path: root/gdb/TODO

	gdb bug list
	John Gilmore, gnu@cygnus.com

This bug list is probably not up to date or accurate, but it reflects
some known bugs in gdb, if you are into bug-hunting.


Update the TODO list with all the lists of gdb bugs lying around on paper.

"share" command should not need to be manually run.  It should be run
as soon as possible, automatically, both on "run" and on core files.

It should be possible to use symbols from shared libraries before we know
exactly where the libraries will be loaded.  E.g. "b perror" before running
the program.  This could maybe be done as an extension of the "breakpoint
re-evaluation" after new symbols are loaded.

Make single_step() insert and remove breakpoints in one operation.

Speed up single stepping by avoiding extraneous ptrace calls.

Speed up single stepping by not inserting and removing breakpoints
each time the inferior starts and stops.

Speed up watchpoints by not single-stepping them, but do something
faster like single-line execution.

Update gdb.texinfo to include doc on the directory structure and 
the various tricks of building gdb.

Do a tutorial in gdb.texinfo on how to do simple things in gdb.
E.g. how to set a breakpoint that just prints something and continues.
How to break on aborts.  Etc.

Do a "new features" section for release 4.

Provide "voodoo" debugging of core files.  This creates a zombie
process as a child of the debugger, and loads it up with the data,
stack, and regs of the core file.  This allows you to call functions
in the executable, to manipulate the data in the core file.

GDB reopens the source file on every line, as you "next" through it.

Referencing the vtbl member of a struct doesn't work.  It prints OK
if you print the struct, but it gets 0 if you try to deref it.

Persistent command history: A feature where you could save off a list
of the commands you did, so you can edit it into something that will bring
the target to the same place every time you source it.  Sun wants it.
This would also be useful for automated fast watchpointing; if you go
past the place where it watchpoints, you just start it over again and
do it more carefully.

Deal with the Sun ptrace bug that loses the registers if the stack is
paged out.

Finish the C++ exception handling stub routines.  Lint points them out
as unused statics functions.

"i source" only shows you info about files that it can read.  When it
can't read a file and complains, you can't see any info about it, like
where it was compiled.  Perhaps "i source" should take an argument
like that of "list".

See if coredep.c's fetch_core_registers can be used on more machines.
E.g. MIPS (mips-xdep.c).

coredep.c is completely broken.  Needs work just to compile, it uses
"u" and doesn't declare it, etc.

unpack_double() does not handle IEEE float on the target unless the host
is also IEEE.  Death on a vax.

Test cross-debugging Unix-to-Unix.

Check the RAPP remote protocol.  What is it?  It's in Makefile.dist
and one ChangeLog entry.

Set up interface between GDB and INFO so that you can hop into interactive
INFO and back out again.  When running under Emacs, should use Emacs
info, else fork the info program.  Installation of GDB should install
its texinfo files into the info tree automagically, including the readline
texinfo files..

Improve backtrace output to avoid line wraps.  Prettify it.

"help address" ought to find the "help set addressprint" entry.

Remove the VTBL internal guts from printouts of C++ structs, unless
vtblprint is set.

Remove "at 0xnnnn" from the "b foo" response, if !addressprint and if
it matches the source line indicated.

The prompt at end of screen should accept space as well as CR.

"List" should put you into a pseudo-"more" where you can hit space 
to get more, forever to eof.

Check STORE_RETURN_VALUE on all architectures.  Check near it in tm-sparc.h
for other bogosities.

Check for storage leaks in GDB, I'm sure there are a lot!

vtblprint of a vtbl should demangle the names it's printing.

Backtrace should point out what the currently selected frame is, in its
display, perhaps showing ">3 foo (bar, ...)" rather than "#3 foo (bar, ...)".

"i program" should work for core files, and display more info, like what
actually caused it to die.

Hitting ^Z to an inferior doesn't work right, it takes several continues
to make it actually go.

"i fun" doesn't show misc function vector symbols.

"x/10i" should shorten the long name, if any, on subsequent lines.

Check through the code for FIXME comments and fix them.  dbxread.c,
blockframe.c, and plenty more.

"next" over a function that longjumps, never stops until next time you happen
to get to that spot by accident.  E.g. "n" over execute_command which has
an error.

Watchpoints seem not entirely reliable.

"set zeroprint off", don't bother printing members of structs which are entirely
zero.  Useful for those big structs with few useful members.

GDB does four ioctl's for every command, probably switching terminal modes
to/from inferior or for readline or something.

terminal_ours versus terminal_inferior: cache state.  Switch should be a noop
if the state is the same, too.

ptype $i6 = void??!

Clean up invalid_float handling so gdb doesn't coredump when it tries to
access a NaN.  While this might work on SPARC, other machines are not
configured right.

"b value_at ; commands ; continue ; end" stops EVERY OTHER TIME!
Then once you enter a command, it does the command, runs two more
times, and then stops again!  Bizarre...  (This behaviour has been
modified, but it is not yet 100% predictable when e.g. the commands
call functions in the child, and while there, the child is interrupted
with a signal, or hits a breakpoint.)

Symbol completion with TAB does not unmangle names!

help completion, help history should work.

Symbol completion doesn't handle e.g. W::f.  (symtab.c,
make_symbol_completion_list).

AMD version: ^C should do ^Ak to stop ebmon.

Check that we can handle stack trace through varargs AND alloca in same
function, on 29K.

wait_for_inferior loops forever if wait() gives it an error.

"i frame" arg formatting sucks.  Should wrap lines.
"bt" arg formatting needs the same treatment .

"i frame" shows wrong "arglist at" location, doesn't show where the args
should be found, only their actual values.

Symbolic display of addrs, (& disassembly prefixes), don't show static
fns, e.g. enable_command in gdb.

'ptype yylval' ==> "union YYSTYPE { ..... }".  However, it is not a
union YYSTYPE, but is simply a YYSTYPE, which is a typedef for an
unnamed union.

"show all" should work.

There should be a way for "set" commands to validate the new setting
before it takes effect.

The "display" command should become the "always" command, e.g.
	"always print XXX"
	"always p/xxx XXX"
	"always echo foo"
	"always call XXX"
	"always x/i $pc", etc.

A mess of floating point opcodes are missing from sparc-opcode.h.
Also, a little program should test the table for bits that are
overspecified or underspecified.  E.g. if the must-be-ones bits
and the must-be-zeroes bits leave some fields unexamined, and the format
string leaves them unprinted, then point this out.  If multiple
non-alias patterns match, point this out too.  Finally, there should
be a sparc-optest.s file that tries each pattern out.  This file
should end up coming back the same (modulo transformation comments) 
if fed to "gas" then the .o is fed to gdb for disassembly.

Merge the xxx-opcode.h files with gas again...

Eliminate all the core_file_command's in all the xdep files.
Eliminate separate declarations of registers[] everywhere.

"ena d" is ambiguous, why?  "ena delete" seems to think it is a command!

Line numbers are off in some spots.  In proceed() at 1st "oneproc = 1",
it seems to run that statement, but it doesn't actually.

Perhaps the tdep and xdep files, and the tm and xm files, into a config
subdirectory.  If not, at least straighten out their names so that
they all start with the machine name.

inferior_status should include stop_print_frame.  It won't need to be
reset in wait_for_inferior after bpstat_stop_status call, then.

i line VAR produces "Line number not known for symbol ``var''.".  I
thought we were stashing that info now!

Make sure we can handle executables with no symbol info, e.g. /bin/csh.

We should be able to write to executables that aren't running.

We should be able to write to random files at hex offsets like adb.

Tiemann:  It is very painful to look at fp registers that hold
double precision values.  GDB is happy to show them to you as single
precision, but you cannot look at them as doubles.  Perhaps casting
should be changed to make this work; or maybe a new "set" option that
sets the default fp precision to single, double, or quad.  This is not
urgent, but would be nice to get into GDB 4.0.

Make "target xxx" command interruptible.

Handle add_file with separate text, data, and bss addresses.  Maybe
handle separate addresses for each segment in the object file?

Handle free_named_symtab to cope with multiply-loaded object files
in a dynamic linking environment.  Should remember the last copy loaded,
but not get too snowed if it finds references to the older copy.

Implement have_memory, have_stack, have_registers, have_execution.
Memory:  core, exec, child, vxworks even without child.
stack:   core, child, vxworks with child
registers:  core, child, vxworks with child
execution:  child, vxworks with child.

The original BFD core dump reading routine would itself coredump when fed
a garbage file as a core file.  Does the current one?

Breakpoints should not be inserted and deleted all the time.  Only the
one(s) there should be removed when we have to step over one.  Support
breakpoints that don't have to be removed to step over them.

Stop reading stop_registers!

Generalize and Standardize the RPC interface to a target program,
improve it beyond the "ptrace" interface, and see if it can become a standard
for remote debugging.  Is WRS interested in donating their target-end
code?

Remove all references to:
	text_offset
	data_offset
	text_data_start
	text_end
	exec_data_offset
	...
now that we have BFD.  All remaining are in machine dependent files.

When quitting with a running program, if a core file was previously
examined, you get "Couldn't read float regs from core file"...if 
indeed it can't.  generic_mourn_inferior...

...

Check signal argument to remote proceed's and error if set.

Handle floating point registers in core files under BFD.  Currently
they are punted.

Sort help and info output.

Re-organize help categories into things that tend to fit on a screen
and hang together.

When trying to print source lines but you can't find the file,
print the file name and line number, and leave it selected anyway
so "i source" will show it.

renote-nindy.c handles interrupts poorly; it error()s out of badly
chosen places, e.g. leaving current_frame zero, which causes core dumps
on the next command.

Add in commands like ADB's for searching for patterns, etc.  We should
be able to examine and patch raw unsymboled binaries as well in gdb as
we can in adb.  (E.g. increase the timeout in /bin/login without source).

Those xdep files that call register_addr without defining it are
probably simply broken.  When reconfiguring this part of gdb, I could
only make guesses about how to redo some of those files, and I
probably guessed wrong, or left them "for later" when I have a
machine that can attempt to build them.

Use the complain() mechanism for handling all the error() calls in dbxread.c,
and in similar situations in coffread.c and mipsread.c.

When doing "step" or "next", if a few lines of source are skipped between
the previous line and the current one, print those lines, not just the
last line of a multiline statement.

When searching for C++ superclasses in value_cast in valops.c, we must
not search the "fields", only the "superclasses".  There might be a
struct with a field name that matches the superclass name.  This can
happen when the struct was defined before the superclass (before the
name became a typedef).

Handling of "&" address-of operator needs some serious overhaul
for ANSI C and consistency on arrays and functions.
  For "float point[15];":
ptype &point[4]   ==> Attempt to take address of non-lvalue.
p     &point[4]   ==> Dereferences point[4] rather than giving you point+4.
  For "char *malloc();":
ptype malloc	  ==> "char *()";  should be same as
ptype &malloc     ==> "char *(*)()"
call printf ("%x\n", malloc)   ==> wierd value, should be same as
call printf ("%x\n", &malloc)  ==> correct value

Fix symbol reading in the presence of interrupts.  It currently leaves a
cleanup to blow away the entire symbol table when a QUIT occurs.