noreorder. */
static int prev_prev_insn_unreordered;
+/* If this is set, it points to a frag holding nop instructions which
+ were inserted before the start of a noreorder section. If those
+ nops turn out to be unnecessary, the size of the frag can be
+ decreased. */
+static fragS *prev_nop_frag;
+
+/* The number of nop instructions we created in prev_nop_frag. */
+static int prev_nop_frag_holds;
+
+/* The number of nop instructions that we know we need in
+ prev_nop_frag. */
+static int prev_nop_frag_required;
+
+/* The number of instructions we've seen since prev_nop_frag. */
+static int prev_nop_frag_since;
+
/* For ECOFF and ELF, relocations against symbols are done in two
parts, with a HI relocation and a LO relocation. Each relocation
has only 16 bits of space to store an addend. This means that in
expressionS * p,
bfd_reloc_code_real_type r,
boolean));
-static void mips_no_prev_insn PARAMS ((void));
+static void mips_no_prev_insn PARAMS ((int));
static void mips_emit_delays PARAMS ((boolean));
#ifdef USE_STDARG
static void macro_build PARAMS ((char *place, int *counter, expressionS * ep,
symbol_table_insert (symbol_new ("$pc", reg_section, -1,
&zero_address_frag));
- mips_no_prev_insn ();
+ mips_no_prev_insn (false);
mips_gprmask = 0;
mips_cprmask[0] = 0;
prev_pinfo = prev_insn.insn_mo->pinfo;
pinfo = ip->insn_mo->pinfo;
- if (place == NULL && ! mips_noreorder)
+ if (place == NULL && (! mips_noreorder || prev_nop_frag != NULL))
{
+ int prev_prev_nop;
+
/* If the previous insn required any delay slots, see if we need
to insert a NOP or two. There are eight kinds of possible
hazards, of which an instruction can have at most one type.
nops += 2;
}
+ /* If the previous instruction was in a noreorder section, then
+ we don't want to insert the nop after all. */
+ if (prev_insn_unreordered)
+ nops = 0;
+
/* There are two cases which require two intervening
instructions: 1) setting the condition codes using a move to
coprocessor instruction which requires a general coprocessor
which have interlocks). If we are not already emitting a NOP
instruction, we must check for these cases compared to the
instruction previous to the previous instruction. */
- if (nops == 0
- && ((! mips16
- && mips_isa < 4
- && (prev_prev_insn.insn_mo->pinfo & INSN_COPROC_MOVE_DELAY)
- && (prev_prev_insn.insn_mo->pinfo & INSN_WRITE_COND_CODE)
- && (pinfo & INSN_READ_COND_CODE)
- && ! cop_interlocks)
- || ((prev_prev_insn.insn_mo->pinfo & INSN_READ_LO)
- && (pinfo & INSN_WRITE_LO)
- && ! interlocks)
- || ((prev_prev_insn.insn_mo->pinfo & INSN_READ_HI)
- && (pinfo & INSN_WRITE_HI)
- && ! interlocks)))
+ if ((! mips16
+ && mips_isa < 4
+ && (prev_prev_insn.insn_mo->pinfo & INSN_COPROC_MOVE_DELAY)
+ && (prev_prev_insn.insn_mo->pinfo & INSN_WRITE_COND_CODE)
+ && (pinfo & INSN_READ_COND_CODE)
+ && ! cop_interlocks)
+ || ((prev_prev_insn.insn_mo->pinfo & INSN_READ_LO)
+ && (pinfo & INSN_WRITE_LO)
+ && ! interlocks)
+ || ((prev_prev_insn.insn_mo->pinfo & INSN_READ_HI)
+ && (pinfo & INSN_WRITE_HI)
+ && ! interlocks))
+ prev_prev_nop = 1;
+ else
+ prev_prev_nop = 0;
+
+ if (prev_prev_insn_unreordered)
+ prev_prev_nop = 0;
+
+ if (prev_prev_nop && nops == 0)
++nops;
/* If we are being given a nop instruction, don't bother with
one of the nops we would otherwise output. This will only
happen when a nop instruction is used with mips_optimize set
to 0. */
- if (nops > 0 && ip->insn_opcode == (mips16 ? 0x6500 : 0))
+ if (nops > 0
+ && ! mips_noreorder
+ && ip->insn_opcode == (mips16 ? 0x6500 : 0))
--nops;
/* Now emit the right number of NOP instructions. */
- if (nops > 0)
+ if (nops > 0 && ! mips_noreorder)
{
fragS *old_frag;
unsigned long old_frag_offset;
ecoff_fix_loc (old_frag, old_frag_offset);
#endif
}
+ else if (prev_nop_frag != NULL)
+ {
+ /* We have a frag holding nops we may be able to remove. If
+ we don't need any nops, we can decrease the size of
+ prev_nop_frag by the size of one instruction. If we do
+ need some nops, we count them in prev_nops_required. */
+ if (prev_nop_frag_since == 0)
+ {
+ if (nops == 0)
+ {
+ prev_nop_frag->fr_fix -= mips16 ? 2 : 4;
+ --prev_nop_frag_holds;
+ }
+ else
+ prev_nop_frag_required += nops;
+ }
+ else
+ {
+ if (prev_prev_nop == 0)
+ {
+ prev_nop_frag->fr_fix -= mips16 ? 2 : 4;
+ --prev_nop_frag_holds;
+ }
+ else
+ ++prev_nop_frag_required;
+ }
+
+ if (prev_nop_frag_holds <= prev_nop_frag_required)
+ prev_nop_frag = NULL;
+
+ ++prev_nop_frag_since;
+
+ /* Sanity check: by the time we reach the second instruction
+ after prev_nop_frag, we should have used up all the nops
+ one way or another. */
+ assert (prev_nop_frag_since <= 1 || prev_nop_frag == NULL);
+ }
}
-
+
if (reloc_type > BFD_RELOC_UNUSED)
{
/* We need to set up a variant frag. */
/* We need to record a bit of information even when we are not
reordering, in order to determine the base address for mips16
PC relative relocs. */
+ prev_prev_insn = prev_insn;
prev_insn = *ip;
prev_insn_reloc_type = reloc_type;
+ prev_prev_insn_unreordered = prev_insn_unreordered;
+ prev_insn_unreordered = 1;
}
/* We just output an insn, so the next one doesn't have a label. */
}
/* This function forgets that there was any previous instruction or
- label. */
+ label. If PRESERVE is non-zero, it remembers enough information to
+ know whether nops are needed before a noreorder section. */
static void
-mips_no_prev_insn ()
+mips_no_prev_insn (preserve)
+ int preserve;
{
- prev_insn.insn_mo = &dummy_opcode;
- prev_prev_insn.insn_mo = &dummy_opcode;
+ if (! preserve)
+ {
+ prev_insn.insn_mo = &dummy_opcode;
+ prev_prev_insn.insn_mo = &dummy_opcode;
+ prev_nop_frag = NULL;
+ prev_nop_frag_holds = 0;
+ prev_nop_frag_required = 0;
+ prev_nop_frag_since = 0;
+ }
prev_insn_valid = 0;
prev_insn_is_delay_slot = 0;
prev_insn_unreordered = 0;
{
if (! mips_noreorder)
{
- int nop;
+ int nops;
- nop = 0;
+ nops = 0;
if ((! mips16
&& mips_isa < 4
&& (! cop_interlocks
& (INSN_LOAD_MEMORY_DELAY
| INSN_COPROC_MEMORY_DELAY))))
{
- nop = 1;
+ ++nops;
if ((! mips16
&& mips_isa < 4
&& (! cop_interlocks
|| (! interlocks
&& ((prev_insn.insn_mo->pinfo & INSN_READ_HI)
|| (prev_insn.insn_mo->pinfo & INSN_READ_LO))))
- emit_nop ();
+ ++nops;
+
+ if (prev_insn_unreordered)
+ nops = 0;
}
else if ((! mips16
&& mips_isa < 4
|| (! interlocks
&& ((prev_prev_insn.insn_mo->pinfo & INSN_READ_HI)
|| (prev_prev_insn.insn_mo->pinfo & INSN_READ_LO))))
- nop = 1;
- if (nop)
+ {
+ if (! prev_prev_insn_unreordered)
+ ++nops;
+ }
+
+ if (nops > 0)
{
struct insn_label_list *l;
- emit_nop ();
+ if (insns)
+ {
+ /* Record the frag which holds the nop instructions, so
+ that we can remove them if we don't need them. */
+ frag_grow (mips16 ? nops * 2 : nops * 4);
+ prev_nop_frag = frag_now;
+ prev_nop_frag_holds = nops;
+ prev_nop_frag_required = 0;
+ prev_nop_frag_since = 0;
+ }
+
+ for (; nops > 0; --nops)
+ emit_nop ();
+
+ if (insns)
+ {
+ /* Move on to a new frag, so that it is safe to simply
+ decrease the size of prev_nop_frag. */
+ frag_wane (frag_now);
+ frag_new (0);
+ }
+
for (l = insn_labels; l != NULL; l = l->next)
{
assert (S_GET_SEGMENT (l->label) == now_seg);
}
}
- mips_no_prev_insn ();
+ mips_no_prev_insn (insns);
}
/* Build an instruction created by a macro expansion. This is passed
case OPTION_MIPS16:
mips16 = 1;
- mips_no_prev_insn ();
+ mips_no_prev_insn (false);
break;
case OPTION_NO_MIPS16:
mips16 = 0;
- mips_no_prev_insn ();
+ mips_no_prev_insn (false);
break;
case OPTION_MEMBEDDED_PIC:
if (strcmp (name, "reorder") == 0)
{
- if (mips_noreorder)
+ if (mips_noreorder && prev_nop_frag != NULL)
{
- prev_insn_unreordered = 1;
- prev_prev_insn_unreordered = 1;
+ /* If we still have pending nops, we can discard them. The
+ usual nop handling will insert any that are still
+ needed. */
+ prev_nop_frag->fr_fix -= prev_nop_frag_holds * (mips16 ? 2 : 4);
+ prev_nop_frag = NULL;
}
mips_noreorder = 0;
}
projects / deliverable / binutils-gdb.git / commitdiff
