vulkan/util: generate define for a selected few enums

One of the unfortunate effect of Vulkan starting to use 64bit bitmasks
is that they can no longer be defined using enums because C doesn't
guarantees that enum values will be 64bits.

Vulkan therefore started using those patterns :

  static const VkAccessFlags2KHR VK_ACCESS_2_INDIRECT_COMMAND_READ_BIT_KHR = 0x00000001;

This has the effect that we can not longer use those values in
switch/case statements.

This change introduces defines so that we can keep doing this. For now
only VkAccessFlags2KHR/VkPipelineStageFlags2KHR are allowed to be
redefined this way, this list could be changed later (or all bitmask
could be processed this way).

v2: Generate hexadecimal numbers (Jason)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9045>

src/vulkan/util/gen_enum_to_str.py

@@ -178,6 +178,19 @@ H_DEFINE_TEMPLATE = Template(textwrap.dedent(u"""\
     #define _${ext.name}_number (${ext.number})
     % endfor
 
+    % for enum in bitmasks:
+    /* Redefine bitmask values of ${enum.name} */
+      % if enum.guard:
+#ifdef ${enum.guard}
+      % endif
+      % for v in enum.values.keys():
+    #define ${enum.values[v]} (${hex(v)}ULL)
+      % endfor
+      % if enum.guard:
+#endif
+      % endif
+    % endfor
+
     #ifdef __cplusplus
     } /* extern "C" */
     #endif
@@ -262,6 +275,9 @@ class VkEnum(object):
         if 'value' in elem.attrib:
             self.add_value(elem.attrib['name'],
                            value=int(elem.attrib['value'], base=0))
+        elif 'bitpos' in elem.attrib:
+            self.add_value(elem.attrib['name'],
+                           value=(1 << int(elem.attrib['bitpos'], base=0)))
         elif 'alias' in elem.attrib:
             self.add_value(elem.attrib['name'], alias=elem.attrib['alias'])
         else:
@@ -301,8 +317,8 @@ class VkObjectType(object):
         self.enum_to_name = dict()
 
 
-def parse_xml(enum_factory, ext_factory, struct_factory, obj_type_factory,
-              filename):
+def parse_xml(enum_factory, ext_factory, struct_factory, bitmask_factory,
+              obj_type_factory, filename):
     """Parse the XML file. Accumulate results into the factories.
 
     This parser is a memory efficient iterative XML parser that returns a list
@@ -316,8 +332,19 @@ def parse_xml(enum_factory, ext_factory, struct_factory, obj_type_factory,
         for value in enum_type.findall('./enum'):
             enum.add_value_from_xml(value)
 
+    # For bitmask we only add the Enum selected for convenience.
+    for enum_type in xml.findall('./enums[@type="bitmask"]'):
+        enum = bitmask_factory.get(enum_type.attrib['name'])
+        if enum is not None:
+            for value in enum_type.findall('./enum'):
+                enum.add_value_from_xml(value)
+
     for value in xml.findall('./feature/require/enum[@extends]'):
-        enum = enum_factory.get(value.attrib['extends'])
+        extends = value.attrib['extends']
+        enum = enum_factory.get(extends)
+        if enum is not None:
+            enum.add_value_from_xml(value)
+        enum = bitmask_factory.get(extends)
         if enum is not None:
             enum.add_value_from_xml(value)
 
@@ -342,7 +369,11 @@ def parse_xml(enum_factory, ext_factory, struct_factory, obj_type_factory,
                                 define=define)
 
         for value in ext_elem.findall('./require/enum[@extends]'):
-            enum = enum_factory.get(value.attrib['extends'])
+            extends = value.attrib['extends']
+            enum = enum_factory.get(extends)
+            if enum is not None:
+                enum.add_value_from_xml(value, extension)
+            enum = bitmask_factory.get(extends)
             if enum is not None:
                 enum.add_value_from_xml(value, extension)
         for t in ext_elem.findall('./require/type'):
@@ -381,12 +412,19 @@ def main():
     ext_factory = NamedFactory(VkExtension)
     struct_factory = NamedFactory(VkChainStruct)
     obj_type_factory = NamedFactory(VkObjectType)
+
+    # Only treat this bitmask for now
+    bitmask_factory = NamedFactory(VkEnum)
+    bitmask_factory('VkAccessFlagBits2KHR')
+    bitmask_factory('VkPipelineStageFlagBits2KHR')
+
     for filename in args.xml_files:
-        parse_xml(enum_factory, ext_factory, struct_factory, obj_type_factory,
-                  filename)
+        parse_xml(enum_factory, ext_factory, struct_factory, bitmask_factory,
+                  obj_type_factory, filename)
     enums = sorted(enum_factory.registry.values(), key=lambda e: e.name)
     extensions = sorted(ext_factory.registry.values(), key=lambda e: e.name)
     structs = sorted(struct_factory.registry.values(), key=lambda e: e.name)
+    bitmasks = sorted(bitmask_factory.registry.values(), key=lambda e: e.name)
     object_types = sorted(obj_type_factory.registry.values(), key=lambda e: e.name)
 
     for template, file_ in [(C_TEMPLATE, os.path.join(args.outdir, 'vk_enum_to_str.c')),
@@ -398,6 +436,7 @@ def main():
                 enums=enums,
                 extensions=extensions,
                 structs=structs,
+                bitmasks=bitmasks,
                 object_types=object_types,
                 copyright=COPYRIGHT))