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| author | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
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diff --git a/share/doc/gdb/Symbols-In-Python.html b/share/doc/gdb/Symbols-In-Python.html new file mode 100644 index 0000000..05b924f --- /dev/null +++ b/share/doc/gdb/Symbols-In-Python.html @@ -0,0 +1,457 @@ +<!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: Symbols In Python</title> + +<meta name="description" content="Debugging with GDB: Symbols In Python"> +<meta name="keywords" content="Debugging with GDB: Symbols 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="Symbol-Tables-In-Python.html#Symbol-Tables-In-Python" rel="next" title="Symbol Tables In Python"> +<link href="Blocks-In-Python.html#Blocks-In-Python" rel="previous" title="Blocks 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="Symbols-In-Python"></a> +<div class="header"> +<p> +Next: <a href="Symbol-Tables-In-Python.html#Symbol-Tables-In-Python" accesskey="n" rel="next">Symbol Tables In Python</a>, Previous: <a href="Blocks-In-Python.html#Blocks-In-Python" accesskey="p" rel="previous">Blocks 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="Python-representation-of-Symbols"></a> +<h4 class="subsubsection">23.3.2.28 Python representation of Symbols</h4> + +<a name="index-symbols-in-python"></a> +<a name="index-gdb_002eSymbol"></a> + +<p><small>GDB</small> represents every variable, function and type as an +entry in a symbol table. See <a href="Symbols.html#Symbols">Examining the Symbol Table</a>. +Similarly, Python represents these symbols in <small>GDB</small> with the +<code>gdb.Symbol</code> object. +</p> +<p>The following symbol-related functions are available in the <code>gdb</code> +module: +</p> +<a name="index-gdb_002elookup_005fsymbol"></a> +<dl> +<dt><a name="index-gdb_002elookup_005fsymbol-1"></a>Function: <strong>gdb.lookup_symbol</strong> <em>(name <span class="roman">[</span>, block <span class="roman">[</span>, domain<span class="roman">]]</span>)</em></dt> +<dd><p>This function searches for a symbol by name. The search scope can be +restricted to the parameters defined in the optional domain and block +arguments. +</p> +<p><var>name</var> is the name of the symbol. It must be a string. The +optional <var>block</var> argument restricts the search to symbols visible +in that <var>block</var>. The <var>block</var> argument must be a +<code>gdb.Block</code> object. If omitted, the block for the current frame +is used. The optional <var>domain</var> argument restricts +the search to the domain type. The <var>domain</var> argument must be a +domain constant defined in the <code>gdb</code> module and described later +in this chapter. +</p> +<p>The result is a tuple of two elements. +The first element is a <code>gdb.Symbol</code> object or <code>None</code> if the symbol +is not found. +If the symbol is found, the second element is <code>True</code> if the symbol +is a field of a method’s object (e.g., <code>this</code> in C<tt>++</tt>), +otherwise it is <code>False</code>. +If the symbol is not found, the second element is <code>False</code>. +</p></dd></dl> + +<a name="index-gdb_002elookup_005fglobal_005fsymbol"></a> +<dl> +<dt><a name="index-gdb_002elookup_005fglobal_005fsymbol-1"></a>Function: <strong>gdb.lookup_global_symbol</strong> <em>(name <span class="roman">[</span>, domain<span class="roman">]</span>)</em></dt> +<dd><p>This function searches for a global symbol by name. +The search scope can be restricted to by the domain argument. +</p> +<p><var>name</var> is the name of the symbol. It must be a string. +The optional <var>domain</var> argument restricts the search to the domain type. +The <var>domain</var> argument must be a domain constant defined in the <code>gdb</code> +module and described later in this chapter. +</p> +<p>The result is a <code>gdb.Symbol</code> object or <code>None</code> if the symbol +is not found. +</p></dd></dl> + +<a name="index-gdb_002elookup_005fstatic_005fsymbol"></a> +<dl> +<dt><a name="index-gdb_002elookup_005fstatic_005fsymbol-1"></a>Function: <strong>gdb.lookup_static_symbol</strong> <em>(name <span class="roman">[</span>, domain<span class="roman">]</span>)</em></dt> +<dd><p>This function searches for a global symbol with static linkage by name. +The search scope can be restricted to by the domain argument. +</p> +<p><var>name</var> is the name of the symbol. It must be a string. +The optional <var>domain</var> argument restricts the search to the domain type. +The <var>domain</var> argument must be a domain constant defined in the <code>gdb</code> +module and described later in this chapter. +</p> +<p>The result is a <code>gdb.Symbol</code> object or <code>None</code> if the symbol +is not found. +</p> +<p>Note that this function will not find function-scoped static variables. To look +up such variables, iterate over the variables of the function’s +<code>gdb.Block</code> and check that <code>block.addr_class</code> is +<code>gdb.SYMBOL_LOC_STATIC</code>. +</p> +<p>There can be multiple global symbols with static linkage with the same +name. This function will only return the first matching symbol that +it finds. Which symbol is found depends on where <small>GDB</small> is +currently stopped, as <small>GDB</small> will first search for matching +symbols in the current object file, and then search all other object +files. If the application is not yet running then <small>GDB</small> will +search all object files in the order they appear in the debug +information. +</p></dd></dl> + +<a name="index-gdb_002elookup_005fstatic_005fsymbols"></a> +<dl> +<dt><a name="index-gdb_002elookup_005fstatic_005fsymbols-1"></a>Function: <strong>gdb.lookup_static_symbols</strong> <em>(name <span class="roman">[</span>, domain<span class="roman">]</span>)</em></dt> +<dd><p>Similar to <code>gdb.lookup_static_symbol</code>, this function searches for +global symbols with static linkage by name, and optionally restricted +by the domain argument. However, this function returns a list of all +matching symbols found, not just the first one. +</p> +<p><var>name</var> is the name of the symbol. It must be a string. +The optional <var>domain</var> argument restricts the search to the domain type. +The <var>domain</var> argument must be a domain constant defined in the <code>gdb</code> +module and described later in this chapter. +</p> +<p>The result is a list of <code>gdb.Symbol</code> objects which could be empty +if no matching symbols were found. +</p> +<p>Note that this function will not find function-scoped static variables. To look +up such variables, iterate over the variables of the function’s +<code>gdb.Block</code> and check that <code>block.addr_class</code> is +<code>gdb.SYMBOL_LOC_STATIC</code>. +</p></dd></dl> + +<p>A <code>gdb.Symbol</code> object has the following attributes: +</p> +<dl> +<dt><a name="index-Symbol_002etype"></a>Variable: <strong>Symbol.type</strong></dt> +<dd><p>The type of the symbol or <code>None</code> if no type is recorded. +This attribute is represented as a <code>gdb.Type</code> object. +See <a href="Types-In-Python.html#Types-In-Python">Types In Python</a>. This attribute is not writable. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002esymtab"></a>Variable: <strong>Symbol.symtab</strong></dt> +<dd><p>The symbol table in which the symbol appears. This attribute is +represented as a <code>gdb.Symtab</code> object. See <a href="Symbol-Tables-In-Python.html#Symbol-Tables-In-Python">Symbol Tables In Python</a>. This attribute is not writable. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002eline"></a>Variable: <strong>Symbol.line</strong></dt> +<dd><p>The line number in the source code at which the symbol was defined. +This is an integer. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002ename"></a>Variable: <strong>Symbol.name</strong></dt> +<dd><p>The name of the symbol as a string. This attribute is not writable. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002elinkage_005fname"></a>Variable: <strong>Symbol.linkage_name</strong></dt> +<dd><p>The name of the symbol, as used by the linker (i.e., may be mangled). +This attribute is not writable. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002eprint_005fname"></a>Variable: <strong>Symbol.print_name</strong></dt> +<dd><p>The name of the symbol in a form suitable for output. This is either +<code>name</code> or <code>linkage_name</code>, depending on whether the user +asked <small>GDB</small> to display demangled or mangled names. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002eaddr_005fclass"></a>Variable: <strong>Symbol.addr_class</strong></dt> +<dd><p>The address class of the symbol. This classifies how to find the value +of a symbol. Each address class is a constant defined in the +<code>gdb</code> module and described later in this chapter. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002eneeds_005fframe"></a>Variable: <strong>Symbol.needs_frame</strong></dt> +<dd><p>This is <code>True</code> if evaluating this symbol’s value requires a frame +(see <a href="Frames-In-Python.html#Frames-In-Python">Frames In Python</a>) and <code>False</code> otherwise. Typically, +local variables will require a frame, but other symbols will not. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002eis_005fargument"></a>Variable: <strong>Symbol.is_argument</strong></dt> +<dd><p><code>True</code> if the symbol is an argument of a function. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002eis_005fconstant"></a>Variable: <strong>Symbol.is_constant</strong></dt> +<dd><p><code>True</code> if the symbol is a constant. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002eis_005ffunction"></a>Variable: <strong>Symbol.is_function</strong></dt> +<dd><p><code>True</code> if the symbol is a function or a method. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002eis_005fvariable"></a>Variable: <strong>Symbol.is_variable</strong></dt> +<dd><p><code>True</code> if the symbol is a variable. +</p></dd></dl> + +<p>A <code>gdb.Symbol</code> object has the following methods: +</p> +<dl> +<dt><a name="index-Symbol_002eis_005fvalid"></a>Function: <strong>Symbol.is_valid</strong> <em>()</em></dt> +<dd><p>Returns <code>True</code> if the <code>gdb.Symbol</code> object is valid, +<code>False</code> if not. A <code>gdb.Symbol</code> object can become invalid if +the symbol it refers to does not exist in <small>GDB</small> any longer. +All other <code>gdb.Symbol</code> methods will throw an exception if it is +invalid at the time the method is called. +</p></dd></dl> + +<dl> +<dt><a name="index-Symbol_002evalue"></a>Function: <strong>Symbol.value</strong> <em>(<span class="roman">[</span>frame<span class="roman">]</span>)</em></dt> +<dd><p>Compute the value of the symbol, as a <code>gdb.Value</code>. For +functions, this computes the address of the function, cast to the +appropriate type. If the symbol requires a frame in order to compute +its value, then <var>frame</var> must be given. If <var>frame</var> is not +given, or if <var>frame</var> is invalid, then this method will throw an +exception. +</p></dd></dl> + +<p>The available domain categories in <code>gdb.Symbol</code> are represented +as constants in the <code>gdb</code> module: +</p> +<dl compact="compact"> +<dd><a name="index-SYMBOL_005fUNDEF_005fDOMAIN"></a> +</dd> +<dt><code>gdb.SYMBOL_UNDEF_DOMAIN</code> +<a name="index-gdb_002eSYMBOL_005fUNDEF_005fDOMAIN"></a> +</dt> +<dd><p>This is used when a domain has not been discovered or none of the +following domains apply. This usually indicates an error either +in the symbol information or in <small>GDB</small>’s handling of symbols. +</p> +<a name="index-SYMBOL_005fVAR_005fDOMAIN"></a> +</dd> +<dt><code>gdb.SYMBOL_VAR_DOMAIN</code> +<a name="index-gdb_002eSYMBOL_005fVAR_005fDOMAIN"></a> +</dt> +<dd><p>This domain contains variables, function names, typedef names and enum +type values. +</p> +<a name="index-SYMBOL_005fSTRUCT_005fDOMAIN"></a> +</dd> +<dt><code>gdb.SYMBOL_STRUCT_DOMAIN</code> +<a name="index-gdb_002eSYMBOL_005fSTRUCT_005fDOMAIN"></a> +</dt> +<dd><p>This domain holds struct, union and enum type names. +</p> +<a name="index-SYMBOL_005fLABEL_005fDOMAIN"></a> +</dd> +<dt><code>gdb.SYMBOL_LABEL_DOMAIN</code> +<a name="index-gdb_002eSYMBOL_005fLABEL_005fDOMAIN"></a> +</dt> +<dd><p>This domain contains names of labels (for gotos). +</p> +<a name="index-SYMBOL_005fMODULE_005fDOMAIN"></a> +</dd> +<dt><code>gdb.SYMBOL_MODULE_DOMAIN</code> +<a name="index-gdb_002eSYMBOL_005fMODULE_005fDOMAIN"></a> +</dt> +<dd><p>This domain contains names of Fortran module types. +</p> +<a name="index-SYMBOL_005fCOMMON_005fBLOCK_005fDOMAIN"></a> +</dd> +<dt><code>gdb.SYMBOL_COMMON_BLOCK_DOMAIN</code> +<a name="index-gdb_002eSYMBOL_005fCOMMON_005fBLOCK_005fDOMAIN"></a> +</dt> +<dd><p>This domain contains names of Fortran common blocks. +</p></dd> +</dl> + +<p>The available address class categories in <code>gdb.Symbol</code> are represented +as constants in the <code>gdb</code> module: +</p> +<dl compact="compact"> +<dd><a name="index-SYMBOL_005fLOC_005fUNDEF"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_UNDEF</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fUNDEF"></a> +</dt> +<dd><p>If this is returned by address class, it indicates an error either in +the symbol information or in <small>GDB</small>’s handling of symbols. +</p> +<a name="index-SYMBOL_005fLOC_005fCONST"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_CONST</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fCONST"></a> +</dt> +<dd><p>Value is constant int. +</p> +<a name="index-SYMBOL_005fLOC_005fSTATIC"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_STATIC</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fSTATIC"></a> +</dt> +<dd><p>Value is at a fixed address. +</p> +<a name="index-SYMBOL_005fLOC_005fREGISTER"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_REGISTER</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fREGISTER"></a> +</dt> +<dd><p>Value is in a register. +</p> +<a name="index-SYMBOL_005fLOC_005fARG"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_ARG</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fARG"></a> +</dt> +<dd><p>Value is an argument. This value is at the offset stored within the +symbol inside the frame’s argument list. +</p> +<a name="index-SYMBOL_005fLOC_005fREF_005fARG"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_REF_ARG</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fREF_005fARG"></a> +</dt> +<dd><p>Value address is stored in the frame’s argument list. Just like +<code>LOC_ARG</code> except that the value’s address is stored at the +offset, not the value itself. +</p> +<a name="index-SYMBOL_005fLOC_005fREGPARM_005fADDR"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_REGPARM_ADDR</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fREGPARM_005fADDR"></a> +</dt> +<dd><p>Value is a specified register. Just like <code>LOC_REGISTER</code> except +the register holds the address of the argument instead of the argument +itself. +</p> +<a name="index-SYMBOL_005fLOC_005fLOCAL"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_LOCAL</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fLOCAL"></a> +</dt> +<dd><p>Value is a local variable. +</p> +<a name="index-SYMBOL_005fLOC_005fTYPEDEF"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_TYPEDEF</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fTYPEDEF"></a> +</dt> +<dd><p>Value not used. Symbols in the domain <code>SYMBOL_STRUCT_DOMAIN</code> all +have this class. +</p> +<a name="index-SYMBOL_005fLOC_005fLABEL"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_LABEL</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fLABEL"></a> +</dt> +<dd><p>Value is a label. +</p> +<a name="index-SYMBOL_005fLOC_005fBLOCK"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_BLOCK</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fBLOCK"></a> +</dt> +<dd><p>Value is a block. +</p> +<a name="index-SYMBOL_005fLOC_005fCONST_005fBYTES"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_CONST_BYTES</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fCONST_005fBYTES"></a> +</dt> +<dd><p>Value is a byte-sequence. +</p> +<a name="index-SYMBOL_005fLOC_005fUNRESOLVED"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_UNRESOLVED</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fUNRESOLVED"></a> +</dt> +<dd><p>Value is at a fixed address, but the address of the variable has to be +determined from the minimal symbol table whenever the variable is +referenced. +</p> +<a name="index-SYMBOL_005fLOC_005fOPTIMIZED_005fOUT"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_OPTIMIZED_OUT</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fOPTIMIZED_005fOUT"></a> +</dt> +<dd><p>The value does not actually exist in the program. +</p> +<a name="index-SYMBOL_005fLOC_005fCOMPUTED"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_COMPUTED</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fCOMPUTED"></a> +</dt> +<dd><p>The value’s address is a computed location. +</p> +<a name="index-SYMBOL_005fLOC_005fCOMMON_005fBLOCK"></a> +</dd> +<dt><code>gdb.SYMBOL_LOC_COMMON_BLOCK</code> +<a name="index-gdb_002eSYMBOL_005fLOC_005fCOMMON_005fBLOCK"></a> +</dt> +<dd><p>The value’s address is a symbol. This is only used for Fortran common +blocks. +</p></dd> +</dl> + +<hr> +<div class="header"> +<p> +Next: <a href="Symbol-Tables-In-Python.html#Symbol-Tables-In-Python" accesskey="n" rel="next">Symbol Tables In Python</a>, Previous: <a href="Blocks-In-Python.html#Blocks-In-Python" accesskey="p" rel="previous">Blocks 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> |