We previously specified a few known register groups for the 'tui reg'
command. Other register groups could be accessed, but only by using the
'tui reg next' command and cycling through all the groups.
This commit removes the hard coded sub-commands of 'tui reg' and instead
adds dynamic completion of sub-commands based on the architecturally
defined register groups, giving immediate access to all available
register groups.
There is still the 'next' and 'prev' commands for cycling through the
register groups if that's wanted.
The new code maintains the ability to only enter partial names for
register groups, which is something we got for free when using the
standard sub-command mechanism.
The register (and register group) completer has been changed to use
get_current_arch rather than using the architecture of the currently
selected frame. When the target is running, this is equivalent,
however, when the target is not running, using get_current_arch will
provide results from the default architecture.
gdb/ChangeLog:
* completer.c: Add arch-utils.h include.
(enum reg_completer_targets): New enum.
(reg_or_group_completer_1): New function containing old
reg_or_group_completer, add and use new parameter to control what
is completed on. Use get_current_arch rather than architecture of
currently selected frame.
(reg_or_group_completer): Call new reg_or_group_completer_1.
(reggroup_completer): Call new reg_or_group_completer_1.
* completer.h (reggroup_completer): Add declaration.
* tui/tui-regs.c: Add 'completer.h' include.
(tui_reg_next_command): Renamed to...
(tui_reg_next): ...this. Adjust parameters and return rather than
display new group.
(tui_reg_prev_command): Renamed to...
(tui_reg_prev): ...this. Adjust parameters and return rather than
display new group.
(tui_reg_float_command): Delete.
(tui_reg_general_command): Delete.
(tui_reg_system_command): Delete.
(tui_reg_command): Rewrite to perform switching of register group.
Add header comment.
(tuireglist): Remove.
(tui_reggroup_completer): New function.
(_initialize_tui_regs): Remove 'tui reg' sub-commands, update
creation of 'tui reg' command.
* NEWS: Add comment about 'tui reg' changes.
gdb/doc/ChangeLog:
* gdb.texinfo (TUI Commands): Bring all 'tui reg' commands into a
single table entry.
Add new commands to specifically enable and disable tui mode. This is
in addition to the readline bindings, but might be easier for a user to
discover if they accidentally end up in tui mode.
gdb/ChangeLog:
* NEWS: Mention 'tui enable' and 'tui disable'.
* tui/tui.c (tui_enable_command): New function.
(tui_disable_command): New function.
(_initialize_tui): New function.
gdb/doc/ChangeLog:
* gdb.texinfo (TUI): Include 'tui enable' in the introduction.
(TUI Commands): Add 'tui enable' and 'tui disable' details.
Use cleanup to avoid leaking memory if an error occurs during tui
start up.
gdb/ChangeLog:
* tui/tui-layout.c (tui_set_layout_for_display_command): Ensure
buf_ptr is freed.
Calling tui_enable too early in tui_layout_command can leave the tui in
an enabled state if the user has entered an invalid layout name.
Instead postpone the call to tui_enable until later in
tui_set_layout_for_display_command just before the layout is changed.
gdb/ChangeLog:
* tui/tui-layout.c (tui_layout_command): Move call to tui_enable
into ...
(tui_set_layout_for_display_command): ...here, before calling
tui_set_layout. Only set the layout if gdb has not already
entered the TUI_FAILURE state.
Add layout name completion for the layout command.
gdb/ChangeLog:
* tui/tui-layout.c (layout_completer): New function.
(_initialize_tui_layout): Set completer on layout command.
gdb/testsuite/ChangeLog:
* gdb.base/completion.exp: Add test for completion of layout
names.
The layout command supports the layout names $FREGS, $GREGS, $SREGS,
and $REGS. The intention of these layout names was to display the tui
register window with a specific set of registers.
First, these layout names no longer work, and haven't for a while, using
any of them will just result in switching to the general register view.
Second there is already the command 'tui reg GROUP' command to set the
displayed register set to GROUP, so making the layout command also
control the register set feels like unnecessary overloading of the
layout command.
This commit removes all code relating to supporting the register set
specific names from the layout command. Afterwards the user can select
an available layout using the layout command, and control the choice of
register set using the 'tui reg GROUP' command.
gdb/ChangeLog:
* tui/tui-layout.c (tui_set_layout): Remove
tui_register_display_type parameter. Remove all checking of this
parameter, and reindent function. Update header comment.
(tui_set_layout_for_display_command): Rename to...
(tui_set_layout_by_name): ...this, and don't check for different
register class types, don't pass a tui_register_display_type to
tui_set_layout. Update header comment.
(layout_names): Remove register set specific names.
* tui/tui-layout.h (tui_set_layout): Remove
tui_register_display_type parameter.
* tui/tui.c (tui_rl_change_windows): Don't pass a
tui_register_display_type to tui_set_layout.
(tui_rl_delete_other_windows): Likewise.
(tui_enable): Likewise.
* tui/tui-data.h (TUI_FLOAT_REGS_NAME): Remove.
(TUI_FLOAT_REGS_NAME_LOWER): Remove.
(TUI_GENERAL_REGS_NAME): Remove.
(TUI_GENERAL_REGS_NAME_LOWER): Remove.
(TUI_SPECIAL_REGS_NAME): Remove.
(TUI_SPECIAL_REGS_NAME_LOWER): Remove.
(TUI_GENERAL_SPECIAL_REGS_NAME): Remove.
(TUI_GENERAL_SPECIAL_REGS_NAME_LOWER): Remove.
(enum tui_register_display_type): Remove.
(struct tui_layout_def): Remove regs_display_type and
float_regs_display_type fields.
(struct tui_data_info): Remove regs_display_type field.
(tui_layout_command): Use new name for
tui_set_layout_for_display_command.
* tui/tui-data.c (layout_def): Don't initialise removed fields.
(tui_clear_win_detail): Don't initialise removed fields of
win_info.
* tui/tui-regs.c (tui_show_registers): Use new name for
tui_set_layout_for_display_command.
* tui/tui.h (tui_set_layout_for_display_command): Rename
declaration to...
(tui_set_layout_by_name): ...this.
* printcmd.c (display_command): Remove tui related layout call,
and reindent.
The function tui_dispatch_ctrl_char() has an old workaround (from 1999)
for buggy terminals and/or ncurses library that don't return page
up/down keys as single characters. Because the workaround is so old, I
think the bug it is targetting is no longer relevant anymore.
But more importantly, the workaround is itself buggy: it 1) performs a
blocking call to wgetch() and 2) if the key returned by wgetch() does
not make up a relevant key sequence it throws away the input instead of
pushing it back via ungetch(). And indeed the workaround breaks Alt-key
sequences under TERM=xterm because of bug #2.
So this patch removes the buggy workaround and tidies up the function
accordingly.
I personally tested this change on a recent xterm (with TERM=xterm) in
Fedora 20 and had no problems with having ncurses properly interpret
page up/down keys. And Alt-key sequences now work when TERM=xterm too.
gdb/ChangeLog:
* tui/tui-command.c: Remove include of <ctype.h>.
(tui_dispatch_ctrl_char): Remove workaround for xterm terminals.
The control variable win_resized must be cleared before responding to
it.
Otherwise there is a small window where another SIGWINCH might occur in
between the handling of an earlier SIGWINCH and the clearing of
win_resized, at which point win_resized would be set (again) by the
signal handler. Shortly thereafter we would clear win_resized even
though we only handled the earlier SIGWINCH but not the latest one.
This chain of events is all avoided if we clear win_resized first.
gdb/ChangeLog:
* tui/tui-win.c (tui_async_resize_screen): Clear win_resized
first before resizing the window.
* tui.c (tui_enable): Likewise.
When in the CLI, GDB's "width" and "height" variables are not kept in sync
when the underlying terminal gets resized.
This patch fixes this issue by making sure sure to update GDB's "width"
and "height" variables in the !tui_active case of our SIGWINCH handler.
gdb/ChangeLog:
* tui/tui-win.c (tui_sigwinch_handler): Remove now-stale comment.
(tui_sigwinch_handler): Still update our idea of
the terminal's width and height even when TUI is not active.
... to replace the roundabout pattern of
execute_command ("set width %d");
execute_command ("set height %d");
for doing the same thing.
gdb/ChangeLog:
* utils.h (set_screen_width_and_height): Declare.
* utils.c (set_screen_width_and_height): Define.
* tui/tui-win.c (tui_update_gdb_sizes): Use it.
In tui_set_source_content(), when offset == 0 the source and destination
pointers of the call to strcpy() are actually the same. In this case
not only is strcpy() unnecessary but it is also UB when the two strings
overlap.
gdb/ChangeLog:
* tui/tui-source.c (tui_set_source_content): Avoid calling
strcpy() when offset is 0.
For no good reason the function tui_free_window() is freeing the locator
window when we pass it an SRC_WIN or a DISASSEM_WIN. This behavior
doesn't make much sense because the locator window is always visible and
its contents do not change when the main window changes.
This behavior triggers the above PR because when we switch from one TUI
window to another (in the PR, from the src window to the asm window) we
call tui_free_window() on the previously active window (in the PR, the
src window). The function then frees the src window along with the
locator window and later we segfault when the now-active asm window
tries to query the locator window about the inferior's PC.
This patch fixes this apparently wrong behavior by changing
tui_free_window() to not free the locator window when we pass it an
SRC_WIN or a DISASSEM_WIN.
gdb/ChangeLog:
PR gdb/18155
* tui/tui-data.c (tui_free_window): Don't free the locator
window when passed an SRC_WIN or a DISASSEM_WIN.
The 'content' field of struct tui_gen_win_info currently has type
void ** but the field always stores an object of type tui_win_content.
Instead of unnecessarily casting to and from void ** we should just give
the field the type tui_win_content in the first place.
This patch does this and also eliminates all now-redundant casts
involving the 'content' struct field that I could find.
gdb/ChangeLog:
* tui/tui-data.h (struct tui_win_element): Forward-declare.
(tui_win_content): Move declaration.
(struct tui_gen_win_info): Give 'content' field the
type tui_win_content.
* tui/tui-data.c (init_content_element): Remove redundant and
erroneous casts.
(tui_add_content_elements): Remove erroneous cast.
* tui/tui-disasm.c (tui_set_disassem_content): Remove redundant
casts.
(tui_get_begin_asm_address): Likewise.
* tui/tui-regs.c (tui_show_registers): Likewise.
(tui_show_register_group): Likewise.
(tui_display_registers_from): Likewise.
(tui_check_register_values): Likewise.
* tui/tui-source.c (tui_set_source_content): Likewise.
(tui_set_source_content_nil): Likewise.
(tui_source_is_displayed): Likewise.
* tui/tui-stack.c (tui_show_locator_content): Likewise.
(tui_set_locator_fullname): Likewise.
(tui_set_locator_info): Likewise.
(tui_show_frame_info): Likewise.
* tui/tui-winsource.c (tui_clear_source_content): Likewise.
(tui_show_source_line): Likewise.
(tui_horizontal_source_scroll): Likewise.
(tui_update_breakpoint_info): Likewise.
(tui_set_exec_info_content): Likewise.
(tui_show_exec_info_content): Likewise.
(tui_alloc_source_buffer): Likewise.
(tui_line_is_displayed): Likewise.
(tui_addr_is_displayed): Likewise.
In readline 6.3, the semantics of SIGWINCH handling has changed.
When a SIGWINCH signal is raised, readline's rl_sigwinch_handler() now
does not immediately call rl_resize_terminal(). Instead it sets a flag
that is checked by RL_CHECK_SIGNALS() at a point where readline has
control, and calls rl_resize_terminal() if said flag is set.
This change is item (c) in https://cnswww.cns.cwru.edu/php/chet/readline/CHANGES
c. Fixed a bug that caused readline to try and run code to modify its idea
of the screen size in a signal handler context upon receiving a SIGWINCH.
This change in behavior is important to us because TUI's
tui_sigwinch_handler() relies on the assumption that by the time it's
called, readline will have updated its knowledge of the terminal
dimensions via rl_resize_terminal(). Since this assumption no longer
holds true, TUI's SIGWINCH handling does not work correctly with
readline 6.3.
To fix this issue this patch makes TUI explicitly call
rl_resize_terminal() in tui_async_resize_screen() at the point where
current terminal dimensions are needed. (We could call it in
tui_sigwinch_handler too, but since readline avoids doing it, we are
probably safer off avoiding to call it in signal handler context as
well.) After this change, SIGWINCH handling continues to work properly
with both readline 6.2 and 6.3.
Since we no longer need it, we could now explicitly disable readline's
SIGWINCH handler by setting rl_catch_sigwinch to zero early on in the
program startup but I can't seem to find a good spot to place this
assignment (the first call to rl_initialize() occurs in
tui_initialize_readline() so the assignment should occur before then),
and the handler is harmless anyway.
gdb/ChangeLog:
* tui/tui-win.c (tui_async_resize_screen): Call
rl_resize_terminal().
Pedro Alves:
The commands that enables aren't even documented in the manual.
Judging from that, I assume that only wdb users would ever really
be using the --xdb switch.
I think it's time to drop "support" for the --xdb switch too. I
looked through the commands that that exposes, the only that looked
potentially interesting was "go", but then it's just an alias
for "tbreak+jump", which can easily be done with "define go...end".
I'd rather free up the "go" name for something potentially
more interesting (either run control, or maybe even unrelated,
e.g., for golang).
gdb/ChangeLog
2015-04-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* NEWS (Changes since GDB 7.9): Add removed -xdb.
* breakpoint.c (command_line_is_silent): Remove xdb_commands
conditional.
(_initialize_breakpoint): Remove xdb_commands for bc, ab, sb, db, ba
and lb.
* cli/cli-cmds.c (_initialize_cli_cmds): Remove xdb_commands for v and
va.
* cli/cli-decode.c (find_command_name_length): Remove xdb_commands
conditional.
* defs.h (xdb_commands): Remove declaration.
* f-valprint.c (_initialize_f_valprint): Remove xdb_commands for lc.
* guile/scm-cmd.c (command_classes): Remove xdb from comment.
* infcmd.c (run_no_args_command, go_command): Remove.
(_initialize_infcmd): Remove xdb_commands for S, go, g, R and lr.
* infrun.c (xdb_handle_command): Remove.
(_initialize_infrun): Remove xdb_commands for lz and z.
* main.c (xdb_commands): Remove variable.
(captured_main): Remove "xdb" from long_options.
(print_gdb_help): Remove --xdb from help.
* python/py-cmd.c (gdbpy_initialize_commands): Remove xdb from comment.
* source.c (_initialize_source): Remove xdb_commands for D, ld, / and ?.
* stack.c (backtrace_full_command, args_plus_locals_info)
(current_frame_command): Remove.
(_initialize_stack): Remove xdb_commands for t, T and l.
* symtab.c (_initialize_symtab): Remove xdb_commands for lf and lg.
* thread.c (_initialize_thread): Remove xdb_commands condition.
* tui/tui-layout.c (tui_toggle_layout_command)
(tui_toggle_split_layout_command, tui_handle_xdb_layout): Remove.
(_initialize_tui_layout): Remove xdb_commands for td and ts.
* tui/tui-regs.c (tui_scroll_regs_forward_command)
(tui_scroll_regs_backward_command): Remove.
(_initialize_tui_regs): Remove xdb_commands for fr, gr, sr, +r and -r.
* tui/tui-win.c (tui_xdb_set_win_height_command): Remove.
(_initialize_tui_win): Remove xdb_commands for U and w.
* utils.c (pagination_on_command, pagination_off_command): Remove.
(initialize_utils): Remove xdb_commands for am and sm.
gdb/doc/ChangeLog
2015-04-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.texinfo (Mode Options): Remove -xdb.
gdb/ChangeLog:
* tui/tui-io.c (tui_expand_tabs): Reinitialize the column counter
before the second loop, to avoid undefined behavior. Reported by
Anton Blanchard <anton@samba.org>.
This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
This commit introduces a new inline common function "startswith"
which takes two string arguments and returns nonzero if the first
string starts with the second. It also updates the 295 places
where this logic was written out longhand to use the new function.
gdb/ChangeLog:
* common/common-utils.h (startswith): New inline function.
All places where this logic was used updated to use the above.
In C++, we can't do arithmetic on enums. This patch fixes build errors like:
src/gdb/i386-tdep.c: In function ‘int i386_stap_parse_special_token(gdbarch*, stap_parse_info*)’:
src/gdb/i386-tdep.c:4309:7: error: no match for ‘operator++’ (operand type is ‘i386_stap_parse_special_token(gdbarch*, stap_parse_info*)::<anonymous enum>’)
++current_state;
^
...
src/gdb/rs6000-tdep.c:4265:18: error: no match for ‘operator++’ (operand type is ‘powerpc_vector_abi’)
src/gdb/arm-tdep.c:9428:71: error: no match for ‘operator++’ (operand type is ‘arm_float_model’)
src/gdb/arm-tdep.c:9465:64: error: no match for ‘operator++’ (operand type is ‘arm_abi_kind’)
...
gdb/ChangeLog:
2015-02-27 Tom Tromey <tromey@redhat.com>
Pedro Alves <palves@redhat.com>
* arm-tdep.c (set_fp_model_sfunc, arm_set_abi): Use 'int' for
local used to iterate over enums.
* completer.c (signal_completer): Likewise.
* i386-tdep.c (i386_stap_parse_special_token): Likewise.
* rs6000-tdep.c (powerpc_set_vector_abi): Likewise.
* tui/tui-data.c (tui_next_win, tui_prev_win): Likewise.
* tui/tui-layout.c (next_layout, prev_layout): Likewise.
* tui/tui-win.c (tui_refresh_all_win, tui_rehighlight_all)
(tui_resize_all, tui_set_focus_command, tui_all_windows_info): Likewise.
* tui-wingeneral.c (tui_refresh_all): Likewise.
In C, an enum or structure defined inside other structure has global
scope just like it had been defined outside the struct in the first
place. However, in C++, such a nested structure is given a name that
is nested inside the structure. This patch moves such affected
structures/enums out to global scope, so that code using them works
the same in C++ as it works today in C.
gdb/ChangeLog:
2015-02-27 Tom Tromey <tromey@redhat.com>
Pedro Alves <palves@redhat.com>
* dwarf2-frame.c (enum cfa_how_kind, struct
dwarf2_frame_state_reg_info): Move out of struct
dwarf2_frame_state.
* dwarf2read.c (struct tu_stats): Move out of struct
dwarf2_per_objfile.
(struct file_entry): Move out of struct line_header.
(struct nextfield, struct nextfnfield, struct fnfieldlist, struct
typedef_field_list): Move out of struct field_info.
* gdbtypes.h (enum dynamic_prop_kind, union dynamic_prop_data):
Move out of struct dynamic_prop.
(union type_owner, union field_location, struct field, struct
range_bounds, union type_specific): Move out of struct main_type.
(struct fn_fieldlist, struct fn_field, struct typedef_field)
(VOFFSET_STATIC): Move out of struct cplus_struct_type.
(struct call_site_target, union call_site_parameter_u, struct
call_site_parameter): Move out of struct call_site.
* m32c-tdep.c (enum m32c_prologue_kind): Move out of struct
m32c_prologue.
(enum srcdest_kind): Move out of struct srcdest.
* main.c (enum cmdarg_kind): Move out of struct cmdarg.
* prologue-value.h (enum prologue_value_kind): Move out of struct
prologue_value.
* s390-linux-tdep.c (enum s390_abi_kind): Move out of struct
gdbarch_tdep.
* stabsread.c (struct nextfield, struct next_fnfieldlist): Move
out of struct field_info.
* symfile.h (struct other_sections): Move out of struct
section_addr_info.
* symtab.c (struct symbol_cache_slot): Move out struct
block_symbol_cache.
* target-descriptions.c (enum tdesc_type_kind): Move out of
typedef struct tdesc_type.
* tui/tui-data.h (enum tui_line_or_address_kind): Move out of
struct tui_line_or_address.
* value.c (enum internalvar_kind, union internalvar_data): Move
out of struct internalvar.
* xtensa-tdep.h (struct ctype_cache): Move out of struct
gdbarch_tdep.
This patch renames symbols that happen to have names which are
reserved keywords in C++.
Most of this was generated with Tromey's cxx-conversion.el script.
Some places where later hand massaged a bit, to fix formatting, etc.
And this was rebased several times meanwhile, along with re-running
the script, so re-running the script from scratch probably does not
result in the exact same output. I don't think that matters anyway.
gdb/
2015-02-27 Tom Tromey <tromey@redhat.com>
Pedro Alves <palves@redhat.com>
Rename symbols whose names are reserved C++ keywords throughout.
gdb/gdbserver/
2015-02-27 Tom Tromey <tromey@redhat.com>
Pedro Alves <palves@redhat.com>
Rename symbols whose names are reserved C++ keywords throughout.
This patch teaches the TUI to resize itself asynchronously instead of
synchronously. Asynchronously resizing the screen when the underlying
terminal gets resized is the more intuitive behavior and is surprisingly
simple to implement thanks to GDB's async infrastructure.
The implementation is straightforward. TUI's SIGWINCH handler is just
tweaked to asynchronously invoke a new callback,
tui_async_resize_screen, which is responsible for safely resizing the
screen. Care must be taken to not to attempt to asynchronously resize
the screen while the TUI is not active. When the TUI is not active, the
callback will do nothing, but the screen will yet be resized in the next
call to tui_enable() by virtue of win_resized being TRUE.
(So, after the patch there are still two places where the screen gets
resized: one in tui_enable() and the other now in
tui_async_resize_screen() as opposed to being in
tui_handle_resize_during_io(). The one in tui_enable() is still
necessary to handle the case where the terminal gets resized inside the
CLI: in that case, the TUI still needs resizing, but it must wait until
the TUI gets re-enabled.)
gdb/ChangeLog:
* tui/tui-io.c (tui_handle_resize_during_io): Remove this
function.
(tui_putc): Don't call tui_handle_resize_during_io.
(tui_getc): Likewise.
(tui_mld_getc): Likewise.
* tui/tui-win.c: Include event-loop.h and tui/tui-io.h.
(tui_sigwinch_token): New static variable.
(tui_initialize_win): Adjust documentation. Set
tui_sigwinch_token.
(tui_async_resize_screen): New asynchronous callback.
(tui_sigwinch_handler): Adjust documentation. Asynchronously
invoke tui_async_resize_screen.
The function key_is_command_char() is simply a predicate that determines
whether the function tui_dispatch_ctrl_char() will do anything useful.
Since tui_dispatch_ctrl_char() performs the same checks as
key_is_command_char() it is unnecessary to keep key_is_command_char()
around. This patch removes this useless function and instead
unconditionally calls tui_dispatch_ctrl_char() inside its only caller,
tui_getc().
gdb/ChangeLog:
* tui/tui-io.c (tui_getc): Don't call key_is_command_char.
(key_is_command_char): Delete.
If the user:
#1 - disables the TUI
#2 - resizes the terminal
#3 - and then re-enables the TUI
the next wgetch() returns KEY_RESIZE. This indicates to the ncurses
client that ncurses detected that the terminal has been resized. We
don't handle KEY_RESIZE anywhere, so it gets passed on to readline
which interprets it as a multibyte character, and then the end result
is that the first key press after enabling the TUI is misinterpreted.
We shouldn't really need to handle KEY_RESIZE (and not all ncurses
implementations have that). We have our own SIGWINCH handler, and,
when we re-enable the TUI, we explicitly detect terminal resizes and
resize all windows. The reason ncurses currently does detects a
resize is that something within tui_enable forces a refresh/display of
some window before we get to do the actual resizing. Setting a break
on ncurses' 'resizeterm' function helps find the culprit(s):
(top-gdb) bt
#0 resizeterm (ToLines=28, ToCols=114) at ../../ncurses/base/resizeterm.c:462
#1 0x0000003b42812f3f in _nc_update_screensize (sp=0x2674730) at ../../ncurses/tinfo/lib_setup.c:443
#2 0x0000003b0821cbe0 in doupdate () at ../../ncurses/tty/tty_update.c:726
#3 0x0000003b08215539 in wrefresh (win=0x2a7bc00) at ../../ncurses/base/lib_refresh.c:65
#4 0x00000000005257cb in tui_refresh_win (win_info=0xd73d60 <_locator>) at /home/pedro/gdb/mygit/src/gdb/tui/tui-wingeneral.c:60
#5 0x000000000052265b in tui_show_locator_content () at /home/pedro/gdb/mygit/src/gdb/tui/tui-stack.c:269
#6 0x00000000005273a6 in tui_set_key_mode (mode=TUI_COMMAND_MODE) at /home/pedro/gdb/mygit/src/gdb/tui/tui.c:321
#7 0x00000000005278c7 in tui_enable () at /home/pedro/gdb/mygit/src/gdb/tui/tui.c:494
#8 0x0000000000527011 in tui_rl_switch_mode (notused1=1, notused2=1) at /home/pedro/gdb/mygit/src/gdb/tui/tui.c:108
That is, tui_enable calls tui_set_key_mode before we've resized all
windows, and that refreshes a window as side effect.
And if we're already debugging something (there's a frame), then we'll
instead show a window from within tui_show_frame_info:
(top-gdb) bt
#0 resizeterm (ToLines=28, ToCols=114) at ../../ncurses/base/resizeterm.c:462
#1 0x0000003b42812f3f in _nc_update_screensize (sp=0x202e6c0) at ../../ncurses/tinfo/lib_setup.c:443
#2 0x0000003b0821cbe0 in doupdate () at ../../ncurses/tty/tty_update.c:726
#3 0x0000003b08215539 in wrefresh (win=0x2042890) at ../../ncurses/base/lib_refresh.c:65
#4 0x00000000005257cb in tui_refresh_win (win_info=0xd73d60 <_locator>) at /home/pedro/gdb/mygit/src/gdb/tui/tui-wingeneral.c:60
#5 0x000000000052265b in tui_show_locator_content () at /home/pedro/gdb/mygit/src/gdb/tui/tui-stack.c:269
#6 0x0000000000522931 in tui_show_frame_info (fi=0x16b9cc0) at /home/pedro/gdb/mygit/src/gdb/tui/tui-stack.c:364
#7 0x00000000005278ba in tui_enable () at /home/pedro/gdb/mygit/src/gdb/tui/tui.c:491
#8 0x0000000000527011 in tui_rl_switch_mode (notused1=1, notused2=1) at /home/pedro/gdb/mygit/src/gdb/tui/tui.c:108
The fix is to resize windows earlier.
gdb/ChangeLog:
2015-02-17 Pedro Alves <palves@redhat.com>
* tui/tui.c (tui_enable): Resize windows before anything
might show a window.
This patch fixes a pair of TUI issues related to screen resizing:
1. In tui_handle_resize_during_io(), when the TUI screen gets resized,
we fail to update GDB's idea about the height of the output window.
You can see this bug by doing:
a. Enter TUI mode.
b. "show height"
c. Resize the terminal.
d. "show height"
And observe that despite resizing the terminal, the reported height
remains unchanged. Note that a similar issue exists in the CLI.
The fix for this is simple: call tui_update_gdb_sizes() after performing
a resize, so that the "height" variable remains consistent with the
height of TUI's output window.
2. In tui_enable(), the call to tui_update_gdb_sizes() may clobber
readline's idea of the actual screen dimensions, and a subsequent
pending resize will use bogus terminal dimensions.
You can see this bug by doing:
a. Enter TUI mode.
b. Exit TUI mode.
c. Resize the terminal.
d. Enter TUI mode.
e. Press a key to resize the screen.
And observe that the terminal gets incorrectly resized to the wrong
dimensions. To fix this issue, we should oppurtunistically resize the
screen in tui_enable(). That way we eliminate the possibility of a
pending resize triggering right after we call tui_update_gdb_sizes().
gdb/ChangeLog:
* tui/tui-io.c (tui_handle_resize_during_io): Call
tui_update_gdb_sizes() after resizing the screen.
* tui/tui.c (tui_enable): Resize the terminal before
calling tui_update_gdb_sizes().
If we submit a command while the prompt cursor is somewhere other than
at the end of the command line, the command line gets truncated as the
command window gets shifted one line up. This happens because we fail
to properly move the cursor to the end of the command line before
transmitting the newline to ncurses. We need to move the cursor because
when ncurses outputs a newline it truncates any text that appears
past the end of the cursor.
The fix is generic enough to work properly even in multi-line secondary
prompts like the quit prompt.
gdb/ChangeLog:
* tui/tui-io.c (tui_getc): Move cursor to the end of the command
line before printing a newline.
In the TUI mode, we call wrefresh after outputting every single
character. This results in the I/O becoming very slow. Fix this by
delaying refreshing the console window until an explicit flush of
gdb_stdout is requested, or a write to any other (unbuffered) file is
done.
2015-02-04 Doug Evans <dje@google.com>
Pedro Alves <palves@redhat.com>
Eli Zaretskii <eliz@gnu.org>
PR tui/17810
* tui/tui-command.c (tui_refresh_cmd_win): New function.
* tui/tui-command.c (tui_refresh_cmd_win): Declare.
* tui/tui-file.c: #include tui/tui-command.h.
(tui_file_fputs): Refresh command window if stream is not gdb_stdout.
(tui_file_flush): Refresh command window if stream is gdb_stdout.
* tui/tui-io.c (tui_puts): Remove calls to wrefresh, fflush.
This commit adds a new exception, MAX_COMPLETIONS_REACHED_ERROR, to be
thrown whenever the completer has generated too many candidates to
be useful. A new user-settable variable, "max_completions", is added
to control this behaviour. A top-level completion limit is added to
complete_line_internal, as the final check to ensure the user never
sees too many completions. An additional limit is added to
default_make_symbol_completion_list_break_on, to halt time-consuming
symbol table expansions.
gdb/ChangeLog:
PR cli/9007
PR cli/11920
PR cli/15548
* cli/cli-cmds.c (complete_command): Notify user if max-completions
reached.
* common/common-exceptions.h (enum errors)
<MAX_COMPLETIONS_REACHED_ERROR>: New value.
* completer.h (get_max_completions_reached_message): New declaration.
(max_completions): Likewise.
(completion_tracker_t): New typedef.
(new_completion_tracker): New declaration.
(make_cleanup_free_completion_tracker): Likewise.
(maybe_add_completion_enum): New enum.
(maybe_add_completion): New declaration.
(throw_max_completions_reached_error): Likewise.
* completer.c (max_completions): New global variable.
(new_completion_tracker): New function.
(free_completion_tracker): Likewise.
(make_cleanup_free_completion_tracker): Likewise.
(maybe_add_completions): Likewise.
(throw_max_completions_reached_error): Likewise.
(complete_line): Remove duplicates and limit result to max_completions
entries.
(get_max_completions_reached_message): New function.
(gdb_display_match_list): Handle max_completions.
(_initialize_completer): New declaration and function.
* symtab.c: Include completer.h.
(completion_tracker): New static variable.
(completion_list_add_name): Call maybe_add_completion.
(default_make_symbol_completion_list_break_on_1): Renamed from
default_make_symbol_completion_list_break_on. Maintain
completion_tracker across calls to completion_list_add_name.
(default_make_symbol_completion_list_break_on): New function.
* top.c (init_main): Set rl_completion_display_matches_hook.
* tui/tui-io.c: Include completer.h.
(tui_old_rl_display_matches_hook): New static global.
(tui_rl_display_match_list): Notify user if max-completions reached.
(tui_setup_io): Save/restore rl_completion_display_matches_hook.
* NEWS (New Options): Mention set/show max-completions.
gdb/doc/ChangeLog:
* gdb.texinfo (Command Completion): Document new
"set/show max-completions" option.
gdb/testsuite/ChangeLog:
* gdb.base/completion.exp: Disable completion limiting for
existing tests. Add new tests to check completion limiting.
* gdb.linespec/ls-errs.exp: Disable completion limiting.
This copies a lot of code from readline, but this is temporary.
Readline currently doesn't export what we need.
The plan is to have something that has been working for awhile,
and then we'll have a complete story to present to the readline
maintainers.
gdb/ChangeLog:
* cli-out.c: #include completer.h, readline/readline.h.
(cli_mld_crlf, cli_mld_putch, cli_mld_puts): New functions.
(cli_mld_flush, cld_mld_erase_entire_line): Ditto.
(cli_mld_beep, cli_mld_read_key, cli_display_match_list): Ditto.
* cli-out.h (cli_display_match_list): Declare.
* completer.c (MB_INVALIDCH, MB_NULLWCH): New macros.
(ELLIPSIS_LEN): Ditto.
(gdb_get_y_or_n, gdb_display_match_list_pager): New functions.
(gdb_path_isdir, gdb_printable_part, gdb_fnwidth): Ditto.
(gdb_fnprint, gdb_print_filename): Ditto.
(gdb_complete_get_screenwidth, gdb_display_match_list_1): Ditto.
(gdb_display_match_list): Ditto.
* completer.h (mld_crlf_ftype, mld_putch_ftype): New typedefs.
(mld_puts_ftype, mld_flush_ftype, mld_erase_entire_line_ftype): Ditto.
(mld_beep_ftype, mld_read_key_ftype): Ditto.
(match_list_displayer): New struct.
(gdb_display_match_list): Declare.
* top.c (init_main): Set rl_completion_display_matches_hook.
* tui/tui-io.c: #include completer.h.
(printable_part, PUTX, print_filename, get_y_or_n): Delete.
(tui_mld_crlf, tui_mld_putch, tui_mld_puts): New functions.
(tui_mld_flush, tui_mld_erase_entire_line, tui_mld_beep): Ditto.
(tui_mld_getc, tui_mld_read_key): Ditto.
(tui_rl_display_match_list): Rewrite.
(tui_handle_resize_during_io): New arg for_completion. All callers
updated.
gdb/
2015-01-31 Eli Zaretskii <eliz@gnu.org>
* tui/tui-io.c (tui_expand_tabs): New function.
(tui_puts, tui_redisplay_readline): Expand TABs into the
appropriate number of spaces.
* tui/tui-regs.c: Include tui-io.h.
(tui_register_format): Call tui_expand_tabs to expand TABs into
the appropriate number of spaces.
* tui/tui-io.h: Add prototype for tui_expand_tabs.
gdb/
2015-01-22 Eli Zaretskii <eliz@gnu.org>
* gdb/tui/tui.c (tui_enable) [__MINGW32__]: If the call to 'newterm'
fails with the 1st arg NULL, try again with "unknown". Don't test
the "cup" capability: it isn't supported by the Windows port of
ncurses, but the Windows console driver is still capable of
supporting TUI.
gdb/
2015-01-16 Eli Zaretskii <eliz@gnu.org>
* tui/tui-win.c (tui_rehighlight_all, tui_set_var_cmd): New
functions.
(_initialize_tui_win) <border-kind, border-mode>:
<active-border-mode>: Use tui_set_var_cmd as the "set" function.
* tui/tui-win.h: Add prototype for tui_rehighlight_all.
gdb/ChangeLog:
2015-01-16 Eli Zaretskii <eliz@gnu.org>
* tui/tui-win.c (tui_set_tab_width_command): Delete and
recreate the source and the disassembly windows, to show the
effect of the changed tab size immediately.
tui/tui-win.c (tui_scroll_left_command, tui_scroll_right_command):
Doc fix.
doc/gdb.texinfo (TUI Commands): Document the possible
values of NAME argument to 'winheight' command. Explain the
effect of 'tabset' setting better.
gdb/tui/tui-data.h (LINE_PREFIX): Make shorter
(MAX_PID_WIDTH): Enlarge from 14 to 19, to leave enough space for
"Thread NNNNN.XXXX" thread ID notation on Windows.
This patch primarily rewrites defaulted_query() to use
gdb_readline_wrapper() to prompt the user for input, like
prompt_for_continue() does. The motivation for this rewrite is to be
able to reuse the default query hook in TUI, obviating the need for a
custom TUI query hook.
However, having TUI use the default query mechanism exposed a couple of
latent bugs in tui_redisplay_readline() related to the handling of
multi-line prompts, in particular GDB's multi-line quit prompt.
The first issue is an off-by-one error in the calculation of the height
of the prompt. The check in question should be col <= prev_col, not c <
prev_col, to properly account for the case when a prompt contains
multiple consecutive newlines. Failing to do so makes TUI have the
wrong idea of the vertical height of the prompt. This patch fixes the
column check.
The second issue is that cur_line does not get updated to reflect the
cursor position if the user's prompt cursor is at the end of the prompt
(i.e. if rl_point == rl_end). cur_line only gets updated if rl_point
lies between 0..rl_end-1 because that is the bounds of the for loop
responsible for updating cur_line. This patch changes the loop's bounds
to 0..rl_end so that cur_line always gets updated.
With these two bug fixes out of the way, the default query mechanism
works well in TUI even with multi-line prompts like GDB's quit prompt.
gdb/ChangeLog:
* utils.c (defaulted_query): Rewrite to use gdb_readline_wrapper
to prompt for input.
* tui/tui-hooks.c (tui_query_hook): Remove.
(tui_install_hooks): Don't set deprecated_query_hook.
* tui/tui-io.c (tui_redisplay_readline): Fix off-by-one error in
height calculation. Always update the command window's cur_line.
SA_RESTART allows system calls to be restarted across a signal handler.
By specifying this flag we fix the issue where if the user is being
prompted to answer yes or no, and the terminal gets resized in the
meantime, the prompt will think that the user sent an EOF and so it will
take the default action for that prompt (in the case of the quit prompt,
it will quit GDB).
gdb/ChangeLog:
* tui/tui-win.c (tui_initialize_win): Specify SA_RESTART when
registering the signal handler.
This patch fixes the annoying bug where key sequences such as Alt_F or
Alt_B (go forward or backwards by a word) do not behave promptly in TUI.
You have to press a third key in order for the key sequence to register.
This is mostly ncurses' fault. Calling wgetch() normally causes ncurses
to read only a single key from stdin. However if the key read is the
start-sequence key (^[ a.k.a. ESC) then wgetch() reads TWO keys from
stdin, storing the 2nd key into an internal FIFO buffer and returning
the start-sequence key. The extraneous read of the 2nd key makes us
miss its corresponding stdin event, so the event loop blocks until a
third key is pressed. This explains why such key sequences do not
behave promptly in TUI.
To fix this issue, we must somehow compensate for the missed stdin event
corresponding to the 2nd byte of a key sequence. This patch achieves
this by hacking up the stdin event handler to conditionally execute the
readline callback multiple times in a row. This is done via a new
global variable, call_stdin_event_handler_again_p, which is set from
tui_getc() when we receive a start-sequence key and notice extra pending
input in the ncurses buffer.
Tested on x86_64-unknown-linux-gnu.
gdb/ChangeLog:
* event-top.h (call_stdin_event_handler_again_p): Declare.
* event-top.c (call_stdin_event_handler_again_p): Define.
(stdin_event_handler): Use it.
* tui/tui-io.c (tui_getc): Prepare to call the stdin event
handler again if there is pending input following a
start sequence.
Basically the problem is that "symtab" is ambiguous.
Is it the primary symtab (where we canonically think of
blockvectors as being stored) or is it for a specific file
(where each file's line table is stored) ?
gdb_disassembly wants the symtab that contains the line table
but is instead getting the primary symtab.
gdb/ChangeLog:
PR symtab/17559
* symtab.c (find_pc_line_symtab): New function.
* symtab.h (find_pc_line_symtab): Declare.
* disasm.c (gdb_disassembly): Call find_pc_line_symtab instead of
find_pc_symtab.
* tui/tui-disasm.c (tui_set_disassem_content): Ditto.
* tui/tui-hooks.c (tui_selected_frame_level_changed_hook): Ditto.
* tui/tui-source.c (tui_vertical_source_scroll): Ditto.
* tui/tui-win.c (make_visible_with_new_height): Ditto.
* tui/tui-winsource.c (tui_horizontal_source_scroll): Ditto.
(tui_display_main): Call find_pc_line_symtab instead of find_pc_line.
gdb/testsuite/ChangeLog:
PR symtab/17559
* gdb.base/line-symtabs.exp: New file.
* gdb.base/line-symtabs.c: New file.
* gdb.base/line-symtabs.h: New file.
Older versions of ncurses' newterm can't take NULL for their ofp and ifp
parameters. Newer versions can, and they fall back on stdout/stdin if
that is the case.
This patch explicitly passes stdout/stdin to the call to newterm to
avoid segfaulting with older ncurses.
gdb/Changelog:
2014-11-04 Simon Marchi <simon.marchi@ericsson.com>
* tui/tui.c (tui_enable): Pass stdout and stdin to newterm.
I noticed that with:
$ TERM=dumb ./gdb -q -nx
<c-x,a>
Cannot enable the TUI: terminal doesn't support cursor addressing [TERM=dumb]
(gdb)
The next key the user types is silently eaten.
The problem is that we're throwing an exception while in a readline
callback that isn't prepared for that:
(top-gdb) bt
#0 tui_enable () at /home/pedro/gdb/mygit/build/../src/gdb/tui/tui.c:388
#1 0x000000000051f47b in tui_rl_switch_mode (notused1=1, notused2=1) at /home/pedro/gdb/mygit/build/../src/gdb/tui/tui.c:101
#2 0x0000000000768d6f in _rl_dispatch_subseq (key=1, map=0xd069c0 <emacs_ctlx_keymap>, got_subseq=0) at /home/pedro/gdb/mygit/build/../src/readline/readline.c:774
#3 0x0000000000768acb in _rl_dispatch_callback (cxt=0x1ce6190) at /home/pedro/gdb/mygit/build/../src/readline/readline.c:686
#4 0x000000000078120b in rl_callback_read_char () at /home/pedro/gdb/mygit/build/../src/readline/callback.c:170
#5 0x0000000000619445 in rl_callback_read_char_wrapper (client_data=0x0) at /home/pedro/gdb/mygit/build/../src/gdb/event-top.c:166
#6 0x000000000061981b in stdin_event_handler (error=0, client_data=0x0) at /home/pedro/gdb/mygit/build/../src/gdb/event-top.c:372
#7 0x000000000061840e in handle_file_event (data=...) at /home/pedro/gdb/mygit/build/../src/gdb/event-loop.c:762
#8 0x00000000006178f5 in process_event () at /home/pedro/gdb/mygit/build/../src/gdb/event-loop.c:339
#9 0x00000000006179bc in gdb_do_one_event () at /home/pedro/gdb/mygit/build/../src/gdb/event-loop.c:403
#10 0x0000000000617a0c in start_event_loop () at /home/pedro/gdb/mygit/build/../src/gdb/event-loop.c:428
Here, in _rl_dispatch_subseq:
769
770 rl_executing_keymap = map;
771
772 rl_dispatching = 1;
773 RL_SETSTATE(RL_STATE_DISPATCHING);
774 (*map[key].function)(rl_numeric_arg * rl_arg_sign, key);
775 RL_UNSETSTATE(RL_STATE_DISPATCHING);
776 rl_dispatching = 0;
777
778 /* If we have input pending, then the last command was a prefix
779 command. Don't change the state of rl_last_func. Otherwise,
GDB is called from line 774, but longjmp'ing at that point leaves
rl_dispatching and RL_STATE_DISPATCHING set.
Fix this by wrapping tui_rl_switch_mode in a TRY_CATCH.
gdb/
2014-10-29 Pedro Alves <palves@redhat.com>
* tui/tui.c (tui_rl_switch_mode): Wrap tui_enable/tui_disable in
TRY_CATCH.
PR tui/16138 is about failure to initialize curses resulting in GDB
exiting instead of throwing an error. E.g.:
$ TERM=foo gdb
(gdb) layout asm
Error opening terminal: foo.
$
The problem is that we're calling initscr to initialize the screen.
As mentioned in
http://pubs.opengroup.org/onlinepubs/7908799/xcurses/initscr.html:
If errors occur, initscr() writes an appropriate error message to
standard error and exits.
^^^^^
Instead, we should use newterm:
"A program that needs an indication of error conditions, so it can
continue to run in a line-oriented mode if the terminal cannot support
a screen-oriented program, would also use this function."
After the patch:
$ TERM=foo gdb -q -nx
(gdb) layout asm
Cannot enable the TUI: error opening terminal [TERM=foo]
(gdb)
And then PR tui/17519 is about GDB not validating whether the terminal
has the necessary capabilities when enabling the TUI. If one tries to
enable the TUI with TERM=dumb (and e.g., from a shell within emacs),
GDB ends up with a clear screen, the cursor is placed at the
bottom/right corner of the screen, there's no prompt, typing shows no
echo, and there's no indication of what's going on. c-x,a gets you
out of the TUI, but it's completely non-obvious.
After the patch, we get:
$ TERM=dumb gdb -q -nx
(gdb) layout asm
Cannot enable the TUI: terminal doesn't support cursor addressing [TERM=dumb]
(gdb)
While at it, I've moved all the tui_allowed_p validation to
tui_enable, and expanded the error messages. Previously we'd get:
$ gdb -q -nx -i=mi
(gdb)
layout asm
&"layout asm\n"
&"TUI mode not allowed\n"
^error,msg="TUI mode not allowed"
and:
$ gdb -q -nx -ex "layout asm" > foo
TUI mode not allowed
While now we get:
$ gdb -q -nx -i=mi
(gdb)
layout asm
&"layout asm\n"
&"Cannot enable the TUI when the interpreter is 'mi'\n"
^error,msg="Cannot enable the TUI when the interpreter is 'mi'"
(gdb)
and:
$ gdb -q -nx -ex "layout asm" > foo
Cannot enable the TUI when output is not a terminal
Tested on x86_64 Fedora 20.
gdb/
2014-10-29 Pedro Alves <palves@redhat.com>
PR tui/16138
PR tui/17519
* tui/tui-interp.c (tui_is_toplevel): Delete global.
(tui_allowed_p): Delete function.
* tui/tui.c: Include "interps.h".
(tui_enable): Don't use tui_allowed_p. Error out here with
detailed error messages if the TUI is the top level interpreter,
or if output is not a terminal. Use newterm instead of initscr,
and error out if initializing the terminal fails. Also error out if
the terminal doesn't support cursor addressing.
* tui/tui.h (tui_allowed_p): Delete declaration.
