Re: [PATCH] fix PR 15180 "May only run agent-printf on the target"

[Hui Zhu <teawater@gmail.com>]

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On Mon, Jul 1, 2013 at 4:10 PM, Pedro Alves <palves@redhat.com> wrote:
> On 06/30/2013 04:17 PM, Hui Zhu wrote:
>>> > If dprintf style is agent, then the target doesn't report events
>>> > for such hits.  If we happen to see a trap reported for the
>>> > same address as another breakpoint, the trap is surely not explained
>>> > by the dprintf.  IOW, we shouldn't have a bpstat a dprintf w/ style
>>> > agent at all.  What is need is to override the breakpoint_hit method
>>> > of dprintf_breakpoint_ops to always return false for agent style dprintfs.
>>> >
>>> > Or maybe I'm missing something.  I have a hard time going from
>>> > the bug description in the PR to the patch.
>> OK.  I add dprintf_check_status in the new patch according to your comments.
>>
>
> But I suggested the breakpoint_ops->breakpoint_hit not breakpoint_ops->check_status.
> An agent-style dprintf is just like a tracepoint.  It can't ever explain
> a stop.  See tracepoint_breakpoint_hit.  If it didn't work, please explain why.

OK.  Post a new version according to your comments.
Please help me review it.

Thanks,
Hui

>
> --
> Pedro Alves
>

2013-07-01  Hui Zhu  <hui@codesourcery.com>

	PR gdb/15180
	* breakpoint.c (dprintf_breakpoint_hit): New function.
	(initialize_breakpoint_ops): Set dprintf_breakpoint_hit.

2013-07-01  Hui Zhu  <hui@codesourcery.com>

	PR gdb/15180
	* gdb.base/dprintf-same-addr.c: New file.
	* gdb.base/dprintf-same-addr.exp: New file.

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--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -13389,6 +13389,19 @@ tracepoint_probe_decode_linespec (struct
 
 static struct breakpoint_ops tracepoint_probe_breakpoint_ops;
 
+/* Implement the "breakpoint_hit" breakpoint_ops method for dprintf.  */
+
+static int
+dprintf_breakpoint_hit (const struct bp_location *bl,
+			struct address_space *aspace, CORE_ADDR bp_addr,
+			const struct target_waitstatus *ws)
+{
+  if (strcmp (dprintf_style, dprintf_style_agent) != 0)
+    return bkpt_breakpoint_hit (bl, aspace, bp_addr, ws);
+
+  return 0;
+}
+
 /* Dprintf breakpoint_ops methods.  */
 
 static void
@@ -15957,6 +15970,7 @@ initialize_breakpoint_ops (void)
 
   ops = &dprintf_breakpoint_ops;
   *ops = bkpt_base_breakpoint_ops;
+  ops->breakpoint_hit = dprintf_breakpoint_hit;
   ops->re_set = dprintf_re_set;
   ops->resources_needed = bkpt_resources_needed;
   ops->print_it = bkpt_print_it;

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--- /dev/null
+++ b/gdb/testsuite/gdb.base/dprintf-same-addr.c
@@ -0,0 +1,35 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   Contributed by Hui Zhu  <hui@codesourcery.com>
+
+   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 <stdio.h>
+
+int
+main ()
+{
+  int i;
+
+  for (i=0; i < 99; i++)
+    {
+      printf("Hello\n");	/* test line  */
+
+      /* Without this line, test with fprintf will not work.  */
+      fprintf (stderr, "world\n");
+    }
+
+  return 0;
+}
--- /dev/null
+++ b/gdb/testsuite/gdb.base/dprintf-same-addr.exp
@@ -0,0 +1,82 @@
+#   Copyright (C) 2013 Free Software Foundation, Inc.
+#   Contributed by Hui Zhu  <hui@codesourcery.com>
+
+# 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 for dprintf with non-stop" \
+    ${testfile} ${srcfile} {debug}] {
+    return -1
+}
+
+set bp_location [gdb_get_line_number "test line"]
+
+proc continue_dprintf {args} {
+    with_test_prefix $args {
+	global bp_location
+
+	gdb_test "dprintf $bp_location,\"Hello\\n\"" "Dprintf .*"
+	gdb_test_no_output {set $bpnum1=$bpnum}
+	gdb_breakpoint $bp_location
+	gdb_test_no_output {set $bpnum2=$bpnum}
+
+	gdb_test "continue" "Breakpoint \[0-9\]+, main .*" "First continue"
+
+	gdb_test_no_output "condition \$bpnum1 i>10"
+	gdb_test_no_output "condition \$bpnum2 i>15"
+
+	gdb_test "continue" "Breakpoint \[0-9\]+, main .*" "Second continue"
+
+	gdb_test "p i" "\[0-9\]+ = 16" "check i"
+    }
+}
+
+if ![runto main] {
+    return -1
+}
+gdb_test_no_output "set dprintf-style gdb" "Set dprintf style to gdb"
+continue_dprintf "gdb"
+
+if ![target_info exists gdb,noinferiorio] {
+    if ![runto main] {
+	return -1
+    }
+    gdb_test_no_output "set dprintf-style call" "Set dprintf style to call"
+    continue_dprintf "call"
+
+    if ![runto main] {
+	return -1
+    }
+    gdb_test_no_output "set dprintf-function fprintf" "set dprintf-channel stderr"
+    gdb_test_no_output "set dprintf-channel stderr" "set dprintf channel"
+    continue_dprintf "fprintf"
+} else {
+    unsupported "test dprintf-style call"
+}
+
+if ![runto main] {
+    return -1
+}
+gdb_test "dprintf main,\"Hello\\n\"" "Dprintf .*"
+set msg "Set dprintf style to agent"
+gdb_test_multiple "set dprintf-style agent" $msg {
+    -re "warning: Target cannot run dprintf commands.*\r\n$gdb_prompt $" {
+	unsupported $msg
+    }
+    -re ".*$gdb_prompt $" {
+	pass $msg
+	continue_dprintf "agent"
+    }
+}