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, 36 insertions, 1 deletions

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index e10006c..13998b2 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -79,6 +79,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "output.h"
 #include "expr.h"
 #include "dwarf2out.h"
+#include "dwarf2ctf.h"
 #include "dwarf2asm.h"
 #include "toplev.h"
 #include "md5.h"
@@ -28332,7 +28333,10 @@ dwarf2out_source_line (unsigned int line, unsigned int column,
   dw_line_info_table *table;
   static var_loc_view lvugid;
 
-  if (debug_info_level < DINFO_LEVEL_TERSE)
+  /* 'line_info_table' information gathering is not needed when the debug
+     info level is set to the lowest value.  Also, the current DWARF-based
+     debug formats do not use this info.  */
+  if (debug_info_level < DINFO_LEVEL_TERSE || !dwarf_debuginfo_p ())
     return;
 
   table = cur_line_info_table;
@@ -31876,6 +31880,10 @@ dwarf2out_finish (const char *filename)
   unsigned char checksum[16];
   char dl_section_ref[MAX_ARTIFICIAL_LABEL_BYTES];
 
+  /* Skip emitting DWARF if not required.  */
+  if (!dwarf_debuginfo_p ())
+    return;
+
   /* Flush out any latecomers to the limbo party.  */
   flush_limbo_die_list ();
 
@@ -32631,6 +32639,19 @@ note_variable_value (dw_die_ref die)
   FOR_EACH_CHILD (die, c, note_variable_value (c));
 }
 
+/* Process DWARF dies for CTF generation.  */
+
+static void
+ctf_debug_do_cu (dw_die_ref die)
+{
+  dw_die_ref c;
+
+  if (!ctf_do_die (die))
+    return;
+
+  FOR_EACH_CHILD (die, c, ctf_do_die (c));
+}
+
 /* Perform any cleanups needed after the early debug generation pass
    has run.  */
 
@@ -32753,6 +32774,20 @@ dwarf2out_early_finish (const char *filename)
       print_die (comp_unit_die (), dump_file);
     }
 
+  /* Generate CTF/BTF debug info.  */
+  if ((ctf_debug_info_level > CTFINFO_LEVEL_NONE
+       || btf_debuginfo_p ()) && lang_GNU_C ())
+    {
+      ctf_debug_init ();
+      ctf_debug_do_cu (comp_unit_die ());
+      for (limbo_die_node *node = limbo_die_list; node; node = node->next)
+	ctf_debug_do_cu (node->die);
+      /* Post process the debug data in the CTF container if necessary.  */
+      ctf_debug_init_postprocess (btf_debuginfo_p ());
+      /* Emit CTF/BTF debug info.  */
+      ctf_debug_finalize (filename, btf_debuginfo_p ());
+    }
+
   /* Do not generate DWARF assembler now when not producing LTO bytecode.  */
   if ((!flag_generate_lto && !flag_generate_offload)
       /* FIXME: Disable debug info generation for (PE-)COFF targets since the