[binutils-gdb] libctf: create: addition of non-root types should not return root types

[Nick Alcock]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=84b2be94e5b652d48993d3980b8a3378bd3c6cb5

commit 84b2be94e5b652d48993d3980b8a3378bd3c6cb5
Author: Nick Alcock <nick.alcock@oracle.com>
Date:   Thu Jun 26 15:45:31 2025 +0100

    libctf: create: addition of non-root types should not return root types
    
    If you add a non-root type to a dict, you should always get a new, unique
    type ID back, even if a root-visible type with the same name already exists.
    Unfortunately, if the root-visible type is a forward, and you're adding a
    non-root-visible struct, union, or enum, the machinery to detect forwards
    and promote them to the concrete type fires in this case and returns the
    root-visible type!  If this is an enum being inserted hidden because its
    enumerands conflict with some other enum, this will lead to failure later
    on: in any case, it's seriously counterintuitive to add a non-root- visible
    type and get a root-visible one instead.
    
    Fix this by checking the root-visible flag properly and only checking for
    forwards if this type is root-visible.  (This may lead to a certain degree
    of proliferation of non-root-visible forwards: we can add a cleanup pass for
    those later if needed.)
    
    libctf/
            * ctf-create.c (ctf_add_struct_sized): Check the root-visible flag when
            doing forward promotion.
            (ctf_add_union_sized): Likewise.
            (ctf_add_enum): Likewise.
    
    Reviewed-by: Bruce McCulloch <bruce.mcculloch@oracle.com>

Diff:
---
 libctf/ctf-create.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libctf/ctf-create.c b/libctf/ctf-create.c
index 25dd44def3b..ca984e81b51 100644
--- a/libctf/ctf-create.c
+++ b/libctf/ctf-create.c
@@ -788,7 +788,7 @@ ctf_add_struct_sized (ctf_dict_t *fp, uint32_t flag, const char *name,
   size_t initial_vlen = sizeof (ctf_lmember_t) * INITIAL_VLEN;
 
   /* Promote root-visible forwards to structs.  */
-  if (name != NULL)
+  if (name != NULL && flag == CTF_ADD_ROOT)
     type = ctf_lookup_by_rawname (fp, CTF_K_STRUCT, name);
 
   /* Prohibit promotion if this type was ctf_open()ed.  */
@@ -832,7 +832,7 @@ ctf_add_union_sized (ctf_dict_t *fp, uint32_t flag, const char *name,
   size_t initial_vlen = sizeof (ctf_lmember_t) * INITIAL_VLEN;
 
   /* Promote root-visible forwards to unions.  */
-  if (name != NULL)
+  if (name != NULL && flag == CTF_ADD_ROOT)
     type = ctf_lookup_by_rawname (fp, CTF_K_UNION, name);
 
   /* Prohibit promotion if this type was ctf_open()ed.  */
@@ -875,7 +875,7 @@ ctf_add_enum (ctf_dict_t *fp, uint32_t flag, const char *name)
   size_t initial_vlen = sizeof (ctf_enum_t) * INITIAL_VLEN;
 
   /* Promote root-visible forwards to enums.  */
-  if (name != NULL)
+  if (name != NULL && flag == CTF_ADD_ROOT)
     type = ctf_lookup_by_rawname (fp, CTF_K_ENUM, name);
 
   /* Prohibit promotion if this type was ctf_open()ed.  */