vulkan: Add a common entrypoint table generator

This is based on the one in ANV but it's a bit different because it uses
vk_entrypoint_table instead of vk_dispatch_table.  This is because,
without knowing what extensions are implemented by a driver, we have to
generate a table with everything and sort it all out later.  We use the
same trick as ANV with weak function declarations to provide NULL values
for any entrypoints NOT implemented by the driver.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8676>

src/vulkan/util/vk_dispatch_table_gen.py

@@ -806,21 +806,10 @@ def get_entrypoints_defines(doc):
 
     return entrypoints_to_defines
 
-
-def main():
-    parser = argparse.ArgumentParser()
-    parser.add_argument('--out-c', help='Output C file.')
-    parser.add_argument('--out-h', help='Output H file.')
-    parser.add_argument('--xml',
-                        help='Vulkan API XML file.',
-                        required=True,
-                        action='append',
-                        dest='xml_files')
-    args = parser.parse_args()
-
+def get_entrypoints_from_xml(xml_files):
     entrypoints = []
 
-    for filename in args.xml_files:
+    for filename in xml_files:
         doc = et.parse(filename)
         entrypoints += get_entrypoints(doc, get_entrypoints_defines(doc))
 
@@ -836,6 +825,21 @@ def main():
         EntrypointParam('VkImage', 'pImage', 'VkImage* pImage')
     ]))
 
+    return entrypoints
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--out-c', help='Output C file.')
+    parser.add_argument('--out-h', help='Output H file.')
+    parser.add_argument('--xml',
+                        help='Vulkan API XML file.',
+                        required=True,
+                        action='append',
+                        dest='xml_files')
+    args = parser.parse_args()
+
+    entrypoints = get_entrypoints_from_xml(args.xml_files)
+
     device_entrypoints = []
     physical_device_entrypoints = []
     instance_entrypoints = []