elf: Drop elf/tls-macros.h in favor of __thread and tls_model attributes [BZ #28152] [BZ #28205]

elf/tls-macros.h was added for TLS testing when GCC did not support
__thread. __thread and tls_model attributes are mature now and have been
used by many newer tests.

Also delete tst-tls2.c which tests .tls_common (unused by modern GCC and
unsupported by Clang/LLD). .tls_common and .tbss definition are almost
identical after linking, so the runtime test doesn't add additional
coverage.  Assembler and linker tests should be on the binutils side.

When LLD 13.0.0 is allowed in configure.ac
(https://sourceware.org/pipermail/libc-alpha/2021-August/129866.html),
`make check` result is on par with glibc built with GNU ld on aarch64
and x86_64.

As a future clean-up, TLS_GD/TLS_LD/TLS_IE/TLS_IE macros can be removed from
sysdeps/*/tls-macros.h. We can add optional -mtls-dialect={gnu2,trad}
tests to ensure coverage.

Tested on aarch64-linux-gnu, powerpc64le-linux-gnu, and x86_64-linux-gnu.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>

2 files changed, 4 insertions, 6 deletions

diff --git a/sysdeps/powerpc/mod-tlsopt-powerpc.c b/sysdeps/powerpc/mod-tlsopt-powerpc.c
index ee0db12a73..2a82e53baf 100644
--- a/sysdeps/powerpc/mod-tlsopt-powerpc.c
+++ b/sysdeps/powerpc/mod-tlsopt-powerpc.c
@@ -1,11 +1,9 @@
 /* shared library to test for __tls_get_addr optimization.  */
 #include <stdio.h>
 
-#include "../../elf/tls-macros.h"
 #include "dl-tls.h"
 
-/* common 'int' variable in TLS.  */
-COMMON_INT_DEF(foo);
+__thread int foo __attribute__ ((tls_model("global-dynamic")));
 
 
 int
@@ -14,7 +12,7 @@ tls_get_addr_opt_test (void)
   int result = 0;
 
   /* Get variable using general dynamic model.  */
-  int *ap = TLS_GD (foo);
+  int *ap = &foo;
   if (*ap != 0)
     {
       printf ("foo = %d\n", *ap);
diff --git a/sysdeps/powerpc/tst-tlsifunc.c b/sysdeps/powerpc/tst-tlsifunc.c
index 3095d41a68..c8c0bada45 100644
--- a/sysdeps/powerpc/tst-tlsifunc.c
+++ b/sysdeps/powerpc/tst-tlsifunc.c
@@ -21,9 +21,9 @@
 #include <stdint.h>
 #include <inttypes.h>
 #include <libc-symbols.h>
-#include <tls-macros.h>
 
 __thread int bar;
+extern __thread int bar_gd asm ("bar") __attribute__ ((tls_model("global-dynamic")));
 static int *bar_ptr = NULL;
 
 static uint32_t resolver_platform = 0;
@@ -57,7 +57,7 @@ get_platform (void)
 void
 init_foo (void)
 {
-  bar_ptr = TLS_GD (bar);
+  bar_ptr = &bar_gd;
 }
 
 int