include/

	* dwarf2.def (DW_TAG_GNU_annotation): Add link to wiki page
	documenting the extension.
	(DW_AT_GNU_annotation): Likewise.

The btf_decl_tag and btf_type_tag attributes provide a means to annotate
declarations and types respectively with arbitrary user provided
strings.  These strings are recorded in debug information for
post-compilation uses, and despite the name they are meant to be
recorded in DWARF as well as BTF.  New DWARF extensions
DW_TAG_GNU_annotation and DW_AT_GNU_annotation are used to represent
these user annotations in DWARF.

This patch introduces the new DWARF extension DIE and attribute, and
generates them as necessary to represent user annotations from
btf_decl_tag and btf_type_tag.

The format of the new DIE is as follows:

    DW_TAG_GNU_annotation
        DW_AT_name: "btf_decl_tag" or "btf_type_tag"
        DW_AT_const_value: <arbitrary user-supplied string>
        DW_AT_GNU_annotation: <reference to another TAG_GNU_annotation DIE>

DW_AT_GNU_annotation is a new attribute extension used to refer to these
new annotation DIEs.  If non-null in any given declaration or type DIE,
it is a reference to a DW_TAG_GNU_annotation DIE holding an annotation
for that declaration or type.  In addition, the DW_TAG_GNU_annotation
DIEs may also have a non-null DW_AT_GNU_annotation, referring to another
annotation DIE.  This allows chains of annotation DIEs to be formed,
such as in the case where a single declaration has multiple instances of
btf_decl_tag with different string annotations.

gcc/
	* dwarf2out.cc (struct annotation_node, struct annotation_node_hasher)
	(btf_tag_htab): New ancillary structures and hash table.
	(annotation_node_hasher::hash, annotation_node_hasher::equal): New.
	(hash_btf_tag, gen_btf_tag_dies, maybe_gen_btf_type_tag_dies)
	(maybe_gen_btf_decl_tag_dies): New functions.
	(modified_type_die): Add new argument to pass type attributes.
	Handle btf_type_tag, and update recursive calls.
	(base_type_for_mode): Add new arg for modified_type_die call.
	(add_type_attribute): Likewise.
	(gen_array_type_die): Call maybe_gen_btf_type_tag_dies for the type.
	(gen_formal_parameter_die): Call maybe_gen_btf_decl_tag_dies for the
	parameter.
	(override_type_for_decl_p): Add new arg for modified_type_die call.
	(force_type_die): Likewise.
	(gen_tagged_type_die): Call maybe_gen_btf_type_tag_dies for the type.
	(gen_decl_die): Call maybe_gen_btf_decl_tag_dies for the decl.
	(dwarf2out_finish): Empty btf_tag_htab.
	(dwarf2out_cc_finalize): Delete btf_tag_htab hash table.

include/
	* dwarf2.def (DW_TAG_GNU_annotation): New DWARF extension.
	(DW_AT_GNU_annotation): Likewise.

gcc/testsuite/
	* gcc.dg/debug/dwarf2/dwarf-btf-decl-tag-1.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-decl-tag-2.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-decl-tag-3.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-type-tag-1.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-type-tag-2.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-type-tag-3.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-type-tag-4.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-type-tag-5.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-type-tag-6.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-type-tag-7.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-type-tag-8.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-type-tag-9.c: New test.
	* gcc.dg/debug/dwarf2/dwarf-btf-type-tag-10.c: New test.

The contents of include/dwarf2.def have diverged between the gcc and
the binutils repositories.  Currently, it's impossible to build a combined
tree, as GCC won't build with the binutils version of dwarf2.def and binutils
won't build with the gcc version.  This patch realigns this file by copying
the defintion of DW_CFA_AARCH64_negate_ra_state_with_pc from binutils,
restoring the ability to build a combined source tree.

2025-02-11  Roger Sayle  <roger@nextmovesoftware.com>

include/ChangeLog
	* dwarf2.def (DW_CFA_AARCH64_negate_ra_state_with_pc): Define.

DWARF has voted in recently https://dwarfstd.org/issues/241209.1.html ,
which is basically just a guarantee that the DWARF 6 draft
DW_AT_language_{name,version} attribute codes and content of
https://dwarfstd.org/languages-v6.html can be used as an extension
in DWARF 5 and won't be changed.

So, this patch is an alternative to the
https://gcc.gnu.org/pipermail/gcc-patches/2024-November/669671.html
patch, which had the major problem that it required changing all the
DWARF consumers to be able to debug C17 or later or C++17 or later
sources.
This patch uses still DWARF 5 DW_LANG_C11 or DW_LANG_C_plus_plus_14,
the latest code in DWARF 5 proper, so all DWARF 5 capable consumers
should be able to deal with that, but additionally emits the
DWARF 6 attributes so that newer DWARF consumers can see it isn't
just C++14 but say C++23 or C11 but C23.  Consumers which don't know
those DWARF 6 attributes would just ignore them.  This is like any other
-gno-strict-dwarf extension, except that normally we emit say DWARF 5
codes where possible only after DWARF 5 is released, while in this case
there is a guarantee it can be used before DWARF 6 is released.

2025-01-08  Jakub Jelinek  <jakub@redhat.com>

include/
	* dwarf2.h (enum dwarf_source_language): Fix comment pasto.
	(enum dwarf_source_language_name): New type.
	* dwarf2.def (DW_AT_language_name, DW_AT_language_version): New
	DWARF 6 codes.
gcc/
	* dwarf2out.cc (break_out_comdat_types): Copy over
	DW_AT_language_{name,version} if present.
	(output_skeleton_debug_sections): Remove also
	DW_AT_language_{name,version}.
	(gen_compile_unit_die): For C17, C23, C2Y, C++17, C++20, C++23
	and C++26 emit for -gdwarf-5 -gno-strict-dwarf also
	DW_AT_language_{name,version} attributes.
gcc/testsuite/
	* g++.dg/debug/dwarf2/lang-cpp17.C: Add -gno-strict-dwarf to
	dg-options.  Check also for DW_AT_language_{name,version} values.
	* g++.dg/debug/dwarf2/lang-cpp20.C: Likewise.
	* g++.dg/debug/dwarf2/lang-cpp23.C: New test.

I've reimplemented the .debug_names code in GDB -- it was quite far
from being correct, and the new implementation is much closer to what
is specified by DWARF.

However, the new writer in GDB needs to emit some symbol properties,
so that the reader can be fully functional.  This patch adds a few new
DW_IDX_* constants, and tries to document the existing extensions as
well.  (My patch series add more documentation of these to the GDB
manual as well.)

include/ChangeLog
2023-12-10  Tom Tromey  <tom@tromey.com>

	* dwarf2.def (DW_IDX_GNU_internal, DW_IDX_GNU_external): Comment.
	(DW_IDX_GNU_main, DW_IDX_GNU_language, DW_IDX_GNU_linkage_name):
	New constants.

include/
	* dwarf2.def: Correct spelling of DW_AT_namelist_item.
gcc/
	* dwarf2out.cc (gen_namelist_decl): Adjust to suit correct
	spelling of DW_AT_namelist_item.