[V3 18/36] [SFrame-V3] gas: sframe: output new FDE type SFRAME_FDE_TYPE_FLEX

[Jens Remus]

On 1/13/2026 12:12 PM, Indu Bhagat wrote:
> This patch updates the routines for emission of the new FDE type
> SFRAME_FDE_TYPE_FLEX in the SFrame output section.  The support for
> generating these flex FDEs themselves is added in a subsequent commit.
> 
> Update struct sframe_row_entry to track additional state for CFA,
> FP, and RA.  Modify output_sframe_row_entry_offsets () to emit
> metadata/offset pairs for flexible FDEs or padding where applicable,
> ensuring the usual ordering (CFA, RA, FP).  The padding data, a.k.a.
> SFRAME_FRE_RA_OFFSET_INVALID is emitted in flexible FDEs when RA is
> untracked but FP offsets follow.  Trailing padding offsets should not
> occur.  Add a new function get_udata_size_in_bytes () to account for
> sizing of unsigned register metadata.

> diff --git a/gas/gen-sframe.c b/gas/gen-sframe.c


> @@ -420,6 +454,38 @@ sframe_get_fre_offset_size (const struct sframe_row_entry *sframe_fre)
>    if (ra_offset_size > max_offset_size)
>      max_offset_size = ra_offset_size;
>  
> +  /* If flex FDE, account for reg data too.  */
> +  if (flex_p)
> +    {
> +      bool reg_p = (sframe_fre->cfa_base_reg != SFRAME_FRE_REG_INVALID);
> +      unsigned int data
> +	= SFRAME_V3_FLEX_FDE_REG_ENCODE (sframe_fre->cfa_base_reg,
> +					 sframe_fre->cfa_deref_p, reg_p);
> +      unsigned int data_size = get_udata_size_in_bytes (data);
> +      if (data_size > max_offset_size)
> +	max_offset_size = data_size;
> +
> +      if (sframe_fre->ra_loc != SFRAME_FRE_ELEM_LOC_NONE)
> +	{
> +	  reg_p = (sframe_fre->ra_loc != SFRAME_FRE_ELEM_LOC_REG);

Mustn't that be as follows (like it is done for FP below)?

	  reg_p = (sframe_fre->ra_loc == SFRAME_FRE_ELEM_LOC_REG);

> +	  data = SFRAME_V3_FLEX_FDE_REG_ENCODE (sframe_fre->ra_reg,
> +						sframe_fre->ra_deref_p, reg_p);
> +	  data_size = get_udata_size_in_bytes (data);
> +	  if (data_size > max_offset_size)
> +	    max_offset_size = data_size;
> +	}
> +
> +      if (sframe_fre->fp_loc != SFRAME_FRE_ELEM_LOC_NONE)
> +	{
> +	  reg_p = (sframe_fre->fp_loc == SFRAME_FRE_ELEM_LOC_REG);
> +	  data = SFRAME_V3_FLEX_FDE_REG_ENCODE (sframe_fre->fp_reg,
> +						sframe_fre->fp_deref_p, reg_p);
> +	  data_size = get_udata_size_in_bytes (data);
> +	  if (data_size > max_offset_size)
> +	    max_offset_size = data_size;
> +	}
> +    }
> +
>    gas_assert (max_offset_size);
>  
>    switch (max_offset_size)
Regards,
Jens
-- 
Jens Remus
Linux on Z Development (D3303)
jremus@de.ibm.com / jremus@linux.ibm.com

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