[Mesa-dev] [PATCH] vulkan: enums: fix generation with enum aliases

[Lionel Landwerlin]

It seems new extensions will start to use aliases in enums, meaning
multiple enums with the same value. This forces us to track the values
of the enums to generate correct C code.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Cc: Dylan Baker <dylan at pnwbakers.com>
---
 src/vulkan/util/gen_enum_to_str.py | 49 ++++++++++++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 10 deletions(-)

diff --git a/src/vulkan/util/gen_enum_to_str.py b/src/vulkan/util/gen_enum_to_str.py
index fb31addf94..1ffe4e362b 100644
--- a/src/vulkan/util/gen_enum_to_str.py
+++ b/src/vulkan/util/gen_enum_to_str.py
@@ -24,6 +24,7 @@
 from __future__ import print_function
 import argparse
 import os
+import re
 import textwrap
 import xml.etree.cElementTree as et
 
@@ -67,9 +68,9 @@ C_TEMPLATE = Template(textwrap.dedent(u"""\
         vk_${enum.name[2:]}_to_str(${enum.name} input)
         {
             switch(input) {
-            % for v in enum.values:
-                case ${v}:
-                    return "${v}";
+            % for k, v in enum.values.iteritems():
+                case ${v[0]}:
+                    return "${' / '.join(v)}";
             % endfor
             default:
                 unreachable("Undefined enum value.");
@@ -116,10 +117,17 @@ class EnumFactory(object):
 class VkEnum(object):
     """Simple struct-like class representing a single Vulkan Enum."""
 
-    def __init__(self, name, values=None):
+    def __init__(self, name):
         self.name = name
-        self.values = values or []
+        self.values = {}
+        self.names = {}
 
+    def add_item(self, name, value):
+        if value in self.values:
+            self.values[value].append(name)
+        else:
+            self.values[value] = [name]
+        self.names[name] = value
 
 def xml_parser(filename):
     """Parse the XML file and return parsed data.
@@ -129,6 +137,24 @@ def xml_parser(filename):
     """
     efactory = EnumFactory(VkEnum)
 
+    number_regexp = re.compile('^-?[0-9]+$')
+
+    def compute_enum_value(enum, elem, parent):
+        if 'offset' in elem.attrib:
+            # Formula taken from the src/spec/generator.py
+            # https://github.com/khronosGroup/Vulkan-Docs
+            value = 1000000000 + (int(parent.attrib['number']) - 1) * 1000
+            value += int(elem.attrib['offset'])
+            if 'dir' in e.attrib:
+                value = -value
+        else:
+            number = elem.attrib['value']
+            if re.match(number_regexp, number):
+                value = int(number)
+            else:
+                value = enum.names[number]
+        return value
+
     with open(filename, 'rb') as f:
         context = iter(et.iterparse(f, events=('start', 'end')))
 
@@ -140,16 +166,19 @@ def xml_parser(filename):
         for event, elem in context:
             if event == 'end' and elem.tag == 'enums':
                 type_ = elem.attrib.get('type')
-                if type_ == 'enum':
-                    enum = efactory(elem.attrib['name'])
-                    enum.values.extend([e.attrib['name'] for e in elem
-                                        if e.tag == 'enum'])
+                if type_ != 'enum':
+                    continue
+                enum = efactory(elem.attrib['name'])
+                for e in elem:
+                    if e.tag != 'enum':
+                        continue
+                    enum.add_item(e.attrib['name'], compute_enum_value(enum, e, None))
             elif event == 'end' and elem.tag == 'extension':
                 if elem.attrib['supported'] != 'vulkan':
                     continue
                 for e in elem.findall('.//enum[@extends][@offset]'):
                     enum = efactory(e.attrib['extends'])
-                    enum.values.append(e.attrib['name'])
+                    enum.add_item(e.attrib['name'], compute_enum_value(enum, e, elem))
 
             root.clear()
 
-- 
2.11.0