1 files changed, 284 insertions, 0 deletions
diff --git a/libmudflap/mf-hooks3.c b/libmudflap/mf-hooks3.c
new file mode 100644
index 000000000..79a5d5e8d
--- /dev/null
+++ b/libmudflap/mf-hooks3.c
@@ -0,0 +1,284 @@
+/* Mudflap: narrow-pointer bounds-checking by tree rewriting.
+   Copyright (C) 2002, 2003, 2004, 2005, 2009
+   Free Software Foundation, Inc.
+   Contributed by Frank Ch. Eigler <fche@redhat.com>
+   and Graydon Hoare <graydon@redhat.com>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+
+#include "config.h"
+
+#ifndef HAVE_SOCKLEN_T
+#define socklen_t int
+#endif
+
+/* These attempt to coax various unix flavours to declare all our
+   needed tidbits in the system headers.  */
+#if !defined(__FreeBSD__) && !defined(__APPLE__)
+#define _POSIX_SOURCE
+#endif /* Some BSDs break <sys/socket.h> if this is defined. */
+#define _GNU_SOURCE
+#define _XOPEN_SOURCE
+#define _BSD_TYPES
+#define __EXTENSIONS__
+#define _ALL_SOURCE
+#define _LARGE_FILE_API
+#define _XOPEN_SOURCE_EXTENDED 1
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <stdbool.h>
+
+#include "mf-runtime.h"
+#include "mf-impl.h"
+
+#ifdef _MUDFLAP
+#error "Do not compile this file with -fmudflap!"
+#endif
+
+#ifndef LIBMUDFLAPTH
+#error "pthreadstuff is to be included only in libmudflapth"
+#endif
+
+/* ??? Why isn't this done once in the header files.  */
+DECLARE(void *, malloc, size_t sz);
+DECLARE(void, free, void *ptr);
+DECLARE(int, pthread_create, pthread_t *thr, const pthread_attr_t *attr,
+	void * (*start) (void *), void *arg);
+
+
+/* Multithreading support hooks.  */
+
+
+#if !defined(HAVE_TLS) || defined(USE_EMUTLS)
+/* We don't have TLS.  Ordinarily we could use pthread keys, but since we're
+   commandeering malloc/free that presents a few problems.  The first is that
+   we'll recurse from __mf_get_state to pthread_setspecific to malloc back to
+   __mf_get_state during thread startup.  This can be solved with clever uses
+   of a mutex.  The second problem is that thread shutdown is indistinguishable
+   from thread startup, since libpthread is deallocating our state variable.
+   I've no good solution for this.
+
+   Which leaves us to handle this mess by totally by hand.  */
+
+/* Yes, we want this prime.  If pthread_t is a pointer, it's almost always
+   page aligned, and if we use a smaller power of 2, this results in "%N"
+   being the worst possible hash -- all threads hash to zero.  */
+#define LIBMUDFLAPTH_THREADS_MAX 1021
+
+struct mf_thread_data
+{
+  pthread_t self;
+  unsigned char used_p;
+  unsigned char state;
+};
+
+static struct mf_thread_data mf_thread_data[LIBMUDFLAPTH_THREADS_MAX];
+static pthread_mutex_t mf_thread_data_lock = PTHREAD_MUTEX_INITIALIZER;
+
+#define PTHREAD_HASH(p) ((unsigned long) (p) % LIBMUDFLAPTH_THREADS_MAX)
+
+static struct mf_thread_data *
+__mf_find_threadinfo (int alloc)
+{
+  pthread_t self = pthread_self ();
+  unsigned long hash = PTHREAD_HASH (self);
+  unsigned long rehash;
+
+#ifdef __alpha__
+  /* Alpha has the loosest memory ordering rules of all.  We need a memory
+     barrier to flush the reorder buffer before considering a *read* of a
+     shared variable.  Since we're not always taking a lock, we have to do
+     this by hand.  */
+  __sync_synchronize ();
+#endif
+
+  rehash = hash;
+  while (1)
+    {
+      if (mf_thread_data[rehash].used_p && mf_thread_data[rehash].self == self)
+	return &mf_thread_data[rehash];
+
+      rehash += 7;
+      if (rehash >= LIBMUDFLAPTH_THREADS_MAX)
+	rehash -= LIBMUDFLAPTH_THREADS_MAX;
+      if (rehash == hash)
+	break;
+    }
+
+  if (alloc)
+    {
+      pthread_mutex_lock (&mf_thread_data_lock);
+
+      rehash = hash;
+      while (1)
+	{
+	  if (!mf_thread_data[rehash].used_p)
+	    {
+	      mf_thread_data[rehash].self = self;
+	      __sync_synchronize ();
+	      mf_thread_data[rehash].used_p = 1;
+
+	      pthread_mutex_unlock (&mf_thread_data_lock);
+	      return &mf_thread_data[rehash];
+	    }
+
+	  rehash += 7;
+	  if (rehash >= LIBMUDFLAPTH_THREADS_MAX)
+	    rehash -= LIBMUDFLAPTH_THREADS_MAX;
+	  if (rehash == hash)
+	    break;
+	}
+
+      pthread_mutex_unlock (&mf_thread_data_lock);
+    }
+
+  return NULL;
+}
+
+enum __mf_state_enum
+__mf_get_state (void)
+{
+  struct mf_thread_data *data = __mf_find_threadinfo (0);
+  if (data)
+    return data->state;
+
+  /* If we've never seen this thread before, consider it to be in the
+     reentrant state.  The state gets reset to active for the main thread
+     in __mf_init, and for child threads in __mf_pthread_spawner.
+
+     The trickiest bit here is that the LinuxThreads pthread_manager thread
+     should *always* be considered to be reentrant, so that none of our 
+     hooks actually do anything.  Why?  Because that thread isn't a real
+     thread from the point of view of the thread library, and so lots of
+     stuff isn't initialized, leading to SEGV very quickly.  Even calling
+     pthread_self is a bit suspect, but it happens to work.  */
+
+  return reentrant;
+}
+
+void
+__mf_set_state (enum __mf_state_enum new_state)
+{
+  struct mf_thread_data *data = __mf_find_threadinfo (1);
+  data->state = new_state;
+}
+#endif
+
+/* The following two functions are used only with __mf_opts.heur_std_data.
+   We're interested in recording the location of the thread-local errno
+   variable.
+
+   Note that this doesn't handle TLS references in general; we have no
+   visibility into __tls_get_data for when that memory is allocated at
+   runtime.  Hopefully we get to see the malloc or mmap operation that
+   eventually allocates the backing store.  */
+
+/* Describe the startup information for a new user thread.  */
+struct mf_thread_start_info
+{
+  /* The user's thread entry point and argument.  */
+  void * (*user_fn)(void *);
+  void *user_arg;
+};
+
+
+static void
+__mf_pthread_cleanup (void *arg)
+{
+  if (__mf_opts.heur_std_data)
+    __mf_unregister (&errno, sizeof (errno), __MF_TYPE_GUESS);
+
+#if !defined(HAVE_TLS) || defined(USE_EMUTLS)
+  struct mf_thread_data *data = __mf_find_threadinfo (0);
+  if (data)
+    data->used_p = 0;
+#endif
+}
+
+
+static void *
+__mf_pthread_spawner (void *arg)
+{
+  void *result = NULL;
+
+  __mf_set_state (active);
+
+  /* NB: We could use __MF_TYPE_STATIC here, but we guess that the thread
+     errno is coming out of some dynamically allocated pool that we already
+     know of as __MF_TYPE_HEAP. */
+  if (__mf_opts.heur_std_data)
+    __mf_register (&errno, sizeof (errno), __MF_TYPE_GUESS,
+		   "errno area (thread)");
+
+  /* We considered using pthread_key_t objects instead of these
+     cleanup stacks, but they were less cooperative with the
+     interposed malloc hooks in libmudflap.  */
+  /* ??? The pthread_key_t problem is solved above...  */
+  pthread_cleanup_push (__mf_pthread_cleanup, NULL);
+
+  /* Extract given entry point and argument.  */
+  struct mf_thread_start_info *psi = arg;
+  void * (*user_fn)(void *) = psi->user_fn;
+  void *user_arg = psi->user_arg;
+  CALL_REAL (free, arg);
+
+  result = (*user_fn)(user_arg);
+
+  pthread_cleanup_pop (1 /* execute */);
+
+  return result;
+}
+
+
+#if PIC
+/* A special bootstrap variant. */
+int
+__mf_0fn_pthread_create (pthread_t *thr, const pthread_attr_t *attr,
+			 void * (*start) (void *), void *arg)
+{
+  return -1;
+}
+#endif
+
+
+#undef pthread_create
+WRAPPER(int, pthread_create, pthread_t *thr, const pthread_attr_t *attr,
+	 void * (*start) (void *), void *arg)
+{
+  struct mf_thread_start_info *si;
+
+  TRACE ("pthread_create\n");
+
+  /* Fill in startup-control fields.  */
+  si = CALL_REAL (malloc, sizeof (*si));
+  si->user_fn = start;
+  si->user_arg = arg;
+
+  /* Actually create the thread.  */
+  return CALL_REAL (pthread_create, thr, attr, __mf_pthread_spawner, si);
+}