# Test that the linker reports undefined symbol errors correctly.
# By Ian Lance Taylor, Cygnus Support
#
#   Copyright (C) 1995-2025 Free Software Foundation, Inc.
#
# This file is part of the GNU Binutils.
#
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
# MA 02110-1301, USA.

set testund "undefined"
set testfn "undefined function"
set testline "undefined line"

if { ![check_compiler_available] } {
    verbose "Could not find C compiler!" 1
    untested $testund
    untested $testfn
    untested $testline
} elseif { ![ld_compile "$CC_FOR_TARGET -g $NOLTO_CFLAGS" $srcdir/$subdir/undefined.c tmpdir/undefined.o] } {
    verbose "Unable to compile test file!" 1
    unsupported $testund
    unsupported $testfn
    unsupported $testline
} else {
    remote_file host delete "tmpdir/undefined"

    set flags [big_or_little_endian]

    # Using -e start prevents the SunOS linker from trying to build a
    # shared library.  But don't use an entry point in BPF targets.
    switch -glob $target_triplet {
        bpf-*-* { set entry "" }
        * { set entry "-e start" }
    }

    send_log "$ld $entry $flags -o tmpdir/undefined tmpdir/undefined.o\n"
    set exec_output [run_host_cmd "$ld" "$entry $flags -o tmpdir/undefined tmpdir/undefined.o"]

    send_log "$exec_output\n"
    verbose "$exec_output"

    proc checkund { string testname } {
	global exec_output

	if [string match "*$string*" $exec_output] {
	    pass $testname
	} else {
	    fail $testname
	}
    }

    set mu "undefined reference to `*this_function_is_not_defined'"
    checkund $mu $testund

    # ARM PE defaults to using stabs debugging, which we can't handle
    # for a COFF file.
    #setup_xfail "arm*-*-pe*"

    # For Xtensa on GNU Linux systems (or any other system where PIC
    # code is always used), the address of the undefined function is
    # in a literal pool outside the function, so that both the
    # "undefined function" and "undefined line" tests fail.
    setup_xfail xtensa*-*-linux*
    setup_xfail loongarch*-*-*

    set mf "tmpdir/undefined.o* in function `function':"
    checkund $mf $testfn

    if ![is_elf_format] {
	# COFF SH gets this test wrong--it reports line 10, because
	# although the jump is at line 9, the function address, and
	# the reloc, is stored at the end of the function.
	setup_xfail "sh-*-*"

	# ARM PE defaults to using stabs debugging, which we can't
	# handle for a COFF file.
	#setup_xfail "arm*-*-pe*"
    }

    set ml {undefined.c:9:(*): undefined reference to `*this_function_is_not_defined'}
    # With targets that use elf/dwarf2, such as the arm-elf toolchain,
    # the code in bfd/elf.c:_bfd_elf_find_nearest_line() is called in
    # order to locate the file name/line number where the undefined
    # reference occurs.  Unfortunately this tries to use the dwarf2
    # debug information held in the .debug_info section.  This section
    # contains a series of comp_unit structures, each of which has a
    # low/high address range representing the span of memory locations
    # covered by that structure.  The structures also index into other
    # structures held in the .debug_line section and together they can
    # translate memory locations back into file/function/line number
    # addresses in the source code.  Since the information about the
    # memory region covered by a comp_unit is only determined at link
    # time, the low/high  addresses in the .debug_info section and the
    # line addresses in the .debug_line section are computed by
    # generating relocs against known symbols in the object code.
    #
    # When the undefined reference is detected, the relocs in the
    # dwarf2 debug sections have not yet been resolved, so the
    # low/high addresses and the line number address are all set at
    # zero.  Thus when _bfd_elf_find_nearest_line() calls
    # _bfd_dwarf2_find_nearest_line() no comp_unit can be found which
    # actually covers the address where the reference occurred, and so
    # _bfd_elf_find_nearest_line() fails.
    #
    # The upshot of all of this, is that the error message reported by
    # the linker, instead of having a source file name & line number
    # as in:
    #
    #   undefined.c:9: undefined reference to `this_function_is_not_defined'
    #
    # has an object file & section address instead:
    #
    #   undefined.0(.text+0xc): undefined reference to `this_function_is_not_defined'
    #
    # hence the xfails below.

    setup_xfail mcore-*-elf
    setup_xfail mep-*-*
    setup_xfail mips-sgi-irix6*
    # Fails for the MSP430 because it uses SYM_DIFF relocs but it does
    # not provide a special_function for handling them.  If
    # optimization is enabled then this test passes because
    # function()'s prologue is eliminated.
    setup_xfail "msp430-*-*"

    # The undefined test fails on 31 bit s/390 because the address of
    # the function `this_function_is_not_defined' is stored in the
    # literal pool of the function.  Therefore the line number in the
    # error message is 8 instead of 9. On 64 bit s/390 this works
    # because of the new brasl instruction that doesn't need a literal
    # pool entry.
    # FIXME: this test has been an XPASS since 2021-04 (and maybe
    # earlier, that's just where my logs went back to).  Testing the
    # gcc version is a wild guess at what might have changed.
    if ![at_least_gcc_version 11 0] {
	setup_xfail s390-*-*
    }

    # See comments above for Xtensa.
    setup_xfail xtensa*-*-linux*
    setup_xfail hppa*64*-*-*

    # eBPF doesn't support dwarf yet.
    setup_xfail bpf-*-*
    setup_xfail loongarch*-*-*

    checkund $ml $testline
}

# Undefined symbols should become dynamic when linking a shared lib.
set testname "undefined symbols in shared lib"

set asflags ""
switch -glob $target_triplet {
    aarch64* -
    arm* -
    powerpc64* { set asflags "--defsym BL=1" }
    powerpc* { set asflags "--defsym BLPLT=1" }
    hppa* { set asflags "--defsym HPPA=1" }
    i\[3-7\]86* -
    x86_64* { set asflags "--defsym CALLPLT=1" }
}

if { ![is_elf_format] || ![check_shared_lib_support]} then {
    unsupported $testname
} elseif {![ld_assemble $as "$asflags $srcdir/$subdir/fundef.s" \
		tmpdir/fundef.o]} then {
    fail $testname
} elseif {![ld_link $ld tmpdir/fundef.so \
		"-shared --allow-shlib-undefined tmpdir/fundef.o"]} then {
    setup_xfail tic6x-*-*
    fail $testname
} else {
    set exec_output [run_host_cmd "$nm" "-D tmpdir/fundef.so"]
    set exec_output [prune_warnings $exec_output]

    if { ($asflags == ""
	  || ([regexp ".* undef_fun_typed.*" $exec_output]
	      && [regexp ".* undef_fun_notype.*" $exec_output]))
	 && [regexp ".* undef_data.*" $exec_output]
	 && [regexp ".* undef_pfun.*" $exec_output]
	 && [regexp ".* undef_notype.*" $exec_output]} then {
	pass "$testname (dyn sym)"
    } else {
	fail "$testname (dyn sym)"
    }

    global READELF
    set exec_output [run_host_cmd "$READELF" "-r tmpdir/fundef.so"]
    set exec_output [prune_warnings $exec_output]

    # We ought to get two .rel{a}.plt and three .rel{a}.dyn relocs,
    # except for MIPS targets whose psABI mandates an extra
    # R_MIPS_NONE relocation, also used to pad n64 relocation
    # triplets, and S+core targets using an extra R_SCORE_NONE
    # relocation, so adjust for that.
    switch -glob $target_triplet {
	"mips64*-*-openbsd*" -
	"mips64*-*-*-gnuabi64" {
	    set none_count 6
	    set reloc_count 4
	}
	"mips*" -
	"score*" {
	    set none_count 1
	    set reloc_count 4
	}
	"*" {
	    set none_count 0
	    set reloc_count 3
	}
    }

    if { ($asflags == "" || [regexp ".* contains 2 .*" $exec_output])
	 && [regexp ".* contains $reloc_count .*" $exec_output]
	 && [regexp -all "_NONE" $exec_output] == $none_count } then {
	pass "$testname (dyn reloc)"
    } else {
	fail "$testname (dyn reloc)"
    }
}