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".

5 files changed, 36 insertions, 0 deletions

diff --git a/ld/emultempl/aarch64elf.em b/ld/emultempl/aarch64elf.em
index d0519b3..a036da9 100644
--- a/ld/emultempl/aarch64elf.em
+++ b/ld/emultempl/aarch64elf.em
@@ -47,7 +47,13 @@ gld${EMULATION_NAME}_before_parse (void)
   config.has_shared = `if test -n "$GENERATE_SHLIB_SCRIPT" ; then echo TRUE ; else echo FALSE ; fi`;
   config.separate_code = `if test "x${SEPARATE_CODE}" = xyes ; then echo TRUE ; else echo FALSE ; fi`;
   link_info.check_relocs_after_open_input = TRUE;
+EOF
+if test -n "$COMMONPAGESIZE"; then
+fragment <<EOF
   link_info.relro = DEFAULT_LD_Z_RELRO;
+EOF
+fi
+fragment <<EOF
 }
 
 static void
diff --git a/ld/emultempl/armelf.em b/ld/emultempl/armelf.em
index fb5bbf8..34372ba 100644
--- a/ld/emultempl/armelf.em
+++ b/ld/emultempl/armelf.em
@@ -60,7 +60,13 @@ gld${EMULATION_NAME}_before_parse (void)
   config.has_shared = `if test -n "$GENERATE_SHLIB_SCRIPT" ; then echo TRUE ; else echo FALSE ; fi`;
   config.separate_code = `if test "x${SEPARATE_CODE}" = xyes ; then echo TRUE ; else echo FALSE ; fi`;
   link_info.check_relocs_after_open_input = TRUE;
+EOF
+if test -n "$COMMONPAGESIZE"; then
+fragment <<EOF
   link_info.relro = DEFAULT_LD_Z_RELRO;
+EOF
+fi
+fragment <<EOF
 }
 
 static void
diff --git a/ld/emultempl/elf.em b/ld/emultempl/elf.em
index c577e8b..356f345 100644
--- a/ld/emultempl/elf.em
+++ b/ld/emultempl/elf.em
@@ -82,7 +82,13 @@ gld${EMULATION_NAME}_before_parse (void)
   config.has_shared = `if test -n "$GENERATE_SHLIB_SCRIPT" ; then echo TRUE ; else echo FALSE ; fi`;
   config.separate_code = `if test "x${SEPARATE_CODE}" = xyes ; then echo TRUE ; else echo FALSE ; fi`;
   link_info.check_relocs_after_open_input = TRUE;
+EOF
+if test -n "$COMMONPAGESIZE"; then
+fragment <<EOF
   link_info.relro = DEFAULT_LD_Z_RELRO;
+EOF
+fi
+fragment <<EOF
   link_info.separate_code = DEFAULT_LD_Z_SEPARATE_CODE;
 }
 
@@ -805,10 +811,16 @@ fragment <<EOF
 	link_info.combreloc = FALSE;
       else if (strcmp (optarg, "nocopyreloc") == 0)
 	link_info.nocopyreloc = TRUE;
+EOF
+if test -n "$COMMONPAGESIZE"; then
+fragment <<EOF
       else if (strcmp (optarg, "relro") == 0)
 	link_info.relro = TRUE;
       else if (strcmp (optarg, "norelro") == 0)
 	link_info.relro = FALSE;
+EOF
+fi
+fragment <<EOF
       else if (strcmp (optarg, "separate-code") == 0)
 	link_info.separate_code = TRUE;
       else if (strcmp (optarg, "noseparate-code") == 0)
diff --git a/ld/emultempl/linux.em b/ld/emultempl/linux.em
index e9d802c..1444610 100644
--- a/ld/emultempl/linux.em
+++ b/ld/emultempl/linux.em
@@ -52,7 +52,13 @@ gld${EMULATION_NAME}_before_parse (void)
   input_flags.dynamic = TRUE;
   config.has_shared = TRUE;
   link_info.check_relocs_after_open_input = TRUE;
+EOF
+if test -n "$COMMONPAGESIZE"; then
+fragment <<EOF
   link_info.relro = DEFAULT_LD_Z_RELRO;
+EOF
+fi
+fragment <<EOF
 }
 
 /* Try to open a dynamic archive.  This is where we know that Linux
diff --git a/ld/emultempl/scoreelf.em b/ld/emultempl/scoreelf.em
index 327ec6b..70b9a70 100644
--- a/ld/emultempl/scoreelf.em
+++ b/ld/emultempl/scoreelf.em
@@ -40,7 +40,13 @@ gld${EMULATION_NAME}_before_parse (void)
   config.has_shared = `if test -n "$GENERATE_SHLIB_SCRIPT" ; then echo TRUE ; else echo FALSE ; fi`;
   config.separate_code = `if test "x${SEPARATE_CODE}" = xyes ; then echo TRUE ; else echo FALSE ; fi`;
   link_info.check_relocs_after_open_input = TRUE;
+EOF
+if test -n "$COMMONPAGESIZE"; then
+fragment <<EOF
   link_info.relro = DEFAULT_LD_Z_RELRO;
+EOF
+fi
+fragment <<EOF
 }
 
 static void