8sa1-binutils-gdb/gdb/testsuite/gdb.opt/inline-break.c
Pedro Alves 61b04dd04a Change inline frame breakpoint skipping logic (fix gdb.gdb/selftest.exp)
Currently, gdb.gdb/selftest.exp fails if you build GDB with
optimization (-O2, etc.).

The reason is that after setting a breakpoint in captured_main, we
stop at:
 ...
 Breakpoint 1, captured_main_1 (context=<optimized out>) at src/gdb/main.c:492
 ...
while selftest_setup expects a stop at captured_main.

Here, captured_main_1 has been inlined into captured_main, and
captured_main has been inlined into gdb_main:

 ...
 $ nm ./build/gdb/gdb | egrep ' [tT] .*captured_main|gdb_main' | c++filt
 000000000061b950 T gdb_main(captured_main_args*)
 ...

Indeed, the two inlined functions show up in the backtrace:

 ...
 (gdb) bt
 #0  captured_main_1 (context=<optimized out>) at main.c:492
 #1  captured_main (data=<optimized out>) at main.c:1147
 #2  gdb_main (args=args@entry=0x7fffffffdb80) at main.c:1173
 #3  0x000000000040fea5 in main (argc=<optimized out>, argv=<optimized out>)
     at gdb.c:32
 ...

We're now stopping at captured_main_1 because commit ddfe970e6b
("Don't elide all inlined frames") makes GDB present a stop at the
innermost inlined frame if the program stopped by a user breakpoint.

Now, the selftest.exp testcase explicitly asks to stop at
"captured_main", not "captured_main_1", so I'm thinking that it's
GDB'S behavior that should be improved.  That is what this commit
does, by only showing a stop at an inline frame if the user breakpoint
was set in that frame's block.

Before this commit:

 (top-gdb) b captured_main
 Breakpoint 1 at 0x792f99: file src/gdb/main.c, line 492.
 (top-gdb) r
 Starting program: build/gdb/gdb

 Breakpoint 1, captured_main_1 (context=<optimized out>) at src/gdb/main.c:492
 492       lim_at_start = (char *) sbrk (0);
 (top-gdb)

After this commit, we now instead get:

 (top-gdb) b captured_main
 Breakpoint 1 at 0x791339: file src/gdb/main.c, line 492.
 (top-gdb) r
 Starting program: build/gdb/gdb

 Breakpoint 1, captured_main (data=<optimized out>) at src/gdb/main.c:1147
 1147      captured_main_1 (context);
 (top-gdb)

and:

 (top-gdb) b captured_main_1
 Breakpoint 2 at 0x791339: file src/gdb/main.c, line 492.
 (top-gdb) r
 Starting program: build/gdb/gdb
 Breakpoint 2, captured_main_1 (context=<optimized out>) at src/gdb/main.c:492
 492       lim_at_start = (char *) sbrk (0);
 (top-gdb)

Note that both captured_main and captured_main_1 resolved to the same
address, 0x791339.  That is necessary to trigger the issue in
question.  The gdb.base/inline-break.exp testcase currently does not
exercise that, but the new test added by this commit does.  That new
test fails without the GDB fix and passes with the fix.  No
regressions on x86-64 GNU/Linux.

While at it, the THIS_PC comparison in stopped_by_user_bp_inline_frame
is basically a nop, so just remove it -- if a software or hardware
breakpoint explains the stop, then it must be that it was installed at
the current PC.

gdb/ChangeLog:
2018-06-19  Pedro Alves  <palves@redhat.com>

	* inline-frame.c (stopped_by_user_bp_inline_frame): Replace PC
	parameter with a block parameter.  Compare location's block symbol
	with the frame's block instead of addresses.
	(skip_inline_frames): Pass the current block instead of the
	frame's address.  Break out as soon as we determine the frame
	should not be skipped.

gdb/testsuite/ChangeLog:
2018-06-19  Pedro Alves  <palves@redhat.com>

	* gdb.opt/inline-break.c (func_inline_callee, func_inline_caller)
	(func_extern_caller): New.
	(main): Call func_extern_caller.
	* gdb.opt/inline-break.exp: Add tests for inline frame skipping
	logic change.
2018-06-19 16:30:13 +01:00

244 lines
4.4 KiB
C

/* This testcase is part of GDB, the GNU debugger.
Copyright (C) 2012-2018 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/>. */
/* The file ../gdb.dwarf2/inline-break.S was generated manually from
this file, and should be regenerated if this file is modified. */
#ifdef __GNUC__
# define ATTR __attribute__((gnu_inline)) __attribute__((always_inline))
#else
# define ATTR
#endif
/* A static inlined function that is called once. */
static inline ATTR int
func1 (int x)
{
return x * 23;
}
/* A non-static inlined function that is called once. */
inline ATTR int
func2 (int x)
{
return x * 17;
}
/* A static inlined function that calls another static inlined
function. */
static inline ATTR int
func3b (int x)
{
return x < 14 ? 1 : 2;
}
static inline ATTR int
func3a (int x)
{
return func3b (x * 23);
}
/* A non-static inlined function that calls a static inlined
function. */
static inline ATTR int
func4b (int x)
{
return x < 13 ? 1 : 2;
}
inline ATTR int
func4a (int x)
{
return func4b (x * 17);
}
/* A static inlined function that calls a non-static inlined
function. */
inline ATTR int
func5b (int x)
{
return x < 12 ? 1 : 2;
}
static inline ATTR int
func5a (int x)
{
return func5b (x * 23);
}
/* A non-static inlined function that calls another non-static inlined
function. */
inline ATTR int
func6b (int x)
{
return x < 14 ? 3 : 2;
}
inline ATTR int
func6a (int x)
{
return func6b (x * 17);
}
/* A static inlined function that is called more than once. */
static inline ATTR int
func7b (int x)
{
return x < 23 ? 1 : 4;
}
static inline ATTR int
func7a (int x)
{
return func7b (x * 29);
}
/* A non-static inlined function that is called more than once. */
inline ATTR int
func8b (int x)
{
return x < 7 ? 11 : 9;
}
static inline ATTR int
func8a (int x)
{
return func8b (x * 31);
}
static inline ATTR int
inline_func1 (int x)
{
int y = 1; /* inline_func1 */
return y + x;
}
static int
not_inline_func1 (int x)
{
int y = 2; /* not_inline_func1 */
return y + inline_func1 (x);
}
inline ATTR int
inline_func2 (int x)
{
int y = 3; /* inline_func2 */
return y + not_inline_func1 (x);
}
int
not_inline_func2 (int x)
{
int y = 4; /* not_inline_func2 */
return y + inline_func2 (x);
}
static inline ATTR int
inline_func3 (int x)
{
int y = 5; /* inline_func3 */
return y + not_inline_func2 (x);
}
static int
not_inline_func3 (int x)
{
int y = 6; /* not_inline_func3 */
return y + inline_func3 (x);
}
/* The following three functions serve to exercise GDB's inline frame
skipping logic when setting a user breakpoint on an inline function
by name. */
/* A static inlined function that is called by another static inlined
function. */
static inline ATTR int
func_inline_callee (int x)
{
return x * 23;
}
/* A static inlined function that calls another static inlined
function. The body of the function is as simple as possible so
that both functions are inlined to the same PC address. */
static inline ATTR int
func_inline_caller (int x)
{
return func_inline_callee (x);
}
/* An extern not-inline function that calls a static inlined
function. */
int
func_extern_caller (int x)
{
return func_inline_caller (x);
}
/* Entry point. */
int
main (int argc, char *argv[])
{
/* Declaring x as volatile here prevents GCC from combining calls.
If GCC is allowed to combine calls then some of them end up with
no instructions at all, so there is no specific address for GDB
to set a breakpoint at. */
volatile int x = argc;
x = func1 (x);
x = func2 (x);
x = func3a (x);
x = func4a (x);
x = func5a (x);
x = func6a (x);
x = func7a (x) + func7b (x);
x = func8a (x) + func8b (x);
x = not_inline_func3 (-21);
func_extern_caller (1);
return x;
}