Use backend interface for zero initialization.

	* go-gcc.cc (Gcc_backend::zero_expression): New function.

From-SVN: r174863

gcc/go/ChangeLog

+2011-06-09  Ian Lance Taylor  <iant@google.com>
+
+	* go-gcc.cc (Gcc_backend::zero_expression): New function.
+
 2011-06-07  Richard Guenther  <rguenther@suse.de>
 
 	* go-lang.c (go_langhook_init): Do not set

gcc/go/go-gcc.cc

@@ -194,6 +194,11 @@ class Gcc_backend : public Backend
   bool
   is_circular_pointer_type(Btype*);
 
+  // Expressions.
+
+  Bexpression*
+  zero_expression(Btype*);
+
   // Statements.
 
   Bstatement*
@@ -700,6 +705,20 @@ Gcc_backend::is_circular_pointer_type(Btype* btype)
   return btype->get_tree() == ptr_type_node;
 }
 
+// Return the zero value for a type.
+
+Bexpression*
+Gcc_backend::zero_expression(Btype* btype)
+{
+  tree t = btype->get_tree();
+  tree ret;
+  if (t == error_mark_node)
+    ret = error_mark_node;
+  else
+    ret = build_zero_cst(t);
+  return tree_to_expr(ret);
+}
+
 // An expression as a statement.
 
 Bstatement*

gcc/go/gofrontend/backend.h

@@ -198,6 +198,14 @@ class Backend
   virtual bool
   is_circular_pointer_type(Btype*) = 0;
 
+  // Expressions.
+
+  // Return an expression for a zero value of the given type.  This is
+  // used for cases such as local variable initialization and
+  // converting nil to other types.
+  virtual Bexpression*
+  zero_expression(Btype*) = 0;
+
   // Statements.
 
   // Create an error statement.  This is used for cases which should

gcc/go/gofrontend/expressions.cc

@@ -318,7 +318,10 @@ Expression::convert_type_to_interface(Translate_context* context,
   // When setting an interface to nil, we just set both fields to
   // NULL.
   if (rhs_type->is_nil_type())
-    return lhs_type->get_init_tree(gogo, false);
+    {
+      Btype* lhs_btype = lhs_type->get_backend(gogo);
+      return expr_to_tree(gogo->backend()->zero_expression(lhs_btype));
+    }
 
   // This should have been checked already.
   go_assert(lhs_interface_type->implements_interface(rhs_type, NULL));
@@ -10046,12 +10049,14 @@ Map_index_expression::do_get_tree(Translate_context* context)
     }
   else
     {
+      Gogo* gogo = context->gogo();
+      Btype* val_btype = type->val_type()->get_backend(gogo);
+      Bexpression* val_zero = gogo->backend()->zero_expression(val_btype);
       return fold_build3(COND_EXPR, val_type_tree,
 			 fold_build2(EQ_EXPR, boolean_type_node, valptr,
 				     fold_convert(TREE_TYPE(valptr),
 						  null_pointer_node)),
-			 type->val_type()->get_init_tree(context->gogo(),
-							 false),
+			 expr_to_tree(val_zero),
 			 build_fold_indirect_ref(valptr));
     }
 }
@@ -10958,7 +10963,10 @@ Struct_construction_expression::do_get_tree(Translate_context* context)
   Gogo* gogo = context->gogo();
 
   if (this->vals_ == NULL)
-    return this->type_->get_init_tree(gogo, false);
+    {
+      Btype* btype = this->type_->get_backend(gogo);
+      return expr_to_tree(gogo->backend()->zero_expression(btype));
+    }
 
   tree type_tree = type_to_tree(this->type_->get_backend(gogo));
   if (type_tree == error_mark_node)
@@ -10977,12 +10985,14 @@ Struct_construction_expression::do_get_tree(Translate_context* context)
     {
       go_assert(pf != fields->end());
 
+      Btype* fbtype = pf->type()->get_backend(gogo);
+
       tree val;
       if (pv == this->vals_->end())
-	val = pf->type()->get_init_tree(gogo, false);
+	val = expr_to_tree(gogo->backend()->zero_expression(fbtype));
       else if (*pv == NULL)
 	{
-	  val = pf->type()->get_init_tree(gogo, false);
+	  val = expr_to_tree(gogo->backend()->zero_expression(fbtype));
 	  ++pv;
 	}
       else
@@ -11217,7 +11227,12 @@ Array_construction_expression::get_constructor_tree(Translate_context* context,
 	  constructor_elt* elt = VEC_quick_push(constructor_elt, values, NULL);
 	  elt->index = size_int(i);
 	  if (*pv == NULL)
-	    elt->value = element_type->get_init_tree(context->gogo(), false);
+	    {
+	      Gogo* gogo = context->gogo();
+	      Btype* ebtype = element_type->get_backend(gogo);
+	      Bexpression *zv = gogo->backend()->zero_expression(ebtype);
+	      elt->value = expr_to_tree(zv);
+	    }
 	  else
 	    {
 	      tree value_tree = (*pv)->get_tree(context);
@@ -11363,7 +11378,9 @@ Open_array_construction_expression::do_get_tree(Translate_context* context)
       VEC(constructor_elt,gc)* vec = VEC_alloc(constructor_elt, gc, 1);
       constructor_elt* elt = VEC_quick_push(constructor_elt, vec, NULL);
       elt->index = size_int(0);
-      elt->value = element_type->get_init_tree(context->gogo(), false);
+      Gogo* gogo = context->gogo();
+      Btype* btype = element_type->get_backend(gogo);
+      elt->value = expr_to_tree(gogo->backend()->zero_expression(btype));
       values = build_constructor(constructor_type, vec);
       if (TREE_CONSTANT(elt->value))
 	TREE_CONSTANT(values) = 1;

gcc/go/gofrontend/gogo-tree.cc

@@ -1035,9 +1035,10 @@ Variable::get_init_tree(Gogo* gogo, Named_object* function)
   if (this->init_ == NULL)
     {
       go_assert(!this->is_parameter_);
-      return this->type_->get_init_tree(gogo,
-					(this->is_global_
-					 || this->is_in_heap()));
+      if (this->is_global_ || this->is_in_heap())
+	return NULL;
+      Btype* btype = this->type_->get_backend(gogo);
+      return expr_to_tree(gogo->backend()->zero_expression(btype));
     }
   else
     {
@@ -1286,7 +1287,8 @@ Function::make_receiver_parm_decl(Gogo* gogo, Named_object* no, tree var_decl)
 						null_pointer_node));
   tree ind = build_fold_indirect_ref_loc(loc, parm_decl);
   TREE_THIS_NOTRAP(ind) = 1;
-  tree zero_init = no->var_value()->type()->get_init_tree(gogo, false);
+  Btype* btype = no->var_value()->type()->get_backend(gogo);
+  tree zero_init = expr_to_tree(gogo->backend()->zero_expression(btype));
   tree init = fold_build3_loc(loc, COND_EXPR, TREE_TYPE(ind),
 			      check, ind, zero_init);
 
@@ -1423,7 +1425,10 @@ Function::build_tree(Gogo* gogo, Named_object* named_function)
 	  Type* type = (*p)->result_var_value()->type();
 	  tree init;
 	  if (!(*p)->result_var_value()->is_in_heap())
-	    init = type->get_init_tree(gogo, false);
+	    {
+	      Btype* btype = type->get_backend(gogo);
+	      init = expr_to_tree(gogo->backend()->zero_expression(btype));
+	    }
 	  else
 	    {
 	      source_location loc = (*p)->location();
@@ -1432,20 +1437,7 @@ Function::build_tree(Gogo* gogo, Named_object* named_function)
 						 TYPE_SIZE_UNIT(type_tree),
 						 loc);
 	      tree ptr_type_tree = build_pointer_type(type_tree);
-	      tree subinit = type->get_init_tree(gogo, true);
-	      if (subinit == NULL_TREE)
-		init = fold_convert_loc(loc, ptr_type_tree, space);
-	      else
-		{
-		  space = save_expr(space);
-		  space = fold_convert_loc(loc, ptr_type_tree, space);
-		  tree spaceref = build_fold_indirect_ref_loc(loc, space);
-		  TREE_THIS_NOTRAP(spaceref) = 1;
-		  tree set = fold_build2_loc(loc, MODIFY_EXPR, void_type_node,
-					     spaceref, subinit);
-		  init = fold_build2_loc(loc, COMPOUND_EXPR, TREE_TYPE(space),
-					 set, space);
-		}
+	      init = fold_convert_loc(loc, ptr_type_tree, space);
 	    }
 
 	  if (var_decl != error_mark_node)

gcc/go/gofrontend/gogo.cc

@@ -1498,6 +1498,10 @@ Check_types_traverse::variable(Named_object* named_object)
   if (named_object->is_variable())
     {
       Variable* var = named_object->var_value();
+
+      // Give error if variable type is not defined.
+      var->type()->base();
+
       Expression* init = var->init();
       std::string reason;
       if (init != NULL

gcc/go/gofrontend/types.h

@@ -825,19 +825,6 @@ class Type
   Btype*
   get_backend(Gogo*);
 
-  // Return a tree representing a zero initialization for this type.
-  // This will be something like an INTEGER_CST or a CONSTRUCTOR.  If
-  // IS_CLEAR is true, then the memory is known to be zeroed; in that
-  // case, this will return NULL if there is nothing to be done.
-  tree
-  get_init_tree(Gogo*, bool is_clear);
-
-  // Like get_init_tree, but passing in the type to use for the
-  // initializer.
-  tree
-  get_typed_init_tree(Gogo* gogo, tree type_tree, bool is_clear)
-  { return this->do_get_init_tree(gogo, type_tree, is_clear); }
-
   // Return a tree for a make expression applied to this type.
   tree
   make_expression_tree(Translate_context* context, Expression_list* args,
@@ -896,9 +883,6 @@ class Type
   do_get_backend(Gogo*) = 0;
 
   virtual tree
-  do_get_init_tree(Gogo*, tree, bool) = 0;
-
-  virtual tree
   do_make_expression_tree(Translate_context*, Expression_list*,
 			  source_location);
 
@@ -1334,9 +1318,6 @@ class Integer_type : public Type
   Btype*
   do_get_backend(Gogo*);
 
-  tree
-  do_get_init_tree(Gogo*, tree, bool);
-
   Expression*
   do_type_descriptor(Gogo*, Named_type*);
 
@@ -1406,9 +1387,6 @@ class Float_type : public Type
   Btype*
   do_get_backend(Gogo*);
 
-  tree
-  do_get_init_tree(Gogo*, tree, bool);
-
   Expression*
   do_type_descriptor(Gogo*, Named_type*);
 
@@ -1474,9 +1452,6 @@ class Complex_type : public Type
   Btype*
   do_get_backend(Gogo*);
 
-  tree
-  do_get_init_tree(Gogo*, tree, bool);
-
   Expression*
   do_type_descriptor(Gogo*, Named_type*);
 
@@ -1530,9 +1505,6 @@ class String_type : public Type
   Btype*
   do_get_backend(Gogo*);
 
-  tree
-  do_get_init_tree(Gogo* gogo, tree, bool);
-
   Expression*
   do_type_descriptor(Gogo*, Named_type*);
 
@@ -1650,9 +1622,6 @@ class Function_type : public Type
   Btype*
   do_get_backend(Gogo*);
 
-  tree
-  do_get_init_tree(Gogo*, tree, bool);
-
   Expression*
   do_type_descriptor(Gogo*, Named_type*);
 
@@ -1734,9 +1703,6 @@ class Pointer_type : public Type
   Btype*
   do_get_backend(Gogo*);
 
-  tree
-  do_get_init_tree(Gogo*, tree, bool);
-
   Expression*
   do_type_descriptor(Gogo*, Named_type*);
 
@@ -1988,9 +1954,6 @@ class Struct_type : public Type
   Btype*
   do_get_backend(Gogo*);
 
-  tree
-  do_get_init_tree(Gogo*, tree, bool);
-
   Expression*
   do_type_descriptor(Gogo*, Named_type*);
 
@@ -2106,9 +2069,6 @@ class Array_type : public Type
   do_get_backend(Gogo*);
 
   tree
-  do_get_init_tree(Gogo*, tree, bool);
-
-  tree
   do_make_expression_tree(Translate_context*, Expression_list*,
 			  source_location);
 
@@ -2197,9 +2157,6 @@ class Map_type : public Type
   do_get_backend(Gogo*);
 
   tree
-  do_get_init_tree(Gogo*, tree, bool);
-
-  tree
   do_make_expression_tree(Translate_context*, Expression_list*,
 			  source_location);
 
@@ -2281,9 +2238,6 @@ class Channel_type : public Type
   do_get_backend(Gogo*);
 
   tree
-  do_get_init_tree(Gogo*, tree, bool);
-
-  tree
   do_make_expression_tree(Translate_context*, Expression_list*,
 			  source_location);
 
@@ -2398,9 +2352,6 @@ class Interface_type : public Type
   Btype*
   do_get_backend(Gogo*);
 
-  tree
-  do_get_init_tree(Gogo* gogo, tree, bool);
-
   Expression*
   do_type_descriptor(Gogo*, Named_type*);
 
@@ -2630,10 +2581,6 @@ class Named_type : public Type
   do_get_backend(Gogo*);
 
   tree
-  do_get_init_tree(Gogo* gogo, tree type_tree, bool is_clear)
-  { return this->type_->get_typed_init_tree(gogo, type_tree, is_clear); }
-
-  tree
   do_make_expression_tree(Translate_context* context, Expression_list* args,
 			  source_location location)
   { return this->type_->make_expression_tree(context, args, location); }
@@ -2774,10 +2721,6 @@ class Forward_declaration_type : public Type
   do_get_backend(Gogo* gogo);
 
   tree
-  do_get_init_tree(Gogo* gogo, tree type_tree, bool is_clear)
-  { return this->base()->get_typed_init_tree(gogo, type_tree, is_clear); }
-
-  tree
   do_make_expression_tree(Translate_context* context, Expression_list* args,
 			  source_location location)
   { return this->base()->make_expression_tree(context, args, location); }