be accompanied by major changes to make use of that data.
In any event, we can tell that we are expanding from a single-slot
- three-byte format to a wider one with the logic below. */
+ format to a wider one with the logic below. */
- if (fmt_size <= 3 && fragP->tc_frag_data.text_expansion[0] != 3)
- return 3 + fragP->tc_frag_data.text_expansion[0];
- else
- return 3;
+ int i;
+ int relaxed_size = fmt_size + fragP->tc_frag_data.text_expansion[0];
+
+ for (i = 0; i < xtensa_isa_num_formats (isa); i++)
+ {
+ if (relaxed_size == xtensa_format_length (isa, i))
+ return relaxed_size;
+ }
+
+ return 3;
}
if (fragP->tc_frag_data.slot_subtypes[0] == RELAX_NARROW)
{
if (target_size <= 4)
return 2;
- gas_assert (target_size == 8);
- return 3;
+
+ if (target_size <= 8)
+ return 3;
+
+ if (target_size <= 16)
+ return 4;
+
+ if (target_size <= 32)
+ return 5;
+
+ if (target_size <= 64)
+ return 6;
+
+ if (target_size <= 128)
+ return 7;
+
+ if (target_size <= 256)
+ return 8;
+
+ if (target_size <= 512)
+ return 9;
+
+ if (target_size <= 1024)
+ return 10;
+
+ gas_assert (0);
+ return 0;
}
static int
branch_align_power (segT sec)
{
- /* If the Xtensa processor has a fetch width of 8 bytes, and the section
- is aligned to at least an 8-byte boundary, then a branch target need
- only fit within an 8-byte aligned block of memory to avoid a stall.
- Otherwise, try to fit branch targets within 4-byte aligned blocks
- (which may be insufficient, e.g., if the section has no alignment, but
- it's good enough). */
- if (xtensa_fetch_width == 8)
- {
- if (get_recorded_alignment (sec) >= 3)
- return 3;
- }
- else
- gas_assert (xtensa_fetch_width == 4);
+ /* If the Xtensa processor has a fetch width of X, and
+ the section is aligned to at least that boundary, then a branch
+ target need only fit within that aligned block of memory to avoid
+ a stall. Otherwise, try to fit branch targets within 4-byte
+ aligned blocks (which may be insufficient, e.g., if the section
+ has no alignment, but it's good enough). */
+ int fetch_align = get_text_align_power(xtensa_fetch_width);
+ int sec_align = get_recorded_alignment (sec);
+
+ if (sec_align >= fetch_align)
+ return fetch_align;
return 2;
}
/* The idea: widen everything you can to get a target or loop aligned,
then start using NOPs.
- When we must have a NOP, here is a table of how we decide
- (so you don't have to fight through the control flow below):
-
wide_nops = the number of wide NOPs available for aligning
narrow_nops = the number of narrow NOPs available for aligning
(a subset of wide_nops)
widens = the number of narrow instructions that should be widened
- Desired wide narrow
- Diff nop nop widens
- 1 0 0 1
- 2 0 1 0
- 3a 1 0 0
- b 0 1 1 (case 3a makes this case unnecessary)
- 4a 1 0 1
- b 0 2 0
- c 0 1 2 (case 4a makes this case unnecessary)
- 5a 1 0 2
- b 1 1 0
- c 0 2 1 (case 5b makes this case unnecessary)
- 6a 2 0 0
- b 1 0 3
- c 0 1 4 (case 6b makes this case unnecessary)
- d 1 1 1 (case 6a makes this case unnecessary)
- e 0 2 2 (case 6a makes this case unnecessary)
- f 0 3 0 (case 6a makes this case unnecessary)
- 7a 1 0 4
- b 2 0 1
- c 1 1 2 (case 7b makes this case unnecessary)
- d 0 1 5 (case 7a makes this case unnecessary)
- e 0 2 3 (case 7b makes this case unnecessary)
- f 0 3 1 (case 7b makes this case unnecessary)
- g 1 2 1 (case 7b makes this case unnecessary)
*/
static long
int num_widens,
int desired_diff)
{
+ int nops_needed;
+ int nop_bytes;
+ int extra_bytes;
int bytes_short = desired_diff - num_widens;
gas_assert (desired_diff >= 0
/* From here we will need at least one NOP to get an alignment.
However, we may not be able to align at all, in which case,
don't widen. */
- if (this_frag->fr_subtype == RELAX_FILL_NOP)
+ nops_needed = desired_diff / 3;
+
+ /* If there aren't enough nops, don't widen. */
+ if (nops_needed > wide_nops)
+ return 0;
+
+ /* First try it with all wide nops. */
+ nop_bytes = nops_needed * 3;
+ extra_bytes = desired_diff - nop_bytes;
+
+ if (nop_bytes + num_widens >= desired_diff)
{
- switch (desired_diff)
- {
- case 1:
- return 0;
- case 2:
- if (!this_frag->tc_frag_data.is_no_density && narrow_nops == 1)
- return 2; /* case 2 */
- return 0;
- case 3:
- if (wide_nops > 1)
- return 0;
- else
- return 3; /* case 3a */
- case 4:
- if (num_widens >= 1 && wide_nops == 1)
- return 3; /* case 4a */
- if (!this_frag->tc_frag_data.is_no_density && narrow_nops == 2)
- return 2; /* case 4b */
- return 0;
- case 5:
- if (num_widens >= 2 && wide_nops == 1)
- return 3; /* case 5a */
- /* We will need two nops. Are there enough nops
- between here and the align target? */
- if (wide_nops < 2 || narrow_nops == 0)
- return 0;
- /* Are there other nops closer that can serve instead? */
- if (wide_nops > 2 && narrow_nops > 1)
- return 0;
- /* Take the density one first, because there might not be
- another density one available. */
- if (!this_frag->tc_frag_data.is_no_density)
- return 2; /* case 5b narrow */
- else
- return 3; /* case 5b wide */
- return 0;
- case 6:
- if (wide_nops == 2)
- return 3; /* case 6a */
- else if (num_widens >= 3 && wide_nops == 1)
- return 3; /* case 6b */
- return 0;
- case 7:
- if (wide_nops == 1 && num_widens >= 4)
- return 3; /* case 7a */
- else if (wide_nops == 2 && num_widens >= 1)
- return 3; /* case 7b */
- return 0;
- default:
- gas_assert (0);
- }
+ if (this_frag->fr_subtype == RELAX_FILL_NOP)
+ return 3;
+ else if (num_widens == extra_bytes)
+ return 1;
+ return 0;
}
- else
+
+ /* Add a narrow nop. */
+ nops_needed++;
+ nop_bytes += 2;
+ extra_bytes -= 2;
+ if (narrow_nops == 0 || nops_needed > wide_nops)
+ return 0;
+
+ if (nop_bytes + num_widens >= desired_diff && extra_bytes >= 0)
{
- /* We will need a NOP no matter what, but should we widen
- this instruction to help?
+ if (this_frag->fr_subtype == RELAX_FILL_NOP)
+ return !this_frag->tc_frag_data.is_no_density ? 2 : 3;
+ else if (num_widens == extra_bytes)
+ return 1;
+ return 0;
+ }
- This is a RELAX_NARROW frag. */
- switch (desired_diff)
- {
- case 1:
- gas_assert (0);
- return 0;
- case 2:
- case 3:
- return 0;
- case 4:
- if (wide_nops >= 1 && num_widens == 1)
- return 1; /* case 4a */
- return 0;
- case 5:
- if (wide_nops >= 1 && num_widens == 2)
- return 1; /* case 5a */
- return 0;
- case 6:
- if (wide_nops >= 2)
- return 0; /* case 6a */
- else if (wide_nops >= 1 && num_widens == 3)
- return 1; /* case 6b */
- return 0;
- case 7:
- if (wide_nops >= 1 && num_widens == 4)
- return 1; /* case 7a */
- else if (wide_nops >= 2 && num_widens == 1)
- return 1; /* case 7b */
- return 0;
- default:
- gas_assert (0);
- return 0;
- }
+ /* Replace a wide nop with a narrow nop--we can get here if
+ extra_bytes was negative in the previous conditional. */
+ if (narrow_nops == 1)
+ return 0;
+ nop_bytes--;
+ extra_bytes++;
+ if (nop_bytes + num_widens >= desired_diff)
+ {
+ if (this_frag->fr_subtype == RELAX_FILL_NOP)
+ return !this_frag->tc_frag_data.is_no_density ? 2 : 3;
+ else if (num_widens == extra_bytes)
+ return 1;
+ return 0;
}
- gas_assert (0);
+
+ /* If we can't satisfy any of the above cases, then we can't align
+ using padding or fill nops. */
return 0;
}
projects / deliverable / binutils-gdb.git / commitdiff
