From ea3b06874c8a1037bad4fd5b9396d196e6963ac6 Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Sun, 23 Apr 2017 10:54:33 -0600 Subject: [PATCH] Rationalize "backtrace" command line parsing The backtrace command has peculiar command-line parsing. In particular, it splits the command line, then loops over the arguments. If it sees a word it recognizes, like "full", it effectively drops this word from the argument vector. Then, it pastes together the remaining arguments, passing them on to backtrace_command_1, which in turn passes the resulting string to parse_and_eval_long. The documentation doesn't mention the parse_and_eval_long at all, so it is a bit of a hidden feature that you can "bt 3*2". The strange algorithm above also means you can "bt 3 * no-filters 2" and get 6 frames... This patch changes backtrace's command line parsing to be a bit more rational. Now, special words like "full" are only recognized at the start of the command. This also updates the documentation to describe the various bt options individually. gdb/ChangeLog 2018-03-26 Tom Tromey * stack.c (backtrace_command): Rewrite command line parsing. gdb/doc/ChangeLog 2018-03-26 Tom Tromey * gdb.texinfo (Backtrace): Describe options individually. --- gdb/ChangeLog | 4 +++ gdb/doc/ChangeLog | 4 +++ gdb/doc/gdb.texinfo | 50 ++++++++++++++++++------------------ gdb/stack.c | 62 +++++++++++++++------------------------------ 4 files changed, 52 insertions(+), 68 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 47e6cff43da..532826c8716 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,7 @@ +2018-03-26 Tom Tromey + + * stack.c (backtrace_command): Rewrite command line parsing. + 2018-03-26 Simon Marchi * dwarf2read.c (DEF_VEC_I(offset_type)): Remove. diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog index 2441f154311..413e4560129 100644 --- a/gdb/doc/ChangeLog +++ b/gdb/doc/ChangeLog @@ -1,3 +1,7 @@ +2018-03-26 Tom Tromey + + * gdb.texinfo (Backtrace): Describe options individually. + 2018-03-19 Tom Tromey * observer.texi: Remove. diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 74e0fdb4a4d..28254c9e68c 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -7307,45 +7307,43 @@ frame (frame zero), followed by its caller (frame one), and on up the stack. @anchor{backtrace-command} -@table @code @kindex backtrace @kindex bt @r{(@code{backtrace})} -@item backtrace -@itemx bt -Print a backtrace of the entire stack: one line per frame for all -frames in the stack. +To print a backtrace of the entire stack, use the @code{backtrace} +command, or its alias @code{bt}. This command will print one line per +frame for frames in the stack. By default, all stack frames are +printed. You can stop the backtrace at any time by typing the system +interrupt character, normally @kbd{Ctrl-c}. -You can stop the backtrace at any time by typing the system interrupt -character, normally @kbd{Ctrl-c}. +@table @code +@item backtrace [@var{args}@dots{}] +@itemx bt [@var{args}@dots{}] +Print the backtrace of the entire stack. The optional @var{args} can +be one of the following: -@item backtrace @var{n} -@itemx bt @var{n} -Similar, but print only the innermost @var{n} frames. +@table @code +@item @var{n} +@itemx @var{n} +Print only the innermost @var{n} frames, where @var{n} is a positive +number. -@item backtrace -@var{n} -@itemx bt -@var{n} -Similar, but print only the outermost @var{n} frames. +@item -@var{n} +@itemx -@var{n} +Print only the outermost @var{n} frames, where @var{n} is a positive +number. -@item backtrace full -@itemx bt full -@itemx bt full @var{n} -@itemx bt full -@var{n} -Print the values of the local variables also. As described above, -@var{n} specifies the number of frames to print. +@item full +Print the values of the local variables also. This can be combined +with a number to limit the number of frames shown. -@item backtrace no-filters -@itemx bt no-filters -@itemx bt no-filters @var{n} -@itemx bt no-filters -@var{n} -@itemx bt no-filters full -@itemx bt no-filters full @var{n} -@itemx bt no-filters full -@var{n} +@item no-filters Do not run Python frame filters on this backtrace. @xref{Frame Filter API}, for more information. Additionally use @ref{disable frame-filter all} to turn off all frame filters. This is only relevant when @value{GDBN} has been configured with @code{Python} support. @end table +@end table @kindex where @kindex info stack diff --git a/gdb/stack.c b/gdb/stack.c index aad8fcd9873..13af6594a92 100644 --- a/gdb/stack.c +++ b/gdb/stack.c @@ -1850,61 +1850,39 @@ backtrace_command_1 (const char *count_exp, int show_locals, int no_filters, static void backtrace_command (const char *arg, int from_tty) { - int fulltrace_arg = -1, arglen = 0, argc = 0, no_filters = -1; - int user_arg = 0; + bool fulltrace = false; + bool filters = true; - std::string reconstructed_arg; if (arg) { - char **argv; - int i; + bool done = false; - gdb_argv built_argv (arg); - argv = built_argv.get (); - argc = 0; - for (i = 0; argv[i]; i++) + while (!done) { - unsigned int j; + const char *save_arg = arg; + std::string this_arg = extract_arg (&arg); - for (j = 0; j < strlen (argv[i]); j++) - argv[i][j] = TOLOWER (argv[i][j]); + if (this_arg.empty ()) + break; - if (no_filters < 0 && subset_compare (argv[i], "no-filters")) - no_filters = argc; + if (subset_compare (this_arg.c_str (), "no-filters")) + filters = false; + else if (subset_compare (this_arg.c_str (), "full")) + fulltrace = true; else { - if (fulltrace_arg < 0 && subset_compare (argv[i], "full")) - fulltrace_arg = argc; - else - { - user_arg++; - arglen += strlen (argv[i]); - } + /* Not a recognized argument, so stop. */ + arg = save_arg; + done = true; } - argc++; - } - arglen += user_arg; - if (fulltrace_arg >= 0 || no_filters >= 0) - { - if (arglen > 0) - { - for (i = 0; i < argc; i++) - { - if (i != fulltrace_arg && i != no_filters) - { - reconstructed_arg += argv[i]; - reconstructed_arg += " "; - } - } - arg = reconstructed_arg.c_str (); - } - else - arg = NULL; } + + if (*arg == '\0') + arg = NULL; } - backtrace_command_1 (arg, fulltrace_arg >= 0 /* show_locals */, - no_filters >= 0 /* no frame-filters */, from_tty); + backtrace_command_1 (arg, fulltrace /* show_locals */, + !filters /* no frame-filters */, from_tty); } /* Iterate over the local variables of a block B, calling CB with