static void finish_vinsn (vliw_insn *);
static bfd_boolean emit_single_op (TInsn *);
static int total_frag_text_expansion (fragS *);
+static bfd_boolean use_trampolines = TRUE;
+static void xtensa_check_frag_count (void);
+static void xtensa_create_trampoline_frag (bfd_boolean);
+static void xtensa_maybe_create_trampoline_frag (void);
+struct trampoline_frag;
+static int init_trampoline_frag (struct trampoline_frag *);
/* Alignment Functions. */
static void tinsn_immed_from_frag (TInsn *, fragS *, int);
static int get_num_stack_text_bytes (IStack *);
static int get_num_stack_literal_bytes (IStack *);
+static bfd_boolean tinsn_to_slotbuf (xtensa_format, int, TInsn *, xtensa_insnbuf);
/* vliw_insn functions. */
option_prefer_l32r,
option_prefer_const16,
- option_target_hardware
+ option_target_hardware,
+
+ option_trampolines,
+ option_no_trampolines,
};
const char *md_shortopts = "";
{ "target-hardware", required_argument, NULL, option_target_hardware },
+ { "trampolines", no_argument, NULL, option_trampolines },
+ { "no-trampolines", no_argument, NULL, option_no_trampolines },
+
{ NULL, no_argument, NULL, 0 }
};
directive_state[directive_transform] = FALSE;
return 1;
+ case option_trampolines:
+ use_trampolines = TRUE;
+ return 1;
+
+ case option_no_trampolines:
+ use_trampolines = FALSE;
+ return 1;
+
default:
return 0;
}
flix bundles\n\
--no-allow-flix neither allow hand-written nor generate\n\
flix bundles\n\
- --rename-section old=new Rename section 'old' to 'new'\n", stream);
+ --rename-section old=new Rename section 'old' to 'new'\n\
+ --[no-]trampolines [Do not] generate trampolines (jumps to jumps)\n\
+ when jumps do not reach their targets\n", stream);
}
\f
/* We've just emitted a new instruction so clear the list of labels. */
xtensa_clear_insn_labels ();
+
+ xtensa_check_frag_count ();
}
xg_assemble_vliw_tokens (vinsn);
xg_clear_vinsn (vinsn);
+
+ xtensa_check_frag_count ();
}
RELAX_UNREACHABLE,
frag_now->fr_symbol, frag_now->fr_offset, NULL);
xtensa_set_frag_assembly_state (frag_now);
+ xtensa_maybe_create_trampoline_frag ();
}
else if (is_branch && do_align_targets ())
{
xtensa_sanity_check ();
xtensa_add_config_info ();
+
+ xtensa_check_frag_count ();
+}
+
+
+struct trampoline_frag
+{
+ struct trampoline_frag *next;
+ bfd_boolean needs_jump_around;
+ fragS *fragP;
+ fixS *fixP;
+};
+
+struct trampoline_seg
+{
+ struct trampoline_seg *next;
+ asection *seg;
+ struct trampoline_frag trampoline_list;
+};
+
+static struct trampoline_seg trampoline_seg_list;
+#define J_RANGE (128 * 1024)
+
+static int unreachable_count = 0;
+
+
+static void
+xtensa_maybe_create_trampoline_frag (void)
+{
+ if (!use_trampolines)
+ return;
+
+ /* We create an area for possible trampolines every 10 unreachable frags.
+ These are preferred over the ones not preceded by an unreachable frag,
+ because we don't have to jump around them. This function is called after
+ each RELAX_UNREACHABLE frag is created. */
+
+ if (++unreachable_count > 10)
+ {
+ xtensa_create_trampoline_frag (FALSE);
+ clear_frag_count ();
+ unreachable_count = 0;
+ }
+}
+
+static void
+xtensa_check_frag_count (void)
+{
+ if (!use_trampolines || frag_now->tc_frag_data.is_no_transform)
+ return;
+
+ /* We create an area for possible trampolines every 8000 frags or so. This
+ is an estimate based on the max range of a "j" insn (+/-128K) divided
+ by a typical frag byte count (16), minus a few for safety. This function
+ is called after each source line is processed. */
+
+ if (get_frag_count () > 8000)
+ {
+ xtensa_create_trampoline_frag (TRUE);
+ clear_frag_count ();
+ unreachable_count = 0;
+ }
+}
+
+static xtensa_insnbuf trampoline_buf = NULL;
+static xtensa_insnbuf trampoline_slotbuf = NULL;
+
+#define TRAMPOLINE_FRAG_SIZE 3000
+
+static void
+xtensa_create_trampoline_frag (bfd_boolean needs_jump_around)
+{
+ /* Emit a frag where we can place intermediate jump instructions,
+ in case we need to jump farther than 128K bytes.
+ Each jump instruction takes three bytes.
+ We allocate enough for 1000 trampolines in each frag.
+ If that's not enough, oh well. */
+
+ struct trampoline_seg *ts = trampoline_seg_list.next;
+ struct trampoline_frag *tf;
+ char *varP;
+ fragS *fragP;
+ int size = TRAMPOLINE_FRAG_SIZE;
+
+ for ( ; ts; ts = ts->next)
+ {
+ if (ts->seg == now_seg)
+ break;
+ }
+
+ if (ts == NULL)
+ {
+ ts = (struct trampoline_seg *)xcalloc(sizeof (struct trampoline_seg), 1);
+ ts->next = trampoline_seg_list.next;
+ trampoline_seg_list.next = ts;
+ ts->seg = now_seg;
+ }
+
+ frag_wane (frag_now);
+ frag_new (0);
+ xtensa_set_frag_assembly_state (frag_now);
+ varP = frag_var (rs_machine_dependent, size, size, RELAX_TRAMPOLINE, NULL, 0, NULL);
+ fragP = (fragS *)(varP - SIZEOF_STRUCT_FRAG);
+ if (trampoline_buf == NULL)
+ {
+ trampoline_buf = xtensa_insnbuf_alloc (xtensa_default_isa);
+ trampoline_slotbuf = xtensa_insnbuf_alloc (xtensa_default_isa);
+ }
+ tf = (struct trampoline_frag *)xmalloc(sizeof (struct trampoline_frag));
+ tf->next = ts->trampoline_list.next;
+ ts->trampoline_list.next = tf;
+ tf->needs_jump_around = needs_jump_around;
+ tf->fragP = fragP;
+ tf->fixP = NULL;
+}
+
+
+static struct trampoline_seg *
+find_trampoline_seg (asection *seg)
+{
+ struct trampoline_seg *ts = trampoline_seg_list.next;
+
+ for ( ; ts; ts = ts->next)
+ {
+ if (ts->seg == seg)
+ return ts;
+ }
+
+ return NULL;
}
+void dump_trampolines (void);
+
+void
+dump_trampolines (void)
+{
+ struct trampoline_seg *ts = trampoline_seg_list.next;
+
+ for ( ; ts; ts = ts->next)
+ {
+ asection *seg = ts->seg;
+
+ if (seg == NULL)
+ continue;
+ fprintf(stderr, "SECTION %s\n", seg->name);
+ struct trampoline_frag *tf = ts->trampoline_list.next;
+ for ( ; tf; tf = tf->next)
+ {
+ if (tf->fragP == NULL)
+ continue;
+ fprintf(stderr, " 0x%08x: fix=%d, jump_around=%s\n",
+ (int)tf->fragP->fr_address, (int)tf->fragP->fr_fix,
+ tf->needs_jump_around ? "T" : "F");
+ }
+ }
+}
+
static void
xtensa_cleanup_align_frags (void)
{
new_stretch += relax_frag_for_align (fragP, stretch);
break;
+ case RELAX_TRAMPOLINE:
+ if (fragP->tc_frag_data.relax_seen)
+ {
+ segment_info_type *seginfo = seg_info (now_seg);
+ fragS *fP; /* The out-of-range jump. */
+ fixS *fixP;
+
+ /* Scan for jumps that will not reach. */
+ for (fixP = seginfo->fix_root; fixP ; fixP = fixP->fx_next)
+ {
+ symbolS *s = fixP->fx_addsy;
+ xtensa_opcode opcode;
+ int target;
+ int addr;
+ int delta;
+
+ if (fixP->fx_r_type < BFD_RELOC_XTENSA_SLOT0_OP ||
+ fixP->fx_r_type > BFD_RELOC_XTENSA_SLOT14_OP)
+ continue;
+ xtensa_insnbuf_from_chars (isa, trampoline_buf,
+ (unsigned char *) fixP->fx_frag->fr_literal + fixP->fx_where,
+ 0);
+ fmt = xtensa_format_decode (isa, trampoline_buf);
+ gas_assert (fmt != XTENSA_UNDEFINED);
+ slot = fixP->tc_fix_data.slot;
+ xtensa_format_get_slot (isa, fmt, slot, trampoline_buf, trampoline_slotbuf);
+ opcode = xtensa_opcode_decode (isa, fmt, slot, trampoline_slotbuf);
+ if (opcode != xtensa_j_opcode)
+ continue;
+ target = S_GET_VALUE (s);
+ addr = fixP->fx_frag->fr_address;
+ delta = target - addr + stretch;
+ if (delta > J_RANGE || delta < -1 * J_RANGE)
+ { /* Found an out-of-range jump; scan the list of trampolines for the best match. */
+ struct trampoline_seg *ts = find_trampoline_seg (now_seg);
+ struct trampoline_frag *tf = ts->trampoline_list.next;
+ struct trampoline_frag *prev = &ts->trampoline_list;
+ int lower = (target < addr) ? target : addr;
+ int upper = (target > addr) ? target : addr;
+ int midpoint = lower + (upper - lower) / 2;
+
+ if ((upper - lower) > 2 * J_RANGE)
+ {
+ /* One trampoline won't suffice; we need multiple jumps.
+ Jump to the trampoline that's farthest, but still in
+ range relative to the original "j" instruction. */
+ for ( ; tf; prev = tf, tf = tf->next )
+ {
+ int this_addr = tf->fragP->fr_address + tf->fragP->fr_fix;
+ int next_addr = (tf->next) ? tf->next->fragP->fr_address + tf->next->fragP->fr_fix : 0 ;
+
+ if (addr == lower)
+ {
+ /* Forward jump. */
+ if (this_addr - addr < J_RANGE)
+ break;
+ }
+ else
+ {
+ /* Backward jump. */
+ if (next_addr == 0 || addr - next_addr > J_RANGE)
+ break;
+ }
+ }
+ }
+ else
+ {
+ struct trampoline_frag *best_tf = NULL;
+ int best_delta = 0;
+
+ for ( ; tf; prev = tf, tf = tf->next )
+ {
+ int this_addr = tf->fragP->fr_address + tf->fragP->fr_fix;
+ int this_delta = abs (this_addr - midpoint);
+
+ if (!best_tf || this_delta < best_delta)
+ {
+ best_tf = tf;
+ best_delta = this_delta;
+ }
+ }
+ tf = best_tf;
+ }
+ if (tf->fragP == fragP)
+ {
+ int trampaddr = fragP->fr_address + fragP->fr_fix;
+
+ if (abs (addr - trampaddr) < J_RANGE)
+ { /* The trampoline is in range of original; fix it! */
+ fixS *newfixP;
+ int offset;
+ TInsn insn;
+ symbolS *lsym;
+
+ new_stretch += init_trampoline_frag (tf);
+ offset = fragP->fr_fix; /* Where to assemble the j insn. */
+ lsym = fragP->fr_symbol;
+ fP = fixP->fx_frag;
+ /* Assemble a jump to the target label here. */
+ tinsn_init (&insn);
+ insn.insn_type = ITYPE_INSN;
+ insn.opcode = xtensa_j_opcode;
+ insn.ntok = 1;
+ set_expr_symbol_offset (&insn.tok[0], lsym, offset);
+ fmt = xg_get_single_format (xtensa_j_opcode);
+ tinsn_to_slotbuf (fmt, 0, &insn, trampoline_slotbuf);
+ xtensa_format_set_slot (isa, fmt, 0, trampoline_buf, trampoline_slotbuf);
+ xtensa_insnbuf_to_chars (isa, trampoline_buf, (unsigned char *)fragP->fr_literal + offset, 3);
+ fragP->fr_fix += 3;
+ fragP->fr_var -= 3;
+ /* Add a fix-up for the original j insn. */
+ newfixP = fix_new (fP, fixP->fx_where, fixP->fx_size, lsym, fragP->fr_fix - 3, TRUE, fixP->fx_r_type);
+ newfixP->fx_no_overflow = 1;
+ newfixP->tc_fix_data.X_add_symbol = lsym;
+ newfixP->tc_fix_data.X_add_number = offset;
+ newfixP->tc_fix_data.slot = slot;
+ /* Move the fix-up from the original j insn to this one. */
+ fixP->fx_frag = fragP;
+ fixP->fx_where = fragP->fr_fix - 3;
+ fixP->tc_fix_data.slot = 0;
+ /* Adjust the jump around this trampoline (if present). */
+ if (tf->fixP != NULL)
+ {
+ tf->fixP->fx_offset += 3;
+ }
+ new_stretch += 3;
+ fragP->tc_frag_data.relax_seen = FALSE; /* Need another pass. */
+ /* Do we have room for more? */
+ if (fragP->fr_var < 3)
+ { /* No, convert to fill. */
+ frag_wane (fragP);
+ fragP->fr_subtype = 0;
+ /* Remove from the trampoline_list. */
+ prev->next = tf->next;
+ break;
+ }
+ }
+ }
+ }
+ }
+ }
+ break;
+
default:
as_bad (_("bad relaxation state"));
}
}
+static struct trampoline_frag *
+search_trampolines (TInsn *tinsn, fragS *fragP, bfd_boolean unreachable_only)
+{
+ struct trampoline_seg *ts = find_trampoline_seg (now_seg);
+ struct trampoline_frag *tf = (ts) ? ts->trampoline_list.next : NULL;
+ struct trampoline_frag *best_tf = NULL;
+ int best_delta = 0;
+ int best_addr = 0;
+ symbolS *sym = tinsn->tok[0].X_add_symbol;
+ offsetT target = S_GET_VALUE (sym) + tinsn->tok[0].X_add_number;
+ offsetT addr = fragP->fr_address;
+ offsetT lower = (addr < target) ? addr : target;
+ offsetT upper = (addr > target) ? addr : target;
+ int delta = upper - lower;
+ offsetT midpoint = lower + delta / 2;
+ int this_delta = -1;
+ int this_addr = -1;
+
+ if (delta > 2 * J_RANGE)
+ {
+ /* One trampoline won't do; we need multiple.
+ Choose the farthest trampoline that's still in range of the original
+ and let a later pass finish the job. */
+ for ( ; tf; tf = tf->next)
+ {
+ int next_addr = (tf->next) ? tf->next->fragP->fr_address + tf->next->fragP->fr_fix : 0;
+
+ this_addr = tf->fragP->fr_address + tf->fragP->fr_fix;
+ if (lower == addr)
+ {
+ /* Forward jump. */
+ if (this_addr - addr < J_RANGE)
+ break;
+ }
+ else
+ {
+ /* Backward jump. */
+ if (next_addr == 0 || addr - next_addr > J_RANGE)
+ break;
+ }
+ if (abs (addr - this_addr) < J_RANGE)
+ return tf;
+
+ return NULL;
+ }
+ }
+ for ( ; tf; tf = tf->next)
+ {
+ this_addr = tf->fragP->fr_address + tf->fragP->fr_fix;
+ this_delta = abs (this_addr - midpoint);
+ if (unreachable_only && tf->needs_jump_around)
+ continue;
+ if (!best_tf || this_delta < best_delta)
+ {
+ best_tf = tf;
+ best_delta = this_delta;
+ best_addr = this_addr;
+ }
+ }
+
+ if (best_tf &&
+ best_delta < J_RANGE &&
+ abs(best_addr - lower) < J_RANGE &&
+ abs(best_addr - upper) < J_RANGE)
+ return best_tf;
+
+ return NULL; /* No suitable trampoline found. */
+}
+
+
+static struct trampoline_frag *
+get_best_trampoline (TInsn *tinsn, fragS *fragP)
+{
+ struct trampoline_frag *tf = NULL;
+
+ tf = search_trampolines (tinsn, fragP, TRUE); /* Try unreachable first. */
+
+ if (tf == NULL)
+ tf = search_trampolines (tinsn, fragP, FALSE); /* Try ones needing a jump-around, too. */
+
+ return tf;
+}
+
+
+static void
+check_and_update_trampolines (void)
+{
+ struct trampoline_seg *ts = find_trampoline_seg (now_seg);
+ struct trampoline_frag *tf = ts->trampoline_list.next;
+ struct trampoline_frag *prev = &ts->trampoline_list;
+
+ for ( ; tf; prev = tf, tf = tf->next)
+ {
+ if (tf->fragP->fr_var < 3)
+ {
+ frag_wane (tf->fragP);
+ prev->next = tf->next;
+ tf->fragP = NULL;
+ }
+ }
+}
+
+
+static int
+init_trampoline_frag (struct trampoline_frag *trampP)
+{
+ fragS *fp = trampP->fragP;
+ int growth = 0;
+
+ if (fp->fr_fix == 0)
+ {
+ symbolS *lsym;
+ char label[10 + 2 * sizeof(fp)];
+ sprintf (label, ".L0_TR_%p", fp);
+
+ lsym = (symbolS *)local_symbol_make (label, now_seg, 0, fp);
+ fp->fr_symbol = lsym;
+ if (trampP->needs_jump_around)
+ {
+ /* Add a jump around this block of jumps, in case
+ control flows into this block. */
+ fixS *fixP;
+ TInsn insn;
+ xtensa_format fmt;
+ xtensa_isa isa = xtensa_default_isa;
+
+ fp->tc_frag_data.is_insn = 1;
+ /* Assemble a jump insn. */
+ tinsn_init (&insn);
+ insn.insn_type = ITYPE_INSN;
+ insn.opcode = xtensa_j_opcode;
+ insn.ntok = 1;
+ set_expr_symbol_offset (&insn.tok[0], lsym, 3);
+ fmt = xg_get_single_format (xtensa_j_opcode);
+ tinsn_to_slotbuf (fmt, 0, &insn, trampoline_slotbuf);
+ xtensa_format_set_slot (isa, fmt, 0, trampoline_buf, trampoline_slotbuf);
+ xtensa_insnbuf_to_chars (isa, trampoline_buf, (unsigned char *)fp->fr_literal, 3);
+ fp->fr_fix += 3;
+ fp->fr_var -= 3;
+ growth = 3;
+ fixP = fix_new (fp, 0, 3, lsym, 3, TRUE, BFD_RELOC_XTENSA_SLOT0_OP);
+ trampP->fixP = fixP;
+ }
+ }
+ return growth;
+}
+
+
+static int
+add_jump_to_trampoline (struct trampoline_frag *trampP, fragS *origfrag)
+{
+ fragS *tramp = trampP->fragP;
+ fixS *fixP;
+ int offset = tramp->fr_fix; /* Where to assemble the j insn. */
+ TInsn insn;
+ symbolS *lsym;
+ symbolS *tsym;
+ int toffset;
+ xtensa_format fmt;
+ xtensa_isa isa = xtensa_default_isa;
+ int growth = 0;
+
+ lsym = tramp->fr_symbol;
+ /* Assemble a jump to the target label in the trampoline frag. */
+ tsym = origfrag->tc_frag_data.slot_symbols[0];
+ toffset = origfrag-> tc_frag_data.slot_offsets[0];
+ tinsn_init (&insn);
+ insn.insn_type = ITYPE_INSN;
+ insn.opcode = xtensa_j_opcode;
+ insn.ntok = 1;
+ set_expr_symbol_offset (&insn.tok[0], tsym, toffset);
+ fmt = xg_get_single_format (xtensa_j_opcode);
+ tinsn_to_slotbuf (fmt, 0, &insn, trampoline_slotbuf);
+ xtensa_format_set_slot (isa, fmt, 0, trampoline_buf, trampoline_slotbuf);
+ xtensa_insnbuf_to_chars (isa, trampoline_buf, (unsigned char *)tramp->fr_literal + offset, 3);
+ tramp->fr_fix += 3;
+ tramp->fr_var -= 3;
+ growth = 3;
+ /* add a fix-up for the trampoline jump. */
+ fixP = fix_new (tramp, tramp->fr_fix - 3, 3, tsym, toffset, TRUE, BFD_RELOC_XTENSA_SLOT0_OP);
+ /* Modify the jump at the start of this trampoline to point past the newly-added jump. */
+ fixP = trampP->fixP;
+ if (fixP)
+ fixP->fx_offset += 3;
+ /* Modify the original j to point here. */
+ origfrag->tc_frag_data.slot_symbols[0] = lsym;
+ origfrag->tc_frag_data.slot_offsets[0] = tramp->fr_fix - 3;
+ /* If trampoline is full, remove it from the list. */
+ check_and_update_trampolines ();
+
+ return growth;
+}
+
+
static long
relax_frag_immed (segT segP,
fragS *fragP,
if (negatable_branch && istack.ninsn > 1)
update_next_frag_state (fragP);
+ /* If last insn is a jump, and it cannot reach its target, try to find a trampoline. */
+ if (istack.ninsn > 2 &&
+ istack.insn[istack.ninsn - 1].insn_type == ITYPE_LABEL &&
+ istack.insn[istack.ninsn - 2].insn_type == ITYPE_INSN &&
+ istack.insn[istack.ninsn - 2].opcode == xtensa_j_opcode)
+ {
+ TInsn *jinsn = &istack.insn[istack.ninsn - 2];
+
+ if (!xg_symbolic_immeds_fit (jinsn, segP, fragP, fragP->fr_offset, total_text_diff))
+ {
+ struct trampoline_frag *tf = get_best_trampoline (jinsn, fragP);
+
+ if (tf)
+ {
+ this_text_diff += init_trampoline_frag (tf);
+ this_text_diff += add_jump_to_trampoline (tf, fragP);
+ }
+ else
+ {
+ /* If target symbol is undefined, assume it will reach once linked. */
+ expressionS *exp = &istack.insn[istack.ninsn - 2].tok[0];
+
+ if (exp->X_op == O_symbol && S_IS_DEFINED (exp->X_add_symbol))
+ {
+ as_bad_where (fragP->fr_file, fragP->fr_line,
+ _("jump target out of range; no usable trampoline found"));
+ }
+ }
+ }
+ }
+
return this_text_diff;
}
else
as_bad (_("invalid relaxation fragment result"));
break;
+
+ case RELAX_TRAMPOLINE:
+ break;
}
fragp->fr_var = 0;
projects / deliverable / binutils-gdb.git / blobdiff