This patch to the gcc-specific part of the Go frontend tweaks the debug
info in a couple of ways.
For a named struct or array type, this uses build_distinct_type_copy
rather than build_variant_type_copy. Using build_variant_type_copy
caused trouble because it wound up causing the main variant to be named
while the copy was unnamed. The effect was to cause gcc to emit a
typedef defined as itself, which was not useful.
The middle-end currently expects all basic types to have a name. If
they don't, it uses the name __unknown__, which is not helpful (see
modified_type_die in dwarf2out.c). In Go all basic types will have a
name anyhow. This patch ensures that the first time we see a named
builtin basic type, we use that name rather than making a copy.
Bootstrapped and ran Go testsuite on x86_64-unknown-linux-gnu.
Committed to mainline.
Ian
2011-12-27 Ian Lance Taylor <i...@google.com>
* go-gcc.cc (Gcc_backend::set_placeholder_struct_type): Use
build_distinct_type_copy rather than build_variant_type_copy.
(Gcc_backend::set_placeholder_array_type): Likewise.
(Gcc_backend::named_type): Add special handling for builtin
basic types.
Index: go-gcc.cc
===================================================================
--- go-gcc.cc (revision 182696)
+++ go-gcc.cc (working copy)
@@ -663,7 +663,7 @@ Gcc_backend::set_placeholder_struct_type
Btype* r = this->fill_in_struct(placeholder, fields);
// Build the data structure gcc wants to see for a typedef.
- tree copy = build_variant_type_copy(t);
+ tree copy = build_distinct_type_copy(t);
TYPE_NAME(copy) = NULL_TREE;
DECL_ORIGINAL_TYPE(TYPE_NAME(t)) = copy;
@@ -696,7 +696,7 @@ Gcc_backend::set_placeholder_array_type(
Btype* r = this->fill_in_array(placeholder, element_btype, length);
// Build the data structure gcc wants to see for a typedef.
- tree copy = build_variant_type_copy(t);
+ tree copy = build_distinct_type_copy(t);
TYPE_NAME(copy) = NULL_TREE;
DECL_ORIGINAL_TYPE(TYPE_NAME(t)) = copy;
@@ -712,6 +712,24 @@ Gcc_backend::named_type(const std::strin
tree type = btype->get_tree();
if (type == error_mark_node)
return this->error_type();
+
+ // The middle-end expects a basic type to have a name. In Go every
+ // basic type will have a name. The first time we see a basic type,
+ // give it whatever Go name we have at this point.
+ if (TYPE_NAME(type) == NULL_TREE
+ && location.gcc_location() == BUILTINS_LOCATION
+ && (TREE_CODE(type) == INTEGER_TYPE
+ || TREE_CODE(type) == REAL_TYPE
+ || TREE_CODE(type) == COMPLEX_TYPE
+ || TREE_CODE(type) == BOOLEAN_TYPE))
+ {
+ tree decl = build_decl(BUILTINS_LOCATION, TYPE_DECL,
+ get_identifier_from_string(name),
+ type);
+ TYPE_NAME(type) = decl;
+ return this->make_type(type);
+ }
+
tree copy = build_variant_type_copy(type);
tree decl = build_decl(location.gcc_location(), TYPE_DECL,
get_identifier_from_string(name),
