[PATCH] Re: Glibc broken for ia64

[Jakub Jelinek <jakub at redhat dot com>]

On Tue, Jan 14, 2003 at 06:23:08PM +0100, Jakub Jelinek wrote:
> On Tue, Jan 14, 2003 at 04:54:17PM +0100, Andreas Schwab wrote:
> > Jakub Jelinek <jakub@redhat.com> writes:
> > 
> > |> On Tue, Jan 14, 2003 at 04:40:44PM +0100, Andreas Schwab wrote:
> > |> > Current CVS is broken on ia64.  It is crashing after __errno_location has
> > |> > handed out a bogus pointer, which is due to the thread register not
> > |> > properly initialized.  I tried with the patch below, but then
> > |> > linuxthreads does not work at all.  I also tried --without-__thread, but
> > |> > that did not help.
> > |> 
> > |> --with-tls or --without-tls?
> > 
> > The latter (implicitly, no support in binutils).
> 
> The following patch could fix it, haven't tested it yet though.

Ok, testing revealed a problem.
With
#ifdef USE_TLS
MULTIPLE_THREADS_OFFSET offsetof (struct _pthread_descr_struct, p_header.data.multiple_threads) - sizeof (struct _pthread_descr_struct)
#else
MULTIPLE_THREADS_OFFSET offsetof (tcbhead_t, multiple_threads)
#endif
in the .sym file we try to compile
#ifdef USE_TLS
void dummy(void) {
asm ("@@@name@@@MULTIPLE_THREADS_OFFSET@@@value@@@%0@@@end@@@" : : "i" (something));
#else
asm ("@@@name@@@MULTIPLE_THREADS_OFFSET@@@value@@@%0@@@end@@@" : : "i" (somethingelse));
#endif
}
which means a syntax error if USE_TLS is not defined.
This can be either solved by adding some dummy never used define, say
TCB_OFFSET_DUMMY 0
#ifdef USE_TLS
...
or by the following change (which I've bootstrapped/regtested on IA-64
with both --with-tls --without-__thread and --without-tls --without-__thread).

2003-01-15  Jakub Jelinek  <jakub@redhat.com>

	* scripts/gen-as-const.awk: Pass // comments through after starting
	dummy function.
linuxthreads/
	* sysdeps/ia64/tls.h (tcbhead_t): Use the TLS ABI required layout
	if USE_TLS only.
	(NONTLS_INIT_TP): Revert last change.
	* sysdeps/ia64/tcb-offsets.sym (MULTIPLE_THREADS_OFFSET): Define to
	offsetof (tcbhead_t, multiple_threads) if USE_TLS not defined.

--- libc/linuxthreads/sysdeps/ia64/tls.h.jj	2003-01-13 13:57:10.000000000 +0100
+++ libc/linuxthreads/sysdeps/ia64/tls.h	2003-01-14 18:12:27.000000000 +0100
@@ -32,13 +32,6 @@ typedef union dtv
   void *pointer;
 } dtv_t;
 
-
-typedef struct
-{
-  dtv_t *dtv;
-  void *private;
-} tcbhead_t;
-
 #else /* __ASSEMBLER__ */
 # include <tcb-offsets.h>
 #endif /* __ASSEMBLER__ */
@@ -49,6 +42,13 @@ typedef struct
 # define USE_TLS        1
 
 # ifndef __ASSEMBLER__
+
+typedef struct
+{
+  dtv_t *dtv;
+  void *private;
+} tcbhead_t;
+
 /* This is the size of the initial TCB.  */
 #  define TLS_INIT_TCB_SIZE sizeof (tcbhead_t)
 
@@ -106,14 +106,22 @@ typedef struct
 #else
 
 # ifndef __ASSEMBLER__
+
+typedef struct
+{
+  void *tcb;
+  dtv_t *dtv;
+  void *self;
+  int multiple_threads;
+} tcbhead_t;
+
 /* Get the thread descriptor definition.  */
 #  include <linuxthreads/descr.h>
 
 #  define NONTLS_INIT_TP \
   do { 									\
-    static struct _pthread_descr_struct nontls_init_tp			\
-      = { .p_header.data.multiple_threads = 0 };			\
-    __thread_self = ((__typeof (__thread_self)) &nontls_init_tp) + 1;	\
+    static const tcbhead_t nontls_init_tp = { .multiple_threads = 0 };	\
+    __thread_self = (__typeof (__thread_self)) &nontls_init_tp;		\
   } while (0)
 
 #endif
--- libc/linuxthreads/sysdeps/ia64/tcb-offsets.sym.jj	2003-01-13 13:57:10.000000000 +0100
+++ libc/linuxthreads/sysdeps/ia64/tcb-offsets.sym	2003-01-15 01:03:27.000000000 +0100
@@ -1,4 +1,9 @@
 #include <sysdep.h>
 #include <tls.h>
 
+// This comment ensures USE_TLS is output inside of the test function
+#ifdef USE_TLS
 MULTIPLE_THREADS_OFFSET offsetof (struct _pthread_descr_struct, p_header.data.multiple_threads) - sizeof (struct _pthread_descr_struct)
+#else
+MULTIPLE_THREADS_OFFSET offsetof (tcbhead_t, multiple_threads)
+#endif
--- libc/scripts/gen-as-const.awk.jj	2002-12-28 00:05:53.000000000 +0100
+++ libc/scripts/gen-as-const.awk	2003-01-15 01:02:38.000000000 +0100
@@ -17,6 +17,9 @@ NF >= 1 && !started {
   started = 1;
 }
 
+# // comments go straight through, after starting the function
+/^\/\// { print; next }
+
 NF == 1 { sub(/^.*$/, "& &"); }
 
 NF > 1 {


	Jakub