binutils-gdb/gdb/testsuite/gdb.base/stap-probe.exp

# Copyright (C) 2012-2022 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/>.

standard_testfile

# Count the number of probes of TYPE (either 'stap' or 'dtrace'),
# from provider matching PROVIDER, with a name matching NAME, and from
# an objec file matching OBJECT.
#
# The OBJECT is optional, in which case all objects will be matched.
#
# If any error condition is detected, then perror is called, and -1
# returned.
#
# Otherwise, returns an integer, 0 or greater.
proc gdb_count_probes { type provider name { object "" }} {
    set cmd "info probes ${type} ${provider} ${name}"
    if { $object != "" } {
	set cmd "$cmd ${object}"
    }

    set probe_count 0
    set no_probes_line false
    gdb_test_multiple $cmd "" {
	-re "^$cmd\r\n" {
	    exp_continue
	}
	-re "^Type\\s+Provider\\s+Name\\s+Where\\s+Semaphore\\s+Object\\s*\r\n" {
	    exp_continue
	}
	-re "^\\s*\r\n" {
	    exp_continue
	}
	-re "^stap\[^\r\n\]+\r\n" {
	    incr probe_count
	    exp_continue
	}
	-re "^dtrace\[^\r\n\]+\r\n" {
	    incr probe_count
	    exp_continue
	}
	-re "^No probes matched\\.\r\n" {
	    set no_probes_line true
	    exp_continue
	}
	-re "^$::gdb_prompt $" {
	    pass $gdb_test_name
	}
    }

    if { [expr $no_probes_line && $probe_count > 0] \
	     || [expr !$no_probes_line && $probe_count == 0] } {
	perror "Mismatch between no probes found line, and probes count"
	return -1
    }

    return $probe_count
}

proc check_for_usable_xmm0_probe { binfile } {
    set readelf_program [gdb_find_readelf]
    set binfile [standard_output_file $binfile]
    set command "exec $readelf_program -n $binfile"
    verbose -log "command is $command"
    set result [catch $command output]
    verbose -log "result is $result"
    verbose -log "output is $output"

    # We don't actually check RESULT.  Sometimes readelf gives
    # warnings about gaps in some of the notes data.  This is
    # unrelated to the staps probes, but still causes readelf to exit
    # with non-zero status.
    #
    # Instead, just check the output.  If readelf failed to run then
    # the output will be empty, and the following regexps will fail to
    # match.

    # First, look for the xmmreg probe, and if we find it, grab the
    # argument string.
    if ![regexp {\n\s+Provider: test\n\s+Name: xmmreg\n[^\n]+\n\s+Arguments: ([^\n]+)\n} $output ignore arguments] {
	verbose -log "APB: Couldn't find probe at all"
	return false
    }

    verbose -log "APB: Matched on '$ignore'"
    verbose -log "APB: arguments: '$arguments'"

    # Check the the argument string mentions xmm0.
    if ![regexp {@%?xmm0} $arguments] {
	verbose -log "APB: Prove doesn't use xmm0 register"
	return false
    }

    # Success!  We have a probe that uses xmm0 for an argument.
    return true
}

# 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 {args ""}} {
    global testfile hex srcfile

    if {[prepare_for_testing "failed to prepare" ${exec_name} $srcfile \
	   [concat $args debug]]} {
	return -1
    }

    set semaphore_addr_var ""
    if {[string first "-DUSE_SEMAPHORES" $args] == -1} {
	gdb_test_no_output "set breakpoint always-inserted on"
	set semaphore_addr_var \
	    [get_hexadecimal_valueof "&relocation_marker" "0"\
		"get original address of relocation_marker"]
    }

    if ![runto_main] {
	return -1
    }

    gdb_test "print \$_probe_argc" "No probe at PC $hex" \
	"check argument not at probe point"

    if {[string first "-DUSE_SEMAPHORES" $args] != -1} {
	gdb_test_lines "info probes stap" "" \
	    "test *user *$hex *$hex .*"
    } else {
	gdb_test_lines "info probes stap" "" \
	    "test *user *$hex .*"
    }

    if {[runto "-pstap test:user"]} {
	pass "run to -pstap test:user"
    } else {
	fail "run to -pstap test:user"
    }

    if {[string first "-DUSE_SEMAPHORES" $args] == -1} {
	set updated_semaphore_addr_var \
	    [get_hexadecimal_valueof "&relocation_marker" \
		 "0" "get revised relocation_marker address"]
	set relocation_base \
	   [expr $updated_semaphore_addr_var - $semaphore_addr_var]
	if {$relocation_base != 0} {
	   # Checks that GDB doesn't mistakenly relocate and write to null
	   # semaphore addresses.  If it were to relocate a zero-valued
	   # semaphore address and increment the value at that address, we
	   # would expect to see "\200ELF" here instead.
	   gdb_test "p (*(char*) $relocation_base)@4" \
		" = \"\\\\177ELF\"" \
		"null semaphore relocation"
	}
    }

    # 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
    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
    if {[runto "-pstap test:ps"]} {
      pass "run to -pstap test:ps"
    } else {
      fail "run to -pstap test:ps"
    }

    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"

    # Check the probe is using the xmm0 register.
    if [check_for_usable_xmm0_probe $exec_name] {

	delete_breakpoints
	if {[runto "-pstap test:xmmreg"]} {
	    pass "run to -pstap test:xmmreg"
	} else {
	    fail "run to -pstap test:xmmreg"
	}

	gdb_test "print \$_probe_argc" " = 1" \
	    "print \$_probe_argc for probe xmmreg"
	gdb_test "print/x \$_probe_arg0" " = 0x1234" \
	    "check \$_probe_arg0 for probe xmmreg"
    } else {
	unsupported "print probe argument from \$xmm0 register"
    }

    return 0
}

proc stap_test_no_debuginfo {exec_name {args ""}} {
    global testfile hex

    if {[prepare_for_testing "failed to prepare" ${exec_name} ${testfile}.c \
	   [concat $args 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
    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
    if {[runto "-pstap test:ps"]} {
      pass "run to -pstap test:ps"
    } else {
      fail "run to -pstap test:ps"
    }

    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"

    # Reinit GDB, set a breakpoint on probe ps.
    if { [gdb_count_probes stap test xmmreg] > 0 } {
	delete_breakpoints
	if {[runto "-pstap test:xmmreg"]} {
	    pass "run to -pstap test:xmmreg"
	} else {
	    fail "run to -pstap test:xmmreg"
	}

	gdb_test "print \$_probe_argc" " = 1" \
	    "print \$_probe_argc for probe xmmreg"
	gdb_test "print/x \$_probe_arg0" " = 0x1234" \
	    "check \$_probe_arg0 for probe xmmreg"
    }

    return 0
}

with_test_prefix "without semaphore, not optimized" {
    if {[stap_test "stap-probe-nosem-noopt"] == -1} {
	untested "stap probe test failed"
	  return -1
    }

    foreach_with_prefix pie { "nopie" "pie" } {
	stap_test "stap-probe-nosem-noopt-$pie" $pie
    }
}

with_test_prefix "with semaphore, not optimized" {
    stap_test "stap-probe-sem-noopt" additional_flags=-DUSE_SEMAPHORES
}

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" additional_flags=-DUSE_SEMAPHORES
}