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caller-save.c
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caller-save.c
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/* Save and restore call-clobbered registers which are live across a call.
Copyright (C) 1989, 1992, 1994, 1995, 1997, 1998, 1999, 2000,
2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
#include "regs.h"
#include "insn-config.h"
#include "flags.h"
#include "hard-reg-set.h"
#include "recog.h"
#include "basic-block.h"
#include "df.h"
#include "reload.h"
#include "function.h"
#include "expr.h"
#include "diagnostic-core.h"
#include "tm_p.h"
#include "addresses.h"
#include "output.h"
#include "ggc.h"
#define MOVE_MAX_WORDS (MOVE_MAX / UNITS_PER_WORD)
#define regno_save_mode \
(this_target_reload->x_regno_save_mode)
#define cached_reg_save_code \
(this_target_reload->x_cached_reg_save_code)
#define cached_reg_restore_code \
(this_target_reload->x_cached_reg_restore_code)
/* For each hard register, a place on the stack where it can be saved,
if needed. */
static rtx
regno_save_mem[FIRST_PSEUDO_REGISTER][MAX_MOVE_MAX / MIN_UNITS_PER_WORD + 1];
/* The number of elements in the subsequent array. */
static int save_slots_num;
/* Allocated slots so far. */
static rtx save_slots[FIRST_PSEUDO_REGISTER];
/* Set of hard regs currently residing in save area (during insn scan). */
static HARD_REG_SET hard_regs_saved;
/* Number of registers currently in hard_regs_saved. */
static int n_regs_saved;
/* Computed by mark_referenced_regs, all regs referenced in a given
insn. */
static HARD_REG_SET referenced_regs;
typedef void refmarker_fn (rtx *loc, enum machine_mode mode, int hardregno,
void *mark_arg);
static int reg_save_code (int, enum machine_mode);
static int reg_restore_code (int, enum machine_mode);
struct saved_hard_reg;
static void initiate_saved_hard_regs (void);
static void new_saved_hard_reg (int, int);
static void finish_saved_hard_regs (void);
static int saved_hard_reg_compare_func (const void *, const void *);
static void mark_set_regs (rtx, const_rtx, void *);
static void mark_referenced_regs (rtx *, refmarker_fn *mark, void *mark_arg);
static refmarker_fn mark_reg_as_referenced;
static refmarker_fn replace_reg_with_saved_mem;
static int insert_save (struct insn_chain *, int, int, HARD_REG_SET *,
enum machine_mode *);
static int insert_restore (struct insn_chain *, int, int, int,
enum machine_mode *);
static struct insn_chain *insert_one_insn (struct insn_chain *, int, int,
rtx);
static void add_stored_regs (rtx, const_rtx, void *);
static GTY(()) rtx savepat;
static GTY(()) rtx restpat;
static GTY(()) rtx test_reg;
static GTY(()) rtx test_mem;
static GTY(()) rtx saveinsn;
static GTY(()) rtx restinsn;
/* Return the INSN_CODE used to save register REG in mode MODE. */
static int
reg_save_code (int reg, enum machine_mode mode)
{
bool ok;
if (cached_reg_save_code[reg][mode])
return cached_reg_save_code[reg][mode];
if (!HARD_REGNO_MODE_OK (reg, mode))
{
/* Depending on how HARD_REGNO_MODE_OK is defined, range propagation
might deduce here that reg >= FIRST_PSEUDO_REGISTER. So the assert
below silences a warning. */
gcc_assert (reg < FIRST_PSEUDO_REGISTER);
cached_reg_save_code[reg][mode] = -1;
cached_reg_restore_code[reg][mode] = -1;
return -1;
}
/* Update the register number and modes of the register
and memory operand. */
SET_REGNO_RAW (test_reg, reg);
PUT_MODE (test_reg, mode);
PUT_MODE (test_mem, mode);
/* Force re-recognition of the modified insns. */
INSN_CODE (saveinsn) = -1;
INSN_CODE (restinsn) = -1;
cached_reg_save_code[reg][mode] = recog_memoized (saveinsn);
cached_reg_restore_code[reg][mode] = recog_memoized (restinsn);
/* Now extract both insns and see if we can meet their
constraints. */
ok = (cached_reg_save_code[reg][mode] != -1
&& cached_reg_restore_code[reg][mode] != -1);
if (ok)
{
extract_insn (saveinsn);
ok = constrain_operands (1);
extract_insn (restinsn);
ok &= constrain_operands (1);
}
if (! ok)
{
cached_reg_save_code[reg][mode] = -1;
cached_reg_restore_code[reg][mode] = -1;
}
gcc_assert (cached_reg_save_code[reg][mode]);
return cached_reg_save_code[reg][mode];
}
/* Return the INSN_CODE used to restore register REG in mode MODE. */
static int
reg_restore_code (int reg, enum machine_mode mode)
{
if (cached_reg_restore_code[reg][mode])
return cached_reg_restore_code[reg][mode];
/* Populate our cache. */
reg_save_code (reg, mode);
return cached_reg_restore_code[reg][mode];
}
/* Initialize for caller-save.
Look at all the hard registers that are used by a call and for which
reginfo.c has not already excluded from being used across a call.
Ensure that we can find a mode to save the register and that there is a
simple insn to save and restore the register. This latter check avoids
problems that would occur if we tried to save the MQ register of some
machines directly into memory. */
void
init_caller_save (void)
{
rtx addr_reg;
int offset;
rtx address;
int i, j;
if (caller_save_initialized_p)
return;
caller_save_initialized_p = true;
CLEAR_HARD_REG_SET (no_caller_save_reg_set);
/* First find all the registers that we need to deal with and all
the modes that they can have. If we can't find a mode to use,
we can't have the register live over calls. */
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
{
if (call_used_regs[i]
&& !TEST_HARD_REG_BIT (call_fixed_reg_set, i))
{
for (j = 1; j <= MOVE_MAX_WORDS; j++)
{
regno_save_mode[i][j] = HARD_REGNO_CALLER_SAVE_MODE (i, j,
VOIDmode);
if (regno_save_mode[i][j] == VOIDmode && j == 1)
{
SET_HARD_REG_BIT (call_fixed_reg_set, i);
}
}
}
else
regno_save_mode[i][1] = VOIDmode;
}
/* The following code tries to approximate the conditions under which
we can easily save and restore a register without scratch registers or
other complexities. It will usually work, except under conditions where
the validity of an insn operand is dependent on the address offset.
No such cases are currently known.
We first find a typical offset from some BASE_REG_CLASS register.
This address is chosen by finding the first register in the class
and by finding the smallest power of two that is a valid offset from
that register in every mode we will use to save registers. */
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
if (TEST_HARD_REG_BIT
(reg_class_contents
[(int) base_reg_class (regno_save_mode[i][1], PLUS, CONST_INT)], i))
break;
gcc_assert (i < FIRST_PSEUDO_REGISTER);
addr_reg = gen_rtx_REG (Pmode, i);
for (offset = 1 << (HOST_BITS_PER_INT / 2); offset; offset >>= 1)
{
address = gen_rtx_PLUS (Pmode, addr_reg, GEN_INT (offset));
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
if (regno_save_mode[i][1] != VOIDmode
&& ! strict_memory_address_p (regno_save_mode[i][1], address))
break;
if (i == FIRST_PSEUDO_REGISTER)
break;
}
/* If we didn't find a valid address, we must use register indirect. */
if (offset == 0)
address = addr_reg;
/* Next we try to form an insn to save and restore the register. We
see if such an insn is recognized and meets its constraints.
To avoid lots of unnecessary RTL allocation, we construct all the RTL
once, then modify the memory and register operands in-place. */
test_reg = gen_rtx_REG (VOIDmode, 0);
test_mem = gen_rtx_MEM (VOIDmode, address);
savepat = gen_rtx_SET (VOIDmode, test_mem, test_reg);
restpat = gen_rtx_SET (VOIDmode, test_reg, test_mem);
saveinsn = gen_rtx_INSN (VOIDmode, 0, 0, 0, 0, savepat, 0, -1, 0);
restinsn = gen_rtx_INSN (VOIDmode, 0, 0, 0, 0, restpat, 0, -1, 0);
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
for (j = 1; j <= MOVE_MAX_WORDS; j++)
if (reg_save_code (i,regno_save_mode[i][j]) == -1)
{
regno_save_mode[i][j] = VOIDmode;
if (j == 1)
{
SET_HARD_REG_BIT (call_fixed_reg_set, i);
if (call_used_regs[i])
SET_HARD_REG_BIT (no_caller_save_reg_set, i);
}
}
}
/* Initialize save areas by showing that we haven't allocated any yet. */
void
init_save_areas (void)
{
int i, j;
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
for (j = 1; j <= MOVE_MAX_WORDS; j++)
regno_save_mem[i][j] = 0;
save_slots_num = 0;
}
/* The structure represents a hard register which should be saved
through the call. It is used when the integrated register
allocator (IRA) is used and sharing save slots is on. */
struct saved_hard_reg
{
/* Order number starting with 0. */
int num;
/* The hard regno. */
int hard_regno;
/* Execution frequency of all calls through which given hard
register should be saved. */
int call_freq;
/* Stack slot reserved to save the hard register through calls. */
rtx slot;
/* True if it is first hard register in the chain of hard registers
sharing the same stack slot. */
int first_p;
/* Order number of the next hard register structure with the same
slot in the chain. -1 represents end of the chain. */
int next;
};
/* Map: hard register number to the corresponding structure. */
static struct saved_hard_reg *hard_reg_map[FIRST_PSEUDO_REGISTER];
/* The number of all structures representing hard registers should be
saved, in order words, the number of used elements in the following
array. */
static int saved_regs_num;
/* Pointers to all the structures. Index is the order number of the
corresponding structure. */
static struct saved_hard_reg *all_saved_regs[FIRST_PSEUDO_REGISTER];
/* First called function for work with saved hard registers. */
static void
initiate_saved_hard_regs (void)
{
int i;
saved_regs_num = 0;
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
hard_reg_map[i] = NULL;
}
/* Allocate and return new saved hard register with given REGNO and
CALL_FREQ. */
static void
new_saved_hard_reg (int regno, int call_freq)
{
struct saved_hard_reg *saved_reg;
saved_reg
= (struct saved_hard_reg *) xmalloc (sizeof (struct saved_hard_reg));
hard_reg_map[regno] = all_saved_regs[saved_regs_num] = saved_reg;
saved_reg->num = saved_regs_num++;
saved_reg->hard_regno = regno;
saved_reg->call_freq = call_freq;
saved_reg->first_p = FALSE;
saved_reg->next = -1;
}
/* Free memory allocated for the saved hard registers. */
static void
finish_saved_hard_regs (void)
{
int i;
for (i = 0; i < saved_regs_num; i++)
free (all_saved_regs[i]);
}
/* The function is used to sort the saved hard register structures
according their frequency. */
static int
saved_hard_reg_compare_func (const void *v1p, const void *v2p)
{
const struct saved_hard_reg *p1 = *(struct saved_hard_reg * const *) v1p;
const struct saved_hard_reg *p2 = *(struct saved_hard_reg * const *) v2p;
if (flag_omit_frame_pointer)
{
if (p1->call_freq - p2->call_freq != 0)
return p1->call_freq - p2->call_freq;
}
else if (p2->call_freq - p1->call_freq != 0)
return p2->call_freq - p1->call_freq;
return p1->num - p2->num;
}
/* Allocate save areas for any hard registers that might need saving.
We take a conservative approach here and look for call-clobbered hard
registers that are assigned to pseudos that cross calls. This may
overestimate slightly (especially if some of these registers are later
used as spill registers), but it should not be significant.
For IRA we use priority coloring to decrease stack slots needed for
saving hard registers through calls. We build conflicts for them
to do coloring.
Future work:
In the fallback case we should iterate backwards across all possible
modes for the save, choosing the largest available one instead of
falling back to the smallest mode immediately. (eg TF -> DF -> SF).
We do not try to use "move multiple" instructions that exist
on some machines (such as the 68k moveml). It could be a win to try
and use them when possible. The hard part is doing it in a way that is
machine independent since they might be saving non-consecutive
registers. (imagine caller-saving d0,d1,a0,a1 on the 68k) */
void
setup_save_areas (void)
{
int i, j, k, freq;
HARD_REG_SET hard_regs_used;
struct saved_hard_reg *saved_reg;
rtx insn;
struct insn_chain *chain, *next;
unsigned int regno;
HARD_REG_SET hard_regs_to_save, used_regs, this_insn_sets;
reg_set_iterator rsi;
CLEAR_HARD_REG_SET (hard_regs_used);
/* Find every CALL_INSN and record which hard regs are live across the
call into HARD_REG_MAP and HARD_REGS_USED. */
initiate_saved_hard_regs ();
/* Create hard reg saved regs. */
for (chain = reload_insn_chain; chain != 0; chain = next)
{
insn = chain->insn;
next = chain->next;
if (!CALL_P (insn)
|| find_reg_note (insn, REG_NORETURN, NULL))
continue;
freq = REG_FREQ_FROM_BB (BLOCK_FOR_INSN (insn));
REG_SET_TO_HARD_REG_SET (hard_regs_to_save,
&chain->live_throughout);
COPY_HARD_REG_SET (used_regs, call_used_reg_set);
/* Record all registers set in this call insn. These don't
need to be saved. N.B. the call insn might set a subreg
of a multi-hard-reg pseudo; then the pseudo is considered
live during the call, but the subreg that is set
isn't. */
CLEAR_HARD_REG_SET (this_insn_sets);
note_stores (PATTERN (insn), mark_set_regs, &this_insn_sets);
/* Sibcalls are considered to set the return value. */
if (SIBLING_CALL_P (insn) && crtl->return_rtx)
mark_set_regs (crtl->return_rtx, NULL_RTX, &this_insn_sets);
AND_COMPL_HARD_REG_SET (used_regs, call_fixed_reg_set);
AND_COMPL_HARD_REG_SET (used_regs, this_insn_sets);
AND_HARD_REG_SET (hard_regs_to_save, used_regs);
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
if (TEST_HARD_REG_BIT (hard_regs_to_save, regno))
{
if (hard_reg_map[regno] != NULL)
hard_reg_map[regno]->call_freq += freq;
else
new_saved_hard_reg (regno, freq);
SET_HARD_REG_BIT (hard_regs_used, regno);
}
/* Look through all live pseudos, mark their hard registers. */
EXECUTE_IF_SET_IN_REG_SET
(&chain->live_throughout, FIRST_PSEUDO_REGISTER, regno, rsi)
{
int r = reg_renumber[regno];
int bound;
if (r < 0)
continue;
bound = r + hard_regno_nregs[r][PSEUDO_REGNO_MODE (regno)];
for (; r < bound; r++)
if (TEST_HARD_REG_BIT (used_regs, r))
{
if (hard_reg_map[r] != NULL)
hard_reg_map[r]->call_freq += freq;
else
new_saved_hard_reg (r, freq);
SET_HARD_REG_BIT (hard_regs_to_save, r);
SET_HARD_REG_BIT (hard_regs_used, r);
}
}
}
/* If requested, figure out which hard regs can share save slots. */
if (optimize && flag_ira_share_save_slots)
{
rtx slot;
char *saved_reg_conflicts;
int next_k;
struct saved_hard_reg *saved_reg2, *saved_reg3;
int call_saved_regs_num;
struct saved_hard_reg *call_saved_regs[FIRST_PSEUDO_REGISTER];
int best_slot_num;
int prev_save_slots_num;
rtx prev_save_slots[FIRST_PSEUDO_REGISTER];
/* Find saved hard register conflicts. */
saved_reg_conflicts = (char *) xmalloc (saved_regs_num * saved_regs_num);
memset (saved_reg_conflicts, 0, saved_regs_num * saved_regs_num);
for (chain = reload_insn_chain; chain != 0; chain = next)
{
call_saved_regs_num = 0;
insn = chain->insn;
next = chain->next;
if (!CALL_P (insn)
|| find_reg_note (insn, REG_NORETURN, NULL))
continue;
REG_SET_TO_HARD_REG_SET (hard_regs_to_save,
&chain->live_throughout);
COPY_HARD_REG_SET (used_regs, call_used_reg_set);
/* Record all registers set in this call insn. These don't
need to be saved. N.B. the call insn might set a subreg
of a multi-hard-reg pseudo; then the pseudo is considered
live during the call, but the subreg that is set
isn't. */
CLEAR_HARD_REG_SET (this_insn_sets);
note_stores (PATTERN (insn), mark_set_regs, &this_insn_sets);
/* Sibcalls are considered to set the return value,
compare df-scan.c:df_get_call_refs. */
if (SIBLING_CALL_P (insn) && crtl->return_rtx)
mark_set_regs (crtl->return_rtx, NULL_RTX, &this_insn_sets);
AND_COMPL_HARD_REG_SET (used_regs, call_fixed_reg_set);
AND_COMPL_HARD_REG_SET (used_regs, this_insn_sets);
AND_HARD_REG_SET (hard_regs_to_save, used_regs);
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
if (TEST_HARD_REG_BIT (hard_regs_to_save, regno))
{
gcc_assert (hard_reg_map[regno] != NULL);
call_saved_regs[call_saved_regs_num++] = hard_reg_map[regno];
}
/* Look through all live pseudos, mark their hard registers. */
EXECUTE_IF_SET_IN_REG_SET
(&chain->live_throughout, FIRST_PSEUDO_REGISTER, regno, rsi)
{
int r = reg_renumber[regno];
int bound;
if (r < 0)
continue;
bound = r + hard_regno_nregs[r][PSEUDO_REGNO_MODE (regno)];
for (; r < bound; r++)
if (TEST_HARD_REG_BIT (used_regs, r))
call_saved_regs[call_saved_regs_num++] = hard_reg_map[r];
}
for (i = 0; i < call_saved_regs_num; i++)
{
saved_reg = call_saved_regs[i];
for (j = 0; j < call_saved_regs_num; j++)
if (i != j)
{
saved_reg2 = call_saved_regs[j];
saved_reg_conflicts[saved_reg->num * saved_regs_num
+ saved_reg2->num]
= saved_reg_conflicts[saved_reg2->num * saved_regs_num
+ saved_reg->num]
= TRUE;
}
}
}
/* Sort saved hard regs. */
qsort (all_saved_regs, saved_regs_num, sizeof (struct saved_hard_reg *),
saved_hard_reg_compare_func);
/* Initiate slots available from the previous reload
iteration. */
prev_save_slots_num = save_slots_num;
memcpy (prev_save_slots, save_slots, save_slots_num * sizeof (rtx));
save_slots_num = 0;
/* Allocate stack slots for the saved hard registers. */
for (i = 0; i < saved_regs_num; i++)
{
saved_reg = all_saved_regs[i];
regno = saved_reg->hard_regno;
for (j = 0; j < i; j++)
{
saved_reg2 = all_saved_regs[j];
if (! saved_reg2->first_p)
continue;
slot = saved_reg2->slot;
for (k = j; k >= 0; k = next_k)
{
saved_reg3 = all_saved_regs[k];
next_k = saved_reg3->next;
if (saved_reg_conflicts[saved_reg->num * saved_regs_num
+ saved_reg3->num])
break;
}
if (k < 0
&& (GET_MODE_SIZE (regno_save_mode[regno][1])
<= GET_MODE_SIZE (regno_save_mode
[saved_reg2->hard_regno][1])))
{
saved_reg->slot
= adjust_address_nv
(slot, regno_save_mode[saved_reg->hard_regno][1], 0);
regno_save_mem[regno][1] = saved_reg->slot;
saved_reg->next = saved_reg2->next;
saved_reg2->next = i;
if (dump_file != NULL)
fprintf (dump_file, "%d uses slot of %d\n",
regno, saved_reg2->hard_regno);
break;
}
}
if (j == i)
{
saved_reg->first_p = TRUE;
for (best_slot_num = -1, j = 0; j < prev_save_slots_num; j++)
{
slot = prev_save_slots[j];
if (slot == NULL_RTX)
continue;
if (GET_MODE_SIZE (regno_save_mode[regno][1])
<= GET_MODE_SIZE (GET_MODE (slot))
&& best_slot_num < 0)
best_slot_num = j;
if (GET_MODE (slot) == regno_save_mode[regno][1])
break;
}
if (best_slot_num >= 0)
{
saved_reg->slot = prev_save_slots[best_slot_num];
saved_reg->slot
= adjust_address_nv
(saved_reg->slot,
regno_save_mode[saved_reg->hard_regno][1], 0);
if (dump_file != NULL)
fprintf (dump_file,
"%d uses a slot from prev iteration\n", regno);
prev_save_slots[best_slot_num] = NULL_RTX;
if (best_slot_num + 1 == prev_save_slots_num)
prev_save_slots_num--;
}
else
{
saved_reg->slot
= assign_stack_local_1
(regno_save_mode[regno][1],
GET_MODE_SIZE (regno_save_mode[regno][1]), 0,
ASLK_REDUCE_ALIGN);
if (dump_file != NULL)
fprintf (dump_file, "%d uses a new slot\n", regno);
}
regno_save_mem[regno][1] = saved_reg->slot;
save_slots[save_slots_num++] = saved_reg->slot;
}
}
free (saved_reg_conflicts);
finish_saved_hard_regs ();
}
else
{
/* We are not sharing slots.
Run through all the call-used hard-registers and allocate
space for each in the caller-save area. Try to allocate space
in a manner which allows multi-register saves/restores to be done. */
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
for (j = MOVE_MAX_WORDS; j > 0; j--)
{
int do_save = 1;
/* If no mode exists for this size, try another. Also break out
if we have already saved this hard register. */
if (regno_save_mode[i][j] == VOIDmode || regno_save_mem[i][1] != 0)
continue;
/* See if any register in this group has been saved. */
for (k = 0; k < j; k++)
if (regno_save_mem[i + k][1])
{
do_save = 0;
break;
}
if (! do_save)
continue;
for (k = 0; k < j; k++)
if (! TEST_HARD_REG_BIT (hard_regs_used, i + k))
{
do_save = 0;
break;
}
if (! do_save)
continue;
/* We have found an acceptable mode to store in. Since
hard register is always saved in the widest mode
available, the mode may be wider than necessary, it is
OK to reduce the alignment of spill space. We will
verify that it is equal to or greater than required
when we restore and save the hard register in
insert_restore and insert_save. */
regno_save_mem[i][j]
= assign_stack_local_1 (regno_save_mode[i][j],
GET_MODE_SIZE (regno_save_mode[i][j]),
0, ASLK_REDUCE_ALIGN);
/* Setup single word save area just in case... */
for (k = 0; k < j; k++)
/* This should not depend on WORDS_BIG_ENDIAN.
The order of words in regs is the same as in memory. */
regno_save_mem[i + k][1]
= adjust_address_nv (regno_save_mem[i][j],
regno_save_mode[i + k][1],
k * UNITS_PER_WORD);
}
}
/* Now loop again and set the alias set of any save areas we made to
the alias set used to represent frame objects. */
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
for (j = MOVE_MAX_WORDS; j > 0; j--)
if (regno_save_mem[i][j] != 0)
set_mem_alias_set (regno_save_mem[i][j], get_frame_alias_set ());
}
/* Find the places where hard regs are live across calls and save them. */
void
save_call_clobbered_regs (void)
{
struct insn_chain *chain, *next, *last = NULL;
enum machine_mode save_mode [FIRST_PSEUDO_REGISTER];
/* Computed in mark_set_regs, holds all registers set by the current
instruction. */
HARD_REG_SET this_insn_sets;
CLEAR_HARD_REG_SET (hard_regs_saved);
n_regs_saved = 0;
for (chain = reload_insn_chain; chain != 0; chain = next)
{
rtx insn = chain->insn;
enum rtx_code code = GET_CODE (insn);
next = chain->next;
gcc_assert (!chain->is_caller_save_insn);
if (NONDEBUG_INSN_P (insn))
{
/* If some registers have been saved, see if INSN references
any of them. We must restore them before the insn if so. */
if (n_regs_saved)
{
int regno;
HARD_REG_SET this_insn_sets;
if (code == JUMP_INSN)
/* Restore all registers if this is a JUMP_INSN. */
COPY_HARD_REG_SET (referenced_regs, hard_regs_saved);
else
{
CLEAR_HARD_REG_SET (referenced_regs);
mark_referenced_regs (&PATTERN (insn),
mark_reg_as_referenced, NULL);
AND_HARD_REG_SET (referenced_regs, hard_regs_saved);
}
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
if (TEST_HARD_REG_BIT (referenced_regs, regno))
regno += insert_restore (chain, 1, regno, MOVE_MAX_WORDS,
save_mode);
/* If a saved register is set after the call, this means we no
longer should restore it. This can happen when parts of a
multi-word pseudo do not conflict with other pseudos, so
IRA may allocate the same hard register for both. One may
be live across the call, while the other is set
afterwards. */
CLEAR_HARD_REG_SET (this_insn_sets);
note_stores (PATTERN (insn), mark_set_regs, &this_insn_sets);
AND_COMPL_HARD_REG_SET (hard_regs_saved, this_insn_sets);
}
if (code == CALL_INSN
&& ! SIBLING_CALL_P (insn)
&& ! find_reg_note (insn, REG_NORETURN, NULL))
{
unsigned regno;
HARD_REG_SET hard_regs_to_save;
reg_set_iterator rsi;
/* Use the register life information in CHAIN to compute which
regs are live during the call. */
REG_SET_TO_HARD_REG_SET (hard_regs_to_save,
&chain->live_throughout);
/* Save hard registers always in the widest mode available. */
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
if (TEST_HARD_REG_BIT (hard_regs_to_save, regno))
save_mode [regno] = regno_save_mode [regno][1];
else
save_mode [regno] = VOIDmode;
/* Look through all live pseudos, mark their hard registers
and choose proper mode for saving. */
EXECUTE_IF_SET_IN_REG_SET
(&chain->live_throughout, FIRST_PSEUDO_REGISTER, regno, rsi)
{
int r = reg_renumber[regno];
int nregs;
enum machine_mode mode;
if (r < 0)
continue;
nregs = hard_regno_nregs[r][PSEUDO_REGNO_MODE (regno)];
mode = HARD_REGNO_CALLER_SAVE_MODE
(r, nregs, PSEUDO_REGNO_MODE (regno));
if (GET_MODE_BITSIZE (mode)
> GET_MODE_BITSIZE (save_mode[r]))
save_mode[r] = mode;
while (nregs-- > 0)
SET_HARD_REG_BIT (hard_regs_to_save, r + nregs);
}
/* Record all registers set in this call insn. These don't need
to be saved. N.B. the call insn might set a subreg of a
multi-hard-reg pseudo; then the pseudo is considered live
during the call, but the subreg that is set isn't. */
CLEAR_HARD_REG_SET (this_insn_sets);
note_stores (PATTERN (insn), mark_set_regs, &this_insn_sets);
/* Compute which hard regs must be saved before this call. */
AND_COMPL_HARD_REG_SET (hard_regs_to_save, call_fixed_reg_set);
AND_COMPL_HARD_REG_SET (hard_regs_to_save, this_insn_sets);
AND_COMPL_HARD_REG_SET (hard_regs_to_save, hard_regs_saved);
AND_HARD_REG_SET (hard_regs_to_save, call_used_reg_set);
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
if (TEST_HARD_REG_BIT (hard_regs_to_save, regno))
regno += insert_save (chain, 1, regno, &hard_regs_to_save, save_mode);
/* Must recompute n_regs_saved. */
n_regs_saved = 0;
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
if (TEST_HARD_REG_BIT (hard_regs_saved, regno))
n_regs_saved++;
}
last = chain;
}
else if (DEBUG_INSN_P (insn) && n_regs_saved)
mark_referenced_regs (&PATTERN (insn),
replace_reg_with_saved_mem,
save_mode);
if (chain->next == 0 || chain->next->block != chain->block)
{
int regno;
/* At the end of the basic block, we must restore any registers that
remain saved. If the last insn in the block is a JUMP_INSN, put
the restore before the insn, otherwise, put it after the insn. */
if (n_regs_saved
&& DEBUG_INSN_P (insn)
&& last
&& last->block == chain->block)
{
rtx ins, prev;
basic_block bb = BLOCK_FOR_INSN (insn);
/* When adding hard reg restores after a DEBUG_INSN, move
all notes between last real insn and this DEBUG_INSN after
the DEBUG_INSN, otherwise we could get code
-g/-g0 differences. */
for (ins = PREV_INSN (insn); ins != last->insn; ins = prev)
{
prev = PREV_INSN (ins);
if (NOTE_P (ins))
{
NEXT_INSN (prev) = NEXT_INSN (ins);
PREV_INSN (NEXT_INSN (ins)) = prev;
PREV_INSN (ins) = insn;
NEXT_INSN (ins) = NEXT_INSN (insn);
NEXT_INSN (insn) = ins;
if (NEXT_INSN (ins))
PREV_INSN (NEXT_INSN (ins)) = ins;
if (BB_END (bb) == insn)
BB_END (bb) = ins;
}
else
gcc_assert (DEBUG_INSN_P (ins));
}
}
last = NULL;
if (n_regs_saved)
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
if (TEST_HARD_REG_BIT (hard_regs_saved, regno))
regno += insert_restore (chain, JUMP_P (insn),
regno, MOVE_MAX_WORDS, save_mode);
}
}
}
/* Here from note_stores, or directly from save_call_clobbered_regs, when
an insn stores a value in a register.
Set the proper bit or bits in this_insn_sets. All pseudos that have
been assigned hard regs have had their register number changed already,
so we can ignore pseudos. */
static void
mark_set_regs (rtx reg, const_rtx setter ATTRIBUTE_UNUSED, void *data)
{
int regno, endregno, i;
HARD_REG_SET *this_insn_sets = (HARD_REG_SET *) data;
if (GET_CODE (reg) == SUBREG)
{
rtx inner = SUBREG_REG (reg);
if (!REG_P (inner) || REGNO (inner) >= FIRST_PSEUDO_REGISTER)
return;
regno = subreg_regno (reg);
endregno = regno + subreg_nregs (reg);
}
else if (REG_P (reg)
&& REGNO (reg) < FIRST_PSEUDO_REGISTER)
{
regno = REGNO (reg);
endregno = END_HARD_REGNO (reg);
}
else
return;
for (i = regno; i < endregno; i++)
SET_HARD_REG_BIT (*this_insn_sets, i);
}
/* Here from note_stores when an insn stores a value in a register.
Set the proper bit or bits in the passed regset. All pseudos that have
been assigned hard regs have had their register number changed already,
so we can ignore pseudos. */
static void
add_stored_regs (rtx reg, const_rtx setter, void *data)
{
int regno, endregno, i;
enum machine_mode mode = GET_MODE (reg);
int offset = 0;
if (GET_CODE (setter) == CLOBBER)
return;
if (GET_CODE (reg) == SUBREG
&& REG_P (SUBREG_REG (reg))
&& REGNO (SUBREG_REG (reg)) < FIRST_PSEUDO_REGISTER)
{
offset = subreg_regno_offset (REGNO (SUBREG_REG (reg)),
GET_MODE (SUBREG_REG (reg)),
SUBREG_BYTE (reg),
GET_MODE (reg));
regno = REGNO (SUBREG_REG (reg)) + offset;
endregno = regno + subreg_nregs (reg);
}
else
{
if (!REG_P (reg) || REGNO (reg) >= FIRST_PSEUDO_REGISTER)
return;
regno = REGNO (reg) + offset;
endregno = end_hard_regno (mode, regno);
}
for (i = regno; i < endregno; i++)
SET_REGNO_REG_SET ((regset) data, i);
}
/* Walk X and record all referenced registers in REFERENCED_REGS. */
static void
mark_referenced_regs (rtx *loc, refmarker_fn *mark, void *arg)
{
enum rtx_code code = GET_CODE (*loc);
const char *fmt;
int i, j;
if (code == SET)
mark_referenced_regs (&SET_SRC (*loc), mark, arg);
if (code == SET || code == CLOBBER)
{
loc = &SET_DEST (*loc);
code = GET_CODE (*loc);
if ((code == REG && REGNO (*loc) < FIRST_PSEUDO_REGISTER)
|| code == PC || code == CC0
|| (code == SUBREG && REG_P (SUBREG_REG (*loc))
&& REGNO (SUBREG_REG (*loc)) < FIRST_PSEUDO_REGISTER
/* If we're setting only part of a multi-word register,
we shall mark it as referenced, because the words
that are not being set should be restored. */