Re: [PATCH] Fix breakpoint thread condition missing with mi and a pending breakpoint.

[Pedro Alves <palves at redhat dot com>]

On 02/20/2015 07:06 PM, Antoine Tremblay wrote:
> When setting a pending breakpoint with a thread condition while using
> the mi interface, the thread condition would be lost by gdb when the breakpoint
> was resolved.
> 
> This patch fixes this behavior by setting the thread condition properly in the
> mi case.

Took me a bit to figure why this was MI specific.  It's because on the CLI
case, the thread is instead parsed from ARG.

> 
> Also, this patch modifies the mi-pending test case to test for this issue and
> removes some unneeded code in the testcase and dependency on stdio.
> 
> gdb/Changelog:
> 	PR breakpoints/16466
> 	* breakpoint.c (create_breakpoint): Set thread on breakpoint struct.
> 
> gdb/testsuite/ChangeLog:
> 	PR breakpoints/16466
> 	* gdb.mi/Makefile.in: Add mi-pendshr2.sl to cleanup.

	* gdb.mi/Makefile.in (MISCELLANEOUS): Add mi-pendshr2.sl.


> 	* gdb.mi/mi-pending.c (thread_func): Add simple
> 	thread function.

"New function."

> 	(int main): Added threading support required.

 	(NUM): New define.
 	(main): Create two threads.

(I almost requested to create a separate test instead, so that
the original test would still work against targets that
don't do threads, but then, the test relies on shared libraries,
and targets that don't do threads won't be doing those either.)

> 	* gdb.mi/mi-pending.exp: Added tests for this issue.
> 	* gdb.mi/mi-pendshr.c (pendfunc1): Removed stdio dependency.
> 	(pendfunc2): Removed stdio dependency.
> 	* gdb.mi/mi-pendshr2.c: New file.

s/Added/Add
s/Removed/Remove

> ---
>  gdb/breakpoint.c                    |    1 +
>  gdb/testsuite/gdb.mi/Makefile.in    |    2 +-
>  gdb/testsuite/gdb.mi/mi-pending.c   |   42 +++++++++++++++++---
>  gdb/testsuite/gdb.mi/mi-pending.exp |   72 +++++++++++++++++++++++++++++------
>  gdb/testsuite/gdb.mi/mi-pendshr.c   |   13 +++----
>  gdb/testsuite/gdb.mi/mi-pendshr2.c  |   21 ++++++++++
>  6 files changed, 126 insertions(+), 25 deletions(-)
>  create mode 100644 gdb/testsuite/gdb.mi/mi-pendshr2.c
> 
> diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
> index acf1ecf..778a01e 100644
> --- a/gdb/breakpoint.c
> +++ b/gdb/breakpoint.c
> @@ -10159,6 +10159,7 @@ create_breakpoint (struct gdbarch *gdbarch,
>  	      make_cleanup (xfree, cond_string);
>  	    }
>  	  b->cond_string = cond_string;
> +	  b->thread = thread;
>  	}
>        b->extra_string = NULL;
>        b->ignore_count = ignore_count;
> diff --git a/gdb/testsuite/gdb.mi/Makefile.in b/gdb/testsuite/gdb.mi/Makefile.in
> index 661add2..2ea819d 100644
> --- a/gdb/testsuite/gdb.mi/Makefile.in
> +++ b/gdb/testsuite/gdb.mi/Makefile.in
> @@ -16,7 +16,7 @@ PROGS = basics c_variable cpp_variable var-cmd dw2-ref-missing-frame	\
>  	mi2-var-block mi2-var-child mi2-var-cmd mi2-var-display		\
>  	mi2-watch until
>  
> -MISCELLANEOUS = mi-pendshr.sl
> +MISCELLANEOUS = mi-pendshr.sl mi-pendshr2.sl
>  
>  all info install-info dvi install uninstall installcheck check:
>  	@echo "Nothing to be done for $@..."
> diff --git a/gdb/testsuite/gdb.mi/mi-pending.c b/gdb/testsuite/gdb.mi/mi-pending.c
> index 21a2165..7d1b7ae 100644
> --- a/gdb/testsuite/gdb.mi/mi-pending.c
> +++ b/gdb/testsuite/gdb.mi/mi-pending.c
> @@ -15,17 +15,49 @@
>     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 <stdio.h>
> +#include <dlfcn.h>
> +#include <pthread.h>
>  
> -int k = 0;
> +#define NUM 2
>  
>  extern void pendfunc (int x);
>  
> +void*
> +thread_func (void* arg)
> +{
> +  const char *libname = "mi-pendshr2.sl";
> +  void *h;
> +  int (*p_func) ();
> +
> +  h = dlopen (libname, RTLD_LAZY);  /* set breakpoint here */
> +  if (h == NULL) return;
> +
> +  p_func = dlsym (h, "pendfunc3");
> +  if (p_func == NULL) return;

Please put the "return" statements on their own lines.

> +
> +  (*p_func) ();
> +}
> +
>  int main()
>  {
> -  pendfunc (3); /* break main here */
> -  pendfunc (4);
> -  k = 1;
> +  int res;
> +  pthread_t threads[NUM];
> +  int i;
> +
>    pendfunc (3);
> +  pendfunc (4);
> +
> +  for (i = 0; i < NUM; i++)
> +    {
> +      res = pthread_create(&threads[i],
> +			     NULL,
> +			     &thread_func,
> +			     NULL);

Space before parens.

> +    }
> +
> +  for (i = 0; i < NUM; i++) {
> +    res = pthread_join(threads[i], NULL);

Ditto.

> +  }
> +
>    return 0;
>  }
> diff --git a/gdb/testsuite/gdb.mi/mi-pending.exp b/gdb/testsuite/gdb.mi/mi-pending.exp
> index a5d1c5b..3621f47 100644
> --- a/gdb/testsuite/gdb.mi/mi-pending.exp
> +++ b/gdb/testsuite/gdb.mi/mi-pending.exp
> @@ -24,29 +24,39 @@ if {[skip_shlib_tests]} {
>      return 0
>  }
>  
> -standard_testfile mi-pending.c mi-pendshr.c
> -set lib_sl [standard_output_file mi-pendshr.sl]
> +standard_testfile mi-pending.c
>  
> -set lib_opts  debug
> -set exec_opts [list debug shlib=$lib_sl]
> +set libfile1 "mi-pendshr"
> +set libfile2 "mi-pendshr2"
> +set libsrc1  $srcdir/$subdir/$libfile1.c
> +set libsrc2  $srcdir/$subdir/$libfile2.c
> +set lib_sl1  [standard_output_file $libfile1.sl]
> +set lib_sl2  [standard_output_file $libfile2.sl]
> +set lib_opts debug
> +set exec_opts [list debug shlib=$lib_sl1 shlib_load]
>  
>  if [get_compiler_info] {
>      return -1
>  }
>  
> -if { [gdb_compile_shlib $srcdir/$subdir/$srcfile2 $lib_sl $lib_opts] != ""
> -     || [gdb_compile $srcdir/$subdir/$srcfile $binfile executable $exec_opts] != ""} {
> -    untested "Could not compile either $libsrc or $srcdir/$subdir/$srcfile."
> +if { [gdb_compile_shlib $libsrc1 $lib_sl1 $lib_opts] != ""
> +     || [gdb_compile_shlib $libsrc2 $lib_sl2 $lib_opts] != ""} {
> +    untested "Could not compile either $libsrc1 or $libsrc2"
>      return -1
>  }
>  
> -# Start with a fresh gdb.
> +if { [gdb_compile_pthreads $srcdir/$subdir/$srcfile $binfile executable $exec_opts] != ""} {
> +    untested "Could not compile  $srcdir/$subdir/$srcfile."
> +    return -1
> +}

>  
> +# Start with a fresh gdb.
>  gdb_exit
>  mi_gdb_start
>  mi_gdb_reinitialize_dir $srcdir/$subdir
>  mi_gdb_load ${binfile}
> -mi_load_shlibs $lib_sl
> +mi_load_shlibs $lib_sl1
> +mi_load_shlibs $lib_sl2
>  
>  # Set pending breakpoint via MI.
>  mi_gdb_test "-break-insert -f pendfunc1" \
> @@ -54,23 +64,61 @@ mi_gdb_test "-break-insert -f pendfunc1" \
>      "MI pending breakpoint on pendfunc1"
>  
>  # Set pending breakpoint with a condition via MI.
> -mi_gdb_test "-break-insert -f -c x==4 ${srcfile2}:pendfunc2" \
> -    ".*\\^done,bkpt=\{number=\"2\",type=\"breakpoint\",disp=\"keep\",enabled=\"y\",addr=\"<PENDING>\",pending=\"${srcfile2}:pendfunc2\",cond=\"x==4\",times=\"0\",original-location=\"${srcfile2}:pendfunc2\"\}"\
> -    "MI pending breakpoint on ${srcfile2}:pendfunc2 if x==4"
> +mi_gdb_test "-break-insert -f -c x==4 ${libsrc1}:pendfunc2" \
> +    ".*\\^done,bkpt=\{number=\"2\",type=\"breakpoint\",disp=\"keep\",enabled=\"y\",addr=\"<PENDING>\",pending=\"${libsrc1}:pendfunc2\",cond=\"x==4\",times=\"0\",original-location=\"${libsrc1}:pendfunc2\"\}"\
> +    "MI pending breakpoint on ${libsrc1}:pendfunc2 if x==4"
> +
> +# Set breakpoint so that we can stop when the thread is created
> +mi_gdb_test "-break-insert -f thread_func" \
> +    ".*\\^done,bkpt=\{number=\"3\",type=\"breakpoint\",disp=\"keep\",enabled=\"y\",addr=\"${hex}\",func=\"thread_func\".*\}"\
> +    "MI pending breakpoint on thread_func"
>  
>  mi_run_cmd
> +
>  mi_expect_stop "breakpoint-hit" "pendfunc1" ".*" ".*" ".*" \
>      { "" "disp=\"keep\"" } \
>      "Run till MI pending breakpoint on pendfunc1"
>  
>  mi_send_resuming_command "exec-continue" "continuing execution to skip conditional bp"
> +
>  # We should not stop on the conditional breakpoint yet, but we stop on the original bp. 
>  mi_expect_stop "breakpoint-hit" "pendfunc1" ".*" ".*" ".*" \
>      { "" "disp=\"keep\"" } \
>      "Run till MI pending breakpoint on pendfunc1 a second time"
>  
>  mi_send_resuming_command "exec-continue" "continuing execution to conditional bp"
> +
>  # Now we should stop on the conditional breakpoint.
>  mi_expect_stop "breakpoint-hit" "pendfunc2" "\{name=\"x\",value=\"4\"\}" ".*" ".*" \
>      { "" "disp=\"keep\"" } \
>      "Run till MI pending breakpoint on pendfunc2 with x==4"
> +
> +mi_send_resuming_command "exec-continue" "continuing execution to thread creation"
> +
> +# Stop on thread creation so we can set a pending breakpoint with a thread cond.
> +mi_expect_stop "breakpoint-hit" "thread_func" ".*" ".*" ".*" \
> +    { "" "disp=\"keep\"" } \
> +    "Run till MI pending breakpoint on thread_func"
> +
> +# Delete thread creation breakpoint to enable more then 1 thread to be created.

"more than" ?

> +mi_gdb_test "-break-delete 3" ".*" ""
> +

Please make this regex a bit more strict.

> +# Set pending breakpoint with a thread via MI.
> +mi_gdb_test "-break-insert -p 2 -f pendfunc3" \
> +    ".*\\^done,bkpt=\{number=\"4\",type=\"breakpoint\",disp=\"keep\",enabled=\"y\",addr=\"<PENDING>\",pending=\"pendfunc3\",thread=\"2\",thread=\"2\",times=\"0\",original-location=\"pendfunc3\"\}"\
> +    "MI pending breakpoint on pendfunc3"
> +
> +mi_send_resuming_command "exec-continue" "continuing execution to thread condition"
> +
> +# Check if we stopped in thread 2 like we should.
> +set testname "Run till MI pending breakpoint on pendfunc3 on thread 2"
> +gdb_expect 5 {
> +    -re "\\*stopped,reason=\"breakpoint-hit\",disp=\"keep\",bkptno=\"4\",frame=\{addr=\"$hex\",func=\"pendfunc3\".*thread-id=\"2\".*" {
> +	pass $testname
> +	return 0
> +    }
> +    timeout {
> +	fail "$testname (timeout)"
> +	return -1
> +    }
> +}

Can't this use mi_expect_stop ?

Otherwise looks good to me.

Thanks,
Pedro Alves