Use the backend interface for select statements.

From-SVN: r172468

gcc/go/ChangeLog

+2011-04-14  Ian Lance Taylor  <iant@google.com>
+
+	* go-gcc.cc (Backend::error_statement): New function.
+
 2011-04-13  Ian Lance Taylor  <iant@google.com>
 
 	* Make-lang.in (go/gogo-tree.o): depend on $(GO_RUNTIME_H).

gcc/go/go-gcc.cc

@@ -167,6 +167,10 @@ class Gcc_backend : public Backend
   // Statements.
 
   Bstatement*
+  error_statement()
+  { return this->make_statement(error_mark_node); }
+
+  Bstatement*
   expression_statement(Bexpression*);
 
   Bstatement*

gcc/go/gofrontend/backend.h

@@ -107,6 +107,12 @@ class Backend
 
   // Statements.
 
+  // Create an error statement.  This is used for cases which should
+  // not occur in a correct program, in order to keep the compilation
+  // going without crashing.
+  virtual Bstatement*
+  error_statement() = 0;
+
   // Create an expression statement.
   virtual Bstatement*
   expression_statement(Bexpression*) = 0;

gcc/go/gofrontend/expressions.cc

@@ -3603,10 +3603,11 @@ Unsafe_type_conversion_expression::do_get_tree(Translate_context* context)
   else if (t->channel_type() != NULL)
     gcc_assert(et->channel_type() != NULL);
   else if (t->points_to() != NULL && t->points_to()->channel_type() != NULL)
-    gcc_assert(et->points_to() != NULL
-	       && et->points_to()->channel_type() != NULL);
+    gcc_assert((et->points_to() != NULL
+		&& et->points_to()->channel_type() != NULL)
+	       || et->is_nil_type());
   else if (t->is_unsafe_pointer_type())
-    gcc_assert(et->points_to() != NULL);
+    gcc_assert(et->points_to() != NULL || et->is_nil_type());
   else if (et->is_unsafe_pointer_type())
     gcc_assert(t->points_to() != NULL);
   else if (t->interface_type() != NULL && !t->interface_type()->is_empty())

gcc/go/gofrontend/runtime.cc

@@ -381,3 +381,12 @@ Runtime::map_iteration_type()
 
   return Type::make_array_type(runtime_function_type(RFT_POINTER), iexpr);
 }
+
+// Return the type used to pass a list of general channels to the
+// select runtime function.
+
+Type*
+Runtime::chanptr_type()
+{
+  return runtime_function_type(RFT_CHANPTR);
+}

gcc/go/gofrontend/runtime.h

@@ -30,15 +30,24 @@ class Runtime
     NUMBER_OF_FUNCTIONS
   };
 
+  // Make a call to a runtime function.
   static Call_expression*
   make_call(Function, source_location, int, ...);
 
+  // Convert all the types used by runtime functions to the backend
+  // representation.
   static void
   convert_types(Gogo*);
 
+  // Return the type used for iterations over maps.
   static Type*
   map_iteration_type();
 
+  // Return the type used to pass a list of general channels to the
+  // select runtime function.
+  static Type*
+  chanptr_type();
+
  private:
   static Named_object*
   runtime_declaration(Function);

gcc/go/gofrontend/statements.h

@@ -678,9 +678,9 @@ class Select_clauses
   bool
   may_fall_through() const;
 
-  // Return a tree implementing the select statement.
-  tree
-  get_tree(Translate_context*, Unnamed_label* break_label, source_location);
+  // Convert to the backend representation.
+  Bstatement*
+  get_backend(Translate_context*, Unnamed_label* break_label, source_location);
 
  private:
   // A single clause.
@@ -749,8 +749,8 @@ class Select_clauses
     may_fall_through() const;
 
     // Return a tree for the statements to execute.
-    tree
-    get_statements_tree(Translate_context*);
+    Bstatement*
+    get_statements_backend(Translate_context*);
 
    private:
     // The channel.
@@ -778,8 +778,10 @@ class Select_clauses
   };
 
   void
-  add_clause_tree(Translate_context*, int, Select_clause*, Unnamed_label*,
-		  tree*);
+  add_clause_backend(Translate_context*, source_location, int index,
+		     int case_value, Select_clause*, Unnamed_label*,
+		     std::vector<std::vector<Bexpression*> >* cases,
+		     std::vector<Bstatement*>* clauses);
 
   typedef std::vector<Select_clause> Clauses;