[PATCH 5/8] ctfc: Add support to pass through BTF annotations

[David Faust <david.faust@oracle.com>]

BTF generation currently relies on the internal CTF representation to
convert debug info from DWARF dies. This patch adds a new internal
header, "ctf-int.h", which defines CTF kinds to be used internally to
represent BTF tags which must pass through the CTF container. It also
adds a new type for representing information specific to those tags, and
a member for that type in ctf_dtdef.

This patch also updates ctf_add_reftype to accept a const char * name,
and add it for the newly added type.

gcc/

	* ctf-int.h: New file.
	* ctfc.cc (ctf_add_reftype): Add NAME parameter. Pass it to
	ctf_add_generic call.
	(ctf_add_pointer): Update ctf_add_reftype call accordingly.
	* ctfc.h (ctf_add_reftype): Analogous change.
	(ctf_btf_annotation): New.
	(ctf_dtdef): Add member for it.
	(enum ctf_dtu_d_union_enum): Likewise.
	* dwarf2ctf.cc (gen_ctf_modifier_type): Update call to
	ctf_add_reftype accordingly.
---
 gcc/ctf-int.h    | 29 +++++++++++++++++++++++++++++
 gcc/ctfc.cc      | 11 +++++++----
 gcc/ctfc.h       | 17 ++++++++++++++---
 gcc/dwarf2ctf.cc |  2 +-
 4 files changed, 51 insertions(+), 8 deletions(-)
 create mode 100644 gcc/ctf-int.h

diff --git a/gcc/ctf-int.h b/gcc/ctf-int.h
new file mode 100644
index 00000000000..fb5f4aacad6
--- /dev/null
+++ b/gcc/ctf-int.h
@@ -0,0 +1,29 @@
+/* ctf-int.h - GCC internal definitions used for CTF debug info.
+   Copyright (C) 2022 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/>.  */
+
+#ifndef GCC_CTF_INT_H
+#define GCC_CTF_INT_H 1
+
+/* These CTF kinds only exist as a bridge to generating BTF types for
+   BTF_KIND_DECL_TAG and BTF_KIND_TYPE_TAG. They do not correspond to any
+   representable type kind in CTF.  */
+#define CTF_K_DECL_TAG  62
+#define CTF_K_TYPE_TAG  63
+
+#endif /* GCC_CTF_INT_H */
diff --git a/gcc/ctfc.cc b/gcc/ctfc.cc
index 6fe44d2e8d4..031a6fff65d 100644
--- a/gcc/ctfc.cc
+++ b/gcc/ctfc.cc
@@ -107,6 +107,9 @@ ctf_dtu_d_union_selector (ctf_dtdef_ref ctftype)
       return CTF_DTU_D_ARGUMENTS;
     case CTF_K_SLICE:
       return CTF_DTU_D_SLICE;
+    case CTF_K_DECL_TAG:
+    case CTF_K_TYPE_TAG:
+      return CTF_DTU_D_BTFNOTE;
     default:
       /* The largest member as default.  */
       return CTF_DTU_D_ARRAY;
@@ -394,15 +397,15 @@ ctf_add_encoded (ctf_container_ref ctfc, uint32_t flag, const char * name,
 }
 
 ctf_id_t
-ctf_add_reftype (ctf_container_ref ctfc, uint32_t flag, ctf_id_t ref,
-		 uint32_t kind, dw_die_ref die)
+ctf_add_reftype (ctf_container_ref ctfc, uint32_t flag, const char * name,
+		 ctf_id_t ref, uint32_t kind, dw_die_ref die)
 {
   ctf_dtdef_ref dtd;
   ctf_id_t type;
 
   gcc_assert (ref <= CTF_MAX_TYPE);
 
-  type = ctf_add_generic (ctfc, flag, NULL, &dtd, die);
+  type = ctf_add_generic (ctfc, flag, name, &dtd, die);
   dtd->dtd_data.ctti_info = CTF_TYPE_INFO (kind, flag, 0);
   /* Caller of this API must guarantee that a CTF type with id = ref already
      exists.  This will also be validated for us at link-time.  */
@@ -514,7 +517,7 @@ ctf_id_t
 ctf_add_pointer (ctf_container_ref ctfc, uint32_t flag, ctf_id_t ref,
 		 dw_die_ref die)
 {
-  return (ctf_add_reftype (ctfc, flag, ref, CTF_K_POINTER, die));
+  return (ctf_add_reftype (ctfc, flag, NULL, ref, CTF_K_POINTER, die));
 }
 
 ctf_id_t
diff --git a/gcc/ctfc.h b/gcc/ctfc.h
index 18c93c802a0..51f43cd01cb 100644
--- a/gcc/ctfc.h
+++ b/gcc/ctfc.h
@@ -35,6 +35,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "dwarf2ctf.h"
 #include "ctf.h"
 #include "btf.h"
+#include "ctf-int.h"
 
 /* Invalid CTF type ID definition.  */
 
@@ -151,6 +152,13 @@ typedef struct GTY (()) ctf_func_arg
 
 #define ctf_farg_list_next(elem) ((ctf_func_arg_t *)((elem)->farg_next))
 
+/* BTF support: a BTF type tag or decl tag.  */
+
+typedef struct GTY (()) ctf_btf_annotation
+{
+  uint32_t component_idx;
+} ctf_btf_annotation_t;
+
 /* Type definition for CTF generation.  */
 
 struct GTY ((for_user)) ctf_dtdef
@@ -173,6 +181,8 @@ struct GTY ((for_user)) ctf_dtdef
     ctf_func_arg_t * GTY ((tag ("CTF_DTU_D_ARGUMENTS"))) dtu_argv;
     /* slice.  */
     ctf_sliceinfo_t GTY ((tag ("CTF_DTU_D_SLICE"))) dtu_slice;
+    /* btf annotation.  */
+    ctf_btf_annotation_t GTY ((tag ("CTF_DTU_D_BTFNOTE"))) dtu_btfnote;
   } dtd_u;
 };
 
@@ -212,7 +222,8 @@ enum ctf_dtu_d_union_enum {
   CTF_DTU_D_ARRAY,
   CTF_DTU_D_ENCODING,
   CTF_DTU_D_ARGUMENTS,
-  CTF_DTU_D_SLICE
+  CTF_DTU_D_SLICE,
+  CTF_DTU_D_BTFNOTE
 };
 
 enum ctf_dtu_d_union_enum
@@ -396,8 +407,8 @@ extern ctf_dvdef_ref ctf_dvd_lookup (const ctf_container_ref ctfc,
 extern const char * ctf_add_string (ctf_container_ref, const char *,
 				    uint32_t *, int);
 
-extern ctf_id_t ctf_add_reftype (ctf_container_ref, uint32_t, ctf_id_t,
-				 uint32_t, dw_die_ref);
+extern ctf_id_t ctf_add_reftype (ctf_container_ref, uint32_t, const char *,
+				 ctf_id_t, uint32_t, dw_die_ref);
 extern ctf_id_t ctf_add_enum (ctf_container_ref, uint32_t, const char *,
 			      HOST_WIDE_INT, dw_die_ref);
 extern ctf_id_t ctf_add_slice (ctf_container_ref, uint32_t, ctf_id_t,
diff --git a/gcc/dwarf2ctf.cc b/gcc/dwarf2ctf.cc
index 747b2f66107..32495cf4307 100644
--- a/gcc/dwarf2ctf.cc
+++ b/gcc/dwarf2ctf.cc
@@ -511,7 +511,7 @@ gen_ctf_modifier_type (ctf_container_ref ctfc, dw_die_ref modifier)
   gcc_assert (kind != CTF_K_MAX);
   /* Now register the modifier itself.  */
   if (!ctf_type_exists (ctfc, modifier, &modifier_type_id))
-    modifier_type_id = ctf_add_reftype (ctfc, CTF_ADD_ROOT,
+    modifier_type_id = ctf_add_reftype (ctfc, CTF_ADD_ROOT, NULL,
 					qual_type_id, kind,
 					modifier);
 
-- 
2.35.1