Emit a warning when -z relro is unsupported

ld silently accepts -z relro and -z norelro for targets that lack the
necessary GNU_RELRO support.  This patch makes those targets emit a
warning instead, and adds testsuite infrastructure to detect when
relro is unsupported.

binutils/
	* testsuite/config/default.exp (ld_elf_shared_opt): Don't set.
	* testsuite/lib/binutils-common.exp (check_relro_support): New proc.
	(run_dump_test): Use check_relro_support to decide whether to pass
	extra ld option "-z norelro".
ld/
	* emultempl/elf.em (gld${EMULATION_NAME}_handle_option): Omit
	-z relro and -z norelro when target support for GNU_RELRO is lacking.
	(gld${EMULATION_NAME}_before_parse): Ignore RELRO default too.
	* emultempl/aarch64elf.em (gld${EMULATION_NAME}_before_parse): Ignore
	RELRO default when target support for GNU_RELRO is lacking.
	* emultempl/armelf.em (gld${EMULATION_NAME}_before_parse): Likewise.
	* emultempl/linux.em (gld${EMULATION_NAME}_before_parse): Likewise.
	* emultempl/scoreelf.em (gld${EMULATION_NAME}_before_parse): Likewise.
	* testsuite/config/default.exp (ld_elf_shared_opt): Don't set.
	* testsuite/ld-elf/pr16322.d: xfail when no relro support.
	* testsuite/ld-elf/pr22393-1a.d: Likewise.
	* testsuite/ld-elf/pr22393-1b.d: Likewise.
	* testsuite/ld-elf/shared.exp (pr20995-2.so, pr20995-2): Likewise.
	* testsuite/lib/ld-lib.exp (run_ld_link_tests): Use check_relro_support
	to decide whether to pass extra ld option "-z norelro".

1 files changed, 11 insertions, 15 deletions

diff --git a/ld/testsuite/ld-elf/shared.exp b/ld/testsuite/ld-elf/shared.exp
index 9d72cad..8f4ed71 100644
--- a/ld/testsuite/ld-elf/shared.exp
+++ b/ld/testsuite/ld-elf/shared.exp
@@ -454,16 +454,6 @@ run_ld_link_tests [list \
 	{pr20995b.s} {} "pr20995.so"] \
 ]
 
-# xfail on arm*-*-eabi*.  The list can be enlarged to those targets that
-# don't support GNU_RELRO.  For more details, please see discussions at:
-#   https://sourceware.org/ml/binutils/2017-01/msg00441.html
-run_ld_link_tests [list \
-    [list "Build pr20995-2.so" \
-	"-shared -z relro" "" "$AFLAGS_PIC" \
-	{pr20995c.s} {{readelf {-l --wide} pr20995-2so.r}} "pr20995-2.so"] \
-] "tic6x-*-*" "arm*-*-eabi*" "hppa*64*-*-hpux*" "aarch64*-*-elf*" \
-  "*-*-lynxos*" "arm*-*-nto*" "i?86-*-nto*" "sh*-*-nto*"
-
 # These targets don't copy dynamic variables into .bss.
 setup_xfail "alpha-*-*" "bfin-*-*" "ia64-*-*" "xtensa-*-*"
 # or don't have .data.rel.ro
@@ -474,16 +464,22 @@ run_ld_link_tests [list \
 	"$LFLAGS" "tmpdir/pr20995.so" "$AFLAGS_NONPIC" \
 	{pr20995a.s} {{readelf {-S --wide} pr20995.r}} "pr20995"]]
 
-# xfail on arm*-*-eabi* is particularly because of no support of GNU_RELRO.
-# Please see the link above for details.
-setup_xfail "alpha-*-*" "bfin-*-*" "ia64-*-*" "xtensa-*-*" "arm*-*-eabi*"
-setup_xfail "hppa*64*-*-hpux*" "aarch64*-*-elf*" "tic6x-*-*"
+# xfail on targets that don't support GNU_RELRO.
+#   For more details, please see discussions at:
+#   https://sourceware.org/ml/binutils/2017-01/msg00441.html
+run_ld_link_tests [list \
+    [list "Build pr20995-2.so" \
+	"-shared -z relro" "" "$AFLAGS_PIC" \
+	{pr20995c.s} {{readelf {-l --wide} pr20995-2so.r}} "pr20995-2.so"] \
+] {![check_relro_support]}
+
+setup_xfail alpha-*-* xtensa-*-*
 run_ld_link_tests [list \
     [list \
 	"pr20995-2" \
 	"$LFLAGS" "tmpdir/pr20995-2.so" "$AFLAGS_NONPIC" \
 	{pr20995a.s} {{readelf {-S --wide} pr20995.r}} "pr20995-2"]
-] "*-*-lynxos*" "arm*-*-nto*" "i?86-*-nto*" "sh*-*-nto*"
+] {![check_relro_support]}
 
 run_ld_link_tests [list \
     [list "Build pr22374 shared library" \