How to make riscv-objdump use pc-relative address rather than absolute address? And what are alias-instructions? Has a standard manual?

Question

I'm learning RISCV(64) and implementing a simulator. I compile the following simple code and disassemble the generated elf with riscv64-unknown-linux-gnu-objdump. I have two problems totally.

int main() {
  return 0;
}

1. If I use riscv64-unknown-linux-gnu-objdump -d ./xxx.elf, the asm codes are like this.

Disassembly of section .text:

0000000080000000 <_start>:
    80000000:   00000413                li      s0,0
    80000004:   00009117                auipc   sp,0x9
    80000008:   ffc10113                add     sp,sp,-4 # 80009000 <_end>
    8000000c:   00c000ef                jal     80000018 <_trm_init>

0000000080000010 <main>:
    80000010:   00000513                li      a0,0
    80000014:   00008067                ret

0000000080000018 <_trm_init>:
    80000018:   ff010113                add     sp,sp,-16
    8000001c:   00000517                auipc   a0,0x0
    80000020:   01c50513                add     a0,a0,28 # 80000038 <_etext>
    80000024:   00113423                sd      ra,8(sp)
    80000028:   fe9ff0ef                jal     80000010 <main>
    8000002c:   00050513                mv      a0,a0
    80000030:   00100073                ebreak
    80000034:   0000006f                j       80000034 <_trm_init+0x1c>

If -M no-aliases option is added, the asm codes are like this.

Disassembly of section .text:

0000000080000000 <_start>:
    80000000:   00000413                addi    s0,zero,0
    80000004:   00009117                auipc   sp,0x9
    80000008:   ffc10113                addi    sp,sp,-4 # 80009000 <_end>
    8000000c:   00c000ef                jal     ra,80000018 <_trm_init>

0000000080000010 <main>:
    80000010:   00000513                addi    a0,zero,0
    80000014:   00008067                jalr    zero,0(ra)

0000000080000018 <_trm_init>:
    80000018:   ff010113                addi    sp,sp,-16
    8000001c:   00000517                auipc   a0,0x0
    80000020:   01c50513                addi    a0,a0,28 # 80000038 <_etext>
    80000024:   00113423                sd      ra,8(sp)
    80000028:   fe9ff0ef                jal     ra,80000010 <main>
    8000002c:   00050513                addi    a0,a0,0
    80000030:   00100073                ebreak
    80000034:   0000006f                jal     zero,80000034 <_trm_init+0x1c>

Therefore, addi and add are all disassembled as add instruction. From the RISCV spec, I know li, j, ret, mv these are pseudo-instructions. But addi and add are all real instrucions, why are they all translated into add? Is alias-instruction different with pseudo-instruction? Is there a standard manual about this alias-instruction? Even if it is tool-related, I want to see the accurate statements.

2. See the second piece of asm codes above, the immediate address offset of jal instrcution(like jal ra,80000018) is absolute address rather than pc-relative address. So How to make riscv-objdump use pc-relative address rather than absolute address?

My Environment:
Machine: x86_64
OS: Ubuntu 22.04(VMWare Virtual Machine)
riscv64-unknown-linux-gnu-objdump -v: GNU objdump (GNU Binutils) 2.40.0.20230214

Thanks in advance!