107 lines
2.9 KiB
Python
107 lines
2.9 KiB
Python
# Copyright 2016 Google Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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"""A code generator that emits C code."""
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import sys
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from . import lex
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from . import parser
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from . import ir
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from . import util
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class CGenerator:
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def __init__(self):
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pass
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def emit_program(self, program):
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self.cmd('#include "pl0.h"')
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self.note(program)
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self.dispatch(program.operations)
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def dispatch(self, node):
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if isinstance(node, list) or isinstance(node, tuple):
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for item in node:
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self.dispatch(item)
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else:
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target = 'emit_{}'.format(util.typename(node))
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self.note('Invoking {}({})'.format(target, node))
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return getattr(self, target)(node)
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def emit_note(self, note):
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self.note(note.text)
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def emit_reserve(self, reserve):
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self.cmd('int_t {};'.format(reserve.val))
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def emit_enter(self, enter):
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self.cmd('void {}() {{'.format(enter.val))
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def emit_assign(self, assign):
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self.cmd(
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'{} = {};'.format(assign.result.lvalue(), assign.left.rvalue()))
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def emit_exit(self, exit_):
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self.cmd('}')
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def emit_label(self, label):
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self.cmd('{}: ;'.format(label.val))
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def emit_const(self, const):
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self.cmd('const int_t {} = {};'.format(const.name, const.val))
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def emit_condition(self, cond):
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self.emit_operation(cond)
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def emit_if(self, ifcmd):
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self.cmd('if (!{}) goto {};'.format(ifcmd.left, ifcmd.target.val))
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def emit_goto(self, goto):
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self.cmd('goto {};'.format(goto.val.val))
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def emit_operation(self, operation):
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self.cmd('{} = {} {} {};'.format(operation.result.lvalue(),
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operation.left.rvalue(), operation.
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operation, operation.right.rvalue()))
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def emit_call(self, call):
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if call.arg is not None:
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self.cmd('{}({});'.format(call.name, call.arg))
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else:
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self.cmd('{}();'.format(call.name))
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def cmd(self, msg: str):
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print(msg)
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def note(self, msg: str):
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print('// {}'.format(msg))
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def codegen(program):
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program.dump('top')
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irgen = ir.IRGenerator()
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irf = irgen.dispatch(program)
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cgen = CGenerator()
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gen = cgen.dispatch(irf)
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def main():
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program = parser.parse(lex.lex(sys.stdin.read()))
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codegen(program)
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if __name__ == '__main__':
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main()
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