functions to RustCompiler,
teach it to generate `-Cinstrument-coverage` as well.

Note that `-Clink-arg==--coverage` is actually useful only for
mixed C/Rust programs.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/mesonbuild/compilers/rust.py b/mesonbuild/compilers/rust.py
index 16700ad37..8d5a0b5dc 100644
--- a/mesonbuild/compilers/rust.py
+++ b/mesonbuild/compilers/rust.py
@@ -106,7 +106,7 @@ class RustCompiler(Compiler):
                          is_cross=is_cross, full_version=full_version,
                          linker=linker)
         self.rustup_run_and_args: T.Optional[T.Tuple[T.List[str], T.List[str]]] = get_rustup_run_and_args(exelist)
-        self.base_options.update({OptionKey(o) for o in ['b_colorout', 'b_ndebug', 'b_pgo']})
+        self.base_options.update({OptionKey(o) for o in ['b_colorout', 'b_coverage', 'b_ndebug', 'b_pgo']})
         if isinstance(self.linker, VisualStudioLikeLinkerMixin):
             self.base_options.add(OptionKey('b_vscrt'))
         self.native_static_libs: T.List[str] = []
@@ -381,6 +381,12 @@ class RustCompiler(Compiler):
     def get_lto_obj_cache_path(self, path: str) -> T.List[str]:
         return rustc_link_args(super().get_lto_obj_cache_path(path))
 
+    def get_coverage_args(self) -> T.List[str]:
+        return ['-C', 'instrument-coverage']
+
+    def get_coverage_link_args(self) -> T.List[str]:
+        return rustc_link_args(super().get_coverage_link_args())
+
     def get_profile_generate_args(self) -> T.List[str]:
         return ['-C', 'profile-generate']