commit 5876f5032f60c45c4bd19e7ea7d0c14d0346b93e

Author: Jan Kratochvil <jan.kratochvil@redhat.com>

Date:   Wed May 21 16:25:53 2014 +0200

    Fix TLS access for -static -pthread

    I have posted:

    	TLS variables access for -static -lpthread executables

    	https://sourceware.org/ml/libc-help/2014-03/msg00024.html

    and the GDB patch below has been confirmed as OK for current glibcs.

    Further work should be done for newer glibcs:

    	Improve TLS variables glibc compatibility

    	https://sourceware.org/bugzilla/show_bug.cgi?id=16954

    Still the patch below implements the feature in a fully functional way backward

    compatible with current glibcs, it depends on the following glibc source line:

    	csu/libc-tls.c

    	main_map->l_tls_modid = 1;

    gdb/

    2014-05-21  Jan Kratochvil  <jan.kratochvil@redhat.com>

    	Fix TLS access for -static -pthread.

    	* linux-thread-db.c (struct thread_db_info): Add td_thr_tlsbase_p.

    	(try_thread_db_load_1): Initialize it.

    	(thread_db_get_thread_local_address): Call it if LM is zero.

    	* target.c (target_translate_tls_address): Remove LM_ADDR zero check.

    	* target.h (struct target_ops) (to_get_thread_local_address): Add

    	load_module_addr comment.

    gdb/gdbserver/

    2014-05-21  Jan Kratochvil  <jan.kratochvil@redhat.com>

    	Fix TLS access for -static -pthread.

    	* gdbserver/thread-db.c (struct thread_db): Add td_thr_tlsbase_p.

    	(thread_db_get_tls_address): Call it if LOAD_MODULE is zero.

    	(thread_db_load_search, try_thread_db_load_1): Initialize it.

    gdb/testsuite/

    2014-05-21  Jan Kratochvil  <jan.kratochvil@redhat.com>

    	Fix TLS access for -static -pthread.

    	* gdb.threads/staticthreads.c <HAVE_TLS> (tlsvar): New.

    	<HAVE_TLS> (thread_function, main): Initialize it.

    	* gdb.threads/staticthreads.exp: Try gdb_compile_pthreads for $have_tls.

    	Add clean_restart.

    	<$have_tls != "">: Check TLSVAR.

    Message-ID: <20140410115204.GB16411@host2.jankratochvil.net>

Index: gdb-7.6.1/gdb/gdbserver/thread-db.c

===================================================================

--- gdb-7.6.1.orig/gdb/gdbserver/thread-db.c

+++ gdb-7.6.1/gdb/gdbserver/thread-db.c

@@ -88,6 +88,9 @@ struct thread_db

   td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th,

 				     psaddr_t map_address,

 				     size_t offset, psaddr_t *address);

+  td_err_e (*td_thr_tlsbase_p) (const td_thrhandle_t *th,

+				unsigned long int modid,

+				psaddr_t *base);

   const char ** (*td_symbol_list_p) (void);

 };

@@ -497,7 +500,10 @@ thread_db_get_tls_address (struct thread

   if (thread_db == NULL || !thread_db->all_symbols_looked_up)

     return TD_ERR;

-  if (thread_db->td_thr_tls_get_addr_p == NULL)

+  /* If td_thr_tls_get_addr is missing rather do not expect td_thr_tlsbase

+     could work.  */

+  if (thread_db->td_thr_tls_get_addr_p == NULL

+      || (load_module == 0 && thread_db->td_thr_tlsbase_p == NULL))

     return -1;

   lwp = get_thread_lwp (thread);

@@ -508,12 +514,28 @@ thread_db_get_tls_address (struct thread

   saved_inferior = current_inferior;

   current_inferior = thread;

-  /* Note the cast through uintptr_t: this interface only works if

-     a target address fits in a psaddr_t, which is a host pointer.

-     So a 32-bit debugger can not access 64-bit TLS through this.  */

-  err = thread_db->td_thr_tls_get_addr_p (&lwp->th,

-					  (psaddr_t) (uintptr_t) load_module,

-					  offset, &addr);

+

+  if (load_module != 0)

+    {

+      /* Note the cast through uintptr_t: this interface only works if

+	 a target address fits in a psaddr_t, which is a host pointer.

+	 So a 32-bit debugger can not access 64-bit TLS through this.  */

+      err = thread_db->td_thr_tls_get_addr_p (&lwp->th,

+					     (psaddr_t) (uintptr_t) load_module,

+					      offset, &addr);

+    }

+  else

+    {

+      /* This code path handles the case of -static -pthread executables:

+	 https://sourceware.org/ml/libc-help/2014-03/msg00024.html

+	 For older GNU libc r_debug.r_map is NULL.  For GNU libc after

+	 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.

+	 The constant number 1 depends on GNU __libc_setup_tls

+	 initialization of l_tls_modid to 1.  */

+      err = thread_db->td_thr_tlsbase_p (&lwp->th, 1, &addr);

+      addr = (char *) addr + offset;

+    }

+

   current_inferior = saved_inferior;

   if (err == TD_OK)

     {

@@ -565,6 +587,7 @@ thread_db_load_search (void)

   tdb->td_ta_set_event_p = &td_ta_set_event;

   tdb->td_ta_event_getmsg_p = &td_ta_event_getmsg;

   tdb->td_thr_tls_get_addr_p = &td_thr_tls_get_addr;

+  tdb->td_thr_tlsbase_p = &td_thr_tlsbase;

   return 1;

 }

@@ -633,6 +656,7 @@ try_thread_db_load_1 (void *handle)

   CHK (0, tdb->td_ta_set_event_p = dlsym (handle, "td_ta_set_event"));

   CHK (0, tdb->td_ta_event_getmsg_p = dlsym (handle, "td_ta_event_getmsg"));

   CHK (0, tdb->td_thr_tls_get_addr_p = dlsym (handle, "td_thr_tls_get_addr"));

+  CHK (0, tdb->td_thr_tlsbase_p = dlsym (handle, "td_thr_tlsbase"));

 #undef CHK

Index: gdb-7.6.1/gdb/linux-thread-db.c

===================================================================

--- gdb-7.6.1.orig/gdb/linux-thread-db.c

+++ gdb-7.6.1/gdb/linux-thread-db.c

@@ -196,6 +196,9 @@ struct thread_db_info

   td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th,

 				     psaddr_t map_address,

 				     size_t offset, psaddr_t *address);

+  td_err_e (*td_thr_tlsbase_p) (const td_thrhandle_t *th,

+				unsigned long int modid,

+				psaddr_t *base);

 };

 /* List of known processes using thread_db, and the required

@@ -797,6 +800,7 @@ try_thread_db_load_1 (struct thread_db_i

   info->td_ta_event_getmsg_p = dlsym (info->handle, "td_ta_event_getmsg");

   info->td_thr_event_enable_p = dlsym (info->handle, "td_thr_event_enable");

   info->td_thr_tls_get_addr_p = dlsym (info->handle, "td_thr_tls_get_addr");

+  info->td_thr_tlsbase_p = dlsym (info->handle, "td_thr_tlsbase");

   if (thread_db_find_new_threads_silently (inferior_ptid) != 0)

     {

@@ -1798,21 +1802,39 @@ thread_db_get_thread_local_address (stru

       info = get_thread_db_info (GET_PID (ptid));

-      /* glibc doesn't provide the needed interface.  */

-      if (!info->td_thr_tls_get_addr_p)

-	throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR,

-		     _("No TLS library support"));

-

-      /* Caller should have verified that lm != 0.  */

-      gdb_assert (lm != 0);

-

       /* Finally, get the address of the variable.  */

-      /* Note the cast through uintptr_t: this interface only works if

-	 a target address fits in a psaddr_t, which is a host pointer.

-	 So a 32-bit debugger can not access 64-bit TLS through this.  */

-      err = info->td_thr_tls_get_addr_p (&thread_info->private->th,

-					 (psaddr_t)(uintptr_t) lm,

-					 offset, &address);

+      if (lm != 0)

+	{

+	  /* glibc doesn't provide the needed interface.  */

+	  if (!info->td_thr_tls_get_addr_p)

+	    throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR,

+			 _("No TLS library support"));

+

+	  /* Note the cast through uintptr_t: this interface only works if

+	     a target address fits in a psaddr_t, which is a host pointer.

+	     So a 32-bit debugger can not access 64-bit TLS through this.  */

+	  err = info->td_thr_tls_get_addr_p (&thread_info->private->th,

+					     (psaddr_t)(uintptr_t) lm,

+					     offset, &address);

+	}

+      else

+	{

+	  /* If glibc doesn't provide the needed interface throw an error

+	     that LM is zero - normally cases it should not be.  */

+	  if (!info->td_thr_tlsbase_p)

+	    throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR,

+			 _("TLS load module not found"));

+

+	  /* This code path handles the case of -static -pthread executables:

+	     https://sourceware.org/ml/libc-help/2014-03/msg00024.html

+	     For older GNU libc r_debug.r_map is NULL.  For GNU libc after

+	     PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.

+	     The constant number 1 depends on GNU __libc_setup_tls

+	     initialization of l_tls_modid to 1.  */

+	  err = info->td_thr_tlsbase_p (&thread_info->private->th,

+					1, &address);

+	  address = (char *) address + offset;

+	}

 #ifdef THREAD_DB_HAS_TD_NOTALLOC

       /* The memory hasn't been allocated, yet.  */

Index: gdb-7.6.1/gdb/target.c

===================================================================

--- gdb-7.6.1.orig/gdb/target.c

+++ gdb-7.6.1/gdb/target.c

@@ -1165,10 +1165,6 @@ target_translate_tls_address (struct obj

 	  /* Fetch the load module address for this objfile.  */

 	  lm_addr = gdbarch_fetch_tls_load_module_address (target_gdbarch (),

 	                                                   objfile);

-	  /* If it's 0, throw the appropriate exception.  */

-	  if (lm_addr == 0)

-	    throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR,

-			 _("TLS load module not found"));

 	  addr = target->to_get_thread_local_address (target, ptid,

 						      lm_addr, offset);

Index: gdb-7.6.1/gdb/target.h

===================================================================

--- gdb-7.6.1.orig/gdb/target.h

+++ gdb-7.6.1/gdb/target.h

@@ -557,7 +557,8 @@ struct target_ops

        thread-local storage for the thread PTID and the shared library

        or executable file given by OBJFILE.  If that block of

        thread-local storage hasn't been allocated yet, this function

-       may return an error.  */

+       may return an error.  LOAD_MODULE_ADDR may be zero for statically

+       linked multithreaded inferiors.  */

     CORE_ADDR (*to_get_thread_local_address) (struct target_ops *ops,

 					      ptid_t ptid,

 					      CORE_ADDR load_module_addr,

Index: gdb-7.6.1/gdb/testsuite/gdb.threads/staticthreads.c

===================================================================

--- gdb-7.6.1.orig/gdb/testsuite/gdb.threads/staticthreads.c

+++ gdb-7.6.1/gdb/testsuite/gdb.threads/staticthreads.c

@@ -28,10 +28,17 @@

 sem_t semaphore;

+#ifdef HAVE_TLS

+__thread int tlsvar;

+#endif

+

 void *

 thread_function (void *arg)

 {

-  printf ("Thread executing\n");

+#ifdef HAVE_TLS

+  tlsvar = 2;

+#endif

+  printf ("Thread executing\n"); /* tlsvar-is-set */

   while (sem_wait (&semaphore) != 0)

     {

       if (errno != EINTR)

@@ -57,6 +64,9 @@ main (int argc, char **argv)

       return -1;

     }

+#ifdef HAVE_TLS

+  tlsvar = 1;

+#endif

   /* Create a thread, wait for it to complete.  */

   {

Index: gdb-7.6.1/gdb/testsuite/gdb.threads/staticthreads.exp

===================================================================

--- gdb-7.6.1.orig/gdb/testsuite/gdb.threads/staticthreads.exp

+++ gdb-7.6.1/gdb/testsuite/gdb.threads/staticthreads.exp

@@ -22,11 +22,16 @@

 standard_testfile

 set static_flag "-static"

-if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" \

-	 executable \

-	 [list debug "additional_flags=${static_flag}" \

-	     ]] != "" } {

-    return -1

+foreach have_tls { "-DHAVE_TLS" "" } {

+    if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" \

+	     executable \

+	     [list debug "additional_flags=${static_flag} ${have_tls}" \

+		 ]] == "" } {

+	break

+    }

+    if { $have_tls == "" } {

+	return -1

+    }

 }

 clean_restart ${binfile}

@@ -96,3 +101,18 @@ gdb_test_multiple "quit" "$test" {

         pass "$test"

     }

 }

+clean_restart ${binfile}

+

+

+if { "$have_tls" != "" } {

+    if ![runto_main] {

+	return -1

+    }

+    gdb_breakpoint [gdb_get_line_number "tlsvar-is-set"]

+    gdb_continue_to_breakpoint "tlsvar-is-set" ".* tlsvar-is-set .*"

+    gdb_test "p tlsvar" " = 2" "tlsvar in thread"

+    gdb_test "thread 1" ".*"

+    # Unwind from pthread_join.

+    gdb_test "up 10" " in main .*"

+    gdb_test "p tlsvar" " = 1" "tlsvar in main"

+}