diff mbox series

[v2] elf: Drop elf/tls-macros.h in favor of __thread and tls_model attributes [BZ #28152] [BZ #28205]

Message ID 20210812175511.2736422-1-maskray@google.com
State New
Headers show
Series [v2] elf: Drop elf/tls-macros.h in favor of __thread and tls_model attributes [BZ #28152] [BZ #28205] | expand

Commit Message

Fangrui Song Aug. 12, 2021, 5:55 p.m. UTC 
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 which is 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.

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 x86_64-linux-gnu and aarch64-linux-gnu.
---
 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 +--
 11 files changed, 68 insertions(+), 185 deletions(-)
 delete mode 100644 elf/tls-macros.h
 delete mode 100644 elf/tst-tls2.c

Comments

Szabolcs Nagy Aug. 12, 2021, 6:10 p.m. UTC | #1 
The 08/12/2021 10:55, Fangrui Song via Libc-alpha wrote:
> 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 which is 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.
> 
> 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 x86_64-linux-gnu and aarch64-linux-gnu.

it seems tls-macros.h stuff is used by some target
specific tests (on powerpc)

ideally those would be updated too and all target
tls-macros.h removed.

(if you don't want to deal with powerpc then i
think you need to keep tls-macros.h, the rest of
the patch still makes aarch64 work with lld.)

> diff --git a/elf/tst-tls1.c b/elf/tst-tls1.c
> index c31da56ce9..81bd3468d5 100644
> --- a/elf/tst-tls1.c
> +++ b/elf/tst-tls1.c
> @@ -4,10 +4,13 @@
>  #include "tls-macros.h"

is this still needed?

>  
>  
> -/* 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)
Fangrui Song Aug. 12, 2021, 6:38 p.m. UTC | #2 
On Thu, Aug 12, 2021 at 11:11 AM Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
>
> The 08/12/2021 10:55, Fangrui Song via Libc-alpha wrote:
> > 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 which is 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.
> >
> > 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 x86_64-linux-gnu and aarch64-linux-gnu.
>
> it seems tls-macros.h stuff is used by some target
> specific tests (on powerpc)
>
> ideally those would be updated too and all target
> tls-macros.h removed.
>
> (if you don't want to deal with powerpc then i
> think you need to keep tls-macros.h, the rest of
> the patch still makes aarch64 work with lld.)

Thanks for catching this.
I have updated sysdeps/powerpc/ tests in v3 and found a ppc64le
machine to test it.

> > diff --git a/elf/tst-tls1.c b/elf/tst-tls1.c
> > index c31da56ce9..81bd3468d5 100644
> > --- a/elf/tst-tls1.c
> > +++ b/elf/tst-tls1.c
> > @@ -4,10 +4,13 @@
> >  #include "tls-macros.h"
>
> is this still needed?

Yes, I still keep a TLS_GD reference.
Otherwise aarch64 would lose traditional TLS GD coverage.

After we add optional -mtls-dialect={gnu2,trad} tests to Makefile,
this can be removed without coverage degradation.

> >
> >
> > -/* 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)
diff mbox series

Patch

diff --git a/elf/Makefile b/elf/Makefile
index d05f410592..725537c40b 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 e25e33b0f0..0000000000
--- 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 c31da56ce9..81bd3468d5 100644
--- a/elf/tst-tls1.c
+++ b/elf/tst-tls1.c
@@ -4,10 +4,13 @@ 
 #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)
@@ -18,62 +21,61 @@  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)
+  if (*ap != 0 || *bp != 1)
     {
-      printf ("foo = %d\n", *ap);
-      result = 1;
-    }
-  if (*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)
+  if (*ap != 0 || *bp != 1)
     {
-      printf ("foo = %d\n", *ap);
+      printf ("foo = %d\nbar = %d\n", *ap, *bp);
       result = 1;
     }
-  if (*bp != 1)
+
+
+  /* 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 || *bp != 1)
     {
-      printf ("bar = %d\n", *bp);
+      printf ("foo = %d\nbar = %d\n", *ap, *bp);
       result = 1;
     }
 
 
-  /* Get variables using generic dynamic model.  */
+#ifdef TLS_GD
+  /* Get variables using traditional 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)
+  if (*ap != 0 || *bp != 1)
     {
-      printf ("foo = %d\n", *ap);
-      result = 1;
-    }
-  if (*bp != 1)
-    {
-      printf ("bar = %d\n", *bp);
+      printf ("foo = %d\nbar = %d\n", *ap, *bp);
       result = 1;
     }
+#endif
 
   return result;
 }
diff --git a/elf/tst-tls2.c b/elf/tst-tls2.c
deleted file mode 100644
index 963b8d6c88..0000000000
--- 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 7e0abb4c58..222b179626 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 8d9156791b..a448c4dc37 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 40eb1407f8..3223fe494b 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 6d186c47ee..d6e7498fd8 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 86889aac7e..f38919a8a9 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 a97c7e5e0c..3f39c5bdb7 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 e968596dd4..7b3571f428 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;