x86-64: Use PLT address for PC-relative reloc

Since PLT in PDE and PC-relative PLT in PIE can be used as function
address, there is no need for dynamic PC-relative relocation against
a dynamic function definition in PIE.  Linker should resolve PC-relative
reference to its PLT address.

NB: i386 has non-PIC PLT and PIC PLT.  Only non-PIC PLT in PDE can
be used as function address.  PIC PLT in PIE can't be used as
function address.

bfd/

	PR ld/22842
	* elf32-i386.c (elf_i386_check_relocs): Pass FALSE for non
	PC-relative PLT to NEED_DYNAMIC_RELOCATION_P.
	* elf64-x86-64.c (elf_x86_64_check_relocs): Create PLT for
	R_X86_64_PC32 reloc against dynamic function in data section.
	Pass TRUE for PC-relative PLT to NEED_DYNAMIC_RELOCATION_P.
	(elf_x86_64_relocate_section): Use PLT for R_X86_64_PC32 reloc
	against dynamic function in data section.
	* elfxx-x86.c (elf_x86_allocate_dynrelocs): Use PLT in PIE as
	function address only if pcrel_plt is true.
	(_bfd_x86_elf_link_hash_table_create): Set pcrel_plt.
	* elfxx-x86.h (NEED_DYNAMIC_RELOCATION_P): Add PCREL_PLT for
	PC-relative PLT.  If PLT is PC-relative, don't generate dynamic
	PC-relative relocation against a function definition in data
	secton in PIE.  Remove the obsolete comments.
	(elf_x86_link_hash_table): Add pcrel_plt.

ld/

	PR ld/22842
	* testsuite/ld-i386/i386.exp: Run PR ld/22842 tests.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-i386/pr22842a.c: New file.
	* testsuite/ld-i386/pr22842b.S: Likewise.
	* testsuite/ld-x86-64/pr22842a.c: Likewise.
	* testsuite/ld-x86-64/pr22842a.rd: Likewise.
	* testsuite/ld-x86-64/pr22842b.S: Likewise.
	* testsuite/ld-x86-64/pr22842b.rd: Likewise.

1 files changed, 16 insertions, 6 deletions

diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c
index bd36707..05d283b 100644
--- a/bfd/elfxx-x86.c
+++ b/bfd/elfxx-x86.c
@@ -179,6 +179,7 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
 	  asection *s = htab->elf.splt;
 	  asection *second_s = htab->plt_second;
 	  asection *got_s = htab->plt_got;
+	  bfd_boolean use_plt;
 
 	  /* If this is the first .plt entry, make room for the special
 	     first entry.  The .plt section is used by prelink to undo
@@ -196,12 +197,19 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
 	    }
 
 	  /* If this symbol is not defined in a regular file, and we are
-	     not generating a shared library, then set the symbol to this
-	     location in the .plt.  This is required to make function
-	     pointers compare as equal between the normal executable and
-	     the shared library.  */
-	  if (! bfd_link_dll (info)
-	      && !h->def_regular)
+	     generating PDE, then set the symbol to this location in the
+	     .plt.  This is required to make function pointers compare
+	     as equal between PDE and the shared library.
+
+	     NB: If PLT is PC-relative, we can use the .plt in PIE for
+	     function address. */
+	  if (h->def_regular)
+	    use_plt = FALSE;
+	  else if (htab->pcrel_plt)
+	    use_plt = ! bfd_link_dll (info);
+	  else
+	    use_plt = bfd_link_pde (info);
+	  if (use_plt)
 	    {
 	      if (use_plt_got)
 		{
@@ -771,6 +779,7 @@ _bfd_x86_elf_link_hash_table_create (bfd *abfd)
       ret->dt_reloc_sz = DT_RELASZ;
       ret->dt_reloc_ent = DT_RELAENT;
       ret->got_entry_size = 8;
+      ret->pcrel_plt = TRUE;
       ret->tls_get_addr = "__tls_get_addr";
     }
   if (ABI_64_P (abfd))
@@ -798,6 +807,7 @@ _bfd_x86_elf_link_hash_table_create (bfd *abfd)
 	  ret->dt_reloc_ent = DT_RELENT;
 	  ret->sizeof_reloc = sizeof (Elf32_External_Rel);
 	  ret->got_entry_size = 4;
+	  ret->pcrel_plt = FALSE;
 	  ret->pointer_r_type = R_386_32;
 	  ret->dynamic_interpreter = ELF32_DYNAMIC_INTERPRETER;
 	  ret->dynamic_interpreter_size