int first_save_gpr;
int first_restore_gpr;
int last_save_gpr;
+ int last_restore_gpr;
/* Size of stack frame. */
HOST_WIDE_INT frame_size;
static void replace_ltrel_base (rtx *, rtx);
static void s390_optimize_prolog (bool);
static int find_unused_clobbered_reg (void);
-static void s390_frame_info (void);
+static void s390_frame_info (int, int);
static rtx save_fpr (rtx, int, int);
static rtx restore_fpr (rtx, int, int);
static rtx save_gprs (rtx, int, int, int);
static void
s390_optimize_prolog (bool base_used)
{
- int save_first, save_last, restore_first, restore_last;
- int i, j;
rtx insn, new_insn, next_insn;
- /* Recompute regs_ever_live data for special registers. */
+ /* Do a final recompute of the frame-related data. */
+
+ s390_frame_info (base_used, cfun->machine->save_return_addr_p);
regs_ever_live[BASE_REGISTER] = base_used;
regs_ever_live[RETURN_REGNUM] = cfun->machine->save_return_addr_p;
regs_ever_live[STACK_POINTER_REGNUM] = cfun->machine->frame_size > 0;
-
- /* Find first and last gpr to be saved. */
-
- for (i = 6; i < 16; i++)
- if (regs_ever_live[i])
- if (!global_regs[i]
- || i == STACK_POINTER_REGNUM
- || i == RETURN_REGNUM
- || i == BASE_REGISTER
- || (flag_pic && i == (int)PIC_OFFSET_TABLE_REGNUM))
- break;
-
- for (j = 15; j > i; j--)
- if (regs_ever_live[j])
- if (!global_regs[j]
- || j == STACK_POINTER_REGNUM
- || j == RETURN_REGNUM
- || j == BASE_REGISTER
- || (flag_pic && j == (int)PIC_OFFSET_TABLE_REGNUM))
- break;
-
- if (i == 16)
- {
- /* Nothing to save/restore. */
- save_first = restore_first = -1;
- save_last = restore_last = -1;
- }
- else
- {
- /* Save/restore from i to j. */
- save_first = restore_first = i;
- save_last = restore_last = j;
- }
-
- /* Varargs functions need to save gprs 2 to 6. */
- if (current_function_stdarg)
- {
- save_first = 2;
- if (save_last < 6)
- save_last = 6;
- }
-
-
/* If all special registers are in fact used, there's nothing we
can do, so no point in walking the insn list. */
- if (i <= BASE_REGISTER && j >= BASE_REGISTER
- && (TARGET_CPU_ZARCH || (i <= RETURN_REGNUM && j >= RETURN_REGNUM)))
- return;
+ if (cfun->machine->first_save_gpr <= BASE_REGISTER
+ && cfun->machine->last_save_gpr >= BASE_REGISTER
+ && (TARGET_CPU_ZARCH
+ || (cfun->machine->first_save_gpr <= RETURN_REGNUM
+ && cfun->machine->last_save_gpr >= RETURN_REGNUM)))
+ return;
/* Search for prolog/epilog insns and replace them. */
if (first > BASE_REGISTER || last < BASE_REGISTER)
continue;
- if (save_first != -1)
+ if (cfun->machine->first_save_gpr != -1)
{
- new_insn = save_gprs (base, off, save_first, save_last);
+ new_insn = save_gprs (base, off, cfun->machine->first_save_gpr,
+ cfun->machine->last_save_gpr);
new_insn = emit_insn_before (new_insn, insn);
INSN_ADDRESSES_NEW (new_insn, -1);
}
if (GET_CODE (base) != REG || off < 0)
continue;
- if (save_first != -1)
+ if (cfun->machine->first_save_gpr != -1)
{
- new_insn = save_gprs (base, off, save_first, save_last);
+ new_insn = save_gprs (base, off, cfun->machine->first_save_gpr,
+ cfun->machine->last_save_gpr);
new_insn = emit_insn_before (new_insn, insn);
INSN_ADDRESSES_NEW (new_insn, -1);
}
if (first > BASE_REGISTER || last < BASE_REGISTER)
continue;
- if (restore_first != -1)
+ if (cfun->machine->first_restore_gpr != -1)
{
- new_insn = restore_gprs (base, off, restore_first, restore_last);
+ new_insn = restore_gprs (base, off, cfun->machine->first_restore_gpr,
+ cfun->machine->last_restore_gpr);
new_insn = emit_insn_before (new_insn, insn);
INSN_ADDRESSES_NEW (new_insn, -1);
}
if (GET_CODE (base) != REG || off < 0)
continue;
- if (restore_first != -1)
+ if (cfun->machine->first_restore_gpr != -1)
{
- new_insn = restore_gprs (base, off, restore_first, restore_last);
+ new_insn = restore_gprs (base, off, cfun->machine->first_restore_gpr,
+ cfun->machine->last_restore_gpr);
new_insn = emit_insn_before (new_insn, insn);
INSN_ADDRESSES_NEW (new_insn, -1);
}
return 0;
}
-/* Fill FRAME with info about frame of current function. */
+/* Fill cfun->machine with info about frame of current function.
+ BASE_USED and RETURN_ADDR_USED specify whether we assume the
+ base and return address register will need to be saved. */
static void
-s390_frame_info (void)
+s390_frame_info (int base_used, int return_addr_used)
{
+ int live_regs[16];
int i, j;
HOST_WIDE_INT fsize = get_frame_size ();
/* Does function need to setup frame and save area. */
- if (! current_function_is_leaf
+ if (!current_function_is_leaf
|| TARGET_TPF_PROFILING
|| cfun->machine->frame_size > 0
|| current_function_calls_alloca
|| current_function_stdarg)
cfun->machine->frame_size += STARTING_FRAME_OFFSET;
- /* If we use the return register, we'll need to make sure
- it is going to be saved/restored. */
+ /* Find first and last gpr to be saved. We trust regs_ever_live
+ data, except that we don't save and restore global registers.
- if (!current_function_is_leaf
- || TARGET_TPF_PROFILING
- || regs_ever_live[RETURN_REGNUM])
- cfun->machine->save_return_addr_p = 1;
+ Also, all registers with special meaning to the compiler need
+ to be handled extra. */
- /* Find first and last gpr to be saved. Note that at this point,
- we assume the base register and -on S/390- the return register
- always need to be saved. This is done because the usage of these
- register might change even after the prolog was emitted.
- If it turns out later that we really don't need them, the
- prolog/epilog code is modified again. */
+ for (i = 0; i < 16; i++)
+ live_regs[i] = regs_ever_live[i] && !global_regs[i];
- regs_ever_live[BASE_REGISTER] = 1;
- if (!TARGET_CPU_ZARCH || cfun->machine->save_return_addr_p)
- regs_ever_live[RETURN_REGNUM] = 1;
- regs_ever_live[STACK_POINTER_REGNUM] = cfun->machine->frame_size > 0;
+ if (flag_pic)
+ live_regs[PIC_OFFSET_TABLE_REGNUM] =
+ regs_ever_live[PIC_OFFSET_TABLE_REGNUM];
- for (i = 6; i < 16; i++)
- if (regs_ever_live[i])
- if (!global_regs[i]
- || i == STACK_POINTER_REGNUM
- || i == RETURN_REGNUM
- || i == BASE_REGISTER
- || (flag_pic && i == (int)PIC_OFFSET_TABLE_REGNUM))
- break;
+ live_regs[BASE_REGISTER] = base_used;
+ live_regs[RETURN_REGNUM] = return_addr_used;
+ live_regs[STACK_POINTER_REGNUM] = cfun->machine->frame_size > 0;
+ for (i = 6; i < 16; i++)
+ if (live_regs[i])
+ break;
for (j = 15; j > i; j--)
- if (regs_ever_live[j])
- if (!global_regs[j]
- || j == STACK_POINTER_REGNUM
- || j == RETURN_REGNUM
- || j == BASE_REGISTER
- || (flag_pic && j == (int)PIC_OFFSET_TABLE_REGNUM))
- break;
+ if (live_regs[j])
+ break;
- /* Save / Restore from gpr i to j. */
- cfun->machine->first_save_gpr = i;
- cfun->machine->first_restore_gpr = i;
- cfun->machine->last_save_gpr = j;
+ if (i == 16)
+ {
+ /* Nothing to save/restore. */
+ cfun->machine->first_save_gpr = -1;
+ cfun->machine->first_restore_gpr = -1;
+ cfun->machine->last_save_gpr = -1;
+ cfun->machine->last_restore_gpr = -1;
+ }
+ else
+ {
+ /* Save / Restore from gpr i to j. */
+ cfun->machine->first_save_gpr = i;
+ cfun->machine->first_restore_gpr = i;
+ cfun->machine->last_save_gpr = j;
+ cfun->machine->last_restore_gpr = j;
+ }
/* Varargs functions need to save gprs 2 to 6. */
if (current_function_stdarg)
- cfun->machine->first_save_gpr = 2;
+ {
+ if (cfun->machine->first_save_gpr == -1
+ || cfun->machine->first_save_gpr > 2)
+ cfun->machine->first_save_gpr = 2;
+
+ if (cfun->machine->last_save_gpr == -1
+ || cfun->machine->last_save_gpr < 6)
+ cfun->machine->last_save_gpr = 6;
+ }
}
/* Return offset between argument pointer and frame pointer
HOST_WIDE_INT
s390_arg_frame_offset (void)
{
- HOST_WIDE_INT fsize = get_frame_size ();
- int save_fprs_p, i;
+ /* See the comment in s390_emit_prologue about the assumptions we make
+ whether or not the base and return address register need to be saved. */
+ int return_addr_used = !current_function_is_leaf
+ || TARGET_TPF_PROFILING
+ || regs_ever_live[RETURN_REGNUM]
+ || cfun->machine->save_return_addr_p;
- /* fprs 8 - 15 are caller saved for 64 Bit ABI. */
- save_fprs_p = 0;
- if (TARGET_64BIT)
- for (i = 24; i < 32; i++)
- if (regs_ever_live[i] && !global_regs[i])
- {
- save_fprs_p = 1;
- break;
- }
-
- fsize = fsize + save_fprs_p * 64;
-
- /* Does function need to setup frame and save area. */
-
- if (! current_function_is_leaf
- || TARGET_TPF_PROFILING
- || fsize > 0
- || current_function_calls_alloca
- || current_function_stdarg)
- fsize += STARTING_FRAME_OFFSET;
- return fsize + STACK_POINTER_OFFSET;
+ s390_frame_info (1, !TARGET_CPU_ZARCH || return_addr_used);
+ return cfun->machine->frame_size + STACK_POINTER_OFFSET;
}
/* Emit insn to save fpr REGNUM at offset OFFSET relative
rtx temp_reg;
int i;
- /* Compute frame_info. */
+ /* At this point, we decide whether we'll need to save/restore the
+ return address register. This decision is final on zSeries machines;
+ on S/390 it can still be overridden in s390_split_branches. */
+
+ if (!current_function_is_leaf
+ || TARGET_TPF_PROFILING
+ || regs_ever_live[RETURN_REGNUM])
+ cfun->machine->save_return_addr_p = 1;
+
+ /* Compute frame info. Note that at this point, we assume the base
+ register and -on S/390- the return register always need to be saved.
+ This is done because the usage of these registers might change even
+ after the prolog was emitted. If it turns out later that we really
+ don't need them, the prolog/epilog code is modified again. */
- s390_frame_info ();
+ s390_frame_info (1, !TARGET_CPU_ZARCH || cfun->machine->save_return_addr_p);
+
+ /* We need to update regs_ever_live to avoid data-flow problems. */
+
+ regs_ever_live[BASE_REGISTER] = 1;
+ regs_ever_live[RETURN_REGNUM] = !TARGET_CPU_ZARCH
+ || cfun->machine->save_return_addr_p;
+ regs_ever_live[STACK_POINTER_REGNUM] = cfun->machine->frame_size > 0;
/* Choose best register to use for temp use within prologue.
See below for why TPF must use the register 1. */
if (cfun->machine->first_restore_gpr != -1)
{
area_bottom = cfun->machine->first_restore_gpr * UNITS_PER_WORD;
- area_top = (cfun->machine->last_save_gpr + 1) * UNITS_PER_WORD;
+ area_top = (cfun->machine->last_restore_gpr + 1) * UNITS_PER_WORD;
}
else
{
to stack location from where they get restored. */
for (i = cfun->machine->first_restore_gpr;
- i <= cfun->machine->last_save_gpr;
+ i <= cfun->machine->last_restore_gpr;
i++)
{
/* These registers are special and need to be
if (cfun->machine->save_return_addr_p
|| (cfun->machine->first_restore_gpr < BASE_REGISTER
- && cfun->machine->last_save_gpr > RETURN_REGNUM))
+ && cfun->machine->last_restore_gpr > RETURN_REGNUM))
{
int return_regnum = find_unused_clobbered_reg();
if (!return_regnum)
insn = restore_gprs (frame_pointer, offset,
cfun->machine->first_restore_gpr,
- cfun->machine->last_save_gpr);
+ cfun->machine->last_restore_gpr);
emit_insn (insn);
}
projects / gcc.git / commitdiff