From: Richard Henderson <rth@gcc.gnu.org>
Date: Mon, 18 Oct 1999 16:38:40 +0000 (-0700)
Subject: * ggc-page.c (init_ggc): Work around SunOS unaligned mmap bug.
X-Git-Tag: prereleases/libstdc++-2.92~9973
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1b3e142338984166b58727c31d24617cfc0a07dc;p=thirdparty%2Fgcc.git

* ggc-page.c (init_ggc): Work around SunOS unaligned mmap bug.

From-SVN: r30070
---

diff --git a/gcc/ggc-page.c b/gcc/ggc-page.c
index ecd116db5e63..24a8e2de2ad9 100644
--- a/gcc/ggc-page.c
+++ b/gcc/ggc-page.c
@@ -797,6 +797,26 @@ init_ggc ()
 
   G.allocated_last_gc = GGC_MIN_LAST_ALLOCATED;
 
+#ifdef HAVE_MMAP
+  /* StunOS has an amazing off-by-one error for the first mmap allocation
+     after fiddling with RLIMIT_STACK.  The result, as hard as it is to
+     believe, is an unaligned page allocation, which would cause us to
+     hork badly if we tried to use it.  */
+  {
+    char *p = alloc_anon (NULL, G.pagesize);
+    if ((size_t)p & (G.pagesize - 1))
+      {
+	/* How losing.  Discard this one and try another.  If we still
+	   can't get something useful, give up.  */
+
+	p = alloc_anon (NULL, G.pagesize);
+	if ((size_t)p & (G.pagesize - 1))
+	  abort ();
+      }
+    munmap (p, G.pagesize);
+  }
+#endif
+
   empty_string = ggc_alloc_string ("", 0);
   ggc_add_string_root (&empty_string, 1);
 }