New builtin-option to support partial linking for shared libraries

docs/markdown/Builtin-options.md

@@ -82,6 +82,7 @@ Using the option as-is with no prefix affects all machines. For example:
 | 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             |
+| sharedlib_linkmodel {standard, partial} | standard   | Shared library link model. standard linking or partial linking | no             |
 
 ## Base options
 

mesonbuild/backend/backends.py

@@ -607,9 +607,10 @@ def generate_basic_compiler_args(self, target, compiler, no_warn_args=False):
         # file. We want these to override all the defaults, but not the
         # per-target compile args.
         commands += self.environment.coredata.get_external_args(target.for_machine, compiler.get_language())
-        # Always set -fPIC for shared libraries
+        # Always set -fPIC for shared libraries unless partially linked
         if isinstance(target, build.SharedLibrary):
-            commands += compiler.get_pic_args()
+            if self.get_option_for_target('sharedlib_linkmodel', target) != 'partial':
+                commands += compiler.get_pic_args()
         # Set -fPIC for static libraries by default unless explicitly disabled
         if isinstance(target, build.StaticLibrary) and target.pic:
             commands += compiler.get_pic_args()

mesonbuild/backend/ninjabackend.py

@@ -2322,17 +2322,27 @@ def get_target_type_link_args(self, target, linker):
             if target.pie:
                 commands += linker.get_pie_link_args()
         elif isinstance(target, build.SharedLibrary):
+            is_linkmodel_partial = (self.get_option_for_target('sharedlib_linkmodel', target) == 'partial')
             if isinstance(target, build.SharedModule):
                 options = self.environment.coredata.base_options
                 commands += linker.get_std_shared_module_link_args(options)
             else:
-                commands += linker.get_std_shared_lib_link_args()
-            # All shared libraries are PIC
-            commands += linker.get_pic_args()
-            # Add -Wl,-soname arguments on Linux, -install_name on OS X
-            commands += linker.get_soname_args(target.prefix, target.name, target.suffix,
-                                               target.soversion, target.darwin_versions,
-                                               isinstance(target, build.SharedModule))
+                if is_linkmodel_partial:
+                    if hasattr(linker, 'get_std_partial_lib_link_args'):
+                        commands += linker.get_std_partial_lib_link_args()
+                    else:
+                        mlog.warning('The sharedlib_linkmodel option is set to partial, '
+                                     'but %s does not have support for '
+                                     'shared library partial linking' % linker.get_id())
+                else:
+                    commands += linker.get_std_shared_lib_link_args()
+            if not is_linkmodel_partial:
+                # All shared libraries are PIC
+                commands += linker.get_pic_args()
+                # Add -Wl,-soname arguments on Linux, -install_name on OS X
+                commands += linker.get_soname_args(target.prefix, target.name, target.suffix,
+                                                   target.soversion, target.darwin_versions,
+                                                   isinstance(target, build.SharedModule))
             # This is only visited when building for Windows using either GCC or Visual Studio
             if target.vs_module_defs and hasattr(linker, 'gen_vs_module_defs_args'):
                 commands += linker.gen_vs_module_defs_args(target.vs_module_defs.rel_to_builddir(self.build_to_src))

mesonbuild/compilers/compilers.py

@@ -2037,6 +2037,9 @@ def get_pch_suffix(self) -> str:
     def openmp_flags(self) -> List[str]:
         return ['-fopenmp']
 
+    def get_std_partial_lib_link_args(self):
+        return ['-Wl,-r', '-nostdlib']
+
 
 class PGICompiler:
     def __init__(self, compiler_type):
@@ -2238,6 +2241,9 @@ def get_buildtype_linker_args(self, buildtype):
     def get_std_shared_lib_link_args(self):
         return []
 
+    def get_std_partial_lib_link_args(self):
+        return ['--partial']
+
     def get_pch_suffix(self):
         return 'gch'
 
@@ -2386,7 +2392,6 @@ def openmp_flags(self):
 
 
 class ArmCompiler:
-    # Functionality that is common to all ARM family compilers.
     def __init__(self, compiler_type):
         if not self.is_cross:
             raise EnvironmentException('armcc supports only cross-compilation.')
@@ -2425,6 +2430,9 @@ def get_dependency_gen_args(self, outtarget, outfile):
     def get_std_shared_lib_link_args(self):
         return []
 
+    def get_std_partial_lib_link_args(self):
+        return ['--partial']
+
     def get_pch_use_args(self, pch_dir, header):
         # FIXME: Add required arguments
         # NOTE from armcc user guide:

mesonbuild/coredata.py

@@ -945,6 +945,7 @@ def add_to_argparse(self, name: str, parser: argparse.ArgumentParser, prefix: st
     ('warning_level',   BuiltinOption(UserComboOption, 'Compiler warning level to use', '1', choices=['0', '1', '2', '3'])),
     ('werror',          BuiltinOption(UserBooleanOption, 'Treat warnings as errors', False)),
     ('wrap_mode',       BuiltinOption(UserComboOption, 'Wrap mode', 'default', choices=['default', 'nofallback', 'nodownload', 'forcefallback'])),
+    ('sharedlib_linkmodel', BuiltinOption(UserComboOption, 'Shared library link model', 'standard', choices=['standard', 'partial'])),
 ])
 
 builtin_options_per_machine = OrderedDict([