CTF/BTF debug formats

This commit introduces support for generating CTF debugging
information and BTF debugging information from GCC.

2021-06-28  Indu Bhagat  <indu.bhagat@oracle.com>
	    David Faust  <david.faust@oracle.com>
	    Jose E. Marchesi  <jose.marchesi@oracle.com>
	    Weimin Pan  <weimin.pan@oracle.com>

gcc/

	* Makefile.in: Add ctfc.*, ctfout.c and btfout.c files to
	GTFILES.  Add new object files.
	* common.opt: Add CTF and BTF debug info options.
	* btfout.c: New file.
	* ctfc.c: Likewise.
	* ctfc.h: Likewise.
	* ctfout.c: Likewise.
	* dwarf2ctf.c: Likewise.
	* dwarf2ctf.h: Likewise.
	* dwarf2cfi.c (dwarf2out_do_frame): Acknowledge CTF_DEBUG and
	BTF_DEBUG.
	* dwarf2out.c (dwarf2out_source_line): Likewise.
	(dwarf2out_finish): Skip emitting DWARF if CTF or BTF are to
	be generated.
	(debug_format_do_cu): New function.
	(dwarf2out_early_finish): Traverse DIEs and emit CTF/BTF for
	them if	requested.
	Include dwarf2ctf.c.
	* final.c (dwarf2_debug_info_emitted_p): Acknowledge DWARF-based debug
	formats.
	* flag-types.h (enum debug_info_type): Add CTF_DEBUG and BTF_DEBUG.
	(CTF_DEBUG): New bitmask.
	(BTF_DEBUG): Likewise.
	(enum ctf_debug_info_levels): New enum.
	* gengtype.c (open_base_files): Handle ctfc.h.
	(main): Handle uint32_t type.
	* flags.h (btf_debuginfo_p): New definition.
	(dwarf_based_debuginfo_p): Likewise.
	* opts.c (debug_type_names): Add entries for CTF and BTF.
	(btf_debuginfo_p): New function.
	(dwarf_based_debuginfo_p): Likewise.
	(common_handle_option): Handle -gctfN and -gbtf options.
	(set_debug_level): Set CTF_DEBUG, BTF_DEBUG whenever appropriate.
	* toplev.c (process_options): Inform the user and ignore -gctfLEVEL if
	frontend is not C.

include/

	* ctf.h: New file.
	* btf.h: Likewise.

libiberty/

	* simple-object.c (handle_lto_debug_sections): Copy over .ctf
	sections.

1 files changed, 53 insertions, 0 deletions

diff --git a/gcc/dwarf2ctf.h b/gcc/dwarf2ctf.h
new file mode 100644
index 0000000..a3cf567
--- /dev/null
+++ b/gcc/dwarf2ctf.h
@@ -0,0 +1,53 @@
+/* dwarf2ctf.h - DWARF interface for CTF/BTF generation.
+   Copyright (C) 2021 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+/* This file contains declarations and prototypes to define an interface
+   between DWARF and CTF/BTF generation.  */
+
+#ifndef GCC_DWARF2CTF_H
+#define GCC_DWARF2CTF_H 1
+
+#include "dwarf2out.h"
+
+/* Debug Format Interface.  Used in dwarf2out.c.  */
+
+extern void ctf_debug_init (void);
+extern void ctf_debug_init_postprocess (bool);
+extern bool ctf_do_die (dw_die_ref);
+extern void ctf_debug_finalize (const char *, bool);
+
+/* Wrappers for CTF/BTF to fetch information from GCC DWARF DIE.  Used in
+   ctfc.c.
+
+   A CTF container does not store all debug information internally.  Some of
+   the info is fetched indirectly via the DIE reference available in each CTF
+   container entry.
+
+   These functions will be used by the CTF container to give access to its
+   consumers (CTF/BTF) to various debug information available in DWARF DIE.
+   Direct access to debug information in GCC dwarf structures by the consumers
+   of CTF/BTF information is not ideal.  */
+
+/* Source location information.  */
+
+extern const char * ctf_get_die_loc_file (dw_die_ref);
+extern unsigned int ctf_get_die_loc_line (dw_die_ref);
+extern unsigned int ctf_get_die_loc_col (dw_die_ref);
+
+#endif /* GCC_DWARF2CTF_H */