Merge pull request #8158 from dcbaker/submit/rust-generated-main

rust: Accept generated sources for main.rs

5 files changed, 70 insertions, 22 deletions

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index d66708c..c1c4c93 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -45,7 +45,7 @@ from ..mesonlib import (
 )
 from ..mesonlib import get_compiler_for_source, has_path_sep, OptionKey
 from .backends import CleanTrees
-from ..build import InvalidArguments
+from ..build import GeneratedList, InvalidArguments
 from ..interpreter import Interpreter
 
 if T.TYPE_CHECKING:
@@ -691,13 +691,6 @@ int dummy;
         src_block['sources'] += sources
         src_block['generated_sources'] += generated_sources
 
-    def is_rust_target(self, target):
-        if len(target.sources) > 0:
-            first_file = target.sources[0]
-            if first_file.fname.endswith('.rs'):
-                return True
-        return False
-
     def generate_target(self, target):
         try:
             if isinstance(target, build.BuildTarget):
@@ -723,7 +716,7 @@ int dummy;
         if isinstance(target, build.Jar):
             self.generate_jar_target(target)
             return
-        if self.is_rust_target(target):
+        if target.uses_rust():
             self.generate_rust_target(target)
             return
         if 'cs' in target.compilers:
@@ -1588,12 +1581,27 @@ int dummy;
         args = rustc.compiler_args()
         # Compiler args for compiling this target
         args += compilers.get_base_compile_args(base_proxy, rustc)
+        self.generate_generator_list_rules(target)
+
+        orderdeps = [os.path.join(t.subdir, t.get_filename()) for t in target.link_targets]
+
         main_rust_file = None
         for i in target.get_sources():
             if not rustc.can_compile(i):
                 raise InvalidArguments('Rust target {} contains a non-rust source file.'.format(target.get_basename()))
             if main_rust_file is None:
                 main_rust_file = i.rel_to_builddir(self.build_to_src)
+        for g in target.get_generated_sources():
+            for i in g.get_outputs():
+                if not rustc.can_compile(i):
+                    raise InvalidArguments('Rust target {} contains a non-rust source file.'.format(target.get_basename()))
+                if isinstance(g, GeneratedList):
+                    fname = os.path.join(self.get_target_private_dir(target), i)
+                else:
+                    fname = i
+                if main_rust_file is None:
+                    main_rust_file = fname
+                orderdeps.append(fname)
         if main_rust_file is None:
             raise RuntimeError('A Rust target has no Rust sources. This is weird. Also a bug. Please report')
         target_name = os.path.join(target.subdir, target.get_filename())
@@ -1631,7 +1639,6 @@ int dummy;
         args += target.get_extra_args('rust')
         args += rustc.get_output_args(os.path.join(target.subdir, target.get_filename()))
         args += self.environment.coredata.get_external_args(target.for_machine, rustc.language)
-        orderdeps = [os.path.join(t.subdir, t.get_filename()) for t in target.link_targets]
         linkdirs = OrderedDict()
         for d in target.link_targets:
             linkdirs[d.subdir] = True
@@ -1678,7 +1685,7 @@ int dummy;
                 args += ['-C', 'link-arg=' + rpath_arg + ':' + os.path.join(rustc.get_sysroot(), 'lib')]
         compiler_name = self.get_compiler_rule_name('rust', target.for_machine)
         element = NinjaBuildElement(self.all_outputs, target_name, compiler_name, main_rust_file)
-        if len(orderdeps) > 0:
+        if orderdeps:
             element.add_orderdep(orderdeps)
         element.add_item('ARGS', args)
         element.add_item('targetdep', depfile)
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index 017b0f0..13783d1 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -569,7 +569,7 @@ class BuildTarget(Target):
         unity_opt = environment.coredata.get_option(OptionKey('unity'))
         self.is_unity = unity_opt == 'on' or (unity_opt == 'subprojects' and subproject != '')
         self.environment = environment
-        self.sources = []
+        self.sources: T.List[File] = []
         self.compilers = OrderedDict() # type: OrderedDict[str, Compiler]
         self.objects = []
         self.external_deps = []
@@ -588,7 +588,7 @@ class BuildTarget(Target):
         self.need_install = False
         self.pch = {}
         self.extra_args: T.Dict[str, T.List['FileOrString']] = {}
-        self.generated = []
+        self.generated: T.Sequence[T.Union[GeneratedList, CustomTarget, CustomTargetIndex]] = []
         self.d_features = {}
         self.pic = False
         self.pie = False
@@ -1412,9 +1412,16 @@ You probably should put it in link_with instead.''')
         m = 'Could not get a dynamic linker for build target {!r}'
         raise AssertionError(m.format(self.name))
 
-    def get_using_rustc(self) -> bool:
+    def uses_rust(self) -> bool:
         """Is this target a rust target."""
-        return self.sources and self.sources[0].fname.endswith('.rs')
+        if self.sources:
+            first_file = self.sources[0]
+            if first_file.fname.endswith('.rs'):
+                return True
+        elif self.generated:
+            if self.generated[0].get_outputs()[0].endswith('.rs'):
+                return True
+        return False
 
     def get_using_msvc(self):
         '''
@@ -1434,11 +1441,13 @@ You probably should put it in link_with instead.''')
         2. If the target contains only objects, process_compilers guesses and
            picks the first compiler that smells right.
         '''
-        compiler, _ = self.get_clink_dynamic_linker_and_stdlibs()
+        # Rustc can use msvc style linkers
+        if self.uses_rust():
+            compiler = self.environment.coredata.compilers[self.for_machine]['rust']
+        else:
+            compiler, _ = self.get_clink_dynamic_linker_and_stdlibs()
         # Mixing many languages with MSVC is not supported yet so ignore stdlibs.
-        if compiler and compiler.get_linker_id() in {'link', 'lld-link', 'xilink', 'optlink'}:
-            return True
-        return False
+        return compiler and compiler.get_linker_id() in {'link', 'lld-link', 'xilink', 'optlink'}
 
     def check_module_linking(self):
         '''
@@ -1687,7 +1696,7 @@ class Executable(BuildTarget):
                     self.import_filename = self.gcc_import_filename
 
         if m.is_windows() and ('cs' in self.compilers or
-                               self.get_using_rustc() or
+                               self.uses_rust() or
                                self.get_using_msvc()):
             self.debug_filename = self.name + '.pdb'
 
@@ -1877,7 +1886,7 @@ class SharedLibrary(BuildTarget):
             suffix = 'dll'
             self.vs_import_filename = '{0}{1}.lib'.format(self.prefix if self.prefix is not None else '', self.name)
             self.gcc_import_filename = '{0}{1}.dll.a'.format(self.prefix if self.prefix is not None else 'lib', self.name)
-            if self.get_using_rustc():
+            if self.uses_rust():
                 # Shared library is of the form foo.dll
                 prefix = ''
                 # Import library is called foo.dll.lib
diff --git a/mesonbuild/modules/unstable_rust.py b/mesonbuild/modules/unstable_rust.py
index 02369b6..d215376 100644
--- a/mesonbuild/modules/unstable_rust.py
+++ b/mesonbuild/modules/unstable_rust.py
@@ -85,7 +85,7 @@ class RustModule(ExtensionModule):
         base_target: BuildTarget = unholder(args[1])
         if not isinstance(base_target, BuildTarget):
             raise InterpreterException('Second positional argument to rustmod.test() must be a library or executable')
-        if not base_target.get_using_rustc():
+        if not base_target.uses_rust():
             raise InterpreterException('Second positional argument to rustmod.test() must be a rust based target')
         extra_args = stringlistify(kwargs.get('args', []))
 
diff --git a/test cases/rust/11 generated main/gen.py b/test cases/rust/11 generated main/gen.py
new file mode 100644
index 0000000..ebbc2a7
--- /dev/null
+++ b/test cases/rust/11 generated main/gen.py
@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+
+import argparse
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    parser.add_argument('out')
+    args = parser.parse_args()
+
+    with open(args.out, 'w') as f:
+        f.write('fn main() { println!("I prefer tarnish, actually.") }')
+
+
+if __name__ == "__main__":
+    main()
diff --git a/test cases/rust/11 generated main/meson.build b/test cases/rust/11 generated main/meson.build
new file mode 100644
index 0000000..4749816
--- /dev/null
+++ b/test cases/rust/11 generated main/meson.build
@@ -0,0 +1,16 @@
+project('generated rust main', 'rust')
+
+gen = find_program('gen.py')
+
+c = custom_target(
+  'custom_target',
+  command : [gen, '@OUTPUT@'],
+  output : ['main.rs'],
+)
+
+executable('custom_target_main', c)
+executable('custom_target_index_main', c[0])
+
+gen = generator(gen, arguments : ['@OUTPUT@'], output : '@BASENAME@.rs')
+# Doesn't actually use gen.py as input, just a limitation of generators
+executable('generator_main', gen.process(['gen.py']))