ctf_add_type(): when looking up an integer or floating point type in the

list of pending dynamic type definitions, a match on the type name is not
sufficient - we need to compare the type encodings as well. For example,
bitfields have their own distinct type definitions which share the name of
the underlying integer type, and these types aren't generally
interchangeable.

This bug was causing the following libdtrace error when attempting to trace
the th_flags member of a struct tcphdr:
  cg: bad field: off 104 type <32877> bits 539620016

Reported by:	rwatson
MFC after:	3 weeks

1 files changed, 17 insertions, 4 deletions

diff --git a/cddl/contrib/opensolaris/common/ctf/ctf_create.c b/cddl/contrib/opensolaris/common/ctf/ctf_create.c
index 1c0988a..a2ca819 100644
--- a/cddl/contrib/opensolaris/common/ctf/ctf_create.c
+++ b/cddl/contrib/opensolaris/common/ctf/ctf_create.c
@@ -1328,15 +1328,28 @@ ctf_add_type(ctf_file_t *dst_fp, ctf_file_t *src_fp, ctf_id_t src_type)
 	 * we are looking for.  This is necessary to permit ctf_add_type() to
 	 * operate recursively on entities such as a struct that contains a
 	 * pointer member that refers to the same struct type.
+	 *
+	 * In the case of integer and floating point types, we match using the
+	 * type encoding as well - else we may incorrectly return a bitfield
+	 * type, for instance.
 	 */
 	if (dst_type == CTF_ERR && name[0] != '\0') {
 		for (dtd = ctf_list_prev(&dst_fp->ctf_dtdefs); dtd != NULL &&
 		    CTF_TYPE_TO_INDEX(dtd->dtd_type) > dst_fp->ctf_dtoldid;
 		    dtd = ctf_list_prev(dtd)) {
-			if (CTF_INFO_KIND(dtd->dtd_data.ctt_info) == kind &&
-			    dtd->dtd_name != NULL &&
-			    strcmp(dtd->dtd_name, name) == 0)
-				return (dtd->dtd_type);
+			if (CTF_INFO_KIND(dtd->dtd_data.ctt_info) != kind ||
+			    dtd->dtd_name == NULL ||
+			    strcmp(dtd->dtd_name, name) != 0)
+				continue;
+			if (kind == CTF_K_INTEGER || kind == CTF_K_FLOAT) {
+				if (ctf_type_encoding(src_fp, src_type,
+				    &src_en) != 0)
+					continue;
+				if (bcmp(&src_en, &dtd->dtd_u.dtu_enc,
+				    sizeof (ctf_encoding_t)) != 0)
+					continue;
+			}
+			return (dtd->dtd_type);
 		}
 	}