compiler: add calling Bfunction Backend::call_expression

[gcc.git] / libitm / local.cc

diff --git a/libitm/local.cc b/libitm/local.cc
index fab73c508956a899a581f2b1c1664a5a3e497782..d87cd1505f7f635dec11cae72edf64ffac2db24a 100644 (file)
--- a/libitm/local.cc
+++ b/libitm/local.cc
@@ -1,4 +1,4 @@
-/* Copyright (C) 2008, 2009, 2011 Free Software Foundation, Inc.
+/* Copyright (C) 2008-2017 Free Software Foundation, Inc.
    Contributed by Richard Henderson <rth@redhat.com>.
 
    This file is part of the GNU Transactional Memory Library (libitm).
@@ -26,67 +26,42 @@
 
 namespace GTM HIDDEN {
 
-struct gtm_undolog_entry
-{
-  void *addr;
-  size_t len;
-  char saved[];
-};
-
-
-void
-gtm_thread::commit_undolog ()
-{
-  size_t i, n = undolog.size();
-
-  if (n > 0)
-    {
-      for (i = 0; i < n; ++i)
-       free (undolog[i]);
-      this->undolog.clear();
-    }
-}
-
-void
-gtm_thread::rollback_undolog (size_t until_size)
+// This function needs to be noinline because we need to prevent that it gets
+// inlined into another function that calls further functions. This could
+// break our assumption that we only call memcpy and thus only need to
+// additionally protect the memcpy stack (see the hack in mask_stack_bottom()).
+// Even if that isn't an issue because those other calls don't happen during
+// copying, we still need mask_stack_bottom() to be called "close" to the
+// memcpy in terms of stack frames, so just ensure that for now using the
+// noinline.
+void __attribute__((noinline))
+gtm_undolog::rollback (gtm_thread* tx, size_t until_size)
 {
   size_t i, n = undolog.size();
+  void *top = mask_stack_top(tx);
+  void *bot = mask_stack_bottom(tx);
 
   if (n > 0)
     {
       for (i = n; i-- > until_size; )
        {
-         gtm_undolog_entry *u = *undolog.pop();
-         if (u)
-           {
-             memcpy (u->addr, u->saved, u->len);
-             free (u);
-           }
-       }
-    }
-}
-
-/* Forget any references to PTR in the local log.  */
-
-void
-gtm_thread::drop_references_undolog (const void *ptr, size_t len)
-{
-  size_t i, n = undolog.size();
-
-  if (n > 0)
-    {
-      for (i = n; i > 0; i--)
-       {
-         gtm_undolog_entry *u = undolog[i];
-         /* ?? Do we need such granularity, or can we get away with
-            just comparing PTR and LEN. ??  */
-         if ((const char *)u->addr >= (const char *)ptr
-             && ((const char *)u->addr + u->len <= (const char *)ptr + len))
-           {
-             free (u);
-             undolog[i] = NULL;
-           }
+          void *ptr = (void *) undolog[i--];
+          size_t len = undolog[i];
+          size_t words = (len + sizeof(gtm_word) - 1) / sizeof(gtm_word);
+          i -= words;
+          // Filter out any updates that overlap the libitm stack.  We don't
+          // bother filtering out just the overlapping bytes because we don't
+          // merge writes and thus any overlapping write is either bogus or
+          // would restore data on stack frames that are not in use anymore.
+          // FIXME The memcpy can/will end up as another call but we
+          // calculated BOT based on the current function.  Can we inline or
+          // reimplement this without too much trouble due to unaligned calls
+          // and still have good performance, so that we can remove the hack
+          // in mask_stack_bottom()?
+          if (likely(ptr > top || (uint8_t*)ptr + len <= bot))
+            __builtin_memcpy (ptr, &undolog[i], len);
        }
+      undolog.set_size(until_size);
     }
 }
 
@@ -94,24 +69,21 @@ void ITM_REGPARM
 GTM_LB (const void *ptr, size_t len)
 {
   gtm_thread *tx = gtm_thr();
-  gtm_undolog_entry *undo;
-
-  undo = (gtm_undolog_entry *)
-      xmalloc (sizeof (struct gtm_undolog_entry) + len);
-  undo->addr = (void *) ptr;
-  undo->len = len;
-
-  tx->undolog.push()[0] = undo;
-
-  memcpy (undo->saved, ptr, len);
+  tx->undolog.log(ptr, len);
 }
 
 } // namespace GTM
 
 using namespace GTM;
 
-void _ITM_LB (const void *ptr, size_t len) ITM_REGPARM
-       __attribute__((alias("GTM_LB")));
+/* ??? Use configure to determine if aliases are supported.  Or convince
+   the compiler to not just tail call this, but actually generate the
+   same_body_alias itself.  */
+void ITM_REGPARM
+_ITM_LB (const void *ptr, size_t len)
+{
+  GTM_LB (ptr, len);
+}
 
 #define ITM_LOG_DEF(T) \
 void ITM_REGPARM _ITM_L##T (const _ITM_TYPE_##T *ptr) \