mesa/src/mapi/glapi/gen/gl_gentable.py
Arlie Davis daa775b58e mesa: Reduce libGL.so binary size by about 15%
This patch significantly reduces the size of the libGL.so binary. It does
not change the (externally visible) behavior of libGL.so at all.

gl_gentable.py generates a function, _glapi_create_table_from_handle.
This function allocates a large dispatch table, consisting of 1300 or so
function pointers, and fills this dispatch table by doing symbol lookups
on a given shared library.  Previously, gl_gentable.py would generate a
single, very large _glapi_create_table_from_handle function, with a short
cluster of lines for each entry point (function).  The idiom it generates
was a NULL check, a call to snprintf, a call to dlsym / GetProcAddress,
and then a store into the dispatch table.  Since this function processes
a large number of entry points, this code is duplicated many times over.

We can encode the same information much more compactly, by using a lookup
table.  The previous total size of _glapi_create_table_from_handle on x64
was 125848 bytes.  By using a lookup table, the size of
_glapi_create_table_from_handle (and the related lookup tables) is reduced
to 10840 bytes.  In other words, this enormous function is reduced by 91%.
The size of the entire libGL.so binary (measured when stripped) itself drops
by 15%.

So the purpose of this change is to reduce the binary size, which frees up
disk space, memory, etc.

size lib/libGL.so.1.2.0 on my system shows (Andreas)
   text	   data	    bss	    dec	    hex	filename
 565947	  11256	   2720	 579923	  8d953	lib/libGL.so.1.2.0 before
 469211	  21848	   2720	 493779	  788d3	lib/libGL.so.1.2.0 after

v2: Incorporate Matt's feedback.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
Tested-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
Signed-off-by: Andreas Boll <andreas.boll.dev@gmail.com>
2016-01-21 15:03:53 +01:00

239 lines
6.6 KiB
Python

#!/usr/bin/env python
# (C) Copyright IBM Corporation 2004, 2005
# (C) Copyright Apple Inc. 2011
# Copyright (C) 2015 Intel Corporation
# All Rights Reserved.
#
# 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
# on 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
# IBM 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.
#
# Authors:
# Jeremy Huddleston <jeremyhu@apple.com>
#
# Based on code ogiginally by:
# Ian Romanick <idr@us.ibm.com>
import argparse
import license
import gl_XML, glX_XML
header = """/* GLXEXT is the define used in the xserver when the GLX extension is being
* built. Hijack this to determine whether this file is being built for the
* server or the client.
*/
#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif
#if (defined(GLXEXT) && defined(HAVE_BACKTRACE)) \\
|| (!defined(GLXEXT) && defined(DEBUG) && !defined(__CYGWIN__) && !defined(__MINGW32__) && !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__DragonFly__))
#define USE_BACKTRACE
#endif
#ifdef USE_BACKTRACE
#include <execinfo.h>
#endif
#ifndef _WIN32
#include <dlfcn.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#include "main/glheader.h"
#include "glapi.h"
#include "glapitable.h"
#ifdef GLXEXT
#include "os.h"
#endif
static void
__glapi_gentable_NoOp(void) {
const char *fstr = "Unknown";
/* Silence potential GCC warning for some #ifdef paths.
*/
(void) fstr;
#if defined(USE_BACKTRACE)
#if !defined(GLXEXT)
if (getenv("MESA_DEBUG") || getenv("LIBGL_DEBUG"))
#endif
{
void *frames[2];
if(backtrace(frames, 2) == 2) {
Dl_info info;
dladdr(frames[1], &info);
if(info.dli_sname)
fstr = info.dli_sname;
}
#if !defined(GLXEXT)
fprintf(stderr, "Call to unimplemented API: %s\\n", fstr);
#endif
}
#endif
#if defined(GLXEXT)
LogMessage(X_ERROR, "GLX: Call to unimplemented API: %s\\n", fstr);
#endif
}
static void
__glapi_gentable_set_remaining_noop(struct _glapi_table *disp) {
GLuint entries = _glapi_get_dispatch_table_size();
void **dispatch = (void **) disp;
unsigned i;
/* ISO C is annoying sometimes */
union {_glapi_proc p; void *v;} p;
p.p = __glapi_gentable_NoOp;
for(i=0; i < entries; i++)
if(dispatch[i] == NULL)
dispatch[i] = p.v;
}
"""
footer = """
struct _glapi_table *
_glapi_create_table_from_handle(void *handle, const char *symbol_prefix) {
struct _glapi_table *disp = calloc(_glapi_get_dispatch_table_size(), sizeof(_glapi_proc));
char symboln[512];
if(!disp)
return NULL;
if(symbol_prefix == NULL)
symbol_prefix = "";
/* Note: This code relies on _glapi_table_func_names being sorted by the
* entry point index of each function.
*/
for (int func_index = 0; func_index < GLAPI_TABLE_COUNT; ++func_index) {
const char *name = _glapi_table_func_names[func_index];
void ** procp = &((void **)disp)[func_index];
snprintf(symboln, sizeof(symboln), \"%s%s\", symbol_prefix, name);
#ifdef _WIN32
*procp = GetProcAddress(handle, symboln);
#else
*procp = dlsym(handle, symboln);
#endif
}
__glapi_gentable_set_remaining_noop(disp);
return disp;
}
"""
class PrintCode(gl_XML.gl_print_base):
def __init__(self):
gl_XML.gl_print_base.__init__(self)
self.name = "gl_gentable.py (from Mesa)"
self.license = license.bsd_license_template % ( \
"""Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
(C) Copyright IBM Corporation 2004, 2005
(C) Copyright Apple Inc 2011""", "BRIAN PAUL, IBM")
return
def get_stack_size(self, f):
size = 0
for p in f.parameterIterator():
if p.is_padding:
continue
size += p.get_stack_size()
return size
def printRealHeader(self):
print header
return
def printRealFooter(self):
print footer
return
def printBody(self, api):
# Determine how many functions have a defined offset.
func_count = 0
for f in api.functions_by_name.itervalues():
if f.offset != -1:
func_count += 1
# Build the mapping from offset to function name.
funcnames = [None] * func_count
for f in api.functions_by_name.itervalues():
if f.offset != -1:
if not (funcnames[f.offset] is None):
raise Exception("Function table has more than one function with same offset (offset %d, func %s)" % (f.offset, f.name))
funcnames[f.offset] = f.name
# Check that the table has no gaps. We expect a function at every offset,
# and the code which generates the table relies on this.
for i in xrange(0, func_count):
if funcnames[i] is None:
raise Exception("Function table has no function at offset %d" % (i))
print "#define GLAPI_TABLE_COUNT %d" % func_count
print "static const char * const _glapi_table_func_names[GLAPI_TABLE_COUNT] = {"
for i in xrange(0, func_count):
print " /* %5d */ \"%s\"," % (i, funcnames[i])
print "};"
return
def _parser():
"""Parse arguments and return a namespace object."""
parser = argparse.ArgumentParser()
parser.add_argument('-f',
dest='filename',
default='gl_API.xml',
help='An XML file description of an API')
return parser.parse_args()
def main():
"""Main function."""
args = _parser()
printer = PrintCode()
api = gl_XML.parse_GL_API(args.filename, glX_XML.glx_item_factory())
printer.Print(api)
if __name__ == '__main__':
main()