OSDN Git Service

compiler: Permit type B byte; type S []B; var v = S("x").
[pf3gnuchains/gcc-fork.git] / gcc / go / gofrontend / types.cc
index c596de9..055bd67 100644 (file)
@@ -474,6 +474,116 @@ Type::are_compatible_for_binop(const Type* lhs, const Type* rhs)
   return false;
 }
 
+// Return true if a value with type T1 may be compared with a value of
+// type T2.  IS_EQUALITY_OP is true for == or !=, false for <, etc.
+
+bool
+Type::are_compatible_for_comparison(bool is_equality_op, const Type *t1,
+                                   const Type *t2, std::string *reason)
+{
+  if (t1 != t2
+      && !Type::are_assignable(t1, t2, NULL)
+      && !Type::are_assignable(t2, t1, NULL))
+    {
+      if (reason != NULL)
+       *reason = "incompatible types in binary expression";
+      return false;
+    }
+
+  if (!is_equality_op)
+    {
+      if (t1->integer_type() == NULL
+         && t1->float_type() == NULL
+         && !t1->is_string_type())
+       {
+         if (reason != NULL)
+           *reason = _("invalid comparison of non-ordered type");
+         return false;
+       }
+    }
+  else if (t1->is_slice_type()
+          || t1->map_type() != NULL
+          || t1->function_type() != NULL
+          || t2->is_slice_type()
+          || t2->map_type() != NULL
+          || t2->function_type() != NULL)
+    {
+      if (!t1->is_nil_type() && !t2->is_nil_type())
+       {
+         if (reason != NULL)
+           {
+             if (t1->is_slice_type() || t2->is_slice_type())
+               *reason = _("slice can only be compared to nil");
+             else if (t1->map_type() != NULL || t2->map_type() != NULL)
+               *reason = _("map can only be compared to nil");
+             else
+               *reason = _("func can only be compared to nil");
+
+             // Match 6g error messages.
+             if (t1->interface_type() != NULL || t2->interface_type() != NULL)
+               {
+                 char buf[200];
+                 snprintf(buf, sizeof buf, _("invalid operation (%s)"),
+                          reason->c_str());
+                 *reason = buf;
+               }
+           }
+         return false;
+       }
+    }
+  else
+    {
+      if (!t1->is_boolean_type()
+         && t1->integer_type() == NULL
+         && t1->float_type() == NULL
+         && t1->complex_type() == NULL
+         && !t1->is_string_type()
+         && t1->points_to() == NULL
+         && t1->channel_type() == NULL
+         && t1->interface_type() == NULL
+         && t1->struct_type() == NULL
+         && t1->array_type() == NULL
+         && !t1->is_nil_type())
+       {
+         if (reason != NULL)
+           *reason = _("invalid comparison of non-comparable type");
+         return false;
+       }
+
+      if (t1->named_type() != NULL)
+       return t1->named_type()->named_type_is_comparable(reason);
+      else if (t2->named_type() != NULL)
+       return t2->named_type()->named_type_is_comparable(reason);
+      else if (t1->struct_type() != NULL)
+       {
+         const Struct_field_list* fields = t1->struct_type()->fields();
+         for (Struct_field_list::const_iterator p = fields->begin();
+              p != fields->end();
+              ++p)
+           {
+             if (!p->type()->is_comparable())
+               {
+                 if (reason != NULL)
+                   *reason = _("invalid comparison of non-comparable struct");
+                 return false;
+               }
+           }
+       }
+      else if (t1->array_type() != NULL)
+       {
+         if (t1->array_type()->length()->is_nil_expression()
+             || !t1->array_type()->element_type()->is_comparable())
+           {
+             if (reason != NULL)
+               *reason = _("invalid comparison of non-comparable array");
+             return false;
+           }
+       }
+    }
+
+  return true;
+}
+
 // Return true if a value with type RHS may be assigned to a variable
 // with type LHS.  If CHECK_HIDDEN_FIELDS is true, check whether any
 // hidden fields are modified.  If REASON is not NULL, set *REASON to
@@ -605,7 +715,7 @@ Type::are_assignable_check_hidden(const Type* lhs, const Type* rhs,
 bool
 Type::are_assignable(const Type* lhs, const Type* rhs, std::string* reason)
 {
-  return Type::are_assignable_check_hidden(lhs, rhs, true, reason);
+  return Type::are_assignable_check_hidden(lhs, rhs, false, reason);
 }
 
 // Like are_assignable but don't check for hidden fields.
@@ -657,30 +767,27 @@ Type::are_convertible(const Type* lhs, const Type* rhs, std::string* reason)
   if (lhs->complex_type() != NULL && rhs->complex_type() != NULL)
     return true;
 
-  // An integer, or []byte, or []int, may be converted to a string.
+  // An integer, or []byte, or []rune, may be converted to a string.
   if (lhs->is_string_type())
     {
       if (rhs->integer_type() != NULL)
        return true;
-      if (rhs->is_slice_type() && rhs->named_type() == NULL)
+      if (rhs->is_slice_type())
        {
          const Type* e = rhs->array_type()->element_type()->forwarded();
          if (e->integer_type() != NULL
-             && (e == Type::lookup_integer_type("uint8")
-                 || e == Type::lookup_integer_type("int")))
+             && (e->integer_type()->is_byte()
+                 || e->integer_type()->is_rune()))
            return true;
        }
     }
 
-  // A string may be converted to []byte or []int.
-  if (rhs->is_string_type()
-      && lhs->is_slice_type()
-      && lhs->named_type() == NULL)
+  // A string may be converted to []byte or []rune.
+  if (rhs->is_string_type() && lhs->is_slice_type())
     {
       const Type* e = lhs->array_type()->element_type()->forwarded();
       if (e->integer_type() != NULL
-         && (e == Type::lookup_integer_type("uint8")
-             || e == Type::lookup_integer_type("int")))
+         && (e->integer_type()->is_byte() || e->integer_type()->is_rune()))
        return true;
     }
 
@@ -853,7 +960,7 @@ Type::get_btype_without_hash(Gogo* gogo)
 // Return a pointer to the type descriptor for this type.
 
 tree
-Type::type_descriptor_pointer(Gogo* gogo, source_location location)
+Type::type_descriptor_pointer(Gogo* gogo, Location location)
 {
   Type* t = this->forwarded();
   if (t->type_descriptor_var_ == NULL)
@@ -864,7 +971,7 @@ Type::type_descriptor_pointer(Gogo* gogo, source_location location)
   tree var_tree = var_to_tree(t->type_descriptor_var_);
   if (var_tree == error_mark_node)
     return error_mark_node;
-  return build_fold_addr_expr_loc(location, var_tree);
+  return build_fold_addr_expr_loc(location.gcc_location(), var_tree);
 }
 
 // A mapping from unnamed types to type descriptor variables.
@@ -899,44 +1006,17 @@ Type::make_type_descriptor_var(Gogo* gogo)
       phash = &ins.first->second;
     }
 
-  std::string var_name;
-  if (nt == NULL)
-    var_name = this->unnamed_type_descriptor_var_name(gogo);
-  else
-    var_name = this->type_descriptor_var_name(gogo);
+  std::string var_name = this->type_descriptor_var_name(gogo, nt);
 
   // Build the contents of the type descriptor.
   Expression* initializer = this->do_type_descriptor(gogo, NULL);
 
   Btype* initializer_btype = initializer->type()->get_backend(gogo);
 
-  // See if this type descriptor is defined in a different package.
-  bool is_defined_elsewhere = false;
-  if (nt != NULL)
-    {
-      if (nt->named_object()->package() != NULL)
-       {
-         // This is a named type defined in a different package.  The
-         // type descriptor should be defined in that package.
-         is_defined_elsewhere = true;
-       }
-    }
-  else
-    {
-      if (this->points_to() != NULL
-         && this->points_to()->named_type() != NULL
-         && this->points_to()->named_type()->named_object()->package() != NULL)
-       {
-         // This is an unnamed pointer to a named type defined in a
-         // different package.  The descriptor should be defined in
-         // that package.
-         is_defined_elsewhere = true;
-       }
-    }
-
-  source_location loc = nt == NULL ? BUILTINS_LOCATION : nt->location();
+  Location loc = nt == NULL ? Linemap::predeclared_location() : nt->location();
 
-  if (is_defined_elsewhere)
+  const Package* dummy;
+  if (this->type_descriptor_defined_elsewhere(nt, &dummy))
     {
       this->type_descriptor_var_ =
        gogo->backend()->immutable_struct_reference(var_name,
@@ -986,21 +1066,15 @@ Type::make_type_descriptor_var(Gogo* gogo)
                                             binitializer);
 }
 
-// Return the name of the type descriptor variable for an unnamed
-// type.
+// Return the name of the type descriptor variable.  If NT is not
+// NULL, use it to get the name.  Otherwise this is an unnamed type.
 
 std::string
-Type::unnamed_type_descriptor_var_name(Gogo* gogo)
+Type::type_descriptor_var_name(Gogo* gogo, Named_type* nt)
 {
-  return "__go_td_" + this->mangled_name(gogo);
-}
-
-// Return the name of the type descriptor variable for a named type.
+  if (nt == NULL)
+    return "__go_td_" + this->mangled_name(gogo);
 
-std::string
-Type::type_descriptor_var_name(Gogo* gogo)
-{
-  Named_type* nt = this->named_type();
   Named_object* no = nt->named_object();
   const Named_object* in_function = nt->in_function();
   std::string ret = "__go_tdn_";
@@ -1028,6 +1102,39 @@ Type::type_descriptor_var_name(Gogo* gogo)
   return ret;
 }
 
+// Return true if this type descriptor is defined in a different
+// package.  If this returns true it sets *PACKAGE to the package.
+
+bool
+Type::type_descriptor_defined_elsewhere(Named_type* nt,
+                                       const Package** package)
+{
+  if (nt != NULL)
+    {
+      if (nt->named_object()->package() != NULL)
+       {
+         // This is a named type defined in a different package.  The
+         // type descriptor should be defined in that package.
+         *package = nt->named_object()->package();
+         return true;
+       }
+    }
+  else
+    {
+      if (this->points_to() != NULL
+         && this->points_to()->named_type() != NULL
+         && this->points_to()->named_type()->named_object()->package() != NULL)
+       {
+         // This is an unnamed pointer to a named type defined in a
+         // different package.  The descriptor should be defined in
+         // that package.
+         *package = this->points_to()->named_type()->named_object()->package();
+         return true;
+       }
+    }
+  return false;
+}
+
 // Return a composite literal for a type descriptor.
 
 Expression*
@@ -1054,7 +1161,7 @@ Type::make_builtin_struct_type(int nfields, ...)
   va_list ap;
   va_start(ap, nfields);
 
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
   Struct_field_list* sfl = new Struct_field_list();
   for (int i = 0; i < nfields; i++)
     {
@@ -1077,7 +1184,7 @@ std::vector<Named_type*> Type::named_builtin_types;
 Named_type*
 Type::make_builtin_named_type(const char* name, Type* type)
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
   Named_object* no = Named_object::make_type(name, NULL, type, bloc);
   Named_type* ret = no->type_value();
   Type::named_builtin_types.push_back(ret);
@@ -1110,7 +1217,7 @@ Type::make_type_descriptor_type()
   static Type* ret;
   if (ret == NULL)
     {
-      source_location bloc = BUILTINS_LOCATION;
+      Location bloc = Linemap::predeclared_location();
 
       Type* uint8_type = Type::lookup_integer_type("uint8");
       Type* uint32_type = Type::lookup_integer_type("uint32");
@@ -1159,8 +1266,8 @@ Type::make_type_descriptor_type()
       // The type descriptor type.
 
       Typed_identifier_list* params = new Typed_identifier_list();
-      params->push_back(Typed_identifier("", unsafe_pointer_type, bloc));
-      params->push_back(Typed_identifier("", uintptr_type, bloc));
+      params->push_back(Typed_identifier("key", unsafe_pointer_type, bloc));
+      params->push_back(Typed_identifier("key_size", uintptr_type, bloc));
 
       Typed_identifier_list* results = new Typed_identifier_list();
       results->push_back(Typed_identifier("", uintptr_type, bloc));
@@ -1168,9 +1275,9 @@ Type::make_type_descriptor_type()
       Type* hashfn_type = Type::make_function_type(NULL, params, results, bloc);
 
       params = new Typed_identifier_list();
-      params->push_back(Typed_identifier("", unsafe_pointer_type, bloc));
-      params->push_back(Typed_identifier("", unsafe_pointer_type, bloc));
-      params->push_back(Typed_identifier("", uintptr_type, bloc));
+      params->push_back(Typed_identifier("key1", unsafe_pointer_type, bloc));
+      params->push_back(Typed_identifier("key2", unsafe_pointer_type, bloc));
+      params->push_back(Typed_identifier("key_size", uintptr_type, bloc));
 
       results = new Typed_identifier_list();
       results->push_back(Typed_identifier("", Type::lookup_bool_type(), bloc));
@@ -1215,69 +1322,290 @@ Type::make_type_descriptor_ptr_type()
   return ret;
 }
 
-// Return the names of runtime functions which compute a hash code for
-// this type and which compare whether two values of this type are
-// equal.
+// Set *HASH_FN and *EQUAL_FN to the runtime functions which compute a
+// hash code for this type and which compare whether two values of
+// this type are equal.  If NAME is not NULL it is the name of this
+// type.  HASH_FNTYPE and EQUAL_FNTYPE are the types of these
+// functions, for convenience; they may be NULL.
 
 void
-Type::type_functions(const char** hash_fn, const char** equal_fn) const
+Type::type_functions(Gogo* gogo, Named_type* name, Function_type* hash_fntype,
+                    Function_type* equal_fntype, Named_object** hash_fn,
+                    Named_object** equal_fn)
 {
-  switch (this->base()->classification())
+  if (hash_fntype == NULL || equal_fntype == NULL)
     {
-    case Type::TYPE_ERROR:
-    case Type::TYPE_VOID:
-    case Type::TYPE_NIL:
-      // These types can not be hashed or compared.
-      *hash_fn = "__go_type_hash_error";
-      *equal_fn = "__go_type_equal_error";
-      break;
+      Location bloc = Linemap::predeclared_location();
 
-    case Type::TYPE_BOOLEAN:
-    case Type::TYPE_INTEGER:
-    case Type::TYPE_FLOAT:
-    case Type::TYPE_COMPLEX:
-    case Type::TYPE_POINTER:
-    case Type::TYPE_FUNCTION:
-    case Type::TYPE_MAP:
-    case Type::TYPE_CHANNEL:
-      *hash_fn = "__go_type_hash_identity";
-      *equal_fn = "__go_type_equal_identity";
-      break;
+      Type* uintptr_type = Type::lookup_integer_type("uintptr");
+      Type* void_type = Type::make_void_type();
+      Type* unsafe_pointer_type = Type::make_pointer_type(void_type);
 
-    case Type::TYPE_STRING:
-      *hash_fn = "__go_type_hash_string";
-      *equal_fn = "__go_type_equal_string";
-      break;
+      if (hash_fntype == NULL)
+       {
+         Typed_identifier_list* params = new Typed_identifier_list();
+         params->push_back(Typed_identifier("key", unsafe_pointer_type,
+                                            bloc));
+         params->push_back(Typed_identifier("key_size", uintptr_type, bloc));
 
-    case Type::TYPE_STRUCT:
-    case Type::TYPE_ARRAY:
-      // These types can not be hashed or compared.
-      *hash_fn = "__go_type_hash_error";
-      *equal_fn = "__go_type_equal_error";
-      break;
+         Typed_identifier_list* results = new Typed_identifier_list();
+         results->push_back(Typed_identifier("", uintptr_type, bloc));
 
-    case Type::TYPE_INTERFACE:
-      if (this->interface_type()->is_empty())
+         hash_fntype = Type::make_function_type(NULL, params, results, bloc);
+       }
+      if (equal_fntype == NULL)
        {
-         *hash_fn = "__go_type_hash_empty_interface";
-         *equal_fn = "__go_type_equal_empty_interface";
+         Typed_identifier_list* params = new Typed_identifier_list();
+         params->push_back(Typed_identifier("key1", unsafe_pointer_type,
+                                            bloc));
+         params->push_back(Typed_identifier("key2", unsafe_pointer_type,
+                                            bloc));
+         params->push_back(Typed_identifier("key_size", uintptr_type, bloc));
+
+         Typed_identifier_list* results = new Typed_identifier_list();
+         results->push_back(Typed_identifier("", Type::lookup_bool_type(),
+                                             bloc));
+
+         equal_fntype = Type::make_function_type(NULL, params, results, bloc);
        }
-      else
+    }
+
+  const char* hash_fnname;
+  const char* equal_fnname;
+  if (this->compare_is_identity(gogo))
+    {
+      hash_fnname = "__go_type_hash_identity";
+      equal_fnname = "__go_type_equal_identity";
+    }
+  else if (!this->is_comparable())
+    {
+      hash_fnname = "__go_type_hash_error";
+      equal_fnname = "__go_type_equal_error";
+    }
+  else
+    {
+      switch (this->base()->classification())
        {
-         *hash_fn = "__go_type_hash_interface";
-         *equal_fn = "__go_type_equal_interface";
+       case Type::TYPE_ERROR:
+       case Type::TYPE_VOID:
+       case Type::TYPE_NIL:
+       case Type::TYPE_FUNCTION:
+       case Type::TYPE_MAP:
+         // For these types is_comparable should have returned false.
+         go_unreachable();
+
+       case Type::TYPE_BOOLEAN:
+       case Type::TYPE_INTEGER:
+       case Type::TYPE_POINTER:
+       case Type::TYPE_CHANNEL:
+         // For these types compare_is_identity should have returned true.
+         go_unreachable();
+
+       case Type::TYPE_FLOAT:
+         hash_fnname = "__go_type_hash_float";
+         equal_fnname = "__go_type_equal_float";
+         break;
+
+       case Type::TYPE_COMPLEX:
+         hash_fnname = "__go_type_hash_complex";
+         equal_fnname = "__go_type_equal_complex";
+         break;
+
+       case Type::TYPE_STRING:
+         hash_fnname = "__go_type_hash_string";
+         equal_fnname = "__go_type_equal_string";
+         break;
+
+       case Type::TYPE_STRUCT:
+         {
+           // This is a struct which can not be compared using a
+           // simple identity function.  We need to build a function
+           // for comparison.
+           this->specific_type_functions(gogo, name, hash_fntype,
+                                         equal_fntype, hash_fn, equal_fn);
+           return;
+         }
+
+       case Type::TYPE_ARRAY:
+         if (this->is_slice_type())
+           {
+             // Type::is_compatible_for_comparison should have
+             // returned false.
+             go_unreachable();
+           }
+         else
+           {
+             // This is an array which can not be compared using a
+             // simple identity function.  We need to build a
+             // function for comparison.
+             this->specific_type_functions(gogo, name, hash_fntype,
+                                           equal_fntype, hash_fn, equal_fn);
+             return;
+           }
+         break;
+
+       case Type::TYPE_INTERFACE:
+         if (this->interface_type()->is_empty())
+           {
+             hash_fnname = "__go_type_hash_empty_interface";
+             equal_fnname = "__go_type_equal_empty_interface";
+           }
+         else
+           {
+             hash_fnname = "__go_type_hash_interface";
+             equal_fnname = "__go_type_equal_interface";
+           }
+         break;
+
+       case Type::TYPE_NAMED:
+       case Type::TYPE_FORWARD:
+         go_unreachable();
+
+       default:
+         go_unreachable();
        }
-      break;
+    }
 
-    case Type::TYPE_NAMED:
-    case Type::TYPE_FORWARD:
-      go_unreachable();
 
-    default:
-      go_unreachable();
+  Location bloc = Linemap::predeclared_location();
+  *hash_fn = Named_object::make_function_declaration(hash_fnname, NULL,
+                                                    hash_fntype, bloc);
+  (*hash_fn)->func_declaration_value()->set_asm_name(hash_fnname);
+  *equal_fn = Named_object::make_function_declaration(equal_fnname, NULL,
+                                                     equal_fntype, bloc);
+  (*equal_fn)->func_declaration_value()->set_asm_name(equal_fnname);
+}
+
+// A hash table mapping types to the specific hash functions.
+
+Type::Type_functions Type::type_functions_table;
+
+// Handle a type function which is specific to a type: a struct or
+// array which can not use an identity comparison.
+
+void
+Type::specific_type_functions(Gogo* gogo, Named_type* name,
+                             Function_type* hash_fntype,
+                             Function_type* equal_fntype,
+                             Named_object** hash_fn,
+                             Named_object** equal_fn)
+{
+  Hash_equal_fn fnull(NULL, NULL);
+  std::pair<Type*, Hash_equal_fn> val(name != NULL ? name : this, fnull);
+  std::pair<Type_functions::iterator, bool> ins =
+    Type::type_functions_table.insert(val);
+  if (!ins.second)
+    {
+      // We already have functions for this type
+      *hash_fn = ins.first->second.first;
+      *equal_fn = ins.first->second.second;
+      return;
+    }
+
+  std::string base_name;
+  if (name == NULL)
+    {
+      // Mangled names can have '.' if they happen to refer to named
+      // types in some way.  That's fine if this is simply a named
+      // type, but otherwise it will confuse the code that builds
+      // function identifiers.  Remove '.' when necessary.
+      base_name = this->mangled_name(gogo);
+      size_t i;
+      while ((i = base_name.find('.')) != std::string::npos)
+       base_name[i] = '$';
+      base_name = gogo->pack_hidden_name(base_name, false);
+    }
+  else
+    {
+      // This name is already hidden or not as appropriate.
+      base_name = name->name();
+      const Named_object* in_function = name->in_function();
+      if (in_function != NULL)
+       base_name += '$' + in_function->name();
+    }
+  std::string hash_name = base_name + "$hash";
+  std::string equal_name = base_name + "$equal";
+
+  Location bloc = Linemap::predeclared_location();
+
+  const Package* package = NULL;
+  bool is_defined_elsewhere =
+    this->type_descriptor_defined_elsewhere(name, &package);
+  if (is_defined_elsewhere)
+    {
+      *hash_fn = Named_object::make_function_declaration(hash_name, package,
+                                                        hash_fntype, bloc);
+      *equal_fn = Named_object::make_function_declaration(equal_name, package,
+                                                         equal_fntype, bloc);
+    }
+  else
+    {
+      *hash_fn = gogo->declare_package_function(hash_name, hash_fntype, bloc);
+      *equal_fn = gogo->declare_package_function(equal_name, equal_fntype,
+                                                bloc);
+    }
+
+  ins.first->second.first = *hash_fn;
+  ins.first->second.second = *equal_fn;
+
+  if (!is_defined_elsewhere)
+    {
+      if (gogo->in_global_scope())
+       this->write_specific_type_functions(gogo, name, hash_name, hash_fntype,
+                                           equal_name, equal_fntype);
+      else
+       gogo->queue_specific_type_function(this, name, hash_name, hash_fntype,
+                                          equal_name, equal_fntype);
     }
 }
 
+// Write the hash and equality functions for a type which needs to be
+// written specially.
+
+void
+Type::write_specific_type_functions(Gogo* gogo, Named_type* name,
+                                   const std::string& hash_name,
+                                   Function_type* hash_fntype,
+                                   const std::string& equal_name,
+                                   Function_type* equal_fntype)
+{
+  Location bloc = Linemap::predeclared_location();
+
+  Named_object* hash_fn = gogo->start_function(hash_name, hash_fntype, false,
+                                              bloc);
+  gogo->start_block(bloc);
+
+  if (this->struct_type() != NULL)
+    this->struct_type()->write_hash_function(gogo, name, hash_fntype,
+                                            equal_fntype);
+  else if (this->array_type() != NULL)
+    this->array_type()->write_hash_function(gogo, name, hash_fntype,
+                                           equal_fntype);
+  else
+    go_unreachable();
+
+  Block* b = gogo->finish_block(bloc);
+  gogo->add_block(b, bloc);
+  gogo->lower_block(hash_fn, b);
+  gogo->finish_function(bloc);
+
+  Named_object *equal_fn = gogo->start_function(equal_name, equal_fntype,
+                                               false, bloc);
+  gogo->start_block(bloc);
+
+  if (this->struct_type() != NULL)
+    this->struct_type()->write_equal_function(gogo, name);
+  else if (this->array_type() != NULL)
+    this->array_type()->write_equal_function(gogo, name);
+  else
+    go_unreachable();
+
+  b = gogo->finish_block(bloc);
+  gogo->add_block(b, bloc);
+  gogo->lower_block(equal_fn, b);
+  gogo->finish_function(bloc);
+}
+
 // Return a composite literal for the type descriptor for a plain type
 // of kind RUNTIME_TYPE_KIND named NAME.
 
@@ -1286,7 +1614,7 @@ Type::type_descriptor_constructor(Gogo* gogo, int runtime_type_kind,
                                  Named_type* name, const Methods* methods,
                                  bool only_value_methods)
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   Type* td_type = Type::make_type_descriptor_type();
   const Struct_field_list* fields = td_type->struct_type()->fields();
@@ -1322,25 +1650,20 @@ Type::type_descriptor_constructor(Gogo* gogo, int runtime_type_kind,
   mpz_set_ui(iv, this->hash_for_method(gogo));
   vals->push_back(Expression::make_integer(&iv, p->type(), bloc));
 
-  const char* hash_fn;
-  const char* equal_fn;
-  this->type_functions(&hash_fn, &equal_fn);
-
   ++p;
   go_assert(p->is_field_name("hashfn"));
-  Function_type* fntype = p->type()->function_type();
-  Named_object* no = Named_object::make_function_declaration(hash_fn, NULL,
-                                                            fntype,
-                                                            bloc);
-  no->func_declaration_value()->set_asm_name(hash_fn);
-  vals->push_back(Expression::make_func_reference(no, NULL, bloc));
+  Function_type* hash_fntype = p->type()->function_type();
 
   ++p;
   go_assert(p->is_field_name("equalfn"));
-  fntype = p->type()->function_type();
-  no = Named_object::make_function_declaration(equal_fn, NULL, fntype, bloc);
-  no->func_declaration_value()->set_asm_name(equal_fn);
-  vals->push_back(Expression::make_func_reference(no, NULL, bloc));
+  Function_type* equal_fntype = p->type()->function_type();
+
+  Named_object* hash_fn;
+  Named_object* equal_fn;
+  this->type_functions(gogo, name, hash_fntype, equal_fntype, &hash_fn,
+                      &equal_fn);
+  vals->push_back(Expression::make_func_reference(hash_fn, NULL, bloc));
+  vals->push_back(Expression::make_func_reference(equal_fn, NULL, bloc));
 
   ++p;
   go_assert(p->is_field_name("string"));
@@ -1394,7 +1717,7 @@ Type::uncommon_type_constructor(Gogo* gogo, Type* uncommon_type,
                                Named_type* name, const Methods* methods,
                                bool only_value_methods) const
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   const Struct_field_list* fields = uncommon_type->struct_type()->fields();
 
@@ -1477,7 +1800,7 @@ Type::methods_constructor(Gogo* gogo, Type* methods_type,
                          const Methods* methods,
                          bool only_value_methods) const
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   std::vector<std::pair<std::string, const Method*> > smethods;
   if (methods != NULL)
@@ -1524,7 +1847,7 @@ Type::method_constructor(Gogo*, Type* method_type,
                         const Method* m,
                         bool only_value_methods) const
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   const Struct_field_list* fields = method_type->struct_type()->fields();
 
@@ -1637,6 +1960,126 @@ Type::mangled_name(Gogo* gogo) const
   return ret;
 }
 
+// Return whether the backend size of the type is known.
+
+bool
+Type::is_backend_type_size_known(Gogo* gogo)
+{
+  switch (this->classification_)
+    {
+    case TYPE_ERROR:
+    case TYPE_VOID:
+    case TYPE_BOOLEAN:
+    case TYPE_INTEGER:
+    case TYPE_FLOAT:
+    case TYPE_COMPLEX:
+    case TYPE_STRING:
+    case TYPE_FUNCTION:
+    case TYPE_POINTER:
+    case TYPE_NIL:
+    case TYPE_MAP:
+    case TYPE_CHANNEL:
+    case TYPE_INTERFACE:
+      return true;
+
+    case TYPE_STRUCT:
+      {
+       const Struct_field_list* fields = this->struct_type()->fields();
+       for (Struct_field_list::const_iterator pf = fields->begin();
+            pf != fields->end();
+            ++pf)
+         if (!pf->type()->is_backend_type_size_known(gogo))
+           return false;
+       return true;
+      }
+
+    case TYPE_ARRAY:
+      {
+       const Array_type* at = this->array_type();
+       if (at->length() == NULL)
+         return true;
+       else
+         {
+           mpz_t ival;
+           mpz_init(ival);
+           Type* dummy;
+           bool length_known = at->length()->integer_constant_value(true,
+                                                                    ival,
+                                                                    &dummy);
+           mpz_clear(ival);
+           if (!length_known)
+             return false;
+           return at->element_type()->is_backend_type_size_known(gogo);
+         }
+      }
+
+    case TYPE_NAMED:
+      // Begin converting this type to the backend representation.
+      // This will create a placeholder if necessary.
+      this->get_backend(gogo);
+      return this->named_type()->is_named_backend_type_size_known();
+
+    case TYPE_FORWARD:
+      {
+       Forward_declaration_type* fdt = this->forward_declaration_type();
+       return fdt->real_type()->is_backend_type_size_known(gogo);
+      }
+
+    case TYPE_SINK:
+    case TYPE_CALL_MULTIPLE_RESULT:
+      go_unreachable();
+
+    default:
+      go_unreachable();
+    }
+}
+
+// If the size of the type can be determined, set *PSIZE to the size
+// in bytes and return true.  Otherwise, return false.  This queries
+// the backend.
+
+bool
+Type::backend_type_size(Gogo* gogo, unsigned int *psize)
+{
+  if (!this->is_backend_type_size_known(gogo))
+    return false;
+  size_t size = gogo->backend()->type_size(this->get_backend(gogo));
+  *psize = static_cast<unsigned int>(size);
+  if (*psize != size)
+    return false;
+  return true;
+}
+
+// If the alignment of the type can be determined, set *PALIGN to
+// the alignment in bytes and return true.  Otherwise, return false.
+
+bool
+Type::backend_type_align(Gogo* gogo, unsigned int *palign)
+{
+  if (!this->is_backend_type_size_known(gogo))
+    return false;
+  size_t align = gogo->backend()->type_alignment(this->get_backend(gogo));
+  *palign = static_cast<unsigned int>(align);
+  if (*palign != align)
+    return false;
+  return true;
+}
+
+// Like backend_type_align, but return the alignment when used as a
+// field.
+
+bool
+Type::backend_type_field_align(Gogo* gogo, unsigned int *palign)
+{
+  if (!this->is_backend_type_size_known(gogo))
+    return false;
+  size_t a = gogo->backend()->type_field_alignment(this->get_backend(gogo));
+  *palign = static_cast<unsigned int>(a);
+  if (*palign != a)
+    return false;
+  return true;
+}
+
 // Default function to export a type.
 
 void
@@ -1682,13 +2125,17 @@ class Error_type : public Type
   { }
 
  protected:
+  bool
+  do_compare_is_identity(Gogo*) const
+  { return false; }
+
   Btype*
   do_get_backend(Gogo* gogo)
   { return gogo->backend()->error_type(); }
 
   Expression*
   do_type_descriptor(Gogo*, Named_type*)
-  { return Expression::make_error(BUILTINS_LOCATION); }
+  { return Expression::make_error(Linemap::predeclared_location()); }
 
   void
   do_reflection(Gogo*, std::string*) const
@@ -1716,6 +2163,10 @@ class Void_type : public Type
   { }
 
  protected:
+  bool
+  do_compare_is_identity(Gogo*) const
+  { return false; }
+
   Btype*
   do_get_backend(Gogo* gogo)
   { return gogo->backend()->void_type(); }
@@ -1750,6 +2201,10 @@ class Boolean_type : public Type
   { }
 
  protected:
+  bool
+  do_compare_is_identity(Gogo*) const
+  { return true; }
+
   Btype*
   do_get_backend(Gogo* gogo)
   { return gogo->backend()->bool_type(); }
@@ -1807,9 +2262,9 @@ Named_type*
 Type::make_named_bool_type()
 {
   Type* bool_type = Type::make_boolean_type();
-  Named_object* named_object = Named_object::make_type("bool", NULL,
-                                                      bool_type,
-                                                      BUILTINS_LOCATION);
+  Named_object* named_object =
+    Named_object::make_type("bool", NULL, bool_type,
+                            Linemap::predeclared_location());
   Named_type* named_type = named_object->type_value();
   named_bool_type = named_type;
   return named_type;
@@ -1829,9 +2284,9 @@ Integer_type::create_integer_type(const char* name, bool is_unsigned,
   Integer_type* integer_type = new Integer_type(false, is_unsigned, bits,
                                                runtime_type_kind);
   std::string sname(name);
-  Named_object* named_object = Named_object::make_type(sname, NULL,
-                                                      integer_type,
-                                                      BUILTINS_LOCATION);
+  Named_object* named_object =
+    Named_object::make_type(sname, NULL, integer_type,
+                            Linemap::predeclared_location());
   Named_type* named_type = named_object->type_value();
   std::pair<Named_integer_types::iterator, bool> ins =
     Integer_type::named_integer_types.insert(std::make_pair(sname, named_type));
@@ -1965,8 +2420,9 @@ Float_type::create_float_type(const char* name, int bits,
 {
   Float_type* float_type = new Float_type(false, bits, runtime_type_kind);
   std::string sname(name);
-  Named_object* named_object = Named_object::make_type(sname, NULL, float_type,
-                                                      BUILTINS_LOCATION);
+  Named_object* named_object =
+    Named_object::make_type(sname, NULL, float_type,
+                            Linemap::predeclared_location());
   Named_type* named_type = named_object->type_value();
   std::pair<Named_float_types::iterator, bool> ins =
     Float_type::named_float_types.insert(std::make_pair(sname, named_type));
@@ -2089,9 +2545,9 @@ Complex_type::create_complex_type(const char* name, int bits,
   Complex_type* complex_type = new Complex_type(false, bits,
                                                runtime_type_kind);
   std::string sname(name);
-  Named_object* named_object = Named_object::make_type(sname, NULL,
-                                                      complex_type,
-                                                      BUILTINS_LOCATION);
+  Named_object* named_object =
+    Named_object::make_type(sname, NULL, complex_type,
+                            Linemap::predeclared_location());
   Named_type* named_type = named_object->type_value();
   std::pair<Named_complex_types::iterator, bool> ins =
     Complex_type::named_complex_types.insert(std::make_pair(sname,
@@ -2219,12 +2675,12 @@ String_type::do_get_backend(Gogo* gogo)
       Type* pb = Type::make_pointer_type(b);
       fields[0].name = "__data";
       fields[0].btype = pb->get_backend(gogo);
-      fields[0].location = UNKNOWN_LOCATION;
+      fields[0].location = Linemap::predeclared_location();
 
       Type* int_type = Type::lookup_integer_type("int");
       fields[1].name = "__length";
       fields[1].btype = int_type->get_backend(gogo);
-      fields[1].location = UNKNOWN_LOCATION;
+      fields[1].location = fields[0].location;
 
       backend_string_type = gogo->backend()->struct_type(fields);
     }
@@ -2317,9 +2773,9 @@ Named_type*
 Type::make_named_string_type()
 {
   Type* string_type = Type::make_string_type();
-  Named_object* named_object = Named_object::make_type("string", NULL,
-                                                      string_type,
-                                                      BUILTINS_LOCATION);
+  Named_object* named_object =
+    Named_object::make_type("string", NULL, string_type,
+                            Linemap::predeclared_location());
   Named_type* named_type = named_object->type_value();
   named_string_type = named_type;
   return named_type;
@@ -2336,6 +2792,10 @@ class Sink_type : public Type
   { }
 
  protected:
+  bool
+  do_compare_is_identity(Gogo*) const
+  { return false; }
+
   Btype*
   do_get_backend(Gogo*)
   { go_unreachable(); }
@@ -2742,7 +3202,7 @@ Function_type::make_function_type_descriptor_type()
 Expression*
 Function_type::do_type_descriptor(Gogo* gogo, Named_type* name)
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   Type* ftdt = Function_type::make_function_type_descriptor_type();
 
@@ -2785,7 +3245,7 @@ Function_type::type_descriptor_params(Type* params_type,
                                      const Typed_identifier* receiver,
                                      const Typed_identifier_list* params)
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   if (receiver == NULL && params == NULL)
     return Expression::make_slice_composite_literal(params_type, NULL, bloc);
@@ -3073,7 +3533,7 @@ Function_type*
 Type::make_function_type(Typed_identifier* receiver,
                         Typed_identifier_list* parameters,
                         Typed_identifier_list* results,
-                        source_location location)
+                        Location location)
 {
   return new Function_type(receiver, parameters, results, location);
 }
@@ -3140,7 +3600,7 @@ Pointer_type::do_type_descriptor(Gogo* gogo, Named_type* name)
     }
   else
     {
-      source_location bloc = BUILTINS_LOCATION;
+      Location bloc = Linemap::predeclared_location();
 
       const Methods* methods;
       Type* deref = this->points_to();
@@ -3244,6 +3704,10 @@ class Nil_type : public Type
   { }
 
  protected:
+  bool
+  do_compare_is_identity(Gogo*) const
+  { return false; }
+
   Btype*
   do_get_backend(Gogo* gogo)
   { return gogo->backend()->pointer_type(gogo->backend()->void_type()); }
@@ -3291,6 +3755,10 @@ class Call_multiple_result_type : public Type
     return false;
   }
 
+  bool
+  do_compare_is_identity(Gogo*) const
+  { return false; }
+
   Btype*
   do_get_backend(Gogo* gogo)
   {
@@ -3302,7 +3770,7 @@ class Call_multiple_result_type : public Type
   do_type_descriptor(Gogo*, Named_type*)
   {
     go_assert(saw_errors());
-    return Expression::make_error(UNKNOWN_LOCATION);
+    return Expression::make_error(Linemap::unknown_location());
   }
 
   void
@@ -3565,6 +4033,44 @@ Struct_type::struct_has_hidden_fields(const Named_type* within,
   return false;
 }
 
+// Whether comparisons of this struct type are simple identity
+// comparisons.
+
+bool
+Struct_type::do_compare_is_identity(Gogo* gogo) const
+{
+  const Struct_field_list* fields = this->fields_;
+  if (fields == NULL)
+    return true;
+  unsigned int offset = 0;
+  for (Struct_field_list::const_iterator pf = fields->begin();
+       pf != fields->end();
+       ++pf)
+    {
+      if (!pf->type()->compare_is_identity(gogo))
+       return false;
+
+      unsigned int field_align;
+      if (!pf->type()->backend_type_align(gogo, &field_align))
+       return false;
+      if ((offset & (field_align - 1)) != 0)
+       {
+         // This struct has padding.  We don't guarantee that that
+         // padding is zero-initialized for a stack variable, so we
+         // can't use memcmp to compare struct values.
+         return false;
+       }
+
+      unsigned int field_size;
+      if (!pf->type()->backend_type_size(gogo, &field_size))
+       return false;
+      offset += field_size;
+    }
+  return true;
+}
+
+// Build identity and hash functions for this struct.
+
 // Hash code.
 
 unsigned int
@@ -3609,7 +4115,7 @@ Struct_type::find_local_field(const std::string& name,
 
 Field_reference_expression*
 Struct_type::field_reference(Expression* struct_expr, const std::string& name,
-                            source_location location) const
+                            Location location) const
 {
   unsigned int depth;
   return this->field_reference_depth(struct_expr, name, location, NULL,
@@ -3622,7 +4128,7 @@ Struct_type::field_reference(Expression* struct_expr, const std::string& name,
 Field_reference_expression*
 Struct_type::field_reference_depth(Expression* struct_expr,
                                   const std::string& name,
-                                  source_location location,
+                                  Location location,
                                   Saw_named_type* saw,
                                   unsigned int* depth) const
 {
@@ -3744,7 +4250,7 @@ Struct_type::total_field_count() const
        pf != this->fields_->end();
        ++pf)
     {
-      if (!pf->is_anonymous() || pf->type()->deref()->struct_type() == NULL)
+      if (!pf->is_anonymous() || pf->type()->struct_type() == NULL)
        ++ret;
       else
        ret += pf->type()->struct_type()->total_field_count();
@@ -3867,7 +4373,7 @@ Struct_type::make_struct_type_descriptor_type()
 Expression*
 Struct_type::do_type_descriptor(Gogo* gogo, Named_type* name)
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   Type* stdt = Struct_type::make_struct_type_descriptor_type();
 
@@ -3953,6 +4459,170 @@ Struct_type::do_type_descriptor(Gogo* gogo, Named_type* name)
   return Expression::make_struct_composite_literal(stdt, vals, bloc);
 }
 
+// Write the hash function for a struct which can not use the identity
+// function.
+
+void
+Struct_type::write_hash_function(Gogo* gogo, Named_type*,
+                                Function_type* hash_fntype,
+                                Function_type* equal_fntype)
+{
+  Location bloc = Linemap::predeclared_location();
+
+  // The pointer to the struct that we are going to hash.  This is an
+  // argument to the hash function we are implementing here.
+  Named_object* key_arg = gogo->lookup("key", NULL);
+  go_assert(key_arg != NULL);
+  Type* key_arg_type = key_arg->var_value()->type();
+
+  Type* uintptr_type = Type::lookup_integer_type("uintptr");
+
+  // Get a 0.
+  mpz_t ival;
+  mpz_init_set_ui(ival, 0);
+  Expression* zero = Expression::make_integer(&ival, uintptr_type, bloc);
+  mpz_clear(ival);
+
+  // Make a temporary to hold the return value, initialized to 0.
+  Temporary_statement* retval = Statement::make_temporary(uintptr_type, zero,
+                                                         bloc);
+  gogo->add_statement(retval);
+
+  // Make a temporary to hold the key as a uintptr.
+  Expression* ref = Expression::make_var_reference(key_arg, bloc);
+  ref = Expression::make_cast(uintptr_type, ref, bloc);
+  Temporary_statement* key = Statement::make_temporary(uintptr_type, ref,
+                                                      bloc);
+  gogo->add_statement(key);
+
+  // Loop over the struct fields.
+  bool first = true;
+  const Struct_field_list* fields = this->fields_;
+  for (Struct_field_list::const_iterator pf = fields->begin();
+       pf != fields->end();
+       ++pf)
+    {
+      if (first)
+       first = false;
+      else
+       {
+         // Multiply retval by 33.
+         mpz_init_set_ui(ival, 33);
+         Expression* i33 = Expression::make_integer(&ival, uintptr_type,
+                                                    bloc);
+         mpz_clear(ival);
+
+         ref = Expression::make_temporary_reference(retval, bloc);
+         Statement* s = Statement::make_assignment_operation(OPERATOR_MULTEQ,
+                                                             ref, i33, bloc);
+         gogo->add_statement(s);
+       }
+
+      // Get a pointer to the value of this field.
+      Expression* offset = Expression::make_struct_field_offset(this, &*pf);
+      ref = Expression::make_temporary_reference(key, bloc);
+      Expression* subkey = Expression::make_binary(OPERATOR_PLUS, ref, offset,
+                                                  bloc);
+      subkey = Expression::make_cast(key_arg_type, subkey, bloc);
+
+      // Get the size of this field.
+      Expression* size = Expression::make_type_info(pf->type(),
+                                                   Expression::TYPE_INFO_SIZE);
+
+      // Get the hash function to use for the type of this field.
+      Named_object* hash_fn;
+      Named_object* equal_fn;
+      pf->type()->type_functions(gogo, pf->type()->named_type(), hash_fntype,
+                                equal_fntype, &hash_fn, &equal_fn);
+
+      // Call the hash function for the field.
+      Expression_list* args = new Expression_list();
+      args->push_back(subkey);
+      args->push_back(size);
+      Expression* func = Expression::make_func_reference(hash_fn, NULL, bloc);
+      Expression* call = Expression::make_call(func, args, false, bloc);
+
+      // Add the field's hash value to retval.
+      Temporary_reference_expression* tref =
+       Expression::make_temporary_reference(retval, bloc);
+      tref->set_is_lvalue();
+      Statement* s = Statement::make_assignment_operation(OPERATOR_PLUSEQ,
+                                                         tref, call, bloc);
+      gogo->add_statement(s);
+    }
+
+  // Return retval to the caller of the hash function.
+  Expression_list* vals = new Expression_list();
+  ref = Expression::make_temporary_reference(retval, bloc);
+  vals->push_back(ref);
+  Statement* s = Statement::make_return_statement(vals, bloc);
+  gogo->add_statement(s);
+}
+
+// Write the equality function for a struct which can not use the
+// identity function.
+
+void
+Struct_type::write_equal_function(Gogo* gogo, Named_type* name)
+{
+  Location bloc = Linemap::predeclared_location();
+
+  // The pointers to the structs we are going to compare.
+  Named_object* key1_arg = gogo->lookup("key1", NULL);
+  Named_object* key2_arg = gogo->lookup("key2", NULL);
+  go_assert(key1_arg != NULL && key2_arg != NULL);
+
+  // Build temporaries with the right types.
+  Type* pt = Type::make_pointer_type(name != NULL
+                                    ? static_cast<Type*>(name)
+                                    : static_cast<Type*>(this));
+
+  Expression* ref = Expression::make_var_reference(key1_arg, bloc);
+  ref = Expression::make_unsafe_cast(pt, ref, bloc);
+  Temporary_statement* p1 = Statement::make_temporary(pt, ref, bloc);
+  gogo->add_statement(p1);
+
+  ref = Expression::make_var_reference(key2_arg, bloc);
+  ref = Expression::make_unsafe_cast(pt, ref, bloc);
+  Temporary_statement* p2 = Statement::make_temporary(pt, ref, bloc);
+  gogo->add_statement(p2);
+
+  const Struct_field_list* fields = this->fields_;
+  unsigned int field_index = 0;
+  for (Struct_field_list::const_iterator pf = fields->begin();
+       pf != fields->end();
+       ++pf, ++field_index)
+    {
+      // Compare one field in both P1 and P2.
+      Expression* f1 = Expression::make_temporary_reference(p1, bloc);
+      f1 = Expression::make_unary(OPERATOR_MULT, f1, bloc);
+      f1 = Expression::make_field_reference(f1, field_index, bloc);
+
+      Expression* f2 = Expression::make_temporary_reference(p2, bloc);
+      f2 = Expression::make_unary(OPERATOR_MULT, f2, bloc);
+      f2 = Expression::make_field_reference(f2, field_index, bloc);
+
+      Expression* cond = Expression::make_binary(OPERATOR_NOTEQ, f1, f2, bloc);
+
+      // If the values are not equal, return false.
+      gogo->start_block(bloc);
+      Expression_list* vals = new Expression_list();
+      vals->push_back(Expression::make_boolean(false, bloc));
+      Statement* s = Statement::make_return_statement(vals, bloc);
+      gogo->add_statement(s);
+      Block* then_block = gogo->finish_block(bloc);
+
+      s = Statement::make_if_statement(cond, then_block, NULL, bloc);
+      gogo->add_statement(s);
+    }
+
+  // All the fields are equal, so return true.
+  Expression_list* vals = new Expression_list();
+  vals->push_back(Expression::make_boolean(true, bloc));
+  Statement* s = Statement::make_return_statement(vals, bloc);
+  gogo->add_statement(s);
+}
+
 // Reflection string.
 
 void
@@ -4057,6 +4727,24 @@ Struct_type::do_mangled_name(Gogo* gogo, std::string* ret) const
   ret->push_back('e');
 }
 
+// If the offset of field INDEX in the backend implementation can be
+// determined, set *POFFSET to the offset in bytes and return true.
+// Otherwise, return false.
+
+bool
+Struct_type::backend_field_offset(Gogo* gogo, unsigned int index,
+                                 unsigned int* poffset)
+{
+  if (!this->is_backend_type_size_known(gogo))
+    return false;
+  size_t offset = gogo->backend()->type_field_offset(this->get_backend(gogo),
+                                                    index);
+  *poffset = static_cast<unsigned int>(offset);
+  if (*poffset != offset)
+    return false;
+  return true;
+}
+
 // Export.
 
 void
@@ -4081,8 +4769,8 @@ Struct_type::do_export(Export* exp) const
       if (p->has_tag())
        {
          exp->write_c_string(" ");
-         Expression* expr = Expression::make_string(p->tag(),
-                                                    BUILTINS_LOCATION);
+         Expression* expr =
+            Expression::make_string(p->tag(), Linemap::predeclared_location());
          expr->export_expression(exp);
          delete expr;
        }
@@ -4140,7 +4828,7 @@ Struct_type::do_import(Import* imp)
 
 Struct_type*
 Type::make_struct_type(Struct_field_list* fields,
-                      source_location location)
+                      Location location)
 {
   return new Struct_type(fields, location);
 }
@@ -4289,6 +4977,33 @@ Array_type::do_verify()
   return true;
 }
 
+// Whether we can use memcmp to compare this array.
+
+bool
+Array_type::do_compare_is_identity(Gogo* gogo) const
+{
+  if (this->length_ == NULL)
+    return false;
+
+  // Check for [...], which indicates that this is not a real type.
+  if (this->length_->is_nil_expression())
+    return false;
+
+  if (!this->element_type_->compare_is_identity(gogo))
+    return false;
+
+  // If there is any padding, then we can't use memcmp.
+  unsigned int size;
+  unsigned int align;
+  if (!this->element_type_->backend_type_size(gogo, &size)
+      || !this->element_type_->backend_type_align(gogo, &align))
+    return false;
+  if ((size & (align - 1)) != 0)
+    return false;
+
+  return true;
+}
+
 // Array type hash code.
 
 unsigned int
@@ -4299,6 +5014,198 @@ Array_type::do_hash_for_method(Gogo* gogo) const
   return this->element_type_->hash_for_method(gogo) + 1;
 }
 
+// Write the hash function for an array which can not use the identify
+// function.
+
+void
+Array_type::write_hash_function(Gogo* gogo, Named_type* name,
+                               Function_type* hash_fntype,
+                               Function_type* equal_fntype)
+{
+  Location bloc = Linemap::predeclared_location();
+
+  // The pointer to the array that we are going to hash.  This is an
+  // argument to the hash function we are implementing here.
+  Named_object* key_arg = gogo->lookup("key", NULL);
+  go_assert(key_arg != NULL);
+  Type* key_arg_type = key_arg->var_value()->type();
+
+  Type* uintptr_type = Type::lookup_integer_type("uintptr");
+
+  // Get a 0.
+  mpz_t ival;
+  mpz_init_set_ui(ival, 0);
+  Expression* zero = Expression::make_integer(&ival, uintptr_type, bloc);
+  mpz_clear(ival);
+
+  // Make a temporary to hold the return value, initialized to 0.
+  Temporary_statement* retval = Statement::make_temporary(uintptr_type, zero,
+                                                         bloc);
+  gogo->add_statement(retval);
+
+  // Make a temporary to hold the key as a uintptr.
+  Expression* ref = Expression::make_var_reference(key_arg, bloc);
+  ref = Expression::make_cast(uintptr_type, ref, bloc);
+  Temporary_statement* key = Statement::make_temporary(uintptr_type, ref,
+                                                      bloc);
+  gogo->add_statement(key);
+
+  // Loop over the array elements.
+  // for i = range a
+  Type* int_type = Type::lookup_integer_type("int");
+  Temporary_statement* index = Statement::make_temporary(int_type, NULL, bloc);
+  gogo->add_statement(index);
+
+  Expression* iref = Expression::make_temporary_reference(index, bloc);
+  Expression* aref = Expression::make_var_reference(key_arg, bloc);
+  Type* pt = Type::make_pointer_type(name != NULL
+                                    ? static_cast<Type*>(name)
+                                    : static_cast<Type*>(this));
+  aref = Expression::make_cast(pt, aref, bloc);
+  For_range_statement* for_range = Statement::make_for_range_statement(iref,
+                                                                      NULL,
+                                                                      aref,
+                                                                      bloc);
+
+  gogo->start_block(bloc);
+
+  // Multiply retval by 33.
+  mpz_init_set_ui(ival, 33);
+  Expression* i33 = Expression::make_integer(&ival, uintptr_type, bloc);
+  mpz_clear(ival);
+
+  ref = Expression::make_temporary_reference(retval, bloc);
+  Statement* s = Statement::make_assignment_operation(OPERATOR_MULTEQ, ref,
+                                                     i33, bloc);
+  gogo->add_statement(s);
+
+  // Get the hash function for the element type.
+  Named_object* hash_fn;
+  Named_object* equal_fn;
+  this->element_type_->type_functions(gogo, this->element_type_->named_type(),
+                                     hash_fntype, equal_fntype, &hash_fn,
+                                     &equal_fn);
+
+  // Get a pointer to this element in the loop.
+  Expression* subkey = Expression::make_temporary_reference(key, bloc);
+  subkey = Expression::make_cast(key_arg_type, subkey, bloc);
+
+  // Get the size of each element.
+  Expression* ele_size = Expression::make_type_info(this->element_type_,
+                                                   Expression::TYPE_INFO_SIZE);
+
+  // Get the hash of this element.
+  Expression_list* args = new Expression_list();
+  args->push_back(subkey);
+  args->push_back(ele_size);
+  Expression* func = Expression::make_func_reference(hash_fn, NULL, bloc);
+  Expression* call = Expression::make_call(func, args, false, bloc);
+
+  // Add the element's hash value to retval.
+  Temporary_reference_expression* tref =
+    Expression::make_temporary_reference(retval, bloc);
+  tref->set_is_lvalue();
+  s = Statement::make_assignment_operation(OPERATOR_PLUSEQ, tref, call, bloc);
+  gogo->add_statement(s);
+
+  // Increase the element pointer.
+  tref = Expression::make_temporary_reference(key, bloc);
+  tref->set_is_lvalue();
+  s = Statement::make_assignment_operation(OPERATOR_PLUSEQ, tref, ele_size,
+                                          bloc);
+
+  Block* statements = gogo->finish_block(bloc);
+
+  for_range->add_statements(statements);
+  gogo->add_statement(for_range);
+
+  // Return retval to the caller of the hash function.
+  Expression_list* vals = new Expression_list();
+  ref = Expression::make_temporary_reference(retval, bloc);
+  vals->push_back(ref);
+  s = Statement::make_return_statement(vals, bloc);
+  gogo->add_statement(s);
+}
+
+// Write the equality function for an array which can not use the
+// identity function.
+
+void
+Array_type::write_equal_function(Gogo* gogo, Named_type* name)
+{
+  Location bloc = Linemap::predeclared_location();
+
+  // The pointers to the arrays we are going to compare.
+  Named_object* key1_arg = gogo->lookup("key1", NULL);
+  Named_object* key2_arg = gogo->lookup("key2", NULL);
+  go_assert(key1_arg != NULL && key2_arg != NULL);
+
+  // Build temporaries for the keys with the right types.
+  Type* pt = Type::make_pointer_type(name != NULL
+                                    ? static_cast<Type*>(name)
+                                    : static_cast<Type*>(this));
+
+  Expression* ref = Expression::make_var_reference(key1_arg, bloc);
+  ref = Expression::make_unsafe_cast(pt, ref, bloc);
+  Temporary_statement* p1 = Statement::make_temporary(pt, ref, bloc);
+  gogo->add_statement(p1);
+
+  ref = Expression::make_var_reference(key2_arg, bloc);
+  ref = Expression::make_unsafe_cast(pt, ref, bloc);
+  Temporary_statement* p2 = Statement::make_temporary(pt, ref, bloc);
+  gogo->add_statement(p2);
+
+  // Loop over the array elements.
+  // for i = range a
+  Type* int_type = Type::lookup_integer_type("int");
+  Temporary_statement* index = Statement::make_temporary(int_type, NULL, bloc);
+  gogo->add_statement(index);
+
+  Expression* iref = Expression::make_temporary_reference(index, bloc);
+  Expression* aref = Expression::make_temporary_reference(p1, bloc);
+  For_range_statement* for_range = Statement::make_for_range_statement(iref,
+                                                                      NULL,
+                                                                      aref,
+                                                                      bloc);
+
+  gogo->start_block(bloc);
+
+  // Compare element in P1 and P2.
+  Expression* e1 = Expression::make_temporary_reference(p1, bloc);
+  e1 = Expression::make_unary(OPERATOR_MULT, e1, bloc);
+  ref = Expression::make_temporary_reference(index, bloc);
+  e1 = Expression::make_array_index(e1, ref, NULL, bloc);
+
+  Expression* e2 = Expression::make_temporary_reference(p2, bloc);
+  e2 = Expression::make_unary(OPERATOR_MULT, e2, bloc);
+  ref = Expression::make_temporary_reference(index, bloc);
+  e2 = Expression::make_array_index(e2, ref, NULL, bloc);
+
+  Expression* cond = Expression::make_binary(OPERATOR_NOTEQ, e1, e2, bloc);
+
+  // If the elements are not equal, return false.
+  gogo->start_block(bloc);
+  Expression_list* vals = new Expression_list();
+  vals->push_back(Expression::make_boolean(false, bloc));
+  Statement* s = Statement::make_return_statement(vals, bloc);
+  gogo->add_statement(s);
+  Block* then_block = gogo->finish_block(bloc);
+
+  s = Statement::make_if_statement(cond, then_block, NULL, bloc);
+  gogo->add_statement(s);
+
+  Block* statements = gogo->finish_block(bloc);
+
+  for_range->add_statements(statements);
+  gogo->add_statement(for_range);
+
+  // All the elements are equal, so return true.
+  vals = new Expression_list();
+  vals->push_back(Expression::make_boolean(true, bloc));
+  s = Statement::make_return_statement(vals, bloc);
+  gogo->add_statement(s);
+}
+
 // Get a tree for the length of a fixed array.  The length may be
 // computed using a function call, so we must only evaluate it once.
 
@@ -4356,23 +5263,24 @@ get_backend_slice_fields(Gogo* gogo, Array_type* type,
 
   Type* pet = Type::make_pointer_type(type->element_type());
   Btype* pbet = pet->get_backend(gogo);
+  Location ploc = Linemap::predeclared_location();
 
   Backend::Btyped_identifier* p = &(*bfields)[0];
   p->name = "__values";
   p->btype = pbet;
-  p->location = UNKNOWN_LOCATION;
+  p->location = ploc;
 
   Type* int_type = Type::lookup_integer_type("int");
 
   p = &(*bfields)[1];
   p->name = "__count";
   p->btype = int_type->get_backend(gogo);
-  p->location = UNKNOWN_LOCATION;
+  p->location = ploc;
 
   p = &(*bfields)[2];
   p->name = "__capacity";
   p->btype = int_type->get_backend(gogo);
-  p->location = UNKNOWN_LOCATION;
+  p->location = ploc;
 }
 
 // Get a tree for the type of this array.  A fixed array is simply
@@ -4579,7 +5487,7 @@ Array_type::do_type_descriptor(Gogo* gogo, Named_type* name)
 Expression*
 Array_type::array_type_descriptor(Gogo* gogo, Named_type* name)
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   Type* atdt = Array_type::make_array_type_descriptor_type();
 
@@ -4618,7 +5526,7 @@ Array_type::array_type_descriptor(Gogo* gogo, Named_type* name)
 Expression*
 Array_type::slice_type_descriptor(Gogo* gogo, Named_type* name)
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   Type* stdt = Array_type::make_slice_type_descriptor_type();
 
@@ -4730,8 +5638,8 @@ Map_type::do_traverse(Traverse* traverse)
 bool
 Map_type::do_verify()
 {
-  if (this->key_type_->struct_type() != NULL
-      || this->key_type_->array_type() != NULL)
+  // The runtime support uses "map[void]void".
+  if (!this->key_type_->is_comparable() && !this->key_type_->is_void_type())
     {
       error_at(this->location_, "invalid map key type");
       return false;
@@ -4772,29 +5680,31 @@ Map_type::do_get_backend(Gogo* gogo)
     {
       std::vector<Backend::Btyped_identifier> bfields(4);
 
+      Location bloc = Linemap::predeclared_location();
+
       Type* pdt = Type::make_type_descriptor_ptr_type();
       bfields[0].name = "__descriptor";
       bfields[0].btype = pdt->get_backend(gogo);
-      bfields[0].location = BUILTINS_LOCATION;
+      bfields[0].location = bloc;
 
       Type* uintptr_type = Type::lookup_integer_type("uintptr");
       bfields[1].name = "__element_count";
       bfields[1].btype = uintptr_type->get_backend(gogo);
-      bfields[1].location = BUILTINS_LOCATION;
+      bfields[1].location = bloc;
 
       bfields[2].name = "__bucket_count";
       bfields[2].btype = bfields[1].btype;
-      bfields[2].location = BUILTINS_LOCATION;
+      bfields[2].location = bloc;
 
       Btype* bvt = gogo->backend()->void_type();
       Btype* bpvt = gogo->backend()->pointer_type(bvt);
       Btype* bppvt = gogo->backend()->pointer_type(bpvt);
       bfields[3].name = "__buckets";
       bfields[3].btype = bppvt;
-      bfields[3].location = BUILTINS_LOCATION;
+      bfields[3].location = bloc;
 
       Btype *bt = gogo->backend()->struct_type(bfields);
-      bt = gogo->backend()->named_type("__go_map", bt, BUILTINS_LOCATION);
+      bt = gogo->backend()->named_type("__go_map", bt, bloc);
       backend_map_type = gogo->backend()->pointer_type(bt);
     }
   return backend_map_type;
@@ -4828,7 +5738,7 @@ Map_type::make_map_type_descriptor_type()
 Expression*
 Map_type::do_type_descriptor(Gogo* gogo, Named_type* name)
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   Type* mtdt = Map_type::make_map_type_descriptor_type();
 
@@ -4864,13 +5774,13 @@ Map_type::Map_descriptors Map_type::map_descriptors;
 // Build a map descriptor for this type.  Return a pointer to it.
 
 tree
-Map_type::map_descriptor_pointer(Gogo* gogo, source_location location)
+Map_type::map_descriptor_pointer(Gogo* gogo, Location location)
 {
   Bvariable* bvar = this->map_descriptor(gogo);
   tree var_tree = var_to_tree(bvar);
   if (var_tree == error_mark_node)
     return error_mark_node;
-  return build_fold_addr_expr_loc(location, var_tree);
+  return build_fold_addr_expr_loc(location.gcc_location(), var_tree);
 }
 
 // Build a map descriptor for this type.
@@ -4907,7 +5817,7 @@ Map_type::map_descriptor(Gogo* gogo)
   Expression_list* vals = new Expression_list();
   vals->reserve(4);
 
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   Struct_field_list::const_iterator p = fields->begin();
 
@@ -4987,7 +5897,7 @@ Map_type::do_reflection(Gogo* gogo, std::string* ret) const
 {
   ret->append("map[");
   this->append_reflection(this->key_type_, gogo, ret);
-  ret->append("] ");
+  ret->append("]");
   this->append_reflection(this->val_type_, gogo, ret);
 }
 
@@ -5028,7 +5938,7 @@ Map_type::do_import(Import* imp)
 // Make a map type.
 
 Map_type*
-Type::make_map_type(Type* key_type, Type* val_type, source_location location)
+Type::make_map_type(Type* key_type, Type* val_type, Location location)
 {
   return new Map_type(key_type, val_type, location);
 }
@@ -5075,7 +5985,8 @@ Channel_type::do_get_backend(Gogo* gogo)
     {
       std::vector<Backend::Btyped_identifier> bfields;
       Btype* bt = gogo->backend()->struct_type(bfields);
-      bt = gogo->backend()->named_type("__go_channel", bt, BUILTINS_LOCATION);
+      bt = gogo->backend()->named_type("__go_channel", bt,
+                                       Linemap::predeclared_location());
       backend_channel_type = gogo->backend()->pointer_type(bt);
     }
   return backend_channel_type;
@@ -5111,7 +6022,7 @@ Channel_type::make_chan_type_descriptor_type()
 Expression*
 Channel_type::do_type_descriptor(Gogo* gogo, Named_type* name)
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   Type* ctdt = Channel_type::make_chan_type_descriptor_type();
 
@@ -5670,15 +6581,17 @@ Interface_type::get_backend_empty_interface_type(Gogo* gogo)
     {
       std::vector<Backend::Btyped_identifier> bfields(2);
 
+      Location bloc = Linemap::predeclared_location();
+
       Type* pdt = Type::make_type_descriptor_ptr_type();
       bfields[0].name = "__type_descriptor";
       bfields[0].btype = pdt->get_backend(gogo);
-      bfields[0].location = UNKNOWN_LOCATION;
+      bfields[0].location = bloc;
 
       Type* vt = Type::make_pointer_type(Type::make_void_type());
       bfields[1].name = "__object";
       bfields[1].btype = vt->get_backend(gogo);
-      bfields[1].location = UNKNOWN_LOCATION;
+      bfields[1].location = bloc;
 
       empty_interface_type = gogo->backend()->struct_type(bfields);
     }
@@ -5693,7 +6606,7 @@ static void
 get_backend_interface_fields(Gogo* gogo, Interface_type* type,
                             std::vector<Backend::Btyped_identifier>* bfields)
 {
-  source_location loc = type->location();
+  Location loc = type->location();
 
   std::vector<Backend::Btyped_identifier> mfields(type->methods()->size() + 1);
 
@@ -5727,7 +6640,7 @@ get_backend_interface_fields(Gogo* gogo, Interface_type* type,
   Type* vt = Type::make_pointer_type(Type::make_void_type());
   (*bfields)[1].name = "__object";
   (*bfields)[1].btype = vt->get_backend(gogo);
-  (*bfields)[1].location = UNKNOWN_LOCATION;
+  (*bfields)[1].location = Linemap::predeclared_location();
 }
 
 // Return a tree for an interface type.  An interface is a pointer to
@@ -5789,7 +6702,7 @@ Interface_type::make_interface_type_descriptor_type()
 Expression*
 Interface_type::do_type_descriptor(Gogo* gogo, Named_type* name)
 {
-  source_location bloc = BUILTINS_LOCATION;
+  Location bloc = Linemap::predeclared_location();
 
   Type* itdt = Interface_type::make_interface_type_descriptor_type();
 
@@ -5800,9 +6713,9 @@ Interface_type::do_type_descriptor(Gogo* gogo, Named_type* name)
 
   Struct_field_list::const_iterator pif = ifields->begin();
   go_assert(pif->is_field_name("commonType"));
-  ivals->push_back(this->type_descriptor_constructor(gogo,
-                                                    RUNTIME_TYPE_KIND_INTERFACE,
-                                                    name, NULL, true));
+  const int rt = RUNTIME_TYPE_KIND_INTERFACE;
+  ivals->push_back(this->type_descriptor_constructor(gogo, rt, name, NULL,
+                                                    true));
 
   ++pif;
   go_assert(pif->is_field_name("methods"));
@@ -5869,13 +6782,13 @@ Interface_type::do_reflection(Gogo* gogo, std::string* ret) const
   ret->append("interface {");
   if (this->methods_ != NULL)
     {
+      ret->push_back(' ');
       for (Typed_identifier_list::const_iterator p = this->methods_->begin();
           p != this->methods_->end();
           ++p)
        {
          if (p != this->methods_->begin())
-           ret->append(";");
-         ret->push_back(' ');
+           ret->append("; ");
          if (!Gogo::is_hidden_name(p->name()))
            ret->append(p->name());
          else
@@ -5891,8 +6804,9 @@ Interface_type::do_reflection(Gogo* gogo, std::string* ret) const
          sub = sub.substr(4);
          ret->append(sub);
        }
+      ret->push_back(' ');
     }
-  ret->append(" }");
+  ret->append("}");
 }
 
 // Mangled name.
@@ -6095,7 +7009,7 @@ Interface_type::do_import(Import* imp)
 
 Interface_type*
 Type::make_interface_type(Typed_identifier_list* methods,
-                         source_location location)
+                         Location location)
 {
   return new Interface_type(methods, location);
 }
@@ -6105,7 +7019,7 @@ Type::make_interface_type(Typed_identifier_list* methods,
 // Bind a method to an object.
 
 Expression*
-Method::bind_method(Expression* expr, source_location location) const
+Method::bind_method(Expression* expr, Location location) const
 {
   if (this->stub_ == NULL)
     {
@@ -6144,7 +7058,7 @@ Named_method::do_type() const
 
 // Return the location of the method receiver.
 
-source_location
+Location
 Named_method::do_receiver_location() const
 {
   return this->do_type()->receiver()->location();
@@ -6153,7 +7067,7 @@ Named_method::do_receiver_location() const
 // Bind a method to an object.
 
 Expression*
-Named_method::do_bind_method(Expression* expr, source_location location) const
+Named_method::do_bind_method(Expression* expr, Location location) const
 {
   Named_object* no = this->named_object_;
   Bound_method_expression* bme = Expression::make_bound_method(expr, no,
@@ -6177,7 +7091,7 @@ Named_method::do_bind_method(Expression* expr, source_location location) const
 
 Expression*
 Interface_method::do_bind_method(Expression* expr,
-                                source_location location) const
+                                Location location) const
 {
   return Expression::make_interface_field_reference(expr, this->name_,
                                                    location);
@@ -6284,6 +7198,21 @@ Named_type::is_named_error_type() const
   return ret;
 }
 
+// Whether this type is comparable.  We have to be careful about
+// circular type definitions.
+
+bool
+Named_type::named_type_is_comparable(std::string* reason) const
+{
+  if (this->seen_)
+    return false;
+  this->seen_ = true;
+  bool ret = Type::are_compatible_for_comparison(true, this->type_,
+                                                this->type_, reason);
+  this->seen_ = false;
+  return ret;
+}
+
 // Add a method to this type.
 
 Named_object*
@@ -6299,7 +7228,7 @@ Named_type::add_method(const std::string& name, Function* function)
 Named_object*
 Named_type::add_method_declaration(const std::string& name, Package* package,
                                   Function_type* type,
-                                  source_location location)
+                                  Location location)
 {
   if (this->local_methods_ == NULL)
     this->local_methods_ = new Bindings(NULL);
@@ -6608,6 +7537,22 @@ Named_type::do_has_pointer() const
   return ret;
 }
 
+// Return whether comparisons for this type can use the identity
+// function.
+
+bool
+Named_type::do_compare_is_identity(Gogo* gogo) const
+{
+  // We don't use this->seen_ here because compare_is_identity may
+  // call base() later, and that will mess up if seen_ is set here.
+  if (this->seen_in_compare_is_identity_)
+    return false;
+  this->seen_in_compare_is_identity_ = true;
+  bool ret = this->type_->compare_is_identity(gogo);
+  this->seen_in_compare_is_identity_ = false;
+  return ret;
+}
+
 // Return a hash code.  This is used for method lookup.  We simply
 // hash on the name itself.
 
@@ -6725,6 +7670,7 @@ Named_type::convert(Gogo* gogo)
 
   this->named_btype_ = bt;
   this->is_converted_ = true;
+  this->is_placeholder_ = false;
 }
 
 // Create the placeholder for a named type.  This is the first step in
@@ -6785,6 +7731,7 @@ Named_type::create_placeholder(Gogo* gogo)
     case TYPE_STRUCT:
       bt = gogo->backend()->placeholder_struct_type(this->name(),
                                                    this->location_);
+      this->is_placeholder_ = true;
       set_name = false;
       break;
 
@@ -6793,8 +7740,11 @@ Named_type::create_placeholder(Gogo* gogo)
        bt = gogo->backend()->placeholder_struct_type(this->name(),
                                                      this->location_);
       else
-       bt = gogo->backend()->placeholder_array_type(this->name(),
-                                                    this->location_);
+       {
+         bt = gogo->backend()->placeholder_array_type(this->name(),
+                                                      this->location_);
+         this->is_placeholder_ = true;
+       }
       set_name = false;
       break;
 
@@ -6967,7 +7917,7 @@ Named_type::do_type_descriptor(Gogo* gogo, Named_type* name)
 void
 Named_type::do_reflection(Gogo* gogo, std::string* ret) const
 {
-  if (this->location() != BUILTINS_LOCATION)
+  if (!Linemap::is_predeclared_location(this->location()))
     {
       const Package* package = this->named_object_->package();
       if (package != NULL)
@@ -6991,7 +7941,7 @@ Named_type::do_mangled_name(Gogo* gogo, std::string* ret) const
 {
   Named_object* no = this->named_object_;
   std::string name;
-  if (this->location() == BUILTINS_LOCATION)
+  if (Linemap::is_predeclared_location(this->location()))
     go_assert(this->in_function_ == NULL);
   else
     {
@@ -7081,7 +8031,7 @@ Named_type::do_export(Export* exp) const
 
 Named_type*
 Type::make_named_type(Named_object* named_object, Type* type,
-                     source_location location)
+                     Location location)
 {
   return new Named_type(named_object, type, location);
 }
@@ -7091,7 +8041,7 @@ Type::make_named_type(Named_object* named_object, Type* type,
 // all required stubs.
 
 void
-Type::finalize_methods(Gogo* gogo, const Type* type, source_location location,
+Type::finalize_methods(Gogo* gogo, const Type* type, Location location,
                       Methods** all_methods)
 {
   *all_methods = NULL;
@@ -7291,7 +8241,7 @@ Type::add_interface_methods_for_type(const Type* type,
 
 void
 Type::build_stub_methods(Gogo* gogo, const Type* type, const Methods* methods,
-                        source_location location)
+                        Location location)
 {
   if (methods == NULL)
     return;
@@ -7317,7 +8267,7 @@ Type::build_stub_methods(Gogo* gogo, const Type* type, const Methods* methods,
       Type* receiver_type = const_cast<Type*>(type);
       if (!m->is_value_method())
        receiver_type = Type::make_pointer_type(receiver_type);
-      source_location receiver_location = m->receiver_location();
+      Location receiver_location = m->receiver_location();
       Typed_identifier* receiver = new Typed_identifier(buf, receiver_type,
                                                        receiver_location);
 
@@ -7397,7 +8347,7 @@ Type::build_one_stub_method(Gogo* gogo, Method* method,
                            const char* receiver_name,
                            const Typed_identifier_list* params,
                            bool is_varargs,
-                           source_location location)
+                           Location location)
 {
   Named_object* receiver_object = gogo->lookup(receiver_name, NULL);
   go_assert(receiver_object != NULL);
@@ -7460,7 +8410,7 @@ Type::build_one_stub_method(Gogo* gogo, Method* method,
 Expression*
 Type::apply_field_indexes(Expression* expr,
                          const Method::Field_indexes* field_indexes,
-                         source_location location)
+                         Location location)
 {
   if (field_indexes == NULL)
     return expr;
@@ -7526,7 +8476,7 @@ Type::method_function(const Methods* methods, const std::string& name,
 Expression*
 Type::bind_field_or_method(Gogo* gogo, const Type* type, Expression* expr,
                           const std::string& name,
-                          source_location location)
+                          Location location)
 {
   if (type->deref()->is_error_type())
     return Expression::make_error(location);
@@ -8040,7 +8990,7 @@ Forward_declaration_type::add_method(const std::string& name,
 Named_object*
 Forward_declaration_type::add_method_declaration(const std::string& name,
                                                 Function_type* type,
-                                                source_location location)
+                                                Location location)
 {
   Named_object* no = this->named_object();
   if (no->is_unknown())
@@ -8085,15 +9035,16 @@ Forward_declaration_type::do_get_backend(Gogo* gogo)
 Expression*
 Forward_declaration_type::do_type_descriptor(Gogo* gogo, Named_type* name)
 {
+  Location ploc = Linemap::predeclared_location();
   if (!this->is_defined())
-    return Expression::make_nil(BUILTINS_LOCATION);
+    return Expression::make_nil(ploc);
   else
     {
       Type* t = this->real_type();
       if (name != NULL)
        return this->named_type_descriptor(gogo, t, name);
       else
-       return Expression::make_type_descriptor(t, BUILTINS_LOCATION);
+       return Expression::make_type_descriptor(t, ploc);
     }
 }