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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"
50 #include "../bepeephole.h"
51 #include "../benode.h"
52 #include "../besched.h"
53 #include "../bespillslots.h"
54 #include "../bestack.h"
55 #include "../beirgmod.h"
57 static void kill_unused_stacknodes(ir_node *node)
59 if (get_irn_n_edges(node) > 0)
62 if (be_is_IncSP(node)) {
65 } else if (is_Phi(node)) {
66 int arity = get_irn_arity(node);
67 ir_node **ins = ALLOCAN(ir_node*, arity);
70 memcpy(ins, get_irn_in(node), arity*sizeof(ins[0]));
73 for (i = 0; i < arity; ++i)
74 kill_unused_stacknodes(ins[i]);
78 static void introduce_epilog(ir_node *ret)
80 const arch_register_t *sp_reg = &sparc_registers[REG_SP];
81 ir_graph *irg = get_irn_irg(ret);
82 be_stack_layout_t *layout = be_get_irg_stack_layout(irg);
83 ir_node *block = get_nodes_block(ret);
84 ir_type *frame_type = get_irg_frame_type(irg);
85 unsigned frame_size = get_type_size_bytes(frame_type);
86 int sp_idx = be_find_return_reg_input(ret, sp_reg);
87 ir_node *sp = get_irn_n(ret, sp_idx);
89 if (!layout->sp_relative) {
90 const arch_register_t *fp_reg = &sparc_registers[REG_FRAME_POINTER];
91 ir_node *fp = be_get_initial_reg_value(irg, fp_reg);
92 ir_node *restore = new_bd_sparc_RestoreZero(NULL, block, fp);
93 sched_add_before(ret, restore);
94 arch_set_irn_register(restore, sp_reg);
95 set_irn_n(ret, sp_idx, restore);
97 kill_unused_stacknodes(sp);
99 ir_node *incsp = be_new_IncSP(sp_reg, block, sp, -frame_size, 0);
100 set_irn_n(ret, sp_idx, incsp);
101 sched_add_before(ret, incsp);
105 void sparc_introduce_prolog_epilog(ir_graph *irg)
107 const arch_register_t *sp_reg = &sparc_registers[REG_SP];
108 ir_node *start = get_irg_start(irg);
109 be_stack_layout_t *layout = be_get_irg_stack_layout(irg);
110 ir_node *block = get_nodes_block(start);
111 ir_node *initial_sp = be_get_initial_reg_value(irg, sp_reg);
112 ir_node *sp = initial_sp;
113 ir_node *schedpoint = start;
114 ir_type *frame_type = get_irg_frame_type(irg);
115 unsigned frame_size = get_type_size_bytes(frame_type);
117 /* introduce epilog for every return node */
119 ir_node *end_block = get_irg_end_block(irg);
120 int arity = get_irn_arity(end_block);
123 for (i = 0; i < arity; ++i) {
124 ir_node *ret = get_irn_n(end_block, i);
125 assert(is_sparc_Return(ret));
126 introduce_epilog(ret);
130 while (be_is_Keep(sched_next(schedpoint)))
131 schedpoint = sched_next(schedpoint);
133 if (!layout->sp_relative) {
134 ir_node *save = new_bd_sparc_Save_imm(NULL, block, sp, NULL,
135 -SPARC_MIN_STACKSIZE-frame_size);
136 arch_set_irn_register(save, sp_reg);
137 sched_add_after(schedpoint, save);
140 edges_reroute(initial_sp, save);
141 set_irn_n(save, n_sparc_Save_stack, initial_sp);
143 /* we still need the Save even if noone is explicitely using the
144 * value. (TODO: this isn't 100% correct yet, something at the end of
145 * the function should hold the Save, even if we use a restore
146 * which just overrides it instead of using the value)
148 if (get_irn_n_edges(save) == 0) {
149 ir_node *in[] = { save };
150 ir_node *keep = be_new_Keep(block, 1, in);
151 sched_add_after(schedpoint, keep);
154 ir_node *incsp = be_new_IncSP(sp_reg, block, sp, frame_size, 0);
155 edges_reroute(initial_sp, incsp);
156 be_set_IncSP_pred(incsp, sp);
157 sched_add_after(schedpoint, incsp);
161 static void finish_sparc_Save(ir_node *node)
163 sparc_attr_t *attr = get_sparc_attr(node);
164 int offset = attr->immediate_value;
165 ir_node *schedpoint = node;
172 if (sparc_is_value_imm_encodeable(offset))
175 /* uhh only works for the imm variant yet */
176 assert(get_irn_arity(node) == 1);
178 block = get_nodes_block(node);
179 dbgi = get_irn_dbg_info(node);
180 stack = get_irn_n(node, n_sparc_Save_stack);
181 entity = attr->immediate_value_entity;
182 new_save = new_bd_sparc_Save_imm(dbgi, block, stack, entity, 0);
183 arch_set_irn_register(new_save, &sparc_registers[REG_SP]);
186 sched_add_after(node, new_save);
187 schedpoint = new_save;
188 while (offset > SPARC_IMMEDIATE_MAX || offset < SPARC_IMMEDIATE_MIN) {
190 stack = be_new_IncSP(&sparc_registers[REG_SP], block, stack,
191 SPARC_IMMEDIATE_MIN, 0);
192 offset -= -SPARC_IMMEDIATE_MIN;
194 stack = be_new_IncSP(&sparc_registers[REG_SP], block, stack,
195 -SPARC_IMMEDIATE_MIN, 0);
196 offset -= SPARC_IMMEDIATE_MIN;
198 sched_add_after(schedpoint, stack);
201 attr = get_sparc_attr(new_save);
202 attr->immediate_value = offset;
203 be_peephole_exchange(node, stack);
207 * sparc immediates are limited. Split IncSP with bigger immediates if
210 static void finish_be_IncSP(ir_node *node)
213 int offset = be_get_IncSP_offset(node);
214 ir_node *sp = be_get_IncSP_pred(node);
217 /* we might have to break the IncSP apart if the constant has become too
224 if (sparc_is_value_imm_encodeable(-offset))
227 /* split incsp into multiple instructions */
228 block = get_nodes_block(node);
229 while (offset > -SPARC_IMMEDIATE_MIN) {
230 sp = be_new_IncSP(&sparc_registers[REG_SP], block, sp,
231 sign * -SPARC_IMMEDIATE_MIN, 0);
232 sched_add_before(node, sp);
233 offset -= -SPARC_IMMEDIATE_MIN;
236 be_set_IncSP_pred(node, sp);
237 be_set_IncSP_offset(node, sign*offset);
241 * adjust sp-relative offsets. Split into multiple instructions if offset
242 * exceeds sparc immediate range.
244 static void finish_sparc_FrameAddr(ir_node *node)
246 /* adapt to sparc stack magic */
247 sparc_attr_t *attr = get_sparc_attr(node);
248 int offset = attr->immediate_value;
249 ir_node *base = get_irn_n(node, n_sparc_FrameAddr_base);
250 dbg_info *dbgi = get_irn_dbg_info(node);
251 ir_node *block = get_nodes_block(node);
259 if (offset > -SPARC_IMMEDIATE_MIN) {
260 ir_entity *entity = attr->immediate_value_entity;
261 ir_node *new_frameaddr
262 = new_bd_sparc_FrameAddr(dbgi, block, base, entity, 0);
263 ir_node *schedpoint = node;
264 const arch_register_t *reg = arch_get_irn_register(node);
266 sched_add_after(schedpoint, new_frameaddr);
267 schedpoint = new_frameaddr;
268 arch_set_irn_register(new_frameaddr, reg);
269 base = new_frameaddr;
271 while (offset > -SPARC_IMMEDIATE_MIN) {
273 base = new_bd_sparc_Sub_imm(dbgi, block, base, NULL,
274 SPARC_IMMEDIATE_MIN);
276 base = new_bd_sparc_Add_imm(dbgi, block, base, NULL,
277 SPARC_IMMEDIATE_MIN);
279 arch_set_irn_register(base, reg);
280 sched_add_after(schedpoint, base);
283 offset -= -SPARC_IMMEDIATE_MIN;
286 be_peephole_exchange(node, base);
287 attr = get_sparc_attr(new_frameaddr);
289 attr->immediate_value = sign*offset;
292 static void peephole_be_IncSP(ir_node *node)
295 node = be_peephole_IncSP_IncSP(node);
296 if (!be_is_IncSP(node))
299 pred = be_get_IncSP_pred(node);
300 if (is_sparc_Save(pred) && be_has_only_one_user(pred)) {
301 int offset = -be_get_IncSP_offset(node);
302 sparc_attr_t *attr = get_sparc_attr(pred);
303 attr->immediate_value += offset;
304 be_peephole_exchange(node, pred);
308 static void peephole_sparc_FrameAddr(ir_node *node)
310 /* the peephole code currently doesn't allow this since it changes
311 * the register. Find out why and how to workaround this... */
313 const sparc_attr_t *attr = get_sparc_attr_const(node);
314 if (attr->immediate_value == 0) {
315 ir_node *base = get_irn_n(node, n_sparc_FrameAddr_base);
316 be_peephole_exchange(node, base);
322 static void finish_sparc_Return(ir_node *node)
324 ir_node *schedpoint = node;
326 /* see that there is no code between Return and restore, if there is move
327 * it in front of the restore */
329 if (!sched_has_prev(schedpoint))
331 schedpoint = sched_prev(schedpoint);
332 if (is_sparc_Restore(schedpoint) || is_sparc_RestoreZero(schedpoint))
335 restore = schedpoint;
336 schedpoint = sched_prev(node);
337 /* move all code between return and restore up */
338 while (schedpoint != restore) {
339 ir_node *next_schedpoint = sched_prev(schedpoint);
340 sched_remove(schedpoint);
341 sched_add_before(restore, schedpoint);
342 schedpoint = next_schedpoint;
346 static void register_peephole_optimisation(ir_op *op, peephole_opt_func func)
348 assert(op->ops.generic == NULL);
349 op->ops.generic = (op_func) func;
353 * transform reload node => load
355 static void transform_Reload(ir_node *node)
357 ir_node *block = get_nodes_block(node);
358 dbg_info *dbgi = get_irn_dbg_info(node);
359 ir_node *ptr = get_irn_n(node, n_be_Spill_frame);
360 ir_node *mem = get_irn_n(node, n_be_Reload_mem);
361 ir_mode *mode = get_irn_mode(node);
362 ir_entity *entity = be_get_frame_entity(node);
363 const arch_register_t *reg;
367 ir_node *sched_point = sched_prev(node);
369 load = new_bd_sparc_Ld_imm(dbgi, block, ptr, mem, mode, entity, 0, true);
370 sched_add_after(sched_point, load);
373 proj = new_rd_Proj(dbgi, load, mode, pn_sparc_Ld_res);
375 reg = arch_get_irn_register(node);
376 arch_set_irn_register(proj, reg);
378 exchange(node, proj);
382 * transform spill node => store
384 static void transform_Spill(ir_node *node)
386 ir_node *block = get_nodes_block(node);
387 dbg_info *dbgi = get_irn_dbg_info(node);
388 ir_node *ptr = get_irn_n(node, n_be_Spill_frame);
389 ir_graph *irg = get_irn_irg(node);
390 ir_node *mem = get_irg_no_mem(irg);
391 ir_node *val = get_irn_n(node, n_be_Spill_val);
392 ir_mode *mode = get_irn_mode(val);
393 ir_entity *entity = be_get_frame_entity(node);
394 ir_node *sched_point;
397 sched_point = sched_prev(node);
398 store = new_bd_sparc_St_imm(dbgi, block, val, ptr, mem, mode, entity, 0, true);
400 sched_add_after(sched_point, store);
402 exchange(node, store);
406 * walker to transform be_Spill and be_Reload nodes
408 static void sparc_after_ra_walker(ir_node *block, void *data)
410 ir_node *node, *prev;
413 for (node = sched_last(block); !sched_is_begin(node); node = prev) {
414 prev = sched_prev(node);
416 if (be_is_Reload(node)) {
417 transform_Reload(node);
418 } else if (be_is_Spill(node)) {
419 transform_Spill(node);
424 static void sparc_collect_frame_entity_nodes(ir_node *node, void *data)
426 be_fec_env_t *env = (be_fec_env_t*)data;
430 const sparc_load_store_attr_t *attr;
432 if (be_is_Reload(node) && be_get_frame_entity(node) == NULL) {
433 mode = get_irn_mode(node);
434 align = get_mode_size_bytes(mode);
435 be_node_needs_frame_entity(env, node, mode, align);
439 if (!is_sparc_Ld(node) && !is_sparc_Ldf(node))
442 attr = get_sparc_load_store_attr_const(node);
443 entity = attr->base.immediate_value_entity;
444 mode = attr->load_store_mode;
447 if (!attr->is_frame_entity)
449 if (arch_irn_get_flags(node) & sparc_arch_irn_flag_needs_64bit_spillslot)
451 align = get_mode_size_bytes(mode);
452 be_node_needs_frame_entity(env, node, mode, align);
455 static void sparc_set_frame_entity(ir_node *node, ir_entity *entity)
457 if (is_be_node(node)) {
458 be_node_set_frame_entity(node, entity);
460 /* we only say be_node_needs_frame_entity on nodes with load_store
461 * attributes, so this should be fine */
462 sparc_load_store_attr_t *attr = get_sparc_load_store_attr(node);
463 assert(attr->is_frame_entity);
464 assert(attr->base.immediate_value_entity == NULL);
465 attr->base.immediate_value_entity = entity;
469 void sparc_finish(ir_graph *irg)
471 be_stack_layout_t *stack_layout = be_get_irg_stack_layout(irg);
472 bool at_begin = stack_layout->sp_relative ? true : false;
473 be_fec_env_t *fec_env = be_new_frame_entity_coalescer(irg);
475 irg_walk_graph(irg, NULL, sparc_collect_frame_entity_nodes, fec_env);
476 be_assign_entities(fec_env, sparc_set_frame_entity, at_begin);
477 be_free_frame_entity_coalescer(fec_env);
479 irg_block_walk_graph(irg, NULL, sparc_after_ra_walker, NULL);
481 sparc_introduce_prolog_epilog(irg);
483 /* fix stack entity offsets */
484 be_abi_fix_stack_nodes(irg);
485 sparc_fix_stack_bias(irg);
487 /* perform peephole optimizations */
488 clear_irp_opcodes_generic_func();
489 register_peephole_optimisation(op_be_IncSP, peephole_be_IncSP);
490 register_peephole_optimisation(op_sparc_FrameAddr, peephole_sparc_FrameAddr);
491 be_peephole_opt(irg);
493 /* perform legalizations (mostly fix nodes with too big immediates) */
494 clear_irp_opcodes_generic_func();
495 register_peephole_optimisation(op_be_IncSP, finish_be_IncSP);
496 register_peephole_optimisation(op_sparc_FrameAddr, finish_sparc_FrameAddr);
497 register_peephole_optimisation(op_sparc_Return, finish_sparc_Return);
498 register_peephole_optimisation(op_sparc_Save, finish_sparc_Save);
499 be_peephole_opt(irg);
501 be_remove_dead_nodes_from_schedule(irg);