toolchain/share/doc/gdb/Progspaces-In-Python.html

201 lines
9.6 KiB
HTML

<html lang="en">
<head>
<title>Progspaces In Python - Debugging with GDB</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="Debugging with GDB">
<meta name="generator" content="makeinfo 4.13">
<link title="Top" rel="start" href="index.html#Top">
<link rel="up" href="Python-API.html#Python-API" title="Python API">
<link rel="prev" href="Functions-In-Python.html#Functions-In-Python" title="Functions In Python">
<link rel="next" href="Objfiles-In-Python.html#Objfiles-In-Python" title="Objfiles In Python">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<!--
Copyright (C) 1988-2019 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``Free Software'' and ``Free Software Needs
Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,''
and with the Back-Cover Texts as in (a) below.
(a) The FSF's Back-Cover Text is: ``You are free to copy and modify
this GNU Manual. Buying copies from GNU Press supports the FSF in
developing GNU and promoting software freedom.''
-->
<meta http-equiv="Content-Style-Type" content="text/css">
<style type="text/css"><!--
pre.display { font-family:inherit }
pre.format { font-family:inherit }
pre.smalldisplay { font-family:inherit; font-size:smaller }
pre.smallformat { font-family:inherit; font-size:smaller }
pre.smallexample { font-size:smaller }
pre.smalllisp { font-size:smaller }
span.sc { font-variant:small-caps }
span.roman { font-family:serif; font-weight:normal; }
span.sansserif { font-family:sans-serif; font-weight:normal; }
--></style>
</head>
<body>
<div class="node">
<a name="Progspaces-In-Python"></a>
<p>
Next:&nbsp;<a rel="next" accesskey="n" href="Objfiles-In-Python.html#Objfiles-In-Python">Objfiles In Python</a>,
Previous:&nbsp;<a rel="previous" accesskey="p" href="Functions-In-Python.html#Functions-In-Python">Functions In Python</a>,
Up:&nbsp;<a rel="up" accesskey="u" href="Python-API.html#Python-API">Python API</a>
<hr>
</div>
<h5 class="subsubsection">23.2.2.23 Program Spaces In Python</h5>
<p><a name="index-progspaces-in-python-2224"></a><a name="index-gdb_002eProgspace-2225"></a><a name="index-Progspace-2226"></a>A program space, or <dfn>progspace</dfn>, represents a symbolic view
of an address space.
It consists of all of the objfiles of the program.
See <a href="Objfiles-In-Python.html#Objfiles-In-Python">Objfiles In Python</a>.
See <a href="Inferiors-and-Programs.html#Inferiors-and-Programs">program spaces</a>, for more details
about program spaces.
<p>The following progspace-related functions are available in the
<code>gdb</code> module:
<p><a name="index-gdb_002ecurrent_005fprogspace-2227"></a>
<div class="defun">
&mdash; Function: <b>gdb.current_progspace</b> ()<var><a name="index-gdb_002ecurrent_005fprogspace-2228"></a></var><br>
<blockquote><p>This function returns the program space of the currently selected inferior.
See <a href="Inferiors-and-Programs.html#Inferiors-and-Programs">Inferiors and Programs</a>. This is identical to
<code>gdb.selected_inferior().progspace</code> (see <a href="Inferiors-In-Python.html#Inferiors-In-Python">Inferiors In Python</a>) and is
included for historical compatibility.
</p></blockquote></div>
<p><a name="index-gdb_002eprogspaces-2229"></a>
<div class="defun">
&mdash; Function: <b>gdb.progspaces</b> ()<var><a name="index-gdb_002eprogspaces-2230"></a></var><br>
<blockquote><p>Return a sequence of all the progspaces currently known to <span class="sc">gdb</span>.
</p></blockquote></div>
<p>Each progspace is represented by an instance of the <code>gdb.Progspace</code>
class.
<div class="defun">
&mdash; Variable: <b>Progspace.filename</b><var><a name="index-Progspace_002efilename-2231"></a></var><br>
<blockquote><p>The file name of the progspace as a string.
</p></blockquote></div>
<div class="defun">
&mdash; Variable: <b>Progspace.pretty_printers</b><var><a name="index-Progspace_002epretty_005fprinters-2232"></a></var><br>
<blockquote><p>The <code>pretty_printers</code> attribute is a list of functions. It is
used to look up pretty-printers. A <code>Value</code> is passed to each
function in order; if the function returns <code>None</code>, then the
search continues. Otherwise, the return value should be an object
which is used to format the value. See <a href="Pretty-Printing-API.html#Pretty-Printing-API">Pretty Printing API</a>, for more
information.
</p></blockquote></div>
<div class="defun">
&mdash; Variable: <b>Progspace.type_printers</b><var><a name="index-Progspace_002etype_005fprinters-2233"></a></var><br>
<blockquote><p>The <code>type_printers</code> attribute is a list of type printer objects.
See <a href="Type-Printing-API.html#Type-Printing-API">Type Printing API</a>, for more information.
</p></blockquote></div>
<div class="defun">
&mdash; Variable: <b>Progspace.frame_filters</b><var><a name="index-Progspace_002eframe_005ffilters-2234"></a></var><br>
<blockquote><p>The <code>frame_filters</code> attribute is a dictionary of frame filter
objects. See <a href="Frame-Filter-API.html#Frame-Filter-API">Frame Filter API</a>, for more information.
</p></blockquote></div>
<p>A program space has the following methods:
<p><a name="index-Progspace_002eblock_005ffor_005fpc-2235"></a>
<div class="defun">
&mdash; Function: <b>Progspace.block_for_pc</b> (<var>pc</var>)<var><a name="index-Progspace_002eblock_005ffor_005fpc-2236"></a></var><br>
<blockquote><p>Return the innermost <code>gdb.Block</code> containing the given <var>pc</var>
value. If the block cannot be found for the <var>pc</var> value specified,
the function will return <code>None</code>.
</p></blockquote></div>
<p><a name="index-Progspace_002efind_005fpc_005fline-2237"></a>
<div class="defun">
&mdash; Function: <b>Progspace.find_pc_line</b> (<var>pc</var>)<var><a name="index-Progspace_002efind_005fpc_005fline-2238"></a></var><br>
<blockquote><p>Return the <code>gdb.Symtab_and_line</code> object corresponding to the
<var>pc</var> value. See <a href="Symbol-Tables-In-Python.html#Symbol-Tables-In-Python">Symbol Tables In Python</a>. If an invalid value
of <var>pc</var> is passed as an argument, then the <code>symtab</code> and
<code>line</code> attributes of the returned <code>gdb.Symtab_and_line</code>
object will be <code>None</code> and 0 respectively.
</p></blockquote></div>
<p><a name="index-Progspace_002eis_005fvalid-2239"></a>
<div class="defun">
&mdash; Function: <b>Progspace.is_valid</b> ()<var><a name="index-Progspace_002eis_005fvalid-2240"></a></var><br>
<blockquote><p>Returns <code>True</code> if the <code>gdb.Progspace</code> object is valid,
<code>False</code> if not. A <code>gdb.Progspace</code> object can become invalid
if the program space file it refers to is not referenced by any
inferior. All other <code>gdb.Progspace</code> methods will throw an
exception if it is invalid at the time the method is called.
</p></blockquote></div>
<p><a name="index-Progspace_002eobjfiles-2241"></a>
<div class="defun">
&mdash; Function: <b>Progspace.objfiles</b> ()<var><a name="index-Progspace_002eobjfiles-2242"></a></var><br>
<blockquote><p>Return a sequence of all the objfiles referenced by this program
space. See <a href="Objfiles-In-Python.html#Objfiles-In-Python">Objfiles In Python</a>.
</p></blockquote></div>
<p><a name="index-Progspace_002esolib_005fname-2243"></a>
<div class="defun">
&mdash; Function: <b>Progspace.solib_name</b> (<var>address</var>)<var><a name="index-Progspace_002esolib_005fname-2244"></a></var><br>
<blockquote><p>Return the name of the shared library holding the given <var>address</var>
as a string, or <code>None</code>.
</p></blockquote></div>
<p>One may add arbitrary attributes to <code>gdb.Progspace</code> objects
in the usual Python way.
This is useful if, for example, one needs to do some extra record keeping
associated with the program space.
<p>In this contrived example, we want to perform some processing when
an objfile with a certain symbol is loaded, but we only want to do
this once because it is expensive. To achieve this we record the results
with the program space because we can't predict when the desired objfile
will be loaded.
<pre class="smallexample"> (gdb) python
def clear_objfiles_handler(event):
event.progspace.expensive_computation = None
def expensive(symbol):
"""A mock routine to perform an "expensive" computation on symbol."""
print "Computing the answer to the ultimate question ..."
return 42
def new_objfile_handler(event):
objfile = event.new_objfile
progspace = objfile.progspace
if not hasattr(progspace, 'expensive_computation') or \
progspace.expensive_computation is None:
# We use 'main' for the symbol to keep the example simple.
# Note: There's no current way to constrain the lookup
# to one objfile.
symbol = gdb.lookup_global_symbol('main')
if symbol is not None:
progspace.expensive_computation = expensive(symbol)
gdb.events.clear_objfiles.connect(clear_objfiles_handler)
gdb.events.new_objfile.connect(new_objfile_handler)
end
(gdb) file /tmp/hello
Reading symbols from /tmp/hello...done.
Computing the answer to the ultimate question ...
(gdb) python print gdb.current_progspace().expensive_computation
42
(gdb) run
Starting program: /tmp/hello
Hello.
[Inferior 1 (process 4242) exited normally]
</pre>
</body></html>