ninjabackend: generate command line for rust doctests

Adjust get_rust_compiler_args() to accept the crate-type externally, because
rustdoc tests are an executable but are compiled with the parent target's
--crate-type.

Apart from that, the rustdoc arguments are very similar to the parent target, and
are handled by the same functions that were split out of generate_rust_target.

This concludes the backend implementation of doctests, only leaving the
implementation of a doctest() function in the rust module.

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

2 files changed, 24 insertions, 5 deletions

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index a3bc89c49..2faf8c1d3 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -45,6 +45,7 @@ if T.TYPE_CHECKING:
     from ..linkers.linkers import DynamicLinker, StaticLinker
     from ..compilers.cs import CsCompiler
     from ..compilers.fortran import FortranCompiler
+    from ..compilers.rust import RustCompiler
     from ..mesonlib import FileOrString
     from .backends import TargetIntrospectionData
 
@@ -1980,13 +1981,13 @@ class NinjaBackend(backends.Backend):
 
         return orderdeps, main_rust_file
 
-    def get_rust_compiler_args(self, target: build.BuildTarget, rustc: Compiler,
+    def get_rust_compiler_args(self, target: build.BuildTarget, rustc: Compiler, src_crate_type: str,
                                depfile: T.Optional[str] = None) -> T.List[str]:
         # Compiler args for compiling this target
         args = compilers.get_base_compile_args(target, rustc, self.environment)
 
         target_name = self.get_target_filename(target)
-        args.extend(['--crate-type', target.rust_crate_type])
+        args.extend(['--crate-type', src_crate_type])
 
         # If we're dynamically linking, add those arguments
         if target.rust_crate_type in {'bin', 'dylib'}:
@@ -2122,7 +2123,7 @@ class NinjaBackend(backends.Backend):
         return deps, project_deps, args
 
     def generate_rust_target(self, target: build.BuildTarget) -> None:
-        rustc = target.compilers['rust']
+        rustc = T.cast('RustCompiler', target.compilers['rust'])
         self.generate_generator_list_rules(target)
 
         for i in target.get_sources():
@@ -2141,7 +2142,7 @@ class NinjaBackend(backends.Backend):
         args = rustc.compiler_args()
 
         depfile = os.path.join(self.get_target_private_dir(target), target.name + '.d')
-        args += self.get_rust_compiler_args(target, rustc, depfile)
+        args += self.get_rust_compiler_args(target, rustc, target.rust_crate_type, depfile)
 
         deps, project_deps, deps_args = self.get_rust_compiler_deps_and_args(target, rustc)
         args += deps_args
@@ -2171,6 +2172,15 @@ class NinjaBackend(backends.Backend):
             self.generate_shsym(target)
         self.create_target_source_introspection(target, rustc, args, [main_rust_file], [])
 
+        if target.doctests:
+            assert target.doctests.target is not None
+            rustdoc = rustc.get_rustdoc(self.environment)
+            args = rustdoc.get_exe_args()
+            args += self.get_rust_compiler_args(target.doctests.target, rustdoc, target.rust_crate_type)
+            _, _, deps_args = self.get_rust_compiler_deps_and_args(target.doctests.target, rustdoc)
+            args += deps_args
+            target.doctests.cmd_args = args.to_native() + [main_rust_file] + target.doctests.cmd_args
+
     @staticmethod
     def get_rule_suffix(for_machine: MachineChoice) -> str:
         return PerMachine('_FOR_BUILD', '')[for_machine]
diff --git a/mesonbuild/compilers/rust.py b/mesonbuild/compilers/rust.py
index 17908860e..249ae1fc7 100644
--- a/mesonbuild/compilers/rust.py
+++ b/mesonbuild/compilers/rust.py
@@ -107,7 +107,7 @@ class RustCompiler(Compiler):
     def needs_static_linker(self) -> bool:
         return False
 
-    def sanity_check(self, work_dir: str, environment: 'Environment') -> None:
+    def sanity_check(self, work_dir: str, environment: Environment) -> None:
         source_name = os.path.join(work_dir, 'sanity.rs')
         output_name = os.path.join(work_dir, 'rusttest')
         cmdlist = self.exelist.copy()
@@ -333,6 +333,15 @@ class RustCompiler(Compiler):
         args = self.linker.fatal_warnings() + args
         return self.compiles('fn main { std::process::exit(0) };\n', env, extra_args=args, mode=CompileCheckMode.LINK)
 
+    @functools.lru_cache(maxsize=None)
+    def get_rustdoc(self, env: 'Environment') -> T.Optional[RustdocTestCompiler]:
+        exelist = self.get_rust_tool('rustdoc', env)
+        if not exelist:
+            return None
+
+        return RustdocTestCompiler(exelist, self.version, self.for_machine,
+                                   self.is_cross, self.info, linker=self.linker)
+
 class ClippyRustCompiler(RustCompiler):
 
     """Clippy is a linter that wraps Rustc.