Re: [CHKP] Support returned bounds in thunks expand

[Ilya Enkovich <enkovich.gnu@gmail.com>]

> > 
> > The problem with instrumented call is that instrumented function
> > returns two values and call lhs gets only the first one. Thus we
> > generate bndret call to get the second one to build own return with
> > two values.
> 
> I see, patch is OK then (preferably merging as much as possible with ipa-split)
> 
> Honza

Here is a refactored version with common code moved to tree-chkp.c.  Bootstrapped and tested on x86_64-unknown-linux-gnu.  Does it look OK?

Thanks,
Ilya
--
gcc/

2015-04-07  Ilya Enkovich  <ilya.enkovich@intel.com>

	* tree-chkp.h (chkp_insert_retbnd_call): New.
	* tree-chkp.c (chkp_insert_retbnd_call): New.
	* ipa-split.c (insert_bndret_call_after): Remove.
	(split_function): Use chkp_insert_retbnd_call.
	* cgraphunit.c (cgraph_node::expand_thunk): Build returned
	bounds for instrumented functions.

gcc/testsuite/

2015-04-07  Ilya Enkovich  <ilya.enkovich@intel.com>

	* gcc/testsuite/gcc.target/i386/thunk-retbnd.c: New.


diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index 8ac92e1..ca34c31 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -1581,6 +1581,7 @@ cgraph_node::expand_thunk (bool output_asm_thunks, bool force_gimple_thunk)
       int i;
       tree resdecl;
       tree restmp = NULL;
+      tree resbnd = NULL;
 
       gcall *call;
       greturn *ret;
@@ -1697,6 +1698,17 @@ cgraph_node::expand_thunk (bool output_asm_thunks, bool force_gimple_thunk)
       gsi_insert_after (&bsi, call, GSI_NEW_STMT);
       if (!alias_is_noreturn)
 	{
+	  if (instrumentation_clone
+	      && !DECL_BY_REFERENCE (resdecl)
+	      && restmp
+	      && BOUNDED_P (restmp))
+	    {
+	      resbnd = chkp_insert_retbnd_call (NULL, restmp, &bsi);
+	      create_edge (get_create (gimple_call_fndecl (gsi_stmt (bsi))),
+			   as_a <gcall *> (gsi_stmt (bsi)),
+			   callees->count, callees->frequency);
+	    }
+
 	  if (restmp && !this_adjusting
 	      && (fixed_offset || virtual_offset))
 	    {
@@ -1766,6 +1778,7 @@ cgraph_node::expand_thunk (bool output_asm_thunks, bool force_gimple_thunk)
 	    ret = gimple_build_return (restmp);
 	  else
 	    ret = gimple_build_return (resdecl);
+	  gimple_return_set_retbnd (ret, resbnd);
 
 	  gsi_insert_after (&bsi, ret, GSI_NEW_STMT);
 	}
diff --git a/gcc/ipa-split.c b/gcc/ipa-split.c
index 5d5db0e..f4bd8d7 100644
--- a/gcc/ipa-split.c
+++ b/gcc/ipa-split.c
@@ -1230,20 +1230,6 @@ find_split_points (basic_block return_bb, int overall_time, int overall_size)
   BITMAP_FREE (current.ssa_names_to_pass);
 }
 
-/* Build and insert initialization of returned bounds RETBND
-   for returned value RETVAL.  Statements are inserted after
-   a statement pointed by GSI and GSI is modified to point to
-   the last inserted statement.  */
-
-static void
-insert_bndret_call_after (tree retbnd, tree retval, gimple_stmt_iterator *gsi)
-{
-  tree fndecl = targetm.builtin_chkp_function (BUILT_IN_CHKP_BNDRET);
-  gimple bndret = gimple_build_call (fndecl, 1, retval);
-  gimple_call_set_lhs (bndret, retbnd);
-  gsi_insert_after (gsi, bndret, GSI_CONTINUE_LINKING);
-}
-
 /* Split function at SPLIT_POINT.  */
 
 static void
@@ -1650,7 +1636,7 @@ split_function (basic_block return_bb, struct split_point *split_point,
 		    }
 		  /* Build bndret call to obtain returned bounds.  */
 		  if (retbnd)
-		    insert_bndret_call_after (retbnd, retval, &gsi);
+		    chkp_insert_retbnd_call (retbnd, retval, &gsi);
 		  gimple_call_set_lhs (call, retval);
 		  update_stmt (call);
 		}
@@ -1700,7 +1686,7 @@ split_function (basic_block return_bb, struct split_point *split_point,
           gsi_insert_after (&gsi, call, GSI_NEW_STMT);
 	  /* Build bndret call to obtain returned bounds.  */
 	  if (retbnd)
-	    insert_bndret_call_after (retbnd, retval, &gsi);
+	    chkp_insert_retbnd_call (retbnd, retval, &gsi);
 	  if (tsan_func_exit_call)
 	    gsi_insert_after (&gsi, tsan_func_exit_call, GSI_NEW_STMT);
 	  ret = gimple_build_return (retval);
diff --git a/gcc/testsuite/gcc.target/i386/thunk-retbnd.c b/gcc/testsuite/gcc.target/i386/thunk-retbnd.c
new file mode 100644
index 0000000..d9bd031
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/thunk-retbnd.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target mpx } */
+/* { dg-options "-O2 -fcheck-pointer-bounds -mmpx -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-times "return &glob," 2 "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */
+
+int glob;
+
+int *
+test1 (void)
+{
+  return &glob;
+}
+
+int *
+test2 (void)
+{
+  return test1 ();
+}
diff --git a/gcc/tree-chkp.c b/gcc/tree-chkp.c
index 03f75b3..541af29 100644
--- a/gcc/tree-chkp.c
+++ b/gcc/tree-chkp.c
@@ -500,6 +500,35 @@ chkp_expand_bounds_reset_for_mem (tree mem, tree ptr)
   expand_normal (bndstx);
 }
 
+/* Build retbnd call for returned value RETVAL.
+
+   If BNDVAL is not NULL then result is stored
+   in it.  Otherwise a temporary is created to
+   hold returned value.
+
+   GSI points to a position for a retbnd call
+   and is set to created stmt.
+
+   Cgraph edge is created for a new call if
+   UPDATE_EDGE is 1.
+
+   Obtained bounds are returned.  */
+tree
+chkp_insert_retbnd_call (tree bndval, tree retval,
+			 gimple_stmt_iterator *gsi)
+{
+  gimple call;
+
+  if (!bndval)
+    bndval = create_tmp_reg (pointer_bounds_type_node, "retbnd");
+
+  call = gimple_build_call (chkp_ret_bnd_fndecl, 1, retval);
+  gimple_call_set_lhs (call, bndval);
+  gsi_insert_after (gsi, call, GSI_CONTINUE_LINKING);
+
+  return bndval;
+}
+
 /* Mark statement S to not be instrumented.  */
 static void
 chkp_mark_stmt (gimple s)
diff --git a/gcc/tree-chkp.h b/gcc/tree-chkp.h
index 86f3618..1bafe99 100644
--- a/gcc/tree-chkp.h
+++ b/gcc/tree-chkp.h
@@ -54,5 +54,7 @@ extern void chkp_copy_bounds_for_assign (gimple assign,
 extern bool chkp_gimple_call_builtin_p (gimple call,
 					enum built_in_function code);
 extern void chkp_expand_bounds_reset_for_mem (tree mem, tree ptr);
+extern tree chkp_insert_retbnd_call (tree bndval, tree retval,
+				     gimple_stmt_iterator *gsi);
 
 #endif /* GCC_TREE_CHKP_H */