libctf: map from old to corresponding newly-added types in ctf_add_type

This lets you call ctf_type_mapping (dest_fp, src_fp, src_type_id)
and get told what type ID the corresponding type has in the target
ctf_file_t.  This works even if it was added by a recursive call, and
because it is stored in the target ctf_file_t it works even if we
had to add one type to multiple ctf_file_t's as part of conflicting
type handling.

We empty out this mapping after every archive is linked: because it maps
input to output fps, and we only visit each input fp once, its contents
are rendered entirely useless every time the source fp changes.

v3: add several missing mapping additions.  Add ctf_dynhash_empty, and
    empty after every input archive.
v5: fix tabdamage.

libctf/
	* ctf-impl.h (ctf_file_t): New field ctf_link_type_mapping.
	(struct ctf_link_type_mapping_key): New.
	(ctf_hash_type_mapping_key): Likewise.
	(ctf_hash_eq_type_mapping_key): Likewise.
	(ctf_add_type_mapping): Likewise.
	(ctf_type_mapping): Likewise.
	(ctf_dynhash_empty): Likewise.
	* ctf-open.c (ctf_file_close): Update accordingly.
	* ctf-create.c (ctf_update): Likewise.
	(ctf_add_type): Populate the mapping.
	* ctf-hash.c (ctf_hash_type_mapping_key): Hash a type mapping key.
	(ctf_hash_eq_type_mapping_key): Check the key for equality.
	(ctf_dynhash_insert): Fix comment typo.
	(ctf_dynhash_empty): New.
	* ctf-link.c (ctf_add_type_mapping): New.
	(ctf_type_mapping): Likewise.
	(empty_link_type_mapping): New.
	(ctf_link_one_input_archive): Call it.

1 files changed, 29 insertions, 1 deletions

diff --git a/libctf/ctf-hash.c b/libctf/ctf-hash.c
index 3512d22..c6233eb 100644
--- a/libctf/ctf-hash.c
+++ b/libctf/ctf-hash.c
@@ -82,6 +82,28 @@ ctf_hash_eq_string (const void *a, const void *b)
   return !strcmp((const char *) hep_a->key, (const char *) hep_b->key);
 }
 
+/* Hash a type_mapping_key.  */
+unsigned int
+ctf_hash_type_mapping_key (const void *ptr)
+{
+  ctf_helem_t *hep = (ctf_helem_t *) ptr;
+  ctf_link_type_mapping_key_t *k = (ctf_link_type_mapping_key_t *) hep->key;
+
+  return htab_hash_pointer (k->cltm_fp) + 59 * htab_hash_pointer ((void *) k->cltm_idx);
+}
+
+int
+ctf_hash_eq_type_mapping_key (const void *a, const void *b)
+{
+  ctf_helem_t *hep_a = (ctf_helem_t *) a;
+  ctf_helem_t *hep_b = (ctf_helem_t *) b;
+  ctf_link_type_mapping_key_t *key_a = (ctf_link_type_mapping_key_t *) hep_a->key;
+  ctf_link_type_mapping_key_t *key_b = (ctf_link_type_mapping_key_t *) hep_b->key;
+
+  return (key_a->cltm_fp == key_b->cltm_fp)
+    && (key_a->cltm_idx == key_b->cltm_idx);
+}
+
 /* The dynhash, used for hashes whose size is not known at creation time. */
 
 /* Free a single ctf_helem.  */
@@ -164,7 +186,7 @@ ctf_dynhash_insert (ctf_dynhash_t *hp, void *key, void *value)
     return errno;
 
   /* We need to keep the key_free and value_free around in each item because the
-     del function has no visiblity into the hash as a whole, only into the
+     del function has no visibility into the hash as a whole, only into the
      individual items.  */
 
   slot->key_free = hp->key_free;
@@ -180,6 +202,12 @@ ctf_dynhash_remove (ctf_dynhash_t *hp, const void *key)
   htab_remove_elt (hp->htab, &hep);
 }
 
+void
+ctf_dynhash_empty (ctf_dynhash_t *hp)
+{
+  htab_empty (hp->htab);
+}
+
 void *
 ctf_dynhash_lookup (ctf_dynhash_t *hp, const void *key)
 {