[PATCH, PR63995, CHKP] Use single static bounds var for varpool nodes sharing asm name

[Ilya Enkovich]

Hi,

This patch partly fixes PR bootstrap/63995 by avoiding duplicating static 
bounds vars.  With this fix bootstrap still fails at stage 2 and 3 comparison.

Bootstrapped and checked on x86_64-unknown-linux-gnu.  OK for trunk?

Thanks,
Ilya
--
gcc/

2014-11-25  Ilya Enkovich  <ilya.enkov...@intel.com>

        PR bootstrap/63995
        * tree-chkp (chkp_make_static_bounds): Share bounds var
        between nodes sharing assembler name.

gcc/testsuite

2014-11-25  Ilya Enkovich  <ilya.enkov...@intel.com>

        PR bootstrap/63995
        * g++.dg/dg.exp: Add mpx-dg.exp.
        * g++.dg/pr63995-1.C: New.


diff --git a/gcc/testsuite/g++.dg/dg.exp b/gcc/testsuite/g++.dg/dg.exp
index 14beae1..44eab0c 100644
--- a/gcc/testsuite/g++.dg/dg.exp
+++ b/gcc/testsuite/g++.dg/dg.exp
@@ -18,6 +18,7 @@
 
 # Load support procs.
 load_lib g++-dg.exp
+load_lib mpx-dg.exp
 
 # If a testcase doesn't have special options, use these.
 global DEFAULT_CXXFLAGS
diff --git a/gcc/testsuite/g++.dg/pr63995-1.C b/gcc/testsuite/g++.dg/pr63995-1.C
new file mode 100644
index 0000000..82e7606
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr63995-1.C
@@ -0,0 +1,16 @@
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-require-effective-target mpx } */
+/* { dg-options "-O2 -g -fcheck-pointer-bounds -mmpx" } */
+
+int test1 (int i)
+{
+  extern const int arr[10];
+  return arr[i];
+}
+
+extern const int arr[10];
+
+int test2 (int i)
+{
+  return arr[i];
+}
diff --git a/gcc/tree-chkp.c b/gcc/tree-chkp.c
index 3e38691..d425084 100644
--- a/gcc/tree-chkp.c
+++ b/gcc/tree-chkp.c
@@ -2727,9 +2727,29 @@ chkp_make_static_bounds (tree obj)
   /* First check if we already have required var.  */
   if (chkp_static_var_bounds)
     {
-      slot = chkp_static_var_bounds->get (obj);
-      if (slot)
-       return *slot;
+      /* If there is a symbol sharing assembler name with obj,
+        we may use its bounds.  */
+      if (TREE_CODE (obj) == VAR_DECL)
+       {
+         varpool_node *node = varpool_node::get_create (obj);
+
+         while (node->previous_sharing_asm_name)
+           node = (varpool_node *)node->previous_sharing_asm_name;
+
+         while (node)
+           {
+             slot = chkp_static_var_bounds->get (node->decl);
+             if (slot)
+               return *slot;
+             node = (varpool_node *)node->next_sharing_asm_name;
+           }
+       }
+      else
+       {
+         slot = chkp_static_var_bounds->get (obj);
+         if (slot)
+           return *slot;
+       }
     }
 
   /* Build decl for bounds var.  */