ctf: use pointers instead of IDs internally

This patch replaces all inter-type references in the ctfc internal data
structures with pointers, rather than the references-by-ID which were
used previously.

A couple of small updates in the BPF backend are included to make it
compatible with the change.

This change is only to the in-memory representation of various CTF
structures to make them easier to work with in various cases.  It is
outwardly transparent; there is no change in emitted CTF.

gcc/
	* btfout.cc (BTF_VOID_TYPEID, BTF_INIT_TYPEID): Move defines to
	include/btf.h.
	(btf_dvd_emit_preprocess_cb, btf_emit_preprocess)
	(btf_dmd_representable_bitfield_p, btf_asm_array, btf_asm_varent)
	(btf_asm_sou_member, btf_asm_func_arg, btf_init_postprocess):
	Adapt to structural changes in ctf_* structs.
	* ctfc.h (struct ctf_dtdef): Add forward declaration.
	(ctf_dtdef_t, ctf_dtdef_ref): Move typedefs earlier.
	(struct ctf_arinfo, struct ctf_funcinfo, struct ctf_sliceinfo)
	(struct ctf_itype, struct ctf_dmdef, struct ctf_func_arg)
	(struct ctf_dvdef): Use pointers instead of type IDs for
	references to other types and use typedefs where appropriate.
	(struct ctf_dtdef): Add ref_type member.
	(ctf_type_exists): Use pointer instead of type ID.
	(ctf_add_reftype, ctf_add_enum, ctf_add_slice, ctf_add_float)
	(ctf_add_integer, ctf_add_unknown, ctf_add_pointer)
	(ctf_add_array, ctf_add_forward, ctf_add_typedef)
	(ctf_add_function, ctf_add_sou, ctf_add_enumerator)
	(ctf_add_variable): Likewise. Return pointer instead of ID.
	(ctf_lookup_tree_type): Return pointer to type instead of ID.
	* ctfc.cc: Analogous changes.
	* ctfout.cc (ctf_asm_type, ctf_asm_slice, ctf_asm_varent)
	(ctf_asm_sou_lmember, ctf_asm_sou_member, ctf_asm_func_arg)
	(output_ctf_objt_info): Adapt to changes.
	* dwarf2ctf.cc (gen_ctf_type, gen_ctf_void_type)
	(gen_ctf_unknown_type, gen_ctf_base_type, gen_ctf_pointer_type)
	(gen_ctf_subrange_type, gen_ctf_array_type, gen_ctf_typedef)
	(gen_ctf_modifier_type, gen_ctf_sou_type, gen_ctf_function_type)
	(gen_ctf_enumeration_type, gen_ctf_variable, gen_ctf_function)
	(gen_ctf_type, ctf_do_die): Likewise.
	* config/bpf/btfext-out.cc (struct btf_ext_core_reloc): Use
	pointer instead of type ID.
	(bpf_core_reloc_add, bpf_core_get_sou_member_index)
	(output_btfext_core_sections): Adapt to above changes.
	* config/bpf/core-builtins.cc (process_type): Likewise.

include/
	* btf.h (BTF_VOID_TYPEID, BTF_INIT_TYPEID): Move defines here,
	from gcc/btfout.cc.

2 files changed, 11 insertions, 6 deletions

diff --git a/gcc/config/bpf/btfext-out.cc b/gcc/config/bpf/btfext-out.cc
index 7ec438f..b3df7b5 100644
--- a/gcc/config/bpf/btfext-out.cc
+++ b/gcc/config/bpf/btfext-out.cc
@@ -134,7 +134,7 @@ struct GTY ((chain_next ("%h.next"))) btf_ext_lineinfo
 
 /* Internal representation of a BPF CO-RE relocation record.  */
 struct GTY ((chain_next ("%h.next"))) btf_ext_core_reloc {
-  unsigned int bpfcr_type;		/* BTF type ID of container.  */
+  ctf_dtdef_ref bpfcr_type;		/* BTF type involved in relocation.  */
   unsigned int  bpfcr_astr_off;		/* Offset of access string in .BTF
 					   string table.  */
   rtx_code_label * bpfcr_insn_label;	/* RTX label attached to instruction
@@ -296,13 +296,14 @@ bpf_core_reloc_add (const tree type, const char * section_name,
   struct btf_ext_core_reloc *bpfcr = bpf_create_core_reloc (section_name, &sec);
 
   ctf_container_ref ctfc = ctf_get_tu_ctfc ();
+  ctf_dtdef_ref dtd = ctf_lookup_tree_type (ctfc, type);
 
   /* Buffer the access string in the auxiliary strtab.  */
   bpfcr->bpfcr_astr_off = 0;
   gcc_assert (accessor != NULL);
   bpfcr->bpfcr_astr_off = btf_ext_add_string (accessor);
 
-  bpfcr->bpfcr_type = get_btf_id (ctf_lookup_tree_type (ctfc, type));
+  bpfcr->bpfcr_type = dtd;
   bpfcr->bpfcr_insn_label = label;
   bpfcr->bpfcr_kind = kind;
 
@@ -341,7 +342,8 @@ bpf_core_get_sou_member_index (ctf_container_ref ctfc, const tree node)
       for (dmd = dtd->dtd_u.dtu_members;
            dmd != NULL; dmd = (ctf_dmdef_t *) ctf_dmd_list_next (dmd))
         {
-	  bool field_has_btf = get_btf_id (dmd->dmd_type) <= BTF_MAX_TYPE;
+	  bool field_has_btf = (dmd->dmd_type
+				&& dmd->dmd_type->dtd_type <= BTF_MAX_TYPE);
 
 	  if (field == node)
 	    return field_has_btf ? i : -1;
@@ -574,8 +576,10 @@ output_btfext_core_sections (void)
 				 false);
 	      char *str = xstrdup (pp_formatted_text (&pp));
 
-	      dw2_asm_output_data (4, bpfcr->bpfcr_type, "bpfcr_type (%s)",
-				   str);
+	      uint32_t type_id = bpfcr->bpfcr_type
+		? bpfcr->bpfcr_type->dtd_type
+		: BTF_VOID_TYPEID;
+	      dw2_asm_output_data (4, type_id, "bpfcr_type (%s)", str);
 	      dw2_asm_output_data (4, bpfcr->bpfcr_astr_off + str_aux_off,
 				   "bpfcr_astr_off (\"%s\")",
 				   bpfcr->info.accessor_str);
diff --git a/gcc/config/bpf/core-builtins.cc b/gcc/config/bpf/core-builtins.cc
index 829acea..232bebc 100644
--- a/gcc/config/bpf/core-builtins.cc
+++ b/gcc/config/bpf/core-builtins.cc
@@ -1021,7 +1021,8 @@ process_type (struct cr_builtins *data)
       && data->default_value != NULL)
   {
     ctf_container_ref ctfc = ctf_get_tu_ctfc ();
-    unsigned int btf_id = get_btf_id (ctf_lookup_tree_type (ctfc, ret.type));
+    ctf_dtdef_ref dtd = ctf_lookup_tree_type (ctfc, ret.type);
+    unsigned int btf_id = dtd ? dtd->dtd_type : BTF_VOID_TYPEID;
     data->rtx_default_value = expand_normal (build_int_cst (integer_type_node,
 							    btf_id));
   }