Use GCC5/DWARF5 DW_AT_noreturn to mark functions that don't return normally.

Add a flag field is_noreturn to struct func_type. Make calling_convention
a small bit field to not increase the size of the struct. Set is_noreturn
if the new GCC5/DWARF5 DW_AT_noreturn is set on a DW_TAG_subprogram.
Use this information to warn the user before doing a finish or return from
a function that does not return normally to its caller.

(gdb) finish
warning: Function endless does not return normally.
Try to finish anyway? (y or n)

(gdb) return
warning: Function does not return normally to caller.
Make endless return now? (y or n)

gdb/ChangeLog

	* dwarf2read.c (read_subroutine_type): Set TYPE_NO_RETURN from
	DW_AT_noreturn.
	* gdbtypes.h (struct func_type): Add is_noreturn field flag. Make
	calling_convention an 8 bit bit field.
	(TYPE_NO_RETURN): New macro.
	* infcmd.c (finish_command): Query if function does not return
	normally.
	* stack.c (return_command): Likewise.

gdb/testsuite/ChangeLog

	* gdb.base/noreturn-return.c: New file.
	* gdb.base/noreturn-return.exp: New file.
	* gdb.base/noreturn-finish.c: New file.
	* gdb.base/noreturn-finish.exp: New file.

include/ChangeLog

	* dwarf2.def (DW_AT_noreturn): New DWARF5 attribute.

The dwarf2.h addition and the code to emit the new attribute is already in
the gcc tree.
This commit is contained in:
Mark Wielaard 2014-12-09 11:45:41 +01:00
parent 198297aafb
commit 743649fd80
12 changed files with 218 additions and 5 deletions

View File

@ -1,3 +1,14 @@
2015-01-15 Mark Wielaard <mjw@redhat.com>
* dwarf2read.c (read_subroutine_type): Set TYPE_NO_RETURN from
DW_AT_noreturn.
* gdbtypes.h (struct func_type): Add is_noreturn field flag. Make
calling_convention an 8 bit bit field.
(TYPE_NO_RETURN): New macro.
* infcmd.c (finish_command): Query if function does not return
normally.
* stack.c (return_command): Likewise.
2015-01-23 Pedro Alves <palves@redhat.com>
* linux-nat.c (linux_is_async_p): New macro.

View File

@ -14343,6 +14343,12 @@ read_subroutine_type (struct die_info *die, struct dwarf2_cu *cu)
else
TYPE_CALLING_CONVENTION (ftype) = DW_CC_normal;
/* Record whether the function returns normally to its caller or not
if the DWARF producer set that information. */
attr = dwarf2_attr (die, DW_AT_noreturn, cu);
if (attr && (DW_UNSND (attr) != 0))
TYPE_NO_RETURN (ftype) = 1;
/* We need to add the subroutine type to the die immediately so
we don't infinitely recurse when dealing with parameters
declared as the same subroutine type. */

View File

@ -1019,9 +1019,16 @@ struct func_type
{
/* * The calling convention for targets supporting multiple ABIs.
Right now this is only fetched from the Dwarf-2
DW_AT_calling_convention attribute. */
DW_AT_calling_convention attribute. The value is one of the
DW_CC enum dwarf_calling_convention constants. */
unsigned calling_convention;
unsigned calling_convention : 8;
/* * Whether this function normally returns to its caller. It is
set from the DW_AT_noreturn attribute if set on the
DW_TAG_subprogram. */
unsigned int is_noreturn : 1;
/* * Only those DW_TAG_GNU_call_site's in this function that have
DW_AT_GNU_tail_call set are linked in this list. Function
@ -1245,6 +1252,7 @@ extern void allocate_gnat_aux_type (struct type *);
#define TYPE_GNAT_SPECIFIC(thistype) TYPE_MAIN_TYPE(thistype)->type_specific.gnat_stuff
#define TYPE_DESCRIPTIVE_TYPE(thistype) TYPE_GNAT_SPECIFIC(thistype)->descriptive_type
#define TYPE_CALLING_CONVENTION(thistype) TYPE_MAIN_TYPE(thistype)->type_specific.func_stuff->calling_convention
#define TYPE_NO_RETURN(thistype) TYPE_MAIN_TYPE(thistype)->type_specific.func_stuff->is_noreturn
#define TYPE_TAIL_CALL_LIST(thistype) TYPE_MAIN_TYPE(thistype)->type_specific.func_stuff->tail_call_list
#define TYPE_BASECLASS(thistype,index) TYPE_FIELD_TYPE(thistype, index)
#define TYPE_N_BASECLASSES(thistype) TYPE_CPLUS_SPECIFIC(thistype)->n_baseclasses

View File

@ -1872,7 +1872,14 @@ finish_command (char *arg, int from_tty)
if (execution_direction == EXEC_REVERSE)
printf_filtered (_("Run back to call of "));
else
printf_filtered (_("Run till exit from "));
{
if (function != NULL && TYPE_NO_RETURN (function->type)
&& !query (_("warning: Function %s does not return normally.\n"
"Try to finish anyway? "),
SYMBOL_PRINT_NAME (function)))
error (_("Not confirmed."));
printf_filtered (_("Run till exit from "));
}
print_stack_frame (get_selected_frame (NULL), 1, LOCATION, 0);
}

View File

@ -2462,8 +2462,12 @@ return_command (char *retval_exp, int from_tty)
confirmed = query (_("%sMake selected stack frame return now? "),
query_prefix);
else
confirmed = query (_("%sMake %s return now? "), query_prefix,
SYMBOL_PRINT_NAME (thisfun));
{
if (TYPE_NO_RETURN (thisfun->type))
warning ("Function does not return normally to caller.");
confirmed = query (_("%sMake %s return now? "), query_prefix,
SYMBOL_PRINT_NAME (thisfun));
}
if (!confirmed)
error (_("Not confirmed"));
}

View File

@ -1,3 +1,10 @@
2015-01-15 Mark Wielaard <mjw@redhat.com>
* gdb.base/noreturn-return.c: New file.
* gdb.base/noreturn-return.exp: New file.
* gdb.base/noreturn-finish.c: New file.
* gdb.base/noreturn-finish.exp: New file.
2015-01-23 Pedro Alves <palves@redhat.com>
* gdb.threads/continue-pending-after-query.c: New file.

View File

@ -0,0 +1,31 @@
/* This testcase is part of GDB, the GNU debugger.
Copyright 2015 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <stdlib.h>
void __attribute__((noreturn))
noreturn_func (void)
{
abort ();
}
int
main (void)
{
noreturn_func ();
return 0;
}

View File

@ -0,0 +1,51 @@
# Copyright 2015 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
standard_testfile
if [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} {debug}] {
return -1
}
proc noreturn_finish_test { } {
global gdb_prompt
if { ! [ runto_main ] } then {
untested ${testfile}.exp
return -1
}
gdb_breakpoint "noreturn_func"
gdb_continue_to_breakpoint "noreturn_func"
set test "cancel finish from noreturn_func"
gdb_test_multiple "finish" $test {
-re "warning: Function noreturn_func does not return normally" {
verbose -log "saw warning"
exp_continue
}
-re "Try to finish anyway.*y or n.* $" {
send_gdb "n\n"
exp_continue
}
-re ".*$gdb_prompt $" {
pass $test
}
}
}
clean_restart ${binfile}
noreturn_finish_test

View File

@ -0,0 +1,31 @@
/* This testcase is part of GDB, the GNU debugger.
Copyright 2015 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <stdlib.h>
void __attribute__((noreturn))
noreturn_func (void)
{
abort ();
}
int
main (void)
{
noreturn_func ();
return 0;
}

View File

@ -0,0 +1,51 @@
# Copyright 2015 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
standard_testfile
if [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} {debug}] {
return -1
}
proc noreturn_test { } {
global gdb_prompt
if { ! [ runto_main ] } then {
untested ${testfile}.exp
return -1
}
gdb_breakpoint "noreturn_func"
gdb_continue_to_breakpoint "noreturn_func"
set test "cancel return from noreturn_func"
gdb_test_multiple "return" $test {
-re "warning: Function does not return normally to caller" {
verbose -log "saw warning"
exp_continue
}
-re "Make noreturn_func return now.*y or n. $" {
send_gdb "n\n"
exp_continue
}
-re "Not confirmed.*$gdb_prompt $" {
pass $test
}
}
}
clean_restart ${binfile}
noreturn_test

View File

@ -1,3 +1,7 @@
2015-01-15 Mark Wielaard <mjw@redhat.com>
* dwarf2.def (DW_AT_noreturn): New DWARF5 attribute.
2015-01-14 Jan-Benedict Glaw <jbglaw@lug-owl.de>
* libiberty.h: Merge from GCC.

View File

@ -306,6 +306,8 @@ DW_AT (DW_AT_data_bit_offset, 0x6b)
DW_AT (DW_AT_const_expr, 0x6c)
DW_AT (DW_AT_enum_class, 0x6d)
DW_AT (DW_AT_linkage_name, 0x6e)
/* DWARF 5. */
DW_AT (DW_AT_noreturn, 0x87)
DW_AT_DUP (DW_AT_lo_user, 0x2000) /* Implementation-defined range start. */
DW_AT_DUP (DW_AT_hi_user, 0x3fff) /* Implementation-defined range end. */