src/intel/vulkan/anv_entrypoints_gen.py

   1 # coding=utf-8
   2 #
   3 # Copyright © 2015, 2017 Intel Corporation
   4 #
   5 # Permission is hereby granted, free of charge, to any person obtaining a
   6 # copy of this software and associated documentation files (the "Software"),
   7 # to deal in the Software without restriction, including without limitation
   8 # the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9 # and/or sell copies of the Software, and to permit persons to whom the
  10 # Software is furnished to do so, subject to the following conditions:
  11 #
  12 # The above copyright notice and this permission notice (including the next
  13 # paragraph) shall be included in all copies or substantial portions of the
  14 # Software.
  15 #
  16 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19 # THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  22 # IN THE SOFTWARE.
  23 #
  24
  25 import argparse
  26 import math
  27 import os
  28 import xml.etree.cElementTree as et
  29
  30 from collections import OrderedDict, namedtuple
  31 from mako.template import Template
  32
  33 from anv_extensions import VkVersion, MAX_API_VERSION, EXTENSIONS
  34
  35 # We generate a static hash table for entry point lookup
  36 # (vkGetProcAddress). We use a linear congruential generator for our hash
  37 # function and a power-of-two size table. The prime numbers are determined
  38 # experimentally.
  39
  40 LAYERS = [
  41     'anv',
  42     'gen7',
  43     'gen75',
  44     'gen8',
  45     'gen9',
  46     'gen10',
  47     'gen11',
  48 ]
  49
  50 TEMPLATE_H = Template("""\
  51 /* This file generated from ${filename}, don't edit directly. */
  52
  53 struct anv_instance_dispatch_table {
  54    union {
  55       void *entrypoints[${len(instance_entrypoints)}];
  56       struct {
  57       % for e in instance_entrypoints:
  58         % if e.guard is not None:
  59 #ifdef ${e.guard}
  60           PFN_${e.name} ${e.name};
  61 #else
  62           void *${e.name};
  63 # endif
  64         % else:
  65           PFN_${e.name} ${e.name};
  66         % endif
  67       % endfor
  68       };
  69    };
  70 };
  71
  72 struct anv_device_dispatch_table {
  73    union {
  74       void *entrypoints[${len(device_entrypoints)}];
  75       struct {
  76       % for e in device_entrypoints:
  77         % if e.guard is not None:
  78 #ifdef ${e.guard}
  79           PFN_${e.name} ${e.name};
  80 #else
  81           void *${e.name};
  82 # endif
  83         % else:
  84           PFN_${e.name} ${e.name};
  85         % endif
  86       % endfor
  87       };
  88    };
  89 };
  90
  91 extern const struct anv_instance_dispatch_table anv_instance_dispatch_table;
  92 %for layer in LAYERS:
  93 extern const struct anv_device_dispatch_table ${layer}_device_dispatch_table;
  94 %endfor
  95 extern const struct anv_device_dispatch_table anv_tramp_device_dispatch_table;
  96
  97 % for e in instance_entrypoints:
  98   % if e.alias:
  99     <% continue %>
 100   % endif
 101   % if e.guard is not None:
 102 #ifdef ${e.guard}
 103   % endif
 104   ${e.return_type} ${e.prefixed_name('anv')}(${e.decl_params()});
 105   % if e.guard is not None:
 106 #endif // ${e.guard}
 107   % endif
 108 % endfor
 109
 110 % for e in device_entrypoints:
 111   % if e.alias:
 112     <% continue %>
 113   % endif
 114   % if e.guard is not None:
 115 #ifdef ${e.guard}
 116   % endif
 117   % for layer in LAYERS:
 118   ${e.return_type} ${e.prefixed_name(layer)}(${e.decl_params()});
 119   % endfor
 120   % if e.guard is not None:
 121 #endif // ${e.guard}
 122   % endif
 123 % endfor
 124 """, output_encoding='utf-8')
 125
 126 TEMPLATE_C = Template(u"""\
 127 /*
 128  * Copyright © 2015 Intel Corporation
 129  *
 130  * Permission is hereby granted, free of charge, to any person obtaining a
 131  * copy of this software and associated documentation files (the "Software"),
 132  * to deal in the Software without restriction, including without limitation
 133  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 134  * and/or sell copies of the Software, and to permit persons to whom the
 135  * Software is furnished to do so, subject to the following conditions:
 136  *
 137  * The above copyright notice and this permission notice (including the next
 138  * paragraph) shall be included in all copies or substantial portions of the
 139  * Software.
 140  *
 141  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 142  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 143  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 144  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 145  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 146  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 147  * IN THE SOFTWARE.
 148  */
 149
 150 /* This file generated from ${filename}, don't edit directly. */
 151
 152 #include "anv_private.h"
 153
 154 struct string_map_entry {
 155    uint32_t name;
 156    uint32_t hash;
 157    uint32_t num;
 158 };
 159
 160 /* We use a big string constant to avoid lots of reloctions from the entry
 161  * point table to lots of little strings. The entries in the entry point table
 162  * store the index into this big string.
 163  */
 164
 165 <%def name="strmap(strmap, prefix)">
 166 static const char ${prefix}_strings[] =
 167 % for s in strmap.sorted_strings:
 168     "${s.string}\\0"
 169 % endfor
 170 ;
 171
 172 static const struct string_map_entry ${prefix}_string_map_entries[] = {
 173 % for s in strmap.sorted_strings:
 174     { ${s.offset}, ${'{:0=#8x}'.format(s.hash)}, ${s.num} }, /* ${s.string} */
 175 % endfor
 176 };
 177
 178 /* Hash table stats:
 179  * size ${len(strmap.sorted_strings)} entries
 180  * collisions entries:
 181 % for i in range(10):
 182  *     ${i}${'+' if i == 9 else ' '}     ${strmap.collisions[i]}
 183 % endfor
 184  */
 185
 186 #define none 0xffff
 187 static const uint16_t ${prefix}_string_map[${strmap.hash_size}] = {
 188 % for e in strmap.mapping:
 189     ${ '{:0=#6x}'.format(e) if e >= 0 else 'none' },
 190 % endfor
 191 };
 192
 193 static int
 194 ${prefix}_string_map_lookup(const char *str)
 195 {
 196     static const uint32_t prime_factor = ${strmap.prime_factor};
 197     static const uint32_t prime_step = ${strmap.prime_step};
 198     const struct string_map_entry *e;
 199     uint32_t hash, h;
 200     uint16_t i;
 201     const char *p;
 202
 203     hash = 0;
 204     for (p = str; *p; p++)
 205         hash = hash * prime_factor + *p;
 206
 207     h = hash;
 208     while (1) {
 209         i = ${prefix}_string_map[h & ${strmap.hash_mask}];
 210         if (i == none)
 211            return -1;
 212         e = &${prefix}_string_map_entries[i];
 213         if (e->hash == hash && strcmp(str, ${prefix}_strings + e->name) == 0)
 214             return e->num;
 215         h += prime_step;
 216     }
 217
 218     return -1;
 219 }
 220 </%def>
 221
 222 ${strmap(instance_strmap, 'instance')}
 223 ${strmap(device_strmap, 'device')}
 224
 225 /* Weak aliases for all potential implementations. These will resolve to
 226  * NULL if they're not defined, which lets the resolve_entrypoint() function
 227  * either pick the correct entry point.
 228  */
 229
 230 const struct anv_instance_dispatch_table anv_instance_dispatch_table = {
 231 % for e in instance_entrypoints:
 232   % if e.guard is not None:
 233 #ifdef ${e.guard}
 234   % endif
 235   .${e.name} = ${e.prefixed_name('anv')},
 236   % if e.guard is not None:
 237 #endif // ${e.guard}
 238   % endif
 239 % endfor
 240 };
 241
 242 % for layer in LAYERS:
 243   % for e in device_entrypoints:
 244     % if e.alias:
 245       <% continue %>
 246     % endif
 247     % if e.guard is not None:
 248 #ifdef ${e.guard}
 249     % endif
 250     ${e.return_type} ${e.prefixed_name(layer)}(${e.decl_params()}) __attribute__ ((weak));
 251     % if e.guard is not None:
 252 #endif // ${e.guard}
 253     % endif
 254   % endfor
 255
 256   const struct anv_device_dispatch_table ${layer}_device_dispatch_table = {
 257   % for e in device_entrypoints:
 258     % if e.guard is not None:
 259 #ifdef ${e.guard}
 260     % endif
 261     .${e.name} = ${e.prefixed_name(layer)},
 262     % if e.guard is not None:
 263 #endif // ${e.guard}
 264     % endif
 265   % endfor
 266   };
 267 % endfor
 268
 269
 270 /** Trampoline entrypoints for all device functions */
 271
 272 % for e in device_entrypoints:
 273   % if e.alias:
 274     <% continue %>
 275   % endif
 276   % if e.guard is not None:
 277 #ifdef ${e.guard}
 278   % endif
 279   static ${e.return_type}
 280   ${e.prefixed_name('anv_tramp')}(${e.decl_params()})
 281   {
 282     % if e.params[0].type == 'VkDevice':
 283       ANV_FROM_HANDLE(anv_device, anv_device, ${e.params[0].name});
 284       return anv_device->dispatch.${e.name}(${e.call_params()});
 285     % elif e.params[0].type == 'VkCommandBuffer':
 286       ANV_FROM_HANDLE(anv_cmd_buffer, anv_cmd_buffer, ${e.params[0].name});
 287       return anv_cmd_buffer->device->dispatch.${e.name}(${e.call_params()});
 288     % elif e.params[0].type == 'VkQueue':
 289       ANV_FROM_HANDLE(anv_queue, anv_queue, ${e.params[0].name});
 290       return anv_queue->device->dispatch.${e.name}(${e.call_params()});
 291     % else:
 292       assert(!"Unhandled device child trampoline case: ${e.params[0].type}");
 293     % endif
 294   }
 295   % if e.guard is not None:
 296 #endif // ${e.guard}
 297   % endif
 298 % endfor
 299
 300 const struct anv_device_dispatch_table anv_tramp_device_dispatch_table = {
 301 % for e in device_entrypoints:
 302   % if e.guard is not None:
 303 #ifdef ${e.guard}
 304   % endif
 305     .${e.name} = ${e.prefixed_name('anv_tramp')},
 306   % if e.guard is not None:
 307 #endif // ${e.guard}
 308   % endif
 309 % endfor
 310 };
 311
 312
 313 /** Return true if the core version or extension in which the given entrypoint
 314  * is defined is enabled.
 315  *
 316  * If device is NULL, all device extensions are considered enabled.
 317  */
 318 bool
 319 anv_instance_entrypoint_is_enabled(int index, uint32_t core_version,
 320                                    const struct anv_instance_extension_table *instance)
 321 {
 322    switch (index) {
 323 % for e in instance_entrypoints:
 324    case ${e.num}:
 325       /* ${e.name} */
 326    % if e.core_version:
 327       return ${e.core_version.c_vk_version()} <= core_version;
 328    % elif e.extensions:
 329      % for ext in e.extensions:
 330         % if ext.type == 'instance':
 331       if (instance->${ext.name[3:]}) return true;
 332         % else:
 333       /* All device extensions are considered enabled at the instance level */
 334       return true;
 335         % endif
 336      % endfor
 337       return false;
 338    % else:
 339       return true;
 340    % endif
 341 % endfor
 342    default:
 343       return false;
 344    }
 345 }
 346
 347 /** Return true if the core version or extension in which the given entrypoint
 348  * is defined is enabled.
 349  *
 350  * If device is NULL, all device extensions are considered enabled.
 351  */
 352 bool
 353 anv_device_entrypoint_is_enabled(int index, uint32_t core_version,
 354                                  const struct anv_instance_extension_table *instance,
 355                                  const struct anv_device_extension_table *device)
 356 {
 357    switch (index) {
 358 % for e in device_entrypoints:
 359    case ${e.num}:
 360       /* ${e.name} */
 361    % if e.core_version:
 362       return ${e.core_version.c_vk_version()} <= core_version;
 363    % elif e.extensions:
 364      % for ext in e.extensions:
 365         % if ext.type == 'instance':
 366            <% assert False %>
 367         % else:
 368       if (!device || device->${ext.name[3:]}) return true;
 369         % endif
 370      % endfor
 371       return false;
 372    % else:
 373       return true;
 374    % endif
 375 % endfor
 376    default:
 377       return false;
 378    }
 379 }
 380
 381 int
 382 anv_get_instance_entrypoint_index(const char *name)
 383 {
 384    return instance_string_map_lookup(name);
 385 }
 386
 387 int
 388 anv_get_device_entrypoint_index(const char *name)
 389 {
 390    return device_string_map_lookup(name);
 391 }
 392
 393 static void * __attribute__ ((noinline))
 394 anv_resolve_device_entrypoint(const struct gen_device_info *devinfo, uint32_t index)
 395 {
 396    const struct anv_device_dispatch_table *genX_table;
 397    switch (devinfo->gen) {
 398    case 11:
 399       genX_table = &gen11_device_dispatch_table;
 400       break;
 401    case 10:
 402       genX_table = &gen10_device_dispatch_table;
 403       break;
 404    case 9:
 405       genX_table = &gen9_device_dispatch_table;
 406       break;
 407    case 8:
 408       genX_table = &gen8_device_dispatch_table;
 409       break;
 410    case 7:
 411       if (devinfo->is_haswell)
 412          genX_table = &gen75_device_dispatch_table;
 413       else
 414          genX_table = &gen7_device_dispatch_table;
 415       break;
 416    default:
 417       unreachable("unsupported gen\\n");
 418    }
 419
 420    if (genX_table->entrypoints[index])
 421       return genX_table->entrypoints[index];
 422    else
 423       return anv_device_dispatch_table.entrypoints[index];
 424 }
 425
 426 void *
 427 anv_lookup_entrypoint(const struct gen_device_info *devinfo, const char *name)
 428 {
 429    int idx = anv_get_instance_entrypoint_index(name);
 430    if (idx >= 0)
 431       return anv_instance_dispatch_table.entrypoints[idx];
 432
 433    idx = anv_get_device_entrypoint_index(name);
 434    if (idx >= 0)
 435       return anv_resolve_device_entrypoint(devinfo, idx);
 436
 437    return NULL;
 438 }""", output_encoding='utf-8')
 439
 440 U32_MASK = 2**32 - 1
 441
 442 PRIME_FACTOR = 5024183
 443 PRIME_STEP = 19
 444
 445 class StringIntMapEntry(object):
 446     def __init__(self, string, num):
 447         self.string = string
 448         self.num = num
 449
 450         # Calculate the same hash value that we will calculate in C.
 451         h = 0
 452         for c in string:
 453             h = ((h * PRIME_FACTOR) + ord(c)) & U32_MASK
 454         self.hash = h
 455
 456         self.offset = None
 457
 458 def round_to_pow2(x):
 459     return 2**int(math.ceil(math.log(x, 2)))
 460
 461 class StringIntMap(object):
 462     def __init__(self):
 463         self.baked = False
 464         self.strings = dict()
 465
 466     def add_string(self, string, num):
 467         assert not self.baked
 468         assert string not in self.strings
 469         assert num >= 0 and num < 2**31
 470         self.strings[string] = StringIntMapEntry(string, num)
 471
 472     def bake(self):
 473         self.sorted_strings = \
 474             sorted(self.strings.values(), key=lambda x: x.string)
 475         offset = 0
 476         for entry in self.sorted_strings:
 477             entry.offset = offset
 478             offset += len(entry.string) + 1
 479
 480         # Save off some values that we'll need in C
 481         self.hash_size = round_to_pow2(len(self.strings) * 1.25)
 482         self.hash_mask = self.hash_size - 1
 483         self.prime_factor = PRIME_FACTOR
 484         self.prime_step = PRIME_STEP
 485
 486         self.mapping = [-1] * self.hash_size
 487         self.collisions = [0] * 10
 488         for idx, s in enumerate(self.sorted_strings):
 489             level = 0
 490             h = s.hash
 491             while self.mapping[h & self.hash_mask] >= 0:
 492                 h = h + PRIME_STEP
 493                 level = level + 1
 494             self.collisions[min(level, 9)] += 1
 495             self.mapping[h & self.hash_mask] = idx
 496
 497 EntrypointParam = namedtuple('EntrypointParam', 'type name decl')
 498
 499 class EntrypointBase(object):
 500     def __init__(self, name):
 501         self.name = name
 502         self.alias = None
 503         self.guard = None
 504         self.enabled = False
 505         self.num = None
 506         # Extensions which require this entrypoint
 507         self.core_version = None
 508         self.extensions = []
 509
 510 class Entrypoint(EntrypointBase):
 511     def __init__(self, name, return_type, params, guard = None):
 512         super(Entrypoint, self).__init__(name)
 513         self.return_type = return_type
 514         self.params = params
 515         self.guard = guard
 516
 517     def is_device_entrypoint(self):
 518         return self.params[0].type in ('VkDevice', 'VkCommandBuffer', 'VkQueue')
 519
 520     def prefixed_name(self, prefix):
 521         assert self.name.startswith('vk')
 522         return prefix + '_' + self.name[2:]
 523
 524     def decl_params(self):
 525         return ', '.join(p.decl for p in self.params)
 526
 527     def call_params(self):
 528         return ', '.join(p.name for p in self.params)
 529
 530 class EntrypointAlias(EntrypointBase):
 531     def __init__(self, name, entrypoint):
 532         super(EntrypointAlias, self).__init__(name)
 533         self.alias = entrypoint
 534
 535     def is_device_entrypoint(self):
 536         return self.alias.is_device_entrypoint()
 537
 538     def prefixed_name(self, prefix):
 539         return self.alias.prefixed_name(prefix)
 540
 541 def get_entrypoints(doc, entrypoints_to_defines, start_index):
 542     """Extract the entry points from the registry."""
 543     entrypoints = OrderedDict()
 544
 545     for command in doc.findall('./commands/command'):
 546         if 'alias' in command.attrib:
 547             alias = command.attrib['name']
 548             target = command.attrib['alias']
 549             entrypoints[alias] = EntrypointAlias(alias, entrypoints[target])
 550         else:
 551             name = command.find('./proto/name').text
 552             ret_type = command.find('./proto/type').text
 553             params = [EntrypointParam(
 554                 type = p.find('./type').text,
 555                 name = p.find('./name').text,
 556                 decl = ''.join(p.itertext())
 557             ) for p in command.findall('./param')]
 558             guard = entrypoints_to_defines.get(name)
 559             # They really need to be unique
 560             assert name not in entrypoints
 561             entrypoints[name] = Entrypoint(name, ret_type, params, guard)
 562
 563     for feature in doc.findall('./feature'):
 564         assert feature.attrib['api'] == 'vulkan'
 565         version = VkVersion(feature.attrib['number'])
 566         if version > MAX_API_VERSION:
 567             continue
 568
 569         for command in feature.findall('./require/command'):
 570             e = entrypoints[command.attrib['name']]
 571             e.enabled = True
 572             assert e.core_version is None
 573             e.core_version = version
 574
 575     supported_exts = dict((ext.name, ext) for ext in EXTENSIONS)
 576     for extension in doc.findall('.extensions/extension'):
 577         ext_name = extension.attrib['name']
 578         if ext_name not in supported_exts:
 579             continue
 580
 581         ext = supported_exts[ext_name]
 582         ext.type = extension.attrib['type']
 583
 584         for command in extension.findall('./require/command'):
 585             e = entrypoints[command.attrib['name']]
 586             e.enabled = True
 587             assert e.core_version is None
 588             e.extensions.append(ext)
 589
 590     return [e for e in entrypoints.values() if e.enabled]
 591
 592
 593 def get_entrypoints_defines(doc):
 594     """Maps entry points to extension defines."""
 595     entrypoints_to_defines = {}
 596
 597     for extension in doc.findall('./extensions/extension[@platform]'):
 598         platform = extension.attrib['platform']
 599         ext = '_KHR'
 600         if platform.upper() == 'XLIB_XRANDR':
 601             ext = '_EXT'
 602         define = 'VK_USE_PLATFORM_' + platform.upper() + ext
 603
 604         for entrypoint in extension.findall('./require/command'):
 605             fullname = entrypoint.attrib['name']
 606             entrypoints_to_defines[fullname] = define
 607
 608     return entrypoints_to_defines
 609
 610
 611 def main():
 612     parser = argparse.ArgumentParser()
 613     parser.add_argument('--outdir', help='Where to write the files.',
 614                         required=True)
 615     parser.add_argument('--xml',
 616                         help='Vulkan API XML file.',
 617                         required=True,
 618                         action='append',
 619                         dest='xml_files')
 620     args = parser.parse_args()
 621
 622     entrypoints = []
 623
 624     for filename in args.xml_files:
 625         doc = et.parse(filename)
 626         entrypoints += get_entrypoints(doc, get_entrypoints_defines(doc),
 627                                        start_index=len(entrypoints))
 628
 629     # Manually add CreateDmaBufImageINTEL for which we don't have an extension
 630     # defined.
 631     entrypoints.append(Entrypoint('vkCreateDmaBufImageINTEL', 'VkResult', [
 632         EntrypointParam('VkDevice', 'device', 'VkDevice device'),
 633         EntrypointParam('VkDmaBufImageCreateInfo', 'pCreateInfo',
 634                         'const VkDmaBufImageCreateInfo* pCreateInfo'),
 635         EntrypointParam('VkAllocationCallbacks', 'pAllocator',
 636                         'const VkAllocationCallbacks* pAllocator'),
 637         EntrypointParam('VkDeviceMemory', 'pMem', 'VkDeviceMemory* pMem'),
 638         EntrypointParam('VkImage', 'pImage', 'VkImage* pImage')
 639     ]))
 640
 641     device_entrypoints = []
 642     instance_entrypoints = []
 643     for e in entrypoints:
 644         if e.is_device_entrypoint():
 645             device_entrypoints.append(e)
 646         else:
 647             instance_entrypoints.append(e)
 648
 649     device_strmap = StringIntMap()
 650     for num, e in enumerate(device_entrypoints):
 651         device_strmap.add_string(e.name, num)
 652         e.num = num
 653     device_strmap.bake()
 654
 655     instance_strmap = StringIntMap()
 656     for num, e in enumerate(instance_entrypoints):
 657         instance_strmap.add_string(e.name, num)
 658         e.num = num
 659     instance_strmap.bake()
 660
 661     # For outputting entrypoints.h we generate a anv_EntryPoint() prototype
 662     # per entry point.
 663     try:
 664         with open(os.path.join(args.outdir, 'anv_entrypoints.h'), 'wb') as f:
 665             f.write(TEMPLATE_H.render(instance_entrypoints=instance_entrypoints,
 666                                       device_entrypoints=device_entrypoints,
 667                                       LAYERS=LAYERS,
 668                                       filename=os.path.basename(__file__)))
 669         with open(os.path.join(args.outdir, 'anv_entrypoints.c'), 'wb') as f:
 670             f.write(TEMPLATE_C.render(instance_entrypoints=instance_entrypoints,
 671                                       device_entrypoints=device_entrypoints,
 672                                       LAYERS=LAYERS,
 673                                       instance_strmap=instance_strmap,
 674                                       device_strmap=device_strmap,
 675                                       filename=os.path.basename(__file__)))
 676     except Exception:
 677         # In the even there's an error this imports some helpers from mako
 678         # to print a useful stack trace and prints it, then exits with
 679         # status 1, if python is run with debug; otherwise it just raises
 680         # the exception
 681         if __debug__:
 682             import sys
 683             from mako import exceptions
 684             sys.stderr.write(exceptions.text_error_template().render() + '\n')
 685             sys.exit(1)
 686         raise
 687
 688
 689 if __name__ == '__main__':
 690     main()