old-cross-binutils/ld/testsuite/ld-scripts/provide.exp
Andrew Burgess c05b575a8d ld: Don't evaluate unneeded PROVIDE expressions.
When creating a linker mapfile (using -Map=MAPFILE), we previously would
always try to evaluate the expression from a PROVIDE statement.

However, this is not always safe, consider:

  PROVIDE (foo = 0x10);
  PROVIDE (bar = foo);

In this example, if neither 'foo' or 'bar' is needed, then while
generating the linker mapfile evaluating the expression for 'foo' is
harmless (just the value 0x10).  However, evaluating the expression for
'bar' requires the symbol 'foo', which is undefined.  This used to cause
a fatal error.

This patch changes the behaviour, so that when the destination of the
PROVIDE is not defined (that is the PROVIDE is not going to provide
anything) the expression is not evaluated, and instead a special string
is displayed to indicate that the linker is discarding the PROVIDE
statement.

This change not only fixes the spurious undefined symbol error, but also
means that a user can now tell if a PROVIDE statement has provided
anything by inspecting the linker mapfile, something that could not be
done before.

ld/ChangeLog:

	* ldlang.c (print_assignment): Only evaluate the expression for a
	PROVIDE'd assignment when the destination is being defined.
	Display a special message for PROVIDE'd symbols that are not being
	provided.

ld/testsuite/ChangeLog:

	* ld-scripts/provide-4.d: New file.
	* ld-scripts/provide-4-map.d: New file.
	* ld-scripts/provide-4.t: New file.
	* ld-scripts/provide-5.d: New file.
	* ld-scripts/provide-5.s: New file.
	* ld-scripts/provide-5-map.d: New file.
	* ld-scripts/provide-5.t: New file.
	* ld-scripts/provide.exp: Run the provide-4.d and provide-5.d
	tests.
2015-01-20 09:49:27 +00:00

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# Test PROVIDE in a linker script.
# By Nathan Sidwell, CodeSourcery LLC
# Copyright (C) 2004-2015 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.
# AIX maps .text and .data to other sections.
# a.out objdump displays the file header inside the text segment,
# confusing run_dump_test.
if {[istarget "rs6000-*-aix*"] || [is_aout_format]} {
unsupported provide-1
unsupported provide-2
unsupported provide-3
return
}
global LDFLAGS
set saved_LDFLAGS "$LDFLAGS"
if [istarget "x86_64-*-mingw*"] then {
set LDFLAGS "$LDFLAGS --image-base 0"
}
run_dump_test provide-1
run_dump_test provide-2
setup_xfail *-*-*
run_dump_test provide-3
run_dump_test provide-4
run_dump_test provide-5
set LDFLAGS "$saved_LDFLAGS"