gdb/

	Conditional tracepoints.
	* ax-gdb.h (gen_eval_for_expr): Declare.
	* ax-gdb.c (gen_expr): Generate bytecodes for BINOP_EQUAL
	and other comparisons.
	(gen_eval_for_expr): New function.
	(agent_eval_command): New maintenance command.
	(_initialize_ax_gdb): Define the command.
	* remote.c (struct remote_state): New field cond_tracepoints.
	(PACKET_ConditionalTracepoints): New packet config type.
	(remote_cond_tracepoint_feature): New function.
	(remote_protocol_features): Add ConditionalTracepoints.
	(remote_supports_cond_tracepoints): New function.
	(_initialize_remote): Add ConditionalTracepoints.
	* tracepoint.c (download_tracepoint): Add conditional.
	* NEWS: Mention conditional tracepoints.

	gdb/doc/
	* gdb.texinfo (Tracepoint Conditions): New section.
	(General Query Packets): Describe ConditionalTracepoints.
	(Tracepoint Packets): Describe condition field.
	(Maintenance Commands): Describe maint agent-eval.
	* agentexpr.texi (Using Agent Expressions): Mention eval usage.

	gdb/testsuite/
	* gdb.trace/tracecmd.exp: Add basic test of tracepoint conditions.

1 files changed, 15 insertions, 5 deletions

diff --git a/gdb/doc/agentexpr.texi b/gdb/doc/agentexpr.texi
index 1b893d5..3066319 100644
--- a/gdb/doc/agentexpr.texi
+++ b/gdb/doc/agentexpr.texi
@@ -7,13 +7,11 @@
 
 @c This file is part of the GDB manual.
 @c
-@c Copyright (C) 2003, 2004, 2005, 2006
+@c Copyright (C) 2003, 2004, 2005, 2006, 2009
 @c               Free Software Foundation, Inc.
 @c
 @c See the file gdb.texinfo for copying conditions.
 
-@c Revision: $Id$
-
 @node Agent Expressions
 @appendix The GDB Agent Expression Mechanism
 
@@ -473,8 +471,20 @@ address, and the top of the stack is the lvalue's size, in bytes.
 @node Using Agent Expressions
 @section Using Agent Expressions
 
-Here is a sketch of a full non-stop debugging cycle, showing how agent
-expressions fit into the process.
+Agent expressions can be used in several different ways by @value{GDBN},
+and the debugger can generate different bytecode sequences as appropriate.
+
+One possibility is to do expression evaluation on the target rather
+than the host, such as for the conditional of a conditional
+tracepoint.  In such a case, @value{GDBN} compiles the source
+expression into a bytecode sequence that simply gets values from
+registers or memory, does arithmetic, and returns a result.
+
+Another way to use agent expressions is for tracepoint data
+collection.  @value{GDBN} generates a different bytecode sequence for
+collection; in addition to bytecodes that do the calculation,
+@value{GDBN} adds @code{trace} bytecodes to save the pieces of
+memory that were used.
 
 @itemize @bullet