Add OS/2 support #14106

komh · 2025-01-10T08:44:59Z

Hi/2.

This PR is to support OS/2.

Review, please...

On OS/2, 1. a shared libary has '.dll' suffix 2. a length of DLL name should not be longer than 8 chars 3. an import library is used to link against a DLL 4. an import library has '_dll.a' suffix.

Give an user opportunities to mangle a custom short name for a DLL on OS/2.

1. Generate OMF objs with `-Zomf' compiler flags 2. Generate OMF libs with `.lib' suffix using `emxomfar' as a librarian

dcbaker

We're currently in a feature freeze, so this won't be able to land for a bit.

I've given this a first pass over, though I suspect a few iterations will be needed before this lands. Thanks for working on this

dcbaker · 2025-01-10T18:01:47Z

mesonbuild/compilers/mixins/clike.py

            for s in suffixes:
-                patterns.append(p + '{}.' + s)
+                for p in prefixes:
+                    if s.startswith('_dll.') or s.startswith('_s.'):
+                        patterns.append(p + '{}' + s)
+                    else:
+                        patterns.append(p + '{}.' + s)


This can be cleaned up a little and fold the cases together:

for s in suffixes dot = '.' if env[machines][self.for_machine].is_os2() and s.startswith(('_dll.', '_s.')) for p in prefixes: patterns.append('p + '{}' + dot + s)

edit: fixed copy/paste error in the code snippet

The last ':' of if statement is necessary?

Oh, no, that was a copy/paste error on my part. I'll edit it.

dcbaker · 2025-01-10T18:04:48Z

mesonbuild/compilers/detect.py

@@ -165,6 +168,8 @@ def detect_static_linker(env: 'Environment', compiler: Compiler) -> StaticLinker
            trials = [defaults['cuda_static_linker']] + default_linkers
        elif compiler.get_argument_syntax() == 'msvc':
            trials = [defaults['vs_static_linker'], defaults['clang_cl_static_linker']]
+        elif is_os2() and env.coredata.get_option(OptionKey('emxomf')):


Suggested change

elif is_os2() and env.coredata.get_option(OptionKey('emxomf')):

elif env.machines[compiler.for_machine].is_os2() and env.coredata.get_option(OptionKey('emxomf')):

is_os2() will give the wrong answer in a cross compile. I've been meaning to delete all of those for a while so that we have to use the Environment.machines ones, but never seem to get there.

Do you mean I should replace all is_os2() with Environment.machines ones ?

the is_os2() function is only safe to use if you know that it will always be used for the build machine, so, yes please, use Environment.machines if it's available. (There are probably some places we should use that but don't have it available, I'm fine with ignoring those because they're per-exisiting issues)

dcbaker · 2025-01-10T18:08:01Z

mesonbuild/compilers/compilers.py

+    if mesonlib.is_os2():
+        args += ['-Zomf']


These should go in the Compiler.get_always_args and Linker.get_always_args methods.

Ok, I'll try.

I'm trying to move those codes to GnuCompiler. However, I don't know how to access to the global options. How can I do that?

dcbaker · 2025-01-10T18:08:58Z

mesonbuild/build.py

+        shortname = kwargs.get('shortname')
+        if shortname:
+            self.shortname = shortname


Is there a reason you can't set this when you initially set self.shortname, like self.shortname = kwargs.get('shortname')?

No problem. Maybe I followed the coding style around.

dcbaker · 2025-01-10T18:12:33Z

mesonbuild/backend/ninjabackend.py

+                if mesonlib.is_os2():
+                    rule = '{}_DLL_LINKER{}'.format(langname, self.get_rule_suffix(for_machine))
+                    command = compiler.get_linker_exelist()
+                    args =  ['$ARGS'] + NinjaCommandArg.list(compiler.get_linker_output_args('$out'), Quoting.none) + ['$in', '$LINK_ARGS']
+                    args += ['&&', 'emximp', '-o', '$IMPLIB', '$out']
+
+                    description = 'Linking target $out'
+                    if num_pools > 0:
+                        pool = 'pool = link_pool'
+                    else:
+                        pool = None
+
+                    options = self._rsp_options(compiler)
+                    self.add_rule(NinjaRule(rule, command, args, description, **options, extra=pool))
+


It seems like you always end up using this rule for dynamic linking on OS/2 paths, am I missing something?

Yes, in order to build an import library.

So can we just have the normal shared_library linking path do this on OS/2, or is there a use of that I missed?

mesonbuild/backend/ninjabackend.py

dcbaker · 2025-01-10T18:14:25Z

mesonbuild/build.py

@@ -2167,14 +2167,16 @@ def post_init(self) -> None:
        # See our FAQ for more detailed rationale:
        # https://mesonbuild.com/FAQ.html#why-does-building-my-project-with-msvc-output-static-libraries-called-libfooa
        if not hasattr(self, 'prefix'):
-            self.prefix = 'lib'
+            self.prefix = '' if self.environment.machines[self.for_machine].is_os2() else 'lib'


Does this violate the rational for why we use 'lib as a prefix on Windows, even though that's not the standard thing to do?

If meson build system requires 'lib' prefix for a static lib, I'll do.

The comment above points to https://mesonbuild.com/FAQ.html#why-does-building-my-project-with-msvc-output-static-libraries-called-libfooa which describes the reasoning:

On Windows, we need to use .a in order to distinguish between import libraries (foo.lib) and static libraries (which we name with lib*.a to resolve the name clash).

it works well with the mingw toolchain, that can look this up on Windows using -lfoo

How does OS/2 handle this?

dcbaker · 2025-01-10T18:16:29Z

mesonbuild/build.py

@@ -112,7 +112,7 @@ class DFeatures(TypedDict):
    cs_kwargs)

 known_exe_kwargs = known_build_target_kwargs | {'implib', 'export_dynamic', 'pie', 'vs_module_defs'}
-known_shlib_kwargs = known_build_target_kwargs | {'version', 'soversion', 'vs_module_defs', 'darwin_versions', 'rust_abi'}
+known_shlib_kwargs = known_build_target_kwargs | {'version', 'soversion', 'vs_module_defs', 'darwin_versions', 'rust_abi', 'shortname'}


'shortname' needs to be added to the documentation for shared_library in the docs section.

Additionally, in interpreter/type_checking.py you need to add:

KwargInfo('shortname', (str, NoneType), since='1.8')

to the _EXCLUSIVE_SHARED_LIB_KWS list.

Ok. I'll try.

dcbaker · 2025-01-10T18:21:25Z

mesonbuild/options.py

@@ -647,6 +648,7 @@ def add_to_argparse(self, name: str, parser: argparse.ArgumentParser, help_suffi
    (OptionKey('wrap_mode'),       BuiltinOption(UserComboOption, 'Wrap mode', 'default', choices=['default', 'nofallback', 'nodownload', 'forcefallback', 'nopromote'])),
    (OptionKey('force_fallback_for'), BuiltinOption(UserArrayOption, 'Force fallback for those subprojects', [])),
    (OptionKey('vsenv'),           BuiltinOption(UserBooleanOption, 'Activate Visual Studio environment', False, readonly=True)),
+    (OptionKey('emxomf'),          BuiltinOption(UserBooleanOption, "Whether to use OMF format on OS/2", False)),


I'm not sure how I feel about configuring the object format from a global option, I need to think more about this, but it might be more appropriate as a compiler option.

I think, it would be coolI if possible to change the object format without modifying meson.build file. And it's possible to prepare compiler options depending on the global option.

komh added 12 commits January 10, 2025 16:40

Add OS2 dynamic linker support

d7d00e0

Add functions to determine if OS/2

5c7173f

Add `-Zomf' flag to a OS/2 linker

aec5af3

OS/2 linker does not support a thin archive

e9fca3e

Add a proper flag for pthread on OS/2

e297a07

PIC is always enabled on OS/2

fb8692a

Extension of the executable is `exe' on OS/2

596ee73

Remove `lib' prefix from a static library name on OS/2

3280893

Generate a shared library and an import library correctly on OS/2

47863e0

On OS/2, 1. a shared libary has '.dll' suffix 2. a length of DLL name should not be longer than 8 chars 3. an import library is used to link against a DLL 4. an import library has '_dll.a' suffix.

Add `shortname' kwarg for a short DLL name on OS/2

fce7944

Give an user opportunities to mangle a custom short name for a DLL on OS/2.

Add `emxomf' option to generate OMF files on OS/2

56e3d52

1. Generate OMF objs with `-Zomf' compiler flags 2. Generate OMF libs with `.lib' suffix using `emxomfar' as a librarian

Get library name patterns with proper prefixes and suffixes on OS/2

4ad62d7

komh requested review from dcbaker and jpakkane as code owners January 10, 2025 08:45

dcbaker requested changes Jan 10, 2025

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Add OS/2 support #14106

Add OS/2 support #14106

komh commented Jan 10, 2025

dcbaker left a comment

dcbaker Jan 10, 2025 •

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	elif is_os2() and env.coredata.get_option(OptionKey('emxomf')):
	elif env.machines[compiler.for_machine].is_os2() and env.coredata.get_option(OptionKey('emxomf')):

Add OS/2 support #14106

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dcbaker Jan 10, 2025 • edited Loading

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dcbaker Jan 10, 2025 •

edited

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