From 33c50ef42878b07ee6ead8b3f1a81d8c2c74697c Mon Sep 17 00:00:00 2001
From: Fangrui Song <maskray@google.com>
Date: Mon, 16 Aug 2021 09:59:30 -0700
Subject: [PATCH] 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>
---
 elf/Makefile                         |  4 +-
 elf/tls-macros.h                     | 25 -----------
 elf/tst-tls1.c                       | 64 +++++++++++-----------------
 elf/tst-tls2.c                       | 82 ------------------------------------
 elf/tst-tls3.c                       | 26 +++++-------
 elf/tst-tlsmod1.c                    | 24 +++++------
 elf/tst-tlsmod2.c                    |  6 +--
 elf/tst-tlsmod3.c                    |  8 ++--
 elf/tst-tlsmod4.c                    |  6 +--
 elf/tst-tlsmod5.c                    |  4 +-
 elf/tst-tlsmod6.c                    |  4 +-
 sysdeps/powerpc/mod-tlsopt-powerpc.c |  6 +--
 sysdeps/powerpc/tst-tlsifunc.c       |  4 +-
 13 files changed, 64 insertions(+), 199 deletions(-)
 delete mode 100644 elf/tls-macros.h
 delete mode 100644 elf/tst-tls2.c

diff --git a/elf/Makefile b/elf/Makefile
index d05f410..725537c 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -163,7 +163,7 @@ tests-static-normal := tst-array1-static tst-array5-static \
 	       tst-single_threaded-static tst-single_threaded-pthread-static \
 	       tst-dst-static tst-getauxval-static
 
-tests-static-internal := tst-tls1-static tst-tls2-static \
+tests-static-internal := tst-tls1-static \
 	       tst-ptrguard1-static tst-stackguard1-static \
 	       tst-tls1-static-non-pie
 
@@ -183,7 +183,7 @@ endif
 tests := tst-tls9 tst-leaks1 \
 	tst-array1 tst-array2 tst-array3 tst-array4 tst-array5 \
 	tst-auxv tst-stringtable
-tests-internal := tst-tls1 tst-tls2 $(tests-static-internal)
+tests-internal := tst-tls1 $(tests-static-internal)
 tests-static := $(tests-static-normal) $(tests-static-internal)
 
 ifeq (yes,$(build-shared))
diff --git a/elf/tls-macros.h b/elf/tls-macros.h
deleted file mode 100644
index e25e33b..0000000
--- a/elf/tls-macros.h
+++ /dev/null
@@ -1,25 +0,0 @@
-/* Macros to support TLS testing in times of missing compiler support.  */
-
-#define COMMON_INT_DEF(x) \
-  asm (".tls_common " #x ",4,4")
-/* XXX Until we get compiler support we don't need declarations.  */
-#define COMMON_INT_DECL(x)
-
-/* XXX This definition will probably be machine specific, too.  */
-#define VAR_INT_DEF(x) \
-  asm (".section .tdata\n\t"						      \
-       ".globl " #x "\n"						      \
-       ".balign 4\n"							      \
-       #x ":\t.long 0\n\t"						      \
-       ".size " #x ",4\n\t"						      \
-       ".previous")
-/* XXX Until we get compiler support we don't need declarations.  */
-#define VAR_INT_DECL(x)
-
-#include_next <tls-macros.h>
-
-  /* XXX Each architecture must have its own asm for now.  */
-#if !defined TLS_LE || !defined TLS_IE \
-      || !defined TLS_LD || !defined TLS_GD
-# error "No support for this architecture so far."
-#endif
diff --git a/elf/tst-tls1.c b/elf/tst-tls1.c
index c31da56..b341221 100644
--- a/elf/tst-tls1.c
+++ b/elf/tst-tls1.c
@@ -1,13 +1,14 @@
 /* glibc test for TLS in ld.so.  */
 #include <stdio.h>
 
-#include "tls-macros.h"
-
-
-/* Two common 'int' variables in TLS.  */
-COMMON_INT_DEF(foo);
-COMMON_INT_DEF(bar);
 
+__thread int foo, bar __attribute__ ((tls_model("local-exec")));
+extern __thread int foo_gd asm ("foo") __attribute__ ((tls_model("global-dynamic")));
+extern __thread int foo_ld asm ("foo") __attribute__ ((tls_model("local-dynamic")));
+extern __thread int foo_ie asm ("foo") __attribute__ ((tls_model("initial-exec")));
+extern __thread int bar_gd asm ("bar") __attribute__ ((tls_model("global-dynamic")));
+extern __thread int bar_ld asm ("bar") __attribute__ ((tls_model("local-dynamic")));
+extern __thread int bar_ie asm ("bar") __attribute__ ((tls_model("initial-exec")));
 
 static int
 do_test (void)
@@ -18,63 +19,48 @@ do_test (void)
 
   /* Set the variable using the local exec model.  */
   puts ("set bar to 1 (LE)");
-  ap = TLS_LE (bar);
-  *ap = 1;
+  bar = 1;
 
 
   /* Get variables using initial exec model.  */
   fputs ("get sum of foo and bar (IE)", stdout);
-  ap = TLS_IE (foo);
-  bp = TLS_IE (bar);
+  ap = &foo_ie;
+  bp = &bar_ie;
   printf (" = %d\n", *ap + *bp);
   result |= *ap + *bp != 1;
-  if (*ap != 0)
-    {
-      printf ("foo = %d\n", *ap);
-      result = 1;
-    }
-  if (*bp != 1)
+  if (*ap != 0 || *bp != 1)
     {
-      printf ("bar = %d\n", *bp);
+      printf ("foo = %d\nbar = %d\n", *ap, *bp);
       result = 1;
     }
 
 
-  /* Get variables using local dynamic model.  */
-  fputs ("get sum of foo and bar (LD)", stdout);
-  ap = TLS_LD (foo);
-  bp = TLS_LD (bar);
+  /* Get variables using local dynamic model or TLSDESC.  */
+  fputs ("get sum of foo and bar (LD or TLSDESC)", stdout);
+  ap = &foo_ld;
+  bp = &bar_ld;
   printf (" = %d\n", *ap + *bp);
   result |= *ap + *bp != 1;
-  if (*ap != 0)
-    {
-      printf ("foo = %d\n", *ap);
-      result = 1;
-    }
-  if (*bp != 1)
+  if (*ap != 0 || *bp != 1)
     {
-      printf ("bar = %d\n", *bp);
+      printf ("foo = %d\nbar = %d\n", *ap, *bp);
       result = 1;
     }
 
 
-  /* Get variables using generic dynamic model.  */
-  fputs ("get sum of foo and bar (GD)", stdout);
-  ap = TLS_GD (foo);
-  bp = TLS_GD (bar);
+  /* Get variables using general dynamic model or TLSDESC.  */
+  fputs ("get sum of foo and bar (GD or TLSDESC)", stdout);
+  ap = &foo_gd;
+  bp = &bar_gd;
   printf (" = %d\n", *ap + *bp);
   result |= *ap + *bp != 1;
-  if (*ap != 0)
-    {
-      printf ("foo = %d\n", *ap);
-      result = 1;
-    }
-  if (*bp != 1)
+  if (*ap != 0 || *bp != 1)
     {
-      printf ("bar = %d\n", *bp);
+      printf ("foo = %d\nbar = %d\n", *ap, *bp);
       result = 1;
     }
 
+
   return result;
 }
 
diff --git a/elf/tst-tls2.c b/elf/tst-tls2.c
deleted file mode 100644
index 963b8d6..0000000
--- a/elf/tst-tls2.c
+++ /dev/null
@@ -1,82 +0,0 @@
-/* glibc test for TLS in ld.so.  */
-#include <stdio.h>
-
-#include "tls-macros.h"
-
-
-/* Two 'int' variables in TLS.  */
-VAR_INT_DEF(foo);
-VAR_INT_DEF(bar);
-
-
-static int
-do_test (void)
-{
-  int result = 0;
-  int *ap, *bp;
-
-
-  /* Set the variable using the local exec model.  */
-  puts ("set bar to 1 (LE)");
-  ap = TLS_LE (bar);
-  *ap = 1;
-
-
-  /* Get variables using initial exec model.  */
-  fputs ("get sum of foo and bar (IE)", stdout);
-  ap = TLS_IE (foo);
-  bp = TLS_IE (bar);
-  printf (" = %d\n", *ap + *bp);
-  result |= *ap + *bp != 1;
-  if (*ap != 0)
-    {
-      printf ("foo = %d\n", *ap);
-      result = 1;
-    }
-  if (*bp != 1)
-    {
-      printf ("bar = %d\n", *bp);
-      result = 1;
-    }
-
-
-  /* Get variables using local dynamic model.  */
-  fputs ("get sum of foo and bar (LD)", stdout);
-  ap = TLS_LD (foo);
-  bp = TLS_LD (bar);
-  printf (" = %d\n", *ap + *bp);
-  result |= *ap + *bp != 1;
-  if (*ap != 0)
-    {
-      printf ("foo = %d\n", *ap);
-      result = 1;
-    }
-  if (*bp != 1)
-    {
-      printf ("bar = %d\n", *bp);
-      result = 1;
-    }
-
-
-  /* Get variables using generic dynamic model.  */
-  fputs ("get sum of foo and bar (GD)", stdout);
-  ap = TLS_GD (foo);
-  bp = TLS_GD (bar);
-  printf (" = %d\n", *ap + *bp);
-  result |= *ap + *bp != 1;
-  if (*ap != 0)
-    {
-      printf ("foo = %d\n", *ap);
-      result = 1;
-    }
-  if (*bp != 1)
-    {
-      printf ("bar = %d\n", *bp);
-      result = 1;
-    }
-
-  return result;
-}
-
-
-#include <support/test-driver.c>
diff --git a/elf/tst-tls3.c b/elf/tst-tls3.c
index 7e0abb4..222b179 100644
--- a/elf/tst-tls3.c
+++ b/elf/tst-tls3.c
@@ -1,13 +1,12 @@
 /* glibc test for TLS in ld.so.  */
 #include <stdio.h>
 
-#include "tls-macros.h"
 
-
-/* One define int variable, two externs.  */
-COMMON_INT_DECL(foo);
-VAR_INT_DECL(bar);
-VAR_INT_DEF(baz);
+__thread int foo, bar __attribute__ ((tls_model("initial-exec")));
+__thread int baz __attribute__ ((tls_model("local-exec")));
+extern __thread int foo_gd __attribute__ ((alias("foo"), tls_model("global-dynamic")));
+extern __thread int bar_gd __attribute__ ((alias("bar"), tls_model("global-dynamic")));
+extern __thread int baz_ld __attribute__ ((alias("baz"), tls_model("local-dynamic")));
 
 
 extern int in_dso (void);
@@ -22,23 +21,20 @@ do_test (void)
 
   /* Set the variable using the local exec model.  */
   puts ("set baz to 3 (LE)");
-  ap = TLS_LE (baz);
-  *ap = 3;
+  baz = 3;
 
 
   /* Get variables using initial exec model.  */
   puts ("set variables foo and bar (IE)");
-  ap = TLS_IE (foo);
-  *ap = 1;
-  bp = TLS_IE (bar);
-  *bp = 2;
+  foo = 1;
+  bar = 2;
 
 
   /* Get variables using local dynamic model.  */
   fputs ("get sum of foo, bar (GD) and baz (LD)", stdout);
-  ap = TLS_GD (foo);
-  bp = TLS_GD (bar);
-  cp = TLS_LD (baz);
+  ap = &foo_gd;
+  bp = &bar_gd;
+  cp = &baz_ld;
   printf (" = %d\n", *ap + *bp + *cp);
   result |= *ap + *bp + *cp != 6;
   if (*ap != 1)
diff --git a/elf/tst-tlsmod1.c b/elf/tst-tlsmod1.c
index 8d91567..a448c4d 100644
--- a/elf/tst-tlsmod1.c
+++ b/elf/tst-tlsmod1.c
@@ -1,12 +1,12 @@
 #include <stdio.h>
 
-#include "tls-macros.h"
 
+__thread int foo, bar __attribute__ ((tls_model("global-dynamic")));
+extern __thread int baz __attribute__ ((tls_model("global-dynamic")));
+extern __thread int foo_ie asm ("foo") __attribute__ ((tls_model("initial-exec")));
+extern __thread int bar_ie asm ("bar") __attribute__ ((tls_model("initial-exec")));
+extern __thread int baz_ie asm ("baz") __attribute__ ((tls_model("initial-exec")));
 
-/* One define int variable, two externs.  */
-COMMON_INT_DEF(foo);
-VAR_INT_DEF(bar);
-VAR_INT_DECL(baz);
 
 extern int in_dso (void);
 
@@ -19,8 +19,8 @@ in_dso (void)
   /* Get variables using initial exec model.  */
   fputs ("get sum of foo and bar (IE)", stdout);
   asm ("" ::: "memory");
-  ap = TLS_IE (foo);
-  bp = TLS_IE (bar);
+  ap = &foo_ie;
+  bp = &bar_ie;
   printf (" = %d\n", *ap + *bp);
   result |= *ap + *bp != 3;
   if (*ap != 1)
@@ -35,11 +35,11 @@ in_dso (void)
     }
 
 
-  /* Get variables using generic dynamic model.  */
-  fputs ("get sum of foo and bar and baz (GD)", stdout);
-  ap = TLS_GD (foo);
-  bp = TLS_GD (bar);
-  cp = TLS_GD (baz);
+  /* Get variables using generic dynamic model or TLSDESC.  */
+  fputs ("get sum of foo and bar and baz (GD or TLSDESC)", stdout);
+  ap = &foo;
+  bp = &bar;
+  cp = &baz;
   printf (" = %d\n", *ap + *bp + *cp);
   result |= *ap + *bp + *cp != 6;
   if (*ap != 1)
diff --git a/elf/tst-tlsmod2.c b/elf/tst-tlsmod2.c
index 40eb140..3223fe4 100644
--- a/elf/tst-tlsmod2.c
+++ b/elf/tst-tlsmod2.c
@@ -1,9 +1,7 @@
 #include <stdio.h>
 
-#include "tls-macros.h"
 
-
-COMMON_INT_DEF(foo);
+__thread int foo;
 
 
 int
@@ -15,7 +13,7 @@ in_dso (int n, int *caller_foop)
   puts ("foo");			/* Make sure PLT is used before macros.  */
   asm ("" ::: "memory");
 
-  foop = TLS_GD (foo);
+  foop = &foo;
 
   if (caller_foop != NULL && foop != caller_foop)
     {
diff --git a/elf/tst-tlsmod3.c b/elf/tst-tlsmod3.c
index 6d186c4..d6e7498 100644
--- a/elf/tst-tlsmod3.c
+++ b/elf/tst-tlsmod3.c
@@ -1,10 +1,10 @@
 #include <stdio.h>
 
-#include "tls-macros.h"
 
 extern int in_dso (int n, int *caller_foop);
 
-COMMON_INT_DEF(comm_n);
+extern __thread int foo;
+__thread int comm_n;
 
 
 
@@ -20,8 +20,8 @@ in_dso2 (void)
   puts ("foo");			/* Make sure PLT is used before macros.  */
   asm ("" ::: "memory");
 
-  foop = TLS_GD (foo);
-  np = TLS_GD (comm_n);
+  foop = &foo;
+  np = &comm_n;
 
   if (n != *np)
     {
diff --git a/elf/tst-tlsmod4.c b/elf/tst-tlsmod4.c
index 86889aa..f38919a 100644
--- a/elf/tst-tlsmod4.c
+++ b/elf/tst-tlsmod4.c
@@ -1,9 +1,7 @@
 #include <stdio.h>
 
-#include "tls-macros.h"
 
-
-COMMON_INT_DEF(baz);
+__thread int baz;
 
 
 int
@@ -15,7 +13,7 @@ in_dso (int n, int *caller_bazp)
   puts ("foo");			/* Make sure PLT is used before macros.  */
   asm ("" ::: "memory");
 
-  bazp = TLS_GD (baz);
+  bazp = &baz;
 
   if (caller_bazp != NULL && bazp != caller_bazp)
     {
diff --git a/elf/tst-tlsmod5.c b/elf/tst-tlsmod5.c
index a97c7e5..3f39c5b 100644
--- a/elf/tst-tlsmod5.c
+++ b/elf/tst-tlsmod5.c
@@ -1,3 +1 @@
-#include "tls-macros.h"
-
-COMMON_INT_DEF(foo);
+__thread int foo;
diff --git a/elf/tst-tlsmod6.c b/elf/tst-tlsmod6.c
index e968596..7b3571f 100644
--- a/elf/tst-tlsmod6.c
+++ b/elf/tst-tlsmod6.c
@@ -1,3 +1 @@
-#include "tls-macros.h"
-
-COMMON_INT_DEF(bar);
+__thread int bar;
diff --git a/sysdeps/powerpc/mod-tlsopt-powerpc.c b/sysdeps/powerpc/mod-tlsopt-powerpc.c
index ee0db12..2a82e53 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 3095d41..c8c0bad 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
-- 
1.8.3.1

