[PATCH v2] RISC-V: emit R_RISCV_RELAX for the la pseudo instruction

[Rui Ueyama]

Thank you for reviewing! I'll let you know when you can merge this
patch (i.e. when my proposal is ratified.)

Meanwhile, do I need to fill in the copyright assignment form?


On Thu, Sep 21, 2023 at 9:19 AM Nelson Chu <nelson@rivosinc.com> wrote:
>
> Looks good, thanks!
>
> Nelson
>
> On Wed, Sep 20, 2023 at 4:34 PM Rui Ueyama <rui314@gmail.com> wrote:
>>
>> Now the macro identifier is stored to tc_fix_data if a relocation
>> is created as a result of assembler macro expansion.
>>
>>
>> ---
>>  gas/config/tc-riscv.c                 | 15 +++++++++++++++
>>  gas/config/tc-riscv.h                 |  8 ++++++++
>>  gas/testsuite/gas/riscv/la-variants.d |  3 +++
>>  3 files changed, 26 insertions(+)
>>
>> diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
>> index 3b520ad208b..c761b793afc 100644
>> --- a/gas/config/tc-riscv.c
>> +++ b/gas/config/tc-riscv.c
>> @@ -59,6 +59,9 @@ struct riscv_cl_insn
>>    fixS *fixp;
>>  };
>>
>> +/* The identifier of the assembler macro we are expanding, if any. */
>> +static int source_macro = -1;
>> +
>>  /* All RISC-V CSR belong to one of these classes.  */
>>  enum riscv_csr_class
>>  {
>> @@ -1659,6 +1662,7 @@ append_insn (struct riscv_cl_insn *ip, expressionS *address_expr,
>>                                   address_expr, false, reloc_type);
>>
>>           ip->fixp->fx_tcbit = riscv_opts.relax;
>> +         ip->fixp->tc_fix_data.source_macro = source_macro;
>>         }
>>      }
>>
>> @@ -2020,6 +2024,8 @@ macro (struct riscv_cl_insn *ip, expressionS *imm_expr,
>>    int rs2 = (ip->insn_opcode >> OP_SH_RS2) & OP_MASK_RS2;
>>    int mask = ip->insn_mo->mask;
>>
>> +  source_macro = mask;
>> +
>>    switch (mask)
>>      {
>>      case M_LI:
>> @@ -2168,6 +2174,8 @@ macro (struct riscv_cl_insn *ip, expressionS *imm_expr,
>>        as_bad (_("internal: macro %s not implemented"), ip->insn_mo->name);
>>        break;
>>      }
>> +
>> +  source_macro = -1;
>>  }
>>
>>  static const struct percent_op_match percent_op_utype[] =
>> @@ -4049,6 +4057,13 @@ md_apply_fix (fixS *fixP, valueT *valP, segT seg ATTRIBUTE_UNUSED)
>>        break;
>>
>>      case BFD_RELOC_RISCV_GOT_HI20:
>> +      /* R_RISCV_GOT_HI20 and the following R_RISCV_LO12_I are relaxable
>> +        only if it is created as a result of la or lga assembler macros. */
>> +      if (fixP->tc_fix_data.source_macro == M_LA ||
>> +         fixP->tc_fix_data.source_macro == M_LGA)
>> +       relaxable = true;
>> +      break;
>> +
>>      case BFD_RELOC_RISCV_ADD8:
>>      case BFD_RELOC_RISCV_ADD16:
>>      case BFD_RELOC_RISCV_ADD32:
>> diff --git a/gas/config/tc-riscv.h b/gas/config/tc-riscv.h
>> index 0c70c7d4739..4fba3a07829 100644
>> --- a/gas/config/tc-riscv.h
>> +++ b/gas/config/tc-riscv.h
>> @@ -101,6 +101,14 @@ extern void riscv_pre_output_hook (void);
>>  #define TC_FORCE_RELOCATION_LOCAL(FIX) 1
>>  #define DIFF_EXPR_OK 1
>>
>> +struct riscv_fix
>> +{
>> +  int source_macro;
>> +};
>> +
>> +#define TC_FIX_TYPE struct riscv_fix
>> +#define TC_INIT_FIX_DATA(FIX) (FIX)->tc_fix_data.source_macro = -1
>> +
>>  extern void riscv_pop_insert (void);
>>  #define md_pop_insert()                riscv_pop_insert ()
>>
>> diff --git a/gas/testsuite/gas/riscv/la-variants.d b/gas/testsuite/gas/riscv/la-variants.d
>> index b1d316983b7..e8ac09c2af2 100644
>> --- a/gas/testsuite/gas/riscv/la-variants.d
>> +++ b/gas/testsuite/gas/riscv/la-variants.d
>> @@ -21,11 +21,13 @@ Disassembly of section .text:
>>  [      ]+[0-9a-f]+:[   ]+R_RISCV_RELAX[        ]+\*ABS\*
>>  [      ]+[0-9a-f]+:[   ]+00000617[     ]+auipc[        ]+a2,0x0
>>  [      ]+[0-9a-f]+:[   ]+R_RISCV_GOT_HI20[     ]+a
>> +[      ]+[0-9a-f]+:[   ]+R_RISCV_RELAX[        ]+\*ABS\*
>>  [      ]+[0-9a-f]+:[   ]+(00062603|00063603)[  ]+(lw|ld)[      ]+a2,0\(a2\).*
>>  [      ]+[0-9a-f]+:[   ]+R_RISCV_PCREL_LO12_I[         ]+\.L0[ ]+
>>  [      ]+[0-9a-f]+:[   ]+R_RISCV_RELAX[        ]+\*ABS\*
>>  [      ]+[0-9a-f]+:[   ]+00000697[     ]+auipc[        ]+a3,0x0
>>  [      ]+[0-9a-f]+:[   ]+R_RISCV_GOT_HI20[     ]+a
>> +[      ]+[0-9a-f]+:[   ]+R_RISCV_RELAX[        ]+\*ABS\*
>>  [      ]+[0-9a-f]+:[   ]+(0006a683|0006b683)[  ]+(lw|ld)[      ]+a3,0\(a3\).*
>>  [      ]+[0-9a-f]+:[   ]+R_RISCV_PCREL_LO12_I[         ]+\.L0[ ]+
>>  [      ]+[0-9a-f]+:[   ]+R_RISCV_RELAX[        ]+\*ABS\*
>> @@ -37,6 +39,7 @@ Disassembly of section .text:
>>  [      ]+[0-9a-f]+:[   ]+R_RISCV_RELAX[        ]+\*ABS\*
>>  [      ]+[0-9a-f]+:[   ]+00000797[     ]+auipc[        ]+a5,0x0
>>  [      ]+[0-9a-f]+:[   ]+R_RISCV_GOT_HI20[     ]+a
>> +[      ]+[0-9a-f]+:[   ]+R_RISCV_RELAX[        ]+\*ABS\*
>>  [      ]+[0-9a-f]+:[   ]+(0007a783|0007b783)[  ]+(lw|ld)[      ]+a5,0\(a5\).*
>>  [      ]+[0-9a-f]+:[   ]+R_RISCV_PCREL_LO12_I[         ]+\.L0[ ]+
>>  [      ]+[0-9a-f]+:[   ]+R_RISCV_RELAX[        ]+\*ABS\*
>> --
>> 2.34.1
>>