Wrap every place that accesses a dispatch table with a macro. A new script-

generated file, called src/mesa/glapi/dispatch.h, is added.  This file
contains three macros for each API function.  It contains a GET, a SET, and
a CALL.  Each of the macros take a pointer to the context and a pointer to
the dispatch table.

In several threads on mesa3d-dev we discussed replacing _glapi_add_entrypoint
with a new function called _glapi_add_dispatch.  For this discussion, the
important difference between the two is that the caller of _glapi_add_dispatch
does *not* know what the dispatch offset will be at compile time.  Because of
this callers need to track the dispatch offset returned by
_glapi_add_dispatch.

http://marc.theaimsgroup.com/?t=111947074700001&r=1&w=2

The downside is that driver code then has to access the dispatch table two
different ways.  It accesses it using structure tags (e.g., exec->Begin) for
functions with fixed offsets and via a remap table (e.g., exec[
remap->NewExtensionFunction ]) for functions without fixed offsets. Yuck!

Using the macros allows both types of functions to be accessed
identically.  If a driver needs to set a pointer for Begin, it does
'SET_Begin(ctx, exec, my_begin_function)'.  If it needs to set a pointer
for NewExtensionFunction, it does 'SET_NewExtensionFunction(ctx, exec,
my_NewExtensionFunction_function)'.  Furthermore, if at some point in
the future a static offset is assigned for NewExtensionFunction, only
the macros need to change (instead of every single place that accesses a
table for that function).

This code differs slightly from the originally posted patches in that the
CALL, GET, and SET marcos no longer take a context pointer as a parameter.
Brian Paul had suggested that the remap table could be stored as a global
since it would be set at CreateScreen time and would be constant for all
contexts.  This change reflects that feedback.

http://marc.theaimsgroup.com/?t=112087194700001&r=1&w=2

3 files changed, 102 insertions, 12 deletions

diff --git a/src/mesa/glapi/Makefile b/src/mesa/glapi/Makefile
index db3d0ca3901..259f3910c5c 100644
--- a/src/mesa/glapi/Makefile
+++ b/src/mesa/glapi/Makefile
@@ -7,7 +7,7 @@
 TOP = ../../..
 include $(TOP)/configs/current
 
-OUTPUTS = glprocs.h glapitemp.h glapioffsets.h glapitable.h \
+OUTPUTS = glprocs.h glapitemp.h glapioffsets.h glapitable.h dispatch.h \
 	../main/enums.c \
 	../x86/glapi_x86.S \
 	../drivers/dri/common/extension_helper.h \
@@ -34,6 +34,9 @@ glapioffsets.h: $(COMMON) gl_offsets.py
 glapitable.h: $(COMMON) gl_table.py
 	$(PYTHON2) $(PYTHON_FLAGS) gl_table.py > glapitable.h
 
+dispatch.h: $(COMMON) gl_table.py
+	$(PYTHON2) $(PYTHON_FLAGS) gl_table.py -m remap_table > dispatch.h
+
 ../main/enums.c: $(COMMON) gl_enums.py
 	$(PYTHON2) $(PYTHON_FLAGS) gl_enums.py > ../main/enums.c
 
diff --git a/src/mesa/glapi/gl_table.py b/src/mesa/glapi/gl_table.py
index a3b49438b70..d585b43cde5 100644
--- a/src/mesa/glapi/gl_table.py
+++ b/src/mesa/glapi/gl_table.py
@@ -62,23 +62,110 @@ class PrintGlTable(gl_XML.gl_print_base):
 		return
 
 
+class PrintRemapTable(gl_XML.gl_print_base):
+	def __init__(self):
+		gl_XML.gl_print_base.__init__(self)
+
+		self.header_tag = '_DISPATCH_H_'
+		self.name = "gl_table.py (from Mesa)"
+		self.license = license.bsd_license_template % ("(C) Copyright IBM Corporation 2005", "IBM")
+		return
+
+
+	def printRealHeader(self):
+		print """/**
+ * \\file dispatch.h
+ * Macros for handling GL dispatch tables.
+ *
+ * For each known GL function, there are 3 macros in this file.  The first
+ * macro is named CALL_FuncName and is used to call that GL function using
+ * the specified dispatch table.  The other 2 macros, called GET_FuncName
+ * can SET_FuncName, are used to get and set the dispatch pointer for the
+ * named function in the specified dispatch table.
+ */
+"""
+		
+		return
+
+	def printBody(self, api):
+		print '#define CALL_by_offset(disp, cast, offset, parameters) \\'
+		print '    (*(cast (((_glapi_proc *)(disp))[offset]))) parameters'
+		print '#define GET_by_offset(disp, offset) \\'
+		print '    (((_glapi_proc *)(disp))[offset])'
+		print '#define SET_by_offset(disp, offset, fn) \\'
+		print '    ((((_glapi_proc *)(disp))[offset]) = fn)'
+		print ''
+
+		for f in api.functionIterateByOffset():
+			print '#define CALL_%s(disp, parameters) (*((disp)->%s)) parameters' % (f.name, f.name)
+			print '#define GET_%s(disp) ((disp)->%s)' % (f.name, f.name)
+			print '#define SET_%s(disp, fn) ((disp)->%s = fn)' % (f.name, f.name)
+		return
+
+		abi = [ "1.0", "1.1", "1.2", "GL_ARB_multitexture" ]
+
+		functions = []
+		abi_functions = []
+		count = 0
+		for f in api.functionIterateByOffset():
+			[category, num] = api.get_category_for_name( f.name )
+			if category not in abi:
+				functions.append( [f, count] )
+				count += 1
+			else:
+				abi_functions.append( f )
+
+
+		print 'struct _mesa_dispatch_remap_table {'
+
+		for [f, index] in functions:
+			print '   unsigned %s;' % (f.name)
+
+		print '};'
+		print ''
+		print '/* %u functions need remapping. */' % (count)
+		print ''
+
+		for f in abi_functions:
+			print '#define CALL_%s(disp, parameters) (*disp->%s) parameters' % (f.name, f.name)
+
+
+		for [f, index] in functions:
+			arg_string = gl_XML.create_parameter_string( f.parameters, 0 )
+			cast = '%s (GLAPIENTRYP)(%s)' % (f.return_type, arg_string)
+
+			print '#define CALL_%s(disp, parameters) (* (%s) (((_glapi_proc *)disp)[dispatch_remap.%s])) parameters' % (f.name, cast, f.name)
+
+		return
+
+
 def show_usage():
-	print "Usage: %s [-f input_file_name]" % sys.argv[0]
+	print "Usage: %s [-f input_file_name] [-m mode]" % sys.argv[0]
+	print "    -m mode   Mode can be 'table' or 'remap_table'."
 	sys.exit(1)
 
 if __name__ == '__main__':
 	file_name = "gl_API.xml"
     
 	try:
-		(args, trail) = getopt.getopt(sys.argv[1:], "f:")
+		(args, trail) = getopt.getopt(sys.argv[1:], "f:m:")
 	except Exception,e:
 		show_usage()
 
+	mode = "table"
 	for (arg,val) in args:
 		if arg == "-f":
 			file_name = val
+		elif arg == "-m":
+			mode = val
+
+	if mode == "table":
+		printer = PrintGlTable()
+	elif mode == "remap_table":
+		printer = PrintRemapTable()
+	else:
+		show_usage()
 
 	api = gl_XML.parse_GL_API( file_name )
 
-	printer = PrintGlTable()
 	printer.Print( api )
diff --git a/src/mesa/glapi/glthread.h b/src/mesa/glapi/glthread.h
index 291485dc205..503bb44abdf 100644
--- a/src/mesa/glapi/glthread.h
+++ b/src/mesa/glapi/glthread.h
@@ -119,9 +119,9 @@ typedef pthread_mutex_t _glthread_Mutex;
 extern struct _glapi_table * _glapi_DispatchTSD;
 extern _glthread_TSD _gl_DispatchTSD;
 
-#define GL_CALL(name) \
-   (((__builtin_expect( _glapi_DispatchTSD != NULL, 1 )) \
-	? _glapi_DispatchTSD : (struct _glapi_table *) pthread_getspecific(_gl_DispatchTSD.key))-> name)
+#define GET_DISPATCH() \
+   ((__builtin_expect( _glapi_DispatchTSD != NULL, 1 )) \
+       ? _glapi_DispatchTSD : (struct _glapi_table *) pthread_getspecific(_gl_DispatchTSD.key))
 #endif
 
 #endif /* PTHREADS */
@@ -312,16 +312,16 @@ _glthread_SetTSD(_glthread_TSD *, void *);
 extern __thread struct _glapi_table * _glapi_tls_Dispatch
     __attribute__((tls_model("initial-exec")));
 
-# define GL_CALL(name) (*(_glapi_tls_Dispatch-> name))
+#define GET_DISPATCH() _glapi_tls_Dispatch
 
 #elif !defined(GL_CALL)
 # if defined(THREADS)
 extern struct _glapi_table * _glapi_DispatchTSD;
-#  define GL_CALL(name) \
-   (((__builtin_expect( _glapi_DispatchTSD != NULL, 1 )) \
-	? _glapi_DispatchTSD : _glapi_get_dispatch())-> name)
+#  define GET_DISPATCH() \
+   ((__builtin_expect( _glapi_DispatchTSD != NULL, 1 )) \
+       ? _glapi_DispatchTSD : _glapi_get_dispatch())
 # else
-#  define GL_CALL(name) (*(_glapi_Dispatch-> name))
+#  define GET_DISPATCH() _glapi_Dispatch
 # endif /* defined(THREADS) */
 #endif  /* ndef GL_CALL */