For the lui and auipc relaxations, since the symbol value of an undefined weak
symbol is always be zero, we can optimize the patterns into a single LI/MV/ADDI
instruction.
bfd/
* elfnn-riscv.c (riscv_pcgp_hi_reloc): Add new field undefined_weak.
(riscv_record_pcgp_hi_reloc): New parameter undefined_weak.
Set undefined_weak field from it.
(relax_func_t): New parameter undefined_weak.
(_bfd_riscv_relax_call): New ignored parameter undefined_weak.
(_bfd_riscv_relax_tls_le): Likewise.
(_bfd_riscv_relax_align): Likewise.
(_bfd_riscv_relax_delete): Likewise.
(_bfd_riscv_relax_lui): New parameter undefined_weak. If true,
allow relaxing. For LO12* relocs, set rs1 to x0 when undefined_weak.
(_bfd_riscv_relax_pc): New parameter undefined_weak. For LO12* relocs,
set undefined_weak from hi_reloc. If true, allow relaxing. For LO12*
relocs, set rs1 to x0 when undefined_weak and change to non-pcrel
reloc.
(_bfd_riscv_relax_section): New local undefined_weak. Set for
undef weak relocs that can be relaxed. Pass to relax_func call.
ld/
* testsuite/ld-riscv-elf/weakref32.s: Add relaxable undef weak code.
* testsuite/ld-riscv-elf/weakref64.s: Likewise.
* testsuite/ld-riscv-elf/weakref32.d: Updated.
* testsuite/ld-riscv-elf/weakref64.d: Updated.
9d1da81b26