[04/12] bfd, include, ld, binutils, libctf: CTF should use the dynstr/sym

Message ID 20201025141413.363381-5-nick.alcock@oracle.com
State New
Headers show
Series
  • CTF symbol functionality
Related show

Commit Message

Andreas Krebbel via Binutils Oct. 25, 2020, 2:14 p.m.
This is embarrassing.

The whole point of CTF is that it remains intact even after a binary is
stripped, providing a compact mapping from symbols to types for
everything in the externally-visible interface of an ELF object: it has
connections to the symbol table for that purpose, and to the string
table to avoid duplicating symbol names.  So it's a shame that the hooks
I implemented last year served to hook it up to the .symtab and .strtab,
which obviously disappear on strip, leaving any accompanying the CTF
dict containing references to strings (and, soon, symbols) which don't
exist any more because their containing strtab has been vaporized.  The
original Solaris design used .dynsym and .dynstr (well, actually,
.ldynsym, which has more symbols) which do not disappear. So should we.

Thankfully the work we did before serves as guide rails, and adjusting
things to use the .dynstr and .dynsym was fast and easy.  The only
annoyance is that the dynsym is assembled inside elflink.c in a fairly
piecemeal fashion, so that the easiest way to get the symbols out was to
hook in before every call to swap_symbol_out (we also leave in a hook in
front of symbol additions to the .symtab because it seems plausible that
we might want to hook them in future too: for now that hook is unused).
We adjust things so that rather than being offered a whole hash table of
symbols at once, libctf is now given symbols one at a time, with st_name
indexes already resolved and pointing at their final .dynstr offsets:
it's now up to libctf to resolve these to names as needed using the
strtab info we pass it separately.

Some bits might be contentious.  The ctf_new_dynstr callback takes an
elf_internal_sym, and this remains an elf_internal_sym right down
through the generic emulation layers into ldelfgen.  This is no worse
than the elf_sym_strtab we used to pass down, but in the future when we
gain non-ELF CTF symtab support we might want to lower the
elf_internal_sym to some other representation (perhaps a
ctf_link_symbol) in bfd or in ldlang_ctf_new_dynsym.  We rename the
'apply_strsym' hooks to 'acquire_strings' instead, becuse they no longer
have anything to do with symbols.

There are some API changes to pieces of API which are technically public
but actually totally unused by anything and/or unused by anything but ld
so they can change freely: the ctf_link_symbol gains new fields to allow
symbol names to be given as strtab offsets as well as strings, and a
symidx so that the symbol index can be passed in.  ctf_link_shuffle_syms
loses its callback parameter: the idea now is that linkers call the new
ctf_link_add_linker_symbol for every symbol in .dynsym, feed in all the
strtab entries with ctf_link_add_strtab, and then a call to
ctf_link_shuffle_syms will apply both and arrange to use them to reorder
the CTF symtab at CTF serialization time (which is coming in the next
commit).

Inside libctf we have a new preamble flag CTF_F_DYNSTR which is always
set in v3-format CTF dicts from this commit forwards: CTF dicts without
this flag are associated with .strtab like they used to be, so that old
dicts' external strings don't turn to garbage when loaded by new libctf.
Dicts with this flag are associated with .dynstr and .dynsym instead.
(The flag is not the next in sequence because this commit was written
quite late: the missing flags will be filled in by the next commit.)

Tests forthcoming in a later commit in this series.

bfd/ChangeLog
2020-10-25  Nick Alcock  <nick.alcock@oracle.com>

	* elflink.c (elf_finalize_dynstr): Call examine_strtab after
	dynstr finalization.
	(elf_link_swap_symbols_out): Don't call it here.  Call
	ctf_new_symbol before swap_symbol_out.
	(elf_link_output_extsym): Call ctf_new_dynsym before
	swap_symbol_out.
	(bfd_elf_final_link): Likewise.
	* elf.c (swap_out_syms): Pass in bfd_link_info.  Call
	ctf_new_symbol before swap_symbol_out.
	(_bfd_elf_compute_section_file_positions): Adjust.

binutils/ChangeLog
2020-10-25  Nick Alcock  <nick.alcock@oracle.com>

	* readelf.c (dump_section_as_ctf): Use .dynsym and .dynstr, not
	.symtab and .strtab.

include/ChangeLog
2020-10-23  Nick Alcock  <nick.alcock@oracle.com>

	* bfdlink.h (struct elf_sym_strtab): Replace with...
	(struct elf_internal_sym): ... this.
	(struct bfd_link_callbacks) <examine_strtab>: Take only a
	symstrtab argument.
	<ctf_new_symbol>: New.
	<ctf_new_dynsym>: Likewise.
	* ctf-api.h (struct ctf_link_sym) <st_symidx>: New.
	<st_nameidx>: Likewise.
	<st_nameidx_set>: Likewise.
	(ctf_link_iter_symbol_f): Removed.
	(ctf_link_shuffle_syms): Remove most parameters, just takes a
	ctf_dict_t now.
	(ctf_link_add_linker_symbol): New, split from
	ctf_link_shuffle_syms.
	* ctf.h (CTF_F_DYNSTR): New.
	(CTF_F_MAX): Adjust.

ld/ChangeLog
2020-10-25  Nick Alcock  <nick.alcock@oracle.com>

	* ldelfgen.c (struct ctf_strsym_iter_cb_arg): Rename to...
	(struct ctf_strtab_iter_cb_arg): ... this, changing fields:
	<syms>: Remove.
	<symcount>: Remove.
	<symstrtab>: Rename to...
	<strtab>: ... this.
	(ldelf_ctf_strtab_iter_cb): Adjust.
	(ldelf_ctf_symbols_iter_cb): Remove.
	(ldelf_new_dynsym_for_ctf): New, tell libctf about a single
	symbol.
	(ldelf_examine_strtab_for_ctf): Rename to...
	(ldelf_acquire_strings_for_ctf): ... this, only doing the strtab
	portion and not symbols.
	* ldelfgen.h: Adjust declarations accordingly.
	* ldemul.c (ldemul_examine_strtab_for_ctf): Rename to...
	(ldemul_acquire_strings_for_ctf): ... this.
	(ldemul_new_dynsym_for_ctf): New.
	* ldemul.h: Adjust declarations accordingly.
	* ldlang.c (ldlang_ctf_apply_strsym): Rename to...
	(ldlang_ctf_acquire_strings): ... this.
	(ldlang_ctf_new_dynsym): New.
	(lang_write_ctf): Call ldemul_new_dynsym_for_ctf with NULL to do
	the actual symbol shuffle.
	* ldlang.h (struct elf_strtab_hash): Adjust accordingly.
	* ldmain.c (bfd_link_callbacks): Wire up new/renamed callbacks.

libctf/ChangeLog
2020-10-25  Nick Alcock  <nick.alcock@oracle.com>

	* ctf-link.c (ctf_link_shuffle_syms): Adjust.
	(ctf_link_add_linker_symbol): New, unimplemented stub.
	* libctf.ver: Add it.
	* ctf-create.c (ctf_serialize): Set CTF_F_DYNSTR on newly-serialized
	dicts.
	* ctf-open-bfd.c (ctf_bfdopen_ctfsect): Check for the flag: open the
	symtab/strtab if not present, dynsym/dynstr otherwise.
	* ctf-archive.c (ctf_arc_bufpreamble): New, get the preamble from
	some arbitrary member of a CTF archive.
	* ctf-impl.h (ctf_arc_bufpreamble): Declare it.
---
 bfd/elf.c                   |  14 ++++-
 bfd/elflink.c               |  38 ++++++++++---
 binutils/readelf.c          |   4 +-
 include/bfdlink.h           |  16 ++++--
 include/ctf-api.h           |  18 +++---
 include/ctf.h               |   3 +-
 ld/emultempl/aix.em         |   3 +-
 ld/emultempl/armcoff.em     |   3 +-
 ld/emultempl/beos.em        |   3 +-
 ld/emultempl/elf-generic.em |   3 +-
 ld/emultempl/elf.em         |   3 +-
 ld/emultempl/generic.em     |   3 +-
 ld/emultempl/linux.em       |   3 +-
 ld/emultempl/msp430.em      |   3 +-
 ld/emultempl/pe.em          |   3 +-
 ld/emultempl/pep.em         |   3 +-
 ld/emultempl/ticoff.em      |   3 +-
 ld/emultempl/vanilla.em     |   3 +-
 ld/ldelfgen.c               | 110 +++++++++++++++++++-----------------
 ld/ldelfgen.h               |   9 +--
 ld/ldemul.c                 |  18 +++---
 ld/ldemul.h                 |  30 ++++++----
 ld/ldlang.c                 |  31 ++++++----
 ld/ldlang.h                 |   6 +-
 ld/ldmain.c                 |   4 +-
 libctf/ctf-archive.c        |  19 +++++++
 libctf/ctf-create.c         |   2 +
 libctf/ctf-impl.h           |   1 +
 libctf/ctf-link.c           |   9 ++-
 libctf/ctf-open-bfd.c       |  34 +++++++++--
 libctf/libctf.ver           |   2 +
 31 files changed, 271 insertions(+), 133 deletions(-)

-- 
2.29.0.249.g249b51256f

Comments

Andreas Krebbel via Binutils Nov. 17, 2020, 10:53 p.m. | #1
On Sun, Oct 25, 2020 at 02:14:05PM +0000, Nick Alcock via Binutils wrote:
> Some bits might be contentious.  The ctf_new_dynstr callback takes an

> elf_internal_sym, and this remains an elf_internal_sym right down

> through the generic emulation layers into ldelfgen.  This is no worse


Yeah, I would have preferred not needing elf/internal.h in ld, but
it's not so unreasonable in ELF specific ld files.

So, patch is OK.  I think that gets you to the point where you can
commit the patch series.

-- 
Alan Modra
Australia Development Lab, IBM
Andreas Krebbel via Binutils Nov. 18, 2020, 3:52 p.m. | #2
On 17 Nov 2020, Alan Modra told this:

> On Sun, Oct 25, 2020 at 02:14:05PM +0000, Nick Alcock via Binutils wrote:

>> Some bits might be contentious.  The ctf_new_dynstr callback takes an

>> elf_internal_sym, and this remains an elf_internal_sym right down

>> through the generic emulation layers into ldelfgen.  This is no worse

>

> Yeah, I would have preferred not needing elf/internal.h in ld, but

> it's not so unreasonable in ELF specific ld files.

>

> So, patch is OK.  I think that gets you to the point where you can

> commit the patch series.


Thank you! I'll rebase and do the usual round of retesting, then if that
passes -- which it should -- push (in the next day, probably).


Next: getting the lookup side to work better. I've been writing a lookup
testsuite and finding a lot of lookup-side bugs, mostly in places where
GCC generates CTF that is much more faithful to the original type graph
than the pre-existing DWARF converters ever did. (Not a precondition for
this series to go in: this is a strict improvement on its own.)
Andreas Krebbel via Binutils Nov. 20, 2020, 2:52 p.m. | #3
On 18 Nov 2020, Nick Alcock via Binutils verbalised:

> On 17 Nov 2020, Alan Modra told this:

>

>> On Sun, Oct 25, 2020 at 02:14:05PM +0000, Nick Alcock via Binutils wrote:

>>> Some bits might be contentious.  The ctf_new_dynstr callback takes an

>>> elf_internal_sym, and this remains an elf_internal_sym right down

>>> through the generic emulation layers into ldelfgen.  This is no worse

>>

>> Yeah, I would have preferred not needing elf/internal.h in ld, but

>> it's not so unreasonable in ELF specific ld files.

>>

>> So, patch is OK.  I think that gets you to the point where you can

>> commit the patch series.

>

> Thank you! I'll rebase and do the usual round of retesting, then if that

> passes -- which it should -- push (in the next day, probably).


Done, pushed! One last-minute bug emerged: lookups of symbols in
cross-endian builds and quite possibly emission in cross-endian links is
still broken, but then it always was broken for offsets into the ELF
strtab anyway so I consider this a separate problem to fix in another
push (the next one).

I think I can fix this with very minimal change outside libctf, perhaps
one extra function call so that the linker can tell libctf the
endianness of the target it's linking for, and another similar call in
readelf (since readelf can't just pass a bfd in to libctf which it can
use to figure out endianness).

Patch

diff --git a/bfd/elf.c b/bfd/elf.c
index 9d7cbd52e02..444bb913f1e 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -51,7 +51,8 @@  SECTION
 
 static int elf_sort_sections (const void *, const void *);
 static bfd_boolean assign_file_positions_except_relocs (bfd *, struct bfd_link_info *);
-static bfd_boolean swap_out_syms (bfd *, struct elf_strtab_hash **, int) ;
+static bfd_boolean swap_out_syms (bfd *, struct elf_strtab_hash **, int,
+				  struct bfd_link_info *);
 static bfd_boolean elf_parse_notes (bfd *abfd, char *buf, size_t size,
 				    file_ptr offset, size_t align);
 
@@ -4297,7 +4298,7 @@  _bfd_elf_compute_section_file_positions (bfd *abfd,
       /* Non-zero if doing a relocatable link.  */
       int relocatable_p = ! (abfd->flags & (EXEC_P | DYNAMIC));
 
-      if (! swap_out_syms (abfd, &strtab, relocatable_p))
+      if (! swap_out_syms (abfd, &strtab, relocatable_p, link_info))
 	return FALSE;
     }
 
@@ -8045,7 +8046,8 @@  _bfd_elf_copy_private_symbol_data (bfd *ibfd,
 static bfd_boolean
 swap_out_syms (bfd *abfd,
 	       struct elf_strtab_hash **sttp,
-	       int relocatable_p)
+	       int relocatable_p,
+	       struct bfd_link_info *info)
 {
   const struct elf_backend_data *bed;
   unsigned int symcount;
@@ -8397,6 +8399,12 @@  Unable to handle section index %x in ELF symbol.  Using ABS instead."),
       else
 	elfsym->sym.st_name = _bfd_elf_strtab_offset (stt,
 						      elfsym->sym.st_name);
+      if (info && info->callbacks->ctf_new_symbol)
+	info->callbacks->ctf_new_symbol (elfsym->dest_index,
+					 &elfsym->sym);
+
+      /* Inform the linker of the addition of this symbol.  */
+
       bed->s->swap_symbol_out (abfd, &elfsym->sym,
 			       (outbound_syms
 				+ (elfsym->dest_index
diff --git a/bfd/elflink.c b/bfd/elflink.c
index e23d189b983..cbdcc668c31 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -3779,6 +3779,11 @@  elf_finalize_dynstr (bfd *output_bfd, struct bfd_link_info *info)
   _bfd_elf_strtab_finalize (dynstr);
   size = _bfd_elf_strtab_size (dynstr);
 
+  /* Allow the linker to examine the dynsymtab now it's fully populated.  */
+
+  if (info->callbacks->examine_strtab)
+    info->callbacks->examine_strtab (dynstr);
+
   bed = get_elf_backend_data (dynobj);
   sdyn = bfd_get_linker_section (dynobj, ".dynamic");
   BFD_ASSERT (sdyn != NULL);
@@ -9840,6 +9845,7 @@  elf_link_swap_symbols_out (struct elf_final_link_info *flinfo)
 	}
     }
 
+  /* Now swap out the symbols.  */
   for (i = 0; i < hash_table->strtabcount; i++)
     {
       struct elf_sym_strtab *elfsym = &hash_table->strtab[i];
@@ -9849,6 +9855,13 @@  elf_link_swap_symbols_out (struct elf_final_link_info *flinfo)
 	elfsym->sym.st_name
 	  = (unsigned long) _bfd_elf_strtab_offset (flinfo->symstrtab,
 						    elfsym->sym.st_name);
+
+      /* Inform the linker of the addition of this symbol.  */
+
+      if (flinfo->info->callbacks->ctf_new_symbol)
+	flinfo->info->callbacks->ctf_new_symbol (elfsym->dest_index,
+						 &elfsym->sym);
+
       bed->s->swap_symbol_out (flinfo->output_bfd, &elfsym->sym,
 			       ((bfd_byte *) symbuf
 				+ (elfsym->dest_index
@@ -9857,14 +9870,6 @@  elf_link_swap_symbols_out (struct elf_final_link_info *flinfo)
 				+ elfsym->destshndx_index));
     }
 
-  /* Allow the linker to examine the strtab and symtab now they are
-     populated.  */
-
-  if (flinfo->info->callbacks->examine_strtab)
-    flinfo->info->callbacks->examine_strtab (hash_table->strtab,
-					     hash_table->strtabcount,
-					     flinfo->symstrtab);
-
   hdr = &elf_tdata (flinfo->output_bfd)->symtab_hdr;
   pos = hdr->sh_offset + hdr->sh_size;
   amt = hash_table->strtabcount * bed->s->sizeof_sym;
@@ -10472,6 +10477,12 @@  elf_link_output_extsym (struct bfd_hash_entry *bh, void *data)
 	  eoinfo->failed = TRUE;
 	  return FALSE;
 	}
+
+      /* Inform the linker of the addition of this symbol.  */
+
+      if (flinfo->info->callbacks->ctf_new_dynsym)
+	flinfo->info->callbacks->ctf_new_dynsym (h->dynindx, &sym);
+
       bed->s->swap_symbol_out (flinfo->output_bfd, &sym, esym, 0);
 
       if (flinfo->hash_sec != NULL)
@@ -12740,6 +12751,12 @@  bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
 		}
 	      sym.st_value = s->vma;
 	      dest = dynsym + dynindx * bed->s->sizeof_sym;
+
+	      /* Inform the linker of the addition of this symbol.  */
+
+	      if (info->callbacks->ctf_new_dynsym)
+		info->callbacks->ctf_new_dynsym (dynindx, &sym);
+
 	      bed->s->swap_symbol_out (abfd, &sym, dest, 0);
 	    }
 	}
@@ -12778,6 +12795,11 @@  bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
 				  + e->isym.st_value);
 		}
 
+	      /* Inform the linker of the addition of this symbol.  */
+
+	      if (info->callbacks->ctf_new_dynsym)
+		info->callbacks->ctf_new_dynsym (e->dynindx, &sym);
+
 	      dest = dynsym + e->dynindx * bed->s->sizeof_sym;
 	      bed->s->swap_symbol_out (abfd, &sym, dest, 0);
 	    }
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 9a682c3ab19..ad27f958daa 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -14654,10 +14654,10 @@  dump_section_as_ctf (Elf_Internal_Shdr * section, Filedata * filedata)
   ctfsect.cts_data = data;
 
   if (!dump_ctf_symtab_name)
-    dump_ctf_symtab_name = strdup (".symtab");
+    dump_ctf_symtab_name = strdup (".dynsym");
 
   if (!dump_ctf_strtab_name)
-    dump_ctf_strtab_name = strdup (".strtab");
+    dump_ctf_strtab_name = strdup (".dynstr");
 
   if (dump_ctf_symtab_name && dump_ctf_symtab_name[0] != 0)
     {
diff --git a/include/bfdlink.h b/include/bfdlink.h
index 55020e31f45..b92ef5408d5 100644
--- a/include/bfdlink.h
+++ b/include/bfdlink.h
@@ -671,7 +671,7 @@  struct bfd_link_info
 /* Some forward-definitions used by some callbacks.  */
 
 struct elf_strtab_hash;
-struct elf_sym_strtab;
+struct elf_internal_sym;
 
 /* This structures holds a set of callback functions.  These are called
    by the BFD linker routines.  */
@@ -795,11 +795,17 @@  struct bfd_link_callbacks
      asection * current_section, asection * previous_section,
      bfd_boolean new_segment);
   /* This callback provides a chance for callers of the BFD to examine the
-     ELF string table and symbol table once they are complete and indexes and
-     offsets assigned.  */
+     ELF (dynamic) string table once it is complete.  */
   void (*examine_strtab)
-    (struct elf_sym_strtab *syms, bfd_size_type symcount,
-     struct elf_strtab_hash *symstrtab);
+    (struct elf_strtab_hash *symstrtab);
+  /* This callback is called just before a symbol is swapped out, so that the
+     CTF machinery can look up symbols during construction.  The name is
+     already an external strtab offset at this point.  */
+  void (*ctf_new_symbol)
+    (int symidx, struct elf_internal_sym *sym);
+  /* Likewise, for dynamic symbols.  */
+  void (*ctf_new_dynsym)
+    (int symidx, struct elf_internal_sym *sym);
   /* This callback should emit the CTF section into a non-loadable section in
      the output BFD named .ctf or a name beginning with ".ctf.".  */
   void (*emit_ctf)
diff --git a/include/ctf-api.h b/include/ctf-api.h
index 38d7758a48e..93bd5f359bf 100644
--- a/include/ctf-api.h
+++ b/include/ctf-api.h
@@ -65,14 +65,20 @@  typedef struct ctf_sect
 } ctf_sect_t;
 
 /* A minimal symbol extracted from a linker's internal symbol table
-   representation.  */
+   representation.  The symbol name can be given either via st_name or via a
+   strtab offset in st_nameidx, which corresponds to one of the string offsets
+   communicated via the ctf_link_add_strtab callback.  */
 
 typedef struct ctf_link_sym
 {
-  /* The st_name will not be accessed outside the call to
-     ctf_link_shuffle_syms().  */
+  /* The st_name and st_nameidx will not be accessed outside the call to
+     ctf_link_shuffle_syms().  If you set st_nameidx to offset zero, make sure
+     to set st_nameidx_set as well.  */
 
   const char *st_name;
+  size_t st_nameidx;
+  int st_nameidx_set;
+  uint32_t st_symidx;
   uint32_t st_shndx;
   uint32_t st_type;
   uint32_t st_value;
@@ -485,10 +491,8 @@  extern int ctf_link (ctf_dict_t *, int flags);
 typedef const char *ctf_link_strtab_string_f (uint32_t *offset, void *arg);
 extern int ctf_link_add_strtab (ctf_dict_t *, ctf_link_strtab_string_f *,
 				void *);
-typedef ctf_link_sym_t *ctf_link_iter_symbol_f (ctf_link_sym_t *dest,
-						void *arg);
-extern int ctf_link_shuffle_syms (ctf_dict_t *, ctf_link_iter_symbol_f *,
-				  void *);
+extern int ctf_link_add_linker_symbol (ctf_dict_t *, ctf_link_sym_t *);
+extern int ctf_link_shuffle_syms (ctf_dict_t *);
 extern unsigned char *ctf_link_write (ctf_dict_t *, size_t *size,
 				      size_t threshold);
 
diff --git a/include/ctf.h b/include/ctf.h
index 6b8aa5315ca..d0a21f185e1 100644
--- a/include/ctf.h
+++ b/include/ctf.h
@@ -200,7 +200,8 @@  typedef struct ctf_header
 #define CTF_VERSION CTF_VERSION_3 /* Current version.  */
 
 #define CTF_F_COMPRESS	0x1		/* Data buffer is compressed by libctf.  */
-#define CTF_F_MAX	CTF_F_COMPRESS	/* The greatest flag value in use.  */
+#define CTF_F_DYNSTR 0x8		/* Strings come from .dynstr.  */
+#define CTF_F_MAX (CTF_F_COMPRESS | CTF_F_DYNSTR)
 
 typedef struct ctf_lblent
 {
diff --git a/ld/emultempl/aix.em b/ld/emultempl/aix.em
index c1fe705aa92..df7471bc490 100644
--- a/ld/emultempl/aix.em
+++ b/ld/emultempl/aix.em
@@ -1595,7 +1595,8 @@  struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation = {
   NULL,				/* new_vers_pattern */
   NULL,				/* extra_map_file_text */
   ${LDEMUL_EMIT_CTF_EARLY-NULL},
-  ${LDEMUL_EXAMINE_STRTAB_FOR_CTF-NULL},
+  ${LDEMUL_ACQUIRE_STRINGS_FOR_CTF-NULL},
+  ${LDEMUL_NEW_DYNSYM_FOR_CTF-NULL},
   gld${EMULATION_NAME}_print_symbol
 };
 EOF
diff --git a/ld/emultempl/armcoff.em b/ld/emultempl/armcoff.em
index ff22af4eb37..3a86af9ad27 100644
--- a/ld/emultempl/armcoff.em
+++ b/ld/emultempl/armcoff.em
@@ -286,7 +286,8 @@  struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   NULL,	/* new_vers_pattern */
   NULL,	/* extra_map_file_text */
   ${LDEMUL_EMIT_CTF_EARLY-NULL},
-  ${LDEMUL_EXAMINE_STRTAB_FOR_CTF-NULL},
+  ${LDEMUL_ACQUIRE_STRINGS_FOR_CTF-NULL},
+  ${LDEMUL_NEW_DYNSYM_FOR_CTF-NULL},
   ${LDEMUL_PRINT_SYMBOL-NULL}
 };
 EOF
diff --git a/ld/emultempl/beos.em b/ld/emultempl/beos.em
index ace6e3a123c..d025f21f777 100644
--- a/ld/emultempl/beos.em
+++ b/ld/emultempl/beos.em
@@ -768,7 +768,8 @@  struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   NULL,	/* new_vers_pattern */
   NULL,	/* extra_map_file_text */
   ${LDEMUL_EMIT_CTF_EARLY-NULL},
-  ${LDEMUL_EXAMINE_STRTAB_FOR_CTF-NULL},
+  ${LDEMUL_ACQUIRE_STRINGS_FOR_CTF-NULL},
+  ${LDEMUL_NEW_DYNSYM_FOR_CTF-NULL},
   ${LDEMUL_PRINT_SYMBOL-NULL}
 };
 EOF
diff --git a/ld/emultempl/elf-generic.em b/ld/emultempl/elf-generic.em
index 7e0923b20a6..a4041486577 100644
--- a/ld/emultempl/elf-generic.em
+++ b/ld/emultempl/elf-generic.em
@@ -28,4 +28,5 @@  EOF
 # Put these extra routines in ld${EMULATION_NAME}_emulation
 #
 LDEMUL_EMIT_CTF_EARLY=ldelf_emit_ctf_early
-LDEMUL_EXAMINE_STRTAB_FOR_CTF=ldelf_examine_strtab_for_ctf
+LDEMUL_ACQUIRE_STRINGS_FOR_CTF=ldelf_acquire_strings_for_ctf
+LDEMUL_NEW_DYNSYM_FOR_CTF=ldelf_new_dynsym_for_ctf
diff --git a/ld/emultempl/elf.em b/ld/emultempl/elf.em
index 59eed707ea7..cfdf60e1365 100644
--- a/ld/emultempl/elf.em
+++ b/ld/emultempl/elf.em
@@ -931,7 +931,8 @@  struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   ${LDEMUL_NEW_VERS_PATTERN-NULL},
   ${LDEMUL_EXTRA_MAP_FILE_TEXT-NULL},
   ${LDEMUL_EMIT_CTF_EARLY-NULL},
-  ${LDEMUL_EXAMINE_STRTAB_FOR_CTF-NULL},
+  ${LDEMUL_ACQUIRE_STRINGS_FOR_CTF-NULL},
+  ${LDEMUL_NEW_DYNSYM_FOR_CTF-NULL},
   ${LDEMUL_PRINT_SYMBOL-NULL}
 };
 EOF
diff --git a/ld/emultempl/generic.em b/ld/emultempl/generic.em
index 24d3c1d9c68..5a69c011b6a 100644
--- a/ld/emultempl/generic.em
+++ b/ld/emultempl/generic.em
@@ -161,7 +161,8 @@  struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   ${LDEMUL_NEW_VERS_PATTERN-NULL},
   ${LDEMUL_EXTRA_MAP_FILE_TEXT-NULL},
   ${LDEMUL_EMIT_CTF_EARLY-NULL},
-  ${LDEMUL_EXAMINE_STRTAB_FOR_CTF-NULL},
+  ${LDEMUL_ACQUIRE_STRINGS_FOR_CTF-NULL},
+  ${LDEMUL_NEW_DYNSYM_FOR_CTF-NULL},
   ${LDEMUL_PRINT_SYMBOL-NULL}
 };
 EOF
diff --git a/ld/emultempl/linux.em b/ld/emultempl/linux.em
index 14446109eae..0cff3744160 100644
--- a/ld/emultempl/linux.em
+++ b/ld/emultempl/linux.em
@@ -219,7 +219,8 @@  struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   NULL,	/* new_vers_pattern */
   NULL,	/* extra_map_file_text */
   ${LDEMUL_EMIT_CTF_EARLY-NULL},
-  ${LDEMUL_EXAMINE_STRTAB_FOR_CTF-NULL},
+  ${LDEMUL_ACQUIRE_STRINGS_FOR_CTF-NULL},
+  ${LDEMUL_NEW_DYNSYM_FOR_CTF-NULL},
   ${LDEMUL_PRINT_SYMBOL-NULL}
 };
 EOF
diff --git a/ld/emultempl/msp430.em b/ld/emultempl/msp430.em
index 7b78a53d7e1..31cba4a3978 100644
--- a/ld/emultempl/msp430.em
+++ b/ld/emultempl/msp430.em
@@ -936,7 +936,8 @@  struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   ${LDEMUL_NEW_VERS_PATTERN-NULL},
   ${LDEMUL_EXTRA_MAP_FILE_TEXT-NULL},
   ${LDEMUL_EMIT_CTF_EARLY-NULL},
-  ${LDEMUL_EXAMINE_STRTAB_FOR_CTF-NULL},
+  ${LDEMUL_ACQUIRE_STRINGS_FOR_CTF-NULL},
+  ${LDEMUL_NEW_DYNSYM_FOR_CTF-NULL},
   ${LDEMUL_PRINT_SYMBOL-NULL}
 };
 EOF
diff --git a/ld/emultempl/pe.em b/ld/emultempl/pe.em
index 00db3d0e852..e07dc9cb002 100644
--- a/ld/emultempl/pe.em
+++ b/ld/emultempl/pe.em
@@ -2415,7 +2415,8 @@  struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   NULL,	/* new_vers_pattern.  */
   NULL,	/* extra_map_file_text.  */
   ${LDEMUL_EMIT_CTF_EARLY-NULL},
-  ${LDEMUL_EXAMINE_STRTAB_FOR_CTF-NULL},
+  ${LDEMUL_ACQUIRE_STRINGS_FOR_CTF-NULL},
+  ${LDEMUL_NEW_DYNSYM_FOR_CTF-NULL},
   ${LDEMUL_PRINT_SYMBOL-NULL}
 };
 EOF
diff --git a/ld/emultempl/pep.em b/ld/emultempl/pep.em
index 2f4bdfb9fa2..74468be0ccb 100644
--- a/ld/emultempl/pep.em
+++ b/ld/emultempl/pep.em
@@ -2235,7 +2235,8 @@  struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   NULL,	/* new_vers_pattern.  */
   NULL,	/* extra_map_file_text */
   ${LDEMUL_EMIT_CTF_EARLY-NULL},
-  ${LDEMUL_EXAMINE_STRTAB_FOR_CTF-NULL},
+  ${LDEMUL_ACQUIRE_STRINGS_FOR_CTF-NULL},
+  ${LDEMUL_NEW_DYNSYM_FOR_CTF-NULL},
   ${LDEMUL_PRINT_SYMBOL-NULL}
 };
 EOF
diff --git a/ld/emultempl/ticoff.em b/ld/emultempl/ticoff.em
index 11ddd0c9bad..1cf82beb3c6 100644
--- a/ld/emultempl/ticoff.em
+++ b/ld/emultempl/ticoff.em
@@ -186,7 +186,8 @@  struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   NULL,	/* new_vers_pattern */
   NULL,  /* extra_map_file_text */
   ${LDEMUL_EMIT_CTF_EARLY-NULL},
-  ${LDEMUL_EXAMINE_STRTAB_FOR_CTF-NULL},
+  ${LDEMUL_ACQUIRE_STRINGS_FOR_CTF-NULL},
+  ${LDEMUL_NEW_DYNSYM_FOR_CTF-NULL},
   ${LDEMUL_PRINT_SYMBOL-NULL}
 };
 EOF
diff --git a/ld/emultempl/vanilla.em b/ld/emultempl/vanilla.em
index 70d193c2c79..324e38acd86 100644
--- a/ld/emultempl/vanilla.em
+++ b/ld/emultempl/vanilla.em
@@ -87,7 +87,8 @@  struct ld_emulation_xfer_struct ld_vanilla_emulation =
   NULL,	/* new_vers_pattern */
   NULL,	/* extra_map_file_text */
   NULL, /* emit_ctf_early */
-  NULL, /* examine_strtab_for_ctf */
+  NULL, /* acquire_strings_for_ctf */
+  NULL, /* new_dynsym_for_ctf */
   NULL  /* print_symbol */
 };
 EOF
diff --git a/ld/ldelfgen.c b/ld/ldelfgen.c
index e9496f918f5..ca531ee7cfe 100644
--- a/ld/ldelfgen.c
+++ b/ld/ldelfgen.c
@@ -28,6 +28,7 @@ 
 #include "ldexp.h"
 #include "ldlang.h"
 #include "elf-bfd.h"
+#include "elf/internal.h"
 #include "ldelfgen.h"
 
 void
@@ -103,11 +104,9 @@  ldelf_emit_ctf_early (void)
 /* Callbacks used to map from bfd types to libctf types, under libctf's
    control.  */
 
-struct ctf_strsym_iter_cb_arg
+struct ctf_strtab_iter_cb_arg
 {
-  struct elf_sym_strtab *syms;
-  bfd_size_type symcount;
-  struct elf_strtab_hash *symstrtab;
+  struct elf_strtab_hash *strtab;
   size_t next_i;
   size_t next_idx;
 };
@@ -121,20 +120,20 @@  ldelf_ctf_strtab_iter_cb (uint32_t *offset, void *arg_)
   bfd_size_type off;
   const char *ret;
 
-  struct ctf_strsym_iter_cb_arg *arg =
-    (struct ctf_strsym_iter_cb_arg *) arg_;
+  struct ctf_strtab_iter_cb_arg *arg =
+    (struct ctf_strtab_iter_cb_arg *) arg_;
 
   /* There is no zeroth string.  */
   if (arg->next_i == 0)
     arg->next_i = 1;
 
-  if (arg->next_i >= _bfd_elf_strtab_len (arg->symstrtab))
+  if (arg->next_i >= _bfd_elf_strtab_len (arg->strtab))
     {
       arg->next_i = 0;
       return NULL;
     }
 
-  ret = _bfd_elf_strtab_str (arg->symstrtab, arg->next_i++, &off);
+  ret = _bfd_elf_strtab_str (arg->strtab, arg->next_i++, &off);
   *offset = off;
 
   /* If we've overflowed, we cannot share any further strings: the CTF
@@ -145,69 +144,74 @@  ldelf_ctf_strtab_iter_cb (uint32_t *offset, void *arg_)
   return ret;
 }
 
-/* Return symbols from the symbol table to libctf, one by one.  We assume (and
-   assert) that the symbols in the elf_link_hash_table are in strictly ascending
-   order, and that none will be added in between existing ones.  Returns NULL
-   when iteration is complete.  */
-
-static struct ctf_link_sym *
-ldelf_ctf_symbols_iter_cb (struct ctf_link_sym *dest,
-					   void *arg_)
+void
+ldelf_acquire_strings_for_ctf
+  (struct ctf_dict *ctf_output, struct elf_strtab_hash *strtab)
 {
-  struct ctf_strsym_iter_cb_arg *arg =
-    (struct ctf_strsym_iter_cb_arg *) arg_;
+  struct ctf_strtab_iter_cb_arg args = { strtab, 0, 0 };
+  if (!ctf_output)
+    return;
 
-  if (arg->next_i > arg->symcount)
+  if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
     {
-      arg->next_i = 0;
-      arg->next_idx = 0;
-      return NULL;
+      if (ctf_link_add_strtab (ctf_output, ldelf_ctf_strtab_iter_cb,
+			       &args) < 0)
+	einfo (_("%F%P: warning: CTF strtab association failed; strings will "
+		 "not be shared: %s\n"),
+	       ctf_errmsg (ctf_errno (ctf_output)));
     }
-
-  ASSERT (arg->syms[arg->next_i].dest_index == arg->next_idx);
-  dest->st_name = _bfd_elf_strtab_str (arg->symstrtab, arg->next_i, NULL);
-  dest->st_shndx = arg->syms[arg->next_i].sym.st_shndx;
-  dest->st_type = ELF_ST_TYPE (arg->syms[arg->next_i].sym.st_info);
-  dest->st_value = arg->syms[arg->next_i].sym.st_value;
-  arg->next_i++;
-  return dest;
 }
 
 void
-ldelf_examine_strtab_for_ctf
-  (struct ctf_dict *ctf_output, struct elf_sym_strtab *syms,
-   bfd_size_type symcount, struct elf_strtab_hash *symstrtab)
+ldelf_new_dynsym_for_ctf (struct ctf_dict *ctf_output, int symidx,
+			  struct elf_internal_sym *sym)
 {
-  struct ctf_strsym_iter_cb_arg args = { syms, symcount, symstrtab,
-					  0, 0 };
-   if (!ctf_output)
+  ctf_link_sym_t lsym;
+
+  if (!ctf_output)
      return;
 
-   if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour
-       && !bfd_link_relocatable (&link_info))
+  /* New symbol.  */
+  if (sym != NULL)
     {
-      if (ctf_link_add_strtab (ctf_output, ldelf_ctf_strtab_iter_cb,
-			       &args) < 0)
-	einfo (_("%F%P: warning: CTF strtab association failed; strings will "
-		 "not be shared: %s\n"),
-	       ctf_errmsg (ctf_errno (ctf_output)));
+      lsym.st_name = NULL;
+      lsym.st_nameidx = sym->st_name;
+      lsym.st_nameidx_set = 1;
+      lsym.st_symidx = symidx;
+      lsym.st_shndx = sym->st_shndx;
+      lsym.st_type = ELF_ST_TYPE (sym->st_info);
+      lsym.st_value = sym->st_value;
+      if (ctf_link_add_linker_symbol (ctf_output, &lsym) < 0)
+	{
+	  einfo (_("%F%P: warning: CTF symbol addition failed; CTF will "
+		   "not be tied to symbols: %s\n"),
+		 ctf_errmsg (ctf_errno (ctf_output)));
+	}
+    }
+  else
+    {
+      /* Shuffle all the symbols.  */
 
-      if (ctf_link_shuffle_syms (ctf_output, ldelf_ctf_symbols_iter_cb,
-				 &args) < 0)
-	einfo (_("%F%P: warning: CTF symbol shuffling failed; slight space "
-		 "cost: %s\n"), ctf_errmsg (ctf_errno (ctf_output)));
+      if (ctf_link_shuffle_syms (ctf_output) < 0)
+	einfo (_("%F%P: warning: CTF symbol shuffling failed; CTF will "
+		 "not be tied to symbols: %s\n"),
+	       ctf_errmsg (ctf_errno (ctf_output)));
     }
 }
 #else
-extern int ldelf_emit_ctf_early (void)
+int
+ldelf_emit_ctf_early (void)
 {
   return 0;
 }
 
-extern void ldelf_examine_strtab_for_ctf
-  (struct ctf_dict *ctf_output ATTRIBUTE_UNUSED,
-   struct elf_sym_strtab *syms ATTRIBUTE_UNUSED,
-   bfd_size_type symcount ATTRIBUTE_UNUSED,
-   struct elf_strtab_hash *symstrtab ATTRIBUTE_UNUSED)
+void
+ldelf_acquire_strings_for_ctf (struct ctf_dict *ctf_output ATTRIBUTE_UNUSED,
+			       struct elf_strtab_hash *strtab ATTRIBUTE_UNUSED)
+{}
+void
+ldelf_new_dynsym_for_ctf (struct ctf_dict *ctf_output ATTRIBUTE_UNUSED,
+			  int symidx ATTRIBUTE_UNUSED,
+			  struct elf_internal_sym *sym ATTRIBUTE_UNUSED)
 {}
 #endif
diff --git a/ld/ldelfgen.h b/ld/ldelfgen.h
index 93bdf2981ba..3392c2b81a7 100644
--- a/ld/ldelfgen.h
+++ b/ld/ldelfgen.h
@@ -18,12 +18,13 @@ 
    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
    MA 02110-1301, USA.  */
 
-struct elf_sym_strtab;
+struct elf_internal_sym;
 struct elf_strtab_hash;
 struct ctf_dict;
 
 extern void ldelf_map_segments (bfd_boolean);
 extern int ldelf_emit_ctf_early (void);
-extern void ldelf_examine_strtab_for_ctf
-  (struct ctf_dict *ctf_output, struct elf_sym_strtab *syms,
-   bfd_size_type symcount, struct elf_strtab_hash *symstrtab);
+extern void ldelf_acquire_strings_for_ctf
+  (struct ctf_dict *ctf_output, struct elf_strtab_hash *strtab);
+extern void ldelf_new_dynsym_for_ctf
+  (struct ctf_dict *ctf_output, int symidx, struct elf_internal_sym *sym);
diff --git a/ld/ldemul.c b/ld/ldemul.c
index 6dc5112f7dd..920afc8d629 100644
--- a/ld/ldemul.c
+++ b/ld/ldemul.c
@@ -418,15 +418,19 @@  ldemul_emit_ctf_early (void)
 }
 
 void
-ldemul_examine_strtab_for_ctf (struct ctf_dict *ctf_output,
-			       struct elf_sym_strtab *syms,
-			       bfd_size_type symcount,
-			       struct elf_strtab_hash *symstrtab)
+ldemul_acquire_strings_for_ctf (struct ctf_dict *ctf_output,
+				struct elf_strtab_hash *symstrtab)
+{
+  if (ld_emulation->acquire_strings_for_ctf)
+    ld_emulation->acquire_strings_for_ctf (ctf_output, symstrtab);
+}
 
+void
+ldemul_new_dynsym_for_ctf (struct ctf_dict *ctf_output, int symidx,
+			   struct elf_internal_sym *sym)
 {
-  if (ld_emulation->examine_strtab_for_ctf)
-    ld_emulation->examine_strtab_for_ctf (ctf_output, syms,
-					  symcount, symstrtab);
+  if (ld_emulation->new_dynsym_for_ctf)
+    ld_emulation->new_dynsym_for_ctf (ctf_output, symidx, sym);
 }
 
 bfd_boolean
diff --git a/ld/ldemul.h b/ld/ldemul.h
index 5efe4aa3a9f..0b9653ed193 100644
--- a/ld/ldemul.h
+++ b/ld/ldemul.h
@@ -109,9 +109,11 @@  extern void ldemul_extra_map_file_text
 extern int ldemul_emit_ctf_early
   (void);
 /* Called from per-target code to examine the strtab and symtab.  */
-extern void ldemul_examine_strtab_for_ctf
-  (struct ctf_dict *, struct elf_sym_strtab *, bfd_size_type,
-   struct elf_strtab_hash *);
+extern void ldemul_acquire_strings_for_ctf
+  (struct ctf_dict *, struct elf_strtab_hash *);
+extern void ldemul_new_dynsym_for_ctf
+  (struct ctf_dict *, int symidx, struct elf_internal_sym *);
+
 extern bfd_boolean ldemul_print_symbol
   (struct bfd_link_hash_entry *hash_entry, void *ptr);
 
@@ -230,14 +232,22 @@  typedef struct ld_emulation_xfer_struct {
   int (*emit_ctf_early)
     (void);
 
-  /* Called to examine the string and symbol table late enough in linking that
-     they are finally laid out.  If emit_ctf_early returns true, this is not
-     called and ldemul_maybe_emit_ctf() emits CTF in 'early' mode: otherwise, it
-     waits until 'late'. (Late mode needs explicit support at per-target link
-     time to get called at all).  If set, called by ld when the examine_strtab
+  /* Called to examine the string table late enough in linking that it is
+     finally laid out.  If emit_ctf_early returns true, this is not called, and
+     ldemul_maybe_emit_ctf emits CTF in 'early' mode: otherwise, it waits
+     until 'late'. (Late mode needs explicit support at per-target link time to
+     get called at all).  If set, called by ld when the examine_strtab
      bfd_link_callback is invoked by per-target code.  */
-  void (*examine_strtab_for_ctf) (struct ctf_dict *, struct elf_sym_strtab *,
-				  bfd_size_type, struct elf_strtab_hash *);
+  void (*acquire_strings_for_ctf) (struct ctf_dict *, struct elf_strtab_hash *);
+
+  /* Called when a new symbol is added to the dynamic symbol table.  If
+     emit_ctf_early returns true, this is not called, and ldemul_maybe_emit_ctf
+     emits CTF in 'early' mode: otherwise, it waits until 'late'. (Late mode
+     needs explicit support at per-target link time to get called at all).  If
+     set, called by ld when the ctf_new_symbol bfd_link_callback is invoked by
+     per-target code.  Called with a NULL symbol when no further symbols will be
+     provided.  */
+  void (*new_dynsym_for_ctf) (struct ctf_dict *, int, struct elf_internal_sym *);
 
   /* Called when printing a symbol to the map file.   AIX uses this
      hook to flag gc'd symbols.  */
diff --git a/ld/ldlang.c b/ld/ldlang.c
index eaf90a63cba..b70937a1f21 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -3826,14 +3826,20 @@  lang_merge_ctf (void)
   lang_ctf_errs_warnings (ctf_output);
 }
 
-/* Let the emulation examine the symbol table and strtab to help it optimize the
-   CTF, if supported.  */
+/* Let the emulation acquire strings from the dynamic strtab to help it optimize
+   the CTF, if supported.  */
 
 void
-ldlang_ctf_apply_strsym (struct elf_sym_strtab *syms, bfd_size_type symcount,
-			 struct elf_strtab_hash *symstrtab)
+ldlang_ctf_acquire_strings (struct elf_strtab_hash *dynstrtab)
 {
-  ldemul_examine_strtab_for_ctf (ctf_output, syms, symcount, symstrtab);
+  ldemul_acquire_strings_for_ctf (ctf_output, dynstrtab);
+}
+
+/* Inform the emulation about the addition of a new dynamic symbol, in BFD
+   internal format.  */
+void ldlang_ctf_new_dynsym (int symidx, struct elf_internal_sym *sym)
+{
+  ldemul_new_dynsym_for_ctf (ctf_output, symidx, sym);
 }
 
 /* Write out the CTF section.  Called early, if the emulation isn't going to
@@ -3860,6 +3866,11 @@  lang_write_ctf (int late)
 	return;
     }
 
+  /* Inform the emulation that all the symbols that will be received have
+     been.  */
+
+  ldemul_new_dynsym_for_ctf (ctf_output, 0, NULL);
+
   /* Emit CTF.  */
 
   output_sect = bfd_get_section_by_name (link_info.output_bfd, ".ctf");
@@ -3922,11 +3933,11 @@  ldlang_open_ctf (void)
 
 static void lang_merge_ctf (void) {}
 void
-ldlang_ctf_apply_strsym (struct elf_sym_strtab *syms ATTRIBUTE_UNUSED,
-			 bfd_size_type symcount ATTRIBUTE_UNUSED,
-			 struct elf_strtab_hash *symstrtab ATTRIBUTE_UNUSED)
-{
-}
+ldlang_ctf_acquire_strings (struct elf_strtab_hash *dynstrtab
+			    ATTRIBUTE_UNUSED) {}
+void
+ldlang_ctf_new_dynsym (int symidx ATTRIBUTE_UNUSED,
+		       struct elf_internal_sym *sym ATTRIBUTE_UNUSED) {}
 static void lang_write_ctf (int late ATTRIBUTE_UNUSED) {}
 void ldlang_write_ctf_late (void) {}
 #endif
diff --git a/ld/ldlang.h b/ld/ldlang.h
index 196debfa37e..6675c57d741 100644
--- a/ld/ldlang.h
+++ b/ld/ldlang.h
@@ -689,8 +689,10 @@  extern bfd_boolean load_symbols
 
 struct elf_sym_strtab;
 struct elf_strtab_hash;
-extern void ldlang_ctf_apply_strsym
-  (struct elf_sym_strtab *, bfd_size_type, struct elf_strtab_hash *);
+extern void ldlang_ctf_acquire_strings
+  (struct elf_strtab_hash *);
+extern void ldlang_ctf_new_dynsym
+  (int symidx, struct elf_internal_sym *);
 extern void ldlang_write_ctf_late
   (void);
 extern bfd_boolean
diff --git a/ld/ldmain.c b/ld/ldmain.c
index cdb4fe58d91..082d03bfc5f 100644
--- a/ld/ldmain.c
+++ b/ld/ldmain.c
@@ -151,7 +151,9 @@  static struct bfd_link_callbacks link_callbacks =
   info_msg,
   minfo,
   ldlang_override_segment_assignment,
-  ldlang_ctf_apply_strsym,
+  ldlang_ctf_acquire_strings,
+  NULL,
+  ldlang_ctf_new_dynsym,
   ldlang_write_ctf_late
 };
 
diff --git a/libctf/ctf-archive.c b/libctf/ctf-archive.c
index 72cdef91ac4..25c30f64b50 100644
--- a/libctf/ctf-archive.c
+++ b/libctf/ctf-archive.c
@@ -377,6 +377,25 @@  ctf_new_archive_internal (int is_archive, int unmap_on_close,
   return arci;
 }
 
+/* Get the CTF preamble from data in a buffer, which may be either an archive or
+   a CTF dict.  If multiple dicts are present in an archive, the preamble comes
+   from an arbitrary dict.  The preamble is a pointer into the ctfsect passed
+   in.  */
+
+const ctf_preamble_t *
+ctf_arc_bufpreamble (const ctf_sect_t *ctfsect)
+{
+  if (ctfsect->cts_size > sizeof (uint64_t) &&
+      (le64toh ((*(uint64_t *) ctfsect->cts_data)) == CTFA_MAGIC))
+    {
+      struct ctf_archive *arc = (struct ctf_archive *) ctfsect->cts_data;
+      return (const ctf_preamble_t *) ((char *) arc + le64toh (arc->ctfa_ctfs)
+				       + sizeof (uint64_t));
+    }
+  else
+    return (const ctf_preamble_t *) ctfsect->cts_data;
+}
+
 /* Open a CTF archive or dictionary from data in a buffer (which the caller must
    preserve until ctf_arc_close() time).  Returns the archive, or NULL and an
    error in *err (if not NULL).  */
diff --git a/libctf/ctf-create.c b/libctf/ctf-create.c
index c1a7a8ac62d..384e8cfacc8 100644
--- a/libctf/ctf-create.c
+++ b/libctf/ctf-create.c
@@ -298,6 +298,8 @@  ctf_serialize (ctf_dict_t *fp)
   hdr.cth_magic = CTF_MAGIC;
   hdr.cth_version = CTF_VERSION;
 
+  hdr.cth_flags = CTF_F_DYNSTR;
+
   /* Iterate through the dynamic type definition list and compute the
      size of the CTF type section we will need to generate.  */
 
diff --git a/libctf/ctf-impl.h b/libctf/ctf-impl.h
index 3f4cfac7152..0e09a45b5bc 100644
--- a/libctf/ctf-impl.h
+++ b/libctf/ctf-impl.h
@@ -683,6 +683,7 @@  ctf_new_archive_internal (int is_archive, int unmap_on_close,
 			  const ctf_sect_t *strsect, int *errp);
 extern struct ctf_archive *ctf_arc_open_internal (const char *, int *);
 extern void ctf_arc_close_internal (struct ctf_archive *);
+extern const ctf_preamble_t *ctf_arc_bufpreamble (const ctf_sect_t *);
 extern void *ctf_set_open_errno (int *, int);
 extern unsigned long ctf_set_errno (ctf_dict_t *, int);
 
diff --git a/libctf/ctf-link.c b/libctf/ctf-link.c
index 192d4fd6622..3f4f2ee72d9 100644
--- a/libctf/ctf-link.c
+++ b/libctf/ctf-link.c
@@ -1596,9 +1596,12 @@  ctf_link_add_strtab (ctf_dict_t *fp, ctf_link_strtab_string_f *add_string,
 
 /* Not yet implemented.  */
 int
-ctf_link_shuffle_syms (ctf_dict_t *fp _libctf_unused_,
-		       ctf_link_iter_symbol_f *add_sym _libctf_unused_,
-		       void *arg _libctf_unused_)
+ctf_link_add_linker_symbol (ctf_dict_t *fp, ctf_link_sym_t *sym)
+{
+  return 0;
+}
+int
+ctf_link_shuffle_syms (ctf_dict_t *fp)
 {
   return 0;
 }
diff --git a/libctf/ctf-open-bfd.c b/libctf/ctf-open-bfd.c
index 449347ee39a..a6f0d3f6efe 100644
--- a/libctf/ctf-open-bfd.c
+++ b/libctf/ctf-open-bfd.c
@@ -100,12 +100,36 @@  ctf_bfdopen_ctfsect (struct bfd *abfd _libctf_unused_,
 
 #ifdef HAVE_BFD_ELF
   ctf_sect_t symsect, strsect;
-  Elf_Internal_Shdr *symhdr = &elf_symtab_hdr (abfd);
+  Elf_Internal_Shdr *symhdr;
   size_t symcount;
   Elf_Internal_Sym *isymbuf;
   bfd_byte *symtab = NULL;
+  const char *symtab_name;
   const char *strtab = NULL;
+  const char *strtab_name;
   size_t strsize;
+  const ctf_preamble_t *preamble;
+
+  if (ctfsect->cts_data == NULL)
+    {
+      bfderrstr = N_("CTF section is NULL");
+      goto err;
+    }
+  preamble = ctf_arc_bufpreamble (ctfsect);
+
+  if (preamble->ctp_flags & CTF_F_DYNSTR)
+    {
+      symhdr = &elf_tdata (abfd)->dynsymtab_hdr;
+      strtab_name = ".dynstr";
+      symtab_name = ".dynsym";
+    }
+  else
+    {
+      symhdr = &elf_tdata (abfd)->symtab_hdr;
+      strtab_name = ".strtab";
+      symtab_name = ".symtab";
+    }
+
   /* TODO: handle SYMTAB_SHNDX.  */
 
   /* Get the symtab, and the strtab associated with it.  */
@@ -145,12 +169,12 @@  ctf_bfdopen_ctfsect (struct bfd *abfd _libctf_unused_,
 	    strtab = (const char *) strhdr->contents;
 	}
     }
-  else		/* No symtab: just try getting .strtab by name.  */
+  else		/* No symtab: just try getting .strtab or .dynstr by name.  */
     {
       bfd_byte *str_bcontents;
       asection *str_asect;
 
-      if ((str_asect = bfd_get_section_by_name (abfd, ".strtab")) != NULL)
+      if ((str_asect = bfd_get_section_by_name (abfd, strtab_name)) != NULL)
 	{
 	  if (bfd_malloc_and_get_section (abfd, str_asect, &str_bcontents))
 	    {
@@ -168,7 +192,7 @@  ctf_bfdopen_ctfsect (struct bfd *abfd _libctf_unused_,
 	 use it for anything but debugging.  */
 
       strsect.cts_data = strtab;
-      strsect.cts_name = ".strtab";
+      strsect.cts_name = strtab_name;
       strsect.cts_size = strsize;
       strsectp = &strsect;
     }
@@ -176,7 +200,7 @@  ctf_bfdopen_ctfsect (struct bfd *abfd _libctf_unused_,
   if (symtab)
     {
       assert (symhdr->sh_entsize == get_elf_backend_data (abfd)->s->sizeof_sym);
-      symsect.cts_name = ".symtab";
+      symsect.cts_name = symtab_name;
       symsect.cts_entsize = symhdr->sh_entsize;
       symsect.cts_size = symhdr->sh_size;
       symsect.cts_data = symtab;
diff --git a/libctf/libctf.ver b/libctf/libctf.ver
index cf4fa7396b5..317913e8450 100644
--- a/libctf/libctf.ver
+++ b/libctf/libctf.ver
@@ -181,4 +181,6 @@  LIBCTF_1.1 {
 	ctf_dict_open_sections;
 	ctf_dict_close;
 	ctf_parent_dict;
+
+	ctf_link_add_linker_symbol;
 } LIBCTF_1.0;