WIP: add rust support for -Db_coverage

mesonbuild/backend/ninjabackend.py

@@ -1215,6 +1215,8 @@ def generate_coverage_command(self, elem, outputs):
             if not hasattr(target, 'compilers'):
                 continue
             for compiler in target.compilers.values():
+                if compiler.get_id() == 'rustc':
+                    use_llvm_cov = True
                 if compiler.get_id() == 'clang' and not compiler.info.is_darwin():
                     use_llvm_cov = True
                     break

mesonbuild/compilers/rust.py

@@ -66,7 +66,7 @@ def __init__(self, exelist: T.List[str], version: str, for_machine: MachineChoic
                          is_cross=is_cross, full_version=full_version,
                          linker=linker)
         self.exe_wrapper = exe_wrapper
-        self.base_options.update({OptionKey(o) for o in ['b_colorout', 'b_ndebug']})
+        self.base_options.update({OptionKey(o) for o in ['b_colorout', 'b_coverage', 'b_ndebug']})
         if 'link' in self.linker.id:
             self.base_options.add(OptionKey('b_vscrt'))
         self.native_static_libs: T.List[str] = []
@@ -216,6 +216,9 @@ def get_pie_args(self) -> T.List[str]:
         # pic is on by rustc
         return []
 
+    def get_coverage_args(self) -> T.List[str]:
+        return ['-C', 'instrument-coverage']
+
     def get_assert_args(self, disable: bool) -> T.List[str]:
         action = "no" if disable else "yes"
         return ['-C', f'debug-assertions={action}', '-C', 'overflow-checks=no']