Completed editing of PythonLangImpl4.rst
This commit is contained in:
Maggie Mari
parent
1b67d32f4b
commit
f74f5129bd
1 changed files with 437 additions and 356 deletions
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@ -187,9 +187,7 @@ by running it after our newly created function is constructed (in
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return_value = self.body.CodeGen()
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g_llvm_builder.ret(return_value)
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::
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# Validate the generated code, checking for consistency.
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function.verify()
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@ -403,22 +401,28 @@ example, we can create a C file with the following simple function:
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#include <stdio.h>
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double putchard(double x) {
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putchar((char)x); return 0; }
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putchar((char)x); return 0;
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}
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We can then compile this into a shared library with GCC:
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We can then compile this into a shared library with GCC::
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gcc -shared -fPIC -o putchard.so putchard.c
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Now we can load this library into the Python process using
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``llvm.core.load_library_permanently`` and access it from Kaleidoscope
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to produce simple output to the console:
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>>> import llvm.core >>>
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llvm.core.load_library_permanently('/home/max/llvmpy-tutorial/putchard.so')
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>>> import kaleidoscope >>> kaleidoscope.main() ready> extern
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putchard(x) Read an extern: declare double @putchard(double)
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ready> putchard(65) + putchard(66) + putchard(67) + putchard(10) *ABC*
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Now we can load this library into the Python process using
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``llvm.core.load_library_permanently`` and access it from Kaleidoscope
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to produce simple output to the console::
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>>> import llvm.core
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>>> llvm.core.load_library_permanently('/home/max/llvmpy-tutorial/putchard.so')
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>>> import kaleidoscope
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>>> kaleidoscope.main()
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ready> extern putchard(x)
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Read an extern:
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declare double @putchard(double)
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ready> putchard(65) + putchard(66) + putchard(67) + putchard(10)
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*ABC*
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Evaluated to: 0.0
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@ -446,14 +450,19 @@ the LLVM JIT and optimizer:
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#!/usr/bin/env python
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import re from llvm.core import Module, Constant, Type, Function,
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Builder, FCMP_ULT from llvm.ee import ExecutionEngine, TargetData from
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llvm.passes import FunctionPassManager from llvm.passes import
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(PASS_INSTRUCTION_COMBINING, PASS_REASSOCIATE, PASS_GVN,
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PASS_CFG_SIMPLIFICATION)
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import re
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from llvm.core import Module, Constant, Type, Function, Builder, FCMP_ULT
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from llvm.ee import ExecutionEngine, TargetData
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from llvm.passes import FunctionPassManager
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from llvm.passes import (PASS_INSTRUCTION_COMBINING,
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PASS_REASSOCIATE,
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PASS_GVN,
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PASS_CFG_SIMPLIFICATION)
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Globals
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-------
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Globals
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-------
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.. code-block:: python
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# The LLVM module, which holds all the IR code.
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g_llvm_module = Module.new('my cool jit')
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@ -471,385 +480,457 @@ the LLVM JIT and optimizer:
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# The LLVM execution engine.
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g_llvm_executor = ExecutionEngine.new(g_llvm_module)
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Lexer
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-----
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Lexer
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-----
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.. code-block:: python
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# The lexer yields one of these types for each token.
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class EOFToken(object): pass
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class EOFToken(object):
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pass
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class DefToken(object): pass
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class DefToken(object):
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pass
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class ExternToken(object): pass
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class ExternToken(object):
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pass
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class IdentifierToken(object): def __init__(self, name): self.name =
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name
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class IdentifierToken(object):
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def __init__(self, name):
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self.name = name
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class NumberToken(object): def __init__(self, value): self.value =
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value
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class NumberToken(object):
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def __init__(self, value):
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self.value = value
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class CharacterToken(object): def __init__(self, char): self.char =
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char def __eq__(self, other): return isinstance(other, CharacterToken)
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and self.char == other.char def __ne__(self, other): return not self
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== other
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class CharacterToken(object):
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def __init__(self, char):
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self.char = char
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def __eq__(self, other):
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return isinstance(other, CharacterToken) and self.char == other.char
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def __ne__(self, other):
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return not self == other
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# Regular expressions that tokens and comments of our language.
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REGEX_NUMBER = re.compile('[0-9]+(?:.[0-9]+)?') REGEX_IDENTIFIER =
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re.compile('[a-zA-Z][a-zA-Z0-9]\ *') REGEX_COMMENT = re.compile('#.*')
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def Tokenize(string): while string: # Skip whitespace. if
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string[0].isspace(): string = string[1:] continue
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::
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# Run regexes.
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comment_match = REGEX_COMMENT.match(string)
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number_match = REGEX_NUMBER.match(string)
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identifier_match = REGEX_IDENTIFIER.match(string)
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# Check if any of the regexes matched and yield the appropriate result.
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if comment_match:
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comment = comment_match.group(0)
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string = string[len(comment):]
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elif number_match:
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number = number_match.group(0)
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yield NumberToken(float(number))
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string = string[len(number):]
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elif identifier_match:
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identifier = identifier_match.group(0)
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# Check if we matched a keyword.
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if identifier == 'def':
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yield DefToken()
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elif identifier == 'extern':
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yield ExternToken()
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else:
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yield IdentifierToken(identifier)
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string = string[len(identifier):]
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else:
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# Yield the ASCII value of the unknown character.
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yield CharacterToken(string[0])
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string = string[1:]
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REGEX_NUMBER = re.compile('[0-9]+(?:.[0-9]+)?')
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REGEX_IDENTIFIER = re.compile('[a-zA-Z][a-zA-Z0-9]\ *')
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REGEX_COMMENT = re.compile('#.*')
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def Tokenize(string):
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while string:
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# Skip whitespace.
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if string[0].isspace():
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string = string[1:]
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continue
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# Run regexes.
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comment_match = REGEX_COMMENT.match(string)
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number_match = REGEX_NUMBER.match(string)
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identifier_match = REGEX_IDENTIFIER.match(string)
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# Check if any of the regexes matched and yield the appropriate result.
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if comment_match:
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comment = comment_match.group(0)
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string = string[len(comment):]
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elif number_match:
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number = number_match.group(0)
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yield NumberToken(float(number))
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string = string[len(number):]
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elif identifier_match:
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identifier = identifier_match.group(0)
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# Check if we matched a keyword.
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if identifier == 'def':
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yield DefToken()
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elif identifier == 'extern':
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yield ExternToken()
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else:
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yield IdentifierToken(identifier)
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string = string[len(identifier):]
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else:
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# Yield the ASCII value of the unknown character.
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yield CharacterToken(string[0])
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string = string[1:]
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yield EOFToken()
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Abstract Syntax Tree (aka Parse Tree)
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-------------------------------------
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Abstract Syntax Tree (aka Parse Tree)
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-------------------------------------
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.. code-block:: python
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# Base class for all expression nodes.
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class ExpressionNode(object): pass
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class ExpressionNode(object):
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pass
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# Expression class for numeric literals like "1.0".
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class NumberExpressionNode(ExpressionNode):
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def __init__(self, value): self.value = value
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def CodeGen(self): return Constant.real(Type.double(), self.value)
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def __init__(self, value):
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self.value = value
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def CodeGen(self):
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return Constant.real(Type.double(), self.value)
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# Expression class for referencing a variable, like "a".
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class VariableExpressionNode(ExpressionNode):
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def __init__(self, name): self.name = name
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def CodeGen(self): if self.name in g_named_values: return
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g_named_values[self.name] else: raise RuntimeError('Unknown variable
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name: ' + self.name)
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def __init__(self, name):
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self.name = name
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def CodeGen(self):
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if self.name in g_named_values:
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return g_named_values[self.name]
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else:
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raise RuntimeError('Unknown variable name: ' + self.name)
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# Expression class for a binary operator.
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class BinaryOperatorExpressionNode(ExpressionNode):
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def __init__(self, operator, left, right): self.operator = operator
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self.left = left self.right = right
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def CodeGen(self): left = self.left.CodeGen() right =
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self.right.CodeGen()
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::
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if self.operator == '+':
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return g_llvm_builder.fadd(left, right, 'addtmp')
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elif self.operator == '-':
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return g_llvm_builder.fsub(left, right, 'subtmp')
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elif self.operator == '*':
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return g_llvm_builder.fmul(left, right, 'multmp')
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elif self.operator == '<':
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result = g_llvm_builder.fcmp(FCMP_ULT, left, right, 'cmptmp')
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# Convert bool 0 or 1 to double 0.0 or 1.0.
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return g_llvm_builder.uitofp(result, Type.double(), 'booltmp')
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else:
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raise RuntimeError('Unknown binary operator.')
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def __init__(self, operator, left, right):
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self.operator = operator
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self.left = left
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self.right = right
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def CodeGen(self):
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left = self.left.CodeGen()
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right = self.right.CodeGen()
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if self.operator == '+':
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return g_llvm_builder.fadd(left, right, 'addtmp')
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elif self.operator == '-':
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return g_llvm_builder.fsub(left, right, 'subtmp')
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elif self.operator == '*':
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return g_llvm_builder.fmul(left, right, 'multmp')
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elif self.operator == '<':
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result = g_llvm_builder.fcmp(FCMP_ULT, left, right, 'cmptmp')
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# Convert bool 0 or 1 to double 0.0 or 1.0.
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return g_llvm_builder.uitofp(result, Type.double(), 'booltmp')
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else:
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raise RuntimeError('Unknown binary operator.')
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# Expression class for function calls.
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class CallExpressionNode(ExpressionNode):
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def __init__(self, callee, args): self.callee = callee self.args =
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args
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def CodeGen(self): # Look up the name in the global module table. callee
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= g_llvm_module.get_function_named(self.callee)
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::
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# Check for argument mismatch error.
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if len(callee.args) != len(self.args):
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raise RuntimeError('Incorrect number of arguments passed.')
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arg_values = [i.CodeGen() for i in self.args]
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return g_llvm_builder.call(callee, arg_values, 'calltmp')
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def __init__(self, callee, args):
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self.callee = callee
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self.args = args
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def CodeGen(self):
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# Look up the name in the global module table.
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callee = g_llvm_module.get_function_named(self.callee)
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# Check for argument mismatch error.
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if len(callee.args) != len(self.args):
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raise RuntimeError('Incorrect number of arguments passed.')
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arg_values = [i.CodeGen() for i in self.args]
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return g_llvm_builder.call(callee, arg_values, 'calltmp')
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# This class represents the "prototype" for a function, which captures its name,
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# and its argument names (thus implicitly the number of arguments the function
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# takes).
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class PrototypeNode(object):
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def __init__(self, name, args): self.name = name self.args = args
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def __init__(self, name, args):
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self.name = name
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self.args = args
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def CodeGen(self): # Make the function type, eg. double(double,double).
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funct_type = Type.function( Type.double(), [Type.double()] \*
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len(self.args), False)
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::
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function = Function.new(g_llvm_module, funct_type, self.name)
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# If the name conflicted, there was already something with the same name.
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# If it has a body, don't allow redefinition or reextern.
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if function.name != self.name:
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function.delete()
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function = g_llvm_module.get_function_named(self.name)
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# If the function already has a body, reject this.
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if not function.is_declaration:
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raise RuntimeError('Redefinition of function.')
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# If F took a different number of args, reject.
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if len(callee.args) != len(self.args):
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raise RuntimeError('Redeclaration of a function with different number '
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'of args.')
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# Set names for all arguments and add them to the variables symbol table.
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for arg, arg_name in zip(function.args, self.args):
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arg.name = arg_name
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# Add arguments to variable symbol table.
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g_named_values[arg_name] = arg
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return function
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def CodeGen(self):
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# Make the function type, eg. double(double,double).
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funct_type = Type.function(
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Type.double(), [Type.double()] * len(self.args), False)
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function = Function.new(g_llvm_module, funct_type, self.name)
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# If the name conflicted, there was already something with the same name.
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# If it has a body, don't allow redefinition or reextern.
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if function.name != self.name:
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function.delete()
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function = g_llvm_module.get_function_named(self.name)
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# If the function already has a body, reject this.
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if not function.is_declaration:
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raise RuntimeError('Redefinition of function.')
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# If F took a different number of args, reject.
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if len(callee.args) != len(self.args):
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raise RuntimeError('Redeclaration of a function with different number '
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'of args.')
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# Set names for all arguments and add them to the variables symbol table.
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for arg, arg_name in zip(function.args, self.args):
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arg.name = arg_name
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# Add arguments to variable symbol table.
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g_named_values[arg_name] = arg
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return function
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# This class represents a function definition itself.
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class FunctionNode(object):
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def __init__(self, prototype, body): self.prototype = prototype
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self.body = body
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def __init__(self, prototype, body):
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self.prototype = prototype
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self.body = body
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def CodeGen(self):
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# Clear scope.
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g_named_values.clear()
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# Create a function object.
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function = self.prototype.CodeGen()
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# Create a new basic block to start insertion into.
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block = function.append_basic_block('entry')
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global g_llvm_builder
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g_llvm_builder = Builder.new(block)
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# Finish off the function.
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try:
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return_value = self.body.CodeGen()
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g_llvm_builder.ret(return_value)
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# Validate the generated code, checking for consistency.
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function.verify()
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# Optimize the function.
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g_llvm_pass_manager.run(function)
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except:
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function.delete()
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raise
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return function
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def CodeGen(self): # Clear scope. g_named_values.clear()
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::
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# Create a function object.
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function = self.prototype.CodeGen()
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# Create a new basic block to start insertion into.
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block = function.append_basic_block('entry')
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global g_llvm_builder
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g_llvm_builder = Builder.new(block)
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# Finish off the function.
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try:
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return_value = self.body.CodeGen()
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g_llvm_builder.ret(return_value)
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# Validate the generated code, checking for consistency.
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function.verify()
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# Optimize the function.
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g_llvm_pass_manager.run(function)
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except:
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function.delete()
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raise
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return function
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Parser
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||||
------
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Parser
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||||
------
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.. code-block:: python
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class Parser(object):
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def __init__(self, tokens, binop_precedence): self.tokens = tokens
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self.binop_precedence = binop_precedence self.Next()
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def __init__(self, tokens, binop_precedence):
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self.tokens = tokens
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self.binop_precedence = binop_precedence
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self.Next()
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# Provide a simple token buffer. Parser.current is the current token the
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# parser is looking at. Parser.Next() reads another token from the lexer and
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# updates Parser.current with its results.
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def Next(self):
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self.current = self.tokens.next()
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||||
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||||
# Gets the precedence of the current token, or -1 if the token is not a
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||||
binary # operator.
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def GetCurrentTokenPrecedence(self):
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||||
if isinstance(self.current, CharacterToken):
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return self.binop_precedence.get(self.current.char, -1)
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else:
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return -1
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# identifierexpr ::= identifier | identifier '(' expression* ')'
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def ParseIdentifierExpr(self):
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||||
identifier_name = self.current.name
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||||
self.Next() # eat identifier.
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||||
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||||
if self.current != CharacterToken('('): # Simple variable reference.
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return VariableExpressionNode(identifier_name)
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# Call.
|
||||
self.Next() # eat '('.
|
||||
args = []
|
||||
if self.current != CharacterToken(')'):
|
||||
while True:
|
||||
args.append(self.ParseExpression())
|
||||
if self.current == CharacterToken(')'):
|
||||
break
|
||||
elif self.current != CharacterToken(','):
|
||||
raise RuntimeError('Expected ")" or "," in argument list.')
|
||||
self.Next()
|
||||
|
||||
self.Next() # eat ')'.
|
||||
return CallExpressionNode(identifier_name, args)
|
||||
|
||||
# numberexpr ::= number
|
||||
def ParseNumberExpr(self):
|
||||
result = NumberExpressionNode(self.current.value)
|
||||
self.Next() # consume the number.
|
||||
return result
|
||||
|
||||
# parenexpr ::= '(' expression ')'
|
||||
def ParseParenExpr(self):
|
||||
self.Next() # eat '('.
|
||||
|
||||
contents = self.ParseExpression()
|
||||
|
||||
if self.current != CharacterToken(')'):
|
||||
raise RuntimeError('Expected ")".')
|
||||
self.Next() # eat ')'.
|
||||
|
||||
return contents
|
||||
|
||||
# primary ::= identifierexpr | numberexpr | parenexpr
|
||||
def ParsePrimary(self):
|
||||
if isinstance(self.current, IdentifierToken):
|
||||
return self.ParseIdentifierExpr()
|
||||
elif isinstance(self.current, NumberToken):
|
||||
return self.ParseNumberExpr()
|
||||
elif self.current == CharacterToken('('):
|
||||
return self.ParseParenExpr()
|
||||
else: raise RuntimeError('Unknown token when expecting an expression.')
|
||||
|
||||
# binoprhs ::= (operator primary)*
|
||||
def ParseBinOpRHS(self, left, left_precedence):
|
||||
# If this is a binary operator, find its precedence.
|
||||
while True:
|
||||
precedence = self.GetCurrentTokenPrecedence()
|
||||
|
||||
# If this is a binary operator that binds at least as tightly as the
|
||||
# current one, consume it; otherwise we are done.
|
||||
if precedence < left_precedence:
|
||||
return left
|
||||
|
||||
binary_operator = self.current.char
|
||||
self.Next() # eat the operator.
|
||||
|
||||
# Parse the primary expression after the binary operator.
|
||||
right = self.ParsePrimary()
|
||||
|
||||
# If binary_operator binds less tightly with right than the operator after
|
||||
# right, let the pending operator take right as its left.
|
||||
next_precedence = self.GetCurrentTokenPrecedence()
|
||||
if precedence < next_precedence:
|
||||
right = self.ParseBinOpRHS(right, precedence + 1)
|
||||
|
||||
# Merge left/right.
|
||||
left = BinaryOperatorExpressionNode(binary_operator, left, right)
|
||||
|
||||
# expression ::= primary binoprhs
|
||||
def ParseExpression(self):
|
||||
left = self.ParsePrimary()
|
||||
return self.ParseBinOpRHS(left, 0)
|
||||
|
||||
# prototype ::= id '(' id* ')'
|
||||
def ParsePrototype(self):
|
||||
if not isinstance(self.current, IdentifierToken):
|
||||
raise RuntimeError('Expected function name in prototype.')
|
||||
|
||||
function_name = self.current.name
|
||||
self.Next() # eat function name.
|
||||
|
||||
if self.current != CharacterToken('('):
|
||||
raise RuntimeError('Expected "(" in prototype.')
|
||||
self.Next() # eat '('.
|
||||
|
||||
arg_names = []
|
||||
while isinstance(self.current, IdentifierToken):
|
||||
arg_names.append(self.current.name)
|
||||
self.Next()
|
||||
|
||||
if self.current != CharacterToken(')'):
|
||||
raise RuntimeError('Expected ")" in prototype.')
|
||||
|
||||
# Success.
|
||||
self.Next() # eat ')'.
|
||||
|
||||
return PrototypeNode(function_name, arg_names)
|
||||
|
||||
# definition ::= 'def' prototype expression
|
||||
def ParseDefinition(self):
|
||||
self.Next() # eat def.
|
||||
proto = self.ParsePrototype()
|
||||
body = self.ParseExpression()
|
||||
return FunctionNode(proto, body)
|
||||
|
||||
# toplevelexpr ::= expression
|
||||
def ParseTopLevelExpr(self):
|
||||
proto = PrototypeNode('', [])
|
||||
return FunctionNode(proto, self.ParseExpression())
|
||||
|
||||
# external ::= 'extern' prototype
|
||||
def ParseExtern(self):
|
||||
self.Next() # eat extern.
|
||||
return self.ParsePrototype()
|
||||
|
||||
# Top-Level parsing
|
||||
def HandleDefinition(self):
|
||||
self.Handle(self.ParseDefinition, 'Read a function definition:')
|
||||
|
||||
def HandleExtern(self):
|
||||
self.Handle(self.ParseExtern, 'Read an extern:')
|
||||
|
||||
def HandleTopLevelExpression(self):
|
||||
try:
|
||||
function = self.ParseTopLevelExpr().CodeGen()
|
||||
result = g_llvm_executor.run_function(function, [])
|
||||
print 'Evaluated to:', result.as_real(Type.double())
|
||||
except Exception, e:
|
||||
print 'Error:', e
|
||||
try:
|
||||
self.Next() # Skip for error recovery.
|
||||
except:
|
||||
pass
|
||||
|
||||
def Handle(self, function, message):
|
||||
try:
|
||||
print message, function().CodeGen()
|
||||
except Exception, e:
|
||||
print 'Error:', e
|
||||
try:
|
||||
self.Next() # Skip for error recovery.
|
||||
except:
|
||||
pass
|
||||
|
||||
# Provide a simple token buffer. Parser.current is the current token the
|
||||
# parser is looking at. Parser.Next() reads another token from the lexer
|
||||
and # updates Parser.current with its results. def Next(self):
|
||||
self.current = self.tokens.next()
|
||||
Main driver code.
|
||||
-----------------
|
||||
|
||||
.. code-block:: python
|
||||
|
||||
# Gets the precedence of the current token, or -1 if the token is not a
|
||||
binary # operator. def GetCurrentTokenPrecedence(self): if
|
||||
isinstance(self.current, CharacterToken): return
|
||||
self.binop_precedence.get(self.current.char, -1) else: return -1
|
||||
def main():
|
||||
# Set up the optimizer pipeline. Start with registering info about how the
|
||||
# target lays out data structures.
|
||||
g_llvm_pass_manager.add(g_llvm_executor.target_data)
|
||||
# Do simple "peephole" optimizations and bit-twiddling optzns.
|
||||
g_llvm_pass_manager.add(PASS_INSTRUCTION_COMBINING)
|
||||
# Reassociate expressions.
|
||||
g_llvm_pass_manager.add(PASS_REASSOCIATE)
|
||||
# Eliminate Common SubExpressions.
|
||||
g_llvm_pass_manager.add(PASS_GVN)
|
||||
# Simplify the control flow graph (deleting unreachable blocks, etc).
|
||||
g_llvm_pass_manager.add(PASS_CFG_SIMPLIFICATION)
|
||||
|
||||
g_llvm_pass_manager.initialize()
|
||||
|
||||
# Install standard binary operators.
|
||||
# 1 is lowest possible precedence. 40 is the highest.
|
||||
operator_precedence = {
|
||||
'<': 10,
|
||||
'+': 20,
|
||||
'-': 20,
|
||||
'\*': 40
|
||||
}
|
||||
|
||||
# Run the main "interpreter loop".
|
||||
while True:
|
||||
print 'ready>',
|
||||
try:
|
||||
raw = raw_input()
|
||||
except KeyboardInterrupt:
|
||||
break
|
||||
|
||||
parser = Parser(Tokenize(raw), operator_precedence)
|
||||
while True:
|
||||
# top ::= definition | external | expression | EOF
|
||||
if isinstance(parser.current, EOFToken):
|
||||
break
|
||||
if isinstance(parser.current, DefToken):
|
||||
parser.HandleDefinition()
|
||||
elif isinstance(parser.current, ExternToken):
|
||||
parser.HandleExtern()
|
||||
else:
|
||||
parser.HandleTopLevelExpression()
|
||||
|
||||
# Print out all of the generated code.
|
||||
print '', g_llvm_module
|
||||
|
||||
# identifierexpr ::= identifier \| identifier '(' expression\* ')' def
|
||||
ParseIdentifierExpr(self): identifier_name = self.current.name
|
||||
self.Next() # eat identifier.
|
||||
|
||||
::
|
||||
|
||||
if self.current != CharacterToken('('): # Simple variable reference.
|
||||
return VariableExpressionNode(identifier_name)
|
||||
|
||||
# Call.
|
||||
self.Next() # eat '('.
|
||||
args = []
|
||||
if self.current != CharacterToken(')'):
|
||||
while True:
|
||||
args.append(self.ParseExpression())
|
||||
if self.current == CharacterToken(')'):
|
||||
break
|
||||
elif self.current != CharacterToken(','):
|
||||
raise RuntimeError('Expected ")" or "," in argument list.')
|
||||
self.Next()
|
||||
|
||||
self.Next() # eat ')'.
|
||||
return CallExpressionNode(identifier_name, args)
|
||||
|
||||
# numberexpr ::= number def ParseNumberExpr(self): result =
|
||||
NumberExpressionNode(self.current.value) self.Next() # consume the
|
||||
number. return result
|
||||
|
||||
# parenexpr ::= '(' expression ')' def ParseParenExpr(self): self.Next()
|
||||
# eat '('.
|
||||
|
||||
::
|
||||
|
||||
contents = self.ParseExpression()
|
||||
|
||||
if self.current != CharacterToken(')'):
|
||||
raise RuntimeError('Expected ")".')
|
||||
self.Next() # eat ')'.
|
||||
|
||||
return contents
|
||||
|
||||
# primary ::= identifierexpr \| numberexpr \| parenexpr def
|
||||
ParsePrimary(self): if isinstance(self.current, IdentifierToken): return
|
||||
self.ParseIdentifierExpr() elif isinstance(self.current, NumberToken):
|
||||
return self.ParseNumberExpr() elif self.current == CharacterToken('('):
|
||||
return self.ParseParenExpr() else: raise RuntimeError('Unknown token
|
||||
when expecting an expression.')
|
||||
|
||||
# binoprhs ::= (operator primary)\* def ParseBinOpRHS(self, left,
|
||||
left_precedence): # If this is a binary operator, find its precedence.
|
||||
while True: precedence = self.GetCurrentTokenPrecedence()
|
||||
|
||||
::
|
||||
|
||||
# If this is a binary operator that binds at least as tightly as the
|
||||
# current one, consume it; otherwise we are done.
|
||||
if precedence < left_precedence:
|
||||
return left
|
||||
|
||||
binary_operator = self.current.char
|
||||
self.Next() # eat the operator.
|
||||
|
||||
# Parse the primary expression after the binary operator.
|
||||
right = self.ParsePrimary()
|
||||
|
||||
# If binary_operator binds less tightly with right than the operator after
|
||||
# right, let the pending operator take right as its left.
|
||||
next_precedence = self.GetCurrentTokenPrecedence()
|
||||
if precedence < next_precedence:
|
||||
right = self.ParseBinOpRHS(right, precedence + 1)
|
||||
|
||||
# Merge left/right.
|
||||
left = BinaryOperatorExpressionNode(binary_operator, left, right)
|
||||
|
||||
# expression ::= primary binoprhs def ParseExpression(self): left =
|
||||
self.ParsePrimary() return self.ParseBinOpRHS(left, 0)
|
||||
|
||||
# prototype ::= id '(' id\* ')' def ParsePrototype(self): if not
|
||||
isinstance(self.current, IdentifierToken): raise RuntimeError('Expected
|
||||
function name in prototype.')
|
||||
|
||||
::
|
||||
|
||||
function_name = self.current.name
|
||||
self.Next() # eat function name.
|
||||
|
||||
if self.current != CharacterToken('('):
|
||||
raise RuntimeError('Expected "(" in prototype.')
|
||||
self.Next() # eat '('.
|
||||
|
||||
arg_names = []
|
||||
while isinstance(self.current, IdentifierToken):
|
||||
arg_names.append(self.current.name)
|
||||
self.Next()
|
||||
|
||||
if self.current != CharacterToken(')'):
|
||||
raise RuntimeError('Expected ")" in prototype.')
|
||||
|
||||
# Success.
|
||||
self.Next() # eat ')'.
|
||||
|
||||
return PrototypeNode(function_name, arg_names)
|
||||
|
||||
# definition ::= 'def' prototype expression def ParseDefinition(self):
|
||||
self.Next() # eat def. proto = self.ParsePrototype() body =
|
||||
self.ParseExpression() return FunctionNode(proto, body)
|
||||
|
||||
# toplevelexpr ::= expression def ParseTopLevelExpr(self): proto =
|
||||
PrototypeNode('', []) return FunctionNode(proto, self.ParseExpression())
|
||||
|
||||
# external ::= 'extern' prototype def ParseExtern(self): self.Next() #
|
||||
eat extern. return self.ParsePrototype()
|
||||
|
||||
# Top-Level parsing def HandleDefinition(self):
|
||||
self.Handle(self.ParseDefinition, 'Read a function definition:')
|
||||
|
||||
def HandleExtern(self): self.Handle(self.ParseExtern, 'Read an extern:')
|
||||
|
||||
def HandleTopLevelExpression(self): try: function =
|
||||
self.ParseTopLevelExpr().CodeGen() result =
|
||||
g_llvm_executor.run_function(function, []) print 'Evaluated to:',
|
||||
result.as_real(Type.double()) except Exception, e: print 'Error:', e
|
||||
try: self.Next() # Skip for error recovery. except: pass
|
||||
|
||||
def Handle(self, function, message): try: print message,
|
||||
function().CodeGen() except Exception, e: print 'Error:', e try:
|
||||
self.Next() # Skip for error recovery. except: pass
|
||||
|
||||
Main driver code.
|
||||
-----------------
|
||||
|
||||
def main(): # Set up the optimizer pipeline. Start with registering info
|
||||
about how the # target lays out data structures.
|
||||
g_llvm_pass_manager.add(g_llvm_executor.target_data) # Do simple
|
||||
"peephole" optimizations and bit-twiddling optzns.
|
||||
g_llvm_pass_manager.add(PASS_INSTRUCTION_COMBINING) # Reassociate
|
||||
expressions. g_llvm_pass_manager.add(PASS_REASSOCIATE) # Eliminate
|
||||
Common SubExpressions. g_llvm_pass_manager.add(PASS_GVN) # Simplify
|
||||
the control flow graph (deleting unreachable blocks, etc).
|
||||
g_llvm_pass_manager.add(PASS_CFG_SIMPLIFICATION)
|
||||
|
||||
g_llvm_pass_manager.initialize()
|
||||
|
||||
# Install standard binary operators. # 1 is lowest possible precedence.
|
||||
40 is the highest. operator_precedence = { '<': 10, '+': 20, '-': 20,
|
||||
'\*': 40 }
|
||||
|
||||
# Run the main "interpreter loop". while True: print 'ready>', try: raw
|
||||
= raw_input() except KeyboardInterrupt: break
|
||||
|
||||
::
|
||||
|
||||
parser = Parser(Tokenize(raw), operator_precedence)
|
||||
while True:
|
||||
# top ::= definition | external | expression | EOF
|
||||
if isinstance(parser.current, EOFToken):
|
||||
break
|
||||
if isinstance(parser.current, DefToken):
|
||||
parser.HandleDefinition()
|
||||
elif isinstance(parser.current, ExternToken):
|
||||
parser.HandleExtern()
|
||||
else:
|
||||
parser.HandleTopLevelExpression()
|
||||
|
||||
# Print out all of the generated code. print '', g_llvm_module
|
||||
|
||||
if **name** == '__main__': main()
|
||||
if __name__ == '__main__':
|
||||
main()
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue