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

[Nelson Chu <nelson@rivosinc.com>]

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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
>
>