libctf: rip out dead code handling typedefs with no name

There is special code in libctf to handle typedefs with no name, which
the code calls "anonymous typedef nodes".

These monsters are obviously not something C programs can include: the
whole point of a ttypedef is to introduce a new name.  Looking back at
the history of DWARF in GCC, the only thing (outside C++ anonymous
namespaces) which can generate a DW_TAG_typedef without a DW_AT_name is
obsolete code to handle the long-removed -feliminate-dwarf2-dups option.
Looking at OpenSolaris, typedef nodes with no name couldn't be generated
by the DWARF->CTF converter at all (and its deduplicator barfed on
them): the only reason for the existence of this code is a special case
working around a peculiarity of stabs whereby types could sometimes be
referenced before they were introduced.

We don't need to carry code in libctf to handle special cases in an
obsolete OpenSolaris converter (that yields a format that isn't readable
by libctf anyway).  So drop it.

libctf/ChangeLog
2021-01-27  Nick Alcock  <nick.alcock@oracle.com>

	* ctf-open.c (init_types): Rip out code to check anonymous typedef
	nodes.
	* ctf-create.c (ctf_add_reftype): Likewise.
	* ctf-lookup.c (refresh_pptrtab): Likewise.

diff --git a/libctf/ChangeLog b/libctf/ChangeLog
index eaecb174be2b29441396974382f5430b39fb44d1..9b0dad92b0710e9c9e470cb916d5310242ab329a 100644 (file)
--- a/libctf/ChangeLog
+++ b/libctf/ChangeLog
@@ -1,3 +1,10 @@
+2021-01-27  Nick Alcock  <nick.alcock@oracle.com>
+
+       * ctf-open.c (init_types): Rip out code to check anonymous typedef
+       nodes.
+       * ctf-create.c (ctf_add_reftype): Likewise.
+       * ctf-lookup.c (refresh_pptrtab): Likewise.
+
 2021-01-27  Nick Alcock  <nick.alcock@oracle.com>
 
        * ctf-impl.c (_libctf_nonnull_): Add parameters.

diff --git a/libctf/ctf-create.c b/libctf/ctf-create.c
index c5f79d167adf326affbed464780d36b749ca6d0a..cf47384284687aa849aea716aac73bf4c6ffb2da 100644 (file)
--- a/libctf/ctf-create.c
+++ b/libctf/ctf-create.c
@@ -1629,29 +1629,18 @@ ctf_add_reftype (ctf_dict_t *fp, uint32_t flag, ctf_id_t ref, uint32_t kind)
   if (kind != CTF_K_POINTER)
     return type;
 
-  /* If we are adding a pointer, update the ptrtab, both the directly pointed-to
-     type and (if an anonymous typedef node is being pointed at) the type that
-     points at too.  Note that ctf_typemax is at this point one higher than we
-     want to check against, because it's just been incremented for the addition
-     of this type.  The pptrtab is lazily-updated as needed, so is not touched
-     here.  */
+  /* If we are adding a pointer, update the ptrtab, pointing at this type from
+     the type it points to.  Note that ctf_typemax is at this point one higher
+     than we want to check against, because it's just been incremented for the
+     addition of this type.  The pptrtab is lazily-updated as needed, so is not
+     touched here.  */
 
   uint32_t type_idx = LCTF_TYPE_TO_INDEX (fp, type);
   uint32_t ref_idx = LCTF_TYPE_TO_INDEX (fp, ref);
 
   if (LCTF_TYPE_ISCHILD (fp, ref) == child
       && ref_idx < fp->ctf_typemax)
-    {
-      fp->ctf_ptrtab[ref_idx] = type_idx;
-
-      ctf_id_t refref_idx = LCTF_TYPE_TO_INDEX (fp, dtd->dtd_data.ctt_type);
-
-      if (tmp == fp
-         && (LCTF_INFO_KIND (fp, dtd->dtd_data.ctt_info) == CTF_K_TYPEDEF)
-         && strcmp (ctf_strptr (fp, dtd->dtd_data.ctt_name), "") == 0
-         && refref_idx < fp->ctf_typemax)
-       fp->ctf_ptrtab[refref_idx] = type_idx;
-    }
+    fp->ctf_ptrtab[ref_idx] = type_idx;
 
   return type;
 }

diff --git a/libctf/ctf-lookup.c b/libctf/ctf-lookup.c
index 6d4e085838c0b205cc75dadf38042c573042c7d3..72f6a2a24c7062b961186d052fadac5309c9543b 100644 (file)
--- a/libctf/ctf-lookup.c
+++ b/libctf/ctf-lookup.c
@@ -51,7 +51,6 @@ refresh_pptrtab (ctf_dict_t *fp, ctf_dict_t *pfp)
     {
       ctf_id_t type = LCTF_INDEX_TO_TYPE (fp, i, 1);
       ctf_id_t reffed_type;
-      int updated;
 
       if (ctf_type_kind (fp, type) != CTF_K_POINTER)
        continue;
@@ -65,29 +64,6 @@ refresh_pptrtab (ctf_dict_t *fp, ctf_dict_t *pfp)
          /* Guard against references to invalid types.  No need to consider
             the CTF dict corrupt in this case: this pointer just can't be a
             pointer to any type we know about.  */
-         if (idx <= pfp->ctf_typemax)
-           {
-             if (idx >= fp->ctf_pptrtab_len
-                 && grow_pptrtab (fp, pfp->ctf_ptrtab_len) < 0)
-               return -1;                      /* errno is set for us.  */
-
-             fp->ctf_pptrtab[idx] = i;
-             updated = 1;
-           }
-       }
-      if (!updated)
-       continue;
-
-      /* If we updated the ptrtab entry for this type's referent, and it's an
-        anonymous typedef node, we also want to chase down its referent and
-        change that as well.  */
-
-      if ((ctf_type_kind (fp, reffed_type) == CTF_K_TYPEDEF)
-         && strcmp (ctf_type_name_raw (fp, reffed_type), "") == 0)
-       {
-         uint32_t idx;
-         idx = LCTF_TYPE_TO_INDEX (pfp, ctf_type_reference (fp, reffed_type));
-
          if (idx <= pfp->ctf_typemax)
            {
              if (idx >= fp->ctf_pptrtab_len

diff --git a/libctf/ctf-open.c b/libctf/ctf-open.c
index a92668fd35f06eae5bcd4eb1037e542d49c18c32..67d9f84c361820ced0bb2865ee2ffcccb8657ae8 100644 (file)
--- a/libctf/ctf-open.c
+++ b/libctf/ctf-open.c
@@ -683,7 +683,7 @@ init_types (ctf_dict_t *fp, ctf_header_t *cth)
 
   unsigned long pop[CTF_K_MAX + 1] = { 0 };
   const ctf_type_t *tp;
-  uint32_t id, dst;
+  uint32_t id;
   uint32_t *xp;
 
   /* We determine whether the dict is a child or a parent based on the value of
@@ -953,25 +953,6 @@ init_types (ctf_dict_t *fp, ctf_header_t *cth)
   ctf_dprintf ("%u base type names hashed\n",
               ctf_hash_size (fp->ctf_names.ctn_readonly));
 
-  /* Make an additional pass through the pointer table to find pointers that
-     point to anonymous typedef nodes.  If we find one, modify the pointer table
-     so that the pointer is also known to point to the node that is referenced
-     by the anonymous typedef node.  */
-
-  for (id = 1; id <= fp->ctf_typemax; id++)
-    {
-      if ((dst = fp->ctf_ptrtab[id]) != 0)
-       {
-         tp = LCTF_INDEX_TO_TYPEPTR (fp, id);
-
-         if (LCTF_INFO_KIND (fp, tp->ctt_info) == CTF_K_TYPEDEF
-             && strcmp (ctf_strptr (fp, tp->ctt_name), "") == 0
-             && LCTF_TYPE_ISCHILD (fp, tp->ctt_type) == child
-             && LCTF_TYPE_TO_INDEX (fp, tp->ctt_type) <= fp->ctf_typemax)
-             fp->ctf_ptrtab[LCTF_TYPE_TO_INDEX (fp, tp->ctt_type)] = dst;
-       }
-    }
-
   return 0;
 }