2011-11-14 Stan Shebs <stan@codesourcery.com>

	    Kwok Cheung Yeung  <kcy@codesourcery.com>

	* NEWS: Document shorter fast tracepoints and qTMinFTPILen packet.
	* i386-tdep.c (i386_fast_tracepoint_valid_at): Query target for
	the minimum instruction size for fast tracepoints.
	* target.h (struct target_ops): Add new method
	to_get_min_fast_tracepoint_insn_len.
	(target_get_min_fast_tracepoint_insn_len): New.
	* target.c (update_current_target): Set up new target operation.
	* remote.c (remote_write_bytes_aux): Fix typo.
	(remote_get_min_fast_tracepoint_insn_len): New.
	(init_remote_ops): Initialize new field.

	* gdb.texinfo (Create and Delete Tracepoints): Describe what is
	needed to get shorter fast tracepoints.
	(Tracepoint Packets): Document new qTMinFTPILen packet.

	* linux-x86-low.c (small_jump_insn): New.
	(i386_install_fast_tracepoint_jump_pad): Add arguments for
	trampoline and error message, build a trampoline and issue a small
	jump instruction to it.
	(x86_install_fast_tracepoint_jump_pad): Add arguments for
	trampoline and error message.
	(x86_get_min_fast_tracepoint_insn_len): New.
	(the_low_target): Add call to x86_get_min_fast_tracepoint_insn_len.
	* linux-low.h (struct linux_target_ops): Add arguments to
	install_fast_tracepoint_jump_pad operation, add new operation.
	* linux-low.c (linux_install_fast_tracepoint_jump_pad): Add
	arguments.
	(linux_get_min_fast_tracepoint_insn_len): New function.
	(linux_target_op): Add new operation.
	* tracepoint.c (gdb_trampoline_buffer): New IPA variable.
	(gdb_trampoline_buffer_end): Ditto.
	(gdb_trampoline_buffer_error): Ditto.
	(struct ipa_sym_addresses): Add fields for new IPA variables.
	(symbol_list): Add entries for new IPA variables.
	(struct tracepoint): Add fields to hold the address range of the
	trampoline used by the tracepoint.
	(trampoline_buffer_head): New static variable.
	(trampoline_buffer_tail): Ditto.
	(claim_trampoline_space): New function.
	(have_fast_tracepoint_trampoline_buffer): New function.
	(clone_fast_tracepoint): Fill in trampoline fields of tracepoint
	structure.
	(install_fast_tracepoint): Ditto, also add error buffer argument.
	(cmd_qtminftpilen): New function.
	(handle_tracepoint_query): Add response to qTMinFTPILen packet.
	(fast_tracepoint_from_trampoline_address): New function.
	(fast_tracepoint_collecting): Handle trampoline as part of jump
	pad space.
	(set_trampoline_buffer_space): New function.
	(initialize_tracepoint): Initialize new IPA variables.
	* target.h (struct target_ops): Add arguments to
	install_fast_tracepoint_jump_pad operation, add new
	get_min_fast_tracepoint_insn_len operation.
	(target_get_min_fast_tracepoint_insn_len): New.
	(install_fast_tracepoint_jump_pad): Add arguments.
	* server.h (IPA_BUFSIZ): Define.
	* linux-i386-ipa.c: Include extra header files.
	(initialize_fast_tracepoint_trampoline_buffer): New function.
	(initialize_low_tracepoint): Call it.
	* server.h (set_trampoline_buffer_space): Declare.
	(claim_trampoline_space): Ditto.
	(have_fast_tracepoint_trampoline_buffer): Ditto.

	* gdb.trace/ftrace.c: New.
	* gdb.trace/ftrace.exp: New.

1 files changed, 29 insertions, 9 deletions

diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index f60e0a6..8a25476 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -359,20 +359,26 @@ struct target_ops
      pad lock object.  ORIG_SIZE is the size in bytes of the
      instruction at TPADDR.  JUMP_ENTRY points to the address of the
      jump pad entry, and on return holds the address past the end of
-     the created jump pad. JJUMP_PAD_INSN is a buffer containing a
-     copy of the instruction at TPADDR.  ADJUST_INSN_ADDR and
-     ADJUST_INSN_ADDR_END are output parameters that return the
-     address range where the instruction at TPADDR was relocated
-     to.  */
+     the created jump pad.  If a trampoline is created by the function,
+     then TRAMPOLINE and TRAMPOLINE_SIZE return the address and size of
+     the trampoline, else they remain unchanged.  JJUMP_PAD_INSN is a
+     buffer containing a copy of the instruction at TPADDR.
+     ADJUST_INSN_ADDR and ADJUST_INSN_ADDR_END are output parameters that
+     return the address range where the instruction at TPADDR was relocated
+     to.  If an error occurs, the ERR may be used to pass on an error
+     message.  */
   int (*install_fast_tracepoint_jump_pad) (CORE_ADDR tpoint, CORE_ADDR tpaddr,
 					   CORE_ADDR collector,
 					   CORE_ADDR lockaddr,
 					   ULONGEST orig_size,
 					   CORE_ADDR *jump_entry,
+					   CORE_ADDR *trampoline,
+					   ULONGEST *trampoline_size,
 					   unsigned char *jjump_pad_insn,
 					   ULONGEST *jjump_pad_insn_size,
 					   CORE_ADDR *adjusted_insn_addr,
-					   CORE_ADDR *adjusted_insn_addr_end);
+					   CORE_ADDR *adjusted_insn_addr_end,
+					   char *err);
 
   /* Return the bytecode operations vector for the current inferior.
      Returns NULL if bytecode compilation is not supported.  */
@@ -380,6 +386,10 @@ struct target_ops
 
   /* Returns true if the target supports disabling randomization.  */
   int (*supports_disable_randomization) (void);
+
+  /* Return the minimum length of an instruction that can be safely overwritten
+     for use as a fast tracepoint.  */
+  int (*get_min_fast_tracepoint_insn_len) (void);
 };
 
 extern struct target_ops *the_target;
@@ -437,6 +447,10 @@ void set_target_ops (struct target_ops *);
 #define target_supports_fast_tracepoints()		\
   (the_target->install_fast_tracepoint_jump_pad != NULL)
 
+#define target_get_min_fast_tracepoint_insn_len()	\
+  (the_target->get_min_fast_tracepoint_insn_len		\
+   ? (*the_target->get_min_fast_tracepoint_insn_len) () : 0)
+
 #define thread_stopped(thread) \
   (*the_target->thread_stopped) (thread)
 
@@ -471,17 +485,23 @@ void set_target_ops (struct target_ops *);
 #define install_fast_tracepoint_jump_pad(tpoint, tpaddr,		\
 					 collector, lockaddr,		\
 					 orig_size,			\
-					 jump_entry, jjump_pad_insn,	\
+					 jump_entry,			\
+					 trampoline, trampoline_size,	\
+					 jjump_pad_insn,		\
 					 jjump_pad_insn_size,		\
 					 adjusted_insn_addr,		\
-					 adjusted_insn_addr_end)	\
+					 adjusted_insn_addr_end,	\
+					 err)				\
   (*the_target->install_fast_tracepoint_jump_pad) (tpoint, tpaddr,	\
 						   collector,lockaddr,	\
 						   orig_size, jump_entry, \
+						   trampoline,		\
+						   trampoline_size,	\
 						   jjump_pad_insn,	\
 						   jjump_pad_insn_size, \
 						   adjusted_insn_addr,	\
-						   adjusted_insn_addr_end)
+						   adjusted_insn_addr_end, \
+						   err)
 
 #define target_emit_ops() \
   (the_target->emit_ops ? (*the_target->emit_ops) () : NULL)