Finished editing PythonLangImpl5.rst
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Maggie Mari
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1 changed files with 167 additions and 124 deletions
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@ -114,13 +114,13 @@ To represent the new expression we add a new AST node for it:
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# Expression class for if/then/else.
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class IfExpressionNode(ExpressionNode):
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def __init__(self, condition, then_branch, else_branch):
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self.condition = condition
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self.then_branch = then_branch
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self.else_branch = else_branch
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def CodeGen(self):
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...
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def __init__(self, condition, then_branch, else_branch):
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self.condition = condition
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self.then_branch = then_branch
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self.else_branch = else_branch
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def CodeGen(self):
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...
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@ -1257,7 +1257,8 @@ Parser
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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 self.Next()
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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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@ -1279,7 +1280,7 @@ Parser
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self.Next() # eat identifier.
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if self.current != CharacterToken('('): # Simple variable reference.
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return VariableExpressionNode(identifier_name)
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return VariableExpressionNode(identifier_name)
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# Call.
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self.Next() # eat '('.
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@ -1375,131 +1376,173 @@ Parser
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return ForExpressionNode(loop_variable, start, end, step, body)
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# primary ::= identifierexpr | numberexpr | parenexpr | ifexpr |
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forexpr def ParsePrimary(self): if isinstance(self.current,
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IdentifierToken): return self.ParseIdentifierExpr() elif
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isinstance(self.current, NumberToken): return self.ParseNumberExpr()
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elif isinstance(self.current, IfToken): return self.ParseIfExpr() elif
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isinstance(self.current, ForToken): return self.ParseForExpr() elif
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self.current == CharacterToken('('): return self.ParseParenExpr() else:
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raise RuntimeError('Unknown token when expecting an expression.')
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# primary ::= identifierexpr | numberexpr | parenexpr | ifexpr | forexpr
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def ParsePrimary(self):
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if isinstance(self.current, IdentifierToken):
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return self.ParseIdentifierExpr()
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elif isinstance(self.current, NumberToken):
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return self.ParseNumberExpr()
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elif isinstance(self.current, IfToken):
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return self.ParseIfExpr()
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elif isinstance(self.current, ForToken):
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return self.ParseForExpr()
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elif self.current == CharacterToken('('):
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return self.ParseParenExpr()
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else:
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raise RuntimeError('Unknown token when expecting an expression.')
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# binoprhs ::= (operator primary)* def ParseBinOpRHS(self, left,
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left_precedence): # If this is a binary operator, find its precedence.
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while True: precedence = self.GetCurrentTokenPrecedence()
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# binoprhs ::= (operator primary)*
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def ParseBinOpRHS(self, left, left_precedence):
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# If this is a binary operator, find its precedence.
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while True:
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precedence = self.GetCurrentTokenPrecedence()
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# If this is a binary operator that binds at least as tightly as the
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# current one, consume it; otherwise we are done.
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if precedence < left_precedence:
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return left
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binary_operator = self.current.char
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self.Next() # eat the operator.
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# Parse the primary expression after the binary operator.
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right = self.ParsePrimary()
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# If binary_operator binds less tightly with right than the operator after
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# right, let the pending operator take right as its left.
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next_precedence = self.GetCurrentTokenPrecedence()
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if precedence < next_precedence:
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right = self.ParseBinOpRHS(right, precedence + 1)
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# Merge left/right.
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left = BinaryOperatorExpressionNode(binary_operator, left, right)
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::
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# expression ::= primary binoprhs
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def ParseExpression(self):
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left = self.ParsePrimary()
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return self.ParseBinOpRHS(left, 0)
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# If this is a binary operator that binds at least as tightly as the
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# current one, consume it; otherwise we are done.
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if precedence < left_precedence:
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return left
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# prototype ::= id '(' id* ')'
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def ParsePrototype(self):
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if not isinstance(self.current, IdentifierToken):
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raise RuntimeError('Expected function name in prototype.')
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function_name = self.current.name
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self.Next() # eat function name.
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if self.current != CharacterToken('('):
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raise RuntimeError('Expected "(" in prototype.')
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self.Next() # eat '('.
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arg_names = []
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while isinstance(self.current, IdentifierToken):
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arg_names.append(self.current.name)
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self.Next()
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if self.current != CharacterToken(')'):
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raise RuntimeError('Expected ")" in prototype.')
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# Success.
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self.Next() # eat ')'.
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return PrototypeNode(function_name, arg_names)
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binary_operator = self.current.char
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self.Next() # eat the operator.
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# definition ::= 'def' prototype expression
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def ParseDefinition(self):
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self.Next() # eat def.
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proto = self.ParsePrototype()
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body = self.ParseExpression()
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return FunctionNode(proto, body)
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# Parse the primary expression after the binary operator.
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right = self.ParsePrimary()
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# toplevelexpr ::= expression
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def ParseTopLevelExpr(self):
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proto = PrototypeNode('', [])
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return FunctionNode(proto, self.ParseExpression())
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# If binary_operator binds less tightly with right than the operator after
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# right, let the pending operator take right as its left.
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next_precedence = self.GetCurrentTokenPrecedence()
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if precedence < next_precedence:
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right = self.ParseBinOpRHS(right, precedence + 1)
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# external ::= 'extern' prototype
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def ParseExtern(self):
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self.Next() # eat extern.
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return self.ParsePrototype()
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# Merge left/right.
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left = BinaryOperatorExpressionNode(binary_operator, left, right)
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# Top-Level parsing
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def HandleDefinition(self):
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self.Handle(self.ParseDefinition, 'Read a function definition:')
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# expression ::= primary binoprhs def ParseExpression(self): left =
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self.ParsePrimary() return self.ParseBinOpRHS(left, 0)
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def HandleExtern(self):
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self.Handle(self.ParseExtern, 'Read an extern:')
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# prototype ::= id '(' id* ')' def ParsePrototype(self): if not
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isinstance(self.current, IdentifierToken): raise RuntimeError('Expected
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function name in prototype.')
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def HandleTopLevelExpression(self):
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try:
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function = self.ParseTopLevelExpr().CodeGen()
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result = g_llvm_executor.run_function(function, [])
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print 'Evaluated to:', result.as_real(Type.double())
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except Exception, e:
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print 'Error:', e
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try:
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self.Next() # Skip for error recovery.
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except:
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pass
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::
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function_name = self.current.name
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self.Next() # eat function name.
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if self.current != CharacterToken('('):
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raise RuntimeError('Expected "(" in prototype.')
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self.Next() # eat '('.
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arg_names = []
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while isinstance(self.current, IdentifierToken):
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arg_names.append(self.current.name)
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self.Next()
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if self.current != CharacterToken(')'):
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raise RuntimeError('Expected ")" in prototype.')
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# Success.
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self.Next() # eat ')'.
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return PrototypeNode(function_name, arg_names)
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# definition ::= 'def' prototype expression def ParseDefinition(self):
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self.Next() # eat def. proto = self.ParsePrototype() body =
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self.ParseExpression() return FunctionNode(proto, body)
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# toplevelexpr ::= expression def ParseTopLevelExpr(self): proto =
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PrototypeNode('', []) return FunctionNode(proto, self.ParseExpression())
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# external ::= 'extern' prototype def ParseExtern(self): self.Next() #
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eat extern. return self.ParsePrototype()
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# Top-Level parsing def HandleDefinition(self):
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self.Handle(self.ParseDefinition, 'Read a function definition:')
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def HandleExtern(self): self.Handle(self.ParseExtern, 'Read an extern:')
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def HandleTopLevelExpression(self): try: function =
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self.ParseTopLevelExpr().CodeGen() result =
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g_llvm_executor.run_function(function, []) print 'Evaluated to:',
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result.as_real(Type.double()) except Exception, e: print 'Error:', e
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try: self.Next() # Skip for error recovery. except: pass
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def Handle(self, function, message): try: print message,
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function().CodeGen() except Exception, e: print 'Error:', e try:
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self.Next() # Skip for error recovery. except: pass
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def Handle(self, function, message):
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try:
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print message, function().CodeGen()
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except Exception, e:
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print 'Error:', e
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try:
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self.Next() # Skip for error recovery.
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except:
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pass
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Main driver code.
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-----------------
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Main driver code.
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-----------------
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.. code-block:: python
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def main(): # Set up the optimizer pipeline. Start with registering info
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about how the # target lays out data structures.
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g_llvm_pass_manager.add(g_llvm_executor.target_data) # Do simple
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"peephole" optimizations and bit-twiddling optzns.
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g_llvm_pass_manager.add(PASS_INSTRUCTION_COMBINING) # Reassociate
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expressions. g_llvm_pass_manager.add(PASS_REASSOCIATE) # Eliminate
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Common SubExpressions. g_llvm_pass_manager.add(PASS_GVN) # Simplify
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the control flow graph (deleting unreachable blocks, etc).
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g_llvm_pass_manager.add(PASS_CFG_SIMPLIFICATION)
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def main():
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# Set up the optimizer pipeline. Start with registering info about how the
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# target lays out data structures.
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g_llvm_pass_manager.add(g_llvm_executor.target_data)
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# Do simple "peephole" optimizations and bit-twiddling optzns.
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g_llvm_pass_manager.add(PASS_INSTRUCTION_COMBINING)
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# Reassociate expressions.
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g_llvm_pass_manager.add(PASS_REASSOCIATE)
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# Eliminate Common SubExpressions.
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g_llvm_pass_manager.add(PASS_GVN)
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# Simplify the control flow graph (deleting unreachable blocks, etc).
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g_llvm_pass_manager.add(PASS_CFG_SIMPLIFICATION)
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g_llvm_pass_manager.initialize()
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# Install standard binary operators.
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# 1 is lowest possible precedence. 40 is the highest.
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operator_precedence = {
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'<': 10,
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'+': 20,
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'-': 20,
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'*': 40
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}
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# Run the main "interpreter loop".
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while True:
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print 'ready>',
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try:
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raw = raw_input()
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except KeyboardInterrupt:
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break
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parser = Parser(Tokenize(raw), operator_precedence)
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while True:
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# top ::= definition | external | expression | EOF
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if isinstance(parser.current, EOFToken):
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break
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if isinstance(parser.current, DefToken):
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parser.HandleDefinition()
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elif isinstance(parser.current, ExternToken):
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parser.HandleExtern()
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else:
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parser.HandleTopLevelExpression()
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# Print out all of the generated code. print '', g_llvm_module
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g_llvm_pass_manager.initialize()
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# Install standard binary operators. # 1 is lowest possible precedence.
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40 is the highest. operator_precedence = { '<': 10, '+': 20, '-': 20,
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'*': 40 }
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# Run the main "interpreter loop". while True: print 'ready>', try: raw
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= raw_input() except KeyboardInterrupt: break
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::
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parser = Parser(Tokenize(raw), operator_precedence)
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while True:
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# top ::= definition | external | expression | EOF
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if isinstance(parser.current, EOFToken):
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break
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if isinstance(parser.current, DefToken):
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parser.HandleDefinition()
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elif isinstance(parser.current, ExternToken):
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parser.HandleExtern()
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else:
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parser.HandleTopLevelExpression()
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# Print out all of the generated code. print '', g_llvm_module
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if **name** == '__main__': main()
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if __name__ == '__main__':
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main()
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