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diff --git a/share/doc/gdb/Blocks-In-Python.html b/share/doc/gdb/Blocks-In-Python.html new file mode 100644 index 0000000..0772feb --- /dev/null +++ b/share/doc/gdb/Blocks-In-Python.html @@ -0,0 +1,228 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1988-2023 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." --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>Debugging with GDB: Blocks In Python</title> + +<meta name="description" content="Debugging with GDB: Blocks In Python"> +<meta name="keywords" content="Debugging with GDB: Blocks In Python"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<link href="index.html#Top" rel="start" title="Top"> +<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Python-API.html#Python-API" rel="up" title="Python API"> +<link href="Symbols-In-Python.html#Symbols-In-Python" rel="next" title="Symbols In Python"> +<link href="Frames-In-Python.html#Frames-In-Python" rel="previous" title="Frames In Python"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +div.smalllisp {margin-left: 3.2em} +kbd {font-style:oblique} +pre.display {font-family: inherit} +pre.format {font-family: inherit} +pre.menu-comment {font-family: serif} +pre.menu-preformatted {font-family: serif} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +span.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Blocks-In-Python"></a> +<div class="header"> +<p> +Next: <a href="Symbols-In-Python.html#Symbols-In-Python" accesskey="n" rel="next">Symbols In Python</a>, Previous: <a href="Frames-In-Python.html#Frames-In-Python" accesskey="p" rel="previous">Frames In Python</a>, Up: <a href="Python-API.html#Python-API" accesskey="u" rel="up">Python API</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="Accessing-blocks-from-Python"></a> +<h4 class="subsubsection">23.3.2.27 Accessing blocks from Python</h4> + +<a name="index-blocks-in-python"></a> +<a name="index-gdb_002eBlock"></a> + +<p>In <small>GDB</small>, symbols are stored in blocks. A block corresponds +roughly to a scope in the source code. Blocks are organized +hierarchically, and are represented individually in Python as a +<code>gdb.Block</code>. Blocks rely on debugging information being +available. +</p> +<p>A frame has a block. Please see <a href="Frames-In-Python.html#Frames-In-Python">Frames In Python</a>, for a more +in-depth discussion of frames. +</p> +<p>The outermost block is known as the <em>global block</em>. The global +block typically holds public global variables and functions. +</p> +<p>The block nested just inside the global block is the <em>static +block</em>. The static block typically holds file-scoped variables and +functions. +</p> +<p><small>GDB</small> provides a method to get a block’s superblock, but there +is currently no way to examine the sub-blocks of a block, or to +iterate over all the blocks in a symbol table (see <a href="Symbol-Tables-In-Python.html#Symbol-Tables-In-Python">Symbol Tables In Python</a>). +</p> +<p>Here is a short example that should help explain blocks: +</p> +<div class="smallexample"> +<pre class="smallexample">/* This is in the global block. */ +int global; + +/* This is in the static block. */ +static int file_scope; + +/* 'function' is in the global block, and 'argument' is + in a block nested inside of 'function'. */ +int function (int argument) +{ + /* 'local' is in a block inside 'function'. It may or may + not be in the same block as 'argument'. */ + int local; + + { + /* 'inner' is in a block whose superblock is the one holding + 'local'. */ + int inner; + + /* If this call is expanded by the compiler, you may see + a nested block here whose function is 'inline_function' + and whose superblock is the one holding 'inner'. */ + inline_function (); + } +} +</pre></div> + +<p>A <code>gdb.Block</code> is iterable. The iterator returns the symbols +(see <a href="Symbols-In-Python.html#Symbols-In-Python">Symbols In Python</a>) local to the block. Python programs +should not assume that a specific block object will always contain a +given symbol, since changes in <small>GDB</small> features and +infrastructure may cause symbols move across blocks in a symbol +table. You can also use Python’s <em>dictionary syntax</em> to access +variables in this block, e.g.: +</p> +<div class="smallexample"> +<pre class="smallexample">symbol = some_block['variable'] # symbol is of type gdb.Symbol +</pre></div> + +<p>The following block-related functions are available in the <code>gdb</code> +module: +</p> +<a name="index-gdb_002eblock_005ffor_005fpc"></a> +<dl> +<dt><a name="index-gdb_002eblock_005ffor_005fpc-1"></a>Function: <strong>gdb.block_for_pc</strong> <em>(pc)</em></dt> +<dd><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>. This is identical to +<code>gdb.current_progspace().block_for_pc(pc)</code> and is included for +historical compatibility. +</p></dd></dl> + +<p>A <code>gdb.Block</code> object has the following methods: +</p> +<dl> +<dt><a name="index-Block_002eis_005fvalid"></a>Function: <strong>Block.is_valid</strong> <em>()</em></dt> +<dd><p>Returns <code>True</code> if the <code>gdb.Block</code> object is valid, +<code>False</code> if not. A block object can become invalid if the block it +refers to doesn’t exist anymore in the inferior. All other +<code>gdb.Block</code> methods will throw an exception if it is invalid at +the time the method is called. The block’s validity is also checked +during iteration over symbols of the block. +</p></dd></dl> + +<p>A <code>gdb.Block</code> object has the following attributes: +</p> +<dl> +<dt><a name="index-Block_002estart"></a>Variable: <strong>Block.start</strong></dt> +<dd><p>The start address of the block. This attribute is not writable. +</p></dd></dl> + +<dl> +<dt><a name="index-Block_002eend"></a>Variable: <strong>Block.end</strong></dt> +<dd><p>One past the last address that appears in the block. This attribute +is not writable. +</p></dd></dl> + +<dl> +<dt><a name="index-Block_002efunction"></a>Variable: <strong>Block.function</strong></dt> +<dd><p>The name of the block represented as a <code>gdb.Symbol</code>. If the +block is not named, then this attribute holds <code>None</code>. This +attribute is not writable. +</p> +<p>For ordinary function blocks, the superblock is the static block. +However, you should note that it is possible for a function block to +have a superblock that is not the static block – for instance this +happens for an inlined function. +</p></dd></dl> + +<dl> +<dt><a name="index-Block_002esuperblock"></a>Variable: <strong>Block.superblock</strong></dt> +<dd><p>The block containing this block. If this parent block does not exist, +this attribute holds <code>None</code>. This attribute is not writable. +</p></dd></dl> + +<dl> +<dt><a name="index-Block_002eglobal_005fblock"></a>Variable: <strong>Block.global_block</strong></dt> +<dd><p>The global block associated with this block. This attribute is not +writable. +</p></dd></dl> + +<dl> +<dt><a name="index-Block_002estatic_005fblock"></a>Variable: <strong>Block.static_block</strong></dt> +<dd><p>The static block associated with this block. This attribute is not +writable. +</p></dd></dl> + +<dl> +<dt><a name="index-Block_002eis_005fglobal"></a>Variable: <strong>Block.is_global</strong></dt> +<dd><p><code>True</code> if the <code>gdb.Block</code> object is a global block, +<code>False</code> if not. This attribute is not +writable. +</p></dd></dl> + +<dl> +<dt><a name="index-Block_002eis_005fstatic"></a>Variable: <strong>Block.is_static</strong></dt> +<dd><p><code>True</code> if the <code>gdb.Block</code> object is a static block, +<code>False</code> if not. This attribute is not writable. +</p></dd></dl> + +<hr> +<div class="header"> +<p> +Next: <a href="Symbols-In-Python.html#Symbols-In-Python" accesskey="n" rel="next">Symbols In Python</a>, Previous: <a href="Frames-In-Python.html#Frames-In-Python" accesskey="p" rel="previous">Frames In Python</a>, Up: <a href="Python-API.html#Python-API" accesskey="u" rel="up">Python API</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |