static void ix86_mark_machine_status PARAMS ((struct function *));
static void ix86_split_to_parts PARAMS ((rtx, rtx *, enum machine_mode));
static int ix86_safe_length_prefix PARAMS ((rtx));
+static HOST_WIDE_INT ix86_compute_frame_size PARAMS((HOST_WIDE_INT, int *));
+static int ix86_nsaved_regs PARAMS((void));
+static void ix86_emit_save_regs PARAMS((void));
+static void ix86_emit_restore_regs PARAMS((void));
+static void ix86_emit_epilogue_esp_adjustment PARAMS((int));
struct ix86_address
{
int
ix86_can_use_return_insn_p ()
{
- int regno;
- int nregs = 0;
- int reglimit = (frame_pointer_needed
- ? FRAME_POINTER_REGNUM : STACK_POINTER_REGNUM);
- int pic_reg_used = flag_pic && (current_function_uses_pic_offset_table
- || current_function_uses_const_pool);
-
#ifdef NON_SAVING_SETJMP
if (NON_SAVING_SETJMP && current_function_calls_setjmp)
return 0;
if (! reload_completed)
return 0;
- for (regno = reglimit - 1; regno >= 0; regno--)
- if ((regs_ever_live[regno] && ! call_used_regs[regno])
- || (regno == PIC_OFFSET_TABLE_REGNUM && pic_reg_used))
- nregs++;
-
- return nregs == 0 || ! frame_pointer_needed;
+ return ix86_nsaved_regs () == 0 || ! frame_pointer_needed;
}
\f
static char *pic_label_name;
arg);
}
+/* Return number of registers to be saved on the stack. */
+
+static int
+ix86_nsaved_regs ()
+{
+ int nregs = 0;
+ int pic_reg_used = flag_pic && (current_function_uses_pic_offset_table
+ || current_function_uses_const_pool);
+ int limit = (frame_pointer_needed
+ ? HARD_FRAME_POINTER_REGNUM : STACK_POINTER_REGNUM);
+ int regno;
+
+ for (regno = limit - 1; regno >= 0; regno--)
+ if ((regs_ever_live[regno] && ! call_used_regs[regno])
+ || (regno == PIC_OFFSET_TABLE_REGNUM && pic_reg_used))
+ {
+ nregs ++;
+ }
+ return nregs;
+}
+
+/* Return the offset between two registers, one to be eliminated, and the other
+ its replacement, at the start of a routine. */
+
+HOST_WIDE_INT
+ix86_initial_elimination_offset (from, to)
+ int from;
+ int to;
+{
+ if (from == ARG_POINTER_REGNUM && to == FRAME_POINTER_REGNUM)
+ return 8; /* Skip saved PC and previous frame pointer */
+ else
+ {
+ int nregs;
+ int poffset;
+ int offset;
+ int preferred_alignment = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
+ HOST_WIDE_INT tsize = ix86_compute_frame_size (get_frame_size (),
+ &nregs);
+
+ offset = (tsize + nregs * UNITS_PER_WORD);
+
+ poffset = 4;
+ if (frame_pointer_needed)
+ poffset += UNITS_PER_WORD;
+
+ if (from == ARG_POINTER_REGNUM)
+ offset += poffset;
+ else
+ offset -= ((poffset + preferred_alignment - 1)
+ & -preferred_alignment) - poffset;
+ return offset;
+ }
+}
+
/* Compute the size of local storage taking into consideration the
desired stack alignment which is to be maintained. Also determine
the number of registers saved below the local storage. */
return size + padding;
}
+/* Emit code to save registers in the prologue. */
+
+static void
+ix86_emit_save_regs ()
+{
+ register int regno;
+ int limit;
+ rtx insn;
+ int pic_reg_used = flag_pic && (current_function_uses_pic_offset_table
+ || current_function_uses_const_pool);
+ limit = (frame_pointer_needed
+ ? FRAME_POINTER_REGNUM : STACK_POINTER_REGNUM);
+
+ for (regno = limit - 1; regno >= 0; regno--)
+ if ((regs_ever_live[regno] && !call_used_regs[regno])
+ || (regno == PIC_OFFSET_TABLE_REGNUM && pic_reg_used))
+ {
+ insn = emit_insn (gen_push (gen_rtx_REG (SImode, regno)));
+ RTX_FRAME_RELATED_P (insn) = 1;
+ }
+}
+
/* Expand the prologue into a bunch of separate insns. */
void
ix86_expand_prologue ()
{
- register int regno;
- int limit;
int pic_reg_used = flag_pic && (current_function_uses_pic_offset_table
|| current_function_uses_const_pool);
HOST_WIDE_INT tsize = ix86_compute_frame_size (get_frame_size (), (int *)0);
CALL_INSN_FUNCTION_USAGE (insn));
}
- limit = (frame_pointer_needed ? FRAME_POINTER_REGNUM : STACK_POINTER_REGNUM);
- for (regno = limit - 1; regno >= 0; regno--)
- if ((regs_ever_live[regno] && ! call_used_regs[regno])
- || (regno == PIC_OFFSET_TABLE_REGNUM && pic_reg_used))
- {
- insn = emit_insn (gen_push (gen_rtx_REG (SImode, regno)));
- RTX_FRAME_RELATED_P (insn) = 1;
- }
-
+ ix86_emit_save_regs ();
#ifdef SUBTARGET_PROLOGUE
SUBTARGET_PROLOGUE;
#endif
emit_insn (gen_blockage ());
}
+/* Emit code to pop all registers from stack. */
+
+static void
+ix86_emit_restore_regs ()
+{
+ int pic_reg_used = flag_pic && (current_function_uses_pic_offset_table
+ || current_function_uses_const_pool);
+ int limit = (frame_pointer_needed
+ ? FRAME_POINTER_REGNUM : STACK_POINTER_REGNUM);
+ int regno;
+
+ for (regno = 0; regno < limit; regno++)
+ if ((regs_ever_live[regno] && !call_used_regs[regno])
+ || (regno == PIC_OFFSET_TABLE_REGNUM && pic_reg_used))
+ {
+ emit_insn (gen_popsi1 (gen_rtx_REG (SImode, regno)));
+ }
+}
+
+/* Emit code to add TSIZE to esp value. Use POP instruction when
+ profitable. */
+
+static void
+ix86_emit_epilogue_esp_adjustment (tsize)
+ int tsize;
+{
+ /* Intel's docs say that for 4 or 8 bytes of stack frame one should
+ use `pop' and not `add'. */
+ int use_pop = tsize == 4;
+ rtx edx = 0, ecx;
+
+ /* Use two pops only for the Pentium processors. */
+ if (tsize == 8 && !TARGET_386 && !TARGET_486)
+ {
+ rtx retval = current_function_return_rtx;
+
+ edx = gen_rtx_REG (SImode, 1);
+
+ /* This case is a bit more complex. Since we cannot pop into
+ %ecx twice we need a second register. But this is only
+ available if the return value is not of DImode in which
+ case the %edx register is not available. */
+ use_pop = (retval == NULL
+ || !reg_overlap_mentioned_p (edx, retval));
+ }
+
+ if (use_pop)
+ {
+ ecx = gen_rtx_REG (SImode, 2);
+
+ /* We have to prevent the two pops here from being scheduled.
+ GCC otherwise would try in some situation to put other
+ instructions in between them which has a bad effect. */
+ emit_insn (gen_blockage ());
+ emit_insn (gen_popsi1 (ecx));
+ if (tsize == 8)
+ emit_insn (gen_popsi1 (edx));
+ }
+ else
+ {
+ /* If there is no frame pointer, we must still release the frame. */
+ emit_insn (gen_addsi3 (stack_pointer_rtx, stack_pointer_rtx,
+ GEN_INT (tsize)));
+ }
+}
+
/* Restore function stack, frame, and registers. */
void
ix86_expand_epilogue ()
{
- register int regno;
- register int limit;
+ int regno;
int nregs;
+ int limit;
int pic_reg_used = flag_pic && (current_function_uses_pic_offset_table
|| current_function_uses_const_pool);
int sp_valid = !frame_pointer_needed || current_function_sp_is_unchanging;
less work than reloading sp and popping the register. Otherwise,
restore sp (if necessary) and pop the registers. */
- limit = (frame_pointer_needed
- ? FRAME_POINTER_REGNUM : STACK_POINTER_REGNUM);
-
if (nregs > 1 || sp_valid)
{
if ( !sp_valid )
emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx, addr_offset));
}
- for (regno = 0; regno < limit; regno++)
- if ((regs_ever_live[regno] && ! call_used_regs[regno])
- || (regno == PIC_OFFSET_TABLE_REGNUM && pic_reg_used))
- {
- emit_insn (gen_popsi1 (gen_rtx_REG (SImode, regno)));
- }
+ ix86_emit_restore_regs ();
}
else
{
+ limit = (frame_pointer_needed
+ ? FRAME_POINTER_REGNUM : STACK_POINTER_REGNUM);
for (regno = 0; regno < limit; regno++)
if ((regs_ever_live[regno] && ! call_used_regs[regno])
|| (regno == PIC_OFFSET_TABLE_REGNUM && pic_reg_used))
}
}
else if (tsize)
- {
- /* Intel's docs say that for 4 or 8 bytes of stack frame one should
- use `pop' and not `add'. */
- int use_pop = tsize == 4;
- rtx edx = 0, ecx;
-
- /* Use two pops only for the Pentium processors. */
- if (tsize == 8 && !TARGET_386 && !TARGET_486)
- {
- rtx retval = current_function_return_rtx;
-
- edx = gen_rtx_REG (SImode, 1);
-
- /* This case is a bit more complex. Since we cannot pop into
- %ecx twice we need a second register. But this is only
- available if the return value is not of DImode in which
- case the %edx register is not available. */
- use_pop = (retval == NULL
- || ! reg_overlap_mentioned_p (edx, retval));
- }
-
- if (use_pop)
- {
- ecx = gen_rtx_REG (SImode, 2);
-
- /* We have to prevent the two pops here from being scheduled.
- GCC otherwise would try in some situation to put other
- instructions in between them which has a bad effect. */
- emit_insn (gen_blockage ());
- emit_insn (gen_popsi1 (ecx));
- if (tsize == 8)
- emit_insn (gen_popsi1 (edx));
- }
- else
- {
- /* If there is no frame pointer, we must still release the frame. */
- emit_insn (gen_addsi3 (stack_pointer_rtx, stack_pointer_rtx,
- GEN_INT (tsize)));
- }
- }
+ ix86_emit_epilogue_esp_adjustment (tsize);
#ifdef FUNCTION_BLOCK_PROFILER_EXIT
if (profile_block_flag == 2)
projects / platform / upstream / gcc.git / commitdiff