extract_all_objects(): Recursively extract objects

Fixes #3401

3 files changed, 16 insertions, 10 deletions

diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index 8ecf393..2cca5e5 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -241,8 +241,11 @@ class Backend:
                                os.path.join('dummyprefixdir', fromdir))
 
     def flatten_object_list(self, target, proj_dir_to_build_root=''):
+        return self._flatten_object_list(target, target.get_objects(), proj_dir_to_build_root)
+
+    def _flatten_object_list(self, target, objects, proj_dir_to_build_root):
         obj_list = []
-        for obj in target.get_objects():
+        for obj in objects:
             if isinstance(obj, str):
                 o = os.path.join(proj_dir_to_build_root,
                                  self.build_to_src, target.get_subdir(), obj)
@@ -250,6 +253,7 @@ class Backend:
             elif isinstance(obj, mesonlib.File):
                 obj_list.append(obj.rel_to_builddir(self.build_to_src))
             elif isinstance(obj, build.ExtractedObjects):
+                obj_list += self._flatten_object_list(obj.target, obj.objlist, proj_dir_to_build_root)
                 obj_list += self.determine_ext_objs(obj, proj_dir_to_build_root)
             else:
                 raise MesonException('Unknown data type in object list.')
@@ -408,6 +412,10 @@ class Backend:
         # Filter out headers and all non-source files
         sources = [s for s in sources if self.environment.is_source(s) and not self.environment.is_header(s)]
 
+        # extobj could contain only objects and no sources
+        if not sources:
+            return result
+
         targetdir = self.get_target_private_dir(extobj.target)
 
         # With unity builds, there's just one object that contains all the
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index 083cd71..538254c 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -213,10 +213,11 @@ class ExtractedObjects:
     '''
     Holds a list of sources for which the objects must be extracted
     '''
-    def __init__(self, target, srclist, genlist):
+    def __init__(self, target, srclist=[], genlist=[], objlist=[]):
         self.target = target
         self.srclist = srclist
         self.genlist = genlist
+        self.objlist = objlist
         if self.target.is_unity:
             self.check_unity_compatible()
 
@@ -644,13 +645,10 @@ class BuildTarget(Target):
             if src not in self.sources:
                 raise MesonException('Tried to extract unknown source %s.' % src)
             obj_src.append(src)
-        return ExtractedObjects(self, obj_src, [])
+        return ExtractedObjects(self, obj_src)
 
     def extract_all_objects(self):
-        # FIXME: We should add support for transitive extract_objects()
-        if self.objects:
-            raise MesonException('Cannot extract objects from a target that itself has extracted objects')
-        return ExtractedObjects(self, self.sources, self.generated)
+        return ExtractedObjects(self, self.sources, self.generated, self.objects)
 
     def get_all_link_deps(self):
         return self.get_transitive_link_deps()
diff --git a/test cases/common/88 extract all/meson.build b/test cases/common/88 extract all/meson.build
index 91a8d5f..a56a3ce 100644
--- a/test cases/common/88 extract all/meson.build
+++ b/test cases/common/88 extract all/meson.build
@@ -2,8 +2,8 @@ project('extract all', 'c')
 
 a = static_library('a', 'one.c', 'two.c')
 b = static_library('b', 'three.c', 'four.c')
-c = static_library('c', 
-  objects : [a.extract_all_objects(), b.extract_all_objects()])
+c = static_library('c', objects : [a.extract_all_objects(), b.extract_all_objects()])
+d = static_library('d', objects : [c.extract_all_objects()])
 
-e = executable('proggie', 'prog.c', link_with : c)
+e = executable('proggie', 'prog.c', link_with : d)
 test('extall', e)