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Diffstat (limited to 'share/gdb/python/gdb/FrameDecorator.py')
-rw-r--r-- | share/gdb/python/gdb/FrameDecorator.py | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/share/gdb/python/gdb/FrameDecorator.py b/share/gdb/python/gdb/FrameDecorator.py new file mode 100644 index 0000000..1bbc5ab --- /dev/null +++ b/share/gdb/python/gdb/FrameDecorator.py @@ -0,0 +1,302 @@ +# Copyright (C) 2013-2014 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +import gdb + +# This small code snippet deals with problem of strings in Python 2.x +# and Python 3.x. Python 2.x has str and unicode classes which are +# sub-classes of basestring. In Python 3.x all strings are encoded +# and basestring has been removed. +try: + basestring +except NameError: + basestring = str + +class FrameDecorator(object): + """Basic implementation of a Frame Decorator""" + + """ This base frame decorator decorates a frame or another frame + decorator, and provides convenience methods. If this object is + wrapping a frame decorator, defer to that wrapped object's method + if it has one. This allows for frame decorators that have + sub-classed FrameDecorator object, but also wrap other frame + decorators on the same frame to correctly execute. + + E.g + + If the result of frame filters running means we have one gdb.Frame + wrapped by multiple frame decorators, all sub-classed from + FrameDecorator, the resulting hierarchy will be: + + Decorator1 + -- (wraps) Decorator2 + -- (wraps) FrameDecorator + -- (wraps) gdb.Frame + + In this case we have two frame decorators, both of which are + sub-classed from FrameDecorator. If Decorator1 just overrides the + 'function' method, then all of the other methods are carried out + by the super-class FrameDecorator. But Decorator2 may have + overriden other methods, so FrameDecorator will look at the + 'base' parameter and defer to that class's methods. And so on, + down the chain.""" + + # 'base' can refer to a gdb.Frame or another frame decorator. In + # the latter case, the child class will have called the super + # method and _base will be an object conforming to the Frame Filter + # class. + def __init__(self, base): + self._base = base + + @staticmethod + def _is_limited_frame(frame): + """Internal utility to determine if the frame is special or + limited.""" + sal = frame.find_sal() + + if (not sal.symtab or not sal.symtab.filename + or frame.type() == gdb.DUMMY_FRAME + or frame.type() == gdb.SIGTRAMP_FRAME): + + return True + + return False + + def elided(self): + """Return any elided frames that this class might be + wrapping, or None.""" + if hasattr(self._base, "elided"): + return self._base.elided() + + return None + + def function(self): + """ Return the name of the frame's function or an address of + the function of the frame. First determine if this is a + special frame. If not, try to determine filename from GDB's + frame internal function API. Finally, if a name cannot be + determined return the address. If this function returns an + address, GDB will attempt to determine the function name from + its internal minimal symbols store (for example, for inferiors + without debug-info).""" + + # Both gdb.Frame, and FrameDecorator have a method called + # "function", so determine which object this is. + if not isinstance(self._base, gdb.Frame): + if hasattr(self._base, "function"): + # If it is not a gdb.Frame, and there is already a + # "function" method, use that. + return self._base.function() + + frame = self.inferior_frame() + + if frame.type() == gdb.DUMMY_FRAME: + return "<function called from gdb>" + elif frame.type() == gdb.SIGTRAMP_FRAME: + return "<signal handler called>" + + func = frame.function() + + # If we cannot determine the function name, return the + # address. If GDB detects an integer value from this function + # it will attempt to find the function name from minimal + # symbols via its own internal functions. + if func == None: + pc = frame.pc() + return pc + + return str(func) + + def address(self): + """ Return the address of the frame's pc""" + + if hasattr(self._base, "address"): + return self._base.address() + + frame = self.inferior_frame() + return frame.pc() + + def filename(self): + """ Return the filename associated with this frame, detecting + and returning the appropriate library name is this is a shared + library.""" + + if hasattr(self._base, "filename"): + return self._base.filename() + + frame = self.inferior_frame() + sal = frame.find_sal() + if not sal.symtab or not sal.symtab.filename: + pc = frame.pc() + return gdb.solib_name(pc) + else: + return sal.symtab.filename + + def frame_args(self): + """ Return an iterable of frame arguments for this frame, if + any. The iterable object contains objects conforming with the + Symbol/Value interface. If there are no frame arguments, or + if this frame is deemed to be a special case, return None.""" + + if hasattr(self._base, "frame_args"): + return self._base.frame_args() + + frame = self.inferior_frame() + if self._is_limited_frame(frame): + return None + + args = FrameVars(frame) + return args.fetch_frame_args() + + def frame_locals(self): + """ Return an iterable of local variables for this frame, if + any. The iterable object contains objects conforming with the + Symbol/Value interface. If there are no frame locals, or if + this frame is deemed to be a special case, return None.""" + + if hasattr(self._base, "frame_locals"): + return self._base.frame_locals() + + frame = self.inferior_frame() + if self._is_limited_frame(frame): + return None + + args = FrameVars(frame) + return args.fetch_frame_locals() + + def line(self): + """ Return line number information associated with the frame's + pc. If symbol table/line information does not exist, or if + this frame is deemed to be a special case, return None""" + + if hasattr(self._base, "line"): + return self._base.line() + + frame = self.inferior_frame() + if self._is_limited_frame(frame): + return None + + sal = frame.find_sal() + if (sal): + return sal.line + else: + return None + + def inferior_frame(self): + """ Return the gdb.Frame underpinning this frame decorator.""" + + # If 'base' is a frame decorator, we want to call its inferior + # frame method. If '_base' is a gdb.Frame, just return that. + if hasattr(self._base, "inferior_frame"): + return self._base.inferior_frame() + return self._base + +class SymValueWrapper(object): + """A container class conforming to the Symbol/Value interface + which holds frame locals or frame arguments.""" + def __init__(self, symbol, value): + self.sym = symbol + self.val = value + + def value(self): + """ Return the value associated with this symbol, or None""" + return self.val + + def symbol(self): + """ Return the symbol, or Python text, associated with this + symbol, or None""" + return self.sym + +class FrameVars(object): + + """Utility class to fetch and store frame local variables, or + frame arguments.""" + + def __init__(self, frame): + self.frame = frame + self.symbol_class = { + gdb.SYMBOL_LOC_STATIC: True, + gdb.SYMBOL_LOC_REGISTER: True, + gdb.SYMBOL_LOC_ARG: True, + gdb.SYMBOL_LOC_REF_ARG: True, + gdb.SYMBOL_LOC_LOCAL: True, + gdb.SYMBOL_LOC_REGPARM_ADDR: True, + gdb.SYMBOL_LOC_COMPUTED: True + } + + def fetch_b(self, sym): + """ Local utility method to determine if according to Symbol + type whether it should be included in the iterator. Not all + symbols are fetched, and only symbols that return + True from this method should be fetched.""" + + # SYM may be a string instead of a symbol in the case of + # synthetic local arguments or locals. If that is the case, + # always fetch. + if isinstance(sym, basestring): + return True + + sym_type = sym.addr_class + + return self.symbol_class.get(sym_type, False) + + def fetch_frame_locals(self): + """Public utility method to fetch frame local variables for + the stored frame. Frame arguments are not fetched. If there + are no frame local variables, return an empty list.""" + lvars = [] + + try: + block = self.frame.block() + except RuntimeError: + block = None + + while block != None: + if block.is_global or block.is_static: + break + for sym in block: + if sym.is_argument: + continue; + if self.fetch_b(sym): + lvars.append(SymValueWrapper(sym, None)) + + block = block.superblock + + return lvars + + def fetch_frame_args(self): + """Public utility method to fetch frame arguments for the + stored frame. Frame arguments are the only type fetched. If + there are no frame argument variables, return an empty list.""" + + args = [] + + try: + block = self.frame.block() + except RuntimeError: + block = None + + while block != None: + if block.function != None: + break + block = block.superblock + + if block != None: + for sym in block: + if not sym.is_argument: + continue; + args.append(SymValueWrapper(sym, None)) + + return args |