vk_dispatch_table_gen.py

# coding=utf-8
COPYRIGHT = """\
/*
 * Copyright 2020 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
"""

import argparse
import math
import os
import xml.etree.ElementTree as et

from collections import OrderedDict, namedtuple
from mako.template import Template

# Mesa-local imports must be declared in meson variable
# '{file_without_suffix}_depend_files'.
from vk_extensions import *

# We generate a static hash table for entry point lookup
# (vkGetProcAddress). We use a linear congruential generator for our hash
# function and a power-of-two size table. The prime numbers are determined
# experimentally.

TEMPLATE_H = Template(COPYRIGHT + """\
/* This file generated from ${filename}, don't edit directly. */

#ifndef VK_DISPATCH_TABLE_H
#define VK_DISPATCH_TABLE_H

#include "vulkan/vulkan.h"
#include "vulkan/vk_android_native_buffer.h"

#include "vk_extensions.h"

/* Windows api conflict */
#ifdef _WIN32
#include <windows.h>
#ifdef CreateSemaphore
#undef CreateSemaphore
#endif
#ifdef CreateEvent
#undef CreateEvent
#endif
#endif

#ifdef __cplusplus
extern "C" {
#endif

<%def name="dispatch_table(entrypoints)">
% for e in entrypoints:
  % if e.alias:
    <% continue %>
  % endif
  % if e.guard is not None:
#ifdef ${e.guard}
  % endif
  % if e.aliases:
    union {
        PFN_vk${e.name} ${e.name};
      % for a in e.aliases:
        PFN_vk${a.name} ${a.name};
      % endfor
    };
  % else:
    PFN_vk${e.name} ${e.name};
  % endif
  % if e.guard is not None:
#else
    % if e.aliases:
    union {
        PFN_vkVoidFunction ${e.name};
      % for a in e.aliases:
        PFN_vkVoidFunction ${a.name};
      % endfor
    };
    % else:
    PFN_vkVoidFunction ${e.name};
    % endif
#endif
  % endif
% endfor
</%def>

<%def name="entrypoint_table(type, entrypoints)">
struct vk_${type}_entrypoint_table {
% for e in entrypoints:
  % if e.guard is not None:
#ifdef ${e.guard}
  % endif
    PFN_vk${e.name} ${e.name};
  % if e.guard is not None:
#else
    PFN_vkVoidFunction ${e.name};
# endif
  % endif
% endfor
};
</%def>

struct vk_instance_dispatch_table {
  ${dispatch_table(instance_entrypoints)}
};

struct vk_physical_device_dispatch_table {
  ${dispatch_table(physical_device_entrypoints)}
};

struct vk_device_dispatch_table {
  ${dispatch_table(device_entrypoints)}
};

struct vk_dispatch_table {
    union {
        struct {
            struct vk_instance_dispatch_table instance;
            struct vk_physical_device_dispatch_table physical_device;
            struct vk_device_dispatch_table device;
        };

        struct {
            ${dispatch_table(instance_entrypoints)}
            ${dispatch_table(physical_device_entrypoints)}
            ${dispatch_table(device_entrypoints)}
        };
    };
};

${entrypoint_table('instance', instance_entrypoints)}
${entrypoint_table('physical_device', physical_device_entrypoints)}
${entrypoint_table('device', device_entrypoints)}

void
vk_instance_dispatch_table_load(struct vk_instance_dispatch_table *table,
                                PFN_vkGetInstanceProcAddr gpa,
                                VkInstance instance);
void
vk_physical_device_dispatch_table_load(struct vk_physical_device_dispatch_table *table,
                                       PFN_vkGetInstanceProcAddr gpa,
                                       VkInstance instance);
void
vk_device_dispatch_table_load(struct vk_device_dispatch_table *table,
                              PFN_vkGetDeviceProcAddr gpa,
                              VkDevice device);

void vk_instance_dispatch_table_from_entrypoints(
    struct vk_instance_dispatch_table *dispatch_table,
    const struct vk_instance_entrypoint_table *entrypoint_table,
    bool overwrite);

void vk_physical_device_dispatch_table_from_entrypoints(
    struct vk_physical_device_dispatch_table *dispatch_table,
    const struct vk_physical_device_entrypoint_table *entrypoint_table,
    bool overwrite);

void vk_device_dispatch_table_from_entrypoints(
    struct vk_device_dispatch_table *dispatch_table,
    const struct vk_device_entrypoint_table *entrypoint_table,
    bool overwrite);

PFN_vkVoidFunction
vk_instance_dispatch_table_get(const struct vk_instance_dispatch_table *table,
                               const char *name);

PFN_vkVoidFunction
vk_physical_device_dispatch_table_get(const struct vk_physical_device_dispatch_table *table,
                                      const char *name);

PFN_vkVoidFunction
vk_device_dispatch_table_get(const struct vk_device_dispatch_table *table,
                             const char *name);

PFN_vkVoidFunction
vk_instance_dispatch_table_get_if_supported(
    const struct vk_instance_dispatch_table *table,
    const char *name,
    uint32_t core_version,
    const struct vk_instance_extension_table *instance_exts);

PFN_vkVoidFunction
vk_physical_device_dispatch_table_get_if_supported(
    const struct vk_physical_device_dispatch_table *table,
    const char *name,
    uint32_t core_version,
    const struct vk_instance_extension_table *instance_exts);

PFN_vkVoidFunction
vk_device_dispatch_table_get_if_supported(
    const struct vk_device_dispatch_table *table,
    const char *name,
    uint32_t core_version,
    const struct vk_instance_extension_table *instance_exts,
    const struct vk_device_extension_table *device_exts);

extern struct vk_physical_device_dispatch_table vk_physical_device_trampolines;
extern struct vk_device_dispatch_table vk_device_trampolines;

#ifdef __cplusplus
}
#endif

#endif /* VK_DISPATCH_TABLE_H */
""", output_encoding='utf-8')

TEMPLATE_C = Template(COPYRIGHT + """\
/* This file generated from ${filename}, don't edit directly. */

#include "vk_device.h"
#include "vk_dispatch_table.h"
#include "vk_instance.h"
#include "vk_object.h"
#include "vk_physical_device.h"

#include "util/macros.h"
#include "string.h"

<%def name="load_dispatch_table(type, VkType, ProcAddr, entrypoints)">
void
vk_${type}_dispatch_table_load(struct vk_${type}_dispatch_table *table,
                               PFN_vk${ProcAddr} gpa,
                               ${VkType} obj)
{
% if type != 'physical_device':
    table->${ProcAddr} = gpa;
% endif
% for e in entrypoints:
  % if e.alias or e.name == '${ProcAddr}':
    <% continue %>
  % endif
  % if e.guard is not None:
#ifdef ${e.guard}
  % endif
    table->${e.name} = (PFN_vk${e.name}) gpa(obj, "vk${e.name}");
  % for a in e.aliases:
    if (table->${e.name} == NULL) {
        table->${e.name} = (PFN_vk${e.name}) gpa(obj, "vk${a.name}");
    }
  % endfor
  % if e.guard is not None:
#endif
  % endif
% endfor
}
</%def>

${load_dispatch_table('instance', 'VkInstance', 'GetInstanceProcAddr',
                      instance_entrypoints)}

${load_dispatch_table('physical_device', 'VkInstance', 'GetInstanceProcAddr',
                      physical_device_entrypoints)}

${load_dispatch_table('device', 'VkDevice', 'GetDeviceProcAddr',
                      device_entrypoints)}


struct string_map_entry {
   uint32_t name;
   uint32_t hash;
   uint32_t num;
};

/* We use a big string constant to avoid lots of reloctions from the entry
 * point table to lots of little strings. The entries in the entry point table
 * store the index into this big string.
 */

<%def name="strmap(strmap, prefix)">
static const char ${prefix}_strings[] =
% for s in strmap.sorted_strings:
    "${s.string}\\0"
% endfor
;

static const struct string_map_entry ${prefix}_string_map_entries[] = {
% for s in strmap.sorted_strings:
    { ${s.offset}, ${'{:0=#8x}'.format(s.hash)}, ${s.num} }, /* ${s.string} */
% endfor
};

/* Hash table stats:
 * size ${len(strmap.sorted_strings)} entries
 * collisions entries:
% for i in range(10):
 *     ${i}${'+' if i == 9 else ' '}     ${strmap.collisions[i]}
% endfor
 */

#define none 0xffff
static const uint16_t ${prefix}_string_map[${strmap.hash_size}] = {
% for e in strmap.mapping:
    ${ '{:0=#6x}'.format(e) if e >= 0 else 'none' },
% endfor
};

static int
${prefix}_string_map_lookup(const char *str)
{
    static const uint32_t prime_factor = ${strmap.prime_factor};
    static const uint32_t prime_step = ${strmap.prime_step};
    const struct string_map_entry *e;
    uint32_t hash, h;
    uint16_t i;
    const char *p;

    hash = 0;
    for (p = str; *p; p++)
        hash = hash * prime_factor + *p;

    h = hash;
    while (1) {
        i = ${prefix}_string_map[h & ${strmap.hash_mask}];
        if (i == none)
           return -1;
        e = &${prefix}_string_map_entries[i];
        if (e->hash == hash && strcmp(str, ${prefix}_strings + e->name) == 0)
            return e->num;
        h += prime_step;
    }

    return -1;
}
</%def>

${strmap(instance_strmap, 'instance')}
${strmap(physical_device_strmap, 'physical_device')}
${strmap(device_strmap, 'device')}

<% assert len(instance_entrypoints) < 2**8 %>
static const uint8_t instance_compaction_table[] = {
% for e in instance_entrypoints:
    ${e.disp_table_index},
% endfor
};

<% assert len(physical_device_entrypoints) < 2**8 %>
static const uint8_t physical_device_compaction_table[] = {
% for e in physical_device_entrypoints:
    ${e.disp_table_index},
% endfor
};

<% assert len(device_entrypoints) < 2**16 %>
static const uint16_t device_compaction_table[] = {
% for e in device_entrypoints:
    ${e.disp_table_index},
% endfor
};

static bool
vk_instance_entrypoint_is_enabled(int index, uint32_t core_version,
                                  const struct vk_instance_extension_table *instance)
{
   switch (index) {
% for e in instance_entrypoints:
   case ${e.entry_table_index}:
      /* ${e.name} */
   % if e.core_version:
      return ${e.core_version.c_vk_version()} <= core_version;
   % elif e.extensions:
     % for ext in e.extensions:
        % if ext.type == 'instance':
      if (instance->${ext.name[3:]}) return true;
        % else:
      /* All device extensions are considered enabled at the instance level */
      return true;
        % endif
     % endfor
      return false;
   % else:
      return true;
   % endif
% endfor
   default:
      return false;
   }
}

/** Return true if the core version or extension in which the given entrypoint
 * is defined is enabled.
 *
 * If device is NULL, all device extensions are considered enabled.
 */
static bool
vk_physical_device_entrypoint_is_enabled(int index, uint32_t core_version,
                                         const struct vk_instance_extension_table *instance)
{
   switch (index) {
% for e in physical_device_entrypoints:
   case ${e.entry_table_index}:
      /* ${e.name} */
   % if e.core_version:
      return ${e.core_version.c_vk_version()} <= core_version;
   % elif e.extensions:
     % for ext in e.extensions:
        % if ext.type == 'instance':
      if (instance->${ext.name[3:]}) return true;
        % else:
      /* All device extensions are considered enabled at the instance level */
      return true;
        % endif
     % endfor
      return false;
   % else:
      return true;
   % endif
% endfor
   default:
      return false;
   }
}

/** Return true if the core version or extension in which the given entrypoint
 * is defined is enabled.
 *
 * If device is NULL, all device extensions are considered enabled.
 */
static bool
vk_device_entrypoint_is_enabled(int index, uint32_t core_version,
                                const struct vk_instance_extension_table *instance,
                                const struct vk_device_extension_table *device)
{
   switch (index) {
% for e in device_entrypoints:
   case ${e.entry_table_index}:
      /* ${e.name} */
   % if e.core_version:
      return ${e.core_version.c_vk_version()} <= core_version;
   % elif e.extensions:
     % for ext in e.extensions:
        % if ext.type == 'instance':
      if (instance->${ext.name[3:]}) return true;
        % else:
      if (!device || device->${ext.name[3:]}) return true;
        % endif
     % endfor
      return false;
   % else:
      return true;
   % endif
% endfor
   default:
      return false;
   }
}

<%def name="dispatch_table_from_entrypoints(type)">
void vk_${type}_dispatch_table_from_entrypoints(
    struct vk_${type}_dispatch_table *dispatch_table,
    const struct vk_${type}_entrypoint_table *entrypoint_table,
    bool overwrite)
{
    PFN_vkVoidFunction *disp = (PFN_vkVoidFunction *)dispatch_table;
    PFN_vkVoidFunction *entry = (PFN_vkVoidFunction *)entrypoint_table;

    if (overwrite) {
        memset(dispatch_table, 0, sizeof(*dispatch_table));
        for (unsigned i = 0; i < ARRAY_SIZE(${type}_compaction_table); i++) {
#ifdef _MSC_VER
            const uintptr_t zero = 0;
            if (entry[i] == NULL || memcmp(entry[i], &zero, sizeof(zero)) == 0)
#else
            if (entry[i] == NULL)
#endif
                continue;
            unsigned disp_index = ${type}_compaction_table[i];
            assert(disp[disp_index] == NULL);
            disp[disp_index] = entry[i];
        }
    } else {
        for (unsigned i = 0; i < ARRAY_SIZE(${type}_compaction_table); i++) {
            unsigned disp_index = ${type}_compaction_table[i];
            if (disp[disp_index] == NULL)
                disp[disp_index] = entry[i];
        }
    }
}
</%def>

${dispatch_table_from_entrypoints('instance')}
${dispatch_table_from_entrypoints('physical_device')}
${dispatch_table_from_entrypoints('device')}

<%def name="lookup_funcs(type)">
static PFN_vkVoidFunction
vk_${type}_dispatch_table_get_for_entry_index(
    const struct vk_${type}_dispatch_table *table, int entry_index)
{
    assert(entry_index < ARRAY_SIZE(${type}_compaction_table));
    int disp_index = ${type}_compaction_table[entry_index];
    return ((PFN_vkVoidFunction *)table)[disp_index];
}

PFN_vkVoidFunction
vk_${type}_dispatch_table_get(
    const struct vk_${type}_dispatch_table *table, const char *name)
{
    int entry_index = ${type}_string_map_lookup(name);
    if (entry_index < 0)
        return NULL;

    return vk_${type}_dispatch_table_get_for_entry_index(table, entry_index);
}
</%def>

${lookup_funcs('instance')}
${lookup_funcs('physical_device')}
${lookup_funcs('device')}

PFN_vkVoidFunction
vk_instance_dispatch_table_get_if_supported(
    const struct vk_instance_dispatch_table *table,
    const char *name,
    uint32_t core_version,
    const struct vk_instance_extension_table *instance_exts)
{
    int entry_index = instance_string_map_lookup(name);
    if (entry_index < 0)
        return NULL;

    if (!vk_instance_entrypoint_is_enabled(entry_index, core_version,
                                           instance_exts))
        return NULL;

    return vk_instance_dispatch_table_get_for_entry_index(table, entry_index);
}

PFN_vkVoidFunction
vk_physical_device_dispatch_table_get_if_supported(
    const struct vk_physical_device_dispatch_table *table,
    const char *name,
    uint32_t core_version,
    const struct vk_instance_extension_table *instance_exts)
{
    int entry_index = physical_device_string_map_lookup(name);
    if (entry_index < 0)
        return NULL;

    if (!vk_physical_device_entrypoint_is_enabled(entry_index, core_version,
                                                  instance_exts))
        return NULL;

    return vk_physical_device_dispatch_table_get_for_entry_index(table, entry_index);
}

PFN_vkVoidFunction
vk_device_dispatch_table_get_if_supported(
    const struct vk_device_dispatch_table *table,
    const char *name,
    uint32_t core_version,
    const struct vk_instance_extension_table *instance_exts,
    const struct vk_device_extension_table *device_exts)
{
    int entry_index = device_string_map_lookup(name);
    if (entry_index < 0)
        return NULL;

    if (!vk_device_entrypoint_is_enabled(entry_index, core_version,
                                         instance_exts, device_exts))
        return NULL;

    return vk_device_dispatch_table_get_for_entry_index(table, entry_index);
}

% for e in physical_device_entrypoints:
  % if e.alias:
    <% continue %>
  % endif
  % if e.guard is not None:
#ifdef ${e.guard}
  % endif
static VKAPI_ATTR ${e.return_type} VKAPI_CALL
${e.prefixed_name('vk_tramp')}(${e.decl_params()})
{
    <% assert e.params[0].type == 'VkPhysicalDevice' %>
    VK_FROM_HANDLE(vk_physical_device, vk_physical_device, ${e.params[0].name});
  % if e.return_type == 'void':
    vk_physical_device->dispatch_table.${e.name}(${e.call_params()});
  % else:
    return vk_physical_device->dispatch_table.${e.name}(${e.call_params()});
  % endif
}
  % if e.guard is not None:
#endif
  % endif
% endfor

struct vk_physical_device_dispatch_table vk_physical_device_trampolines = {
% for e in physical_device_entrypoints:
  % if e.alias:
    <% continue %>
  % endif
  % if e.guard is not None:
#ifdef ${e.guard}
  % endif
    .${e.name} = ${e.prefixed_name('vk_tramp')},
  % if e.guard is not None:
#endif
  % endif
% endfor
};

% for e in device_entrypoints:
  % if e.alias:
    <% continue %>
  % endif
  % if e.guard is not None:
#ifdef ${e.guard}
  % endif
static VKAPI_ATTR ${e.return_type} VKAPI_CALL
${e.prefixed_name('vk_tramp')}(${e.decl_params()})
{
  % if e.params[0].type == 'VkDevice':
    VK_FROM_HANDLE(vk_device, vk_device, ${e.params[0].name});
    % if e.return_type == 'void':
    vk_device->dispatch_table.${e.name}(${e.call_params()});
    % else:
    return vk_device->dispatch_table.${e.name}(${e.call_params()});
    % endif
  % elif e.params[0].type in ('VkCommandBuffer', 'VkQueue'):
    struct vk_object_base *vk_object = (struct vk_object_base *)${e.params[0].name};
    % if e.return_type == 'void':
    vk_object->device->dispatch_table.${e.name}(${e.call_params()});
    % else:
    return vk_object->device->dispatch_table.${e.name}(${e.call_params()});
    % endif
  % else:
    assert(!"Unhandled device child trampoline case: ${e.params[0].type}");
  % endif
}
  % if e.guard is not None:
#endif
  % endif
% endfor

struct vk_device_dispatch_table vk_device_trampolines = {
% for e in device_entrypoints:
  % if e.alias:
    <% continue %>
  % endif
  % if e.guard is not None:
#ifdef ${e.guard}
  % endif
    .${e.name} = ${e.prefixed_name('vk_tramp')},
  % if e.guard is not None:
#endif
  % endif
% endfor
};
""", output_encoding='utf-8')

U32_MASK = 2**32 - 1

PRIME_FACTOR = 5024183
PRIME_STEP = 19

class StringIntMapEntry(object):
    def __init__(self, string, num):
        self.string = string
        self.num = num

        # Calculate the same hash value that we will calculate in C.
        h = 0
        for c in string:
            h = ((h * PRIME_FACTOR) + ord(c)) & U32_MASK
        self.hash = h

        self.offset = None

def round_to_pow2(x):
    return 2**int(math.ceil(math.log(x, 2)))

class StringIntMap(object):
    def __init__(self):
        self.baked = False
        self.strings = dict()

    def add_string(self, string, num):
        assert not self.baked
        assert string not in self.strings
        assert 0 <= num < 2**31
        self.strings[string] = StringIntMapEntry(string, num)

    def bake(self):
        self.sorted_strings = \
            sorted(self.strings.values(), key=lambda x: x.string)
        offset = 0
        for entry in self.sorted_strings:
            entry.offset = offset
            offset += len(entry.string) + 1

        # Save off some values that we'll need in C
        self.hash_size = round_to_pow2(len(self.strings) * 1.25)
        self.hash_mask = self.hash_size - 1
        self.prime_factor = PRIME_FACTOR
        self.prime_step = PRIME_STEP

        self.mapping = [-1] * self.hash_size
        self.collisions = [0] * 10
        for idx, s in enumerate(self.sorted_strings):
            level = 0
            h = s.hash
            while self.mapping[h & self.hash_mask] >= 0:
                h = h + PRIME_STEP
                level = level + 1
            self.collisions[min(level, 9)] += 1
            self.mapping[h & self.hash_mask] = idx

EntrypointParam = namedtuple('EntrypointParam', 'type name decl')

class EntrypointBase(object):
    def __init__(self, name):
        assert name.startswith('vk')
        self.name = name[2:]
        self.alias = None
        self.guard = None
        self.entry_table_index = None
        # Extensions which require this entrypoint
        self.core_version = None
        self.extensions = []

    def prefixed_name(self, prefix):
        return prefix + '_' + self.name

class Entrypoint(EntrypointBase):
    def __init__(self, name, return_type, params, guard=None):
        super(Entrypoint, self).__init__(name)
        self.return_type = return_type
        self.params = params
        self.guard = guard
        self.aliases = []
        self.disp_table_index = None

    def is_physical_device_entrypoint(self):
        return self.params[0].type in ('VkPhysicalDevice', )

    def is_device_entrypoint(self):
        return self.params[0].type in ('VkDevice', 'VkCommandBuffer', 'VkQueue')

    def decl_params(self):
        return ', '.join(p.decl for p in self.params)

    def call_params(self):
        return ', '.join(p.name for p in self.params)

class EntrypointAlias(EntrypointBase):
    def __init__(self, name, entrypoint):
        super(EntrypointAlias, self).__init__(name)
        self.alias = entrypoint
        entrypoint.aliases.append(self)

    def is_physical_device_entrypoint(self):
        return self.alias.is_physical_device_entrypoint()

    def is_device_entrypoint(self):
        return self.alias.is_device_entrypoint()

    def prefixed_name(self, prefix):
        return self.alias.prefixed_name(prefix)

    @property
    def params(self):
        return self.alias.params

    @property
    def return_type(self):
        return self.alias.return_type

    @property
    def disp_table_index(self):
        return self.alias.disp_table_index

    def decl_params(self):
        return self.alias.decl_params()

    def call_params(self):
        return self.alias.call_params()

def get_entrypoints(doc, entrypoints_to_defines):
    """Extract the entry points from the registry."""
    entrypoints = OrderedDict()

    for command in doc.findall('./commands/command'):
        if 'alias' in command.attrib:
            alias = command.attrib['name']
            target = command.attrib['alias']
            entrypoints[alias] = EntrypointAlias(alias, entrypoints[target])
        else:
            name = command.find('./proto/name').text
            ret_type = command.find('./proto/type').text
            params = [EntrypointParam(
                type=p.find('./type').text,
                name=p.find('./name').text,
                decl=''.join(p.itertext())
            ) for p in command.findall('./param')]
            guard = entrypoints_to_defines.get(name)
            # They really need to be unique
            assert name not in entrypoints
            entrypoints[name] = Entrypoint(name, ret_type, params, guard)

    for feature in doc.findall('./feature'):
        assert feature.attrib['api'] == 'vulkan'
        version = VkVersion(feature.attrib['number'])
        for command in feature.findall('./require/command'):
            e = entrypoints[command.attrib['name']]
            assert e.core_version is None
            e.core_version = version

    for extension in doc.findall('.extensions/extension'):
        if extension.attrib['supported'] != 'vulkan':
            continue

        ext_name = extension.attrib['name']

        ext = Extension(ext_name, 1, True)
        ext.type = extension.attrib['type']

        for command in extension.findall('./require/command'):
            e = entrypoints[command.attrib['name']]
            assert e.core_version is None
            e.extensions.append(ext)

    return entrypoints.values()


def get_entrypoints_defines(doc):
    """Maps entry points to extension defines."""
    entrypoints_to_defines = {}

    platform_define = {}
    for platform in doc.findall('./platforms/platform'):
        name = platform.attrib['name']
        define = platform.attrib['protect']
        platform_define[name] = define

    for extension in doc.findall('./extensions/extension[@platform]'):
        platform = extension.attrib['platform']
        define = platform_define[platform]

        for entrypoint in extension.findall('./require/command'):
            fullname = entrypoint.attrib['name']
            entrypoints_to_defines[fullname] = define

    return entrypoints_to_defines

def get_entrypoints_from_xml(xml_files):
    entrypoints = []

    for filename in xml_files:
        doc = et.parse(filename)
        entrypoints += get_entrypoints(doc, get_entrypoints_defines(doc))

    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 = []
    for e in entrypoints:
        if e.is_device_entrypoint():
            device_entrypoints.append(e)
        elif e.is_physical_device_entrypoint():
            physical_device_entrypoints.append(e)
        else:
            instance_entrypoints.append(e)

    for i, e in enumerate(e for e in device_entrypoints if not e.alias):
        e.disp_table_index = i

    device_strmap = StringIntMap()
    for i, e in enumerate(device_entrypoints):
        e.entry_table_index = i
        device_strmap.add_string("vk" + e.name, e.entry_table_index)
    device_strmap.bake()

    for i, e in enumerate(e for e in physical_device_entrypoints if not e.alias):
        e.disp_table_index = i

    physical_device_strmap = StringIntMap()
    for i, e in enumerate(physical_device_entrypoints):
        e.entry_table_index = i
        physical_device_strmap.add_string("vk" + e.name, e.entry_table_index)
    physical_device_strmap.bake()

    for i, e in enumerate(e for e in instance_entrypoints if not e.alias):
        e.disp_table_index = i

    instance_strmap = StringIntMap()
    for i, e in enumerate(instance_entrypoints):
        e.entry_table_index = i
        instance_strmap.add_string("vk" + e.name, e.entry_table_index)
    instance_strmap.bake()

    # For outputting entrypoints.h we generate a anv_EntryPoint() prototype
    # per entry point.
    try:
        if args.out_h:
            with open(args.out_h, 'wb') as f:
                f.write(TEMPLATE_H.render(instance_entrypoints=instance_entrypoints,
                                          physical_device_entrypoints=physical_device_entrypoints,
                                          device_entrypoints=device_entrypoints,
                                          filename=os.path.basename(__file__)))
        if args.out_c:
            with open(args.out_c, 'wb') as f:
                f.write(TEMPLATE_C.render(instance_entrypoints=instance_entrypoints,
                                          physical_device_entrypoints=physical_device_entrypoints,
                                          device_entrypoints=device_entrypoints,
                                          instance_strmap=instance_strmap,
                                          physical_device_strmap=physical_device_strmap,
                                          device_strmap=device_strmap,
                                          filename=os.path.basename(__file__)))
    except Exception:
        # In the event there's an error, this imports some helpers from mako
        # to print a useful stack trace and prints it, then exits with
        # status 1, if python is run with debug; otherwise it just raises
        # the exception
        if __debug__:
            import sys
            from mako import exceptions
            sys.stderr.write(exceptions.text_error_template().render() + '\n')
            sys.exit(1)
        raise


if __name__ == '__main__':
    main()