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# Copyright 2014 David Malcolm <dmalcolm@redhat.com>
# Copyright 2014 Red Hat, Inc.
#
# This is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see
# <http://www.gnu.org/licenses/>.
"""
This examples creates and runs the equivalent of this C function:
int square(int i)
{
return i * i;
}
"""
import ctypes
import gccjit
def create_fn():
# Create a compilation context:
ctxt = gccjit.Context()
# Turn these on to get various kinds of debugging:
if 0:
ctxt.set_bool_option(gccjit.BoolOption.DUMP_INITIAL_TREE, True)
ctxt.set_bool_option(gccjit.BoolOption.DUMP_INITIAL_GIMPLE, True)
ctxt.set_bool_option(gccjit.BoolOption.DUMP_GENERATED_CODE, True)
# Adjust this to control optimization level of the generated code:
if 0:
ctxt.set_int_option(gccjit.IntOption.OPTIMIZATION_LEVEL, 3)
int_type = ctxt.get_type(gccjit.TypeKind.INT)
# Create parameter "i":
param_i = ctxt.new_param(int_type, b'i')
# Create the function:
fn = ctxt.new_function(gccjit.FunctionKind.EXPORTED,
int_type,
b"square",
[param_i])
# Create a basic block within the function:
block = fn.new_block(b'entry')
# This basic block is relatively simple:
block.end_with_return(
ctxt.new_binary_op(gccjit.BinaryOp.MULT,
int_type,
param_i, param_i))
# Having populated the context, compile it.
jit_result = ctxt.compile()
# This is what you get back from ctxt.compile():
assert isinstance(jit_result, gccjit.Result)
return jit_result
def test_calling_fn(i):
jit_result = create_fn()
# Look up a specific machine code routine within the gccjit.Result,
# in this case, the function we created above:
void_ptr = jit_result.get_code(b"square")
# Now use ctypes.CFUNCTYPE to turn it into something we can call
# from Python:
int_int_func_type = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_int)
code = int_int_func_type(void_ptr)
# Now try running the code:
return code(i)
if __name__ == '__main__':
print(test_calling_fn(5))
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