binutils-gdb/gdb/testsuite/gdb.base/gnu-ifunc.exp

# Copyright (C) 2009-2020 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 {[skip_shlib_tests]} {
    return 0
}

if {[skip_ifunc_tests]} {
    return 0
}

standard_testfile .c
set staticexecutable ${testfile}-static
set staticbinfile [standard_output_file ${staticexecutable}]

set libfile "${testfile}-lib"
set libsrc ${libfile}.c

set final_file "${testfile}-final"
set final_src ${final_file}.c

if [get_compiler_info] {
    return -1
}

# Return the binary suffix appended to program and library names to
# make each testcase variant unique.
proc make_binsuffix {resolver_attr resolver_debug final_debug} {
    return "$resolver_attr-$resolver_debug-$final_debug"
}

# Compile the testcase.  RESOLVER_ATTR is true if we're testing with
# an ifunc resolver that has a different name from the user symbol,
# specified with GCC's __attribute__ ifunc.  RESOLVER_DEBUG is true
# iff the resolver was compiled with debug info.  FINAL_DEBUG is true
# iff the target function was compiled with debug info.
proc build {resolver_attr resolver_debug final_debug} {
    global srcdir subdir srcfile binfile
    global libsrc lib_so libfile
    global exec_opts executable
    global hex gdb_prompt
    global final_file final_src

    set suffix [make_binsuffix $resolver_attr $resolver_debug $final_debug]

    set lib_so [standard_output_file ${libfile}-$suffix.so]
    # $lib_o must not have {debug}, it would override the STT_GNU_IFUNC ELF markers.
    set lib_o [standard_output_file ${libfile}-$suffix.o]

    set exec_opts [list debug shlib=$lib_so]

    set lib_opts {}
    set final_opts {}

    if {$resolver_attr} {
	lappend lib_opts "additional_flags=-DIFUNC_RESOLVER_ATTR"
    }

    if {$resolver_debug} {
	lappend lib_opts "debug"
    }

    if {$final_debug} {
	lappend final_opts "debug"
    }

    set final_o [standard_output_file $final_file-$suffix.o]

    if { [gdb_compile_shlib ${srcdir}/${subdir}/$libsrc \
	      $lib_so $lib_opts] != ""
	 || [gdb_compile ${srcdir}/${subdir}/$final_src \
		 $final_o object $final_opts] != ""
	 || [gdb_compile [list ${srcdir}/${subdir}/$srcfile $final_o] \
		 $binfile-$suffix executable $exec_opts] != ""} {
	untested "failed to compile testcase"
	return 0
    }

    return 1
}

# Test setting a breakpoint on a ifunc function before and after the
# ifunc is resolved.  For the description of RESOLVER_ATTR,
# RESOLVER_DEBUG and FINAL_DEBUG, see the "build" procedure above.
proc_with_prefix set-break {resolver_attr resolver_debug final_debug} {
    global binfile libfile lib_so
    global hex decimal
    global gdb_prompt

    set suffix [make_binsuffix $resolver_attr $resolver_debug $final_debug]

    set lib_so [standard_output_file ${libfile}-$suffix.so]
    clean_restart $binfile-$suffix
    gdb_load_shlib ${lib_so}

    if ![runto_main] then {
	fail "can't run to main"
	return 1
    }

    gdb_breakpoint [gdb_get_line_number "break-at-call"]
    gdb_continue_to_breakpoint "break-at-call" ".*break-at-call.*"

    set ws "\[ \t\]+"
    set dot "\\.?"

    if {$resolver_attr} {
	set gnu_ifunc_resolver "gnu_ifunc_resolver"
    } else {
	set gnu_ifunc_resolver "gnu_ifunc"
    }

    if {!$resolver_debug} {
	set gnu_ifunc_resolver "${dot}${gnu_ifunc_resolver}"
    }

    if {!$final_debug} {
	set final "${dot}final"
    } else {
	set final "final"
    }

    with_test_prefix "before resolving" {
	delete_breakpoints
	gdb_test "break gnu_ifunc" \
	    "Breakpoint $decimal at gnu-indirect-function resolver at $hex"
	gdb_test "info breakpoints" \
	    "$decimal${ws}STT_GNU_IFUNC resolver${ws}keep${ws}y${ws}$hex <${gnu_ifunc_resolver}>"

	# Make the breakpoint conditional on a condition that always
	# fails.  This is so that when the ifunc-resolver breakpoint
	# triggers, GDB resumes the program immediately.
	gdb_test_no_output "condition \$bpnum 0"
    }

    global final_src

    with_test_prefix "resolve" {
	gdb_breakpoint [gdb_get_line_number "break-at-exit"]
	gdb_continue_to_breakpoint "break-at-exit" ".*break-at-exit.*"
    }

    with_test_prefix "after resolving" {
	if {!$final_debug} {
	    # Set a breakpoint both at the ifunc, and at the ifunc's
	    # target.  GDB should resolve both to the same address.
	    # Start with the ifunc's target.
	    set addr "-"
	    set test "break final"
	    # Extract the address without the leading "0x", because
	    # addresses in "info break" output include leading 0s
	    # (like "0x0000ADDR").
	    set hex_number {[0-9a-fA-F][0-9a-fA-F]*}
	    gdb_test_multiple $test $test {
		-re "Breakpoint .* at 0x($hex_number)\r\n$gdb_prompt $" {
		    set addr $expect_out(1,string)
		    pass $test
		}
	    }

	    # Now set a break at the ifunc.
	    gdb_test "break gnu_ifunc" "Breakpoint .* at 0x$addr"
	    set location "$decimal${ws}breakpoint${ws}keep${ws}y${ws}0x0*$addr${ws}<${final}\\+.*>"
	} else {
	    set lineno -1
	    set test "break final"
	    gdb_test_multiple $test $test {
		-re "Breakpoint .* at $hex: file .*$final_src, line ($decimal)\\.\r\n$gdb_prompt $" {
		    set lineno $expect_out(1,string)
		    pass $test
		}
	    }
	    gdb_test "break gnu_ifunc" "Breakpoint .* at $hex: file .*$final_src, line $lineno\\."
	    set location "$decimal${ws}breakpoint${ws}keep${ws}y${ws}$hex in final at .*$final_src:$lineno"
	}

	# The first location here is for the breakpoint that was set
	# before the ifunc was resolved.  It should be resolved by
	# now, and it should have the exact same address/line as the
	# other two locations.
	gdb_test "info breakpoints" "$location\r\n.*$location\r\n$location"
    }
}

# Misc GNU ifunc tests.  For the description of RESOLVER_ATTR,
# RESOLVER_DEBUG and FINAL_DEBUG, see the "build" procedure above.
proc misc_tests {resolver_attr resolver_debug final_debug} {
    global srcdir subdir srcfile binfile
    global libsrc lib_so libfile
    global exec_opts executable
    global hex gdb_prompt
    global final_file final_src

    set suffix [make_binsuffix $resolver_attr $resolver_debug $final_debug]

    if {$resolver_attr} {
	set gnu_ifunc_resolver "gnu_ifunc_resolver"
    } else {
	set gnu_ifunc_resolver "gnu_ifunc"
    }

    set dot "\\.?"

    if {!$resolver_debug} {
	set gnu_ifunc_resolver "${dot}${gnu_ifunc_resolver}"
    }

    if {!$final_debug} {
	set final "${dot}final"
    } else {
	set final "final"
    }

    # Start with a fresh gdb.

    clean_restart $binfile-$suffix
    gdb_load_shlib ${lib_so}

    if ![runto_main] then {
	fail "can't run to main"
	return 1
    }

    # The "if" condition is artifical to test regression of a former patch.
    gdb_breakpoint "[gdb_get_line_number "break-at-nextcall"] if i && (int) gnu_ifunc (i) != 42"

    gdb_breakpoint [gdb_get_line_number "break-at-call"]
    gdb_continue_to_breakpoint "break-at-call" ".*break-at-call.*"

    # Test GDB will automatically indirect the call.

    if {!$resolver_debug && !$final_debug} {
	gdb_test "p gnu_ifunc()" \
	    "'${dot}final' has unknown return type; cast the call to its declared return type"
	gdb_test "p gnu_ifunc (3)" \
	    "'${dot}final' has unknown return type; cast the call to its declared return type"
	gdb_test "p (int) gnu_ifunc (3)" " = 4"
    } else {
	gdb_test "p gnu_ifunc()" "Too few arguments in function call\\."
	gdb_test "p gnu_ifunc (3)" " = 4"
    }

    # Test that the resolver received its argument.

    set actual_hwcap "0x0"
    set test "info auxv"
    gdb_test_multiple $test $test {
	-re "\r\n\\d+\\s+AT_HWCAP\[^\r\n\]+($hex)\r\n.*$gdb_prompt $" {
	    set actual_hwcap $expect_out(1,string)
	}
	-re ".*$gdb_prompt $" {
	    pass "$test (no HWCAP)"
	}
    }

    gdb_test "p/x resolver_hwcap" "= $actual_hwcap" "resolver received HWCAP"

    # Test GDB will skip the gnu_ifunc resolver on first call.

    # Even if the resolver has debug info, stepping into an ifunc call
    # should skip the resolver.
    if {!$final_debug} {
	# Make GDB stop stepping even if it steps into a function with
	# no debug info.
	gdb_test_no_output "set step-mode on"
	gdb_test "step" "$hex in ${dot}final \\\(\\\)"
    } else {
	gdb_test "step" "\r\nfinal .*"
    }

    # Test GDB will not break before the final chosen implementation.

    # Also test a former patch regression:
    # Continuing.
    # Error in testing breakpoint condition:
    # Attempt to take address of value not located in memory.
    #
    # Breakpoint 2, main () at ./gdb.base/gnu-ifunc.c:33

    gdb_test "continue" \
	"Continuing.\r\n\r\nBreakpoint .* (at|in) .*break-at-nextcall.*" \
	"continue to break-at-nextcall"

    gdb_breakpoint "gnu_ifunc"

    gdb_continue_to_breakpoint "nextcall gnu_ifunc"

    gdb_test "frame" \
	"#0 +(0x\[0-9a-f\]+ in +)?${final} \\(.*" "nextcall gnu_ifunc skipped"

    # Check any commands not doing an inferior call access the address of the
    # STT_GNU_IFUNC resolver, not the target function.

    if {[istarget powerpc64-*] && [is_lp64_target]} {
	# With only minimal symbols GDB provides the function descriptors.  With
	# full debug info the function code would be displayed.
    }

    gdb_test "p gnu_ifunc" \
	" = {<text gnu-indirect-function variable, no debug info>} 0x\[0-9a-f\]+ <${gnu_ifunc_resolver}>" \
	"p gnu_ifunc executing"
    gdb_test "info sym gnu_ifunc" \
	"${gnu_ifunc_resolver} in section .*" \
	"info sym gnu_ifunc executing"

    set test "info addr gnu_ifunc"
    if {!$resolver_attr && $resolver_debug} {
	gdb_test_multiple $test $test {
	    -re "Symbol \"gnu_ifunc\" is a function at address (0x\[0-9a-f\]+).*$gdb_prompt $" {
		pass $test
	    }
	}
    } else {
	gdb_test_multiple $test $test {
	    -re "Symbol \"gnu_ifunc\" is at (0x\[0-9a-f\]+) in .*$gdb_prompt $" {
		pass $test
	    }
	}
    }
    gdb_test "info sym $expect_out(1,string)" \
	"${gnu_ifunc_resolver} in section .*" \
	"info sym <gnu_ifunc-address>"

    # Test calling the resolver directly instead of the ifunc symbol.
    # Can only do that if the ifunc and the ifunc resolver have
    # different names.
    if {$resolver_attr} {
	if {$resolver_debug} {
	    if {[istarget powerpc64-*] && [is_lp64_target]} {
		gdb_test "p gnu_ifunc_resolver(0)" \
		    " = \\(int \\(\\*\\)\\(int\\)\\) @$hex: $hex <${final}>"
	    } else {
		gdb_test "p gnu_ifunc_resolver(0)" \
		    " = \\(int \\(\\*\\)\\(int\\)\\) $hex <final>"
	    }
	} else {
	    gdb_test "p gnu_ifunc_resolver(0)" \
		"'${gnu_ifunc_resolver}' has unknown return type; cast the call to its declared return type"
	    gdb_test "p (void *) gnu_ifunc_resolver(0)" \
		" = \\(void \\*\\) $hex <${final}>"
	}
    }
}

# Test all the combinations of:
#
# - An ifunc resolver with the same name as the ifunc symbol vs an
#   ifunc resolver with a different name as the ifunc symbol.
#
# - ifunc resolver compiled with and without debug info.  This ensures
#   that GDB understands that a function not a regular function by
#   looking at the STT_GNU_IFUNC type in the elf symbols.  DWARF has
#   no way to express the STT_GNU_IFUNC type.
#
# - ifunc target function (resolved) compiled with and without debug
#   info.
foreach_with_prefix resolver_attr {0 1} {
    foreach_with_prefix resolver_debug {0 1} {
	foreach_with_prefix final_debug {0 1} {
	    if { [build $resolver_attr $resolver_debug $final_debug] != 0 } {
		misc_tests $resolver_attr $resolver_debug $final_debug
		set-break $resolver_attr $resolver_debug $final_debug
	    }
	}
    }
}

# Test statically linked ifunc resolving during inferior start.
# https://bugzilla.redhat.com/show_bug.cgi?id=624967

with_test_prefix "static" {
    # Compile $staticbinfile separately as it may exit on error
    # (ld/12595).

    set lib_o [standard_output_file ${libfile}.o]
    set final_o [standard_output_file ${final_file}.o]
    if { [gdb_compile ${srcdir}/${subdir}/$libsrc $lib_o object {}] != ""
	 || [gdb_compile ${srcdir}/${subdir}/$final_src $final_o object {}] != ""
	 || [gdb_compile "${srcdir}/${subdir}/$srcfile $lib_o $final_o" \
		 $staticbinfile executable {debug}] != "" } {
	untested "failed to compile second testcase"
	return -1
    }

    clean_restart $staticexecutable

    gdb_breakpoint "gnu_ifunc"
    gdb_breakpoint "main"
    gdb_run_cmd
    gdb_test "" "Breakpoint \[0-9\]*, main .*" "static gnu_ifunc"
}