[RFA/testsuite] attach.exp: Add small delay in busy loop...

[Michael Snyder]

Joel Brobecker wrote:
> Hello,
> 
> The attach.exp sometimes fails on certain platforms (eg mips-irix),
> and causes an attach process to be left behind. Since it is doing a busy
> loop, this runaway process left behind consumes 99.9% of the CPU,
> and considerably slows down the execution of the rest of the testsuite.
> 
> I suggest the following change to add a small delay at each iteration
> of the busy loop. I had to make some adjustments to attach.exp:
> 
>   a. Line number 19 became line 32.
>      Just like Elena recently upgraded a test to avoid hard-coded
>      line number, we should probably clean this up, someday. This can
>      be a separate patch, however.
> 
>   b. The program was attached to while inside the busy loop, so the
>      test was expecting the debugger to report that the inferior was
>      inside function main() after the attach command was performed.
>      This is no longer the case, since the inferior is most likely
>      inside a system call, doing the delay. I felt that it was not
>      a necessity to checke where the debugger thought the inferior
>      was stopped, so removed that part of the expected output. What
>      I can do is add an extra test that does a backtrace and verifies
>      that it contains a frame for function main().
> 
> 2003-11-18  J. Brobecker  <brobecker@gnat.com>
> 
>         * gdb.base/attach.c: Add small delay in busy loop.
>         * gdb.base/attach.exp: Make some associated adjustments.
> 
> OK to apply?

Seems to work on Linux.  I'd sure like to see that backtrace test,
though, to confirm that we are able to build a meaningful machine
state after we attach.

Michael

> ------------------------------------------------------------------------
> 
> Index: attach.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/testsuite/gdb.base/attach.c,v
> retrieving revision 1.1.1.1
> diff -u -p -r1.1.1.1 attach.c
> --- attach.c	28 Jun 1999 23:02:40 -0000	1.1.1.1
> +++ attach.c	18 Nov 2003 22:51:12 -0000
> @@ -5,15 +5,28 @@
>     exit unless/until gdb sets the variable to non-zero.)
>     */
>  #include <stdio.h>
> +#include <time.h>
>  
>  int  should_exit = 0;
>  
> +/* Wait for 0.1 sec.  */
> +
> +void
> +small_delay ()
> +{
> +  const struct timespec ts = { 0, 1000000 }; /* 0.1 sec */
> +  nanosleep (&ts, NULL);
> +}
> +
>  int main ()
>  {
>    int  local_i = 0;
>  
>    while (! should_exit)
>      {
> +      /* Insert a small delay in order to avoid consuming all the CPU
> +         while waiting for the debugger to take control.  */
> +      small_delay ();
>        local_i++;
>      }
>    return 0;
> Index: attach.exp
> ===================================================================
> RCS file: /cvs/src/src/gdb/testsuite/gdb.base/attach.exp,v
> retrieving revision 1.12
> diff -u -p -r1.12 attach.exp
> --- attach.exp	7 Aug 2003 17:55:41 -0000	1.12
> +++ attach.exp	18 Nov 2003 22:51:13 -0000
> @@ -173,7 +173,7 @@ proc do_attach_tests {} {
>  
>     send_gdb "attach $testpid\n"
>     gdb_expect {
> -      -re "Attaching to program.*`?$escapedbinfile'?, process $testpid.*main.*at .*$srcfile:.*$gdb_prompt $"\
> +      -re "Attaching to program.*`?$escapedbinfile'?, process $testpid.*$gdb_prompt $"\
>                        {pass "attach1, after setting file"}
>        -re "$gdb_prompt $" {fail "attach1, after setting file"}
>        timeout         {fail "(timeout) attach1, after setting file"}
> @@ -236,7 +236,7 @@ proc do_attach_tests {} {
>     #
>     send_gdb "attach $testpid\n"
>     gdb_expect {
> -      -re "Attaching to process $testpid.*Reading symbols from $escapedbinfile.*main.*at .*$gdb_prompt $"\
> +      -re "Attaching to process $testpid.*Reading symbols from $escapedbinfile.*$gdb_prompt $"\
>                        {pass "attach2"}
>        -re "$gdb_prompt $" {fail "attach2"}
>        timeout         {fail "(timeout) attach2"}
> @@ -253,16 +253,16 @@ proc do_attach_tests {} {
>  
>     # Verify that the modification really happened.
>     #
> -   send_gdb "tbreak 19\n"
> +   send_gdb "tbreak 32\n"
>     gdb_expect {
> -      -re "Breakpoint .*at.*$srcfile, line 19.*$gdb_prompt $"\
> +      -re "Breakpoint .*at.*$srcfile, line 32.*$gdb_prompt $"\
>                        {pass "after attach2, set tbreak postloop"}
>        -re "$gdb_prompt $" {fail "after attach2, set tbreak postloop"}
>        timeout         {fail "(timeout) after attach2, set tbreak postloop"}
>     }
>     send_gdb "continue\n"
>     gdb_expect {
> -      -re "main.*at.*$srcfile:19.*$gdb_prompt $"\
> +      -re "main.*at.*$srcfile:32.*$gdb_prompt $"\
>                        {pass "after attach2, reach tbreak postloop"}
>        -re "$gdb_prompt $" {fail "after attach2, reach tbreak postloop"}
>        timeout         {fail "(timeout) after attach2, reach tbreak postloop"}
> @@ -337,7 +337,7 @@ proc do_attach_tests {} {
>  
>     send_gdb "attach $testpid\n"
>     gdb_expect {
> -      -re "Attaching to process $testpid.*Reading symbols from $escapedbinfile.*main.*at .*$gdb_prompt $"\
> +      -re "Attaching to process $testpid.*Reading symbols from $escapedbinfile.*$gdb_prompt $"\
>                        {pass "attach when process' a.out not in cwd"}
>        -re "$gdb_prompt $" {fail "attach when process' a.out not in cwd"}
>        timeout         {fail "(timeout) attach when process' a.out not in cwd"}