[Ada] Add support for subprogram renamings

Consider the following declaration:

    function Foo (I : Integer) return Integer renames Pack.Bar;

As Foo is not materialized as a routine whose name is derived from Foo,
GDB currently cannot use it:

    (gdb) print foo(0)
    No definition of "foo" in current context.

However, compilers can emit DW_TAG_imported_declaration in order to
materialize the fact that Foo is actually another name for Pack.Bar.
This commit enhances the DWARF reader to record global renamings (it
used to put global ones in a static block) and enhances the Ada engine
to leverage this information during symbol lookup.

gdb/ChangeLog:

	* ada-lang.c: Include namespace.h
	(aux_add_nonlocal_symbols): Fix a function name in comment.
	(ada_add_block_renamings): New.
	(add_nonlocal_symbols): Add global renamings handling.
	(ada_lookup_symbol_list_worker): Move the symbol lookup part
	to...
	(ada_add_all_symbols): ... this new function.
	(ada_add_block_symbols): Try to match the input name against the
	"using directives list", perform a recursive symbol lookup on
	the matched declarations.
	* block.h (struct block): Move the_namespace to top-level as
	namespace_info. Remove the language_specific field.
	(BLOCK_NAMESPACE): Update access to the namespace_info field.
	* buildsym.h (using_directives): Rename into...
	(local_using_directives): ... this.
	(global_using_directives): New.
	(struct context_stack): Rename the using_directives field into
	local_using_directives.
	* buildsym.c (finish_block_internal): Deal with the proper
	using directives repository (local or global).
	(prepare_for_building): Reset local_using_directives. Assert
	that there is no pending global using directive.
	(reset_symtab_globals): Reset global_using_directives and
	local_using_directives.
	(end_symtab_get_static_block): Don't ignore symtabs that have
	only using directives.
	(push_context): Update references to local_using_directives.
	(buildsym_init): Do not reset using_directives.
	* cp-support.c: Include namespace.h.
	* cp-support.h (struct using_direct): Move to namespace.h.
	(cp_add_using_directives): Move to namespace.h.
	* cp-namespace.c: Include namespace.h
	(cp_add_using_directive): Move to namespace.c, rename it to
	add_using_directive, add a "using_directives" argument and use
	it as the pending using directives repository.  All callers
	updated.
	* dwarf2read.c (using_directives): New.
	(read_import_statement): Call using_directives.
	(read_func_scope): Update references to local_using_directives.
	(read_lexical_block_scope): Likewise.
	(read_namespace): Update the heading comment, call
	using_directives.
	* namespace.h: New file.
	* namespace.c: New file.
	* Makefile.in (SFILES): Add namespace.c.
	(COMMON_OBS): Add namespace.o

gdb/testsuite/ChangeLog:

	* gdb.ada/fun_renaming.exp: New testcase.
	* gdb.ada/fun_renaming/fun_renaming.adb: New file.
	* gdb.ada/fun_renaming/pack.adb: New file.
	* gdb.ada/fun_renaming/pack.ads: New file.

Tested on x86_64-linux.  Support for this in GCC is in the pipeline: see
<https://gcc.gnu.org/ml/gcc-patches/2015-07/msg02166.html>.

1 files changed, 1 insertions, 91 deletions

diff --git a/gdb/cp-support.h b/gdb/cp-support.h
index f9aac3f..12d8d80 100644
--- a/gdb/cp-support.h
+++ b/gdb/cp-support.h
@@ -36,6 +36,7 @@ struct block;
 struct objfile;
 struct type;
 struct demangle_component;
+struct using_direct;
 
 /* A string representing the name of the anonymous namespace used in GDB.  */
 
@@ -59,89 +60,6 @@ struct demangle_parse_info
   struct obstack obstack;
 };
 
-/* This struct is designed to store data from using directives.  It
-   says that names from namespace IMPORT_SRC should be visible within
-   namespace IMPORT_DEST.  These form a linked list; NEXT is the next
-   element of the list.  If the imported namespace or declaration has
-   been aliased within the IMPORT_DEST namespace, ALIAS is set to a
-   string representing the alias.  Otherwise, ALIAS is NULL.
-   DECLARATION is the name of the imported declaration, if this import
-   statement represents one.  Otherwise DECLARATION is NULL and this
-   import statement represents a namespace.
-
-   C++:      using namespace A;
-   Fortran:  use A
-   import_src = "A"
-   import_dest = local scope of the import statement even such as ""
-   alias = NULL
-   declaration = NULL
-   excludes = NULL
-
-   C++:      using A::x;
-   Fortran:  use A, only: x
-   import_src = "A"
-   import_dest = local scope of the import statement even such as ""
-   alias = NULL
-   declaration = "x"
-   excludes = NULL
-   The declaration will get imported as import_dest::x.
-
-   C++ has no way to import all names except those listed ones.
-   Fortran:  use A, localname => x
-   import_src = "A"
-   import_dest = local scope of the import statement even such as ""
-   alias = "localname"
-   declaration = "x"
-   excludes = NULL
-   +
-   import_src = "A"
-   import_dest = local scope of the import statement even such as ""
-   alias = NULL
-   declaration = NULL
-   excludes = ["x"]
-   All the entries of A get imported except of "x".  "x" gets imported as
-   "localname".  "x" is not defined as a local name by this statement.
-
-   C++:      namespace LOCALNS = A;
-   Fortran has no way to address non-local namespace/module.
-   import_src = "A"
-   import_dest = local scope of the import statement even such as ""
-   alias = "LOCALNS"
-   declaration = NULL
-   excludes = NULL
-   The namespace will get imported as the import_dest::LOCALNS
-   namespace.
-
-   C++ cannot express it, it would be something like: using localname
-   = A::x;
-   Fortran:  use A, only localname => x
-   import_src = "A"
-   import_dest = local scope of the import statement even such as ""
-   alias = "localname"
-   declaration = "x"
-   excludes = NULL
-   The declaration will get imported as localname or
-   `import_dest`localname.  */
-
-struct using_direct
-{
-  const char *import_src;
-  const char *import_dest;
-
-  const char *alias;
-  const char *declaration;
-
-  struct using_direct *next;
-
-  /* Used during import search to temporarily mark this node as
-     searched.  */
-  int searched;
-
-  /* USING_DIRECT has variable allocation size according to the number of
-     EXCLUDES entries, the last entry is NULL.  */
-  const char *excludes[1];
-};
-
 
 /* Functions from cp-support.c.  */
 
@@ -181,14 +99,6 @@ extern struct type *cp_lookup_rtti_type (const char *name,
 
 extern int cp_is_in_anonymous (const char *symbol_name);
 
-extern void cp_add_using_directive (const char *dest,
-                                    const char *src,
-                                    const char *alias,
-				    const char *declaration,
-				    VEC (const_char_ptr) *excludes,
-				    int copy_names,
-                                    struct obstack *obstack);
-
 extern void cp_scan_for_anonymous_namespaces (const struct symbol *symbol,
 					      struct objfile *objfile);