Don't generate PLT for IFUNC GOT/pointer reference

Don't generate PLT for IFUNC GOT/pointer reference

If a backend supports it, PLT entry isn't needed when all references
to a STT_GNU_IFUNC symbols are done via GOT or static function pointers.
For GOT entries, We generate dynamic R_*_GLOB_DAT relocations for
preemptable symbols and R_*_IRELATIVE relocations for non-preemptable
symbols to update them with real function address.  For static pointer
pointers, we generate dynamic pointer relocations and store them in:

1. .rel[a].ifunc section in PIC object.
2. .rel[a].got section in dynamic executable.
3. .rel[a].iplt section in static executable.

We don't allocate GOT entry if it isn't used.

bfd/

	PR ld/20253
	* elf-bfd.h (_bfd_elf_allocate_ifunc_dyn_relocs): Add an
	bfd_boolean argument.
	* elf-ifunc.c (_bfd_elf_create_ifunc_sections): Replace
	"shared object" with "PIC object" in comments.
	(_bfd_elf_allocate_ifunc_dyn_relocs): Updated.  Replace
	"shared object" with "PIC object" in comments.  Avoid PLT if
	requested.  Generate dynamic relocations for non-GOT references.
	Make room for the special first entry in PLT and allocate PLT
	entry only for PLT and PC-relative references.  Store dynamic
	GOT relocations in .rel[a].iplt section for static executables.
	If PLT isn't used, always use GOT for symbol value.  Don't
	allocate GOT entry if it isn't used.
	* elf32-i386.c (elf_i386_check_relocs): Increment PLT reference
	count only in the code section.  Allocate dynamic pointer
	relocation against STT_GNU_IFUNC symbol in the non-code section.
	(elf_i386_adjust_dynamic_symbol): Increment PLT reference count
	only for PC-relative references.
	(elf_i386_allocate_dynrelocs): Pass TRUE to
	_bfd_elf_allocate_ifunc_dyn_relocs.
	(elf_i386_relocate_section): Allow R_386_GOT32/R_386_GOT32X
	relocations against STT_GNU_IFUNC symbols without PLT.  Generate
	dynamic pointer relocation against STT_GNU_IFUNC symbol in
	the non-code section and store it in the proper REL section.
	Don't allow non-pointer relocation against STT_GNU_IFUNC symbol
	without PLT.
	(elf_i386_finish_dynamic_symbol): Generate dynamic
	R_386_IRELATIVE and R_386_GLOB_DAT GOT relocations against
	STT_GNU_IFUNC symbols without PLT.
	(elf_i386_finish_dynamic_sections): Don't handle local
	STT_GNU_IFUNC symbols here.
	(elf_i386_output_arch_local_syms): Handle local STT_GNU_IFUNC
	symbols here.
	(elf_backend_output_arch_local_syms): New.
	* elf32-x86-64.c (elf_i386_check_relocs): Increment PLT reference
	count only in the code section.  Allocate dynamic pointer
	relocation against STT_GNU_IFUNC symbol in the non-code section.
	(elf_x86_64_adjust_dynamic_symbol): Increment PLT reference
	count only for PC-relative references.
	(elf_x86_64_allocate_dynrelocs): Pass TRUE to
	_bfd_elf_allocate_ifunc_dyn_relocs.
	(elf_x86_64_relocate_section): Allow R_X86_64_GOTPCREL,
	R_X86_64_GOTPCRELX, R_X86_64_REX_GOTPCRELX and
	R_X86_64_GOTPCREL64 relocations against STT_GNU_IFUNC symbols
	without PLT.  Generate dynamic pointer relocation against
	STT_GNU_IFUNC symbol in the non-code section and store it in
	the proper RELA section.  Don't allow non-pointer relocation
	against STT_GNU_IFUNC symbol without PLT.
	(elf_x86_64_finish_dynamic_symbol): Generate dynamic
	R_X86_64_IRELATIVE and R_X86_64_GLOB_DAT GOT relocations against
	STT_GNU_IFUNC symbols without PLT.
	(elf_x86_64_finish_dynamic_sections): Don't handle local
	STT_GNU_IFUNC symbols here.
	(elf_x86_64_output_arch_local_syms): Handle local STT_GNU_IFUNC
	symbols here.
	(elf_backend_output_arch_local_syms): New.
	* elfnn-aarch64.c (elfNN_aarch64_allocate_ifunc_dynrelocs):
	Pass FALSE to _bfd_elf_allocate_ifunc_dyn_relocs.

ld/

	PR ld/20253
	* testsuite/ld-i386/i386.exp: Run PR ld/20253 tests.
	* testsuite/ld-i386/no-plt.exp: Likewise.
	* testsuite/ld-x86-64/no-plt.exp: Likewise.
	* testsuite/ld-i386/pr13302.d: Remove .rel.plt section.
	* testsuite/ld-ifunc/ifunc-13-i386.d: Likewise.
	* testsuite/ld-ifunc/ifunc-13-x86-64.d: Likewise.
	* testsuite/ld-ifunc/ifunc-15-i386.d: Likewise.
	* testsuite/ld-ifunc/ifunc-15-x86-64.d: Likewise.
	* testsuite/ld-x86-64/pr13082-5a.d: Likewise.
	* testsuite/ld-x86-64/pr13082-5b.d: Likewise.
	* testsuite/ld-x86-64/pr13082-6a.d: Likewise.
	* testsuite/ld-x86-64/pr13082-6b.d: Likewise.
	* testsuite/ld-i386/pr20244-2a.d: Remove .plt section.
	* testsuite/ld-ifunc/ifunc-21-i386.d: Likewise.
	* testsuite/ld-ifunc/ifunc-21-x86-64.d: Likewise.
	* testsuite/ld-ifunc/ifunc-22-i386.d: Likewise.
	* testsuite/ld-ifunc/ifunc-22-x86-64.d: Likewise.
	* testsuite/ld-i386/pr20244-2b.d: Updated.
	* testsuite/ld-i386/pr20244-2c.d: Likewise.
	* testsuite/ld-ifunc/ifunc-18a-i386.d: Likewise.
	* testsuite/ld-ifunc/ifunc-18a-x86-64.d: Likewise.
	* testsuite/ld-ifunc/ifunc-18b-i386.d: Likewise.
	* testsuite/ld-ifunc/ifunc-18b-x86-64.d: Likewise.
	* testsuite/ld-i386/pr20253-1a.c: New file.
	* testsuite/ld-i386/pr20253-1b.S: Likewise.
	* testsuite/ld-i386/pr20253-1c.S: Likewise.
	* testsuite/ld-i386/pr20253-1d.S: Likewise.
	* testsuite/ld-i386/pr20253-2a.c: Likewise.
	* testsuite/ld-i386/pr20253-2b.S: Likewise.
	* testsuite/ld-i386/pr20253-2c.S: Likewise.
	* testsuite/ld-i386/pr20253-2d.S: Likewise.
	* testsuite/ld-i386/pr20253-3.d: Likewise.
	* testsuite/ld-i386/pr20253-3.s: Likewise.
	* testsuite/ld-i386/pr20253-4.s: Likewise.
	* testsuite/ld-i386/pr20253-4a.d: Likewise.
	* testsuite/ld-i386/pr20253-4b.d: Likewise.
	* testsuite/ld-i386/pr20253-4c.d: Likewise.
	* testsuite/ld-i386/pr20253-5.d: Likewise.
	* testsuite/ld-i386/pr20253-5.s: Likewise.
	* testsuite/ld-ifunc/ifunc-23-x86.s: Likewise.
	* testsuite/ld-ifunc/ifunc-23a-x86.d: Likewise.
	* testsuite/ld-ifunc/ifunc-23b-x86.d: Likewise.
	* testsuite/ld-ifunc/ifunc-23c-x86.d: Likewise.
	* testsuite/ld-ifunc/ifunc-24-x86.s: Likewise.
	* testsuite/ld-ifunc/ifunc-24a-x86.d: Likewise.
	* testsuite/ld-ifunc/ifunc-24b-x86.d: Likewise.
	* testsuite/ld-ifunc/ifunc-24c-x86.d: Likewise.
	* testsuite/ld-ifunc/ifunc-25-x86.s: Likewise.
	* testsuite/ld-ifunc/ifunc-25a-x86.d: Likewise.
	* testsuite/ld-ifunc/ifunc-25b-x86.d: Likewise.
	* testsuite/ld-ifunc/ifunc-25c-x86.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1.s: Likewise.
	* testsuite/ld-x86-64/pr20253-1a.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1b.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1c.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1d.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1e.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1f.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1g.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1h.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1i.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1j.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1k.d: Likewise.
	* testsuite/ld-x86-64/pr20253-1l.d: Likewise.
	* testsuite/ld-x86-64/pr20253-2a.c: Likewise.
	* testsuite/ld-x86-64/pr20253-2b.S: Likewise.
	* testsuite/ld-x86-64/pr20253-2c.S: Likewise.
	* testsuite/ld-x86-64/pr20253-2d.S: Likewise.
	* testsuite/ld-x86-64/pr20253-3.d: Likewise.
	* testsuite/ld-x86-64/pr20253-3.s: Likewise.
	* testsuite/ld-x86-64/pr20253-4.s: Likewise.
	* testsuite/ld-x86-64/pr20253-4a.d: Likewise.
	* testsuite/ld-x86-64/pr20253-4b.d: Likewise.
	* testsuite/ld-x86-64/pr20253-4c.d: Likewise.
	* testsuite/ld-x86-64/pr20253-4d.d: Likewise.
	* testsuite/ld-x86-64/pr20253-4e.d: Likewise.
	* testsuite/ld-x86-64/pr20253-4f.d: Likewise.
	* testsuite/ld-x86-64/pr20253-5.s: Likewise.
	* testsuite/ld-x86-64/pr20253-5a.d: Likewise.
	* testsuite/ld-x86-64/pr20253-5b.d: Likewise.
	* testsuite/ld-ifunc/ifunc-18a-i386.d: Remove extra IRELATIVE
	relocation.
	* testsuite/ld-ifunc/ifunc-18a-x86-64.d: Likewise.
	* testsuite/ld-ifunc/ifunc-18b-i386.d: Likewise.
	* testsuite/ld-ifunc/ifunc-18b-x86-64.d: Likewise.
	* testsuite/ld-ifunc/ifunc-18a.s: Fix a typo.
	* testsuite/ld-x86-64/x86-64.exp: Run pr20253-1 tests.