build-userland-in-tree is now a Python command

./build calls it, we did this to allow --download-dependencies to work
perfectly.

README.adoc

@@ -996,7 +996,7 @@ Build the current directory:
 ./build
 ....
 
-Note however that this would try to build the link:userland/libs/[] folder, which depends on certain libraries being installed on the host, e.g. <<blas>>.
+Note however that if you run this from link:userland/[] toplevel, it would try to build the link:userland/libs/[] folder, which depends on certain libraries being installed on the host, e.g. <<blas>>.
 
 You can install those libraries and do the build in one go with:
 
@@ -1011,7 +1011,17 @@ If you modify a dependency that is not currently considered such as a header fil
 ./build --force-rebuild
 ....
 
-Do a more clean out of tree build and run the program instead:
+The `build` scripts inside link:userland/[] are just symlinks to link:build-userland-in-tree[] which you can also use from toplevel as:
+
+....
+./build-userland-in-tree
+./build-userland-in-tree c
+./build-userland-in-tree c/hello.c
+....
+
+which is in turn just a thin wrapper around link:build-userland[], so you can use any option supported by that script freely.
+
+Do a more clean out-of-tree build and run the program instead:
 
 ....
 ./build-userland --gcc-which host --userland-build-id host

build

@@ -340,7 +340,7 @@ so looping over all of them would waste time.
                 dependencies=['buildroot'],
             ),
             'userland-host': _Component(
-                self._build_file('build-userland'),
+                self._build_file('build-userland-in-tree'),
                 apt_get_pkgs={
                     'libdrm-dev',
                     'libeigen3-dev',

build-userland

@@ -10,12 +10,12 @@ import common
 from thread_pool import ThreadPool
 
 class Main(common.BuildCliFunction):
-    def __init__(self):
+    def __init__(self, *args, **kwargs):
-        super().__init__(
+        if not 'description' in kwargs:
-            description='''\
+            kwargs['description'] = '''\
 Build our compiled userland examples.
 '''
-        )
+        super().__init__(*args, **kwargs)
         self.default_cstd = 'c11'
         self.default_cxxstd = 'c++17'
         self.add_argument(
@@ -43,10 +43,11 @@ building with the host toolchain.
 ''',
         )
         self.add_argument(
-            '--target-cwd',
+            '--target-relative-cwd',
             default=False,
             help='''\
-Treat targets as relative to the current working directory.
+Treat targets as relative to the current working directory. If the current working
+directory is outside of userland/, use userland/ instead.
 ''',
         )
         self.add_argument(
@@ -129,16 +130,23 @@ Default: build all examples that have their package dependencies met, e.g.:
                 )
         return ret
 
+    def _get_cwd(self):
+        cwd = os.path.abspath(os.getcwd())
+        if cwd.startswith(self.env['userland_source_dir']):
+            return cwd
+        else:
+            return self.env['userland_source_dir']
+
     def _get_targets(self):
         if self.env['_args_given']['targets']:
             targets = self.env['targets']
-            if self.env['target_cwd']:
+            if self.env['target_relative_cwd']:
-                cwd = os.getcwd()
+                cwd = self._get_cwd()
                 targets = [os.path.join(cwd, target) for target in targets]
             return targets
         else:
-            if self.env['target_cwd']:
+            if self.env['target_relative_cwd']:
-                return [os.getcwd()]
+                return [self._get_cwd()]
             else:
                 return [self.env['userland_source_dir']]
 

build-userland-in-tree

@@ -1,8 +1,33 @@
-#!/usr/bin/env bash
+#!/usr/bin/env python3
-"$(git rev-parse --show-toplevel)/build-userland" \
+
-  --gcc-which host \
+import imp
-  --has-all-packages \
+import os
-  --in-tree \
+import subprocess
-  --target-cwd \
+
-  "$@" \
+git_root = subprocess.check_output([
-;
+    'git',
+    'rev-parse',
+    '--show-toplevel',
+]).decode().rstrip()
+build_userland = imp.load_source(
+    'build_userland',
+    os.path.join(git_root, 'build-userland')
+)
+
+class Main(build_userland.Main):
+    def __init__(self):
+        super().__init__(
+            description='''\
+Same as build-userland, but with pre-set defaults to build in-tree
+for the native toolchain.
+''',
+            defaults={
+                'gcc_which': 'host',
+                'has_all_packages': True,
+                'in_tree': True,
+                'target_relative_cwd': True,
+            }
+        )
+
+if __name__ == '__main__':
+    Main().cli()

common.py

@@ -128,7 +128,13 @@ class LkmcCliFunction(cli_function.CliFunction):
     * command timing
     * some common flags, e.g.: --arch, --dry-run, --quiet, --verbose
     '''
-    def __init__(self, *args, defaults=None, supported_archs=None, **kwargs):
+    def __init__(
+        self,
+        *args,
+        defaults=None,
+        supported_archs=None,
+        **kwargs
+    ):
         '''
         :ptype defaults: Dict[str,Any]
         :param defaults: override the default value of an argument
@@ -958,7 +964,10 @@ lunch aosp_{}-eng
         https://stackoverflow.com/questions/2601047/import-a-python-module-without-the-py-extension
         https://stackoverflow.com/questions/31773310/what-does-the-first-argument-of-the-imp-load-source-method-do
         '''
-        return imp.load_source(basename.replace('-', '_'), os.path.join(self.env['root_dir'], basename))
+        return imp.load_source(
+            basename.replace('-', '_'),
+            os.path.join(self.env['root_dir'], basename)
+        )
 
     def import_path_main(self, path):
         '''
@@ -1112,14 +1121,6 @@ lunch aosp_{}-eng
             ]
         )
 
-    @staticmethod
-    def resolve_args(defaults, args, extra_args):
-        if extra_args is None:
-            extra_args = {}
-        argcopy = copy.copy(args)
-        argcopy.__dict__ = dict(list(defaults.items()) + list(argcopy.__dict__.items()) + list(extra_args.items()))
-        return argcopy
-
     def resolve_source(self, in_path, magic_in_dir, in_exts):
         '''
         Convert a path-like string to a source file to the full source path,