This patch from Chris Manghane uses the backend interface for references to struct fields. Bootstrapped and ran Go testsuite on x86_64-unknown-linux-gnu. Committed to mainline.
Ian 2013-12-16 Chris Manghane <cm...@google.com> * go-gcc.cc (Gcc_backend::struct_field_expression): New function.
Index: gcc/go/gofrontend/expressions.cc =================================================================== --- gcc/go/gofrontend/expressions.cc (revision 205955) +++ gcc/go/gofrontend/expressions.cc (working copy) @@ -11539,28 +11539,12 @@ Field_reference_expression::do_check_typ tree Field_reference_expression::do_get_tree(Translate_context* context) { - tree struct_tree = this->expr_->get_tree(context); - if (struct_tree == error_mark_node - || TREE_TYPE(struct_tree) == error_mark_node) - return error_mark_node; - go_assert(TREE_CODE(TREE_TYPE(struct_tree)) == RECORD_TYPE); - tree field = TYPE_FIELDS(TREE_TYPE(struct_tree)); - if (field == NULL_TREE) - { - // This can happen for a type which refers to itself indirectly - // and then turns out to be erroneous. - go_assert(saw_errors()); - return error_mark_node; - } - for (unsigned int i = this->field_index_; i > 0; --i) - { - field = DECL_CHAIN(field); - go_assert(field != NULL_TREE); - } - if (TREE_TYPE(field) == error_mark_node) - return error_mark_node; - return build3(COMPONENT_REF, TREE_TYPE(field), struct_tree, field, - NULL_TREE); + Bexpression* bstruct = tree_to_expr(this->expr_->get_tree(context)); + Bexpression* ret = + context->gogo()->backend()->struct_field_expression(bstruct, + this->field_index_, + this->location()); + return expr_to_tree(ret); } // Dump ast representation for a field reference expression. Index: gcc/go/gofrontend/backend.h =================================================================== --- gcc/go/gofrontend/backend.h (revision 205955) +++ gcc/go/gofrontend/backend.h (working copy) @@ -280,6 +280,10 @@ class Backend virtual Bexpression* address_expression(Bexpression*, Location) = 0; + // Return an expression for the field at INDEX in BSTRUCT. + virtual Bexpression* + struct_field_expression(Bexpression* bstruct, size_t index, Location) = 0; + // Statements. // Create an error statement. This is used for cases which should Index: gcc/go/go-gcc.cc =================================================================== --- gcc/go/go-gcc.cc (revision 205955) +++ gcc/go/go-gcc.cc (working copy) @@ -243,6 +243,9 @@ class Gcc_backend : public Backend Bexpression* address_expression(Bexpression*, Location); + Bexpression* + struct_field_expression(Bexpression*, size_t, Location); + // Statements. Bstatement* @@ -998,6 +1001,39 @@ Gcc_backend::address_expression(Bexpress return this->make_expression(ret); } +// Return an expression for the field at INDEX in BSTRUCT. + +Bexpression* +Gcc_backend::struct_field_expression(Bexpression* bstruct, size_t index, + Location location) +{ + tree struct_tree = bstruct->get_tree(); + if (struct_tree == error_mark_node + || TREE_TYPE(struct_tree) == error_mark_node) + return this->error_expression(); + gcc_assert(TREE_CODE(TREE_TYPE(struct_tree)) == RECORD_TYPE); + tree field = TYPE_FIELDS(TREE_TYPE(struct_tree)); + if (field == NULL_TREE) + { + // This can happen for a type which refers to itself indirectly + // and then turns out to be erroneous. + return this->error_expression(); + } + for (unsigned int i = index; i > 0; --i) + { + field = DECL_CHAIN(field); + gcc_assert(field != NULL_TREE); + } + if (TREE_TYPE(field) == error_mark_node) + return this->error_expression(); + tree ret = fold_build3_loc(location.gcc_location(), COMPONENT_REF, + TREE_TYPE(field), struct_tree, field, + NULL_TREE); + if (TREE_CONSTANT(struct_tree)) + TREE_CONSTANT(ret) = 1; + return tree_to_expr(ret); +} + // An expression as a statement. Bstatement* Index: gcc/go/ChangeLog =================================================================== --- gcc/go/ChangeLog (revision 205955) +++ gcc/go/ChangeLog (working copy) @@ -1,3 +1,7 @@ +2013-12-16 Chris Manghane <cm...@google.com> + + * go-gcc.cc (Gcc_backend::struct_field_expression): New function. + 2013-12-11 Ian Lance Taylor <i...@google.com> * go-lang.c (go_langhook_post_options): Disable sibling calls by