+2012-04-27 Sergio Durigan Junior <sergiodj@redhat.com>
+ Tom Tromey <tromey@redhat.com>
+
+ * gdb.texinfo (Static Probe Points): New entry, explaining SystemTap
+ and generic static probe support on GDB.
+
2012-04-25 Doug Evans <dje@google.com>
* gdb.texinfo (Go): Fix thinko.
* Conditions:: Break conditions
* Break Commands:: Breakpoint command lists
* Save Breakpoints:: How to save breakpoints in a file
+* Static Probe Points:: Listing static probe points
* Error in Breakpoints:: ``Cannot insert breakpoints''
* Breakpoint-related Warnings:: ``Breakpoint address adjusted...''
@end menu
that can no longer be recreated.
@end table
+@node Static Probe Points
+@subsection Static Probe Points
+
+@cindex static probe point, SystemTap
+@value{GDBN} supports @dfn{SDT} probes in the code. @acronym{SDT} stands
+for Statically Defined Tracing, and the probes are designed to have a tiny
+runtime code and data footprint, and no dynamic relocations. They are
+usable from assembly, C and C@t{++} languages. See
+@uref{http://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation}
+for a good reference on how the @acronym{SDT} probes are implemented.
+
+Currently, @code{SystemTap} (@uref{http://sourceware.org/systemtap/})
+@acronym{SDT} probes are supported on ELF-compatible systems. See
+@uref{http://sourceware.org/systemtap/wiki/AddingUserSpaceProbingToApps}
+for more information on how to add @code{SystemTap} @acronym{SDT} probes
+in your applications.
+
+@cindex semaphores on static probe points
+Some probes have an associated semaphore variable; for instance, this
+happens automatically if you defined your probe using a DTrace-style
+@file{.d} file. If your probe has a semaphore, @value{GDBN} will
+automatically enable it when you specify a breakpoint using the
+@samp{-probe-stap} notation. But, if you put a breakpoint at a probe's
+location by some other method (e.g., @code{break file:line}), then
+@value{GDBN} will not automatically set the semaphore.
+
+You can examine the available static static probes using @code{info
+probes}, with optional arguments:
+
+@table @code
+@kindex info probes
+@item info probes stap @r{[}@var{provider} @r{[}@var{name} @r{[}@var{objfile}@r{]}@r{]}@r{]}
+If given, @var{provider} is a regular expression used to match against provider
+names when selecting which probes to list. If omitted, probes by all
+probes from all providers are listed.
+
+If given, @var{name} is a regular expression to match against probe names
+when selecting which probes to list. If omitted, probe names are not
+considered when deciding whether to display them.
+
+If given, @var{objfile} is a regular expression used to select which
+object files (executable or shared libraries) to examine. If not
+given, all object files are considered.
+
+@item info probes all
+List the available static probes, from all types.
+@end table
+
+@vindex $_probe_arg@r{, convenience variable}
+A probe may specify up to twelve arguments. These are available at the
+point at which the probe is defined---that is, when the current PC is
+at the probe's location. The arguments are available using the
+convenience variables (@pxref{Convenience Vars})
+@code{$_probe_arg0}@dots{}@code{$_probe_arg11}. Each probe argument is
+an integer of the appropriate size; types are not preserved. The
+convenience variable @code{$_probe_argc} holds the number of arguments
+at the current probe point.
+
+These variables are always available, but attempts to access them at
+any location other than a probe point will cause @value{GDBN} to give
+an error message.
+
+
@c @ifclear BARETARGET
@node Error in Breakpoints
@subsection ``Cannot insert breakpoints''
functions with identical names in different source files.
@end table
+@cindex breakpoint at static probe point
+@item -pstap|-probe-stap @r{[}@var{objfile}:@r{[}@var{provider}:@r{]}@r{]}@var{name}
+The @sc{gnu}/Linux tool @code{SystemTap} provides a way for
+applications to embed static probes. @xref{Static Probe Points}, for more
+information on finding and using static probes. This form of linespec
+specifies the location of such a static probe.
+
+If @var{objfile} is given, only probes coming from that shared library
+or executable matching @var{objfile} as a regular expression are considered.
+If @var{provider} is given, then only probes from that provider are considered.
+If several probes match the spec, @value{GDBN} will insert a breakpoint at
+each one of those probes.
+
@end table
The variable @code{$_exitcode} is automatically set to the exit code when
the program being debugged terminates.
+@item $_probe_argc
+@itemx $_probe_arg0@dots{}$_probe_arg11
+Arguments to a static probe. @xref{Static Probe Points}.
+
@item $_sdata
@vindex $_sdata@r{, inspect, convenience variable}
The variable @code{$_sdata} contains extra collected static tracepoint
Collect the return address. This is helpful if you want to see more
of a backtrace.
+@item $_probe_argc
+Collects the number of arguments from the static probe at which the
+tracepoint is located.
+@xref{Static Probe Points}.
+
+@item $_probe_arg@var{n}
+@var{n} is an integer between 0 and 11. Collects the @var{n}th argument
+from the static probe at which the tracepoint is located.
+@xref{Static Probe Points}.
+
@item $_sdata
@vindex $_sdata@r{, collect}
Collect static tracepoint marker specific data. Only available for
+2012-04-27 Sergio Durigan Junior <sergiodj@redhat.com>
+ Tom Tromey <tromey@redhat.com>
+
+ * gdb.base/default.exp: Add `$_probe_arg*' convenience
+ variables.
+ * gdb.base/stap-probe.c: New file.
+ * gdb.base/stap-probe.exp: New file.
+ * gdb.trace/stap-trace.c: New file.
+ * gdb.trace/stap-trace.exp: New file.
+ * gdb.cp/nextoverthrow.exp: Add check for SystemTap probe in
+ libgcc's unwinder.
+
2012-04-26 Maciej W. Rozycki <macro@codesourcery.com>
* gdb.arch/mips16-thunks-inmain.c: New file.
{$_sdata = void} \
{$_siginfo = void} \
{$_thread = 0} \
+ {$_probe_argc = <error: No frame selected>} \
+ {$_probe_arg0 = <error: No frame selected>} \
+ {$_probe_arg1 = <error: No frame selected>} \
+ {$_probe_arg2 = <error: No frame selected>} \
+ {$_probe_arg3 = <error: No frame selected>} \
+ {$_probe_arg4 = <error: No frame selected>} \
+ {$_probe_arg5 = <error: No frame selected>} \
+ {$_probe_arg6 = <error: No frame selected>} \
+ {$_probe_arg7 = <error: No frame selected>} \
+ {$_probe_arg8 = <error: No frame selected>} \
+ {$_probe_arg9 = <error: No frame selected>} \
+ {$_probe_arg10 = <error: No frame selected>} \
+ {$_probe_arg11 = <error: No frame selected>} \
}
#test show directories
--- /dev/null
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2012 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/>. */
+
+#if USE_PROBES
+
+#define _SDT_HAS_SEMAPHORES
+__extension__ unsigned short test_user_semaphore __attribute__ ((unused)) __attribute__ ((section (".probes")));
+#define TEST test_user_semaphore
+
+__extension__ unsigned short test_two_semaphore __attribute__ ((unused)) __attribute__ ((section (".probes")));
+#define TEST2 test_two_semaphore
+
+__extension__ unsigned short test_m4_semaphore __attribute__ ((unused)) __attribute__ ((section (".probes")));
+
+__extension__ unsigned short test_pstr_semaphore __attribute__ ((unused)) __attribute__ ((section (".probes")));
+
+__extension__ unsigned short test_ps_semaphore __attribute__ ((unused)) __attribute__ ((section (".probes")));
+#else
+
+#define TEST 1
+#define TEST2 1
+
+#endif
+
+#include <sys/sdt.h>
+
+/* We only support SystemTap and only the v3 form. */
+#if _SDT_NOTE_TYPE != 3
+#error "not using SystemTap v3 probes"
+#endif
+
+struct funcs
+{
+ int val;
+
+ const char *(*ps) (int);
+};
+
+static void
+m1 (void)
+{
+ if (TEST2)
+ STAP_PROBE (test, two);
+}
+
+static void
+m2 (void)
+{
+ if (TEST2)
+ STAP_PROBE (test, two);
+}
+
+static int
+f (int x)
+{
+ if (TEST)
+ STAP_PROBE1 (test, user, x);
+ return x+5;
+}
+
+static const char *
+pstr (int val)
+{
+ const char *a = "This is a test message.";
+ const char *b = "This is another test message.";
+
+ STAP_PROBE3 (test, ps, a, b, val);
+
+ return val == 0 ? a : b;
+}
+
+static void
+m4 (const struct funcs *fs, int v)
+{
+ STAP_PROBE3 (test, m4, fs->val, fs->ps (v), v);
+}
+
+int
+main()
+{
+ struct funcs fs;
+
+ fs.val = 42;
+ fs.ps = pstr;
+
+ f (f (23));
+ m1 ();
+ m2 ();
+
+ m4 (&fs, 0);
+ m4 (&fs, 1);
+
+ return 0; /* last break here */
+}
--- /dev/null
+# Copyright (C) 2012 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/>.
+
+set testfile stap-probe
+
+# Run the tests. We run the tests two different ways: once with a
+# plain probe, and once with a probe that has an associated semaphore.
+# This returns -1 on failure to compile or start, 0 otherwise.
+proc stap_test {exec_name {arg ""}} {
+ global testfile hex
+
+ if {[prepare_for_testing ${testfile}.exp ${exec_name} ${testfile}.c \
+ [concat $arg debug]]} {
+ return -1
+ }
+
+ if ![runto_main] {
+ return -1
+ }
+
+ gdb_test "print \$_probe_argc" "No SystemTap probe at PC $hex" \
+ "check argument not at probe point"
+
+ gdb_test "info probes stap" \
+ "test *user *$hex .*" \
+ "info probes stap"
+
+ if {[runto "-pstap test:user"]} {
+ pass "run to -pstap test:user"
+ } else {
+ fail "run to -pstap test:user"
+ }
+
+ # Test probe arguments.
+ gdb_test "print \$_probe_argc" " = 1" \
+ "print \$_probe_argc for probe user"
+ gdb_test "print \$_probe_arg0 == x" " = 1" \
+ "check \$_probe_arg0 for probe user"
+ gdb_test "print \$_probe_arg1" \
+ "Invalid probe argument 1 -- probe has 1 arguments available" \
+ "check \$_probe_arg1 for probe user"
+
+ # Set a breakpoint with multiple probe locations.
+ gdb_test "break -pstap test:two" \
+ "Breakpoint \[0-9\]+ at $hex.*2 locations.*" \
+ "set multi-location probe breakpoint (probe two)"
+
+ # Reinit GDB, set a breakpoint on probe m4.
+ delete_breakpoints
+ rerun_to_main
+ if {[runto "-pstap test:m4"]} {
+ pass "run to -pstap test:m4"
+ } else {
+ fail "run to -pstap test:m4"
+ }
+
+ # Testing probe arguments.
+ gdb_test "print \$_probe_argc" " = 3" \
+ "print \$_probe_argc for probe m4"
+ gdb_test "print \$_probe_arg0" " = 42" \
+ "check \$_probe_arg0 for probe m4"
+ gdb_test "print (const char *) \$_probe_arg1" \
+ " = $hex .This is a test message.*" \
+ "check \$_probe_arg1 for probe m4"
+ gdb_test "print \$_probe_arg2 == v" " = 1" \
+ "check \$_probe_arg2 for probe m4"
+
+ # Reinit GDB, set a breakpoint on probe ps.
+ delete_breakpoints
+ rerun_to_main
+ if {[runto "-pstap test:ps"]} {
+ pass "run to -pstap test:m4"
+ } else {
+ fail "run to -pstap test:m4"
+ }
+
+ gdb_test "print \$_probe_argc" " = 3" \
+ "print \$_probe_argc for probe ps"
+ gdb_test "print (const char *) \$_probe_arg1" \
+ " = $hex .This is another test message.*" \
+ "print \$_probe_arg1 for probe ps"
+
+ return 0
+}
+
+proc stap_test_no_debuginfo {exec_name {arg ""}} {
+ global testfile hex
+
+ if {[prepare_for_testing ${testfile}.exp ${exec_name} ${testfile}.c \
+ {$arg nodebug optimize=-O2}]} {
+ return -1
+ }
+
+ if {[runto "-pstap test:user"]} {
+ pass "run to -pstap test:user"
+ } else {
+ fail "run to -pstap test:user"
+ }
+
+ # Test probe arguments.
+ gdb_test "print \$_probe_argc" " = 1" \
+ "print \$_probe_argc for probe user"
+ gdb_test "print \$_probe_arg0 == 23" " = 1" \
+ "check \$_probe_arg0 for probe user"
+ gdb_test "print \$_probe_arg1" \
+ "Invalid probe argument 1 -- probe has 1 arguments available" \
+ "check \$_probe_arg1 for probe user"
+
+ # Set a breakpoint with multiple probe locations.
+ # In this scenario, we may expect more than 2 locations because of
+ # the optimizations (inlining, loop unrolling, etc).
+ gdb_test "break -pstap test:two" \
+ "Breakpoint .* at $hex.*\[0-9\]+ locations.*" \
+ "set multi-location probe breakpoint (probe two)"
+
+ # Reinit GDB, set a breakpoint on probe m4.
+ delete_breakpoints
+ rerun_to_main
+ if {[runto "-pstap test:m4"]} {
+ pass "run to -pstap test:m4"
+ } else {
+ fail "run to -pstap test:m4"
+ }
+
+ # Testing probe arguments.
+ gdb_test "print \$_probe_argc" " = 3" \
+ "print \$_probe_argc for probe m4"
+ gdb_test "print \$_probe_arg0" " = 42" \
+ "check \$_probe_arg0 for probe m4"
+ gdb_test "print (const char *) \$_probe_arg1" \
+ " = $hex .This is a test message.*" \
+ "check \$_probe_arg1 for probe m4"
+ gdb_test "print \$_probe_arg2 == 0" " = 1" \
+ "check \$_probe_arg2 for probe m4"
+
+ # Reinit GDB, set a breakpoint on probe ps.
+ delete_breakpoints
+ rerun_to_main
+ if {[runto "-pstap test:ps"]} {
+ pass "run to -pstap test:m4"
+ } else {
+ fail "run to -pstap test:m4"
+ }
+
+ gdb_test "print \$_probe_argc" " = 3" \
+ "print \$_probe_argc for probe ps"
+ gdb_test "print (const char *) \$_probe_arg1" \
+ " = $hex .This is another test message.*" \
+ "print \$_probe_arg1 for probe ps"
+
+ return 0
+}
+
+with_test_prefix "without semaphore, not optimized" {
+ if {[stap_test "stap-probe-nosem-noopt"] == -1} {
+ untested stap-probe.exp
+ return -1
+ }
+}
+
+with_test_prefix "with semaphore, not optimized" {
+ stap_test "stap-probe-sem-noopt" "-DUSE_PROBES"
+}
+
+with_test_prefix "without semaphore, optimized" {
+ stap_test_no_debuginfo "stap-probe-nosem-opt"
+}
+
+with_test_prefix "with semaphore, optimized" {
+ stap_test_no_debuginfo "stap-probe-sem-opt" "-DUSE_PROBES"
+}
set ok 0
}
}
+if {!$ok} {
+ gdb_test_multiple "info probe" "check for stap probe in unwinder" {
+ -re ".*libgcc.*unwind.*\r\n$gdb_prompt $" {
+ pass "check for stap probe in unwinder"
+ set ok 1
+ }
+ -re "\r\n$gdb_prompt $" {
+ }
+ }
+}
+
if {!$ok} {
unsupported "nextoverthrow.exp could not find _Unwind_DebugHook"
return -1
--- /dev/null
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2012 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/>. */
+
+#if USE_PROBES
+
+#define _SDT_HAS_SEMAPHORES
+__extension__ unsigned short test_user_semaphore __attribute__ ((unused)) __attribute__ ((section (".probes")));
+#define TEST test_user_semaphore
+
+__extension__ unsigned short test_two_semaphore __attribute__ ((unused)) __attribute__ ((section (".probes")));
+#define TEST2 test_two_semaphore
+
+#else
+
+#define TEST 1
+#define TEST2 1
+
+#endif /* USE_PROBES */
+
+#include <sys/sdt.h>
+
+/* We only support SystemTap and only the v3 form. */
+#if _SDT_NOTE_TYPE != 3
+#error "not using SystemTap v3 probes"
+#endif
+
+void
+m1 (int x)
+{
+ if (TEST2)
+ STAP_PROBE1 (test, two, x);
+}
+
+int
+f (int x)
+{
+ if (TEST)
+ STAP_PROBE1(test, user, x);
+ return x+5;
+}
+
+void
+nothing (void)
+{
+ int a = 1 + 1;
+ return;
+}
+
+int
+main()
+{
+ f (f (23));
+ m1 (46);
+ nothing (); /* end-here */
+
+ return 0;
+}
--- /dev/null
+# Copyright 2012 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 "stap-trace"
+set srcfile ${testfile}.c
+set executable ""
+set binfile_dir $objdir/$subdir
+
+set ws "\[\r\n\t \]+"
+set cr "\[\r\n\]+"
+
+# Only x86 and x86_64 targets are supported for now.
+
+if { ![istarget "x86_64-*"] && ![istarget "i?86-*"] } {
+ continue
+}
+
+proc compile_stap_bin {exec_name {arg ""}} {
+ global srcfile
+ global binfile_dir
+ global srcdir
+ global subdir
+ global executable
+
+ if { $arg != "" } {
+ set arg "additional_flags=$arg"
+ }
+
+ set executable ${exec_name}
+
+ if { [gdb_compile "$srcdir/$subdir/$srcfile" \
+ "$binfile_dir/$exec_name" \
+ executable [concat $arg debug nowarnings]] != "" } {
+ untested "Could not compile ${srcfile}"
+ return -1
+ }
+}
+
+proc prepare_for_trace_test {} {
+ global executable
+
+ clean_restart $executable
+
+ if { ![runto_main] } {
+ perror "Could not run to `main'."
+ continue
+ }
+
+ gdb_breakpoint [gdb_get_line_number "end-here"]
+}
+
+proc run_trace_experiment { test_probe msg } {
+ global gdb_prompt
+
+ set test "collect $msg: start trace experiment"
+ gdb_test_multiple "tstart" "$test" {
+ -re "^tstart\r\n$gdb_prompt $" {
+ pass "$test"
+ }
+ }
+
+ gdb_test "continue" \
+ "Continuing.*Breakpoint \[0-9\]+.*" \
+ "collect $msg: run trace experiment"
+ gdb_test "tstop" \
+ "\[\r\n\]+" \
+ "collect $msg: stop trace experiment"
+ gdb_test "tfind start" \
+ "#0 .*" \
+ "collect $msg: tfind test frame"
+}
+
+proc gdb_collect_probe_arg { msg probe val_arg0 } {
+ global gdb_prompt
+ global cr
+
+ prepare_for_trace_test
+
+ gdb_test "trace $probe" \
+ "Tracepoint \[0-9\]+ at .*" \
+ "collect $msg: set tracepoint"
+ gdb_trace_setactions "collect $msg: define actions" \
+ "" \
+ "collect \$_probe_arg0" "^$"
+
+ # Begin the test.
+ run_trace_experiment $msg $probe
+
+ gdb_test "print \$_probe_arg0" \
+ "\\$\[0-9\]+ = $val_arg0$cr" \
+ "collect $msg: collected probe arg0"
+}
+
+compile_stap_bin "stap-probe-nosem"
+
+clean_restart $executable
+if { ![runto_main] } {
+ perror "Could not run to `main'."
+ continue
+}
+
+if { ![gdb_target_supports_trace] } {
+ # Test cannot run on this target.
+ return 1;
+}
+
+gdb_collect_probe_arg "probe args without semaphore" "-probe-stap user" "23"
+gdb_exit
+
+compile_stap_bin "stap-probe-sem" "-DUSE_PROBES"
+gdb_collect_probe_arg "probe args with semaphore" "-probe-stap two" "46"
+
+# Finished!
+gdb_test "tfind none" ".*" ""
projects / binutils-gdb.git / commitdiff