Per machine do 'build.' and '' option prefixes

See the docs/ changes for details.

docs/markdown/Builtin-options.md

@@ -52,31 +52,36 @@ on Linux platforms.
 
 ### Core options
 
-Options that have a separate cross option will be prefixed with
-cross\_, for example, "cross_pkg_config_path" controls the paths
-pkg-config will search for host dependencies in a cross compile.
-They have no effect when the host and build machines are the same.
-
-
-| Option                               | Default value | Description                                                    | Has Separate cross |
-| ------                               | ------------- | -----------                                                    | ------------------ |
-| auto_features {enabled, disabled, auto} | auto       | Override value of all 'auto' features                          | no                 |
-| backend {ninja, vs,<br>vs2010, vs2015, vs2017, xcode} | ninja | Backend to use                                        | no                 |
-| buildtype {plain, debug,<br>debugoptimized, release, minsize, custom} | debug |  Build type to use                    | no                 |
-| debug                                | true          | Debug                                                          | no                 |
-| default_library {shared, static, both} | shared      | Default library type                                           | no                 |
-| errorlogs                            | true          | Whether to print the logs from failing tests.                  | no                 |
-| install_umask {preserve, 0000-0777}  | 022           | Default umask to apply on permissions of installed files       | no                 |
-| layout {mirror,flat}                 | mirror        | Build directory layout                                         | no                 |
-| optimization {0, g, 1, 2, 3, s}      | 0             | Optimization level                                             | no                 |
-| pkg_config_path                      | []            | Additional paths for pkg-config to search before builtin paths | yes                |
-| cmake_prefix_path                    | []            | Additional prefixes for cmake to search before builtin paths   | yes                |
-| stdsplit                             | true          | Split stdout and stderr in test logs                           | no                 |
-| strip                                | false         | Strip targets on install                                       | no                 |
-| unity {on, off, subprojects}         | off           | Unity build                                                    | no                 |
-| warning_level {0, 1, 2, 3}           | 1             | Set the warning level. From 0 = none to 3 = highest            | no                 |
-| werror                               | false         | Treat warnings as errors                                       | no                 |
-| wrap_mode {default, nofallback,<br>nodownload, forcefallback} | default | Wrap mode to use                            | no                 |
+Options that are labled "per machine" in the table are set per machine.
+Prefixing the option with `build.` just affects the build machine configuration,
+while unprefixed just affects the host machine configuration, respectively.
+Using the option as-is with no prefix affects all machines. For example:
+
+ - `build.pkg_config_path` controls the paths pkg-config will search for just
+   `native: true` dependencies (build machine).
+
+ - `pkg_config_path` controls the paths pkg-config will search for just
+   `native: false` dependencies (host machine).
+
+| Option                               | Default value | Description                                                    | Is per machine |
+| ------                               | ------------- | -----------                                                    | -------------- |
+| auto_features {enabled, disabled, auto} | auto       | Override value of all 'auto' features                          | no             |
+| backend {ninja, vs,<br>vs2010, vs2015, vs2017, xcode} | ninja | Backend to use                                        | no             |
+| buildtype {plain, debug,<br>debugoptimized, release, minsize, custom} | debug |  Build type to use                    | no             |
+| debug                                | true          | Debug                                                          | no             |
+| default_library {shared, static, both} | shared      | Default library type                                           | no             |
+| errorlogs                            | true          | Whether to print the logs from failing tests.                  | no             |
+| install_umask {preserve, 0000-0777}  | 022           | Default umask to apply on permissions of installed files       | no             |
+| layout {mirror,flat}                 | mirror        | Build directory layout                                         | no             |
+| optimization {0, g, 1, 2, 3, s}      | 0             | Optimization level                                             | no             |
+| pkg_config_path {OS separated path}  | ''            | Additional paths for pkg-config to search before builtin paths | yes            |
+| cmake_prefix_path                    | []            | Additional prefixes for cmake to search before builtin paths   | yes            |
+| stdsplit                             | true          | Split stdout and stderr in test logs                           | no             |
+| strip                                | false         | Strip targets on install                                       | no             |
+| unity {on, off, subprojects}         | off           | Unity build                                                    | no             |
+| warning_level {0, 1, 2, 3}           | 1             | Set the warning level. From 0 = none to 3 = highest            | no             |
+| werror                               | false         | Treat warnings as errors                                       | no             |
+| wrap_mode {default, nofallback,<br>nodownload, forcefallback} | default | Wrap mode to use                            | no             |
 
 ## Base options
 

docs/markdown/snippets/per-machine-options.md

@@ -0,0 +1,15 @@
+## Specifying options per mer machine
+
+Previously, no cross builds were controllable from the command line.
+Machine-specific options like the pkg-config path and compiler options only
+affected native targets, that is to say all targets in native builds, and
+`native: true` targets in cross builds. Now, prefix the option with `build.` to
+affect build machine targets, and leave it unprefixed to affect host machine
+targets.
+
+For those trying to ensure native and cross builds to the same platform produced
+the same result, the old way was frustrating because very different invocations
+were needed to affect the same targets, if it was possible at all. Now, the same
+command line arguments affect the same targets everwhere --- Meson is closer to
+ignoring whether the "overall" build is native or cross, and just caring about
+whether individual targets are for the build or host machines.

mesonbuild/coredata.py

@@ -26,7 +26,9 @@ from .wrap import WrapMode
 import ast
 import argparse
 import configparser
-from typing import Optional, Any, TypeVar, Generic, Type, List, Union
+from typing import (
+    Any, Dict, Generic, Iterable, List, Optional, Type, TypeVar, Union
+)
 import typing
 import enum
 
@@ -275,20 +277,16 @@ class DependencyCache:
     successfully lookup by providing a simple get/put interface.
     """
 
-    def __init__(self, builtins: typing.Dict[str, UserOption[typing.Any]], cross: bool):
+    def __init__(self, builtins_per_machine: PerMachine[typing.Dict[str, UserOption[typing.Any]]], for_machine: MachineChoice):
         self.__cache = OrderedDict()  # type: typing.MutableMapping[CacheKeyType, DependencySubCache]
-        self.__builtins = builtins
-        self.__is_cross = cross
+        self.__builtins_per_machine = builtins_per_machine
+        self.__for_machine = for_machine
 
     def __calculate_subkey(self, type_: DependencyCacheType) -> typing.Tuple[typing.Any, ...]:
         if type_ is DependencyCacheType.PKG_CONFIG:
-            if self.__is_cross:
-                return tuple(self.__builtins['cross_pkg_config_path'].value)
-            return tuple(self.__builtins['pkg_config_path'].value)
+            return tuple(self.__builtins_per_machine[self.__for_machine]['pkg_config_path'].value)
         elif type_ is DependencyCacheType.CMAKE:
-            if self.__is_cross:
-                return tuple(self.__builtins['cross_cmake_prefix_path'].value)
-            return tuple(self.__builtins['cmake_prefix_path'].value)
+            return tuple(self.__builtins_per_machine[self.__for_machine]['cmake_prefix_path'].value)
         assert type_ is DependencyCacheType.OTHER, 'Someone forgot to update subkey calculations for a new type'
         return tuple()
 
@@ -339,6 +337,9 @@ class DependencyCache:
     def clear(self) -> None:
         self.__cache.clear()
 
+# Can't bind this near the class method it seems, sadly.
+_V = TypeVar('_V')
+
 # This class contains all data that must persist over multiple
 # invocations of Meson. It is roughly the same thing as
 # cmakecache.
@@ -359,19 +360,16 @@ class CoreData:
         self.target_guids = {}
         self.version = version
         self.init_builtins()
-        self.backend_options = {}
-        self.user_options = {}
+        self.backend_options = {} # : Dict[str, UserOption]
+        self.user_options = {} # : Dict[str, UserOption]
         self.compiler_options = PerMachine({}, {})
-        self.base_options = {}
+        self.base_options = {} # : Dict[str, UserOption]
         self.cross_files = self.__load_config_files(options.cross_file, 'cross')
         self.compilers = OrderedDict()
         self.cross_compilers = OrderedDict()
 
-        build_cache = DependencyCache(self.builtins, False)
-        if self.cross_files:
-            host_cache = DependencyCache(self.builtins, True)
-        else:
-            host_cache = build_cache
+        build_cache = DependencyCache(self.builtins_per_machine, MachineChoice.BUILD)
+        host_cache = DependencyCache(self.builtins_per_machine, MachineChoice.BUILD)
         self.deps = PerMachine(build_cache, host_cache)  # type: PerMachine[DependencyCache]
 
         self.compiler_check_cache = OrderedDict()
@@ -462,8 +460,10 @@ class CoreData:
         self.builtins = {}
         for key, opt in builtin_options.items():
             self.builtins[key] = opt.init_option()
-            if opt.separate_cross:
-                self.builtins['cross_' + key] = opt.init_option()
+        self.builtins_per_machine = PerMachine({}, {})
+        for for_machine in iter(MachineChoice):
+            for key, opt in builtin_options_per_machine.items():
+                self.builtins_per_machine[for_machine][key] = opt.init_option()
 
     def init_backend_options(self, backend_name):
         if backend_name == 'ninja':
@@ -479,28 +479,40 @@ class CoreData:
                     '')
 
     def get_builtin_option(self, optname):
-        if optname in self.builtins:
-            v = self.builtins[optname]
+        for opts in self._get_all_builtin_options():
+            v = opts.get(optname)
+            if v is None:
+                continue
             if optname == 'wrap_mode':
                 return WrapMode.from_string(v.value)
             return v.value
         raise RuntimeError('Tried to get unknown builtin option %s.' % optname)
 
-    def set_builtin_option(self, optname, value):
-        if optname == 'prefix':
-            value = self.sanitize_prefix(value)
-        elif optname in self.builtins:
-            prefix = self.builtins['prefix'].value
-            value = self.sanitize_dir_option_value(prefix, optname, value)
+    def _try_set_builtin_option(self, optname, value):
+        for opts in self._get_all_builtin_options():
+            opt = opts.get(optname)
+            if opt is None:
+                continue
+            if optname == 'prefix':
+                value = self.sanitize_prefix(value)
+            else:
+                prefix = self.builtins['prefix'].value
+                value = self.sanitize_dir_option_value(prefix, optname, value)
+            break
         else:
-            raise RuntimeError('Tried to set unknown builtin option %s.' % optname)
-        self.builtins[optname].set_value(value)
-
+            return False
+        opt.set_value(value)
         # Make sure that buildtype matches other settings.
         if optname == 'buildtype':
             self.set_others_from_buildtype(value)
         else:
             self.set_buildtype_from_others()
+        return True
+
+    def set_builtin_option(self, optname, value):
+        res = self._try_set_builtin_option(optname, value)
+        if not res:
+            raise RuntimeError('Tried to set unknown builtin option %s.' % optname)
 
     def set_others_from_buildtype(self, value):
         if value == 'plain':
@@ -541,29 +553,42 @@ class CoreData:
             mode = 'custom'
         self.builtins['buildtype'].set_value(mode)
 
-    def get_all_compiler_options(self):
-        # TODO think about cross and command-line interface. (Only .build is mentioned here.)
-        yield self.compiler_options.build
-
-    def _get_all_nonbuiltin_options(self):
+    @staticmethod
+    def get_prefixed_options_per_machine(
+        options_per_machine # : PerMachine[Dict[str, _V]]]
+    ) -> Iterable[Dict[str, _V]]:
+        for for_machine in iter(MachineChoice):
+            prefix = for_machine.get_prefix()
+            yield {
+                prefix + k: v
+                for k, v in options_per_machine[for_machine].items()
+            }
+
+    def _get_all_nonbuiltin_options(self) -> Iterable[Dict[str, UserOption]]:
         yield self.backend_options
         yield self.user_options
-        yield from self.get_all_compiler_options()
+        yield from self.get_prefixed_options_per_machine(self.compiler_options)
         yield self.base_options
 
-    def get_all_options(self):
-        return chain([self.builtins], self._get_all_nonbuiltin_options())
+    def _get_all_builtin_options(self) -> Dict[str, UserOption]:
+        yield from self.get_prefixed_options_per_machine(self.builtins_per_machine)
+        yield self.builtins
+
+    def get_all_options(self) -> Dict[str, UserOption]:
+        yield from self._get_all_nonbuiltin_options()
+        yield from self._get_all_builtin_options()
 
     def validate_option_value(self, option_name, override_value):
         for opts in self.get_all_options():
-            if option_name in opts:
-                opt = opts[option_name]
+            opt = opts.get(option_name)
+            if opt is not None:
                 try:
                     return opt.validate_value(override_value)
                 except MesonException as e:
                     raise type(e)(('Validation failed for option %s: ' % option_name) + str(e)) \
                         .with_traceback(sys.exc_into()[2])
-        raise MesonException('Tried to validate unknown option %s.' % option_name)
+        else:
+            raise MesonException('Tried to validate unknown option %s.' % option_name)
 
     def get_external_args(self, for_machine: MachineChoice, lang):
         return self.compiler_options[for_machine][lang + '_args'].value
@@ -593,17 +618,17 @@ class CoreData:
         unknown_options = []
         for k, v in options.items():
             if k == 'prefix':
-                pass
-            elif k in self.builtins:
-                self.set_builtin_option(k, v)
+                continue
+            if self._try_set_builtin_option(k, v):
+                continue
+            for opts in self._get_all_nonbuiltin_options():
+                tgt = opts.get(k)
+                if tgt is None:
+                    continue
+                tgt.set_value(v)
+                break
             else:
-                for opts in self._get_all_nonbuiltin_options():
-                    if k in opts:
-                        tgt = opts[k]
-                        tgt.set_value(v)
-                        break
-                else:
-                    unknown_options.append(k)
+                unknown_options.append(k)
         if unknown_options and warn_unknown:
             unknown_options = ', '.join(sorted(unknown_options))
             sub = 'In subproject {}: '.format(subproject) if subproject else ''
@@ -645,7 +670,9 @@ class CoreData:
             if subproject:
                 if not k.startswith(subproject + ':'):
                     continue
-            elif k not in builtin_options:
+            elif k not in builtin_options.keys() \
+                    and 'build.' + k not in builtin_options_per_machine.keys() \
+                    and k not in builtin_options_per_machine.keys():
                 if ':' in k:
                     continue
                 if optinterpreter.is_invalid_name(k, log=False):
@@ -666,7 +693,7 @@ class CoreData:
         if cross_comp is not None:
             new_options_for_host = cross_comp.get_and_default_options(env.properties.host)
         else:
-            new_options_for_host = new_options_for_build
+            new_options_for_host = comp.get_and_default_options(env.properties.host)
 
         opts_machines_list = [
             (new_options_for_build, MachineChoice.BUILD),
@@ -678,10 +705,10 @@ class CoreData:
             for k, o in new_options.items():
                 if not k.startswith(optprefix):
                     raise MesonException('Internal error, %s has incorrect prefix.' % k)
-                if (env.machines.matches_build_machine(for_machine) and
-                        k in env.cmd_line_options):
-                    # TODO think about cross and command-line interface.
-                    o.set_value(env.cmd_line_options[k])
+                # prefixed compiler options affect just this machine
+                opt_prefix = for_machine.get_prefix()
+                if opt_prefix + k in env.cmd_line_options:
+                    o.set_value(env.cmd_line_options[opt_prefix + k])
                 self.compiler_options[for_machine].setdefault(k, o)
 
         enabled_opts = []
@@ -794,7 +821,10 @@ def save(obj, build_dir):
 
 def register_builtin_arguments(parser):
     for n, b in builtin_options.items():
-        b.add_to_argparse(n, parser)
+        b.add_to_argparse(n, parser, '', '')
+    for n, b in builtin_options_per_machine.items():
+        b.add_to_argparse(n, parser, '', ' (just for host machine)')
+        b.add_to_argparse(n, parser, 'build.', ' (just for build machine)')
     parser.add_argument('-D', action='append', dest='projectoptions', default=[], metavar="option",
                         help='Set the value of an option, can be used several times to set multiple options.')
 
@@ -812,19 +842,19 @@ def parse_cmd_line_options(args):
     args.cmd_line_options = create_options_dict(args.projectoptions)
 
     # Merge builtin options set with --option into the dict.
-    for name, builtin in builtin_options.items():
-        names = [name]
-        if builtin.separate_cross:
-            names.append('cross_' + name)
-        for name in names:
-            value = getattr(args, name, None)
-            if value is not None:
-                if name in args.cmd_line_options:
-                    cmdline_name = BuiltinOption.argparse_name_to_arg(name)
-                    raise MesonException(
-                        'Got argument {0} as both -D{0} and {1}. Pick one.'.format(name, cmdline_name))
-                args.cmd_line_options[name] = value
-                delattr(args, name)
+    for name in chain(
+            builtin_options.keys(),
+            ('build.' + k for k in builtin_options_per_machine.keys()),
+            builtin_options_per_machine.keys(),
+    ):
+        value = getattr(args, name, None)
+        if value is not None:
+            if name in args.cmd_line_options:
+                cmdline_name = BuiltinOption.argparse_name_to_arg(name)
+                raise MesonException(
+                    'Got argument {0} as both -D{0} and {1}. Pick one.'.format(name, cmdline_name))
+            args.cmd_line_options[name] = value
+            delattr(args, name)
 
 
 _U = TypeVar('_U', bound=UserOption[_T])
@@ -837,13 +867,12 @@ class BuiltinOption(Generic[_T, _U]):
     """
 
     def __init__(self, opt_type: Type[_U], description: str, default: Any, yielding: Optional[bool] = None, *,
-                 choices: Any = None, separate_cross: bool = False):
+                 choices: Any = None):
         self.opt_type = opt_type
         self.description = description
         self.default = default
         self.choices = choices
         self.yielding = yielding
-        self.separate_cross = separate_cross
 
     def init_option(self) -> _U:
         """Create an instance of opt_type and return it."""
@@ -882,7 +911,7 @@ class BuiltinOption(Generic[_T, _U]):
             pass
         return self.default
 
-    def add_to_argparse(self, name: str, parser: argparse.ArgumentParser) -> None:
+    def add_to_argparse(self, name: str, parser: argparse.ArgumentParser, prefix: str, help_suffix: str) -> None:
         kwargs = {}
 
         c = self._argparse_choices()
@@ -895,13 +924,10 @@ class BuiltinOption(Generic[_T, _U]):
         if c and not b:
             kwargs['choices'] = c
         kwargs['default'] = argparse.SUPPRESS
-        kwargs['dest'] = name
+        kwargs['dest'] = prefix + name
 
-        cmdline_name = self.argparse_name_to_arg(name)
-        parser.add_argument(cmdline_name, help=h, **kwargs)
-        if self.separate_cross:
-            kwargs['dest'] = 'cross_' + name
-            parser.add_argument(self.argparse_name_to_arg('cross_' + name), help=h + ' (for host in cross compiles)', **kwargs)
+        cmdline_name = self.argparse_name_to_arg(prefix + name)
+        parser.add_argument(cmdline_name, help=h + help_suffix, **kwargs)
 
 # Update `docs/markdown/Builtin-options.md` after changing the options below
 builtin_options = OrderedDict([
@@ -929,8 +955,6 @@ builtin_options = OrderedDict([
     ('errorlogs',       BuiltinOption(UserBooleanOption, "Whether to print the logs from failing tests", True)),
     ('install_umask',   BuiltinOption(UserUmaskOption, 'Default umask to apply on permissions of installed files', '022')),
     ('layout',          BuiltinOption(UserComboOption, 'Build directory layout', 'mirror', choices=['mirror', 'flat'])),
-    ('pkg_config_path', BuiltinOption(UserArrayOption, 'List of additional paths for pkg-config to search', [], separate_cross=True)),
-    ('cmake_prefix_path', BuiltinOption(UserArrayOption, 'List of additional prefixes for cmake to search', [], separate_cross=True)),
     ('optimization',    BuiltinOption(UserComboOption, 'Optimization level', '0', choices=['0', 'g', '1', '2', '3', 's'])),
     ('stdsplit',        BuiltinOption(UserBooleanOption, 'Split stdout and stderr in test logs', True)),
     ('strip',           BuiltinOption(UserBooleanOption, 'Strip targets on install', False)),
@@ -940,6 +964,11 @@ builtin_options = OrderedDict([
     ('wrap_mode',       BuiltinOption(UserComboOption, 'Wrap mode', 'default', choices=['default', 'nofallback', 'nodownload', 'forcefallback'])),
 ])
 
+builtin_options_per_machine = OrderedDict([
+    ('pkg_config_path', BuiltinOption(UserArrayOption, 'List of additional paths for pkg-config to search', [])),
+    ('cmake_prefix_path', BuiltinOption(UserArrayOption, 'List of additional prefixes for cmake to search', [])),
+])
+
 # Special prefix-dependent defaults for installation directories that reside in
 # a path outside of the prefix in FHS and common usage.
 builtin_dir_noprefix_options = {

mesonbuild/dependencies/base.py

@@ -665,11 +665,12 @@ class PkgConfigDependency(ExternalDependency):
         else:
             env = env.copy()
 
-        if self.want_cross:
-            extra_paths = self.env.coredata.get_builtin_option('cross_pkg_config_path')
+        if not self.want_cross and self.env.is_cross_build():
+            for_machine = MachineChoice.BUILD
         else:
-            extra_paths = self.env.coredata.get_builtin_option('pkg_config_path')
+            for_machine = MachineChoice.HOST
 
+        extra_paths = self.env.coredata.builtins_per_machine[for_machine]['pkg_config_path'].value
         new_pkg_config_path = ':'.join([p for p in extra_paths])
         mlog.debug('PKG_CONFIG_PATH: ' + new_pkg_config_path)
         env['PKG_CONFIG_PATH'] = new_pkg_config_path
@@ -1137,10 +1138,7 @@ class CMakeDependency(ExternalDependency):
         if cm_path:
             cm_args.append('-DCMAKE_MODULE_PATH=' + ';'.join(cm_path))
 
-        if environment.is_cross_build() and self.want_cross:
-            pref_path = self.env.coredata.builtins['cross_cmake_prefix_path'].value
-        else:
-            pref_path = self.env.coredata.builtins['cmake_prefix_path'].value
+        pref_path = self.env.coredata.builtins_per_machine[for_machine]['cmake_prefix_path'].value
         if pref_path:
             cm_args.append('-DCMAKE_PREFIX_PATH={}'.format(';'.join(pref_path)))
 

mesonbuild/interpreter.py

@@ -2097,12 +2097,12 @@ class Interpreter(InterpreterBase):
     def get_non_matching_default_options(self):
         env = self.environment
         for def_opt_name, def_opt_value in self.project_default_options.items():
-            for option_type in env.coredata.get_all_options():
-                for cur_opt_name, cur_opt_value in option_type.items():
-                    if def_opt_name == cur_opt_name:
-                        def_opt_value = env.coredata.validate_option_value(def_opt_name, def_opt_value)
-                        if def_opt_value != cur_opt_value.value:
-                            yield (def_opt_name, def_opt_value, cur_opt_value)
+            for opts in env.coredata.get_all_options():
+                cur_opt_value = opts.get(def_opt_name)
+                if cur_opt_value is not None:
+                    def_opt_value = env.coredata.validate_option_value(def_opt_name, def_opt_value)
+                    if def_opt_value != cur_opt_value.value:
+                        yield (def_opt_name, def_opt_value, cur_opt_value)
 
     def build_func_dict(self):
         self.funcs.update({'add_global_arguments': self.func_add_global_arguments,
@@ -2519,13 +2519,14 @@ external dependencies (including libraries) must go to "dependencies".''')
         return self.subprojects[dirname]
 
     def get_option_internal(self, optname):
-        for d in chain(
+        for opts in chain(
                 [self.coredata.base_options, compilers.base_options, self.coredata.builtins],
-                self.coredata.get_all_compiler_options()):
-            try:
-                return d[optname]
-            except KeyError:
-                pass
+                self.coredata.get_prefixed_options_per_machine(self.coredata.builtins_per_machine),
+                self.coredata.get_prefixed_options_per_machine(self.coredata.compiler_options),
+        ):
+            v = opts.get(optname)
+            if v is not None:
+                return v
 
         raw_optname = optname
         if self.is_subproject():

mesonbuild/mconf.py

@@ -181,10 +181,16 @@ class Conf:
         core_options = {k: o for k, o in self.coredata.builtins.items() if k in core_option_names}
 
         self.print_options('Core options', core_options)
+        self.print_options('Core options (for host machine)', self.coredata.builtins_per_machine.host)
+        self.print_options(
+            'Core options (for build machine)',
+            {'build.' + k: o for k, o in self.coredata.builtins_per_machine.build.items()})
         self.print_options('Backend options', self.coredata.backend_options)
         self.print_options('Base options', self.coredata.base_options)
-        # TODO others
-        self.print_options('Compiler options', self.coredata.compiler_options.build)
+        self.print_options('Compiler options (for host machine)', self.coredata.compiler_options.host)
+        self.print_options(
+            'Compiler options (for build machine)',
+            {'build.' + k: o for k, o in self.coredata.compiler_options.build.items()})
         self.print_options('Directories', dir_options)
         self.print_options('Project options', self.coredata.user_options)
         self.print_options('Testing options', test_options)
@@ -207,9 +213,6 @@ def run(options):
         save = False
         if len(options.cmd_line_options) > 0:
             c.set_options(options.cmd_line_options)
-            if not c.build.environment.is_cross_build():
-                # TODO think about cross and command-line interface.
-                c.coredata.compiler_options.host = c.coredata.compiler_options.build
             coredata.update_cmd_line_file(builddir, options)
             save = True
         elif options.clearcache:

mesonbuild/mesonlib.py

@@ -323,6 +323,12 @@ class MachineChoice(OrderedEnum):
     BUILD = 0
     HOST = 1
 
+    def get_lower_case_name(self):
+        return PerMachine('build', 'host')[self]
+
+    def get_prefix(self):
+        return PerMachine('build.', '')[self]
+
 
 class PerMachine(typing.Generic[_T]):
     def __init__(self, build: _T, host: _T):
@@ -336,11 +342,7 @@ class PerMachine(typing.Generic[_T]):
         }[machine]
 
     def __setitem__(self, machine: MachineChoice, val: _T) -> None:
-        key = {
-            MachineChoice.BUILD:  'build',
-            MachineChoice.HOST:   'host',
-        }[machine]
-        setattr(self, key, val)
+        setattr(self, machine.get_lower_case_name(), val)
 
     def miss_defaulting(self) -> "PerMachineDefaultable[typing.Optional[_T]]":
         """Unset definition duplicated from their previous to None

mesonbuild/mintro.py

@@ -227,10 +227,20 @@ def list_buildoptions(coredata: cdata.CoreData) -> List[dict]:
     core_options = {k: o for k, o in coredata.builtins.items() if k in core_option_names}
 
     add_keys(optlist, core_options, 'core')
+    add_keys(optlist, coredata.builtins_per_machine.host, 'core (for host machine)')
+    add_keys(
+        optlist,
+        {'build.' + k: o for k, o in coredata.builtins_per_machine.build.items()},
+        'core (for build machine)',
+    )
     add_keys(optlist, coredata.backend_options, 'backend')
     add_keys(optlist, coredata.base_options, 'base')
-    # TODO others
-    add_keys(optlist, coredata.compiler_options.build, 'compiler')
+    add_keys(optlist, coredata.compiler_options.host, 'compiler (for host machine)')
+    add_keys(
+        optlist,
+        {'build.' + k: o for k, o in coredata.compiler_options.build.items()},
+        'compiler (for build machine)',
+    )
     add_keys(optlist, dir_options, 'directory')
     add_keys(optlist, coredata.user_options, 'user')
     add_keys(optlist, test_options, 'test')

mesonbuild/rewriter.py

@@ -465,10 +465,13 @@ class Rewriter:
         cdata = self.interpreter.coredata
         options = {
             **cdata.builtins,
+            **cdata.builtins_per_machine.host,
+            **{'build.' + k: o for k, o in cdata.builtins_per_machine.build.items()},
             **cdata.backend_options,
             **cdata.base_options,
-            **cdata.compiler_options.build,
-            **cdata.user_options
+            **cdata.compiler_options.host,
+            **{'build.' + k: o for k, o in cdata.compiler_options.build.items()},
+            **cdata.user_options,
         }
 
         for key, val in sorted(cmd['options'].items()):

run_unittests.py

@@ -1088,7 +1088,10 @@ class DataTests(unittest.TestCase):
                         found_entries |= arches
             break
 
-        self.assertEqual(found_entries, set(mesonbuild.coredata.builtin_options.keys()))
+        self.assertEqual(found_entries, set([
+            *mesonbuild.coredata.builtin_options.keys(),
+            *mesonbuild.coredata.builtin_options_per_machine.keys()
+        ]))
 
     def test_cpu_families_documented(self):
         with open("docs/markdown/Reference-tables.md") as f:
@@ -5193,8 +5196,7 @@ endian = 'little'
     @skipIfNoPkgconfig
     def test_pkg_config_option(self):
         testdir = os.path.join(self.unit_test_dir, '55 pkg_config_path option')
-        self.init(testdir, extra_args=['-Dpkg_config_path=' + os.path.join(testdir, 'extra_path')])
-
+        self.init(testdir, extra_args=['-Dpkg_config_path=' + os.path.join(testdir, 'host_extra_path')])
 
 def should_run_cross_arm_tests():
     return shutil.which('arm-linux-gnueabihf-gcc') and not platform.machine().lower().startswith('arm')
@@ -5294,7 +5296,10 @@ class LinuxCrossMingwTests(BasePlatformTests):
     @skipIfNoPkgconfig
     def test_cross_pkg_config_option(self):
         testdir = os.path.join(self.unit_test_dir, '55 pkg_config_path option')
-        self.init(testdir, extra_args=['-Dcross_pkg_config_path=' + os.path.join(testdir, 'extra_path')])
+        self.init(testdir, extra_args=[
+            '-Dbuild.pkg_config_path=' + os.path.join(testdir, 'build_extra_path'),
+            '-Dpkg_config_path=' + os.path.join(testdir, 'host_extra_path'),
+        ])
 
 
 class PythonTests(BasePlatformTests):

test cases/unit/55 pkg_config_path option/build_extra_path/totally_made_up_dep.pc

@@ -0,0 +1,7 @@
+prefix=/
+libdir=${prefix}/lib
+includedir=${prefix}/include
+
+Name: totally_made_up_dep
+Description: completely and totally made up for a test case
+Version: 4.5.6

test cases/unit/55 pkg_config_path option/meson.build

@@ -1,3 +1,12 @@
 project('pkg_config_path option')
 
-dependency('totally_made_up_dep', method : 'pkg-config')
+build = dependency('totally_made_up_dep', native: true, method : 'pkg-config')
+host = dependency('totally_made_up_dep', native: false, method : 'pkg-config')
+
+# TODO always test we can do this separately
+if meson.is_cross_build()
+   assert(build.version() == '4.5.6', 'wrong version for build machine dependency')
+else
+   assert(host.version() == '1.2.3', 'wrong version for host machine dependency')
+endif
+assert(host.version() == '1.2.3', 'wrong version for host machine dependency')