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.

1 files changed, 47 insertions, 43 deletions

diff --git a/gcc/ctfc.h b/gcc/ctfc.h
index e7bd939..b2060ea 100644
--- a/gcc/ctfc.h
+++ b/gcc/ctfc.h
@@ -48,6 +48,10 @@ along with GCC; see the file COPYING3.  If not see
 
 typedef uint64_t ctf_id_t;
 
+struct ctf_dtdef;
+typedef struct ctf_dtdef ctf_dtdef_t;
+typedef ctf_dtdef_t * ctf_dtdef_ref;
+
 /* CTF string table element (list node).  */
 
 typedef struct GTY ((chain_next ("%h.cts_next"))) ctf_string
@@ -81,8 +85,8 @@ typedef struct GTY (()) ctf_encoding
 
 typedef struct GTY (()) ctf_arinfo
 {
-  ctf_id_t ctr_contents;	/* Type of array contents.  */
-  ctf_id_t ctr_index;		/* Type of array index.  */
+  ctf_dtdef_ref ctr_contents;	/* Type of array contents.  */
+  ctf_dtdef_ref ctr_index;	/* Type of array index.  */
   unsigned int ctr_nelems;	/* Number of elements.  */
 } ctf_arinfo_t;
 
@@ -90,14 +94,14 @@ typedef struct GTY (()) ctf_arinfo
 
 typedef struct GTY (()) ctf_funcinfo
 {
-  ctf_id_t ctc_return;		/* Function return type.  */
-  unsigned int ctc_argc;	/* Number of typed arguments to function.  */
-  unsigned int ctc_flags;	/* Function attributes (see below).  */
+  ctf_dtdef_ref ctc_return;	 /* Function return type.  */
+  unsigned int ctc_argc;	 /* Number of typed arguments to function.  */
+  unsigned int ctc_flags;	 /* Function attributes (see below).  */
 } ctf_funcinfo_t;
 
 typedef struct GTY (()) ctf_sliceinfo
 {
-  unsigned int cts_type;	/* Reference CTF type.  */
+  ctf_dtdef_ref cts_type;	/* Reference CTF type.  */
   unsigned short cts_offset;	/* Offset in bits of the first bit.  */
   unsigned short cts_bits;	/* Size in bits.  */
 } ctf_sliceinfo_t;
@@ -130,7 +134,7 @@ typedef struct GTY (()) ctf_itype
 typedef struct GTY ((chain_next ("%h.dmd_next"))) ctf_dmdef
 {
   const char * dmd_name;	/* Name of this member.  */
-  ctf_id_t dmd_type;		/* Type of this member (for sou).  */
+  ctf_dtdef_ref dmd_type;	/* Type of this member (for sou).  */
   uint32_t dmd_name_offset;	/* Offset of the name in str table.  */
   uint64_t dmd_offset;		/* Offset of this member in bits (for sou).  */
   HOST_WIDE_INT dmd_value;	/* Value of this member (for enum).  */
@@ -143,7 +147,7 @@ typedef struct GTY ((chain_next ("%h.dmd_next"))) ctf_dmdef
 
 typedef struct GTY (()) ctf_func_arg
 {
-  ctf_id_t farg_type;		  /* Type identifier of the argument.  */
+  ctf_dtdef_ref farg_type;	  /* Type of the argument.  */
   const char * farg_name;	  /* Name of the argument.  */
   uint32_t farg_name_offset;	  /* Offset of the name in str table.  */
   struct ctf_func_arg * farg_next;/* A list node.  */
@@ -158,6 +162,7 @@ struct GTY ((for_user)) ctf_dtdef
   dw_die_ref dtd_key;	      /* Type key for hashing.  */
   const char * dtd_name;      /* Name associated with definition (if any).  */
   ctf_id_t dtd_type;	      /* Type identifier for this definition.  */
+  ctf_dtdef_ref ref_type;     /* Type referred to by this type (if any).  */
   ctf_itype_t dtd_data;	      /* Type node.  */
   bool from_global_func; /* Whether this type was added from a global
 			    function.  */
@@ -178,7 +183,7 @@ struct GTY ((for_user)) ctf_dtdef
   } dtd_u;
 };
 
-typedef struct ctf_dtdef ctf_dtdef_t;
+#define ctf_type_id(dtd) ((uint32_t) dtd->dtd_type)
 
 /* Variable definition for CTF generation.  */
 
@@ -188,13 +193,11 @@ struct GTY ((for_user)) ctf_dvdef
   const char * dvd_name;	/* Name associated with variable.  */
   uint32_t dvd_name_offset;	/* Offset of the name in str table.  */
   unsigned int dvd_visibility;	/* External visibility.  0=static,1=global.  */
-  ctf_id_t dvd_type;		/* Type of variable.  */
+  ctf_dtdef_ref dvd_type;	/* Type of variable.  */
 };
 
 typedef struct ctf_dvdef ctf_dvdef_t;
-
 typedef ctf_dvdef_t * ctf_dvdef_ref;
-typedef ctf_dtdef_t * ctf_dtdef_ref;
 
 /* Location information for CTF Types and CTF Variables.  */
 
@@ -390,7 +393,7 @@ extern void btf_finalize (void);
 
 extern ctf_container_ref ctf_get_tu_ctfc (void);
 
-extern bool ctf_type_exists (ctf_container_ref, dw_die_ref, ctf_id_t *);
+extern bool ctf_type_exists (ctf_container_ref, dw_die_ref, ctf_dtdef_ref *);
 
 extern void ctf_add_cuname (ctf_container_ref, const char *);
 
@@ -404,41 +407,42 @@ extern bool ctf_dvd_ignore_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_enum (ctf_container_ref, uint32_t, const char *,
-			      HOST_WIDE_INT, bool, dw_die_ref);
-extern ctf_id_t ctf_add_slice (ctf_container_ref, uint32_t, ctf_id_t,
-			       uint32_t, uint32_t, dw_die_ref);
-extern ctf_id_t ctf_add_float (ctf_container_ref, uint32_t, const char *,
-			       const ctf_encoding_t *, dw_die_ref);
-extern ctf_id_t ctf_add_integer (ctf_container_ref, uint32_t, const char *,
-				 const ctf_encoding_t *, dw_die_ref);
-extern ctf_id_t ctf_add_unknown (ctf_container_ref, uint32_t, const char *,
-				 const ctf_encoding_t *, dw_die_ref);
-extern ctf_id_t ctf_add_pointer (ctf_container_ref, uint32_t, ctf_id_t,
-				 dw_die_ref);
-extern ctf_id_t ctf_add_array (ctf_container_ref, uint32_t,
-			       const ctf_arinfo_t *, dw_die_ref);
-extern ctf_id_t ctf_add_forward (ctf_container_ref, uint32_t, const char *,
-				 uint32_t, dw_die_ref);
-extern ctf_id_t ctf_add_typedef (ctf_container_ref, uint32_t, const char *,
-				 ctf_id_t, dw_die_ref);
-extern ctf_id_t ctf_add_function (ctf_container_ref, uint32_t, const char *,
-				  const ctf_funcinfo_t *, dw_die_ref, bool, int);
-extern ctf_id_t ctf_add_sou (ctf_container_ref, uint32_t, const char *,
-			     uint32_t, size_t, dw_die_ref);
-
-extern int ctf_add_enumerator (ctf_container_ref, ctf_id_t, const char *,
+extern ctf_dtdef_ref ctf_add_reftype (ctf_container_ref, uint32_t,
+				      ctf_dtdef_ref, uint32_t, dw_die_ref);
+extern ctf_dtdef_ref ctf_add_enum (ctf_container_ref, uint32_t, const char *,
+				   HOST_WIDE_INT, bool, dw_die_ref);
+extern ctf_dtdef_ref ctf_add_slice (ctf_container_ref, uint32_t, ctf_dtdef_ref,
+				    uint32_t, uint32_t, dw_die_ref);
+extern ctf_dtdef_ref ctf_add_float (ctf_container_ref, uint32_t, const char *,
+				    const ctf_encoding_t *, dw_die_ref);
+extern ctf_dtdef_ref ctf_add_integer (ctf_container_ref, uint32_t, const char *,
+				      const ctf_encoding_t *, dw_die_ref);
+extern ctf_dtdef_ref ctf_add_unknown (ctf_container_ref, uint32_t, const char *,
+				      const ctf_encoding_t *, dw_die_ref);
+extern ctf_dtdef_ref ctf_add_pointer (ctf_container_ref, uint32_t,
+				      ctf_dtdef_ref, dw_die_ref);
+extern ctf_dtdef_ref ctf_add_array (ctf_container_ref, uint32_t,
+				    const ctf_arinfo_t *, dw_die_ref);
+extern ctf_dtdef_ref ctf_add_forward (ctf_container_ref, uint32_t, const char *,
+				      uint32_t, dw_die_ref);
+extern ctf_dtdef_ref ctf_add_typedef (ctf_container_ref, uint32_t, const char *,
+				      ctf_dtdef_ref, dw_die_ref);
+extern ctf_dtdef_ref ctf_add_function (ctf_container_ref, uint32_t,
+				       const char *, const ctf_funcinfo_t *,
+				       dw_die_ref, bool, int);
+extern ctf_dtdef_ref ctf_add_sou (ctf_container_ref, uint32_t, const char *,
+				  uint32_t, size_t, dw_die_ref);
+
+extern int ctf_add_enumerator (ctf_container_ref, ctf_dtdef_ref, const char *,
 			       HOST_WIDE_INT, dw_die_ref);
 extern int ctf_add_member_offset (ctf_container_ref, dw_die_ref, const char *,
-				  ctf_id_t, uint64_t);
+				  ctf_dtdef_ref, uint64_t);
 extern int ctf_add_function_arg (ctf_container_ref, dw_die_ref,
-				 const char *, ctf_id_t);
-extern int ctf_add_variable (ctf_container_ref, const char *, ctf_id_t,
+				 const char *, ctf_dtdef_ref);
+extern int ctf_add_variable (ctf_container_ref, const char *, ctf_dtdef_ref,
 			     dw_die_ref, unsigned int, dw_die_ref);
 
-extern ctf_id_t ctf_lookup_tree_type (ctf_container_ref, const tree);
+extern ctf_dtdef_ref ctf_lookup_tree_type (ctf_container_ref, const tree);
 extern ctf_id_t get_btf_id (ctf_id_t);
 
 typedef bool (*funcs_traverse_callback) (ctf_dtdef_ref, void *);