Makefile.in (CRTSTUFF_CFLAGS): Add -fno-zero-initialized-in-bss.

	* Makefile.in (CRTSTUFF_CFLAGS): Add -fno-zero-initialized-in-bss.
	* doc/invoke.texi (-fno-zero-initialized-in-bss): Document.
	* flags.h (flag_zero_initialized_in_bss): Declare.
	* toplev.c (flag_zero_initialized_in_bss): New flag.
	(lang_independent_options): Add flag_zero_initialized_in_bss.
	* tree.c (initializer_zerop): New function.
	* tree.h (initializer_zerop): Declare.
	* varasm.c (assemble_variable): If we can emit bss, put zero
	initializers in the bss section.

From-SVN: r50218

1 files changed, 42 insertions, 0 deletions

diff --git a/gcc/tree.c b/gcc/tree.c
index 5e0210b..de65191 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -4975,3 +4975,45 @@ make_vector (mode, innertype, unsignedp)
 
   return t;
 }
+
+/* Given an initializer INIT, return TRUE if INIT is zero or some
+   aggregate of zeros.  Otherwise return FALSE.  */
+
+bool
+initializer_zerop (init)
+     tree init;
+{
+  STRIP_NOPS (init);
+
+  switch (TREE_CODE (init))
+    {
+    case INTEGER_CST:
+      return integer_zerop (init);
+    case REAL_CST:
+      return real_zerop (init)
+	&& ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (init));
+    case COMPLEX_CST:
+      return integer_zerop (init)
+	|| (real_zerop (init)
+	    && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (TREE_REALPART (init)))
+	    && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (TREE_IMAGPART (init))));
+    case CONSTRUCTOR:
+      {
+	if (AGGREGATE_TYPE_P (TREE_TYPE (init)))
+	{
+	  tree aggr_init = TREE_OPERAND (init, 1);
+	  
+	  while (aggr_init)
+	    {
+	      if (! initializer_zerop (TREE_VALUE (aggr_init)))
+		return false;
+	      aggr_init = TREE_CHAIN (aggr_init);
+	    }
+	  return true;
+	}
+	return false;
+      }
+    default:
+      return false;
+    }
+}