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

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.

2 files changed, 41 insertions, 3 deletions

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index 5fe753293..fbf6c42fc 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -2481,6 +2481,13 @@ class NinjaBackend(backends.Backend):
                 args = []
                 options = {}
                 self.add_rule(NinjaRule(rule, cmdlist, args, description, **options, extra=None))
+            if self.environment.machines[for_machine].is_os2() and complist:
+                rule = 'IMPORTLIB{}'.format(self.get_rule_suffix(for_machine))
+                description = 'Generating import library $out'
+                command = ['emximp']
+                args = ['-o', '$out', '$in']
+                options = {}
+                self.add_rule(NinjaRule(rule, command, args, description, **options, extra=None))
 
         args = self.environment.get_build_command() + \
             ['--internal',
@@ -3415,7 +3422,12 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47485'''))
         return os.path.join(targetdir, target.get_filename() + '.symbols')
 
     def generate_shsym(self, target) -> None:
-        target_file = self.get_target_filename(target)
+        # On OS/2, an import library is generated after linking a DLL, so
+        # if a DLL is used as a target, import library is not generated.
+        if self.environment.machines[target.for_machine].is_os2():
+            target_file = self.get_target_filename_for_linking(target)
+        else:
+            target_file = self.get_target_filename(target)
         if isinstance(target, build.SharedLibrary) and target.aix_so_archive:
             if self.environment.machines[target.for_machine].is_aix():
                 linker, stdlib_args = target.get_clink_dynamic_linker_and_stdlibs()
@@ -3632,6 +3644,11 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47485'''))
             linker_base = linker.get_language() # Fixme.
         if isinstance(target, build.SharedLibrary):
             self.generate_shsym(target)
+            if self.environment.machines[target.for_machine].is_os2():
+                target_file = self.get_target_filename(target)
+                import_name = self.get_import_filename(target)
+                elem = NinjaBuildElement(self.all_outputs, import_name, 'IMPORTLIB', target_file)
+                self.add_build(elem)
         crstr = self.get_rule_suffix(target.for_machine)
         linker_rule = linker_base + '_LINKER' + crstr
         # Create an empty commands list, and start adding link arguments from
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index 4721df113..2b5ec30f0 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -2494,7 +2494,7 @@ class SharedLibrary(BuildTarget):
             filename_tpl = '{0.prefix}{0.name}.{0.suffix}'
             create_debug_file = True
         # C, C++, Swift, Vala
-        # Only Windows uses a separate import library for linking
+        # Only Windows and OS/2 uses a separate import library for linking
         # For all other targets/platforms import_filename stays None
         elif self.environment.machines[self.for_machine].is_windows():
             suffix = suffix if suffix is not None else 'dll'
@@ -2553,6 +2553,19 @@ class SharedLibrary(BuildTarget):
             suffix = suffix if suffix is not None else 'so'
             # Android doesn't support shared_library versioning
             filename_tpl = '{0.prefix}{0.name}.{0.suffix}'
+        elif self.environment.machines[self.for_machine].is_os2():
+            # Shared library is of the form foo.dll
+            prefix = prefix if prefix is not None else ''
+            suffix = suffix if suffix is not None else 'dll'
+            # Import library is called foo_dll.a
+            import_suffix = import_suffix if import_suffix is not None else '_dll.a'
+            import_filename_tpl = '{0.prefix}{0.name}' + import_suffix
+            if self.soversion:
+                # fooX.dll
+                filename_tpl = '{0.prefix}{0.name}{0.soversion}.{0.suffix}'
+            else:
+                # No versioning, foo.dll
+                filename_tpl = '{0.prefix}{0.name}.{0.suffix}'
         else:
             prefix = prefix if prefix is not None else 'lib'
             suffix = suffix if suffix is not None else 'so'
@@ -2578,7 +2591,7 @@ class SharedLibrary(BuildTarget):
         which are needed while generating .so shared libraries for Linux.
 
         Besides this, there's also the import library name (self.import_filename),
-        which is only used on Windows since on that platform the linker uses a
+        which is only used on Windows and OS/2 since on that platform the linker uses a
         separate library called the "import library" during linking instead of
         the shared library (DLL).
         """
@@ -2589,6 +2602,14 @@ class SharedLibrary(BuildTarget):
             self.suffix = suffix
         self.filename_tpl = filename_tpl
         self.filename = self.filename_tpl.format(self)
+        if self.environment.machines[self.for_machine].is_os2():
+            # OS/2 does not allow a longer DLL name than 8 chars
+            name = os.path.splitext(self.filename)[0]
+            if len(name) > 8:
+                name = name[:8]
+                if self.soversion:
+                    name = name[:-len(self.soversion)] + self.soversion
+            self.filename = '{}.{}'.format(name, self.suffix)
         if import_filename_tpl:
             self.import_filename = import_filename_tpl.format(self)
         # There may have been more outputs added by the time we get here, so