[PATCH v2] aarch64: Skip traditional GD/LD TLS which are unsupported by Clang and LLD [BZ #28205]
Fangrui Song
maskray@google.com
Tue Aug 10 21:02:47 GMT 2021
TLSDESC is the default on aarch64. Clang doesn't support
-mtls-dialect=trad. Its integrated assembler doesn't support the
marker. LLD's doesn't support R_AARCH64_TLSGD_*/R_AARCH64_TLSLD_*
relocations. Just skip the tests.
With https://sourceware.org/pipermail/libc-alpha/2021-August/129966.html
("aarch64: Make elf_machine_{load_address, dynamic} robust [BZ #28203]"),
if we allow LLD in configure.ac,
`make check` test results of LLD are on par with GNU ld.
---
config.h.in | 3 +++
elf/tst-tls1.c | 7 +++++--
elf/tst-tls2.c | 6 ++++--
elf/tst-tls3.c | 8 ++++----
elf/tst-tlsmod1.c | 6 ++++--
elf/tst-tlsmod2.c | 4 +++-
elf/tst-tlsmod3.c | 5 ++++-
elf/tst-tlsmod4.c | 4 +++-
sysdeps/aarch64/configure | 30 ++++++++++++++++++++++++++++++
sysdeps/aarch64/configure.ac | 18 ++++++++++++++++++
10 files changed, 78 insertions(+), 13 deletions(-)
diff --git a/config.h.in b/config.h.in
index 0d92504f65..7dcce4d3a4 100644
--- a/config.h.in
+++ b/config.h.in
@@ -198,6 +198,9 @@
/* Define if CC supports attribute retain. */
#undef HAVE_GNU_RETAIN
+/* Define if CC and LD support traditional TLS GD/LD models. */
+#define HAVE_TRAD_TLS 1
+
/* Define to 1 if the assembler needs intermediate aliases to define
multiple symbol versions for one symbol. */
#define SYMVER_NEEDS_ALIAS 0
diff --git a/elf/tst-tls1.c b/elf/tst-tls1.c
index c31da56ce9..57d5ea2485 100644
--- a/elf/tst-tls1.c
+++ b/elf/tst-tls1.c
@@ -39,7 +39,8 @@ do_test (void)
result = 1;
}
-
+ /* Clang and LLD do not support traditional GD/LD TLS on aarch64. */
+#ifdef HAVE_TRAD_TLS
/* Get variables using local dynamic model. */
fputs ("get sum of foo and bar (LD)", stdout);
ap = TLS_LD (foo);
@@ -56,8 +57,9 @@ do_test (void)
printf ("bar = %d\n", *bp);
result = 1;
}
+#endif
-
+#ifdef HAVE_TRAD_TLS
/* Get variables using generic dynamic model. */
fputs ("get sum of foo and bar (GD)", stdout);
ap = TLS_GD (foo);
@@ -74,6 +76,7 @@ do_test (void)
printf ("bar = %d\n", *bp);
result = 1;
}
+#endif
return result;
}
diff --git a/elf/tst-tls2.c b/elf/tst-tls2.c
index 963b8d6c88..c9dcc084e3 100644
--- a/elf/tst-tls2.c
+++ b/elf/tst-tls2.c
@@ -39,7 +39,7 @@ do_test (void)
result = 1;
}
-
+#ifdef HAVE_TRAD_TLS
/* Get variables using local dynamic model. */
fputs ("get sum of foo and bar (LD)", stdout);
ap = TLS_LD (foo);
@@ -56,8 +56,9 @@ do_test (void)
printf ("bar = %d\n", *bp);
result = 1;
}
+#endif
-
+#ifdef HAVE_TRAD_TLS
/* Get variables using generic dynamic model. */
fputs ("get sum of foo and bar (GD)", stdout);
ap = TLS_GD (foo);
@@ -74,6 +75,7 @@ do_test (void)
printf ("bar = %d\n", *bp);
result = 1;
}
+#endif
return result;
}
diff --git a/elf/tst-tls3.c b/elf/tst-tls3.c
index 7e0abb4c58..6f2e144a7f 100644
--- a/elf/tst-tls3.c
+++ b/elf/tst-tls3.c
@@ -17,8 +17,7 @@ static int
do_test (void)
{
int result = 0;
- int *ap, *bp, *cp;
-
+ int *ap, *bp;
/* Set the variable using the local exec model. */
puts ("set baz to 3 (LE)");
@@ -33,7 +32,8 @@ do_test (void)
bp = TLS_IE (bar);
*bp = 2;
-
+#ifdef HAVE_TRAD_TLS
+ int *cp;
/* Get variables using local dynamic model. */
fputs ("get sum of foo, bar (GD) and baz (LD)", stdout);
ap = TLS_GD (foo);
@@ -56,7 +56,7 @@ do_test (void)
printf ("baz = %d\n", *cp);
result = 1;
}
-
+#endif
result |= in_dso ();
diff --git a/elf/tst-tlsmod1.c b/elf/tst-tlsmod1.c
index 8d9156791b..9f48e36af4 100644
--- a/elf/tst-tlsmod1.c
+++ b/elf/tst-tlsmod1.c
@@ -14,7 +14,7 @@ int
in_dso (void)
{
int result = 0;
- int *ap, *bp, *cp;
+ int *ap, *bp;
/* Get variables using initial exec model. */
fputs ("get sum of foo and bar (IE)", stdout);
@@ -34,7 +34,8 @@ in_dso (void)
result = 1;
}
-
+#ifdef HAVE_TRAD_TLS
+ int *cp;
/* Get variables using generic dynamic model. */
fputs ("get sum of foo and bar and baz (GD)", stdout);
ap = TLS_GD (foo);
@@ -57,6 +58,7 @@ in_dso (void)
printf ("baz = %d\n", *cp);
result = 1;
}
+#endif
return result;
}
diff --git a/elf/tst-tlsmod2.c b/elf/tst-tlsmod2.c
index 40eb1407f8..78578ebcc2 100644
--- a/elf/tst-tlsmod2.c
+++ b/elf/tst-tlsmod2.c
@@ -9,9 +9,10 @@ COMMON_INT_DEF(foo);
int
in_dso (int n, int *caller_foop)
{
- int *foop;
int result = 0;
+#ifdef HAVE_TRAD_TLS
+ int *foop;
puts ("foo"); /* Make sure PLT is used before macros. */
asm ("" ::: "memory");
@@ -29,6 +30,7 @@ in_dso (int n, int *caller_foop)
}
*foop = 16;
+#endif
return result;
}
diff --git a/elf/tst-tlsmod3.c b/elf/tst-tlsmod3.c
index 6d186c47ee..d9f17dbb6f 100644
--- a/elf/tst-tlsmod3.c
+++ b/elf/tst-tlsmod3.c
@@ -12,8 +12,10 @@ COMMON_INT_DEF(comm_n);
int
in_dso2 (void)
{
- int *foop;
int result = 0;
+
+#ifdef HAVE_TRAD_TLS
+ int *foop;
static int n;
int *np;
@@ -32,6 +34,7 @@ in_dso2 (void)
result |= in_dso (*foop = 42 + n++, foop);
*foop = 16;
+#endif
return result;
}
diff --git a/elf/tst-tlsmod4.c b/elf/tst-tlsmod4.c
index 86889aac7e..27baaaf501 100644
--- a/elf/tst-tlsmod4.c
+++ b/elf/tst-tlsmod4.c
@@ -9,9 +9,10 @@ COMMON_INT_DEF(baz);
int
in_dso (int n, int *caller_bazp)
{
- int *bazp;
int result = 0;
+#ifdef HAVE_TRAD_TLS
+ int *bazp;
puts ("foo"); /* Make sure PLT is used before macros. */
asm ("" ::: "memory");
@@ -29,6 +30,7 @@ in_dso (int n, int *caller_bazp)
}
*bazp = 16;
+#endif
return result;
}
diff --git a/sysdeps/aarch64/configure b/sysdeps/aarch64/configure
index 4c1fac49f3..eb62e68010 100644
--- a/sysdeps/aarch64/configure
+++ b/sysdeps/aarch64/configure
@@ -332,3 +332,33 @@ if test $libc_cv_aarch64_sve_asm = yes; then
$as_echo "#define HAVE_AARCH64_SVE_ASM 1" >>confdefs.h
fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for -mtls-dialect=trad" >&5
+$as_echo_n "checking for -mtls-dialect=trad... " >&6; }
+if ${libc_cv_aarch64_trad_tls+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ cat > conftest.c <<EOF
+extern __thread int i;
+void foo (void) { i = 10; }
+EOF
+ if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -fPIC
+ -mtls-dialect=trad -shared -o conftest.so conftest.c'
+ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+ test $ac_status = 0; }; }
+ then
+ libc_cv_aarch64_trad_tls=yes
+ else
+ libc_cv_aarch64_trad_tls=no
+ fi
+ rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_aarch64_trad_tls" >&5
+$as_echo "$libc_cv_aarch64_trad_tls" >&6; }
+if test $libc_cv_aarch64_trad_tls = no; then
+ $as_echo "#define HAVE_TRAD_TLS 0" >>confdefs.h
+
+fi
diff --git a/sysdeps/aarch64/configure.ac b/sysdeps/aarch64/configure.ac
index 3347c13fa1..6d3b412acc 100644
--- a/sysdeps/aarch64/configure.ac
+++ b/sysdeps/aarch64/configure.ac
@@ -105,3 +105,21 @@ rm -f conftest*])
if test $libc_cv_aarch64_sve_asm = yes; then
AC_DEFINE(HAVE_AARCH64_SVE_ASM)
fi
+
+# Check if both CC and LD support traditional TLS GD/LD models.
+AC_CACHE_CHECK([for -mtls-dialect=trad], libc_cv_aarch64_trad_tls, [dnl
+cat > conftest.c <<EOF
+extern __thread int i;
+void foo (void) { i = 10; }
+EOF
+ if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -fPIC
+ -mtls-dialect=trad -shared -o conftest.so conftest.c])
+ then
+ libc_cv_aarch64_trad_tls=yes
+ else
+ libc_cv_aarch64_trad_tls=no
+ fi
+ rm -f conftest*])
+if test $libc_cv_aarch64_trad_tls = no; then
+ AC_DEFINE(HAVE_TRAD_TLS, 0)
+fi
--
2.32.0.605.g8dce9f2422-goog
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