gdb/main: execute breakpoint commands for '-iex' and '-ex' commands

Suppose we have the script file below:

  break main
  commands
    print 123
  end
  run

If started with this script file, GDB executes the breakpoint command:

  $ gdb -q -x myscript --args ./test
  Reading symbols from ./test...
  Breakpoint 1 at 0x114e: file test.c, line 2.

  Breakpoint 1, main () at test.c:2
  2         return 0;
  $1 = 123
  (gdb)

However, if we remove the "run" line from the script and pass it with
the '-ex' option instead, the command is not executed:

  $ gdb -q -x myscript_no_run --args ./test
  Reading symbols from ./test...
  Breakpoint 1 at 0x114e: file test.c, line 2.
  Starting program: /path/to/test

  Breakpoint 1, main () at test.c:2
  2         return 0;
  (gdb)

If the user enters a command at this point, the breakpoint command
is executed, yielding weird output:

  $ gdb -q -x myscript_no_run --args ./test
  Reading symbols from ./test...
  Breakpoint 1 at 0x114e: file test.c, line 2.
  Starting program: /path/to/test

  Breakpoint 1, main () at test.c:2
  2         return 0;
  (gdb) print "a"
  $1 = "a"
  $2 = 123

When consuming script files, GDB runs bp actions after executing a
command.  See `command_handler` in event-top.c:

  if (c[0] != '#')
    {
      execute_command (command, ui->instream == ui->stdin_stream);

      /* Do any commands attached to breakpoint we stopped at.  */
      bpstat_do_actions ();
    }

However, for '-ex' commands, `bpstat_do_actions` is not invoked.
Hence, the misaligned output explained above occurs.  To fix the
problem, add a call to `bpstat_do_actions` after executing a command.

gdb/ChangeLog:
2020-12-07  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* main.c (catch_command_errors): Add a flag parameter; invoke
	`bpstat_do_actions` if the flag is set.
	(execute_cmdargs): Update a call to `catch_command_errors`.

gdb/testsuite/ChangeLog:
2020-12-07  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* gdb.base/bp-cmds-run-with-ex.c: New file.
	* gdb.base/bp-cmds-run-with-ex.exp: New file.
	* gdb.base/bp-cmds-run-with-ex.gdb: New file.
	* gdb.gdb/python-interrupts.exp: Update the call to
	'catch_command_errors' with the new argument.
	* gdb.gdb/python-selftest.exp: Ditto.

1 files changed, 7 insertions, 2 deletions

diff --git a/gdb/main.c b/gdb/main.c
index d3a6637..9d0fad4 100644
--- a/gdb/main.c
+++ b/gdb/main.c
@@ -439,7 +439,8 @@ typedef void (catch_command_errors_const_ftype) (const char *, int);
 
 static int
 catch_command_errors (catch_command_errors_const_ftype command,
-		      const char *arg, int from_tty)
+		      const char *arg, int from_tty,
+		      bool do_bp_actions = false)
 {
   try
     {
@@ -448,6 +449,10 @@ catch_command_errors (catch_command_errors_const_ftype command,
       command (arg, from_tty);
 
       maybe_wait_sync_command_done (was_sync);
+
+      /* Do any commands attached to breakpoint we stopped at.  */
+      if (do_bp_actions)
+	bpstat_do_actions ();
     }
   catch (const gdb_exception &e)
     {
@@ -531,7 +536,7 @@ execute_cmdargs (const std::vector<struct cmdarg> *cmdarg_vec,
 				     !batch_flag);
       else if (cmdarg_p.type == cmd_type)
 	*ret = catch_command_errors (execute_command, cmdarg_p.string,
-				     !batch_flag);
+				     !batch_flag, true);
     }
 }