Merge 3acf202 into d37002a

docs/yaml/functions/shared_module.yaml

@@ -15,12 +15,18 @@ description: |
 
 notes:
  - |
-   *Linking to a shared module is deprecated, and will be an error in the future*.
-   It used to be allowed because it was the only way to have a shared-library-like target that
+   *Linking to a shared module on platforms other than Android is deprecated, and will be an error
+   in the future*.
+   It was previously allowed because it was the only way to have a shared-library-like target that
    contained references to undefined symbols. However, since 0.40.0, the `override_options:`
-   [[build_target]] keyword argument can be used to create such a [[shared_library]], and shared
-   modules have other characteristics that make them incompatible with linking, such as a lack of
-   SONAME. Linking to shared modules also does not work on some platforms, such as on macOS / iOS.
+   [[build_target]] keyword argument can be used to create such a [[shared_library]] by passing
+   `override_options: 'b_lundef=false'`. Shared modules have other characteristics that make
+   them incompatible with linking, such as a lack of SONAME.
+   On macOS and iOS, linking to shared modules is disallowed by the linker, so we disallow it at
+   configure time.
+   On Android, if a shared module `foo` uses symbols from another shared module `bar`, `foo` must
+   also be linked to `bar`. Hence, linking one shared module to another will always be allowed when
+   building for Android.
 
 posargs_inherit: _build_target_base
 varargs_inherit: _build_target_base

mesonbuild/backend/ninjabackend.py

@@ -2792,7 +2792,7 @@ def get_target_type_link_args(self, target, linker):
                 commands += linker.get_std_shared_lib_link_args()
             # All shared libraries are PIC
             commands += linker.get_pic_args()
-            if not isinstance(target, build.SharedModule) or target.backwards_compat_want_soname:
+            if not isinstance(target, build.SharedModule) or target.force_soname:
                 # Add -Wl,-soname arguments on Linux, -install_name on OS X
                 commands += linker.get_soname_args(
                     self.environment, target.prefix, target.name, target.suffix,

mesonbuild/build.py

@@ -1588,10 +1588,15 @@ def check_module_linking(self):
         Warn if shared modules are linked with target: (link_with) #2865
         '''
         for link_target in self.link_targets:
-            if isinstance(link_target, SharedModule) and not link_target.backwards_compat_want_soname:
+            if isinstance(link_target, SharedModule) and not link_target.force_soname:
                 if self.environment.machines[self.for_machine].is_darwin():
                     raise MesonException(
                         f'target {self.name} links against shared module {link_target.name}. This is not permitted on OSX')
+                elif self.environment.machines[self.for_machine].is_android() and isinstance(self, SharedModule):
+                    # Android requires shared modules that use symbols from other shared modules to
+                    # be linked before they can be dlopen()ed in the correct order. Not doing so
+                    # leads to a missing symbol error: https://github.com/android/ndk/issues/201
+                    link_target.force_soname = True
                 else:
                     mlog.deprecation(f'target {self.name} links against shared module {link_target.name}, which is incorrect.'
                             '\n             '
@@ -1600,7 +1605,7 @@ def check_module_linking(self):
                             f'If shared_module() was used for {link_target.name} because it has references to undefined symbols,'
                             '\n             '
                             'use shared_libary() with `override_options: [\'b_lundef=false\']` instead.')
-                    link_target.backwards_compat_want_soname = True
+                    link_target.force_soname = True
 
 class Generator(HoldableObject):
     def __init__(self, exe: T.Union['Executable', programs.ExternalProgram],
@@ -2269,7 +2274,7 @@ def __init__(self, name, subdir, subproject, for_machine: MachineChoice, sources
         self.typename = 'shared module'
         # We need to set the soname in cases where build files link the module
         # to build targets, see: https://github.com/mesonbuild/meson/issues/9492
-        self.backwards_compat_want_soname = False
+        self.force_soname = False
 
     def get_default_install_dir(self, environment) -> T.Tuple[str, str]:
         return environment.get_shared_module_dir(), '{moduledir_shared}'