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[PATCH] tst-tlsopt-powerpc as a shared lib


On Fri, Jul 28, 2017 at 01:07:44PM +0000, Adam Conrad wrote:
> On Fri, Jul 28, 2017 at 06:32:46PM +0930, Alan Modra wrote:
> > 
> > Since tst-tlsopt-powerpc is supposed to test glibc dynamic relocation
> > processing, the body of the test ought to be put in a shared library
> > (*).  I cobbled together such a test, and TRY_STATIC_TLS works fine.
> > So, not a powerpc64 glibc bug.
> 
> Excellent.  Should I expect said cobbled test to replace tst-tlsopt-powerpc
> in glibc trunk soonish (obviously, I'll just XFAIL it for now locally).

This makes the __tls_get_addr_opt test run as a shared library, and so
actually test that DTPMOD64/DTPREL64 pairs are processed by ld.so to
support the __tls_get_adfr_opt call stub fast return.  After a
2017-01-24 patch (binutils f0158f4416) ld.bfd no longer emitted
unnecessary dynamic relocations against local thread variables,
instead setting up the __tls_index GOT entries for the call stub fast
return.  This meant tst-tlsopt-powerpc passed but did not check ld.so
relocation support.  After a 2017-07-16 patch (binutils 676ee2b5fa)
ld.bfd no longer set up the __tls_index GOT entries for the call stub
fast return, and tst-tlsopt-powerpc failed.

Compiling mod-tlsopt-powerpc.c with -DSHARED exposed a bug in
powerpc64/tls-macros.h, which defines a __TLS_GET_ADDR macro that
clashes with one defined in dl-tls.h.  The tls-macros.h version is
only used in that file, so delete it and expand.

Regression tested powerpc64le-linux.  Please verify the Makefile
changes.  The test passes with "make -j64 check", but I may well have
missed something there.

	* sysdeps/powerpc/mod-tlsopt-powerpc.c: Extract from
	tst-tlsopt-powerpc.c with function name change and no test harness.
	* sysdeps/powerpc/tst-tlsopt-powerpc.c: Remove body of test.
	Call tls_get_addr_opt_test.
	* sysdeps/powerpc/Makefile (LDFLAGS-tst-tlsopt-powerpc): Don't define.
	(modules-names): Add mod-tlsopt-powerpc.
	(mod-tlsopt-powerpc.so-no-z-defs): Define.
	(tst-tlsopt-powerpc): Depend on .so.
	* sysdeps/powerpc/powerpc64/tls-macros.h (__TLS_GET_ADDR): Don't
	define.  Expand use in TLS_GD and TLS_LD.

diff --git a/sysdeps/powerpc/Makefile b/sysdeps/powerpc/Makefile
index 0d9206b..6aa683b 100644
--- a/sysdeps/powerpc/Makefile
+++ b/sysdeps/powerpc/Makefile
@@ -8,9 +8,11 @@ sysdep-dl-routines += dl-machine hwcapinfo
 sysdep_routines += dl-machine hwcapinfo
 # extra shared linker files to link only into dl-allobjs.so
 sysdep-rtld-routines += dl-machine hwcapinfo
-# Don't optimize GD tls sequence to LE.
-LDFLAGS-tst-tlsopt-powerpc += -Wl,--no-tls-optimize
+
+modules-names += mod-tlsopt-powerpc
+mod-tlsopt-powerpc.so-no-z-defs = yes
 tests += tst-tlsopt-powerpc
+$(objpfx)tst-tlsopt-powerpc: $(objpfx)mod-tlsopt-powerpc.so
 
 ifneq (no,$(multi-arch))
 tests-static += tst-tlsifunc-static
diff --git a/sysdeps/powerpc/mod-tlsopt-powerpc.c b/sysdeps/powerpc/mod-tlsopt-powerpc.c
new file mode 100644
index 0000000..ee0db12
--- /dev/null
+++ b/sysdeps/powerpc/mod-tlsopt-powerpc.c
@@ -0,0 +1,49 @@
+/* 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);
+
+
+int
+tls_get_addr_opt_test (void)
+{
+  int result = 0;
+
+  /* Get variable using general dynamic model.  */
+  int *ap = TLS_GD (foo);
+  if (*ap != 0)
+    {
+      printf ("foo = %d\n", *ap);
+      result = 1;
+    }
+
+  tls_index *tls_arg;
+#ifdef __powerpc64__
+  register unsigned long thread_pointer __asm__ ("r13");
+  asm ("addi %0,2,foo@got@tlsgd" : "=r" (tls_arg));
+#else
+  register unsigned long thread_pointer __asm__ ("r2");
+  asm ("bcl 20,31,1f\n1:\t"
+       "mflr %0\n\t"
+       "addis %0,%0,_GLOBAL_OFFSET_TABLE_-1b@ha\n\t"
+       "addi %0,%0,_GLOBAL_OFFSET_TABLE_-1b@l\n\t"
+       "addi %0,%0,foo@got@tlsgd" : "=b" (tls_arg));
+#endif
+
+  if (tls_arg->ti_module != 0)
+    {
+      printf ("tls_index not optimized, binutils too old?\n");
+      result = 1;
+    }
+  else if (tls_arg->ti_offset + thread_pointer != (unsigned long) ap)
+    {
+      printf ("tls_index->ti_offset wrong value\n");
+      result = 1;
+    }
+
+  return result;
+}
diff --git a/sysdeps/powerpc/powerpc64/tls-macros.h b/sysdeps/powerpc/powerpc64/tls-macros.h
index 42a95ec..79a0b25 100644
--- a/sysdeps/powerpc/powerpc64/tls-macros.h
+++ b/sysdeps/powerpc/powerpc64/tls-macros.h
@@ -18,13 +18,11 @@
      __result;								      \
   })
 
-#define __TLS_GET_ADDR "__tls_get_addr"
-
 /* PowerPC64 Local Dynamic TLS access.  */
 #define TLS_LD(x)							      \
   ({ int * __result;							      \
      asm ("addi  3,2," #x "@got@tlsld\n\t"				      \
-	  "bl    " __TLS_GET_ADDR "\n\t"				      \
+	  "bl    __tls_get_addr\n\t"					      \
 	  "nop   \n\t"							      \
 	  "addis %0,3," #x "@dtprel@ha\n\t"				      \
 	  "addi  %0,%0," #x "@dtprel@l"					      \
@@ -36,7 +34,7 @@
 #define TLS_GD(x)							      \
   ({ register int *__result __asm__ ("r3");				      \
      asm ("addi  3,2," #x "@got@tlsgd\n\t"				      \
-	  "bl    " __TLS_GET_ADDR "\n\t"				      \
+	  "bl    __tls_get_addr\n\t"					      \
 	  "nop   "							      \
 	  : "=r" (__result) :						      \
 	  : __TLS_CALL_CLOBBERS);					      \
diff --git a/sysdeps/powerpc/tst-tlsopt-powerpc.c b/sysdeps/powerpc/tst-tlsopt-powerpc.c
index 8ae928a..cc682b2 100644
--- a/sysdeps/powerpc/tst-tlsopt-powerpc.c
+++ b/sysdeps/powerpc/tst-tlsopt-powerpc.c
@@ -1,51 +1,11 @@
 /* glibc 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);
-
 
 static int
 do_test (void)
 {
-  int result = 0;
-
-  /* Get variable using general dynamic model.  */
-  int *ap = TLS_GD (foo);
-  if (*ap != 0)
-    {
-      printf ("foo = %d\n", *ap);
-      result = 1;
-    }
-
-  tls_index *tls_arg;
-#ifdef __powerpc64__
-  register unsigned long thread_pointer __asm__ ("r13");
-  asm ("addi %0,2,foo@got@tlsgd" : "=r" (tls_arg));
-#else
-  register unsigned long thread_pointer __asm__ ("r2");
-  asm ("bcl 20,31,1f\n1:\t"
-       "mflr %0\n\t"
-       "addis %0,%0,_GLOBAL_OFFSET_TABLE_-1b@ha\n\t"
-       "addi %0,%0,_GLOBAL_OFFSET_TABLE_-1b@l\n\t"
-       "addi %0,%0,foo@got@tlsgd" : "=b" (tls_arg));
-#endif
-
-  if (tls_arg->ti_module != 0)
-    {
-      printf ("tls_index not optimized, binutils too old?\n");
-      result = 1;
-    }
-  else if (tls_arg->ti_offset + thread_pointer != (unsigned long) ap)
-    {
-      printf ("tls_index->ti_offset wrong value\n");
-      result = 1;
-    }
+  extern int tls_get_addr_opt_test (void);
 
-  return result;
+  return tls_get_addr_opt_test ();
 }
 
 #include <support/test-driver.c>


-- 
Alan Modra
Australia Development Lab, IBM


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