foundationdb/bindings/c/generate_asm.py

139 lines
4.6 KiB
Python
Executable File

#!/usr/bin/env python
#
# generate_asm.py
#
# This source file is part of the FoundationDB open source project
#
# Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import re
import sys
(platform, source, asm, h) = sys.argv[1:]
functions = {}
func_re = re.compile(
"^\s*FDB_API_(?:CHANGED|REMOVED)\s*\(\s*([^,]*),\s*([^)]*)\).*")
with open(source, 'r') as srcfile:
for l in srcfile:
m = func_re.match(l)
if m:
func, ver = m.groups()
if func not in functions:
functions[func] = []
ver = int(ver)
if ver not in functions[func]:
functions[func].append(ver)
def write_windows_asm(asmfile, functions):
asmfile.write(".data\n")
for f in functions:
asmfile.write("\textern fdb_api_ptr_%s:qword\n" % f)
asmfile.write("\n.code\n")
for f in functions:
asmfile.write("\n%s proc EXPORT\n" % f)
asmfile.write("\tmov r11, qword ptr [fdb_api_ptr_%s]\n" % f)
asmfile.write("\tjmp r11\n")
asmfile.write("%s endp\n" % f)
asmfile.write("\nEND\n")
def write_unix_asm(asmfile, functions, prefix):
if platform != "linux-aarch64":
asmfile.write(".intel_syntax noprefix\n")
if platform.startswith('linux') or platform == "freebsd":
asmfile.write("\n.data\n")
for f in functions:
asmfile.write("\t.extern fdb_api_ptr_%s\n" % f)
asmfile.write("\n.text\n")
for f in functions:
asmfile.write("\t.global %s\n\t.type %s, @function\n" % (f, f))
for f in functions:
asmfile.write("\n.globl %s%s\n" % (prefix, f))
asmfile.write("%s%s:\n" % (prefix, f))
# These assembly implementations of versioned fdb c api functions must have the following properties.
#
# 1. Don't require dynamic relocation.
#
# 2. Perform a tail-call to the function pointer that works for a
# function with any number of arguments. For example, since registers x0-x7 are used
# to pass arguments in the Arm calling convention we must not use x0-x7
# here.
#
# You can compile this example c program to get a rough idea of how to
# load the extern symbol and make a tail call.
#
# $ cat test.c
# typedef int (*function)();
# extern function f;
# int g() { return f(); }
# $ cc -S -O3 -fPIC test.c && grep -A 10 '^g:' test.[sS]
# g:
# .LFB0:
# .cfi_startproc
# adrp x0, :got:f
# ldr x0, [x0, #:got_lo12:f]
# ldr x0, [x0]
# br x0
# .cfi_endproc
# .LFE0:
# .size g, .-g
# .ident "GCC: (GNU) 8.3.1 20190311 (Red Hat 8.3.1-3)"
if platform == "linux-aarch64":
asmfile.write("\tadrp x8, :got:fdb_api_ptr_%s\n" % (f))
asmfile.write("\tldr x8, [x8, #:got_lo12:fdb_api_ptr_%s]\n" % (f))
asmfile.write("\tldr x8, [x8]\n")
asmfile.write("\tbr x8\n")
else:
asmfile.write(
"\tmov r11, qword ptr [%sfdb_api_ptr_%s@GOTPCREL+rip]\n" % (prefix, f))
asmfile.write("\tmov r11, qword ptr [r11]\n")
asmfile.write("\tjmp r11\n")
with open(asm, 'w') as asmfile:
with open(h, 'w') as hfile:
hfile.write(
"void fdb_api_ptr_unimpl() { fprintf(stderr, \"UNIMPLEMENTED FDB API FUNCTION\\n\"); abort(); }\n\n")
hfile.write(
"void fdb_api_ptr_removed() { fprintf(stderr, \"REMOVED FDB API FUNCTION\\n\"); abort(); }\n\n")
if platform.startswith('linux'):
write_unix_asm(asmfile, functions, '')
elif platform == "osx":
write_unix_asm(asmfile, functions, '_')
elif platform == "windows":
write_windows_asm(asmfile, functions)
for f in functions:
if platform == "windows":
hfile.write("extern \"C\" ")
hfile.write("void* fdb_api_ptr_%s = (void*)&fdb_api_ptr_unimpl;\n" % f)
for v in functions[f]:
hfile.write("#define %s_v%d_PREV %s_v%d\n" % (f, v, f, v - 1))