[PATCH] S/390: Determine clobbered regs in a function - take 2
Andreas Krebbel
krebbel1@de.ibm.com
Tue Jun 28 08:37:00 GMT 2005
Hi,
Ulrich has reviewed my patch offline.
I've fixed few minor flaws and coding style issues. And of course I've
added the DONE; to the exception_receiver expander - thanks to rth.
Bootstrapped on s390 and s390x - no testsuite regressions.
OK for mainline?
Bye,
-Andreas-
2005-06-28 Andreas Krebbel <krebbel1@de.ibm.com>
* config/s390/s390.c (machine_function): New field has_landing_pad_p.
(s390_set_has_landing_pad_p, s390_reg_clobbered_rtx,
s390_regs_ever_clobbered): New functions.
(s390_return_addr_rtx): Use get_hard_reg_initial_value.
(s390_register_info, s390_init_frame_layout, s390_update_frame_layout):
Use s390_regs_ever_clobbered.
(s390_emit_prologue): Don't use r14 as temp reg if its content is used
for builtin_return_address.
* config/s390/s390.md ("exception_receiver"): New expander.
* config/s390/s390-protos.h (s390_set_has_landing_pad_p): Prototype
added.
Index: gcc/config/s390/s390-protos.h
===================================================================
--- gcc/config/s390/s390-protos.h.orig 2005-06-28 09:01:49.000000000 +0200
+++ gcc/config/s390/s390-protos.h 2005-06-28 09:02:03.000000000 +0200
@@ -29,6 +29,7 @@ extern void s390_emit_prologue (void);
extern void s390_emit_epilogue (bool);
extern void s390_function_profiler (FILE *, int);
extern void s390_conditional_register_usage (void);
+extern void s390_set_has_landing_pad_p (bool);
#ifdef RTX_CODE
extern int s390_extra_constraint_str (rtx, int, const char *);
Index: gcc/config/s390/s390.c
===================================================================
--- gcc/config/s390/s390.c.orig 2005-06-28 09:01:49.000000000 +0200
+++ gcc/config/s390/s390.c 2005-06-28 09:50:10.000000000 +0200
@@ -245,6 +245,8 @@ struct machine_function GTY(())
/* Some local-dynamic TLS symbol name. */
const char *some_ld_name;
+
+ bool has_landing_pad_p;
};
/* Few accessor macros for struct cfun->machine->s390_frame_layout. */
@@ -262,6 +264,13 @@ struct machine_function GTY(())
#define GP_ARG_NUM_REG 5
#define FP_ARG_NUM_REG (TARGET_64BIT? 4 : 2)
+/* Set the has_landing_pad_p flag in struct machine_function to VALUE. */
+
+void
+s390_set_has_landing_pad_p (bool value)
+{
+ cfun->machine->has_landing_pad_p = value;
+}
/* Return true if SET either doesn't set the CC register, or else
the source and destination have matching CC modes and that
@@ -5483,8 +5492,14 @@ s390_return_addr_rtx (int count, rtx fra
if (count == 0)
{
- cfun_frame_layout.save_return_addr_p = true;
- return gen_rtx_MEM (Pmode, return_address_pointer_rtx);
+ /* On non-z architectures branch splitting could overwrite r14. */
+ if (TARGET_CPU_ZARCH)
+ return get_hard_reg_initial_val (Pmode, RETURN_REGNUM);
+ else
+ {
+ cfun_frame_layout.save_return_addr_p = true;
+ return gen_rtx_MEM (Pmode, return_address_pointer_rtx);
+ }
}
if (TARGET_PACKED_STACK)
@@ -5531,6 +5546,88 @@ find_unused_clobbered_reg (void)
return 0;
}
+
+/* Helper function for s390_regs_ever_clobbered. Sets the fields in DATA for all
+ clobbered hard regs in SETREG. */
+
+static void
+s390_reg_clobbered_rtx (rtx setreg, rtx set_insn ATTRIBUTE_UNUSED, void *data)
+{
+ int *regs_ever_clobbered = (int*)data;
+ unsigned int i, regno;
+ enum machine_mode mode = GET_MODE (setreg);
+
+ if (GET_CODE (setreg) == SUBREG)
+ {
+ rtx inner = SUBREG_REG (setreg);
+ if (!GENERAL_REG_P (inner))
+ return;
+ regno = subreg_regno (setreg);
+ }
+ else if (GENERAL_REG_P (setreg))
+ regno = REGNO (setreg);
+ else
+ return;
+
+ for (i = regno;
+ i < regno + HARD_REGNO_NREGS (regno, mode);
+ i++)
+ regs_ever_clobbered[i] = 1;
+}
+
+/* Walks through all basic blocks of the current function looking
+ for clobbered hard regs using s390_reg_clobbered_rtx. The fields
+ of the passed integer array REGS_EVER_CLOBBERED are set to one for
+ each of those regs. */
+
+static void
+s390_regs_ever_clobbered (int *regs_ever_clobbered)
+{
+ basic_block cur_bb;
+ rtx cur_insn;
+ unsigned int i;
+
+ memset (regs_ever_clobbered, 0, 16 * sizeof (int));
+
+ /* For non-leaf functions we have to consider all call clobbered regs to be
+ clobbered. */
+ if (!current_function_is_leaf)
+ {
+ for (i = 0; i < 16; i++)
+ regs_ever_clobbered[i] = call_really_used_regs[i];
+ }
+
+ /* Make the "magic" eh_return registers live if necessary. For regs_ever_live
+ this work is done by liveness analysis (mark_regs_live_at_end).
+ Special care is needed for functions containing landing pads. Landing pads
+ may use the eh registers, but the code which sets these registers is not
+ contained in that function. Hence s390_regs_ever_clobbered is not able to
+ deal with this automatically. */
+ if (current_function_calls_eh_return || cfun->machine->has_landing_pad_p)
+ for (i = 0; EH_RETURN_DATA_REGNO (i) != INVALID_REGNUM ; i++)
+ regs_ever_clobbered[EH_RETURN_DATA_REGNO (i)] = 1;
+
+ /* For nonlocal gotos all call-saved registers have to be saved.
+ This flag is also set for the unwinding code in libgcc.
+ See expand_builtin_unwind_init. For regs_ever_live this is done by
+ reload. */
+ if (current_function_has_nonlocal_label)
+ for (i = 0; i < 16; i++)
+ if (!call_really_used_regs[i])
+ regs_ever_clobbered[i] = 1;
+
+ FOR_EACH_BB (cur_bb)
+ {
+ FOR_BB_INSNS (cur_bb, cur_insn)
+ {
+ if (INSN_P (cur_insn))
+ note_stores (PATTERN (cur_insn),
+ s390_reg_clobbered_rtx,
+ regs_ever_clobbered);
+ }
+ }
+}
+
/* Determine the frame area which actually has to be accessed
in the function epilogue. The values are stored at the
given pointers AREA_BOTTOM (address of the lowest used stack
@@ -5574,10 +5671,10 @@ s390_frame_area (int *area_bottom, int *
}
/* Fill cfun->machine with info about register usage of current function.
- Return in LIVE_REGS which GPRs are currently considered live. */
+ Return in CLOBBERED_REGS which GPRs are currently considered set. */
static void
-s390_register_info (int live_regs[])
+s390_register_info (int clobbered_regs[])
{
int i, j;
@@ -5598,34 +5695,39 @@ s390_register_info (int live_regs[])
Also, all registers with special meaning to the compiler need
to be handled extra. */
+ s390_regs_ever_clobbered (clobbered_regs);
+
for (i = 0; i < 16; i++)
- live_regs[i] = regs_ever_live[i] && !global_regs[i];
+ clobbered_regs[i] = clobbered_regs[i] && !global_regs[i];
+
+ if (frame_pointer_needed)
+ clobbered_regs[HARD_FRAME_POINTER_REGNUM] = 1;
if (flag_pic)
- live_regs[PIC_OFFSET_TABLE_REGNUM]
+ clobbered_regs[PIC_OFFSET_TABLE_REGNUM]
= regs_ever_live[PIC_OFFSET_TABLE_REGNUM];
- live_regs[BASE_REGNUM]
+ clobbered_regs[BASE_REGNUM]
= cfun->machine->base_reg
&& REGNO (cfun->machine->base_reg) == BASE_REGNUM;
- live_regs[RETURN_REGNUM]
+ clobbered_regs[RETURN_REGNUM]
= cfun->machine->split_branches_pending_p
|| cfun_frame_layout.save_return_addr_p;
- live_regs[STACK_POINTER_REGNUM]
+ clobbered_regs[STACK_POINTER_REGNUM]
= !current_function_is_leaf
|| TARGET_TPF_PROFILING
|| cfun_save_high_fprs_p
|| get_frame_size () > 0
|| current_function_calls_alloca
|| current_function_stdarg;
-
+
for (i = 6; i < 16; i++)
- if (live_regs[i])
+ if (clobbered_regs[i])
break;
for (j = 15; j > i; j--)
- if (live_regs[j])
+ if (clobbered_regs[j])
break;
if (i == 16)
@@ -5808,10 +5910,12 @@ s390_init_frame_layout (void)
{
HOST_WIDE_INT frame_size;
int base_used;
- int live_regs[16];
+ int clobbered_regs[16];
/* If return address register is explicitly used, we need to save it. */
- if (regs_ever_live[RETURN_REGNUM]
+ s390_regs_ever_clobbered (clobbered_regs);
+
+ if (clobbered_regs[RETURN_REGNUM]
|| !current_function_is_leaf
|| TARGET_TPF_PROFILING
|| current_function_stdarg
@@ -5845,7 +5949,7 @@ s390_init_frame_layout (void)
else
cfun->machine->base_reg = gen_rtx_REG (Pmode, BASE_REGNUM);
- s390_register_info (live_regs);
+ s390_register_info (clobbered_regs);
s390_frame_info ();
}
while (frame_size != cfun_frame_layout.frame_size);
@@ -5859,13 +5963,13 @@ s390_init_frame_layout (void)
static void
s390_update_frame_layout (void)
{
- int live_regs[16];
+ int clobbered_regs[16];
- s390_register_info (live_regs);
+ s390_register_info (clobbered_regs);
- regs_ever_live[BASE_REGNUM] = live_regs[BASE_REGNUM];
- regs_ever_live[RETURN_REGNUM] = live_regs[RETURN_REGNUM];
- regs_ever_live[STACK_POINTER_REGNUM] = live_regs[STACK_POINTER_REGNUM];
+ regs_ever_live[BASE_REGNUM] = clobbered_regs[BASE_REGNUM];
+ regs_ever_live[RETURN_REGNUM] = clobbered_regs[RETURN_REGNUM];
+ regs_ever_live[STACK_POINTER_REGNUM] = clobbered_regs[STACK_POINTER_REGNUM];
if (cfun->machine->base_reg)
regs_ever_live[REGNO (cfun->machine->base_reg)] = 1;
@@ -6137,7 +6241,9 @@ s390_emit_prologue (void)
/* Choose best register to use for temp use within prologue.
See below for why TPF must use the register 1. */
- if (!current_function_is_leaf && !TARGET_TPF_PROFILING)
+ if (!has_hard_reg_initial_val (Pmode, RETURN_REGNUM)
+ && !current_function_is_leaf
+ && !TARGET_TPF_PROFILING)
temp_reg = gen_rtx_REG (Pmode, RETURN_REGNUM);
else
temp_reg = gen_rtx_REG (Pmode, 1);
Index: gcc/config/s390/s390.md
===================================================================
--- gcc/config/s390/s390.md.orig 2005-06-28 09:01:49.000000000 +0200
+++ gcc/config/s390/s390.md 2005-06-28 09:02:03.000000000 +0200
@@ -6895,6 +6895,13 @@
DONE;
})
+(define_expand "exception_receiver"
+ [(const_int 0)]
+ ""
+{
+ s390_set_has_landing_pad_p (true);
+ DONE;
+})
;
; nop instruction pattern(s).
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