Re: [patch] Add "debug jit" for easier tracing of JIT support internals

[Paul Pluzhnikov <ppluzhnikov@google.com>]

[-- Attachment #1: Type: text/plain, Size: 905 bytes --]

On Wed, Jan 5, 2011 at 12:01 PM, Doug Evans <dje@google.com> wrote:

> I'd suggest removing "Higher numbers are more verbose."

Done.

> and while I haven't tried it, I wonder if show_jit_debug is necessary

It's not.

On Wed, Jan 5, 2011 at 12:57 PM, Eli Zaretskii <eliz@gnu.org> wrote:


>>       (_initialize_jit): Register "debug jit" command.
>
> Since this is user-level setting, it should be in the manual.

Done.


One question: is '%zu' appropriate format for printing size_t ?


Thanks,

-- 
Paul Pluzhnikov


ChangeLog:

2010-01-05  Paul Pluzhnikov  <ppluzhnikov@google.com>

	* jit.c (jit_debug): New variable.
	(jit_register_code, jit_inferior_init): Add debug output.
	(_initialize_jit): Register "debug jit" command.


doc/ChangeLog:

2010-01-05  Paul Pluzhnikov  <ppluzhnikov@google.com>

	* gdb.texi (Debugging Output): Document "set debug jit"

[-- Attachment #2: gdb-jit-debug-20110105-2.txt --]
[-- Type: text/plain, Size: 3890 bytes --]

Index: jit.c
===================================================================
RCS file: /cvs/src/src/gdb/jit.c,v
retrieving revision 1.8
diff -u -p -r1.8 jit.c
--- jit.c	1 Jan 2011 15:33:09 -0000	1.8
+++ jit.c	5 Jan 2011 21:46:10 -0000
@@ -21,6 +21,8 @@
 
 #include "jit.h"
 #include "breakpoint.h"
+#include "command.h"
+#include "gdbcmd.h"
 #include "gdbcore.h"
 #include "observer.h"
 #include "objfiles.h"
@@ -48,6 +50,10 @@ static CORE_ADDR jit_descriptor_addr = 0
 
 static int registering_code = 0;
 
+/* Non-zero if we want to see trace of jit level stuff.  */
+
+static int jit_debug = 0;
+
 /* Helper cleanup function to clear an integer flag like the one above.  */
 
 static void
@@ -219,6 +225,13 @@ jit_register_code (struct gdbarch *gdbar
   const struct bfd_arch_info *b;
   CORE_ADDR *entry_addr_ptr;
 
+  if (jit_debug)
+    fprintf_unfiltered (gdb_stdlog,
+			"jit_register_code, symfile_addr = %s, "
+			"symfile_size = %zu\n",
+			paddress (gdbarch, code_entry->symfile_addr),
+			code_entry->symfile_size);
+
   nbfd = bfd_open_from_target_memory (code_entry->symfile_addr,
                                       code_entry->symfile_size, gnutarget);
   old_cleanups = make_cleanup_bfd_close (nbfd);
@@ -314,6 +327,11 @@ jit_inferior_init (struct gdbarch *gdbar
   struct jit_code_entry cur_entry;
   CORE_ADDR cur_entry_addr;
 
+  if (jit_debug)
+    fprintf_unfiltered (gdb_stdlog,
+			"jit_inferior_init, registering_code = %d\n",
+			registering_code);
+
   /* When we register code, GDB resets its breakpoints in case symbols have
      changed.  That in turn calls this handler, which makes us look for new
      code again.  To avoid being re-entered, we check this flag.  */
@@ -329,6 +347,10 @@ jit_inferior_init (struct gdbarch *gdbar
   if (reg_addr == 0)
     return;
 
+  if (jit_debug)
+    fprintf_unfiltered (gdb_stdlog, "jit_inferior_init, reg_addr = %s\n",
+			paddress (gdbarch, reg_addr));
+
   /* Lookup the descriptor symbol and cache the addr.  If it is missing, we
      assume we are not attached to a JIT and return early.  */
   desc_symbol = lookup_minimal_symbol (jit_descriptor_name, NULL, NULL);
@@ -338,6 +360,11 @@ jit_inferior_init (struct gdbarch *gdbar
   if (jit_descriptor_addr == 0)
     return;
 
+  if (jit_debug)
+    fprintf_unfiltered (gdb_stdlog,
+			"jit_inferior_init, jit_descriptor_addr = %s\n",
+			paddress (gdbarch, jit_descriptor_addr));
+
   /* Read the descriptor so we can check the version number and load any already
      JITed functions.  */
   jit_read_descriptor (gdbarch, &descriptor);
@@ -453,6 +480,13 @@ extern void _initialize_jit (void);
 void
 _initialize_jit (void)
 {
+  add_setshow_zinteger_cmd ("jit", class_maintenance, &jit_debug, _("\
+Set JIT debugging."), _("\
+Show JIT debugging."), _("\
+When non-zero, JIT debugging is enabled."),
+			    NULL, NULL,
+			    &setdebuglist, &showdebuglist);
+
   observer_attach_inferior_created (jit_inferior_created_observer);
   observer_attach_inferior_exit (jit_inferior_exit_hook);
   jit_objfile_data = register_objfile_data ();
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.783
diff -u -p -r1.783 gdb.texinfo
--- doc/gdb.texinfo	5 Jan 2011 05:09:52 -0000	1.783
+++ doc/gdb.texinfo	5 Jan 2011 21:46:11 -0000
@@ -19955,6 +19955,11 @@ The default is off.  @file{infrun.c} con
 for implementing operations such as single-stepping the inferior.
 @item show debug infrun
 Displays the current state of @value{GDBN} inferior debugging.
+@item set debug jit
+@cindex just-in-time compilation
+Turns on or off debugging messages from JIT debug support.
+@item show debug jit
+Displays the current state of @value{GDBN} JIT debugging.
 @item set debug lin-lwp
 @cindex @sc{gnu}/Linux LWP debug messages
 @cindex Linux lightweight processes