[binutils-gdb] Don't read agent symbols when disabled

[binutils-gdb] Don't read agent symbols when disabled

[Christian Biesinger]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=8d6efaa20d9b44cc016ae0f55aeceabcfe7d4e68

commit 8d6efaa20d9b44cc016ae0f55aeceabcfe7d4e68
Author: Christian Biesinger <cbiesinger@google.com>
Date:   Wed Oct 30 19:10:13 2019 -0500

    Don't read agent symbols when disabled
    
    This avoids unnecessary work, and becomes important with the patch in
    https://sourceware.org/ml/gdb-patches/2019-10/msg01143.html
    
    gdb/ChangeLog:
    
    2019-10-31  Christian Biesinger  <cbiesinger@google.com>
    
    	* agent.c (set_can_use_agent): When the setting is turned on,
    	look up agent symbols if we don't have them yet.
    	(agent_new_objfile): Don't look up agent symbols when the agent
    	setting is off.
    
    Change-Id: I6523a5640c95d38299998050a6c620e51096e8ed

Diff:
---
 gdb/ChangeLog |  7 +++++++
 gdb/agent.c   | 19 +++++++++++++++----
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index cdc44bc..3c26e6d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,12 @@
 2019-10-31  Christian Biesinger  <cbiesinger@google.com>
 
+	* agent.c (set_can_use_agent): When the setting is turned on,
+	look up agent symbols if we don't have them yet.
+	(agent_new_objfile): Don't look up agent symbols when the agent
+	setting is off.
+
+2019-10-31  Christian Biesinger  <cbiesinger@google.com>
+
 	* config.in: Regenerate.
 
 2019-10-31  Christian Biesinger  <cbiesinger@google.com>
diff --git a/gdb/agent.c b/gdb/agent.c
index bc71860..da251a3 100644
--- a/gdb/agent.c
+++ b/gdb/agent.c
@@ -20,6 +20,8 @@
 #include "gdbcmd.h"
 #include "target.h"
 #include "gdbsupport/agent.h"
+#include "observable.h"
+#include "objfiles.h"
 
 /* Enum strings for "set|show agent".  */
 
@@ -46,20 +48,29 @@ show_can_use_agent (struct ui_file *file, int from_tty,
 static void
 set_can_use_agent (const char *args, int from_tty, struct cmd_list_element *c)
 {
-  if (target_use_agent (can_use_agent == can_use_agent_on) == 0)
+  bool can_use = (can_use_agent == can_use_agent_on);
+  if (can_use && !agent_loaded_p ())
+    {
+      /* Since the setting was off, we may not have observed the objfiles and
+         therefore not looked up the required symbols.  Do so now.  */
+      for (objfile *objfile : current_program_space->objfiles ())
+	if (agent_look_up_symbols (objfile) == 0)
+	  break;
+    }
+  if (target_use_agent (can_use) == 0)
     /* Something wrong during setting, set flag to default value.  */
     can_use_agent = can_use_agent_off;
 }
 
-#include "observable.h"
-#include "objfiles.h"
-
 static void
 agent_new_objfile (struct objfile *objfile)
 {
   if (objfile == NULL || agent_loaded_p ())
     return;
 
+  if (can_use_agent == can_use_agent_off)
+    return;
+
   agent_look_up_symbols (objfile);
 }