61 lines
2 KiB
Python
61 lines
2 KiB
Python
#!/usr/bin/env python
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# Import the llvm-py modules.
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from llvm import *
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from llvm.core import *
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import logging
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import unittest
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class TestExample(unittest.TestCase):
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def test_example(self):
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# Create an (empty) module.
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my_module = Module.new('my_module')
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# All the types involved here are "int"s. This type is represented
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# by an object of the llvm.core.Type class:
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ty_int = Type.int() # by default 32 bits
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# We need to represent the class of functions that accept two integers
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# and return an integer. This is represented by an object of the
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# function type (llvm.core.FunctionType):
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ty_func = Type.function(ty_int, [ty_int, ty_int])
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# Now we need a function named 'sum' of this type. Functions are not
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# free-standing (in llvm-py); it needs to be contained in a module.
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f_sum = my_module.add_function(ty_func, "sum")
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self.assertEqual(str(f_sum).strip(), 'declare i32 @sum(i32, i32)')
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# Let's name the function arguments as 'a' and 'b'.
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f_sum.args[0].name = "a"
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f_sum.args[1].name = "b"
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# Our function needs a "basic block" -- a set of instructions that
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# end with a terminator (like return, branch etc.). By convention
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# the first block is called "entry".
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bb = f_sum.append_basic_block("entry")
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# Let's add instructions into the block. For this, we need an
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# instruction builder:
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builder = Builder.new(bb)
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# OK, now for the instructions themselves. We'll create an add
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# instruction that returns the sum as a value, which we'll use
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# a ret instruction to return.
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tmp = builder.add(f_sum.args[0], f_sum.args[1], "tmp")
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self.assertEqual(str(tmp).strip(), '%tmp = add i32 %a, %b')
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builder.ret(tmp)
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# We've completed the definition now! Let's see the LLVM assembly
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# language representation of what we've created:
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logging.debug(my_module)
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if __name__ == '__main__':
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unittest.main()
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