[PATCH v2 1/1] aarch64: mingw: Auto-import implementation

[Jan Beulich]

On 31.07.2026 16:46, Evgeny Karpov wrote:
> --- a/ld/emultempl/pep.em
> +++ b/ld/emultempl/pep.em
> @@ -1160,10 +1160,22 @@ pep_fixup_stdcalls (void)
>  static bfd_vma
>  read_addend (arelent *rel, asection *s)
>  {
> -  char buf[8];
>    bfd_vma addend = 0;
>    bool ok = false;
>  
> +#if defined (COFF_WITH_peAArch64)
> +  switch (rel->howto->bitsize)
> +    {
> +    case 12:
> +    case 21:
> +    case 26:
> +      ok = true;
> +      break;
> +    }
> +
> +#else
> +  char buf[8];
> +
>    switch (rel->howto->bitsize)
>      {
>      case 8:
> @@ -1186,7 +1198,6 @@ read_addend (arelent *rel, asection *s)
>  	    addend = bfd_get_16 (s->owner, buf);
>  	}
>        break;
> -    case 26:

How come this can go away here?

Apart from this question only a few mechanical comments; the bulk of this
wants looking at by Arm64 folks.

> --- a/ld/pe-dll.c
> +++ b/ld/pe-dll.c
> @@ -2842,10 +2842,181 @@ pe_create_runtime_relocator_reference (bfd *parent)
>    return abfd;
>  }
>  
> +static void
> +aarch64_make_jump_stub(const char* symbol_name, bfd* parent)
> +{
> +  static struct bfd_hash_table *stub_hash = NULL;
> +  if (!stub_hash)
> +    {
> +      stub_hash = (struct bfd_hash_table *) xmalloc
> +		  (sizeof (struct bfd_hash_table));
> +      bfd_hash_table_init (stub_hash, bfd_hash_newfunc,
> +			  sizeof (struct bfd_hash_entry));
> +    }
> +
> +  if (pe_dll_extra_pe_debug)
> +    printf ("validate jump stub for %s\n", symbol_name);
> +
> +  if (bfd_hash_lookup(stub_hash, symbol_name, false, false))
> +    return;
> +
> +  if (pe_dll_extra_pe_debug)
> +    printf ("creating jump stub for %s\n", symbol_name);
> +  bfd_hash_lookup(stub_hash, symbol_name, true, true);
> +
> +  static unsigned tmp_stub_seq = 0;
> +  char *oname = xasprintf ("jump_stub_d%06d.o", tmp_stub_seq);
> +  ++tmp_stub_seq;
> +
> +  bfd *abfd = bfd_create (oname, parent);
> +  free (oname);
> +  bfd_make_writable (abfd);
> +
> +  bfd_set_format (abfd, bfd_object);
> +  bfd_set_arch_mach (abfd, pe_details->bfd_arch, 0);
> +
> +  symptr = 0;
> +  symtab = xmalloc (12 * sizeof (asymbol *));
> +
> +  asection *tx  = quick_section (abfd, ".text", SEC_CODE | SEC_HAS_CONTENTS
> +				 | SEC_READONLY, 2);
> +  quick_symbol (abfd, "", symbol_name, "", tx, BSF_GLOBAL, 0);
> +  quick_symbol (abfd, "__imp_", symbol_name, "", bfd_und_section_ptr,
> +		BSF_GLOBAL, 0);
> +
> +  const unsigned jmp_byte_count = sizeof (jmp_aarch64_bytes);
> +  bfd_set_section_size (tx, jmp_byte_count);
> +  unsigned char *td = xmalloc (jmp_byte_count);
> +  tx->contents = td;
> +  memcpy (td, jmp_aarch64_bytes, jmp_byte_count);
> +
> +  quick_reloc (abfd, 0, BFD_RELOC_AARCH64_ADR_HI21_NC_PCREL, 2);
> +  quick_reloc (abfd, 4, BFD_RELOC_AARCH64_ADD_LO12, 2);
> +  save_relocs (tx);
> +
> +  bfd_set_symtab (abfd, symtab, symptr);
> +
> +  bfd_set_section_contents (abfd, tx, td, 0, jmp_byte_count);
> +  bfd_make_readable (abfd);
> +  add_bfd_to_link (abfd, bfd_get_filename (abfd), &link_info);
> +}
> +
> +static void
> +aarch64_make_imp_offset(const char* imp_symbol_name,
> +			const char* imp_offset_name, const int offset,
> +			unsigned rd, const char* caller_label, bfd* parent)
> +{
> +  if (pe_dll_extra_pe_debug)
> +    printf("symbol: %s imp_offset_name: %s offset: %u rs: %u caller: %s\n",
> +	   imp_symbol_name, imp_offset_name, offset, rd, caller_label);
> +
> +  static const unsigned char imp_offset_bytes[] =
> +    {
> +      0x00, 0x00, 0x00, 0x90, /* adrp x0, <imp_symbol_name>		*/
> +      0x00, 0x00, 0x40, 0xf9, /* ldr x0, [x0, :lo12:<imp_symbol_name>]	*/
> +      0x00, 0x00, 0x40, 0x91, /* add x0, x0, 0, lsl 12			*/
> +      0x01, 0x00, 0x00, 0x14  /* b <caller_label> + 4			*/
> +    };
> +
> +  static unsigned tmp_stub_seq = 0;
> +  char *oname = xasprintf ("imp_offset_stub_d%06d.o", tmp_stub_seq);
> +  ++tmp_stub_seq;
> +
> +  bfd *abfd = bfd_create (oname, parent);
> +  free (oname);
> +  bfd_make_writable (abfd);
> +
> +  bfd_set_format (abfd, bfd_object);
> +  bfd_set_arch_mach (abfd, pe_details->bfd_arch, 0);
> +
> +  symptr = 0;
> +  symtab = xmalloc (12 * sizeof (asymbol *));
> +
> +  asection *tx = quick_section (abfd, ".text", SEC_CODE | SEC_HAS_CONTENTS
> +				| SEC_READONLY, 2);
> +  quick_symbol (abfd, "", imp_offset_name, "", tx, BSF_GLOBAL, 0);
> +  quick_symbol (abfd, "", imp_symbol_name, "", UNDSEC, BSF_GLOBAL, 0);
> +  quick_symbol (abfd, "", caller_label, "", UNDSEC, BSF_GLOBAL, 0);
> +
> +  const unsigned imp_offset_byte_count = sizeof (imp_offset_bytes);
> +  bfd_set_section_size (tx, imp_offset_byte_count);
> +  uint32_t *td = xmalloc (imp_offset_byte_count);
> +  tx->contents = (bfd_byte*) td;
> +  memcpy (td, imp_offset_bytes, imp_offset_byte_count);
> +
> +  rd &= (1 << 5) - 1;
> +  td[0] |= rd;
> +  td[1] |= (rd << 5) | rd;
> +
> +  unsigned imm = 0;
> +  if (offset >= 0)
> +    imm = offset;
> +  else
> +  {
> +    imm = -offset + 4096;
> +/* Change "add x0, x0, 0, lsl 12" to "sub x0, x0, 0, lsl 12".  */

The comment wants indenting.

> +    td[2] |= 1 << 30;
> +  }
> +  imm >>= 12;
> +  imm &= ((1 << 12) - 1);
> +  td[2] |= (rd << 5) | rd;
> +  td[2] |= imm << 10;
> +
> +  quick_reloc (abfd, 0, BFD_RELOC_AARCH64_ADR_HI21_PCREL, 2);
> +  quick_reloc (abfd, 4, BFD_RELOC_AARCH64_LDST64_LO12, 2);
> +  quick_reloc (abfd, 12, BFD_RELOC_AARCH64_CALL26, 3);
> +  save_relocs (tx);
> +
> +  bfd_set_symtab (abfd, symtab, symptr);
> +
> +  bfd_set_section_contents (abfd, tx, td, 0, imp_offset_byte_count);
> +  bfd_make_readable (abfd);
> +  add_bfd_to_link (abfd, bfd_get_filename (abfd), &link_info);
> +}
> +
>  void
>  pe_create_import_fixup (arelent *rel, asection *s, bfd_vma addend, char *name,
>  			const char *symname)
>  {
> + if (pe_details->pe_arch == PE_ARCH_aarch64)
> +   {

There looks to be an indentation issue on these two lines.

> +      if (rel->howto->bitsize == 12)
> +	return;
> +      else if (rel->howto->bitsize == 26)
> +	{
> +/* On AArch64, a single opcode is not sufficient for relocation
> +   in dynamic linking. The linker generates a jump stub instead.  */

Missing indentation again.

Jan