[PATCHv2 4/9] gdb: build dprintf commands just once in code_breakpoint constructor

[Andrew Burgess <aburgess@redhat.com>]

I noticed in code_breakpoint::code_breakpoint that we are calling
update_dprintf_command_list once for each breakpoint location, when we
really only need to call this once per breakpoint -- the data updated
by this function, the breakpoint command list -- is per breakpoint,
not per breakpoint location.  Calling update_dprintf_command_list
multiple times is just wasted effort, there's no per location error
checking, we don't even pass the current location to the function.

This commit moves the update_dprintf_command_list call outside of the
per-location loop. I have also changes the 'if' that handles the case
where the extra_string (which holds the format/args) is empty.  I
don't believe that this situation can ever arise -- and if it does we
should be catching it earlier and throwing an error at that point.

There should be no user visible changes after this commit.
---
 gdb/breakpoint.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 0827b587d5f..d03c55587be 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -8544,19 +8544,17 @@ code_breakpoint::code_breakpoint (struct gdbarch *gdbarch_,
       /* Do not set breakpoint locations conditions yet.  As locations
 	 are inserted, they get sorted based on their addresses.  Let
 	 the list stabilize to have reliable location numbers.  */
+    }
 
-      /* Dynamic printf requires and uses additional arguments on the
-	 command line, otherwise it's an error.  */
-      if (type == bp_dprintf)
-	{
-	  if (extra_string != nullptr)
-	    update_dprintf_command_list (this);
-	  else
-	    error (_("Format string required"));
-	}
-      else if (extra_string != nullptr)
-	error (_("Garbage '%s' at end of command"), extra_string.get ());
+  /* Dynamic printf requires and uses additional arguments on the
+     command line, otherwise it's an error.  */
+  if (type == bp_dprintf)
+    {
+      gdb_assert (extra_string != nullptr);
+      update_dprintf_command_list (this);
     }
+  else if (extra_string != nullptr)
+    error (_("Garbage '%s' at end of command"), extra_string.get ());
 
   /* The order of the locations is now stable.  Set the location
      condition using the location's number.  */
-- 
2.25.4