add the source code for GNU lightning in the source directory for the C runtime

1 files changed, 91 insertions, 0 deletions

diff --git a/src/runtime/c/pgf/lightning/i386/funcs.h b/src/runtime/c/pgf/lightning/i386/funcs.h
new file mode 100644
index 000000000..1e247049f
--- /dev/null
+++ b/src/runtime/c/pgf/lightning/i386/funcs.h
@@ -0,0 +1,91 @@
+/******************************** -*- C -*- ****************************
+ *
+ *	Platform-independent layer inline functions (i386)
+ *
+ ***********************************************************************/
+
+
+/***********************************************************************
+ *
+ * Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
+ * Written by Paolo Bonzini.
+ *
+ * This file is part of GNU lightning.
+ *
+ * GNU lightning is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; either version 2.1, or (at your option)
+ * any later version.
+ * 
+ * GNU lightning 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 Lesser General Public
+ * License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with GNU lightning; see the file COPYING.LESSER; if not, write to the
+ * Free Software Foundation, 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ *
+ ***********************************************************************/
+
+
+
+#ifndef __lightning_funcs_h
+#define __lightning_funcs_h
+
+#ifdef __linux__
+#include <unistd.h>
+#include <sys/mman.h>
+#endif
+
+static void
+jit_flush_code(void *dest, void *end)
+{
+  /* On the x86, the PROT_EXEC bits are not handled by the MMU.
+     However, the kernel can emulate this by setting the code
+     segment's limit to the end address of the highest page
+     whose PROT_EXEC bit is set.
+
+     Linux kernels that do so and that disable by default the
+     execution of the data and stack segment are becoming more
+     and more common (Fedora, for example), so we implement our
+     jit_flush_code as an mprotect.  */
+#ifdef __linux__
+  static unsigned long prev_page = 0, prev_length = 0;
+  int page, length;
+#ifdef PAGESIZE
+  const int page_size = PAGESIZE;
+#else
+  static int page_size = -1;
+  if (page_size == -1)
+    page_size = sysconf (_SC_PAGESIZE);
+#endif
+
+  page = (long) dest & ~(page_size - 1);
+  length = ((char *) end - (char *) page + page_size - 1) & ~(page_size - 1);
+
+  /* Simple-minded attempt at optimizing the common case where a single
+     chunk of memory is used to compile multiple functions.  */
+  if (page >= prev_page && page + length <= prev_page + prev_length)
+    return;
+
+  mprotect ((void *) page, length, PROT_READ | PROT_WRITE | PROT_EXEC);
+
+  /* See if we can extend the previously mprotect'ed memory area towards
+     higher addresses: the starting address remains the same as before.  */
+  if (page >= prev_page && page <= prev_page + prev_length)
+    prev_length = page + length - prev_page;
+
+  /* See if we can extend the previously mprotect'ed memory area towards
+     lower addresses: the highest address remains the same as before.  */
+  else if (page < prev_page && page + length <= prev_page + prev_length)
+    prev_length += prev_page - page, prev_page = page;
+
+  /* Nothing to do, replace the area.  */
+  else
+    prev_page = page, prev_length = length;
+#endif
+}
+
+#endif /* __lightning_funcs_h */