libgo: Merge from revision 18783:00cce3a34d7e of master library.

This revision was committed January 7, 2014.  The next
revision deleted runtime/mfinal.c.  That will be done in a
subsequent merge.

This merge changes type descriptors to add a zero field,
pointing to a zero value for that type.  This is implemented
as a common variable.

	* go-gcc.cc (Gcc_backend::implicit_variable): Add is_common and
	alignment parameters.  Permit init parameter to be NULL.

From-SVN: r211249

1 files changed, 23 insertions, 4 deletions

diff --git a/gcc/go/go-gcc.cc b/gcc/go/go-gcc.cc
index 5b95e5d..df4b670 100644
--- a/gcc/go/go-gcc.cc
+++ b/gcc/go/go-gcc.cc
@@ -389,7 +389,8 @@ class Gcc_backend : public Backend
 		     Location, Bstatement**);
 
   Bvariable*
-  implicit_variable(const std::string&, Btype*, Bexpression*, bool);
+  implicit_variable(const std::string&, Btype*, Bexpression*, bool, bool,
+		    size_t);
 
   Bvariable*
   immutable_struct(const std::string&, bool, bool, Btype*, Location);
@@ -2497,10 +2498,15 @@ Gcc_backend::temporary_variable(Bfunction* function, Bblock* bblock,
 
 Bvariable*
 Gcc_backend::implicit_variable(const std::string& name, Btype* type,
-			       Bexpression* init, bool is_constant)
+			       Bexpression* init, bool is_constant,
+			       bool is_common, size_t alignment)
 {
   tree type_tree = type->get_tree();
-  tree init_tree = init->get_tree();
+  tree init_tree;
+  if (init == NULL)
+    init_tree = NULL_TREE;
+  else
+    init_tree = init->get_tree();
   if (type_tree == error_mark_node || init_tree == error_mark_node)
     return this->error_variable();
 
@@ -2510,12 +2516,25 @@ Gcc_backend::implicit_variable(const std::string& name, Btype* type,
   TREE_PUBLIC(decl) = 0;
   TREE_STATIC(decl) = 1;
   DECL_ARTIFICIAL(decl) = 1;
-  if (is_constant)
+  if (is_common)
+    {
+      DECL_COMMON(decl) = 1;
+      TREE_PUBLIC(decl) = 1;
+      gcc_assert(init_tree == NULL_TREE);
+    }
+  else if (is_constant)
     {
       TREE_READONLY(decl) = 1;
       TREE_CONSTANT(decl) = 1;
     }
   DECL_INITIAL(decl) = init_tree;
+
+  if (alignment != 0)
+    {
+      DECL_ALIGN(decl) = alignment * BITS_PER_UNIT;
+      DECL_USER_ALIGN(decl) = 1;
+    }
+
   rest_of_decl_compilation(decl, 1, 0);
 
   return new Bvariable(decl);