2002-01-15 Michael Snyder <msnyder@redhat.com>

	* target.c: New command, "set trust-readonly-sections on".
	(do_xfer_memory): Honor the suggestion to trust readonly sections
	by reading them from the object file instead of from the target.
	(initialize_targets): Register command "set trust-readonly-sections".

1 files changed, 36 insertions, 6 deletions

diff --git a/gdb/target.c b/gdb/target.c
index 1af8883..95ec4ef 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -835,6 +835,8 @@ target_write_memory (CORE_ADDR memaddr, char *myaddr, int len)
   return target_xfer_memory (memaddr, myaddr, len, 1);
 }
 
+static int trust_readonly = 0;
+
 /* Move memory to or from the targets.  The top target gets priority;
    if it cannot handle it, it is offered to the next one down, etc.
 
@@ -857,6 +859,24 @@ do_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
      0.  */
   errno = 0;
 
+  if (!write && trust_readonly)
+    {
+      /* User-settable option, "trust-readonly".  If true, then
+	 memory from any SEC_READONLY bfd section may be read
+	 directly from the bfd file. */
+
+      struct section_table *secp;
+
+      for (secp = current_target.to_sections;
+	   secp < current_target.to_sections_end;
+	   secp++)
+	{
+	  if (memaddr >= secp->addr && memaddr < secp->endaddr)
+	    return xfer_memory (memaddr, myaddr, len, 0, 
+				attrib, &current_target);
+	}
+    }
+
   /* The quick case is that the top target can handle the transfer.  */
   res = current_target.to_xfer_memory
     (memaddr, myaddr, len, write, attrib, &current_target);
@@ -2254,13 +2274,23 @@ initialize_targets (void)
   add_info ("target", target_info, targ_desc);
   add_info ("files", target_info, targ_desc);
 
-  add_show_from_set (
-		add_set_cmd ("target", class_maintenance, var_zinteger,
-			     (char *) &targetdebug,
-			     "Set target debugging.\n\
+  add_show_from_set 
+    (add_set_cmd ("target", class_maintenance, var_zinteger,
+		  (char *) &targetdebug,
+		  "Set target debugging.\n\
 When non-zero, target debugging is enabled.", &setdebuglist),
-		      &showdebuglist);
-
+     &showdebuglist);
+
+  add_show_from_set 
+    (add_set_boolean_cmd 
+     ("trust-readonly-sections", class_support, 
+      &trust_readonly, 
+      "Set mode for reading from readonly sections.\n\
+When this mode is on, memory reads from readonly sections (such as .text)\n\
+will be read from the object file instead of from the target.  This will\n\
+result in significant performance improvement for remote targets.",
+      &setlist),
+     &showlist);
 
   add_com ("monitor", class_obscure, do_monitor_command,
 	   "Send a command to the remote monitor (remote targets only).");