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4 * This file is part of libFirm.
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15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Peephole optimization and legalization of a sparc function
23 * @author Matthias Braun
26 * A note on sparc stackpointer (sp) behaviour:
27 * The ABI expects SPARC_MIN_STACKSIZE bytes to be available at the
28 * stackpointer. This space will be used to spill register windows,
29 * and for spilling va_arg arguments (maybe we can optimize this away for
30 * statically known not-va-arg-functions...)
31 * This in effect means that we allocate that extra space at the function begin
32 * which is easy. But this space isn't really fixed at the beginning of the
33 * stackframe. Instead you should rather imagine the space as always being the
34 * last-thing on the stack.
35 * So when addressing anything stack-specific we have to account for this
36 * area, while our compiler thinks the space is occupied at the beginning
37 * of the stack frame. The code here among other things adjusts these offsets
42 #include "bearch_sparc_t.h"
43 #include "gen_sparc_regalloc_if.h"
44 #include "sparc_new_nodes.h"
45 #include "sparc_transform.h"
51 #include "bepeephole.h"
54 #include "bespillslots.h"
58 static void kill_unused_stacknodes(ir_node *node)
60 if (get_irn_n_edges(node) > 0)
63 if (be_is_IncSP(node)) {
66 } else if (is_Phi(node)) {
67 int arity = get_irn_arity(node);
68 ir_node **ins = ALLOCAN(ir_node*, arity);
71 memcpy(ins, get_irn_in(node), arity*sizeof(ins[0]));
74 for (i = 0; i < arity; ++i)
75 kill_unused_stacknodes(ins[i]);
79 static void introduce_epilog(ir_node *ret)
81 const arch_register_t *sp_reg = &sparc_registers[REG_SP];
82 ir_graph *irg = get_irn_irg(ret);
83 be_stack_layout_t *layout = be_get_irg_stack_layout(irg);
84 ir_node *block = get_nodes_block(ret);
85 ir_type *frame_type = get_irg_frame_type(irg);
86 unsigned frame_size = get_type_size_bytes(frame_type);
87 int sp_idx = be_find_return_reg_input(ret, sp_reg);
88 ir_node *sp = get_irn_n(ret, sp_idx);
90 if (!layout->sp_relative) {
91 const arch_register_t *fp_reg = &sparc_registers[REG_FRAME_POINTER];
92 ir_node *fp = be_get_initial_reg_value(irg, fp_reg);
93 ir_node *restore = new_bd_sparc_RestoreZero(NULL, block, fp);
94 sched_add_before(ret, restore);
95 arch_set_irn_register(restore, sp_reg);
96 set_irn_n(ret, sp_idx, restore);
98 kill_unused_stacknodes(sp);
100 ir_node *incsp = be_new_IncSP(sp_reg, block, sp, -frame_size, 0);
101 set_irn_n(ret, sp_idx, incsp);
102 sched_add_before(ret, incsp);
106 void sparc_introduce_prolog_epilog(ir_graph *irg)
108 const arch_register_t *sp_reg = &sparc_registers[REG_SP];
109 ir_node *start = get_irg_start(irg);
110 be_stack_layout_t *layout = be_get_irg_stack_layout(irg);
111 ir_node *block = get_nodes_block(start);
112 ir_node *initial_sp = be_get_initial_reg_value(irg, sp_reg);
113 ir_node *sp = initial_sp;
114 ir_node *schedpoint = start;
115 ir_type *frame_type = get_irg_frame_type(irg);
116 unsigned frame_size = get_type_size_bytes(frame_type);
118 /* introduce epilog for every return node */
120 ir_node *end_block = get_irg_end_block(irg);
121 int arity = get_irn_arity(end_block);
124 for (i = 0; i < arity; ++i) {
125 ir_node *ret = get_irn_n(end_block, i);
126 assert(is_sparc_Return(ret));
127 introduce_epilog(ret);
131 while (be_is_Keep(sched_next(schedpoint)))
132 schedpoint = sched_next(schedpoint);
134 if (!layout->sp_relative) {
135 ir_node *save = new_bd_sparc_Save_imm(NULL, block, sp, NULL,
136 -SPARC_MIN_STACKSIZE-frame_size);
137 arch_set_irn_register(save, sp_reg);
138 sched_add_after(schedpoint, save);
141 edges_reroute(initial_sp, save);
142 set_irn_n(save, n_sparc_Save_stack, initial_sp);
144 /* we still need the Save even if noone is explicitely using the
145 * value. (TODO: this isn't 100% correct yet, something at the end of
146 * the function should hold the Save, even if we use a restore
147 * which just overrides it instead of using the value)
149 if (get_irn_n_edges(save) == 0) {
150 ir_node *in[] = { save };
151 ir_node *keep = be_new_Keep(block, 1, in);
152 sched_add_after(schedpoint, keep);
155 ir_node *incsp = be_new_IncSP(sp_reg, block, sp, frame_size, 0);
156 edges_reroute(initial_sp, incsp);
157 be_set_IncSP_pred(incsp, sp);
158 sched_add_after(schedpoint, incsp);
163 * Creates a constant from an immediate value.
165 static ir_node *create_constant_from_immediate(ir_node *node, int offset)
167 dbg_info *dbgi = get_irn_dbg_info(node);
168 ir_node *block = get_nodes_block(node);
169 ir_node *high = new_bd_sparc_SetHi(dbgi, block, NULL, offset);
171 sched_add_before(node, high);
172 arch_set_irn_register(high, &sparc_registers[REG_G4]);
174 if ((offset & 0x3ff) != 0) {
175 ir_node *low = new_bd_sparc_Or_imm(dbgi, block, high, NULL, offset & 0x3ff);
177 sched_add_before(node, low);
178 arch_set_irn_register(low, &sparc_registers[REG_G4]);
186 static void finish_sparc_Save(ir_node *node)
188 sparc_attr_t *attr = get_sparc_attr(node);
189 int offset = attr->immediate_value;
191 if (! sparc_is_value_imm_encodeable(offset)) {
192 ir_node *base = get_irn_n(node, n_sparc_Save_stack);
193 dbg_info *dbgi = get_irn_dbg_info(node);
194 ir_node *block = get_nodes_block(node);
195 ir_node *constant = create_constant_from_immediate(node, offset);
196 ir_node *new_save = new_bd_sparc_Save_reg(dbgi, block, base, constant);
197 const arch_register_t *reg = arch_get_irn_register(node);
199 /* we have a Save with immediate */
200 assert(get_irn_arity(node) == 1);
202 sched_add_before(node, new_save);
203 arch_set_irn_register(new_save, reg);
204 be_peephole_exchange(node, new_save);
209 * SPARC immediates are limited. Split IncSP with bigger immediates if
212 static void finish_be_IncSP(ir_node *node)
214 int offset = be_get_IncSP_offset(node);
216 /* we might have to break the IncSP apart if the constant has become too big */
217 if (! sparc_is_value_imm_encodeable(offset) && ! sparc_is_value_imm_encodeable(-offset)) {
218 ir_node *sp = be_get_IncSP_pred(node);
219 dbg_info *dbgi = get_irn_dbg_info(node);
220 ir_node *block = get_nodes_block(node);
221 ir_node *constant = create_constant_from_immediate(node, offset);
222 ir_node *sub = new_bd_sparc_Sub_reg(dbgi, block, sp, constant);
224 sched_add_before(node, sub);
225 arch_set_irn_register(sub, &sparc_registers[REG_SP]);
226 be_peephole_exchange(node, sub);
231 * Adjust sp-relative offsets.
233 * Split into multiple instructions if offset exceeds SPARC immediate range.
235 static void finish_sparc_FrameAddr(ir_node *node)
237 sparc_attr_t *attr = get_sparc_attr(node);
238 int offset = attr->immediate_value;
240 if (! sparc_is_value_imm_encodeable(offset)) {
241 ir_node *base = get_irn_n(node, n_sparc_FrameAddr_base);
242 dbg_info *dbgi = get_irn_dbg_info(node);
243 ir_node *block = get_nodes_block(node);
244 ir_node *constant = create_constant_from_immediate(node, offset);
245 ir_node *new_frameaddr = new_bd_sparc_Add_reg(dbgi, block, base, constant);
246 const arch_register_t *reg = arch_get_irn_register(node);
248 sched_add_before(node, new_frameaddr);
249 arch_set_irn_register(new_frameaddr, reg);
250 exchange(node, new_frameaddr);
254 static void finish_sparc_Ld(ir_node *node)
256 sparc_attr_t *attr = get_sparc_attr(node);
257 int offset = attr->immediate_value;
258 const sparc_load_store_attr_t *load_store_attr = get_sparc_load_store_attr_const(node);
260 if (! load_store_attr->is_frame_entity)
263 if (! sparc_is_value_imm_encodeable(offset)) {
264 ir_node *ptr = get_irn_n(node, n_sparc_Ld_ptr);
265 dbg_info *dbgi = get_irn_dbg_info(node);
266 ir_node *block = get_nodes_block(node);
267 ir_node *mem = get_irn_n(node, n_sparc_Ld_mem);
268 ir_mode *load_store_mode = load_store_attr->load_store_mode;
269 ir_node *constant = create_constant_from_immediate(node, offset);
270 ir_node *new_load = new_bd_sparc_Ld_reg(dbgi, block, ptr, constant, mem, load_store_mode);
271 sparc_load_store_attr_t *new_load_attr = get_sparc_load_store_attr(new_load);
272 unsigned n_outs = arch_get_irn_n_outs(node);
275 new_load_attr->is_frame_entity = load_store_attr->is_frame_entity;
276 new_load_attr->is_reg_reg = load_store_attr->is_reg_reg;
278 sched_add_before(node, new_load);
279 for (i = 0; i < n_outs; i++) {
280 arch_set_irn_register_out(new_load, i, arch_get_irn_register_out(node, i));
282 exchange(node, new_load);
287 static void finish_sparc_Ldf(ir_node *node)
289 sparc_attr_t *attr = get_sparc_attr(node);
290 int offset = attr->immediate_value;
291 const sparc_load_store_attr_t *load_store_attr = get_sparc_load_store_attr_const(node);
293 if (! load_store_attr->is_frame_entity)
296 if (! sparc_is_value_imm_encodeable(offset)) {
297 ir_node *ptr = get_irn_n(node, n_sparc_Ldf_ptr);
298 dbg_info *dbgi = get_irn_dbg_info(node);
299 ir_node *block = get_nodes_block(node);
300 ir_node *mem = get_irn_n(node, n_sparc_Ldf_mem);
301 ir_mode *load_store_mode = load_store_attr->load_store_mode;
302 ir_node *constant = create_constant_from_immediate(node, offset);
303 ir_node *new_ptr = new_bd_sparc_Add_reg(dbgi, block, ptr, constant);
304 ir_node *new_load = new_bd_sparc_Ldf_s(dbgi, block, new_ptr, mem, load_store_mode, NULL, 0, true);
305 sparc_load_store_attr_t *new_load_attr = get_sparc_load_store_attr(new_load);
306 unsigned n_outs = arch_get_irn_n_outs(node);
309 new_load_attr->is_frame_entity = load_store_attr->is_frame_entity;
310 new_load_attr->is_reg_reg = load_store_attr->is_reg_reg;
312 sched_add_before(node, new_load);
313 for (i = 0; i < n_outs; i++) {
314 arch_set_irn_register_out(new_load, i, arch_get_irn_register_out(node, i));
316 exchange(node, new_load);
321 static void finish_sparc_St(ir_node *node)
323 sparc_attr_t *attr = get_sparc_attr(node);
324 int offset = attr->immediate_value;
325 const sparc_load_store_attr_t *load_store_attr = get_sparc_load_store_attr_const(node);
327 if (! load_store_attr->is_frame_entity)
330 if (! sparc_is_value_imm_encodeable(offset)) {
331 ir_node *ptr = get_irn_n(node, n_sparc_St_ptr);
332 dbg_info *dbgi = get_irn_dbg_info(node);
333 ir_node *block = get_nodes_block(node);
334 ir_node *mem = get_irn_n(node, n_sparc_St_mem);
335 ir_node *value = get_irn_n(node, n_sparc_St_val);
336 ir_mode *load_store_mode = load_store_attr->load_store_mode;
337 ir_node *constant = create_constant_from_immediate(node, offset);
338 ir_node *new_load = new_bd_sparc_St_reg(dbgi, block, value, ptr, constant, mem, load_store_mode);
339 sparc_load_store_attr_t *new_load_attr = get_sparc_load_store_attr(new_load);
340 unsigned n_outs = arch_get_irn_n_outs(node);
343 new_load_attr->is_frame_entity = load_store_attr->is_frame_entity;
344 new_load_attr->is_reg_reg = load_store_attr->is_reg_reg;
346 sched_add_before(node, new_load);
347 for (i = 0; i < n_outs; i++) {
348 arch_set_irn_register_out(new_load, i, arch_get_irn_register_out(node, i));
350 exchange(node, new_load);
355 static void finish_sparc_Stf(ir_node *node)
357 sparc_attr_t *attr = get_sparc_attr(node);
358 int offset = attr->immediate_value;
359 const sparc_load_store_attr_t *load_store_attr = get_sparc_load_store_attr_const(node);
361 if (! load_store_attr->is_frame_entity)
364 if (! sparc_is_value_imm_encodeable(offset)) {
365 ir_node *ptr = get_irn_n(node, n_sparc_Stf_ptr);
366 dbg_info *dbgi = get_irn_dbg_info(node);
367 ir_node *block = get_nodes_block(node);
368 ir_node *mem = get_irn_n(node, n_sparc_Stf_mem);
369 ir_node *value = get_irn_n(node, n_sparc_Stf_val);
370 ir_mode *load_store_mode = load_store_attr->load_store_mode;
371 ir_node *constant = create_constant_from_immediate(node, offset);
372 ir_node *new_ptr = new_bd_sparc_Add_reg(dbgi, block, ptr, constant);
373 ir_node *new_load = new_bd_sparc_Stf_s(dbgi, block, value, new_ptr, mem, load_store_mode, NULL, 0, true);
374 sparc_load_store_attr_t *new_load_attr = get_sparc_load_store_attr(new_load);
375 unsigned n_outs = arch_get_irn_n_outs(node);
378 new_load_attr->is_frame_entity = load_store_attr->is_frame_entity;
379 new_load_attr->is_reg_reg = load_store_attr->is_reg_reg;
381 sched_add_before(node, new_load);
382 for (i = 0; i < n_outs; i++) {
383 arch_set_irn_register_out(new_load, i, arch_get_irn_register_out(node, i));
385 exchange(node, new_load);
390 static void peephole_be_IncSP(ir_node *node)
393 node = be_peephole_IncSP_IncSP(node);
394 if (!be_is_IncSP(node))
397 pred = be_get_IncSP_pred(node);
398 if (is_sparc_Save(pred) && be_has_only_one_user(pred)) {
399 int offset = -be_get_IncSP_offset(node);
400 sparc_attr_t *attr = get_sparc_attr(pred);
401 attr->immediate_value += offset;
402 be_peephole_exchange(node, pred);
406 static void peephole_sparc_FrameAddr(ir_node *node)
408 /* the peephole code currently doesn't allow this since it changes
409 * the register. Find out why and how to workaround this... */
411 const sparc_attr_t *attr = get_sparc_attr_const(node);
412 if (attr->immediate_value == 0) {
413 ir_node *base = get_irn_n(node, n_sparc_FrameAddr_base);
414 be_peephole_exchange(node, base);
420 static bool is_restorezeroopt_reg(const arch_register_t *reg)
422 unsigned index = reg->global_index;
423 return (index >= REG_G0 && index <= REG_G7)
424 || (index >= REG_I0 && index <= REG_I7);
427 static void peephole_sparc_RestoreZero(ir_node *node)
429 /* restore gives us a free "add" instruction, let's try to use that to fold
430 * an instruction in */
431 ir_node *try = sched_prev(node);
433 /* output must not be local, or out reg (it would be strange though if
435 if (be_is_Copy(try)) {
438 ir_node *new_restore;
445 const arch_register_t *reg = arch_get_irn_register(try);
446 if (!is_restorezeroopt_reg(reg))
449 op = get_irn_n(try, n_be_Copy_op);
450 fp = get_irn_n(node, n_sparc_RestoreZero_frame_pointer);
451 dbgi = get_irn_dbg_info(node);
452 block = get_nodes_block(node);
453 new_restore = new_bd_sparc_Restore_imm(dbgi, block, fp, op, NULL, 0);
454 arch_set_irn_register_out(new_restore, pn_sparc_Restore_stack,
455 &sparc_registers[REG_SP]);
456 arch_set_irn_register_out(new_restore, pn_sparc_Restore_res,
459 mode = get_irn_mode(node);
460 stack = new_r_Proj(new_restore, mode, pn_sparc_Restore_stack);
461 res = new_r_Proj(new_restore, mode, pn_sparc_Restore_res);
463 sched_add_before(node, new_restore);
464 be_peephole_exchange(node, stack);
465 be_peephole_exchange(try, res);
469 static void finish_sparc_Return(ir_node *node)
471 ir_node *schedpoint = node;
473 /* see that there is no code between Return and restore, if there is move
474 * it in front of the restore */
476 if (!sched_has_prev(schedpoint))
478 schedpoint = sched_prev(schedpoint);
479 if (is_sparc_Restore(schedpoint) || is_sparc_RestoreZero(schedpoint))
482 restore = schedpoint;
483 schedpoint = sched_prev(node);
484 /* move all code between return and restore up */
485 while (schedpoint != restore) {
486 ir_node *next_schedpoint = sched_prev(schedpoint);
487 sched_remove(schedpoint);
488 sched_add_before(restore, schedpoint);
489 schedpoint = next_schedpoint;
493 static void register_peephole_optimisation(ir_op *op, peephole_opt_func func)
495 assert(op->ops.generic == NULL);
496 op->ops.generic = (op_func) func;
499 static void sparc_collect_frame_entity_nodes(ir_node *node, void *data)
501 be_fec_env_t *env = (be_fec_env_t*)data;
505 const sparc_load_store_attr_t *attr;
507 if (be_is_Reload(node) && be_get_frame_entity(node) == NULL) {
508 mode = get_irn_mode(node);
509 align = get_mode_size_bytes(mode);
510 be_node_needs_frame_entity(env, node, mode, align);
514 if (!is_sparc_Ld(node) && !is_sparc_Ldf(node))
517 attr = get_sparc_load_store_attr_const(node);
518 entity = attr->base.immediate_value_entity;
519 mode = attr->load_store_mode;
522 if (!attr->is_frame_entity)
524 if (arch_get_irn_flags(node) & sparc_arch_irn_flag_needs_64bit_spillslot)
526 align = get_mode_size_bytes(mode);
527 be_node_needs_frame_entity(env, node, mode, align);
530 static void sparc_set_frame_entity(ir_node *node, ir_entity *entity)
532 if (is_be_node(node)) {
533 be_node_set_frame_entity(node, entity);
535 /* we only say be_node_needs_frame_entity on nodes with load_store
536 * attributes, so this should be fine */
537 sparc_load_store_attr_t *attr = get_sparc_load_store_attr(node);
538 assert(attr->is_frame_entity);
539 assert(attr->base.immediate_value_entity == NULL);
540 attr->base.immediate_value_entity = entity;
544 void sparc_finish(ir_graph *irg)
546 be_stack_layout_t *stack_layout = be_get_irg_stack_layout(irg);
547 bool at_begin = stack_layout->sp_relative ? true : false;
548 be_fec_env_t *fec_env = be_new_frame_entity_coalescer(irg);
550 irg_walk_graph(irg, NULL, sparc_collect_frame_entity_nodes, fec_env);
551 be_assign_entities(fec_env, sparc_set_frame_entity, at_begin);
552 be_free_frame_entity_coalescer(fec_env);
554 sparc_introduce_prolog_epilog(irg);
556 /* fix stack entity offsets */
557 be_abi_fix_stack_nodes(irg);
558 sparc_fix_stack_bias(irg);
560 /* perform peephole optimizations */
561 clear_irp_opcodes_generic_func();
562 register_peephole_optimisation(op_be_IncSP, peephole_be_IncSP);
563 register_peephole_optimisation(op_sparc_FrameAddr, peephole_sparc_FrameAddr);
564 register_peephole_optimisation(op_sparc_RestoreZero,
565 peephole_sparc_RestoreZero);
566 be_peephole_opt(irg);
568 /* perform legalizations (mostly fix nodes with too big immediates) */
569 clear_irp_opcodes_generic_func();
570 register_peephole_optimisation(op_be_IncSP, finish_be_IncSP);
571 register_peephole_optimisation(op_sparc_FrameAddr, finish_sparc_FrameAddr);
572 register_peephole_optimisation(op_sparc_Ld, finish_sparc_Ld);
573 register_peephole_optimisation(op_sparc_Ldf, finish_sparc_Ldf);
574 register_peephole_optimisation(op_sparc_Return, finish_sparc_Return);
575 register_peephole_optimisation(op_sparc_Save, finish_sparc_Save);
576 register_peephole_optimisation(op_sparc_St, finish_sparc_St);
577 register_peephole_optimisation(op_sparc_Stf, finish_sparc_Stf);
578 be_peephole_opt(irg);
580 be_remove_dead_nodes_from_schedule(irg);