On Mon, May 29, 2017 at 9:50 AM, Pierre-Marie de Rodat
<dero...@adacore.com> wrote:
> Hello,
>
> The DWARF back-end used to systematically ignore file-scope function and
> variable declarations. While this is justified in language like C/C++,
> where such declarations can appear in several translation units and thus
> bloat uselessly the debug info, this behavior is counter-productive in
> languages with a well-defined module system. Specifically, it prevents
> the description of imported entities, that belong to foreign languages,
> making them unavailable from debuggers.
>
> Take for instance:
>
> package C_Binding is
> function My_C_Function (I : Integer) return Integer;
> pragma Import (C, My_C_Function, "my_c_function");
> end C_Binding;
>
> This makes available for Ada programs the C function "my_c_function"
> under the following name: C_Binding.My_C_Function. When GCC compiles
> it, though, it is represented as a FUNCTION_DECL node with DECL_EXTERNAL
> set and a null DECL_INITIAL, which used to be discarded unconditionally
> in the DWARF back-end.
>
> This patch introduces a new DECL language hook:
> emit_debug_info_for_decl_p, which the DWARF back-end uses to determine
> whether it should emit debug info for some declaration. This makes it
> possible for front-ends to decide the appropriate behavior.
>
> This patch also updates the Ada front-end to override this hook, so that
> declarations such as the above do generate debugging information.
>
> Bootstrapped and reg-tested on x86_64-linux. Ok to commit? Thank you in
> advance!
I think the issue is unfortunate in the C frontend as well. So I believe we can
go without a new langhook and instead make sure dwarf2out_early_global_decl
is not called for uninteresting decls (which means eventually pushing the
call(s) of that hook more towards the FEs).
For C/C++ it would be reasonable to output debug info for external declarations
that end up being used for example.
Richard.
> gcc/
> * langhooks.h
> (lang_hooks_for_decls::emit_debug_info_for_decl_p): New field.
> * langhooks-def.h
> (LANG_HOOKS_EMIT_DEBUG_INFO_FOR_DECL_P): New macro.
> * dwarf2out.c (gen_decl_die): Use the new hook to determine
> whether to ignore file-scope declarations.
> (dwarf2out_early_global_decl): Likewise.
> (dwaf2out_decl): Likewise.
>
> gcc/ada
> * gcc-interface/ada-tree.h (DECL_FUNCTION_IS_DEF): New macro.
> * gcc-interface/misc.c (gnat_emit_debug_info_for_decl_p): New
> function.
> (LANG_HOOKS_EMIT_DEBUG_INFO_FOR_DECL_P): Override macro.
> * gcc-interface/trans.c (Compilation_Unit_to_gnu): Tag the
> elaboration procedure as a definition.
> (Subprogram_Body_to_gnu): Tag the subprogram as a definition.
> * gcc-interface/decl.c (gnat_to_gnu_entity): Tag declarations of
> imported subprograms for the current compilation unit as
> definitions. Disable debug info for references to variables.
> * gcc-interface/utils.c (create_subprog_decl): Add a DEFINITION
> parameter. If it is true, tag the function as a definition.
> Update all callers.
> (gnat_pushdecl): Add external DECLs that are not built-in
> functions to their binding scope.
> (gnat_write_global_declarations): Emit debug info for imported
> functions. Filter out external variables for which debug info
> is disabled.
> * gcc-interface/gigi.c (create_subprog_decl): Update
> declaration.
>
> git-svn-id: svn+ssh://svn.us.adacore.com/Dev/trunk/gcc-interfaces@328405
> f8352e7e-cb20-0410-8ce7-b5d9e71c585c
> ---
> gcc/ada/gcc-interface/ada-tree.h | 7 +++++-
> gcc/ada/gcc-interface/decl.c | 19 +++++++++------
> gcc/ada/gcc-interface/gigi.h | 5 +++-
> gcc/ada/gcc-interface/misc.c | 11 +++++++++
> gcc/ada/gcc-interface/trans.c | 52
> ++++++++++++++++++++++++----------------
> gcc/ada/gcc-interface/utils.c | 34 +++++++++++++++++++-------
> gcc/dwarf2out.c | 13 ++++++----
> gcc/langhooks-def.h | 2 ++
> gcc/langhooks.h | 9 +++++++
> 9 files changed, 109 insertions(+), 43 deletions(-)
>
> diff --git a/gcc/ada/gcc-interface/ada-tree.h
> b/gcc/ada/gcc-interface/ada-tree.h
> index a3d38b1b22e..511a0bd8173 100644
> --- a/gcc/ada/gcc-interface/ada-tree.h
> +++ b/gcc/ada/gcc-interface/ada-tree.h
> @@ -6,7 +6,7 @@
> * *
> * C Header File *
> * *
> - * Copyright (C) 1992-2016, Free Software Foundation, Inc. *
> + * Copyright (C) 1992-2017, Free Software Foundation, Inc. *
> * *
> * GNAT is free software; you can redistribute it and/or modify it under *
> * terms of the GNU General Public License as published by the Free Soft- *
> @@ -463,6 +463,11 @@ do { \
> a discriminant of a discriminated type without default expression. */
> #define DECL_INVARIANT_P(NODE) DECL_LANG_FLAG_4 (FIELD_DECL_CHECK (NODE))
>
> +/* Nonzero in a FUNCTION_DECL if this is a definition, i.e. if it was created
> + by a call to gnat_to_gnu_entity with definition set to True. */
> +#define DECL_FUNCTION_IS_DEF(NODE) \
> + DECL_LANG_FLAG_4 (FUNCTION_DECL_CHECK (NODE))
> +
> /* Nonzero in a VAR_DECL if it is a temporary created to hold the return
> value of a function call or 'reference to a function call. */
> #define DECL_RETURN_VALUE_P(NODE) DECL_LANG_FLAG_5 (VAR_DECL_CHECK (NODE))
> diff --git a/gcc/ada/gcc-interface/decl.c b/gcc/ada/gcc-interface/decl.c
> index eab244e910c..83b9d0749fe 100644
> --- a/gcc/ada/gcc-interface/decl.c
> +++ b/gcc/ada/gcc-interface/decl.c
> @@ -1392,7 +1392,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree
> gnu_expr, bool definition)
> = create_var_decl (create_concat_name (gnat_entity, "ALIGN"),
> NULL_TREE, gnu_new_type, NULL_TREE,
> false, false, false, false, false,
> - true, debug_info_p, NULL, gnat_entity);
> + true, debug_info_p && definition, NULL,
> + gnat_entity);
>
> /* Initialize the aligned field if we have an initializer. */
> if (gnu_expr)
> @@ -1441,7 +1442,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree
> gnu_expr, bool definition)
> NULL_TREE, gnu_type, gnu_expr,
> const_flag, Is_Public (gnat_entity),
> imported_p || !definition, static_flag,
> - volatile_flag, true, debug_info_p,
> + volatile_flag, true,
> + debug_info_p && definition,
> NULL, gnat_entity);
> gnu_expr = build_unary_op (ADDR_EXPR, NULL_TREE, gnu_unc_var);
> TREE_CONSTANT (gnu_expr) = 1;
> @@ -1492,8 +1494,9 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree
> gnu_expr, bool definition)
> = create_var_decl (gnu_entity_name, gnu_ext_name, gnu_type,
> gnu_expr, const_flag, Is_Public (gnat_entity),
> imported_p || !definition, static_flag,
> - volatile_flag, artificial_p, debug_info_p,
> - attr_list, gnat_entity, !renamed_obj);
> + volatile_flag, artificial_p,
> + debug_info_p && definition, attr_list,
> + gnat_entity, !renamed_obj);
> DECL_BY_REF_P (gnu_decl) = used_by_ref;
> DECL_POINTS_TO_READONLY_P (gnu_decl) = used_by_ref &&
> inner_const_flag;
> DECL_CAN_NEVER_BE_NULL_P (gnu_decl) = Can_Never_Be_Null (gnat_entity);
> @@ -1545,8 +1548,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree
> gnu_expr, bool definition)
> = create_var_decl (gnu_entity_name, gnu_ext_name, gnu_type,
> gnu_expr, true, Is_Public (gnat_entity),
> !definition, static_flag, volatile_flag,
> - artificial_p, debug_info_p, attr_list,
> - gnat_entity, false);
> + artificial_p, debug_info_p && definition,
> + attr_list, gnat_entity, false);
>
> SET_DECL_CONST_CORRESPONDING_VAR (gnu_decl, gnu_corr_var);
> }
> @@ -4083,7 +4086,9 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree
> gnu_expr, bool definition)
> gnu_type, gnu_param_list,
> inline_status, public_flag,
> extern_flag, artificial_p,
> - debug_info_p, attr_list,
> gnat_entity);
> + debug_info_p,
> + definition && imported_p, attr_list,
> + gnat_entity);
>
> DECL_STUBBED_P (gnu_decl)
> = (Convention (gnat_entity) == Convention_Stubbed);
> diff --git a/gcc/ada/gcc-interface/gigi.h b/gcc/ada/gcc-interface/gigi.h
> index b1fb34ad620..0e25b6129a3 100644
> --- a/gcc/ada/gcc-interface/gigi.h
> +++ b/gcc/ada/gcc-interface/gigi.h
> @@ -720,6 +720,8 @@ extern tree create_label_decl (tree name, Node_Id
> gnat_node);
>
> DEBUG_INFO_P is true if we need to write debug information for it.
>
> + DEFINITION is true if the subprogram is to be considered as a definition.
> +
> ATTR_LIST is the list of attributes to be attached to the subprogram.
>
> GNAT_NODE is used for the position of the decl. */
> @@ -728,7 +730,8 @@ extern tree create_subprog_decl (tree name, tree
> asm_name, tree type,
> enum inline_status_t inline_status,
> bool public_flag, bool extern_flag,
> bool artificial_p, bool debug_info_p,
> - struct attrib *attr_list, Node_Id gnat_node);
> + bool definition, struct attrib *attr_list,
> + Node_Id gnat_node);
>
> /* Given a subprogram declaration DECL, its assembler name and its type,
> finish constructing the subprogram declaration from ASM_NAME and TYPE. */
> diff --git a/gcc/ada/gcc-interface/misc.c b/gcc/ada/gcc-interface/misc.c
> index 18c825ca13e..cd0467ef8d9 100644
> --- a/gcc/ada/gcc-interface/misc.c
> +++ b/gcc/ada/gcc-interface/misc.c
> @@ -1348,6 +1348,15 @@ gnat_eh_personality (void)
> return gnat_eh_personality_decl;
> }
>
> +/* Given DECL, which is a reference (we don't have a definition for it in
> this
> + compilation unit), return whether we should emit debug info for it. */
> +
> +static bool
> +gnat_emit_debug_info_for_decl_p (tree decl)
> +{
> + return TREE_CODE (decl) != FUNCTION_DECL || DECL_FUNCTION_IS_DEF (decl);
> +}
> +
> /* Initialize language-specific bits of tree_contains_struct. */
>
> static void
> @@ -1451,6 +1460,8 @@ get_lang_specific (tree node)
> #define LANG_HOOKS_DEEP_UNSHARING true
> #undef LANG_HOOKS_CUSTOM_FUNCTION_DESCRIPTORS
> #define LANG_HOOKS_CUSTOM_FUNCTION_DESCRIPTORS true
> +#undef LANG_HOOKS_EMIT_DEBUG_INFO_FOR_DECL_P
> +#define LANG_HOOKS_EMIT_DEBUG_INFO_FOR_DECL_P gnat_emit_debug_info_for_decl_p
>
> struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
>
> diff --git a/gcc/ada/gcc-interface/trans.c b/gcc/ada/gcc-interface/trans.c
> index 2542626d0ca..79d099538c9 100644
> --- a/gcc/ada/gcc-interface/trans.c
> +++ b/gcc/ada/gcc-interface/trans.c
> @@ -398,7 +398,7 @@ gigi (Node_Id gnat_root,
> = create_subprog_decl (get_identifier ("__gnat_malloc"), NULL_TREE,
> ftype,
> NULL_TREE, is_disabled, true, true, true, false,
> - NULL, Empty);
> + false, NULL, Empty);
> DECL_IS_MALLOC (malloc_decl) = 1;
>
> ftype = build_function_type_list (void_type_node, ptr_type_node,
> NULL_TREE);
> @@ -406,7 +406,7 @@ gigi (Node_Id gnat_root,
> = create_subprog_decl (get_identifier ("__gnat_free"), NULL_TREE,
> ftype,
> NULL_TREE, is_disabled, true, true, true, false,
> - NULL, Empty);
> + false, NULL, Empty);
>
> ftype = build_function_type_list (ptr_type_node, ptr_type_node, sizetype,
> NULL_TREE);
> @@ -414,7 +414,7 @@ gigi (Node_Id gnat_root,
> = create_subprog_decl (get_identifier ("__gnat_realloc"), NULL_TREE,
> ftype,
> NULL_TREE, is_disabled, true, true, true, false,
> - NULL, Empty);
> + false, NULL, Empty);
>
> /* This is used for 64-bit multiplication with overflow checking. */
> int64_type = gnat_type_for_size (64, 0);
> @@ -423,7 +423,7 @@ gigi (Node_Id gnat_root,
> build_function_type_list (int64_type, int64_type,
> int64_type, NULL_TREE),
> NULL_TREE, is_disabled, true, true, true, false,
> - NULL, Empty);
> + false, NULL, Empty);
>
> /* Name of the _Parent field in tagged record types. */
> parent_name_id = get_identifier (Get_Name_String (Name_uParent));
> @@ -446,21 +446,21 @@ gigi (Node_Id gnat_root,
> = create_subprog_decl
> (get_identifier ("system__soft_links__get_jmpbuf_address_soft"),
> NULL_TREE, build_function_type_list (jmpbuf_ptr_type, NULL_TREE),
> - NULL_TREE, is_disabled, true, true, true, false, NULL, Empty);
> + NULL_TREE, is_disabled, true, true, true, false, false, NULL, Empty);
>
> set_jmpbuf_decl
> = create_subprog_decl
> (get_identifier ("system__soft_links__set_jmpbuf_address_soft"),
> NULL_TREE, build_function_type_list (void_type_node, jmpbuf_ptr_type,
> NULL_TREE),
> - NULL_TREE, is_disabled, true, true, true, false, NULL, Empty);
> + NULL_TREE, is_disabled, true, true, true, false, false, NULL, Empty);
>
> get_excptr_decl
> = create_subprog_decl
> (get_identifier ("system__soft_links__get_gnat_exception"), NULL_TREE,
> build_function_type_list (build_pointer_type (except_type_node),
> NULL_TREE),
> - NULL_TREE, is_disabled, true, true, true, false, NULL, Empty);
> + NULL_TREE, is_disabled, true, true, true, false, false, NULL, Empty);
>
> not_handled_by_others_decl = get_identifier ("not_handled_by_others");
> for (t = TYPE_FIELDS (except_type_node); t; t = DECL_CHAIN (t))
> @@ -478,7 +478,7 @@ gigi (Node_Id gnat_root,
> (get_identifier ("__builtin_setjmp"), NULL_TREE,
> build_function_type_list (integer_type_node, jmpbuf_ptr_type,
> NULL_TREE),
> - NULL_TREE, is_disabled, true, true, true, false, NULL, Empty);
> + NULL_TREE, is_disabled, true, true, true, false, false, NULL, Empty);
> DECL_BUILT_IN_CLASS (setjmp_decl) = BUILT_IN_NORMAL;
> DECL_FUNCTION_CODE (setjmp_decl) = BUILT_IN_SETJMP;
>
> @@ -488,7 +488,7 @@ gigi (Node_Id gnat_root,
> = create_subprog_decl
> (get_identifier ("__builtin_update_setjmp_buf"), NULL_TREE,
> build_function_type_list (void_type_node, jmpbuf_ptr_type, NULL_TREE),
> - NULL_TREE, is_disabled, true, true, true, false, NULL, Empty);
> + NULL_TREE, is_disabled, true, true, true, false, false, NULL, Empty);
> DECL_BUILT_IN_CLASS (update_setjmp_buf_decl) = BUILT_IN_NORMAL;
> DECL_FUNCTION_CODE (update_setjmp_buf_decl) = BUILT_IN_UPDATE_SETJMP_BUF;
>
> @@ -500,14 +500,14 @@ gigi (Node_Id gnat_root,
> raise_nodefer_decl
> = create_subprog_decl
> (get_identifier ("__gnat_raise_nodefer_with_msg"), NULL_TREE, ftype,
> - NULL_TREE, is_disabled, true, true, true, false, NULL, Empty);
> + NULL_TREE, is_disabled, true, true, true, false, false, NULL, Empty);
>
> set_exception_parameter_decl
> = create_subprog_decl
> (get_identifier ("__gnat_set_exception_parameter"), NULL_TREE,
> build_function_type_list (void_type_node, ptr_type_node,
> ptr_type_node,
> NULL_TREE),
> - NULL_TREE, is_disabled, true, true, true, false, NULL, Empty);
> + NULL_TREE, is_disabled, true, true, true, false, false, NULL, Empty);
>
> /* Hooks to call when entering/leaving an exception handler. */
> ftype = build_function_type_list (void_type_node, ptr_type_node,
> NULL_TREE);
> @@ -515,26 +515,30 @@ gigi (Node_Id gnat_root,
> begin_handler_decl
> = create_subprog_decl (get_identifier ("__gnat_begin_handler"),
> NULL_TREE,
> ftype, NULL_TREE,
> - is_disabled, true, true, true, false, NULL, Empty);
> + is_disabled, true, true, true, false, false, NULL,
> + Empty);
> /* __gnat_begin_handler is a dummy procedure. */
> TREE_NOTHROW (begin_handler_decl) = 1;
>
> end_handler_decl
> = create_subprog_decl (get_identifier ("__gnat_end_handler"), NULL_TREE,
> ftype, NULL_TREE,
> - is_disabled, true, true, true, false, NULL, Empty);
> + is_disabled, true, true, true, false, false, NULL,
> + Empty);
>
> unhandled_except_decl
> = create_subprog_decl (get_identifier
> ("__gnat_unhandled_except_handler"),
> NULL_TREE, ftype, NULL_TREE,
> - is_disabled, true, true, true, false, NULL, Empty);
> + is_disabled, true, true, true, false, false, NULL,
> + Empty);
>
> /* Indicate that it never returns. */
> ftype = build_qualified_type (ftype, TYPE_QUAL_VOLATILE);
> reraise_zcx_decl
> = create_subprog_decl (get_identifier ("__gnat_reraise_zcx"), NULL_TREE,
> ftype, NULL_TREE,
> - is_disabled, true, true, true, false, NULL, Empty);
> + is_disabled, true, true, true, false, false, NULL,
> + Empty);
>
> /* Dummy objects to materialize "others" and "all others" in the exception
> tables. These are exported by a-exexpr-gcc.adb, so see this unit for
> @@ -573,7 +577,8 @@ gigi (Node_Id gnat_root,
> tree decl
> = create_subprog_decl
> (get_identifier ("__gnat_last_chance_handler"), NULL_TREE, ftype,
> - NULL_TREE, is_disabled, true, true, true, false, NULL, Empty);
> + NULL_TREE, is_disabled, true, true, true, false, false, NULL,
> + Empty);
> for (i = 0; i < (int) ARRAY_SIZE (gnat_raise_decls); i++)
> gnat_raise_decls[i] = decl;
> }
> @@ -739,7 +744,7 @@ build_raise_check (int check, enum exception_info_kind
> kind)
> result
> = create_subprog_decl (get_identifier (Name_Buffer), NULL_TREE, ftype,
> NULL_TREE, is_disabled, true, true, true, false,
> - NULL, Empty);
> + false, NULL, Empty);
>
> return result;
> }
> @@ -3745,6 +3750,7 @@ Subprogram_Body_to_gnu (Node_Id gnat_node)
> = gnat_to_gnu_entity (gnat_subprog_id, NULL_TREE,
> Acts_As_Spec (gnat_node)
> && !present_gnu_tree (gnat_subprog_id));
> + DECL_FUNCTION_IS_DEF (gnu_subprog_decl) = true;
> gnu_result_decl = DECL_RESULT (gnu_subprog_decl);
> gnu_subprog_type = TREE_TYPE (gnu_subprog_decl);
> gnu_cico_list = TYPE_CI_CO_LIST (gnu_subprog_type);
> @@ -5417,12 +5423,15 @@ Compilation_Unit_to_gnu (Node_Id gnat_node)
> const Entity_Id gnat_unit_entity = Defining_Entity (gnat_unit);
> Entity_Id gnat_entity;
> Node_Id gnat_pragma;
> - /* Make the decl for the elaboration procedure. */
> + /* Make the decl for the elaboration procedure. Emit debug info for it, so
> + that users can break into their elaboration code in debuggers. Kludge:
> + don't consider it as a definition so that we have a line map for its
> body,
> + but no subprogram description in debug info. */
> tree gnu_elab_proc_decl
> = create_subprog_decl
> (create_concat_name (gnat_unit_entity, body_p ? "elabb" : "elabs"),
> NULL_TREE, void_ftype, NULL_TREE,
> - is_disabled, true, false, true, true, NULL, gnat_unit);
> + is_disabled, true, false, true, true, false, NULL, gnat_unit);
> struct elab_info *info;
>
> vec_safe_push (gnu_elab_proc_stack, gnu_elab_proc_decl);
> @@ -6453,7 +6462,7 @@ gnat_to_gnu (Node_Id gnat_node)
> gnu_prefix = gnat_to_gnu (gnat_prefix);
> gnu_prefix = maybe_implicit_deref (gnu_prefix);
> }
> -
> +
> gnu_result
> = build_component_ref (gnu_prefix, gnu_field,
> (Nkind (Parent (gnat_node))
> @@ -6484,7 +6493,8 @@ gnat_to_gnu (Node_Id gnat_node)
> (Entity (Prefix (gnat_node)),
> attr == Attr_Elab_Body ? "elabb" : "elabs"),
> NULL_TREE, void_ftype, NULL_TREE,
> is_disabled,
> - true, true, true, true, NULL, gnat_node);
> + true, true, true, true, false, NULL,
> + gnat_node);
>
> gnu_result = Attribute_to_gnu (gnat_node, &gnu_result_type, attr);
> }
> diff --git a/gcc/ada/gcc-interface/utils.c b/gcc/ada/gcc-interface/utils.c
> index b8c5d3d31f6..af53edcfa3f 100644
> --- a/gcc/ada/gcc-interface/utils.c
> +++ b/gcc/ada/gcc-interface/utils.c
> @@ -763,11 +763,13 @@ gnat_pushdecl (tree decl, Node_Id gnat_node)
> if (!(TREE_CODE (decl) == TYPE_DECL
> && TREE_CODE (TREE_TYPE (decl)) == UNCONSTRAINED_ARRAY_TYPE))
> {
> - if (DECL_EXTERNAL (decl))
> - {
> - if (TREE_CODE (decl) == FUNCTION_DECL && DECL_BUILT_IN (decl))
> - vec_safe_push (builtin_decls, decl);
> - }
> + /* External declarations must go to the binding level they belong to.
> + This will make corresponding imported entities are available in the
> + debugger at the proper time. */
> + if (DECL_EXTERNAL (decl)
> + && TREE_CODE (decl) == FUNCTION_DECL
> + && DECL_BUILT_IN (decl))
> + vec_safe_push (builtin_decls, decl);
> else if (global_bindings_p ())
> vec_safe_push (global_decls, decl);
> else
> @@ -3189,6 +3191,8 @@ create_label_decl (tree name, Node_Id gnat_node)
>
> DEBUG_INFO_P is true if we need to write debug information for it.
>
> + DEFINITION is true if the subprogram is to be considered as a definition.
> +
> ATTR_LIST is the list of attributes to be attached to the subprogram.
>
> GNAT_NODE is used for the position of the decl. */
> @@ -3197,7 +3201,8 @@ tree
> create_subprog_decl (tree name, tree asm_name, tree type, tree
> param_decl_list,
> enum inline_status_t inline_status, bool public_flag,
> bool extern_flag, bool artificial_p, bool debug_info_p,
> - struct attrib *attr_list, Node_Id gnat_node)
> + bool definition, struct attrib *attr_list,
> + Node_Id gnat_node)
> {
> tree subprog_decl = build_decl (input_location, FUNCTION_DECL, name, type);
> DECL_ARGUMENTS (subprog_decl) = param_decl_list;
> @@ -3208,6 +3213,8 @@ create_subprog_decl (tree name, tree asm_name, tree
> type, tree param_decl_list,
>
> if (!debug_info_p)
> DECL_IGNORED_P (subprog_decl) = 1;
> + if (definition)
> + DECL_FUNCTION_IS_DEF (subprog_decl) = 1;
>
> switch (inline_status)
> {
> @@ -5523,10 +5530,21 @@ gnat_write_global_declarations (void)
> if (TREE_CODE (iter) == TYPE_DECL && !DECL_IGNORED_P (iter))
> debug_hooks->type_decl (iter, false);
>
> + /* Output imported functions. */
> + FOR_EACH_VEC_SAFE_ELT (global_decls, i, iter)
> + if (TREE_CODE (iter) == FUNCTION_DECL
> + && DECL_EXTERNAL (iter)
> + && DECL_INITIAL (iter) == NULL
> + && !DECL_IGNORED_P (iter))
> + debug_hooks->early_global_decl (iter);
> +
> /* Then output the global variables. We need to do that after the debug
> - information for global types is emitted so that they are finalized. */
> + information for global types is emitted so that they are finalized.
> Skip
> + external global variables, unless we need to emit debug info for them:
> + this is useful for imported variables, for instance. */
> FOR_EACH_VEC_SAFE_ELT (global_decls, i, iter)
> - if (TREE_CODE (iter) == VAR_DECL)
> + if (TREE_CODE (iter) == VAR_DECL
> + && (!DECL_EXTERNAL (iter) || !DECL_IGNORED_P (iter)))
> rest_of_decl_compilation (iter, true, 0);
>
> /* Output the imported modules/declarations. In GNAT, these are only
> diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
> index 5ff45eb4efd..e2a7f546034 100644
> --- a/gcc/dwarf2out.c
> +++ b/gcc/dwarf2out.c
> @@ -25271,7 +25271,8 @@ gen_decl_die (tree decl, tree origin, struct
> vlr_context *ctx,
> if (DECL_INITIAL (decl_or_origin) == NULL_TREE
> && DECL_FILE_SCOPE_P (decl_or_origin)
> && (current_function_decl == NULL_TREE
> - || DECL_ARTIFICIAL (decl_or_origin)))
> + || DECL_ARTIFICIAL (decl_or_origin))
> + && !lang_hooks.decls.emit_debug_info_for_decl_p (decl_or_origin))
> break;
>
> #if 0
> @@ -25478,9 +25479,10 @@ dwarf2out_early_global_decl (tree decl)
> tree save_fndecl = current_function_decl;
> if (TREE_CODE (decl) == FUNCTION_DECL)
> {
> - /* No cfun means the symbol has no body, so there's nothing
> - to emit. */
> - if (!DECL_STRUCT_FUNCTION (decl))
> + /* Unless we are asked to emit debug info for declarations, no cfun
> + means the symbol has no body, so there's nothing to emit. */
> + if (!DECL_STRUCT_FUNCTION (decl)
> + && !lang_hooks.decls.emit_debug_info_for_decl_p (decl))
> goto early_decl_exit;
>
> /* For nested functions, make sure we have DIEs for the parents
> first
> @@ -25770,7 +25772,8 @@ dwarf2out_decl (tree decl)
> where the inlined function is output in a different LTRANS unit
> or not at all. */
> if (DECL_INITIAL (decl) == NULL_TREE
> - && ! DECL_ABSTRACT_P (decl))
> + && ! DECL_ABSTRACT_P (decl)
> + && ! lang_hooks.decls.emit_debug_info_for_decl_p (decl))
> return;
>
> /* If we're a nested function, initially use a parent of NULL; if we're
> diff --git a/gcc/langhooks-def.h b/gcc/langhooks-def.h
> index ea2006ccec5..e210e9e61ca 100644
> --- a/gcc/langhooks-def.h
> +++ b/gcc/langhooks-def.h
> @@ -225,6 +225,7 @@ extern tree lhd_unit_size_without_reusable_padding (tree);
>
> /* Declaration hooks. */
> #define LANG_HOOKS_GLOBAL_BINDINGS_P global_bindings_p
> +#define LANG_HOOKS_EMIT_DEBUG_INFO_FOR_DECL_P hook_bool_tree_false
> #define LANG_HOOKS_PUSHDECL pushdecl
> #define LANG_HOOKS_GETDECLS getdecls
> #define LANG_HOOKS_DECL_DWARF_ATTRIBUTE lhd_decl_dwarf_attribute
> @@ -247,6 +248,7 @@ extern tree lhd_unit_size_without_reusable_padding (tree);
>
> #define LANG_HOOKS_DECLS { \
> LANG_HOOKS_GLOBAL_BINDINGS_P, \
> + LANG_HOOKS_EMIT_DEBUG_INFO_FOR_DECL_P, \
> LANG_HOOKS_PUSHDECL, \
> LANG_HOOKS_GETDECLS, \
> LANG_HOOKS_DECL_DWARF_ATTRIBUTE, \
> diff --git a/gcc/langhooks.h b/gcc/langhooks.h
> index b2f0f922b89..27fd5638d21 100644
> --- a/gcc/langhooks.h
> +++ b/gcc/langhooks.h
> @@ -181,6 +181,15 @@ struct lang_hooks_for_decls
> level, i.e. declared outside subprograms. */
> bool (*global_bindings_p) (void);
>
> + /* Given some declaration, if this returns true, we should produce debug
> info
> + for it. We should not do this for languages with poor modules
> definition
> + like C/C++ because translation units make us process a lot of
> declarations
> + that are common to a lot of translation units, bloating the debug info.
> + However this is desirable in languages like Ada, where we know we must
> not
> + produce debug info for the declaration of functions that come from other
> + units (unless in special cases, like cross-unit inlining). */
> + bool (*emit_debug_info_for_decl_p) (tree);
> +
> /* Function to add a decl to the current scope level. Takes one
> argument, a decl to add. Returns that decl, or, if the same
> symbol is already declared, may return a different decl for that
> --
> 2.13.0
>
