py2cfg.CFGBuilder

class documentation

class CFGBuilder(ast.NodeVisitor): (source)

Control flow graph builder. A control flow graph builder is an ast.NodeVisitor that can walk through a program's AST and iteratively build the corresponding CFG.

Method	`__init__`	Undocumented
Method	`add_exit`	Add a new exit to a block.
Method	`add_statement`	Add a statement to a block.
Method	`build`	Build a CFG from an AST.
Method	`build_from_file`	Build a CFG from some Python source file.
Method	`build_from_src`	Build a CFG from some Python source code.
Method	`clean_cfg`	Remove the useless (empty) blocks from a CFG.
Method	`new_block`	Create a new block with a new id.
Method	`new_classCFG`	Create a new sub-CFG for a class definition and add it to the class CFGs of the CFG being built.
Method	`new_func_block`	Create a new function block with a new id.
Method	`new_functionCFG`	Create a new sub-CFG for a function definition and add it to the function CFGs of the CFG being built.
Method	`new_loopguard`	Create a new block for a loop's guard if the current block is not empty. Links the current block to the new loop guard.
Method	`new_try_block`	Undocumented
Method	`visit_AnnAssign`	Undocumented
Method	`visit_Assert`	Undocumented
Method	`visit_Assign`	Undocumented
Method	`visit_AsyncFunctionDef`	Undocumented
Method	`visit_AugAssign`	Undocumented
Method	`visit_Await`	Undocumented
Method	`visit_Break`	Undocumented
Method	`visit_Call`	Undocumented
Method	`visit_ClassDef`	Undocumented
Method	`visit_Continue`	Undocumented
Method	`visit_ExceptHandler`	Undocumented
Method	`visit_Expr`	Undocumented
Method	`visit_For`	Undocumented
Method	`visit_FunctionDef`	Undocumented
Method	`visit_If`	Undocumented
Method	`visit_Import`	Undocumented
Method	`visit_ImportFrom`	Undocumented
Method	`visit_Raise`	Undocumented
Method	`visit_Return`	Undocumented
Method	`visit_Try`	Undocumented
Method	`visit_While`	Undocumented
Method	`visit_Yield`	Undocumented
Instance Variable	`cfg`	Undocumented
Instance Variable	`current_block`	Undocumented
Instance Variable	`current_id`	Undocumented
Instance Variable	`isShort`	Undocumented
Property	`loop_stack`	Undocumented
Property	`try_stack`	Undocumented
Instance Variable	`_callbuf`	Undocumented
Instance Variable	`_treebuf`	Undocumented

def __init__(self, short=True, treebuf=None): (source) ¶

Undocumented

Parameters
short:`bool`	Undocumented
treebuf:`DefaultDict[str, Deque]`	Undocumented

def add_exit(self, block, nextblock, exitcase=None): (source) ¶

Add a new exit to a block. Args: block: A block to which an exit must be added. nextblock: The block to which control jumps from the new exit. exitcase: An AST node representing the 'case' (or condition) leading to the exit from the block in the program.

Parameters
block:`Block`	Undocumented
nextblock:`Block`	Undocumented
exitcase:`Union[Compare, None, ast.BoolOp, ast.expr]`	Undocumented

def add_statement(self, block, statement): (source) ¶

Add a statement to a block. Args: block: A Block object to which a statement must be added. statement: An AST node representing the statement that must be added to the current block.

Parameters
block:`Block`	Undocumented
statement:`Union[stmt, Call]`	Undocumented

def build(self, name, tree, asynchr=False, entry_id=0): (source) ¶

Build a CFG from an AST. Args: name: The name of the CFG being built. tree: The root of the AST from which the CFG must be built. async: Boolean indicating whether the CFG being built represents an asynchronous function or not. When the CFG of a Python program is being built, it is considered like a synchronous 'main' function. entry_id: Value for the id of the entry block of the CFG. Returns: The CFG produced from the AST.

Parameters
name:`str`	Undocumented
tree:`Module`	Undocumented
asynchr:`bool`	Undocumented
entry_id:`int`	Undocumented
Returns
`CFG`	Undocumented

def build_from_file(self, name, filepath): (source) ¶

Build a CFG from some Python source file. Args: name: The name of the CFG being built. filepath: The path to the file containing the Python source code to build the CFG from. Returns: The CFG produced from the source file.

Parameters
name:`str`	Undocumented
filepath:`str`	Undocumented
Returns
`CFG`	Undocumented

def build_from_src(self, name, src): (source) ¶

Build a CFG from some Python source code. Args: name: The name of the CFG being built. src: A string containing the source code to build the CFG from. Returns: The CFG produced from the source code.

Parameters
name:`str`	Undocumented
src:`str`	Undocumented
Returns
`CFG`	Undocumented

def clean_cfg(self, block, visited): (source) ¶

Remove the useless (empty) blocks from a CFG. Args: block: The block from which to start traversing the CFG to clean it. visited: A list of blocks that already have been visited by clean_cfg (recursive function).

Parameters
block:`Block`	Undocumented
visited:`Set[Block]`	Undocumented

def new_block(self, statement=None): (source) ¶

Create a new block with a new id. Returns: A Block object with a new unique id.

Returns
`Block`	Undocumented

def new_classCFG(self, node, asynchr=False): (source) ¶

Create a new sub-CFG for a class definition and add it to the class CFGs of the CFG being built. Args: node: The AST node containing the class definition. async: Boolean indicating whether the class for which the CFG is being built is asynchronous or not.

Parameters
node:`ClassDef`	Undocumented
asynchr:`bool`	Undocumented

def new_func_block(self): (source) ¶

Create a new function block with a new id. Returns: A FuncBlock object with a new unique id.

Returns
`FuncBlock`	Undocumented

def new_functionCFG(self, node, asynchr=False): (source) ¶

Create a new sub-CFG for a function definition and add it to the function CFGs of the CFG being built. Args: node: The AST node containing the function definition. async: Boolean indicating whether the function for which the CFG is being built is asynchronous or not.

Parameters
node:`FunctionDef`	Undocumented
asynchr:`bool`	Undocumented

def new_loopguard(self): (source) ¶

Create a new block for a loop's guard if the current block is not empty. Links the current block to the new loop guard. Returns: The block to be used as new loop guard.

Returns
`Block`	Undocumented

def new_try_block(self, statement=None): (source) ¶

Undocumented

def visit_AnnAssign(self, node): (source) ¶

Undocumented

Parameters
node:`AnnAssign`	Undocumented

def visit_Assert(self, node): (source) ¶

Undocumented

def visit_Assign(self, node): (source) ¶

Undocumented

Parameters
node:`Assign`	Undocumented

def visit_AsyncFunctionDef(self, node): (source) ¶

Undocumented

def visit_AugAssign(self, node): (source) ¶

Undocumented

Parameters
node:`AugAssign`	Undocumented

def visit_Await(self, node): (source) ¶

Undocumented

def visit_Break(self, node): (source) ¶

Undocumented

Parameters
node:`Break`	Undocumented

def visit_Call(self, node): (source) ¶

Undocumented

Parameters
node:`Call`	Undocumented

def visit_ClassDef(self, node): (source) ¶

Undocumented

Parameters
node:`ClassDef`	Undocumented

def visit_Continue(self, node): (source) ¶

Undocumented

def visit_ExceptHandler(self, node): (source) ¶

Undocumented

Parameters
node:`ExceptHandler`	Undocumented

def visit_Expr(self, node): (source) ¶

Undocumented

Parameters
node:`Expr`	Undocumented

def visit_For(self, node): (source) ¶

Undocumented

Parameters
node:`For`	Undocumented

def visit_FunctionDef(self, node): (source) ¶

Undocumented

Parameters
node:`FunctionDef`	Undocumented

def visit_If(self, node): (source) ¶

Undocumented

Parameters
node:`If`	Undocumented

def visit_Import(self, node): (source) ¶

Undocumented

Parameters
node:`Import`	Undocumented

def visit_ImportFrom(self, node): (source) ¶

Undocumented

Parameters
node:`ImportFrom`	Undocumented

def visit_Raise(self, node): (source) ¶

Undocumented

def visit_Return(self, node): (source) ¶

Undocumented

Parameters
node:`Return`	Undocumented

def visit_Try(self, node): (source) ¶

Undocumented

Parameters
node:`Try`	Undocumented

def visit_While(self, node): (source) ¶

Undocumented

Parameters
node:`While`	Undocumented

def visit_Yield(self, node): (source) ¶

Undocumented

Parameters
node:`Yield`	Undocumented

cfg = (source) ¶

Undocumented

current_block = (source) ¶

Undocumented

current_id = (source) ¶

Undocumented

isShort = (source) ¶

Undocumented

@property
loop_stack = (source) ¶

Undocumented

@property
try_stack: Deque[TryStackObject] = (source) ¶

Undocumented

_callbuf: List[FuncBlock] = (source) ¶

Undocumented

_treebuf = (source) ¶

Undocumented