binutils-gdb/gdb/testsuite/gdb.base/gnu-ifunc.exp
Luis Machado 3d4aae4860 Build gdb.base/gnu-ifunc.exp with lazy binding
The test expects the ifunc resolver to run lazily, at a later stage.

Depending on the distro and toolchain configuration, this is not the
case. Some configurations use non-lazy binding and thus the ifunc resolver
resolves all the ifunc references very early in the process startup, before
main.

Ubuntu is one such case. It has switched its toolchains to pass -Wl,z,now by
default, since 16.04. This wasn't a problem before 20.04 (at least for
aarch64) because the toolchains did not support ifunc's.

Forcing lazy binding makes the test run as expected, as opposed to the 80 or
so failures it showed before the change.

Tested on aarch64-linux/x86_64-linux Ubuntu 20.04.

gdb/testsuite:

2021-02-08  Luis Machado  <luis.machado@linaro.org>

	* gdb.base/gnu-ifunc.exp (build): Pass -Wl,z,lazy.
2021-02-08 18:56:48 -03:00

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# Copyright (C) 2009-2021 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=$lib_so]
set lib_opts {}
set final_opts {}
# Force lazy binding so we don't resolve everything at process startup.
lappend exec_opts "additional_flags=-Wl,-z,lazy"
lappend lib_opts "additional_flags=-Wl,-z,lazy"
if {$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"
}