-_dnl__ -*- Texinfo -*-
-_dnl__ Copyright (c) 1988 1989 1990 1991 Free Software Foundation, Inc.
-_dnl__ This file is part of the source for the GDB manual.
-@c M4 FRAGMENT: $Id$
-@node Source, Data, Stack, Top
-@chapter Examining Source Files
-
-_GDBN__ can print parts of your program's source, since the debugging
-information recorded in your program tells _GDBN__ what source files
-were used to built it. When your program stops, _GDBN__ spontaneously
-prints the line where it stopped. Likewise, when you select a stack
-frame (@pxref{Selection}), _GDBN__ prints the line where execution in
-that frame has stopped. You can print other portions of source files by
-explicit command.
-
-If you use _GDBN__ through its GNU Emacs interface, you may prefer to
-use Emacs facilities to view source; @pxref{Emacs}.
-
-@menu
-* List:: Printing Source Lines
-* Search:: Searching Source Files
-* Source Path:: Specifying Source Directories
-* Machine Code:: Source and Machine Code
-@end menu
-
-@node List, Search, Source, Source
-@section Printing Source Lines
-
-@kindex list
-@kindex l
-To print lines from a source file, use the @code{list} command
-(abbreviated @code{l}). There are several ways to specify what part
-of the file you want to print.
-
-Here are the forms of the @code{list} command most commonly used:
-
-@table @code
-@item list @var{linenum}
-Print ten lines centered around line number @var{linenum} in the
-current source file.
-
-@item list @var{function}
-Print ten lines centered around the beginning of function
-@var{function}.
-
-@item list
-Print ten more lines. If the last lines printed were printed with a
-@code{list} command, this prints ten lines following the last lines
-printed; however, if the last line printed was a solitary line printed
-as part of displaying a stack frame (@pxref{Stack}), this prints ten
-lines centered around that line.
-
-@item list -
-Print ten lines just before the lines last printed.
-@end table
-
-Repeating a @code{list} command with @key{RET} discards the argument,
-so it is equivalent to typing just @code{list}. This is more useful
-than listing the same lines again. An exception is made for an
-argument of @samp{-}; that argument is preserved in repetition so that
-each repetition moves up in the source file.
-
-@cindex linespec
-In general, the @code{list} command expects you to supply zero, one or two
-@dfn{linespecs}. Linespecs specify source lines; there are several ways
-of writing them but the effect is always to specify some source line.
-Here is a complete description of the possible arguments for @code{list}:
-
-@table @code
-@item list @var{linespec}
-Print ten lines centered around the line specified by @var{linespec}.
-
-@item list @var{first},@var{last}
-Print lines from @var{first} to @var{last}. Both arguments are
-linespecs.
-
-@item list ,@var{last}
-Print ten lines ending with @var{last}.
-
-@item list @var{first},
-Print ten lines starting with @var{first}.
-
-@item list +
-Print ten lines just after the lines last printed.
-
-@item list -
-Print ten lines just before the lines last printed.
-
-@item list
-As described in the preceding table.
-@end table
-
-Here are the ways of specifying a single source line---all the
-kinds of linespec.
-
-@table @code
-@item @var{number}
-Specifies line @var{number} of the current source file.
-When a @code{list} command has two linespecs, this refers to
-the same source file as the first linespec.
-
-@item +@var{offset}
-Specifies the line @var{offset} lines after the last line printed.
-When used as the second linespec in a @code{list} command that has
-two, this specifies the line @var{offset} lines down from the
-first linespec.
-
-@item -@var{offset}
-Specifies the line @var{offset} lines before the last line printed.
-
-@item @var{filename}:@var{number}
-Specifies line @var{number} in the source file @var{filename}.
-
-@item @var{function}
-@c FIXME: "of the open-brace" is C-centric. When we add other langs...
-Specifies the line of the open-brace that begins the body of the
-function @var{function}.
-
-@item @var{filename}:@var{function}
-Specifies the line of the open-brace that begins the body of the
-function @var{function} in the file @var{filename}. You only need the
-file name with a function name to avoid ambiguity when there are
-identically named functions in different source files.
-
-@item *@var{address}
-Specifies the line containing the program address @var{address}.
-@var{address} may be any expression.
-@end table
-
-@node Search, Source Path, List, Source
-@section Searching Source Files
-@cindex searching
-@kindex reverse-search
-
-There are two commands for searching through the current source file for a
-regular expression.
-
-@table @code
-@item forward-search @var{regexp}
-@itemx search @var{regexp}
-@kindex search
-@kindex forward-search
-The command @samp{forward-search @var{regexp}} checks each line, starting
-with the one following the last line listed, for a match for @var{regexp}.
-It lists the line that is found. You can abbreviate the command name
-as @code{fo}. The synonym @samp{search @var{regexp}} is also supported.
-
-@item reverse-search @var{regexp}
-The command @samp{reverse-search @var{regexp}} checks each line, starting
-with the one before the last line listed and going backward, for a match
-for @var{regexp}. It lists the line that is found. You can abbreviate
-this command as @code{rev}.
-@end table
-
-@node Source Path, Machine Code, Search, Source
-@section Specifying Source Directories
-
-@cindex source path
-@cindex directories for source files
-Executable programs sometimes do not record the directories of the source
-files from which they were compiled, just the names. Even when they do,
-the directories could be moved between the compilation and your debugging
-session. _GDBN__ has a list of directories to search for source files;
-this is called the @dfn{source path}. Each time _GDBN__ wants a source file,
-it tries all the directories in the list, in the order they are present
-in the list, until it finds a file with the desired name. Note that
-the executable search path is @emph{not} used for this purpose. Neither is
-the current working directory, unless it happens to be in the source
-path.
-
-If _GDBN__ can't find a source file in the source path, and the object
-program records a directory, _GDBN__ tries that directory too. If the
-source path is empty, and there is no record of the compilation
-directory, _GDBN__ will, as a last resort, look in the current
-directory.
-
-Whenever you reset or rearrange the source path, _GDBN__ will clear out
-any information it has cached about where source files are found, where
-each line is in the file, etc.
-
-@kindex directory
-When you start _GDBN__, its source path is empty.
-To add other directories, use the @code{directory} command.
-
-@table @code
-@item directory @var{dirname} @dots{}
-Add directory @var{dirname} to the front of the source path. Several
-directory names may be given to this command, separated by @samp{:} or
-whitespace. You may specify a directory that is already in the source
-path; this moves it forward, so it will be searched sooner. You can use
-the string @samp{$cdir} to refer to the compilation directory (if one is
-recorded), and @samp{$cwd} to refer to the current working directory.
-@footnote{@samp{$cwd} is not the same as @samp{.}---the former tracks
-the current working directory as it changes during your _GDBN__ session,
-while the latter is immediately expanded to the current directory at the
-time you add an entry to the source path.}
-
-@item directory
-Reset the source path to empty again. This requires confirmation.
-
-@c RET-repeat for @code{directory} is explicitly disabled, but since
-@c repeating it would be a no-op we don't say that. (thanks to RMS)
-
-@item show directories
-@kindex show directories
-Print the source path: show which directories it contains.
-@end table
-
-If your source path is cluttered with directories that are no longer of
-interest, _GDBN__ may sometimes cause confusion by finding the wrong
-versions of source. You can correct the situation as follows:
-
-@enumerate
-@item
-Use @code{directory} with no argument to reset the source path to empty.
-
-@item
-Use @code{directory} with suitable arguments to reinstall the
-directories you want in the source path. You can add all the
-directories in one command.
-@end enumerate
-
-@node Machine Code, , Source Path, Source
-@section Source and Machine Code
-You can use the command @code{info line} to map source lines to program
-addresses (and viceversa), and the command @code{disassemble} to display
-a range of addresses as machine instructions.
-
-@table @code
-@item info line @var{linespec}
-@kindex info line
-Print the starting and ending addresses of the compiled code for
-source line @var{linespec}. You can specify source lines in any of the
-ways understood by the @code{list} command (@pxref{List}).
-@end table
-
-For example, we can use @code{info line} to inquire on where the object
-code for the first line of function @code{m4_changequote} lies:
-@smallexample
-(_GDBP__) info line m4_changecom
-Line 895 of "builtin.c" starts at pc 0x634c and ends at 0x6350.
-@end smallexample
-
-@noindent
-We can also inquire (using @code{*@var{addr}} as the form for
-@var{linespec}) what source line covers a particular address:
-@smallexample
-(_GDBP__) info line *0x63ff
-Line 926 of "builtin.c" starts at pc 0x63e4 and ends at 0x6404.
-@end smallexample
-
-@kindex $_
-After @code{info line}, the default address for the @code{x}
-command is changed to the starting address of the line, so that
-@samp{x/i} is sufficient to begin examining the machine code
-(@pxref{Memory}). Also, this address is saved as the value of the
-convenience variable @code{$_} (@pxref{Convenience Vars}).
-
-@table @code
-@kindex disassemble
-@item disassemble
-This specialized command is provided to dump a range of memory as
-machine instructions. The default memory range is the function
-surrounding the program counter of the selected frame. A single
-argument to this command is a program counter value; the function
-surrounding this value will be dumped. Two arguments (separated by one
-or more spaces) specify a range of addresses (first inclusive, second
-exclusive) to be dumped.
-@end table
-
-We can use @code{disassemble} to inspect the object code
-range shown in the last @code{info line} example:
-
-@smallexample
-(_GDBP__) disas 0x63e4 0x6404
-Dump of assembler code from 0x63e4 to 0x6404:
-0x63e4 <builtin_init+5340>: ble 0x63f8 <builtin_init+5360>
-0x63e8 <builtin_init+5344>: sethi %hi(0x4c00), %o0
-0x63ec <builtin_init+5348>: ld [%i1+4], %o0
-0x63f0 <builtin_init+5352>: b 0x63fc <builtin_init+5364>
-0x63f4 <builtin_init+5356>: ld [%o0+4], %o0
-0x63f8 <builtin_init+5360>: or %o0, 0x1a4, %o0
-0x63fc <builtin_init+5364>: call 0x9288 <path_search>
-0x6400 <builtin_init+5368>: nop
-End of assembler dump.
-(_GDBP__)
-
-@end smallexample
projects / thirdparty / binutils-gdb.git / blobdiff