remote & target_extra_thread_info, use cache w/ qThreadExtraInfo and qP too

The following patch will make "info threads" call target_extra_thread_info
more frequently.  When I looked at the remote implementation, I noticed
that if we're not using qXfer:threads:read, then we'd be increasing the
remote protocol traffic.  This commit prevents that from happening.

Also, it removes a gratuitous local static buffer, which seems good on
its own.

gdb/ChangeLog:
2018-06-29  Pedro Alves  <palves@redhat.com>

	* remote.c (remote_target::extra_thread_info): Delete
	'display_buf' and 'n' locals.  from the cache, regardless of
	packet mechanims is in use.  Use cache for qThreadExtra and qP
	methods too.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 8cce3514c459eba7de9d3873944b5f636bdf495d..2d75bd2ac155e5a1e841485605f7232e3876bedb 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2018-06-29  Pedro Alves  <palves@redhat.com>
+
+       * remote.c (remote_target::extra_thread_info): Delete
+       'display_buf' and 'n' locals.  from the cache, regardless of
+       packet mechanims is in use.  Use cache for qThreadExtra and qP
+       methods too.
+
 2018-06-29  Pedro Alves  <palves@redhat.com>
 
        * blockframe.c (find_pc_sect_containing_function): New function.

diff --git a/gdb/remote.c b/gdb/remote.c
index cf56a5636aa06b7cfefd01d08ebe2be34f0279d3..f88e801dbef1b5c0635afefe1ef7a57be9970656 100644 (file)
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -3830,12 +3830,9 @@ const char *
 remote_target::extra_thread_info (thread_info *tp)
 {
   struct remote_state *rs = get_remote_state ();
-  int result;
   int set;
   threadref id;
   struct gdb_ext_thread_info threadinfo;
-  static char display_buf[100];        /* arbitrary...  */
-  int n = 0;                    /* position in display_buf */
 
   if (rs->remote_desc == 0)            /* paranoia */
     internal_error (__FILE__, __LINE__,
@@ -3847,15 +3844,18 @@ remote_target::extra_thread_info (thread_info *tp)
        server doesn't know about it.  */
     return NULL;
 
+  std::string &extra = get_remote_thread_info (tp)->extra;
+
+  /* If already have cached info, use it.  */
+  if (!extra.empty ())
+    return extra.c_str ();
+
   if (packet_support (PACKET_qXfer_threads) == PACKET_ENABLE)
     {
-      if (tp->priv != NULL)
-       {
-         const std::string &extra = get_remote_thread_info (tp)->extra;
-         return !extra.empty () ? extra.c_str () : NULL;
-       }
-      else
-       return NULL;
+      /* If we're using qXfer:threads:read, then the extra info is
+        included in the XML.  So if we didn't have anything cached,
+        it's because there's really no extra info.  */
+      return NULL;
     }
 
   if (rs->use_threadextra_query)
@@ -3871,10 +3871,9 @@ remote_target::extra_thread_info (thread_info *tp)
       getpkt (&rs->buf, &rs->buf_size, 0);
       if (rs->buf[0] != 0)
        {
-         n = std::min (strlen (rs->buf) / 2, sizeof (display_buf));
-         result = hex2bin (rs->buf, (gdb_byte *) display_buf, n);
-         display_buf [result] = '\0';
-         return display_buf;
+         extra.resize (strlen (rs->buf) / 2);
+         hex2bin (rs->buf, (gdb_byte *) &extra[0], extra.size ());
+         return extra.c_str ();
        }
     }
 
@@ -3887,22 +3886,20 @@ remote_target::extra_thread_info (thread_info *tp)
     if (threadinfo.active)
       {
        if (*threadinfo.shortname)
-         n += xsnprintf (&display_buf[0], sizeof (display_buf) - n,
-                         " Name: %s,", threadinfo.shortname);
+         string_appendf (extra, " Name: %s", threadinfo.shortname);
        if (*threadinfo.display)
-         n += xsnprintf (&display_buf[n], sizeof (display_buf) - n,
-                         " State: %s,", threadinfo.display);
+         {
+           if (!extra.empty ())
+             extra += ',';
+           string_appendf (extra, " State: %s", threadinfo.display);
+         }
        if (*threadinfo.more_display)
-         n += xsnprintf (&display_buf[n], sizeof (display_buf) - n,
-                         " Priority: %s", threadinfo.more_display);
-
-       if (n > 0)
          {
-           /* For purely cosmetic reasons, clear up trailing commas.  */
-           if (',' == display_buf[n-1])
-             display_buf[n-1] = ' ';
-           return display_buf;
+           if (!extra.empty ())
+             extra += ',';
+           string_appendf (extra, " Priority: %s", threadinfo.more_display);
          }
+       return extra.c_str ();
       }
   return NULL;
 }