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.

2 files changed, 247 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.trace/ftrace.c b/gdb/testsuite/gdb.trace/ftrace.c
new file mode 100644
index 0000000..a7d008d
--- /dev/null
+++ b/gdb/testsuite/gdb.trace/ftrace.c
@@ -0,0 +1,76 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2011 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef SYMBOL_PREFIX
+#define SYMBOL(str)     SYMBOL_PREFIX #str
+#else
+#define SYMBOL(str)     #str
+#endif
+
+int globvar;
+
+static void
+begin (void)
+{}
+
+/* Called from asm.  */
+static void __attribute__((used))
+func (void)
+{}
+
+static void
+marker (int anarg)
+{
+  /* `set_point' is the label at which to set a fast tracepoint.  The
+     insn at the label must be large enough to fit a fast tracepoint
+     jump.  */
+  asm ("    .global " SYMBOL(set_point) "\n"
+       SYMBOL(set_point) ":\n"
+#if (defined __x86_64__ || defined __i386__)
+       "    call " SYMBOL(func) "\n"
+#endif
+       );
+
+  ++anarg;
+
+  /* Set up a known 4-byte instruction so we can try to set a shorter
+     fast tracepoint at it.  */
+  asm ("    .global " SYMBOL(four_byter) "\n"
+       SYMBOL(four_byter) ":\n"
+#if (defined __i386__)
+       "    cmpl $0x1,0x8(%ebp) \n"
+#endif
+       );
+}
+
+static void
+end (void)
+{}
+
+int
+main ()
+{
+  begin ();
+
+  for (globvar = 1; globvar < 11; ++globvar)
+    {
+      marker (globvar * 100);
+    }
+
+  end ();
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.trace/ftrace.exp b/gdb/testsuite/gdb.trace/ftrace.exp
new file mode 100644
index 0000000..f45c6da
--- /dev/null
+++ b/gdb/testsuite/gdb.trace/ftrace.exp
@@ -0,0 +1,171 @@
+# Copyright 2011 Free Software Foundation, Inc.
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+load_lib "trace-support.exp";
+
+set testfile "ftrace"
+set executable $testfile
+set srcfile $testfile.c
+set binfile $objdir/$subdir/$testfile
+set expfile $testfile.exp
+
+# Some targets have leading underscores on assembly symbols.
+set additional_flags [gdb_target_symbol_prefix_flags]
+
+if [prepare_for_testing $expfile $executable $srcfile \
+	[list debug $additional_flags]] {
+    untested "failed to prepare for trace tests"
+    return -1
+}
+
+if ![runto_main] {
+    fail "Can't run to main to check for trace support"
+    return -1
+}
+
+if ![gdb_target_supports_trace] {
+    unsupported "target does not support trace"
+    return -1
+}
+
+set libipa $objdir/../gdbserver/libinproctrace.so
+gdb_load_shlibs $libipa
+
+# Can't use prepare_for_testing, because that splits compiling into
+# building objects and then linking, and we'd fail with "linker input
+# file unused because linking not done" when building the object.
+
+if { [gdb_compile "$srcdir/$subdir/$srcfile" $binfile \
+	  executable [list debug $additional_flags shlib=$libipa] ] != "" } {
+    untested "failed to compile ftrace tests"
+    return -1
+}
+clean_restart ${executable}
+
+if ![runto_main] {
+    fail "Can't run to main for ftrace tests"
+    return 0
+}
+
+proc run_trace_experiment {} {
+
+    gdb_test "continue" \
+	".*Breakpoint \[0-9\]+, begin .*" \
+	"advance to trace begin"
+
+    gdb_test_no_output "tstart" "start trace experiment"
+
+    gdb_test "continue" \
+	".*Breakpoint \[0-9\]+, end .*" \
+	"advance through tracing"
+
+    gdb_test "tstatus" ".*Trace .*" "check on trace status"
+
+    gdb_test "tstop" "" ""
+}
+
+proc test_fast_tracepoints {} {
+
+    set fourgood 0
+
+    gdb_test "break begin" ".*" ""
+
+    gdb_test "break end" ".*" ""
+
+    gdb_test "print gdb_agent_gdb_trampoline_buffer_error" ".*" ""
+
+    if { [is_x86_like_target] } {
+
+	gdb_test "ftrace set_point" "Fast tracepoint .*" \
+	    "fast tracepoint at a long insn"
+
+	gdb_trace_setactions "collect at set_point: define actions" \
+	    "" \
+	    "collect globvar, anarg" "^$"
+
+	# Make a test of shorter fast tracepoints, 32-bit x86 only
+
+	if { [istarget "i?86-*-*"] } {
+
+	    # A Linux target needs to be able to allocate trampolines in the
+	    # 16-bit range, check mmap_min_addr so we can warn testers.
+	    if { [istarget "i?86-*-linux*"] } {
+
+		set minaddr [exec sh -c "cat /proc/sys/vm/mmap_min_addr"]
+
+		if { [expr $minaddr > 64512] } {
+		    warning "mmap_min_addr > 64512, fast tracepoint will fail"
+		    warning "do \"sudo sysctl -w vm.mmap_min_addr=32768\" to adjust"
+		}
+	    }
+
+	    gdb_test_multiple "ftrace four_byter" "set 4-byte fast tracepoint" {
+		-re "May not have a fast tracepoint at .*" {
+		    pass "4-byte fast tracepoint could not be set"
+		}
+		-re "Fast tracepoint .*" {
+		    pass "4-byte fast tracepoint is set"
+		    set fourgood 1
+		}
+	    }
+
+	    if { $fourgood } {
+
+		gdb_trace_setactions "collect at four_byter: define actions" \
+		"" \
+		"collect globvar, anarg" "^$"
+	    }
+	}
+
+	run_trace_experiment
+
+	gdb_test "tfind pc *set_point" "Found trace frame .*" \
+	    "tfind set_point frame, first time"
+
+	gdb_test "print globvar" " = 1"
+
+	gdb_test "tfind pc *set_point" "Found trace frame .*" \
+	    "tfind set_point frame, second time"
+
+	gdb_test "print anarg" " = 200"
+
+	gdb_test "tfind start" "Found trace frame .*" \
+	    "reset tfinding"
+
+	if { $fourgood } {
+
+	    gdb_test "tfind pc *four_byter" "Found trace frame .*" \
+		"tfind four_byter frame, first time"
+
+	    gdb_test "print anarg" " = 101" \
+		"look at collected local, first time"
+
+	    gdb_test "tfind pc *four_byter" "Found trace frame .*" \
+		"tfind four_byter frame, second time"
+
+	    gdb_test "print anarg" " = 201" \
+		"look at collected local, second time"
+
+	}
+    }
+}
+
+gdb_reinitialize_dir $srcdir/$subdir
+
+if { [gdb_test "info sharedlibrary" ".*libinproctrace\.so.*" "IPA loaded"] != 0 } {
+    untested "Could not find IPA lib loaded"
+    return 1
+}
+
+test_fast_tracepoints