1 /*
2 * Copyright (c) 1998, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "asm/assembler.inline.hpp"
27 #include "asm/macroAssembler.inline.hpp"
28 #include "code/compiledIC.hpp"
29 #include "code/debugInfo.hpp"
30 #include "code/debugInfoRec.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "compiler/compilerDirectives.hpp"
33 #include "compiler/oopMap.hpp"
34 #include "memory/allocation.inline.hpp"
35 #include "opto/ad.hpp"
36 #include "opto/callnode.hpp"
37 #include "opto/cfgnode.hpp"
38 #include "opto/locknode.hpp"
39 #include "opto/machnode.hpp"
40 #include "opto/optoreg.hpp"
41 #include "opto/output.hpp"
42 #include "opto/regalloc.hpp"
43 #include "opto/runtime.hpp"
44 #include "opto/subnode.hpp"
45 #include "opto/type.hpp"
46 #include "runtime/handles.inline.hpp"
47 #include "utilities/xmlstream.hpp"
48
49 #ifndef PRODUCT
50 #define DEBUG_ARG(x) , x
51 #else
52 #define DEBUG_ARG(x)
53 #endif
54
55 // Convert Nodes to instruction bits and pass off to the VM
56 void Compile::Output() {
57 // RootNode goes
58 assert( _cfg->get_root_block()->number_of_nodes() == 0, "" );
59
60 // The number of new nodes (mostly MachNop) is proportional to
61 // the number of java calls and inner loops which are aligned.
62 if ( C->check_node_count((NodeLimitFudgeFactor + C->java_calls()*3 +
63 C->inner_loops()*(OptoLoopAlignment-1)),
64 "out of nodes before code generation" ) ) {
65 return;
66 }
67 // Make sure I can find the Start Node
68 Block *entry = _cfg->get_block(1);
69 Block *broot = _cfg->get_root_block();
70
71 const StartNode *start = entry->head()->as_Start();
72
73 // Replace StartNode with prolog
74 MachPrologNode *prolog = new MachPrologNode();
75 entry->map_node(prolog, 0);
76 _cfg->map_node_to_block(prolog, entry);
77 _cfg->unmap_node_from_block(start); // start is no longer in any block
78
79 // Virtual methods need an unverified entry point
80 if (is_osr_compilation()) {
81 if (PoisonOSREntry) {
82 // TODO: Should use a ShouldNotReachHereNode...
83 _cfg->insert( broot, 0, new MachBreakpointNode() );
84 }
85 } else {
86 if (_method && !_method->flags().is_static()) {
87 // Insert unvalidated entry point
88 _cfg->insert(broot, 0, new MachUEPNode());
89 }
90 }
91
92 // Break before main entry point
93 if ((_method && C->directive()->BreakAtExecuteOption) ||
94 (OptoBreakpoint && is_method_compilation()) ||
95 (OptoBreakpointOSR && is_osr_compilation()) ||
96 (OptoBreakpointC2R && !_method) ) {
97 // checking for _method means that OptoBreakpoint does not apply to
98 // runtime stubs or frame converters
99 _cfg->insert( entry, 1, new MachBreakpointNode() );
100 }
101
102 // Insert epilogs before every return
103 for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
104 Block* block = _cfg->get_block(i);
105 if (!block->is_connector() && block->non_connector_successor(0) == _cfg->get_root_block()) { // Found a program exit point?
106 Node* m = block->end();
107 if (m->is_Mach() && m->as_Mach()->ideal_Opcode() != Op_Halt) {
108 MachEpilogNode* epilog = new MachEpilogNode(m->as_Mach()->ideal_Opcode() == Op_Return);
109 block->add_inst(epilog);
110 _cfg->map_node_to_block(epilog, block);
111 }
112 }
113 }
114
115 uint* blk_starts = NEW_RESOURCE_ARRAY(uint, _cfg->number_of_blocks() + 1);
116 blk_starts[0] = 0;
117
118 // Initialize code buffer and process short branches.
119 CodeBuffer* cb = init_buffer(blk_starts);
120
121 if (cb == NULL || failing()) {
122 return;
123 }
124
125 ScheduleAndBundle();
126
127 #ifndef PRODUCT
128 if (trace_opto_output()) {
129 tty->print("\n---- After ScheduleAndBundle ----\n");
130 for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
131 tty->print("\nBB#%03d:\n", i);
132 Block* block = _cfg->get_block(i);
133 for (uint j = 0; j < block->number_of_nodes(); j++) {
134 Node* n = block->get_node(j);
135 OptoReg::Name reg = _regalloc->get_reg_first(n);
136 tty->print(" %-6s ", reg >= 0 && reg < REG_COUNT ? Matcher::regName[reg] : "");
137 n->dump();
138 }
139 }
140 }
141 #endif
142
143 if (failing()) {
144 return;
145 }
146
147 BuildOopMaps();
148
149 if (failing()) {
150 return;
151 }
152
153 fill_buffer(cb, blk_starts);
154 }
155
156 bool Compile::need_stack_bang(int frame_size_in_bytes) const {
157 // Determine if we need to generate a stack overflow check.
158 // Do it if the method is not a stub function and
159 // has java calls or has frame size > vm_page_size/8.
160 // The debug VM checks that deoptimization doesn't trigger an
161 // unexpected stack overflow (compiled method stack banging should
162 // guarantee it doesn't happen) so we always need the stack bang in
163 // a debug VM.
164 return (UseStackBanging && stub_function() == NULL &&
165 (has_java_calls() || frame_size_in_bytes > os::vm_page_size()>>3
166 DEBUG_ONLY(|| true)));
167 }
168
169 bool Compile::need_register_stack_bang() const {
170 // Determine if we need to generate a register stack overflow check.
171 // This is only used on architectures which have split register
172 // and memory stacks (ie. IA64).
173 // Bang if the method is not a stub function and has java calls
174 return (stub_function() == NULL && has_java_calls());
175 }
176
177
178 // Compute the size of first NumberOfLoopInstrToAlign instructions at the top
179 // of a loop. When aligning a loop we need to provide enough instructions
180 // in cpu's fetch buffer to feed decoders. The loop alignment could be
181 // avoided if we have enough instructions in fetch buffer at the head of a loop.
182 // By default, the size is set to 999999 by Block's constructor so that
183 // a loop will be aligned if the size is not reset here.
184 //
185 // Note: Mach instructions could contain several HW instructions
186 // so the size is estimated only.
187 //
188 void Compile::compute_loop_first_inst_sizes() {
189 // The next condition is used to gate the loop alignment optimization.
190 // Don't aligned a loop if there are enough instructions at the head of a loop
191 // or alignment padding is larger then MaxLoopPad. By default, MaxLoopPad
192 // is equal to OptoLoopAlignment-1 except on new Intel cpus, where it is
193 // equal to 11 bytes which is the largest address NOP instruction.
194 if (MaxLoopPad < OptoLoopAlignment - 1) {
195 uint last_block = _cfg->number_of_blocks() - 1;
196 for (uint i = 1; i <= last_block; i++) {
197 Block* block = _cfg->get_block(i);
198 // Check the first loop's block which requires an alignment.
199 if (block->loop_alignment() > (uint)relocInfo::addr_unit()) {
200 uint sum_size = 0;
201 uint inst_cnt = NumberOfLoopInstrToAlign;
202 inst_cnt = block->compute_first_inst_size(sum_size, inst_cnt, _regalloc);
203
204 // Check subsequent fallthrough blocks if the loop's first
205 // block(s) does not have enough instructions.
206 Block *nb = block;
207 while(inst_cnt > 0 &&
208 i < last_block &&
209 !_cfg->get_block(i + 1)->has_loop_alignment() &&
210 !nb->has_successor(block)) {
211 i++;
212 nb = _cfg->get_block(i);
213 inst_cnt = nb->compute_first_inst_size(sum_size, inst_cnt, _regalloc);
214 } // while( inst_cnt > 0 && i < last_block )
215
216 block->set_first_inst_size(sum_size);
217 } // f( b->head()->is_Loop() )
218 } // for( i <= last_block )
219 } // if( MaxLoopPad < OptoLoopAlignment-1 )
220 }
221
222 // The architecture description provides short branch variants for some long
223 // branch instructions. Replace eligible long branches with short branches.
224 void Compile::shorten_branches(uint* blk_starts, int& code_size, int& reloc_size, int& stub_size) {
225 // Compute size of each block, method size, and relocation information size
226 uint nblocks = _cfg->number_of_blocks();
227
228 uint* jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
229 uint* jmp_size = NEW_RESOURCE_ARRAY(uint,nblocks);
230 int* jmp_nidx = NEW_RESOURCE_ARRAY(int ,nblocks);
231
232 // Collect worst case block paddings
233 int* block_worst_case_pad = NEW_RESOURCE_ARRAY(int, nblocks);
234 memset(block_worst_case_pad, 0, nblocks * sizeof(int));
235
236 DEBUG_ONLY( uint *jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks); )
237 DEBUG_ONLY( uint *jmp_rule = NEW_RESOURCE_ARRAY(uint,nblocks); )
238
239 bool has_short_branch_candidate = false;
240
241 // Initialize the sizes to 0
242 code_size = 0; // Size in bytes of generated code
243 stub_size = 0; // Size in bytes of all stub entries
244 // Size in bytes of all relocation entries, including those in local stubs.
245 // Start with 2-bytes of reloc info for the unvalidated entry point
246 reloc_size = 1; // Number of relocation entries
247
248 // Make three passes. The first computes pessimistic blk_starts,
249 // relative jmp_offset and reloc_size information. The second performs
250 // short branch substitution using the pessimistic sizing. The
251 // third inserts nops where needed.
252
253 // Step one, perform a pessimistic sizing pass.
254 uint last_call_adr = max_juint;
255 uint last_avoid_back_to_back_adr = max_juint;
256 uint nop_size = (new MachNopNode())->size(_regalloc);
257 for (uint i = 0; i < nblocks; i++) { // For all blocks
258 Block* block = _cfg->get_block(i);
259
260 // During short branch replacement, we store the relative (to blk_starts)
261 // offset of jump in jmp_offset, rather than the absolute offset of jump.
262 // This is so that we do not need to recompute sizes of all nodes when
263 // we compute correct blk_starts in our next sizing pass.
264 jmp_offset[i] = 0;
265 jmp_size[i] = 0;
266 jmp_nidx[i] = -1;
267 DEBUG_ONLY( jmp_target[i] = 0; )
268 DEBUG_ONLY( jmp_rule[i] = 0; )
269
270 // Sum all instruction sizes to compute block size
271 uint last_inst = block->number_of_nodes();
272 uint blk_size = 0;
273 for (uint j = 0; j < last_inst; j++) {
274 Node* nj = block->get_node(j);
275 // Handle machine instruction nodes
276 if (nj->is_Mach()) {
277 MachNode *mach = nj->as_Mach();
278 blk_size += (mach->alignment_required() - 1) * relocInfo::addr_unit(); // assume worst case padding
279 reloc_size += mach->reloc();
280 if (mach->is_MachCall()) {
281 // add size information for trampoline stub
282 // class CallStubImpl is platform-specific and defined in the *.ad files.
283 stub_size += CallStubImpl::size_call_trampoline();
284 reloc_size += CallStubImpl::reloc_call_trampoline();
285
286 MachCallNode *mcall = mach->as_MachCall();
287 // This destination address is NOT PC-relative
288
289 if (mcall->entry_point() != NULL) {
290 mcall->method_set((intptr_t)mcall->entry_point());
291 }
292
293 if (mcall->is_MachCallJava() && mcall->as_MachCallJava()->_method) {
294 stub_size += CompiledStaticCall::to_interp_stub_size();
295 reloc_size += CompiledStaticCall::reloc_to_interp_stub();
296 #if INCLUDE_AOT
297 stub_size += CompiledStaticCall::to_aot_stub_size();
298 reloc_size += CompiledStaticCall::reloc_to_aot_stub();
299 #endif
300 }
301 } else if (mach->is_MachSafePoint()) {
302 // If call/safepoint are adjacent, account for possible
303 // nop to disambiguate the two safepoints.
304 // ScheduleAndBundle() can rearrange nodes in a block,
305 // check for all offsets inside this block.
306 if (last_call_adr >= blk_starts[i]) {
307 blk_size += nop_size;
308 }
309 }
310 if (mach->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
311 // Nop is inserted between "avoid back to back" instructions.
312 // ScheduleAndBundle() can rearrange nodes in a block,
313 // check for all offsets inside this block.
314 if (last_avoid_back_to_back_adr >= blk_starts[i]) {
315 blk_size += nop_size;
316 }
317 }
318 if (mach->may_be_short_branch()) {
319 if (!nj->is_MachBranch()) {
320 #ifndef PRODUCT
321 nj->dump(3);
322 #endif
323 Unimplemented();
324 }
325 assert(jmp_nidx[i] == -1, "block should have only one branch");
326 jmp_offset[i] = blk_size;
327 jmp_size[i] = nj->size(_regalloc);
328 jmp_nidx[i] = j;
329 has_short_branch_candidate = true;
330 }
331 }
332 blk_size += nj->size(_regalloc);
333 // Remember end of call offset
334 if (nj->is_MachCall() && !nj->is_MachCallLeaf()) {
335 last_call_adr = blk_starts[i]+blk_size;
336 }
337 // Remember end of avoid_back_to_back offset
338 if (nj->is_Mach() && nj->as_Mach()->avoid_back_to_back(MachNode::AVOID_AFTER)) {
339 last_avoid_back_to_back_adr = blk_starts[i]+blk_size;
340 }
341 }
342
343 // When the next block starts a loop, we may insert pad NOP
344 // instructions. Since we cannot know our future alignment,
345 // assume the worst.
346 if (i < nblocks - 1) {
347 Block* nb = _cfg->get_block(i + 1);
348 int max_loop_pad = nb->code_alignment()-relocInfo::addr_unit();
349 if (max_loop_pad > 0) {
350 assert(is_power_of_2(max_loop_pad+relocInfo::addr_unit()), "");
351 // Adjust last_call_adr and/or last_avoid_back_to_back_adr.
352 // If either is the last instruction in this block, bump by
353 // max_loop_pad in lock-step with blk_size, so sizing
354 // calculations in subsequent blocks still can conservatively
355 // detect that it may the last instruction in this block.
356 if (last_call_adr == blk_starts[i]+blk_size) {
357 last_call_adr += max_loop_pad;
358 }
359 if (last_avoid_back_to_back_adr == blk_starts[i]+blk_size) {
360 last_avoid_back_to_back_adr += max_loop_pad;
361 }
362 blk_size += max_loop_pad;
363 block_worst_case_pad[i + 1] = max_loop_pad;
364 }
365 }
366
367 // Save block size; update total method size
368 blk_starts[i+1] = blk_starts[i]+blk_size;
369 }
370
371 // Step two, replace eligible long jumps.
372 bool progress = true;
373 uint last_may_be_short_branch_adr = max_juint;
374 while (has_short_branch_candidate && progress) {
375 progress = false;
376 has_short_branch_candidate = false;
377 int adjust_block_start = 0;
378 for (uint i = 0; i < nblocks; i++) {
379 Block* block = _cfg->get_block(i);
380 int idx = jmp_nidx[i];
381 MachNode* mach = (idx == -1) ? NULL: block->get_node(idx)->as_Mach();
382 if (mach != NULL && mach->may_be_short_branch()) {
383 #ifdef ASSERT
384 assert(jmp_size[i] > 0 && mach->is_MachBranch(), "sanity");
385 int j;
386 // Find the branch; ignore trailing NOPs.
387 for (j = block->number_of_nodes()-1; j>=0; j--) {
388 Node* n = block->get_node(j);
389 if (!n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con)
390 break;
391 }
392 assert(j >= 0 && j == idx && block->get_node(j) == (Node*)mach, "sanity");
393 #endif
394 int br_size = jmp_size[i];
395 int br_offs = blk_starts[i] + jmp_offset[i];
396
397 // This requires the TRUE branch target be in succs[0]
398 uint bnum = block->non_connector_successor(0)->_pre_order;
399 int offset = blk_starts[bnum] - br_offs;
400 if (bnum > i) { // adjust following block's offset
401 offset -= adjust_block_start;
402 }
403
404 // This block can be a loop header, account for the padding
405 // in the previous block.
406 int block_padding = block_worst_case_pad[i];
407 assert(i == 0 || block_padding == 0 || br_offs >= block_padding, "Should have at least a padding on top");
408 // In the following code a nop could be inserted before
409 // the branch which will increase the backward distance.
410 bool needs_padding = ((uint)(br_offs - block_padding) == last_may_be_short_branch_adr);
411 assert(!needs_padding || jmp_offset[i] == 0, "padding only branches at the beginning of block");
412
413 if (needs_padding && offset <= 0)
414 offset -= nop_size;
415
416 if (_matcher->is_short_branch_offset(mach->rule(), br_size, offset)) {
417 // We've got a winner. Replace this branch.
418 MachNode* replacement = mach->as_MachBranch()->short_branch_version();
419
420 // Update the jmp_size.
421 int new_size = replacement->size(_regalloc);
422 int diff = br_size - new_size;
423 assert(diff >= (int)nop_size, "short_branch size should be smaller");
424 // Conservatively take into account padding between
425 // avoid_back_to_back branches. Previous branch could be
426 // converted into avoid_back_to_back branch during next
427 // rounds.
428 if (needs_padding && replacement->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
429 jmp_offset[i] += nop_size;
430 diff -= nop_size;
431 }
432 adjust_block_start += diff;
433 block->map_node(replacement, idx);
434 mach->subsume_by(replacement, C);
435 mach = replacement;
436 progress = true;
437
438 jmp_size[i] = new_size;
439 DEBUG_ONLY( jmp_target[i] = bnum; );
440 DEBUG_ONLY( jmp_rule[i] = mach->rule(); );
441 } else {
442 // The jump distance is not short, try again during next iteration.
443 has_short_branch_candidate = true;
444 }
445 } // (mach->may_be_short_branch())
446 if (mach != NULL && (mach->may_be_short_branch() ||
447 mach->avoid_back_to_back(MachNode::AVOID_AFTER))) {
448 last_may_be_short_branch_adr = blk_starts[i] + jmp_offset[i] + jmp_size[i];
449 }
450 blk_starts[i+1] -= adjust_block_start;
451 }
452 }
453
454 #ifdef ASSERT
455 for (uint i = 0; i < nblocks; i++) { // For all blocks
456 if (jmp_target[i] != 0) {
457 int br_size = jmp_size[i];
458 int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
459 if (!_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
460 tty->print_cr("target (%d) - jmp_offset(%d) = offset (%d), jump_size(%d), jmp_block B%d, target_block B%d", blk_starts[jmp_target[i]], blk_starts[i] + jmp_offset[i], offset, br_size, i, jmp_target[i]);
461 }
462 assert(_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset), "Displacement too large for short jmp");
463 }
464 }
465 #endif
466
467 // Step 3, compute the offsets of all blocks, will be done in fill_buffer()
468 // after ScheduleAndBundle().
469
470 // ------------------
471 // Compute size for code buffer
472 code_size = blk_starts[nblocks];
473
474 // Relocation records
475 reloc_size += 1; // Relo entry for exception handler
476
477 // Adjust reloc_size to number of record of relocation info
478 // Min is 2 bytes, max is probably 6 or 8, with a tax up to 25% for
479 // a relocation index.
480 // The CodeBuffer will expand the locs array if this estimate is too low.
481 reloc_size *= 10 / sizeof(relocInfo);
482 }
483
484 //------------------------------FillLocArray-----------------------------------
485 // Create a bit of debug info and append it to the array. The mapping is from
486 // Java local or expression stack to constant, register or stack-slot. For
487 // doubles, insert 2 mappings and return 1 (to tell the caller that the next
488 // entry has been taken care of and caller should skip it).
489 static LocationValue *new_loc_value( PhaseRegAlloc *ra, OptoReg::Name regnum, Location::Type l_type ) {
490 // This should never have accepted Bad before
491 assert(OptoReg::is_valid(regnum), "location must be valid");
492 return (OptoReg::is_reg(regnum))
493 ? new LocationValue(Location::new_reg_loc(l_type, OptoReg::as_VMReg(regnum)) )
494 : new LocationValue(Location::new_stk_loc(l_type, ra->reg2offset(regnum)));
495 }
496
497
498 ObjectValue*
499 Compile::sv_for_node_id(GrowableArray<ScopeValue*> *objs, int id) {
500 for (int i = 0; i < objs->length(); i++) {
501 assert(objs->at(i)->is_object(), "corrupt object cache");
502 ObjectValue* sv = (ObjectValue*) objs->at(i);
503 if (sv->id() == id) {
504 return sv;
505 }
506 }
507 // Otherwise..
508 return NULL;
509 }
510
511 void Compile::set_sv_for_object_node(GrowableArray<ScopeValue*> *objs,
512 ObjectValue* sv ) {
513 assert(sv_for_node_id(objs, sv->id()) == NULL, "Precondition");
514 objs->append(sv);
515 }
516
517
518 void Compile::FillLocArray( int idx, MachSafePointNode* sfpt, Node *local,
519 GrowableArray<ScopeValue*> *array,
520 GrowableArray<ScopeValue*> *objs ) {
521 assert( local, "use _top instead of null" );
522 if (array->length() != idx) {
523 assert(array->length() == idx + 1, "Unexpected array count");
524 // Old functionality:
525 // return
526 // New functionality:
527 // Assert if the local is not top. In product mode let the new node
528 // override the old entry.
529 assert(local == top(), "LocArray collision");
530 if (local == top()) {
531 return;
532 }
533 array->pop();
534 }
535 const Type *t = local->bottom_type();
536
537 // Is it a safepoint scalar object node?
538 if (local->is_SafePointScalarObject()) {
539 SafePointScalarObjectNode* spobj = local->as_SafePointScalarObject();
540
541 ObjectValue* sv = Compile::sv_for_node_id(objs, spobj->_idx);
542 if (sv == NULL) {
543 ciKlass* cik = t->is_oopptr()->klass();
544 assert(cik->is_instance_klass() ||
545 cik->is_array_klass(), "Not supported allocation.");
546 sv = new ObjectValue(spobj->_idx,
547 new ConstantOopWriteValue(cik->java_mirror()->constant_encoding()));
548 Compile::set_sv_for_object_node(objs, sv);
549
550 uint first_ind = spobj->first_index(sfpt->jvms());
551 for (uint i = 0; i < spobj->n_fields(); i++) {
552 Node* fld_node = sfpt->in(first_ind+i);
553 (void)FillLocArray(sv->field_values()->length(), sfpt, fld_node, sv->field_values(), objs);
554 }
555 }
556 array->append(sv);
557 return;
558 }
559
560 // Grab the register number for the local
561 OptoReg::Name regnum = _regalloc->get_reg_first(local);
562 if( OptoReg::is_valid(regnum) ) {// Got a register/stack?
563 // Record the double as two float registers.
564 // The register mask for such a value always specifies two adjacent
565 // float registers, with the lower register number even.
566 // Normally, the allocation of high and low words to these registers
567 // is irrelevant, because nearly all operations on register pairs
568 // (e.g., StoreD) treat them as a single unit.
569 // Here, we assume in addition that the words in these two registers
570 // stored "naturally" (by operations like StoreD and double stores
571 // within the interpreter) such that the lower-numbered register
572 // is written to the lower memory address. This may seem like
573 // a machine dependency, but it is not--it is a requirement on
574 // the author of the <arch>.ad file to ensure that, for every
575 // even/odd double-register pair to which a double may be allocated,
576 // the word in the even single-register is stored to the first
577 // memory word. (Note that register numbers are completely
578 // arbitrary, and are not tied to any machine-level encodings.)
579 #ifdef _LP64
580 if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon ) {
581 array->append(new ConstantIntValue((jint)0));
582 array->append(new_loc_value( _regalloc, regnum, Location::dbl ));
583 } else if ( t->base() == Type::Long ) {
584 array->append(new ConstantIntValue((jint)0));
585 array->append(new_loc_value( _regalloc, regnum, Location::lng ));
586 } else if ( t->base() == Type::RawPtr ) {
587 // jsr/ret return address which must be restored into a the full
588 // width 64-bit stack slot.
589 array->append(new_loc_value( _regalloc, regnum, Location::lng ));
590 }
591 #else //_LP64
592 #ifdef SPARC
593 if (t->base() == Type::Long && OptoReg::is_reg(regnum)) {
594 // For SPARC we have to swap high and low words for
595 // long values stored in a single-register (g0-g7).
596 array->append(new_loc_value( _regalloc, regnum , Location::normal ));
597 array->append(new_loc_value( _regalloc, OptoReg::add(regnum,1), Location::normal ));
598 } else
599 #endif //SPARC
600 if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon || t->base() == Type::Long ) {
601 // Repack the double/long as two jints.
602 // The convention the interpreter uses is that the second local
603 // holds the first raw word of the native double representation.
604 // This is actually reasonable, since locals and stack arrays
605 // grow downwards in all implementations.
606 // (If, on some machine, the interpreter's Java locals or stack
607 // were to grow upwards, the embedded doubles would be word-swapped.)
608 array->append(new_loc_value( _regalloc, OptoReg::add(regnum,1), Location::normal ));
609 array->append(new_loc_value( _regalloc, regnum , Location::normal ));
610 }
611 #endif //_LP64
612 else if( (t->base() == Type::FloatBot || t->base() == Type::FloatCon) &&
613 OptoReg::is_reg(regnum) ) {
614 array->append(new_loc_value( _regalloc, regnum, Matcher::float_in_double()
615 ? Location::float_in_dbl : Location::normal ));
616 } else if( t->base() == Type::Int && OptoReg::is_reg(regnum) ) {
617 array->append(new_loc_value( _regalloc, regnum, Matcher::int_in_long
618 ? Location::int_in_long : Location::normal ));
619 } else if( t->base() == Type::NarrowOop ) {
620 array->append(new_loc_value( _regalloc, regnum, Location::narrowoop ));
621 } else {
622 array->append(new_loc_value( _regalloc, regnum, _regalloc->is_oop(local) ? Location::oop : Location::normal ));
623 }
624 return;
625 }
626
627 // No register. It must be constant data.
628 switch (t->base()) {
629 case Type::Half: // Second half of a double
630 ShouldNotReachHere(); // Caller should skip 2nd halves
631 break;
632 case Type::AnyPtr:
633 array->append(new ConstantOopWriteValue(NULL));
634 break;
635 case Type::AryPtr:
636 case Type::InstPtr: // fall through
637 array->append(new ConstantOopWriteValue(t->isa_oopptr()->const_oop()->constant_encoding()));
638 break;
639 case Type::NarrowOop:
640 if (t == TypeNarrowOop::NULL_PTR) {
641 array->append(new ConstantOopWriteValue(NULL));
642 } else {
643 array->append(new ConstantOopWriteValue(t->make_ptr()->isa_oopptr()->const_oop()->constant_encoding()));
644 }
645 break;
646 case Type::Int:
647 array->append(new ConstantIntValue(t->is_int()->get_con()));
648 break;
649 case Type::RawPtr:
650 // A return address (T_ADDRESS).
651 assert((intptr_t)t->is_ptr()->get_con() < (intptr_t)0x10000, "must be a valid BCI");
652 #ifdef _LP64
653 // Must be restored to the full-width 64-bit stack slot.
654 array->append(new ConstantLongValue(t->is_ptr()->get_con()));
655 #else
656 array->append(new ConstantIntValue(t->is_ptr()->get_con()));
657 #endif
658 break;
659 case Type::FloatCon: {
660 float f = t->is_float_constant()->getf();
661 array->append(new ConstantIntValue(jint_cast(f)));
662 break;
663 }
664 case Type::DoubleCon: {
665 jdouble d = t->is_double_constant()->getd();
666 #ifdef _LP64
667 array->append(new ConstantIntValue((jint)0));
668 array->append(new ConstantDoubleValue(d));
669 #else
670 // Repack the double as two jints.
671 // The convention the interpreter uses is that the second local
672 // holds the first raw word of the native double representation.
673 // This is actually reasonable, since locals and stack arrays
674 // grow downwards in all implementations.
675 // (If, on some machine, the interpreter's Java locals or stack
676 // were to grow upwards, the embedded doubles would be word-swapped.)
677 jlong_accessor acc;
678 acc.long_value = jlong_cast(d);
679 array->append(new ConstantIntValue(acc.words[1]));
680 array->append(new ConstantIntValue(acc.words[0]));
681 #endif
682 break;
683 }
684 case Type::Long: {
685 jlong d = t->is_long()->get_con();
686 #ifdef _LP64
687 array->append(new ConstantIntValue((jint)0));
688 array->append(new ConstantLongValue(d));
689 #else
690 // Repack the long as two jints.
691 // The convention the interpreter uses is that the second local
692 // holds the first raw word of the native double representation.
693 // This is actually reasonable, since locals and stack arrays
694 // grow downwards in all implementations.
695 // (If, on some machine, the interpreter's Java locals or stack
696 // were to grow upwards, the embedded doubles would be word-swapped.)
697 jlong_accessor acc;
698 acc.long_value = d;
699 array->append(new ConstantIntValue(acc.words[1]));
700 array->append(new ConstantIntValue(acc.words[0]));
701 #endif
702 break;
703 }
704 case Type::Top: // Add an illegal value here
705 array->append(new LocationValue(Location()));
706 break;
707 default:
708 ShouldNotReachHere();
709 break;
710 }
711 }
712
713 // Determine if this node starts a bundle
714 bool Compile::starts_bundle(const Node *n) const {
715 return (_node_bundling_limit > n->_idx &&
716 _node_bundling_base[n->_idx].starts_bundle());
717 }
718
719 //--------------------------Process_OopMap_Node--------------------------------
720 void Compile::Process_OopMap_Node(MachNode *mach, int current_offset) {
721
722 // Handle special safepoint nodes for synchronization
723 MachSafePointNode *sfn = mach->as_MachSafePoint();
724 MachCallNode *mcall;
725
726 int safepoint_pc_offset = current_offset;
727 bool is_method_handle_invoke = false;
728 bool return_oop = false;
729 bool return_vt = false;
730
731 // Add the safepoint in the DebugInfoRecorder
732 if( !mach->is_MachCall() ) {
733 mcall = NULL;
734 debug_info()->add_safepoint(safepoint_pc_offset, sfn->_oop_map);
735 } else {
736 mcall = mach->as_MachCall();
737
738 // Is the call a MethodHandle call?
739 if (mcall->is_MachCallJava()) {
740 if (mcall->as_MachCallJava()->_method_handle_invoke) {
741 assert(has_method_handle_invokes(), "must have been set during call generation");
742 is_method_handle_invoke = true;
743 }
744 }
745
746 // Check if a call returns an object.
747 if (mcall->returns_pointer() || mcall->returns_vt()) {
748 return_oop = true;
749 }
750 if (mcall->returns_vt()) {
751 return_vt = true;
752 }
753 safepoint_pc_offset += mcall->ret_addr_offset();
754 debug_info()->add_safepoint(safepoint_pc_offset, mcall->_oop_map);
755 }
756
757 // Loop over the JVMState list to add scope information
758 // Do not skip safepoints with a NULL method, they need monitor info
759 JVMState* youngest_jvms = sfn->jvms();
760 int max_depth = youngest_jvms->depth();
761
762 // Allocate the object pool for scalar-replaced objects -- the map from
763 // small-integer keys (which can be recorded in the local and ostack
764 // arrays) to descriptions of the object state.
765 GrowableArray<ScopeValue*> *objs = new GrowableArray<ScopeValue*>();
766
767 // Visit scopes from oldest to youngest.
768 for (int depth = 1; depth <= max_depth; depth++) {
769 JVMState* jvms = youngest_jvms->of_depth(depth);
770 int idx;
771 ciMethod* method = jvms->has_method() ? jvms->method() : NULL;
772 // Safepoints that do not have method() set only provide oop-map and monitor info
773 // to support GC; these do not support deoptimization.
774 int num_locs = (method == NULL) ? 0 : jvms->loc_size();
775 int num_exps = (method == NULL) ? 0 : jvms->stk_size();
776 int num_mon = jvms->nof_monitors();
777 assert(method == NULL || jvms->bci() < 0 || num_locs == method->max_locals(),
778 "JVMS local count must match that of the method");
779
780 // Add Local and Expression Stack Information
781
782 // Insert locals into the locarray
783 GrowableArray<ScopeValue*> *locarray = new GrowableArray<ScopeValue*>(num_locs);
784 for( idx = 0; idx < num_locs; idx++ ) {
785 FillLocArray( idx, sfn, sfn->local(jvms, idx), locarray, objs );
786 }
787
788 // Insert expression stack entries into the exparray
789 GrowableArray<ScopeValue*> *exparray = new GrowableArray<ScopeValue*>(num_exps);
790 for( idx = 0; idx < num_exps; idx++ ) {
791 FillLocArray( idx, sfn, sfn->stack(jvms, idx), exparray, objs );
792 }
793
794 // Add in mappings of the monitors
795 assert( !method ||
796 !method->is_synchronized() ||
797 method->is_native() ||
798 num_mon > 0 ||
799 !GenerateSynchronizationCode,
800 "monitors must always exist for synchronized methods");
801
802 // Build the growable array of ScopeValues for exp stack
803 GrowableArray<MonitorValue*> *monarray = new GrowableArray<MonitorValue*>(num_mon);
804
805 // Loop over monitors and insert into array
806 for (idx = 0; idx < num_mon; idx++) {
807 // Grab the node that defines this monitor
808 Node* box_node = sfn->monitor_box(jvms, idx);
809 Node* obj_node = sfn->monitor_obj(jvms, idx);
810
811 // Create ScopeValue for object
812 ScopeValue *scval = NULL;
813
814 if (obj_node->is_SafePointScalarObject()) {
815 SafePointScalarObjectNode* spobj = obj_node->as_SafePointScalarObject();
816 scval = Compile::sv_for_node_id(objs, spobj->_idx);
817 if (scval == NULL) {
818 const Type *t = spobj->bottom_type();
819 ciKlass* cik = t->is_oopptr()->klass();
820 assert(cik->is_instance_klass() ||
821 cik->is_array_klass(), "Not supported allocation.");
822 ObjectValue* sv = new ObjectValue(spobj->_idx,
823 new ConstantOopWriteValue(cik->java_mirror()->constant_encoding()));
824 Compile::set_sv_for_object_node(objs, sv);
825
826 uint first_ind = spobj->first_index(youngest_jvms);
827 for (uint i = 0; i < spobj->n_fields(); i++) {
828 Node* fld_node = sfn->in(first_ind+i);
829 (void)FillLocArray(sv->field_values()->length(), sfn, fld_node, sv->field_values(), objs);
830 }
831 scval = sv;
832 }
833 } else if (!obj_node->is_Con()) {
834 OptoReg::Name obj_reg = _regalloc->get_reg_first(obj_node);
835 if( obj_node->bottom_type()->base() == Type::NarrowOop ) {
836 scval = new_loc_value( _regalloc, obj_reg, Location::narrowoop );
837 } else {
838 scval = new_loc_value( _regalloc, obj_reg, Location::oop );
839 }
840 } else {
841 const TypePtr *tp = obj_node->get_ptr_type();
842 scval = new ConstantOopWriteValue(tp->is_oopptr()->const_oop()->constant_encoding());
843 }
844
845 OptoReg::Name box_reg = BoxLockNode::reg(box_node);
846 Location basic_lock = Location::new_stk_loc(Location::normal,_regalloc->reg2offset(box_reg));
847 bool eliminated = (box_node->is_BoxLock() && box_node->as_BoxLock()->is_eliminated());
848 monarray->append(new MonitorValue(scval, basic_lock, eliminated));
849 }
850
851 // We dump the object pool first, since deoptimization reads it in first.
852 debug_info()->dump_object_pool(objs);
853
854 // Build first class objects to pass to scope
855 DebugToken *locvals = debug_info()->create_scope_values(locarray);
856 DebugToken *expvals = debug_info()->create_scope_values(exparray);
857 DebugToken *monvals = debug_info()->create_monitor_values(monarray);
858
859 // Make method available for all Safepoints
860 ciMethod* scope_method = method ? method : _method;
861 // Describe the scope here
862 assert(jvms->bci() >= InvocationEntryBci && jvms->bci() <= 0x10000, "must be a valid or entry BCI");
863 assert(!jvms->should_reexecute() || depth == max_depth, "reexecute allowed only for the youngest");
864 // Now we can describe the scope.
865 methodHandle null_mh;
866 bool rethrow_exception = false;
867 debug_info()->describe_scope(safepoint_pc_offset, null_mh, scope_method, jvms->bci(), jvms->should_reexecute(), rethrow_exception, is_method_handle_invoke, return_oop, return_vt, locvals, expvals, monvals);
868 } // End jvms loop
869
870 // Mark the end of the scope set.
871 debug_info()->end_safepoint(safepoint_pc_offset);
872 }
873
874
875
876 // A simplified version of Process_OopMap_Node, to handle non-safepoints.
877 class NonSafepointEmitter {
878 Compile* C;
879 JVMState* _pending_jvms;
880 int _pending_offset;
881
882 void emit_non_safepoint();
883
884 public:
885 NonSafepointEmitter(Compile* compile) {
886 this->C = compile;
887 _pending_jvms = NULL;
888 _pending_offset = 0;
889 }
890
891 void observe_instruction(Node* n, int pc_offset) {
892 if (!C->debug_info()->recording_non_safepoints()) return;
893
894 Node_Notes* nn = C->node_notes_at(n->_idx);
895 if (nn == NULL || nn->jvms() == NULL) return;
896 if (_pending_jvms != NULL &&
897 _pending_jvms->same_calls_as(nn->jvms())) {
898 // Repeated JVMS? Stretch it up here.
899 _pending_offset = pc_offset;
900 } else {
901 if (_pending_jvms != NULL &&
902 _pending_offset < pc_offset) {
903 emit_non_safepoint();
904 }
905 _pending_jvms = NULL;
906 if (pc_offset > C->debug_info()->last_pc_offset()) {
907 // This is the only way _pending_jvms can become non-NULL:
908 _pending_jvms = nn->jvms();
909 _pending_offset = pc_offset;
910 }
911 }
912 }
913
914 // Stay out of the way of real safepoints:
915 void observe_safepoint(JVMState* jvms, int pc_offset) {
916 if (_pending_jvms != NULL &&
917 !_pending_jvms->same_calls_as(jvms) &&
918 _pending_offset < pc_offset) {
919 emit_non_safepoint();
920 }
921 _pending_jvms = NULL;
922 }
923
924 void flush_at_end() {
925 if (_pending_jvms != NULL) {
926 emit_non_safepoint();
927 }
928 _pending_jvms = NULL;
929 }
930 };
931
932 void NonSafepointEmitter::emit_non_safepoint() {
933 JVMState* youngest_jvms = _pending_jvms;
934 int pc_offset = _pending_offset;
935
936 // Clear it now:
937 _pending_jvms = NULL;
938
939 DebugInformationRecorder* debug_info = C->debug_info();
940 assert(debug_info->recording_non_safepoints(), "sanity");
941
942 debug_info->add_non_safepoint(pc_offset);
943 int max_depth = youngest_jvms->depth();
944
945 // Visit scopes from oldest to youngest.
946 for (int depth = 1; depth <= max_depth; depth++) {
947 JVMState* jvms = youngest_jvms->of_depth(depth);
948 ciMethod* method = jvms->has_method() ? jvms->method() : NULL;
949 assert(!jvms->should_reexecute() || depth==max_depth, "reexecute allowed only for the youngest");
950 methodHandle null_mh;
951 debug_info->describe_scope(pc_offset, null_mh, method, jvms->bci(), jvms->should_reexecute());
952 }
953
954 // Mark the end of the scope set.
955 debug_info->end_non_safepoint(pc_offset);
956 }
957
958 //------------------------------init_buffer------------------------------------
959 CodeBuffer* Compile::init_buffer(uint* blk_starts) {
960
961 // Set the initially allocated size
962 int code_req = initial_code_capacity;
963 int locs_req = initial_locs_capacity;
964 int stub_req = initial_stub_capacity;
965 int const_req = initial_const_capacity;
966
967 int pad_req = NativeCall::instruction_size;
968 // The extra spacing after the code is necessary on some platforms.
969 // Sometimes we need to patch in a jump after the last instruction,
970 // if the nmethod has been deoptimized. (See 4932387, 4894843.)
971
972 // Compute the byte offset where we can store the deopt pc.
973 if (fixed_slots() != 0) {
974 _orig_pc_slot_offset_in_bytes = _regalloc->reg2offset(OptoReg::stack2reg(_orig_pc_slot));
975 }
976
977 // Compute prolog code size
978 _method_size = 0;
979 _frame_slots = OptoReg::reg2stack(_matcher->_old_SP)+_regalloc->_framesize;
980 #if defined(IA64) && !defined(AIX)
981 if (save_argument_registers()) {
982 // 4815101: this is a stub with implicit and unknown precision fp args.
983 // The usual spill mechanism can only generate stfd's in this case, which
984 // doesn't work if the fp reg to spill contains a single-precision denorm.
985 // Instead, we hack around the normal spill mechanism using stfspill's and
986 // ldffill's in the MachProlog and MachEpilog emit methods. We allocate
987 // space here for the fp arg regs (f8-f15) we're going to thusly spill.
988 //
989 // If we ever implement 16-byte 'registers' == stack slots, we can
990 // get rid of this hack and have SpillCopy generate stfspill/ldffill
991 // instead of stfd/stfs/ldfd/ldfs.
992 _frame_slots += 8*(16/BytesPerInt);
993 }
994 #endif
995 assert(_frame_slots >= 0 && _frame_slots < 1000000, "sanity check");
996
997 if (has_mach_constant_base_node()) {
998 uint add_size = 0;
999 // Fill the constant table.
1000 // Note: This must happen before shorten_branches.
1001 for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
1002 Block* b = _cfg->get_block(i);
1003
1004 for (uint j = 0; j < b->number_of_nodes(); j++) {
1005 Node* n = b->get_node(j);
1006
1007 // If the node is a MachConstantNode evaluate the constant
1008 // value section.
1009 if (n->is_MachConstant()) {
1010 MachConstantNode* machcon = n->as_MachConstant();
1011 machcon->eval_constant(C);
1012 } else if (n->is_Mach()) {
1013 // On Power there are more nodes that issue constants.
1014 add_size += (n->as_Mach()->ins_num_consts() * 8);
1015 }
1016 }
1017 }
1018
1019 // Calculate the offsets of the constants and the size of the
1020 // constant table (including the padding to the next section).
1021 constant_table().calculate_offsets_and_size();
1022 const_req = constant_table().size() + add_size;
1023 }
1024
1025 // Initialize the space for the BufferBlob used to find and verify
1026 // instruction size in MachNode::emit_size()
1027 init_scratch_buffer_blob(const_req);
1028 if (failing()) return NULL; // Out of memory
1029
1030 // Pre-compute the length of blocks and replace
1031 // long branches with short if machine supports it.
1032 shorten_branches(blk_starts, code_req, locs_req, stub_req);
1033
1034 // nmethod and CodeBuffer count stubs & constants as part of method's code.
1035 // class HandlerImpl is platform-specific and defined in the *.ad files.
1036 int exception_handler_req = HandlerImpl::size_exception_handler() + MAX_stubs_size; // add marginal slop for handler
1037 int deopt_handler_req = HandlerImpl::size_deopt_handler() + MAX_stubs_size; // add marginal slop for handler
1038 stub_req += MAX_stubs_size; // ensure per-stub margin
1039 code_req += MAX_inst_size; // ensure per-instruction margin
1040
1041 if (StressCodeBuffers)
1042 code_req = const_req = stub_req = exception_handler_req = deopt_handler_req = 0x10; // force expansion
1043
1044 int total_req =
1045 const_req +
1046 code_req +
1047 pad_req +
1048 stub_req +
1049 exception_handler_req +
1050 deopt_handler_req; // deopt handler
1051
1052 if (has_method_handle_invokes())
1053 total_req += deopt_handler_req; // deopt MH handler
1054
1055 CodeBuffer* cb = code_buffer();
1056 cb->initialize(total_req, locs_req);
1057
1058 // Have we run out of code space?
1059 if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1060 C->record_failure("CodeCache is full");
1061 return NULL;
1062 }
1063 // Configure the code buffer.
1064 cb->initialize_consts_size(const_req);
1065 cb->initialize_stubs_size(stub_req);
1066 cb->initialize_oop_recorder(env()->oop_recorder());
1067
1068 // fill in the nop array for bundling computations
1069 MachNode *_nop_list[Bundle::_nop_count];
1070 Bundle::initialize_nops(_nop_list);
1071
1072 return cb;
1073 }
1074
1075 //------------------------------fill_buffer------------------------------------
1076 void Compile::fill_buffer(CodeBuffer* cb, uint* blk_starts) {
1077 // blk_starts[] contains offsets calculated during short branches processing,
1078 // offsets should not be increased during following steps.
1079
1080 // Compute the size of first NumberOfLoopInstrToAlign instructions at head
1081 // of a loop. It is used to determine the padding for loop alignment.
1082 compute_loop_first_inst_sizes();
1083
1084 // Create oopmap set.
1085 _oop_map_set = new OopMapSet();
1086
1087 // !!!!! This preserves old handling of oopmaps for now
1088 debug_info()->set_oopmaps(_oop_map_set);
1089
1090 uint nblocks = _cfg->number_of_blocks();
1091 // Count and start of implicit null check instructions
1092 uint inct_cnt = 0;
1093 uint *inct_starts = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1094
1095 // Count and start of calls
1096 uint *call_returns = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1097
1098 uint return_offset = 0;
1099 int nop_size = (new MachNopNode())->size(_regalloc);
1100
1101 int previous_offset = 0;
1102 int current_offset = 0;
1103 int last_call_offset = -1;
1104 int last_avoid_back_to_back_offset = -1;
1105 #ifdef ASSERT
1106 uint* jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks);
1107 uint* jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
1108 uint* jmp_size = NEW_RESOURCE_ARRAY(uint,nblocks);
1109 uint* jmp_rule = NEW_RESOURCE_ARRAY(uint,nblocks);
1110 #endif
1111
1112 // Create an array of unused labels, one for each basic block, if printing is enabled
1113 #ifndef PRODUCT
1114 int *node_offsets = NULL;
1115 uint node_offset_limit = unique();
1116
1117 if (print_assembly())
1118 node_offsets = NEW_RESOURCE_ARRAY(int, node_offset_limit);
1119 #endif
1120
1121 NonSafepointEmitter non_safepoints(this); // emit non-safepoints lazily
1122
1123 // Emit the constant table.
1124 if (has_mach_constant_base_node()) {
1125 constant_table().emit(*cb);
1126 }
1127
1128 // Create an array of labels, one for each basic block
1129 Label *blk_labels = NEW_RESOURCE_ARRAY(Label, nblocks+1);
1130 for (uint i=0; i <= nblocks; i++) {
1131 blk_labels[i].init();
1132 }
1133
1134 // ------------------
1135 // Now fill in the code buffer
1136 Node *delay_slot = NULL;
1137
1138 for (uint i = 0; i < nblocks; i++) {
1139 Block* block = _cfg->get_block(i);
1140 Node* head = block->head();
1141
1142 // If this block needs to start aligned (i.e, can be reached other
1143 // than by falling-thru from the previous block), then force the
1144 // start of a new bundle.
1145 if (Pipeline::requires_bundling() && starts_bundle(head)) {
1146 cb->flush_bundle(true);
1147 }
1148
1149 #ifdef ASSERT
1150 if (!block->is_connector()) {
1151 stringStream st;
1152 block->dump_head(_cfg, &st);
1153 MacroAssembler(cb).block_comment(st.as_string());
1154 }
1155 jmp_target[i] = 0;
1156 jmp_offset[i] = 0;
1157 jmp_size[i] = 0;
1158 jmp_rule[i] = 0;
1159 #endif
1160 int blk_offset = current_offset;
1161
1162 // Define the label at the beginning of the basic block
1163 MacroAssembler(cb).bind(blk_labels[block->_pre_order]);
1164
1165 uint last_inst = block->number_of_nodes();
1166
1167 // Emit block normally, except for last instruction.
1168 // Emit means "dump code bits into code buffer".
1169 for (uint j = 0; j<last_inst; j++) {
1170
1171 // Get the node
1172 Node* n = block->get_node(j);
1173
1174 // See if delay slots are supported
1175 if (valid_bundle_info(n) &&
1176 node_bundling(n)->used_in_unconditional_delay()) {
1177 assert(delay_slot == NULL, "no use of delay slot node");
1178 assert(n->size(_regalloc) == Pipeline::instr_unit_size(), "delay slot instruction wrong size");
1179
1180 delay_slot = n;
1181 continue;
1182 }
1183
1184 // If this starts a new instruction group, then flush the current one
1185 // (but allow split bundles)
1186 if (Pipeline::requires_bundling() && starts_bundle(n))
1187 cb->flush_bundle(false);
1188
1189 // Special handling for SafePoint/Call Nodes
1190 bool is_mcall = false;
1191 if (n->is_Mach()) {
1192 MachNode *mach = n->as_Mach();
1193 is_mcall = n->is_MachCall();
1194 bool is_sfn = n->is_MachSafePoint();
1195
1196 // If this requires all previous instructions be flushed, then do so
1197 if (is_sfn || is_mcall || mach->alignment_required() != 1) {
1198 cb->flush_bundle(true);
1199 current_offset = cb->insts_size();
1200 }
1201
1202 // A padding may be needed again since a previous instruction
1203 // could be moved to delay slot.
1204
1205 // align the instruction if necessary
1206 int padding = mach->compute_padding(current_offset);
1207 // Make sure safepoint node for polling is distinct from a call's
1208 // return by adding a nop if needed.
1209 if (is_sfn && !is_mcall && padding == 0 && current_offset == last_call_offset) {
1210 padding = nop_size;
1211 }
1212 if (padding == 0 && mach->avoid_back_to_back(MachNode::AVOID_BEFORE) &&
1213 current_offset == last_avoid_back_to_back_offset) {
1214 // Avoid back to back some instructions.
1215 padding = nop_size;
1216 }
1217
1218 if (padding > 0) {
1219 assert((padding % nop_size) == 0, "padding is not a multiple of NOP size");
1220 int nops_cnt = padding / nop_size;
1221 MachNode *nop = new MachNopNode(nops_cnt);
1222 block->insert_node(nop, j++);
1223 last_inst++;
1224 _cfg->map_node_to_block(nop, block);
1225 // Ensure enough space.
1226 cb->insts()->maybe_expand_to_ensure_remaining(MAX_inst_size);
1227 if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1228 C->record_failure("CodeCache is full");
1229 return;
1230 }
1231 nop->emit(*cb, _regalloc);
1232 cb->flush_bundle(true);
1233 current_offset = cb->insts_size();
1234 }
1235
1236 // Remember the start of the last call in a basic block
1237 if (is_mcall) {
1238 MachCallNode *mcall = mach->as_MachCall();
1239
1240 if (mcall->entry_point() != NULL) {
1241 // This destination address is NOT PC-relative
1242 mcall->method_set((intptr_t)mcall->entry_point());
1243 }
1244
1245 // Save the return address
1246 call_returns[block->_pre_order] = current_offset + mcall->ret_addr_offset();
1247
1248 if (mcall->is_MachCallLeaf()) {
1249 is_mcall = false;
1250 is_sfn = false;
1251 }
1252 }
1253
1254 // sfn will be valid whenever mcall is valid now because of inheritance
1255 if (is_sfn || is_mcall) {
1256
1257 // Handle special safepoint nodes for synchronization
1258 if (!is_mcall) {
1259 MachSafePointNode *sfn = mach->as_MachSafePoint();
1260 // !!!!! Stubs only need an oopmap right now, so bail out
1261 if (sfn->jvms()->method() == NULL) {
1262 // Write the oopmap directly to the code blob??!!
1263 continue;
1264 }
1265 } // End synchronization
1266
1267 non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1268 current_offset);
1269 Process_OopMap_Node(mach, current_offset);
1270 } // End if safepoint
1271
1272 // If this is a null check, then add the start of the previous instruction to the list
1273 else if( mach->is_MachNullCheck() ) {
1274 inct_starts[inct_cnt++] = previous_offset;
1275 }
1276
1277 // If this is a branch, then fill in the label with the target BB's label
1278 else if (mach->is_MachBranch()) {
1279 // This requires the TRUE branch target be in succs[0]
1280 uint block_num = block->non_connector_successor(0)->_pre_order;
1281
1282 // Try to replace long branch if delay slot is not used,
1283 // it is mostly for back branches since forward branch's
1284 // distance is not updated yet.
1285 bool delay_slot_is_used = valid_bundle_info(n) &&
1286 node_bundling(n)->use_unconditional_delay();
1287 if (!delay_slot_is_used && mach->may_be_short_branch()) {
1288 assert(delay_slot == NULL, "not expecting delay slot node");
1289 int br_size = n->size(_regalloc);
1290 int offset = blk_starts[block_num] - current_offset;
1291 if (block_num >= i) {
1292 // Current and following block's offset are not
1293 // finalized yet, adjust distance by the difference
1294 // between calculated and final offsets of current block.
1295 offset -= (blk_starts[i] - blk_offset);
1296 }
1297 // In the following code a nop could be inserted before
1298 // the branch which will increase the backward distance.
1299 bool needs_padding = (current_offset == last_avoid_back_to_back_offset);
1300 if (needs_padding && offset <= 0)
1301 offset -= nop_size;
1302
1303 if (_matcher->is_short_branch_offset(mach->rule(), br_size, offset)) {
1304 // We've got a winner. Replace this branch.
1305 MachNode* replacement = mach->as_MachBranch()->short_branch_version();
1306
1307 // Update the jmp_size.
1308 int new_size = replacement->size(_regalloc);
1309 assert((br_size - new_size) >= (int)nop_size, "short_branch size should be smaller");
1310 // Insert padding between avoid_back_to_back branches.
1311 if (needs_padding && replacement->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
1312 MachNode *nop = new MachNopNode();
1313 block->insert_node(nop, j++);
1314 _cfg->map_node_to_block(nop, block);
1315 last_inst++;
1316 nop->emit(*cb, _regalloc);
1317 cb->flush_bundle(true);
1318 current_offset = cb->insts_size();
1319 }
1320 #ifdef ASSERT
1321 jmp_target[i] = block_num;
1322 jmp_offset[i] = current_offset - blk_offset;
1323 jmp_size[i] = new_size;
1324 jmp_rule[i] = mach->rule();
1325 #endif
1326 block->map_node(replacement, j);
1327 mach->subsume_by(replacement, C);
1328 n = replacement;
1329 mach = replacement;
1330 }
1331 }
1332 mach->as_MachBranch()->label_set( &blk_labels[block_num], block_num );
1333 } else if (mach->ideal_Opcode() == Op_Jump) {
1334 for (uint h = 0; h < block->_num_succs; h++) {
1335 Block* succs_block = block->_succs[h];
1336 for (uint j = 1; j < succs_block->num_preds(); j++) {
1337 Node* jpn = succs_block->pred(j);
1338 if (jpn->is_JumpProj() && jpn->in(0) == mach) {
1339 uint block_num = succs_block->non_connector()->_pre_order;
1340 Label *blkLabel = &blk_labels[block_num];
1341 mach->add_case_label(jpn->as_JumpProj()->proj_no(), blkLabel);
1342 }
1343 }
1344 }
1345 }
1346 #ifdef ASSERT
1347 // Check that oop-store precedes the card-mark
1348 else if (mach->ideal_Opcode() == Op_StoreCM) {
1349 uint storeCM_idx = j;
1350 int count = 0;
1351 for (uint prec = mach->req(); prec < mach->len(); prec++) {
1352 Node *oop_store = mach->in(prec); // Precedence edge
1353 if (oop_store == NULL) continue;
1354 count++;
1355 uint i4;
1356 for (i4 = 0; i4 < last_inst; ++i4) {
1357 if (block->get_node(i4) == oop_store) {
1358 break;
1359 }
1360 }
1361 // Note: This test can provide a false failure if other precedence
1362 // edges have been added to the storeCMNode.
1363 assert(i4 == last_inst || i4 < storeCM_idx, "CM card-mark executes before oop-store");
1364 }
1365 assert(count > 0, "storeCM expects at least one precedence edge");
1366 }
1367 #endif
1368 else if (!n->is_Proj()) {
1369 // Remember the beginning of the previous instruction, in case
1370 // it's followed by a flag-kill and a null-check. Happens on
1371 // Intel all the time, with add-to-memory kind of opcodes.
1372 previous_offset = current_offset;
1373 }
1374
1375 // Not an else-if!
1376 // If this is a trap based cmp then add its offset to the list.
1377 if (mach->is_TrapBasedCheckNode()) {
1378 inct_starts[inct_cnt++] = current_offset;
1379 }
1380 }
1381
1382 // Verify that there is sufficient space remaining
1383 cb->insts()->maybe_expand_to_ensure_remaining(MAX_inst_size);
1384 if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1385 C->record_failure("CodeCache is full");
1386 return;
1387 }
1388
1389 // Save the offset for the listing
1390 #ifndef PRODUCT
1391 if (node_offsets && n->_idx < node_offset_limit)
1392 node_offsets[n->_idx] = cb->insts_size();
1393 #endif
1394
1395 // "Normal" instruction case
1396 DEBUG_ONLY( uint instr_offset = cb->insts_size(); )
1397 n->emit(*cb, _regalloc);
1398 current_offset = cb->insts_size();
1399
1400 // Above we only verified that there is enough space in the instruction section.
1401 // However, the instruction may emit stubs that cause code buffer expansion.
1402 // Bail out here if expansion failed due to a lack of code cache space.
1403 if (failing()) {
1404 return;
1405 }
1406
1407 #ifdef ASSERT
1408 if (n->size(_regalloc) < (current_offset-instr_offset)) {
1409 n->dump();
1410 assert(false, "wrong size of mach node");
1411 }
1412 #endif
1413 non_safepoints.observe_instruction(n, current_offset);
1414
1415 // mcall is last "call" that can be a safepoint
1416 // record it so we can see if a poll will directly follow it
1417 // in which case we'll need a pad to make the PcDesc sites unique
1418 // see 5010568. This can be slightly inaccurate but conservative
1419 // in the case that return address is not actually at current_offset.
1420 // This is a small price to pay.
1421
1422 if (is_mcall) {
1423 last_call_offset = current_offset;
1424 }
1425
1426 if (n->is_Mach() && n->as_Mach()->avoid_back_to_back(MachNode::AVOID_AFTER)) {
1427 // Avoid back to back some instructions.
1428 last_avoid_back_to_back_offset = current_offset;
1429 }
1430
1431 // See if this instruction has a delay slot
1432 if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
1433 guarantee(delay_slot != NULL, "expecting delay slot node");
1434
1435 // Back up 1 instruction
1436 cb->set_insts_end(cb->insts_end() - Pipeline::instr_unit_size());
1437
1438 // Save the offset for the listing
1439 #ifndef PRODUCT
1440 if (node_offsets && delay_slot->_idx < node_offset_limit)
1441 node_offsets[delay_slot->_idx] = cb->insts_size();
1442 #endif
1443
1444 // Support a SafePoint in the delay slot
1445 if (delay_slot->is_MachSafePoint()) {
1446 MachNode *mach = delay_slot->as_Mach();
1447 // !!!!! Stubs only need an oopmap right now, so bail out
1448 if (!mach->is_MachCall() && mach->as_MachSafePoint()->jvms()->method() == NULL) {
1449 // Write the oopmap directly to the code blob??!!
1450 delay_slot = NULL;
1451 continue;
1452 }
1453
1454 int adjusted_offset = current_offset - Pipeline::instr_unit_size();
1455 non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1456 adjusted_offset);
1457 // Generate an OopMap entry
1458 Process_OopMap_Node(mach, adjusted_offset);
1459 }
1460
1461 // Insert the delay slot instruction
1462 delay_slot->emit(*cb, _regalloc);
1463
1464 // Don't reuse it
1465 delay_slot = NULL;
1466 }
1467
1468 } // End for all instructions in block
1469
1470 // If the next block is the top of a loop, pad this block out to align
1471 // the loop top a little. Helps prevent pipe stalls at loop back branches.
1472 if (i < nblocks-1) {
1473 Block *nb = _cfg->get_block(i + 1);
1474 int padding = nb->alignment_padding(current_offset);
1475 if( padding > 0 ) {
1476 MachNode *nop = new MachNopNode(padding / nop_size);
1477 block->insert_node(nop, block->number_of_nodes());
1478 _cfg->map_node_to_block(nop, block);
1479 nop->emit(*cb, _regalloc);
1480 current_offset = cb->insts_size();
1481 }
1482 }
1483 // Verify that the distance for generated before forward
1484 // short branches is still valid.
1485 guarantee((int)(blk_starts[i+1] - blk_starts[i]) >= (current_offset - blk_offset), "shouldn't increase block size");
1486
1487 // Save new block start offset
1488 blk_starts[i] = blk_offset;
1489 } // End of for all blocks
1490 blk_starts[nblocks] = current_offset;
1491
1492 non_safepoints.flush_at_end();
1493
1494 // Offset too large?
1495 if (failing()) return;
1496
1497 // Define a pseudo-label at the end of the code
1498 MacroAssembler(cb).bind( blk_labels[nblocks] );
1499
1500 // Compute the size of the first block
1501 _first_block_size = blk_labels[1].loc_pos() - blk_labels[0].loc_pos();
1502
1503 #ifdef ASSERT
1504 for (uint i = 0; i < nblocks; i++) { // For all blocks
1505 if (jmp_target[i] != 0) {
1506 int br_size = jmp_size[i];
1507 int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
1508 if (!_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
1509 tty->print_cr("target (%d) - jmp_offset(%d) = offset (%d), jump_size(%d), jmp_block B%d, target_block B%d", blk_starts[jmp_target[i]], blk_starts[i] + jmp_offset[i], offset, br_size, i, jmp_target[i]);
1510 assert(false, "Displacement too large for short jmp");
1511 }
1512 }
1513 }
1514 #endif
1515
1516 #ifndef PRODUCT
1517 // Information on the size of the method, without the extraneous code
1518 Scheduling::increment_method_size(cb->insts_size());
1519 #endif
1520
1521 // ------------------
1522 // Fill in exception table entries.
1523 FillExceptionTables(inct_cnt, call_returns, inct_starts, blk_labels);
1524
1525 // Only java methods have exception handlers and deopt handlers
1526 // class HandlerImpl is platform-specific and defined in the *.ad files.
1527 if (_method) {
1528 // Emit the exception handler code.
1529 _code_offsets.set_value(CodeOffsets::Exceptions, HandlerImpl::emit_exception_handler(*cb));
1530 if (failing()) {
1531 return; // CodeBuffer::expand failed
1532 }
1533 // Emit the deopt handler code.
1534 _code_offsets.set_value(CodeOffsets::Deopt, HandlerImpl::emit_deopt_handler(*cb));
1535
1536 // Emit the MethodHandle deopt handler code (if required).
1537 if (has_method_handle_invokes() && !failing()) {
1538 // We can use the same code as for the normal deopt handler, we
1539 // just need a different entry point address.
1540 _code_offsets.set_value(CodeOffsets::DeoptMH, HandlerImpl::emit_deopt_handler(*cb));
1541 }
1542 }
1543
1544 // One last check for failed CodeBuffer::expand:
1545 if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1546 C->record_failure("CodeCache is full");
1547 return;
1548 }
1549
1550 #ifndef PRODUCT
1551 // Dump the assembly code, including basic-block numbers
1552 if (print_assembly()) {
1553 ttyLocker ttyl; // keep the following output all in one block
1554 if (!VMThread::should_terminate()) { // test this under the tty lock
1555 // This output goes directly to the tty, not the compiler log.
1556 // To enable tools to match it up with the compilation activity,
1557 // be sure to tag this tty output with the compile ID.
1558 if (xtty != NULL) {
1559 xtty->head("opto_assembly compile_id='%d'%s", compile_id(),
1560 is_osr_compilation() ? " compile_kind='osr'" :
1561 "");
1562 }
1563 if (method() != NULL) {
1564 method()->print_metadata();
1565 }
1566 dump_asm(node_offsets, node_offset_limit);
1567 if (xtty != NULL) {
1568 // print_metadata and dump_asm above may safepoint which makes us loose the ttylock.
1569 // Retake lock too make sure the end tag is coherent, and that xmlStream->pop_tag is done
1570 // thread safe
1571 ttyLocker ttyl2;
1572 xtty->tail("opto_assembly");
1573 }
1574 }
1575 }
1576 #endif
1577
1578 }
1579
1580 void Compile::FillExceptionTables(uint cnt, uint *call_returns, uint *inct_starts, Label *blk_labels) {
1581 _inc_table.set_size(cnt);
1582
1583 uint inct_cnt = 0;
1584 for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
1585 Block* block = _cfg->get_block(i);
1586 Node *n = NULL;
1587 int j;
1588
1589 // Find the branch; ignore trailing NOPs.
1590 for (j = block->number_of_nodes() - 1; j >= 0; j--) {
1591 n = block->get_node(j);
1592 if (!n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con) {
1593 break;
1594 }
1595 }
1596
1597 // If we didn't find anything, continue
1598 if (j < 0) {
1599 continue;
1600 }
1601
1602 // Compute ExceptionHandlerTable subtable entry and add it
1603 // (skip empty blocks)
1604 if (n->is_Catch()) {
1605
1606 // Get the offset of the return from the call
1607 uint call_return = call_returns[block->_pre_order];
1608 #ifdef ASSERT
1609 assert( call_return > 0, "no call seen for this basic block" );
1610 while (block->get_node(--j)->is_MachProj()) ;
1611 assert(block->get_node(j)->is_MachCall(), "CatchProj must follow call");
1612 #endif
1613 // last instruction is a CatchNode, find it's CatchProjNodes
1614 int nof_succs = block->_num_succs;
1615 // allocate space
1616 GrowableArray<intptr_t> handler_bcis(nof_succs);
1617 GrowableArray<intptr_t> handler_pcos(nof_succs);
1618 // iterate through all successors
1619 for (int j = 0; j < nof_succs; j++) {
1620 Block* s = block->_succs[j];
1621 bool found_p = false;
1622 for (uint k = 1; k < s->num_preds(); k++) {
1623 Node* pk = s->pred(k);
1624 if (pk->is_CatchProj() && pk->in(0) == n) {
1625 const CatchProjNode* p = pk->as_CatchProj();
1626 found_p = true;
1627 // add the corresponding handler bci & pco information
1628 if (p->_con != CatchProjNode::fall_through_index) {
1629 // p leads to an exception handler (and is not fall through)
1630 assert(s == _cfg->get_block(s->_pre_order), "bad numbering");
1631 // no duplicates, please
1632 if (!handler_bcis.contains(p->handler_bci())) {
1633 uint block_num = s->non_connector()->_pre_order;
1634 handler_bcis.append(p->handler_bci());
1635 handler_pcos.append(blk_labels[block_num].loc_pos());
1636 }
1637 }
1638 }
1639 }
1640 assert(found_p, "no matching predecessor found");
1641 // Note: Due to empty block removal, one block may have
1642 // several CatchProj inputs, from the same Catch.
1643 }
1644
1645 // Set the offset of the return from the call
1646 assert(handler_bcis.find(-1) != -1, "must have default handler");
1647 _handler_table.add_subtable(call_return, &handler_bcis, NULL, &handler_pcos);
1648 continue;
1649 }
1650
1651 // Handle implicit null exception table updates
1652 if (n->is_MachNullCheck()) {
1653 uint block_num = block->non_connector_successor(0)->_pre_order;
1654 _inc_table.append(inct_starts[inct_cnt++], blk_labels[block_num].loc_pos());
1655 continue;
1656 }
1657 // Handle implicit exception table updates: trap instructions.
1658 if (n->is_Mach() && n->as_Mach()->is_TrapBasedCheckNode()) {
1659 uint block_num = block->non_connector_successor(0)->_pre_order;
1660 _inc_table.append(inct_starts[inct_cnt++], blk_labels[block_num].loc_pos());
1661 continue;
1662 }
1663 } // End of for all blocks fill in exception table entries
1664 }
1665
1666 // Static Variables
1667 #ifndef PRODUCT
1668 uint Scheduling::_total_nop_size = 0;
1669 uint Scheduling::_total_method_size = 0;
1670 uint Scheduling::_total_branches = 0;
1671 uint Scheduling::_total_unconditional_delays = 0;
1672 uint Scheduling::_total_instructions_per_bundle[Pipeline::_max_instrs_per_cycle+1];
1673 #endif
1674
1675 // Initializer for class Scheduling
1676
1677 Scheduling::Scheduling(Arena *arena, Compile &compile)
1678 : _arena(arena),
1679 _cfg(compile.cfg()),
1680 _regalloc(compile.regalloc()),
1681 _scheduled(arena),
1682 _available(arena),
1683 _reg_node(arena),
1684 _pinch_free_list(arena),
1685 _next_node(NULL),
1686 _bundle_instr_count(0),
1687 _bundle_cycle_number(0),
1688 _bundle_use(0, 0, resource_count, &_bundle_use_elements[0])
1689 #ifndef PRODUCT
1690 , _branches(0)
1691 , _unconditional_delays(0)
1692 #endif
1693 {
1694 // Create a MachNopNode
1695 _nop = new MachNopNode();
1696
1697 // Now that the nops are in the array, save the count
1698 // (but allow entries for the nops)
1699 _node_bundling_limit = compile.unique();
1700 uint node_max = _regalloc->node_regs_max_index();
1701
1702 compile.set_node_bundling_limit(_node_bundling_limit);
1703
1704 // This one is persistent within the Compile class
1705 _node_bundling_base = NEW_ARENA_ARRAY(compile.comp_arena(), Bundle, node_max);
1706
1707 // Allocate space for fixed-size arrays
1708 _node_latency = NEW_ARENA_ARRAY(arena, unsigned short, node_max);
1709 _uses = NEW_ARENA_ARRAY(arena, short, node_max);
1710 _current_latency = NEW_ARENA_ARRAY(arena, unsigned short, node_max);
1711
1712 // Clear the arrays
1713 memset(_node_bundling_base, 0, node_max * sizeof(Bundle));
1714 memset(_node_latency, 0, node_max * sizeof(unsigned short));
1715 memset(_uses, 0, node_max * sizeof(short));
1716 memset(_current_latency, 0, node_max * sizeof(unsigned short));
1717
1718 // Clear the bundling information
1719 memcpy(_bundle_use_elements, Pipeline_Use::elaborated_elements, sizeof(Pipeline_Use::elaborated_elements));
1720
1721 // Get the last node
1722 Block* block = _cfg->get_block(_cfg->number_of_blocks() - 1);
1723
1724 _next_node = block->get_node(block->number_of_nodes() - 1);
1725 }
1726
1727 #ifndef PRODUCT
1728 // Scheduling destructor
1729 Scheduling::~Scheduling() {
1730 _total_branches += _branches;
1731 _total_unconditional_delays += _unconditional_delays;
1732 }
1733 #endif
1734
1735 // Step ahead "i" cycles
1736 void Scheduling::step(uint i) {
1737
1738 Bundle *bundle = node_bundling(_next_node);
1739 bundle->set_starts_bundle();
1740
1741 // Update the bundle record, but leave the flags information alone
1742 if (_bundle_instr_count > 0) {
1743 bundle->set_instr_count(_bundle_instr_count);
1744 bundle->set_resources_used(_bundle_use.resourcesUsed());
1745 }
1746
1747 // Update the state information
1748 _bundle_instr_count = 0;
1749 _bundle_cycle_number += i;
1750 _bundle_use.step(i);
1751 }
1752
1753 void Scheduling::step_and_clear() {
1754 Bundle *bundle = node_bundling(_next_node);
1755 bundle->set_starts_bundle();
1756
1757 // Update the bundle record
1758 if (_bundle_instr_count > 0) {
1759 bundle->set_instr_count(_bundle_instr_count);
1760 bundle->set_resources_used(_bundle_use.resourcesUsed());
1761
1762 _bundle_cycle_number += 1;
1763 }
1764
1765 // Clear the bundling information
1766 _bundle_instr_count = 0;
1767 _bundle_use.reset();
1768
1769 memcpy(_bundle_use_elements,
1770 Pipeline_Use::elaborated_elements,
1771 sizeof(Pipeline_Use::elaborated_elements));
1772 }
1773
1774 // Perform instruction scheduling and bundling over the sequence of
1775 // instructions in backwards order.
1776 void Compile::ScheduleAndBundle() {
1777
1778 // Don't optimize this if it isn't a method
1779 if (!_method)
1780 return;
1781
1782 // Don't optimize this if scheduling is disabled
1783 if (!do_scheduling())
1784 return;
1785
1786 // Scheduling code works only with pairs (16 bytes) maximum.
1787 if (max_vector_size() > 16)
1788 return;
1789
1790 TracePhase tp("isched", &timers[_t_instrSched]);
1791
1792 // Create a data structure for all the scheduling information
1793 Scheduling scheduling(Thread::current()->resource_area(), *this);
1794
1795 // Walk backwards over each basic block, computing the needed alignment
1796 // Walk over all the basic blocks
1797 scheduling.DoScheduling();
1798 }
1799
1800 // Compute the latency of all the instructions. This is fairly simple,
1801 // because we already have a legal ordering. Walk over the instructions
1802 // from first to last, and compute the latency of the instruction based
1803 // on the latency of the preceding instruction(s).
1804 void Scheduling::ComputeLocalLatenciesForward(const Block *bb) {
1805 #ifndef PRODUCT
1806 if (_cfg->C->trace_opto_output())
1807 tty->print("# -> ComputeLocalLatenciesForward\n");
1808 #endif
1809
1810 // Walk over all the schedulable instructions
1811 for( uint j=_bb_start; j < _bb_end; j++ ) {
1812
1813 // This is a kludge, forcing all latency calculations to start at 1.
1814 // Used to allow latency 0 to force an instruction to the beginning
1815 // of the bb
1816 uint latency = 1;
1817 Node *use = bb->get_node(j);
1818 uint nlen = use->len();
1819
1820 // Walk over all the inputs
1821 for ( uint k=0; k < nlen; k++ ) {
1822 Node *def = use->in(k);
1823 if (!def)
1824 continue;
1825
1826 uint l = _node_latency[def->_idx] + use->latency(k);
1827 if (latency < l)
1828 latency = l;
1829 }
1830
1831 _node_latency[use->_idx] = latency;
1832
1833 #ifndef PRODUCT
1834 if (_cfg->C->trace_opto_output()) {
1835 tty->print("# latency %4d: ", latency);
1836 use->dump();
1837 }
1838 #endif
1839 }
1840
1841 #ifndef PRODUCT
1842 if (_cfg->C->trace_opto_output())
1843 tty->print("# <- ComputeLocalLatenciesForward\n");
1844 #endif
1845
1846 } // end ComputeLocalLatenciesForward
1847
1848 // See if this node fits into the present instruction bundle
1849 bool Scheduling::NodeFitsInBundle(Node *n) {
1850 uint n_idx = n->_idx;
1851
1852 // If this is the unconditional delay instruction, then it fits
1853 if (n == _unconditional_delay_slot) {
1854 #ifndef PRODUCT
1855 if (_cfg->C->trace_opto_output())
1856 tty->print("# NodeFitsInBundle [%4d]: TRUE; is in unconditional delay slot\n", n->_idx);
1857 #endif
1858 return (true);
1859 }
1860
1861 // If the node cannot be scheduled this cycle, skip it
1862 if (_current_latency[n_idx] > _bundle_cycle_number) {
1863 #ifndef PRODUCT
1864 if (_cfg->C->trace_opto_output())
1865 tty->print("# NodeFitsInBundle [%4d]: FALSE; latency %4d > %d\n",
1866 n->_idx, _current_latency[n_idx], _bundle_cycle_number);
1867 #endif
1868 return (false);
1869 }
1870
1871 const Pipeline *node_pipeline = n->pipeline();
1872
1873 uint instruction_count = node_pipeline->instructionCount();
1874 if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
1875 instruction_count = 0;
1876 else if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
1877 instruction_count++;
1878
1879 if (_bundle_instr_count + instruction_count > Pipeline::_max_instrs_per_cycle) {
1880 #ifndef PRODUCT
1881 if (_cfg->C->trace_opto_output())
1882 tty->print("# NodeFitsInBundle [%4d]: FALSE; too many instructions: %d > %d\n",
1883 n->_idx, _bundle_instr_count + instruction_count, Pipeline::_max_instrs_per_cycle);
1884 #endif
1885 return (false);
1886 }
1887
1888 // Don't allow non-machine nodes to be handled this way
1889 if (!n->is_Mach() && instruction_count == 0)
1890 return (false);
1891
1892 // See if there is any overlap
1893 uint delay = _bundle_use.full_latency(0, node_pipeline->resourceUse());
1894
1895 if (delay > 0) {
1896 #ifndef PRODUCT
1897 if (_cfg->C->trace_opto_output())
1898 tty->print("# NodeFitsInBundle [%4d]: FALSE; functional units overlap\n", n_idx);
1899 #endif
1900 return false;
1901 }
1902
1903 #ifndef PRODUCT
1904 if (_cfg->C->trace_opto_output())
1905 tty->print("# NodeFitsInBundle [%4d]: TRUE\n", n_idx);
1906 #endif
1907
1908 return true;
1909 }
1910
1911 Node * Scheduling::ChooseNodeToBundle() {
1912 uint siz = _available.size();
1913
1914 if (siz == 0) {
1915
1916 #ifndef PRODUCT
1917 if (_cfg->C->trace_opto_output())
1918 tty->print("# ChooseNodeToBundle: NULL\n");
1919 #endif
1920 return (NULL);
1921 }
1922
1923 // Fast path, if only 1 instruction in the bundle
1924 if (siz == 1) {
1925 #ifndef PRODUCT
1926 if (_cfg->C->trace_opto_output()) {
1927 tty->print("# ChooseNodeToBundle (only 1): ");
1928 _available[0]->dump();
1929 }
1930 #endif
1931 return (_available[0]);
1932 }
1933
1934 // Don't bother, if the bundle is already full
1935 if (_bundle_instr_count < Pipeline::_max_instrs_per_cycle) {
1936 for ( uint i = 0; i < siz; i++ ) {
1937 Node *n = _available[i];
1938
1939 // Skip projections, we'll handle them another way
1940 if (n->is_Proj())
1941 continue;
1942
1943 // This presupposed that instructions are inserted into the
1944 // available list in a legality order; i.e. instructions that
1945 // must be inserted first are at the head of the list
1946 if (NodeFitsInBundle(n)) {
1947 #ifndef PRODUCT
1948 if (_cfg->C->trace_opto_output()) {
1949 tty->print("# ChooseNodeToBundle: ");
1950 n->dump();
1951 }
1952 #endif
1953 return (n);
1954 }
1955 }
1956 }
1957
1958 // Nothing fits in this bundle, choose the highest priority
1959 #ifndef PRODUCT
1960 if (_cfg->C->trace_opto_output()) {
1961 tty->print("# ChooseNodeToBundle: ");
1962 _available[0]->dump();
1963 }
1964 #endif
1965
1966 return _available[0];
1967 }
1968
1969 void Scheduling::AddNodeToAvailableList(Node *n) {
1970 assert( !n->is_Proj(), "projections never directly made available" );
1971 #ifndef PRODUCT
1972 if (_cfg->C->trace_opto_output()) {
1973 tty->print("# AddNodeToAvailableList: ");
1974 n->dump();
1975 }
1976 #endif
1977
1978 int latency = _current_latency[n->_idx];
1979
1980 // Insert in latency order (insertion sort)
1981 uint i;
1982 for ( i=0; i < _available.size(); i++ )
1983 if (_current_latency[_available[i]->_idx] > latency)
1984 break;
1985
1986 // Special Check for compares following branches
1987 if( n->is_Mach() && _scheduled.size() > 0 ) {
1988 int op = n->as_Mach()->ideal_Opcode();
1989 Node *last = _scheduled[0];
1990 if( last->is_MachIf() && last->in(1) == n &&
1991 ( op == Op_CmpI ||
1992 op == Op_CmpU ||
1993 op == Op_CmpUL ||
1994 op == Op_CmpP ||
1995 op == Op_CmpF ||
1996 op == Op_CmpD ||
1997 op == Op_CmpL ) ) {
1998
1999 // Recalculate position, moving to front of same latency
2000 for ( i=0 ; i < _available.size(); i++ )
2001 if (_current_latency[_available[i]->_idx] >= latency)
2002 break;
2003 }
2004 }
2005
2006 // Insert the node in the available list
2007 _available.insert(i, n);
2008
2009 #ifndef PRODUCT
2010 if (_cfg->C->trace_opto_output())
2011 dump_available();
2012 #endif
2013 }
2014
2015 void Scheduling::DecrementUseCounts(Node *n, const Block *bb) {
2016 for ( uint i=0; i < n->len(); i++ ) {
2017 Node *def = n->in(i);
2018 if (!def) continue;
2019 if( def->is_Proj() ) // If this is a machine projection, then
2020 def = def->in(0); // propagate usage thru to the base instruction
2021
2022 if(_cfg->get_block_for_node(def) != bb) { // Ignore if not block-local
2023 continue;
2024 }
2025
2026 // Compute the latency
2027 uint l = _bundle_cycle_number + n->latency(i);
2028 if (_current_latency[def->_idx] < l)
2029 _current_latency[def->_idx] = l;
2030
2031 // If this does not have uses then schedule it
2032 if ((--_uses[def->_idx]) == 0)
2033 AddNodeToAvailableList(def);
2034 }
2035 }
2036
2037 void Scheduling::AddNodeToBundle(Node *n, const Block *bb) {
2038 #ifndef PRODUCT
2039 if (_cfg->C->trace_opto_output()) {
2040 tty->print("# AddNodeToBundle: ");
2041 n->dump();
2042 }
2043 #endif
2044
2045 // Remove this from the available list
2046 uint i;
2047 for (i = 0; i < _available.size(); i++)
2048 if (_available[i] == n)
2049 break;
2050 assert(i < _available.size(), "entry in _available list not found");
2051 _available.remove(i);
2052
2053 // See if this fits in the current bundle
2054 const Pipeline *node_pipeline = n->pipeline();
2055 const Pipeline_Use& node_usage = node_pipeline->resourceUse();
2056
2057 // Check for instructions to be placed in the delay slot. We
2058 // do this before we actually schedule the current instruction,
2059 // because the delay slot follows the current instruction.
2060 if (Pipeline::_branch_has_delay_slot &&
2061 node_pipeline->hasBranchDelay() &&
2062 !_unconditional_delay_slot) {
2063
2064 uint siz = _available.size();
2065
2066 // Conditional branches can support an instruction that
2067 // is unconditionally executed and not dependent by the
2068 // branch, OR a conditionally executed instruction if
2069 // the branch is taken. In practice, this means that
2070 // the first instruction at the branch target is
2071 // copied to the delay slot, and the branch goes to
2072 // the instruction after that at the branch target
2073 if ( n->is_MachBranch() ) {
2074
2075 assert( !n->is_MachNullCheck(), "should not look for delay slot for Null Check" );
2076 assert( !n->is_Catch(), "should not look for delay slot for Catch" );
2077
2078 #ifndef PRODUCT
2079 _branches++;
2080 #endif
2081
2082 // At least 1 instruction is on the available list
2083 // that is not dependent on the branch
2084 for (uint i = 0; i < siz; i++) {
2085 Node *d = _available[i];
2086 const Pipeline *avail_pipeline = d->pipeline();
2087
2088 // Don't allow safepoints in the branch shadow, that will
2089 // cause a number of difficulties
2090 if ( avail_pipeline->instructionCount() == 1 &&
2091 !avail_pipeline->hasMultipleBundles() &&
2092 !avail_pipeline->hasBranchDelay() &&
2093 Pipeline::instr_has_unit_size() &&
2094 d->size(_regalloc) == Pipeline::instr_unit_size() &&
2095 NodeFitsInBundle(d) &&
2096 !node_bundling(d)->used_in_delay()) {
2097
2098 if (d->is_Mach() && !d->is_MachSafePoint()) {
2099 // A node that fits in the delay slot was found, so we need to
2100 // set the appropriate bits in the bundle pipeline information so
2101 // that it correctly indicates resource usage. Later, when we
2102 // attempt to add this instruction to the bundle, we will skip
2103 // setting the resource usage.
2104 _unconditional_delay_slot = d;
2105 node_bundling(n)->set_use_unconditional_delay();
2106 node_bundling(d)->set_used_in_unconditional_delay();
2107 _bundle_use.add_usage(avail_pipeline->resourceUse());
2108 _current_latency[d->_idx] = _bundle_cycle_number;
2109 _next_node = d;
2110 ++_bundle_instr_count;
2111 #ifndef PRODUCT
2112 _unconditional_delays++;
2113 #endif
2114 break;
2115 }
2116 }
2117 }
2118 }
2119
2120 // No delay slot, add a nop to the usage
2121 if (!_unconditional_delay_slot) {
2122 // See if adding an instruction in the delay slot will overflow
2123 // the bundle.
2124 if (!NodeFitsInBundle(_nop)) {
2125 #ifndef PRODUCT
2126 if (_cfg->C->trace_opto_output())
2127 tty->print("# *** STEP(1 instruction for delay slot) ***\n");
2128 #endif
2129 step(1);
2130 }
2131
2132 _bundle_use.add_usage(_nop->pipeline()->resourceUse());
2133 _next_node = _nop;
2134 ++_bundle_instr_count;
2135 }
2136
2137 // See if the instruction in the delay slot requires a
2138 // step of the bundles
2139 if (!NodeFitsInBundle(n)) {
2140 #ifndef PRODUCT
2141 if (_cfg->C->trace_opto_output())
2142 tty->print("# *** STEP(branch won't fit) ***\n");
2143 #endif
2144 // Update the state information
2145 _bundle_instr_count = 0;
2146 _bundle_cycle_number += 1;
2147 _bundle_use.step(1);
2148 }
2149 }
2150
2151 // Get the number of instructions
2152 uint instruction_count = node_pipeline->instructionCount();
2153 if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
2154 instruction_count = 0;
2155
2156 // Compute the latency information
2157 uint delay = 0;
2158
2159 if (instruction_count > 0 || !node_pipeline->mayHaveNoCode()) {
2160 int relative_latency = _current_latency[n->_idx] - _bundle_cycle_number;
2161 if (relative_latency < 0)
2162 relative_latency = 0;
2163
2164 delay = _bundle_use.full_latency(relative_latency, node_usage);
2165
2166 // Does not fit in this bundle, start a new one
2167 if (delay > 0) {
2168 step(delay);
2169
2170 #ifndef PRODUCT
2171 if (_cfg->C->trace_opto_output())
2172 tty->print("# *** STEP(%d) ***\n", delay);
2173 #endif
2174 }
2175 }
2176
2177 // If this was placed in the delay slot, ignore it
2178 if (n != _unconditional_delay_slot) {
2179
2180 if (delay == 0) {
2181 if (node_pipeline->hasMultipleBundles()) {
2182 #ifndef PRODUCT
2183 if (_cfg->C->trace_opto_output())
2184 tty->print("# *** STEP(multiple instructions) ***\n");
2185 #endif
2186 step(1);
2187 }
2188
2189 else if (instruction_count + _bundle_instr_count > Pipeline::_max_instrs_per_cycle) {
2190 #ifndef PRODUCT
2191 if (_cfg->C->trace_opto_output())
2192 tty->print("# *** STEP(%d >= %d instructions) ***\n",
2193 instruction_count + _bundle_instr_count,
2194 Pipeline::_max_instrs_per_cycle);
2195 #endif
2196 step(1);
2197 }
2198 }
2199
2200 if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
2201 _bundle_instr_count++;
2202
2203 // Set the node's latency
2204 _current_latency[n->_idx] = _bundle_cycle_number;
2205
2206 // Now merge the functional unit information
2207 if (instruction_count > 0 || !node_pipeline->mayHaveNoCode())
2208 _bundle_use.add_usage(node_usage);
2209
2210 // Increment the number of instructions in this bundle
2211 _bundle_instr_count += instruction_count;
2212
2213 // Remember this node for later
2214 if (n->is_Mach())
2215 _next_node = n;
2216 }
2217
2218 // It's possible to have a BoxLock in the graph and in the _bbs mapping but
2219 // not in the bb->_nodes array. This happens for debug-info-only BoxLocks.
2220 // 'Schedule' them (basically ignore in the schedule) but do not insert them
2221 // into the block. All other scheduled nodes get put in the schedule here.
2222 int op = n->Opcode();
2223 if( (op == Op_Node && n->req() == 0) || // anti-dependence node OR
2224 (op != Op_Node && // Not an unused antidepedence node and
2225 // not an unallocated boxlock
2226 (OptoReg::is_valid(_regalloc->get_reg_first(n)) || op != Op_BoxLock)) ) {
2227
2228 // Push any trailing projections
2229 if( bb->get_node(bb->number_of_nodes()-1) != n ) {
2230 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2231 Node *foi = n->fast_out(i);
2232 if( foi->is_Proj() )
2233 _scheduled.push(foi);
2234 }
2235 }
2236
2237 // Put the instruction in the schedule list
2238 _scheduled.push(n);
2239 }
2240
2241 #ifndef PRODUCT
2242 if (_cfg->C->trace_opto_output())
2243 dump_available();
2244 #endif
2245
2246 // Walk all the definitions, decrementing use counts, and
2247 // if a definition has a 0 use count, place it in the available list.
2248 DecrementUseCounts(n,bb);
2249 }
2250
2251 // This method sets the use count within a basic block. We will ignore all
2252 // uses outside the current basic block. As we are doing a backwards walk,
2253 // any node we reach that has a use count of 0 may be scheduled. This also
2254 // avoids the problem of cyclic references from phi nodes, as long as phi
2255 // nodes are at the front of the basic block. This method also initializes
2256 // the available list to the set of instructions that have no uses within this
2257 // basic block.
2258 void Scheduling::ComputeUseCount(const Block *bb) {
2259 #ifndef PRODUCT
2260 if (_cfg->C->trace_opto_output())
2261 tty->print("# -> ComputeUseCount\n");
2262 #endif
2263
2264 // Clear the list of available and scheduled instructions, just in case
2265 _available.clear();
2266 _scheduled.clear();
2267
2268 // No delay slot specified
2269 _unconditional_delay_slot = NULL;
2270
2271 #ifdef ASSERT
2272 for( uint i=0; i < bb->number_of_nodes(); i++ )
2273 assert( _uses[bb->get_node(i)->_idx] == 0, "_use array not clean" );
2274 #endif
2275
2276 // Force the _uses count to never go to zero for unscheduable pieces
2277 // of the block
2278 for( uint k = 0; k < _bb_start; k++ )
2279 _uses[bb->get_node(k)->_idx] = 1;
2280 for( uint l = _bb_end; l < bb->number_of_nodes(); l++ )
2281 _uses[bb->get_node(l)->_idx] = 1;
2282
2283 // Iterate backwards over the instructions in the block. Don't count the
2284 // branch projections at end or the block header instructions.
2285 for( uint j = _bb_end-1; j >= _bb_start; j-- ) {
2286 Node *n = bb->get_node(j);
2287 if( n->is_Proj() ) continue; // Projections handled another way
2288
2289 // Account for all uses
2290 for ( uint k = 0; k < n->len(); k++ ) {
2291 Node *inp = n->in(k);
2292 if (!inp) continue;
2293 assert(inp != n, "no cycles allowed" );
2294 if (_cfg->get_block_for_node(inp) == bb) { // Block-local use?
2295 if (inp->is_Proj()) { // Skip through Proj's
2296 inp = inp->in(0);
2297 }
2298 ++_uses[inp->_idx]; // Count 1 block-local use
2299 }
2300 }
2301
2302 // If this instruction has a 0 use count, then it is available
2303 if (!_uses[n->_idx]) {
2304 _current_latency[n->_idx] = _bundle_cycle_number;
2305 AddNodeToAvailableList(n);
2306 }
2307
2308 #ifndef PRODUCT
2309 if (_cfg->C->trace_opto_output()) {
2310 tty->print("# uses: %3d: ", _uses[n->_idx]);
2311 n->dump();
2312 }
2313 #endif
2314 }
2315
2316 #ifndef PRODUCT
2317 if (_cfg->C->trace_opto_output())
2318 tty->print("# <- ComputeUseCount\n");
2319 #endif
2320 }
2321
2322 // This routine performs scheduling on each basic block in reverse order,
2323 // using instruction latencies and taking into account function unit
2324 // availability.
2325 void Scheduling::DoScheduling() {
2326 #ifndef PRODUCT
2327 if (_cfg->C->trace_opto_output())
2328 tty->print("# -> DoScheduling\n");
2329 #endif
2330
2331 Block *succ_bb = NULL;
2332 Block *bb;
2333
2334 // Walk over all the basic blocks in reverse order
2335 for (int i = _cfg->number_of_blocks() - 1; i >= 0; succ_bb = bb, i--) {
2336 bb = _cfg->get_block(i);
2337
2338 #ifndef PRODUCT
2339 if (_cfg->C->trace_opto_output()) {
2340 tty->print("# Schedule BB#%03d (initial)\n", i);
2341 for (uint j = 0; j < bb->number_of_nodes(); j++) {
2342 bb->get_node(j)->dump();
2343 }
2344 }
2345 #endif
2346
2347 // On the head node, skip processing
2348 if (bb == _cfg->get_root_block()) {
2349 continue;
2350 }
2351
2352 // Skip empty, connector blocks
2353 if (bb->is_connector())
2354 continue;
2355
2356 // If the following block is not the sole successor of
2357 // this one, then reset the pipeline information
2358 if (bb->_num_succs != 1 || bb->non_connector_successor(0) != succ_bb) {
2359 #ifndef PRODUCT
2360 if (_cfg->C->trace_opto_output()) {
2361 tty->print("*** bundle start of next BB, node %d, for %d instructions\n",
2362 _next_node->_idx, _bundle_instr_count);
2363 }
2364 #endif
2365 step_and_clear();
2366 }
2367
2368 // Leave untouched the starting instruction, any Phis, a CreateEx node
2369 // or Top. bb->get_node(_bb_start) is the first schedulable instruction.
2370 _bb_end = bb->number_of_nodes()-1;
2371 for( _bb_start=1; _bb_start <= _bb_end; _bb_start++ ) {
2372 Node *n = bb->get_node(_bb_start);
2373 // Things not matched, like Phinodes and ProjNodes don't get scheduled.
2374 // Also, MachIdealNodes do not get scheduled
2375 if( !n->is_Mach() ) continue; // Skip non-machine nodes
2376 MachNode *mach = n->as_Mach();
2377 int iop = mach->ideal_Opcode();
2378 if( iop == Op_CreateEx ) continue; // CreateEx is pinned
2379 if( iop == Op_Con ) continue; // Do not schedule Top
2380 if( iop == Op_Node && // Do not schedule PhiNodes, ProjNodes
2381 mach->pipeline() == MachNode::pipeline_class() &&
2382 !n->is_SpillCopy() && !n->is_MachMerge() ) // Breakpoints, Prolog, etc
2383 continue;
2384 break; // Funny loop structure to be sure...
2385 }
2386 // Compute last "interesting" instruction in block - last instruction we
2387 // might schedule. _bb_end points just after last schedulable inst. We
2388 // normally schedule conditional branches (despite them being forced last
2389 // in the block), because they have delay slots we can fill. Calls all
2390 // have their delay slots filled in the template expansions, so we don't
2391 // bother scheduling them.
2392 Node *last = bb->get_node(_bb_end);
2393 // Ignore trailing NOPs.
2394 while (_bb_end > 0 && last->is_Mach() &&
2395 last->as_Mach()->ideal_Opcode() == Op_Con) {
2396 last = bb->get_node(--_bb_end);
2397 }
2398 assert(!last->is_Mach() || last->as_Mach()->ideal_Opcode() != Op_Con, "");
2399 if( last->is_Catch() ||
2400 // Exclude unreachable path case when Halt node is in a separate block.
2401 (_bb_end > 1 && last->is_Mach() && last->as_Mach()->ideal_Opcode() == Op_Halt) ) {
2402 // There must be a prior call. Skip it.
2403 while( !bb->get_node(--_bb_end)->is_MachCall() ) {
2404 assert( bb->get_node(_bb_end)->is_MachProj(), "skipping projections after expected call" );
2405 }
2406 } else if( last->is_MachNullCheck() ) {
2407 // Backup so the last null-checked memory instruction is
2408 // outside the schedulable range. Skip over the nullcheck,
2409 // projection, and the memory nodes.
2410 Node *mem = last->in(1);
2411 do {
2412 _bb_end--;
2413 } while (mem != bb->get_node(_bb_end));
2414 } else {
2415 // Set _bb_end to point after last schedulable inst.
2416 _bb_end++;
2417 }
2418
2419 assert( _bb_start <= _bb_end, "inverted block ends" );
2420
2421 // Compute the register antidependencies for the basic block
2422 ComputeRegisterAntidependencies(bb);
2423 if (_cfg->C->failing()) return; // too many D-U pinch points
2424
2425 // Compute intra-bb latencies for the nodes
2426 ComputeLocalLatenciesForward(bb);
2427
2428 // Compute the usage within the block, and set the list of all nodes
2429 // in the block that have no uses within the block.
2430 ComputeUseCount(bb);
2431
2432 // Schedule the remaining instructions in the block
2433 while ( _available.size() > 0 ) {
2434 Node *n = ChooseNodeToBundle();
2435 guarantee(n != NULL, "no nodes available");
2436 AddNodeToBundle(n,bb);
2437 }
2438
2439 assert( _scheduled.size() == _bb_end - _bb_start, "wrong number of instructions" );
2440 #ifdef ASSERT
2441 for( uint l = _bb_start; l < _bb_end; l++ ) {
2442 Node *n = bb->get_node(l);
2443 uint m;
2444 for( m = 0; m < _bb_end-_bb_start; m++ )
2445 if( _scheduled[m] == n )
2446 break;
2447 assert( m < _bb_end-_bb_start, "instruction missing in schedule" );
2448 }
2449 #endif
2450
2451 // Now copy the instructions (in reverse order) back to the block
2452 for ( uint k = _bb_start; k < _bb_end; k++ )
2453 bb->map_node(_scheduled[_bb_end-k-1], k);
2454
2455 #ifndef PRODUCT
2456 if (_cfg->C->trace_opto_output()) {
2457 tty->print("# Schedule BB#%03d (final)\n", i);
2458 uint current = 0;
2459 for (uint j = 0; j < bb->number_of_nodes(); j++) {
2460 Node *n = bb->get_node(j);
2461 if( valid_bundle_info(n) ) {
2462 Bundle *bundle = node_bundling(n);
2463 if (bundle->instr_count() > 0 || bundle->flags() > 0) {
2464 tty->print("*** Bundle: ");
2465 bundle->dump();
2466 }
2467 n->dump();
2468 }
2469 }
2470 }
2471 #endif
2472 #ifdef ASSERT
2473 verify_good_schedule(bb,"after block local scheduling");
2474 #endif
2475 }
2476
2477 #ifndef PRODUCT
2478 if (_cfg->C->trace_opto_output())
2479 tty->print("# <- DoScheduling\n");
2480 #endif
2481
2482 // Record final node-bundling array location
2483 _regalloc->C->set_node_bundling_base(_node_bundling_base);
2484
2485 } // end DoScheduling
2486
2487 // Verify that no live-range used in the block is killed in the block by a
2488 // wrong DEF. This doesn't verify live-ranges that span blocks.
2489
2490 // Check for edge existence. Used to avoid adding redundant precedence edges.
2491 static bool edge_from_to( Node *from, Node *to ) {
2492 for( uint i=0; i<from->len(); i++ )
2493 if( from->in(i) == to )
2494 return true;
2495 return false;
2496 }
2497
2498 #ifdef ASSERT
2499 void Scheduling::verify_do_def( Node *n, OptoReg::Name def, const char *msg ) {
2500 // Check for bad kills
2501 if( OptoReg::is_valid(def) ) { // Ignore stores & control flow
2502 Node *prior_use = _reg_node[def];
2503 if( prior_use && !edge_from_to(prior_use,n) ) {
2504 tty->print("%s = ",OptoReg::as_VMReg(def)->name());
2505 n->dump();
2506 tty->print_cr("...");
2507 prior_use->dump();
2508 assert(edge_from_to(prior_use,n), "%s", msg);
2509 }
2510 _reg_node.map(def,NULL); // Kill live USEs
2511 }
2512 }
2513
2514 void Scheduling::verify_good_schedule( Block *b, const char *msg ) {
2515
2516 // Zap to something reasonable for the verify code
2517 _reg_node.clear();
2518
2519 // Walk over the block backwards. Check to make sure each DEF doesn't
2520 // kill a live value (other than the one it's supposed to). Add each
2521 // USE to the live set.
2522 for( uint i = b->number_of_nodes()-1; i >= _bb_start; i-- ) {
2523 Node *n = b->get_node(i);
2524 int n_op = n->Opcode();
2525 if( n_op == Op_MachProj && n->ideal_reg() == MachProjNode::fat_proj ) {
2526 // Fat-proj kills a slew of registers
2527 RegMask rm = n->out_RegMask();// Make local copy
2528 while( rm.is_NotEmpty() ) {
2529 OptoReg::Name kill = rm.find_first_elem();
2530 rm.Remove(kill);
2531 verify_do_def( n, kill, msg );
2532 }
2533 } else if( n_op != Op_Node ) { // Avoid brand new antidependence nodes
2534 // Get DEF'd registers the normal way
2535 verify_do_def( n, _regalloc->get_reg_first(n), msg );
2536 verify_do_def( n, _regalloc->get_reg_second(n), msg );
2537 }
2538
2539 // Now make all USEs live
2540 for( uint i=1; i<n->req(); i++ ) {
2541 Node *def = n->in(i);
2542 assert(def != 0, "input edge required");
2543 OptoReg::Name reg_lo = _regalloc->get_reg_first(def);
2544 OptoReg::Name reg_hi = _regalloc->get_reg_second(def);
2545 if( OptoReg::is_valid(reg_lo) ) {
2546 assert(!_reg_node[reg_lo] || edge_from_to(_reg_node[reg_lo],def), "%s", msg);
2547 _reg_node.map(reg_lo,n);
2548 }
2549 if( OptoReg::is_valid(reg_hi) ) {
2550 assert(!_reg_node[reg_hi] || edge_from_to(_reg_node[reg_hi],def), "%s", msg);
2551 _reg_node.map(reg_hi,n);
2552 }
2553 }
2554
2555 }
2556
2557 // Zap to something reasonable for the Antidependence code
2558 _reg_node.clear();
2559 }
2560 #endif
2561
2562 // Conditionally add precedence edges. Avoid putting edges on Projs.
2563 static void add_prec_edge_from_to( Node *from, Node *to ) {
2564 if( from->is_Proj() ) { // Put precedence edge on Proj's input
2565 assert( from->req() == 1 && (from->len() == 1 || from->in(1)==0), "no precedence edges on projections" );
2566 from = from->in(0);
2567 }
2568 if( from != to && // No cycles (for things like LD L0,[L0+4] )
2569 !edge_from_to( from, to ) ) // Avoid duplicate edge
2570 from->add_prec(to);
2571 }
2572
2573 void Scheduling::anti_do_def( Block *b, Node *def, OptoReg::Name def_reg, int is_def ) {
2574 if( !OptoReg::is_valid(def_reg) ) // Ignore stores & control flow
2575 return;
2576
2577 Node *pinch = _reg_node[def_reg]; // Get pinch point
2578 if ((pinch == NULL) || _cfg->get_block_for_node(pinch) != b || // No pinch-point yet?
2579 is_def ) { // Check for a true def (not a kill)
2580 _reg_node.map(def_reg,def); // Record def/kill as the optimistic pinch-point
2581 return;
2582 }
2583
2584 Node *kill = def; // Rename 'def' to more descriptive 'kill'
2585 debug_only( def = (Node*)((intptr_t)0xdeadbeef); )
2586
2587 // After some number of kills there _may_ be a later def
2588 Node *later_def = NULL;
2589
2590 // Finding a kill requires a real pinch-point.
2591 // Check for not already having a pinch-point.
2592 // Pinch points are Op_Node's.
2593 if( pinch->Opcode() != Op_Node ) { // Or later-def/kill as pinch-point?
2594 later_def = pinch; // Must be def/kill as optimistic pinch-point
2595 if ( _pinch_free_list.size() > 0) {
2596 pinch = _pinch_free_list.pop();
2597 } else {
2598 pinch = new Node(1); // Pinch point to-be
2599 }
2600 if (pinch->_idx >= _regalloc->node_regs_max_index()) {
2601 _cfg->C->record_method_not_compilable("too many D-U pinch points");
2602 return;
2603 }
2604 _cfg->map_node_to_block(pinch, b); // Pretend it's valid in this block (lazy init)
2605 _reg_node.map(def_reg,pinch); // Record pinch-point
2606 //_regalloc->set_bad(pinch->_idx); // Already initialized this way.
2607 if( later_def->outcnt() == 0 || later_def->ideal_reg() == MachProjNode::fat_proj ) { // Distinguish def from kill
2608 pinch->init_req(0, _cfg->C->top()); // set not NULL for the next call
2609 add_prec_edge_from_to(later_def,pinch); // Add edge from kill to pinch
2610 later_def = NULL; // and no later def
2611 }
2612 pinch->set_req(0,later_def); // Hook later def so we can find it
2613 } else { // Else have valid pinch point
2614 if( pinch->in(0) ) // If there is a later-def
2615 later_def = pinch->in(0); // Get it
2616 }
2617
2618 // Add output-dependence edge from later def to kill
2619 if( later_def ) // If there is some original def
2620 add_prec_edge_from_to(later_def,kill); // Add edge from def to kill
2621
2622 // See if current kill is also a use, and so is forced to be the pinch-point.
2623 if( pinch->Opcode() == Op_Node ) {
2624 Node *uses = kill->is_Proj() ? kill->in(0) : kill;
2625 for( uint i=1; i<uses->req(); i++ ) {
2626 if( _regalloc->get_reg_first(uses->in(i)) == def_reg ||
2627 _regalloc->get_reg_second(uses->in(i)) == def_reg ) {
2628 // Yes, found a use/kill pinch-point
2629 pinch->set_req(0,NULL); //
2630 pinch->replace_by(kill); // Move anti-dep edges up
2631 pinch = kill;
2632 _reg_node.map(def_reg,pinch);
2633 return;
2634 }
2635 }
2636 }
2637
2638 // Add edge from kill to pinch-point
2639 add_prec_edge_from_to(kill,pinch);
2640 }
2641
2642 void Scheduling::anti_do_use( Block *b, Node *use, OptoReg::Name use_reg ) {
2643 if( !OptoReg::is_valid(use_reg) ) // Ignore stores & control flow
2644 return;
2645 Node *pinch = _reg_node[use_reg]; // Get pinch point
2646 // Check for no later def_reg/kill in block
2647 if ((pinch != NULL) && _cfg->get_block_for_node(pinch) == b &&
2648 // Use has to be block-local as well
2649 _cfg->get_block_for_node(use) == b) {
2650 if( pinch->Opcode() == Op_Node && // Real pinch-point (not optimistic?)
2651 pinch->req() == 1 ) { // pinch not yet in block?
2652 pinch->del_req(0); // yank pointer to later-def, also set flag
2653 // Insert the pinch-point in the block just after the last use
2654 b->insert_node(pinch, b->find_node(use) + 1);
2655 _bb_end++; // Increase size scheduled region in block
2656 }
2657
2658 add_prec_edge_from_to(pinch,use);
2659 }
2660 }
2661
2662 // We insert antidependences between the reads and following write of
2663 // allocated registers to prevent illegal code motion. Hopefully, the
2664 // number of added references should be fairly small, especially as we
2665 // are only adding references within the current basic block.
2666 void Scheduling::ComputeRegisterAntidependencies(Block *b) {
2667
2668 #ifdef ASSERT
2669 verify_good_schedule(b,"before block local scheduling");
2670 #endif
2671
2672 // A valid schedule, for each register independently, is an endless cycle
2673 // of: a def, then some uses (connected to the def by true dependencies),
2674 // then some kills (defs with no uses), finally the cycle repeats with a new
2675 // def. The uses are allowed to float relative to each other, as are the
2676 // kills. No use is allowed to slide past a kill (or def). This requires
2677 // antidependencies between all uses of a single def and all kills that
2678 // follow, up to the next def. More edges are redundant, because later defs
2679 // & kills are already serialized with true or antidependencies. To keep
2680 // the edge count down, we add a 'pinch point' node if there's more than
2681 // one use or more than one kill/def.
2682
2683 // We add dependencies in one bottom-up pass.
2684
2685 // For each instruction we handle it's DEFs/KILLs, then it's USEs.
2686
2687 // For each DEF/KILL, we check to see if there's a prior DEF/KILL for this
2688 // register. If not, we record the DEF/KILL in _reg_node, the
2689 // register-to-def mapping. If there is a prior DEF/KILL, we insert a
2690 // "pinch point", a new Node that's in the graph but not in the block.
2691 // We put edges from the prior and current DEF/KILLs to the pinch point.
2692 // We put the pinch point in _reg_node. If there's already a pinch point
2693 // we merely add an edge from the current DEF/KILL to the pinch point.
2694
2695 // After doing the DEF/KILLs, we handle USEs. For each used register, we
2696 // put an edge from the pinch point to the USE.
2697
2698 // To be expedient, the _reg_node array is pre-allocated for the whole
2699 // compilation. _reg_node is lazily initialized; it either contains a NULL,
2700 // or a valid def/kill/pinch-point, or a leftover node from some prior
2701 // block. Leftover node from some prior block is treated like a NULL (no
2702 // prior def, so no anti-dependence needed). Valid def is distinguished by
2703 // it being in the current block.
2704 bool fat_proj_seen = false;
2705 uint last_safept = _bb_end-1;
2706 Node* end_node = (_bb_end-1 >= _bb_start) ? b->get_node(last_safept) : NULL;
2707 Node* last_safept_node = end_node;
2708 for( uint i = _bb_end-1; i >= _bb_start; i-- ) {
2709 Node *n = b->get_node(i);
2710 int is_def = n->outcnt(); // def if some uses prior to adding precedence edges
2711 if( n->is_MachProj() && n->ideal_reg() == MachProjNode::fat_proj ) {
2712 // Fat-proj kills a slew of registers
2713 // This can add edges to 'n' and obscure whether or not it was a def,
2714 // hence the is_def flag.
2715 fat_proj_seen = true;
2716 RegMask rm = n->out_RegMask();// Make local copy
2717 while( rm.is_NotEmpty() ) {
2718 OptoReg::Name kill = rm.find_first_elem();
2719 rm.Remove(kill);
2720 anti_do_def( b, n, kill, is_def );
2721 }
2722 } else {
2723 // Get DEF'd registers the normal way
2724 anti_do_def( b, n, _regalloc->get_reg_first(n), is_def );
2725 anti_do_def( b, n, _regalloc->get_reg_second(n), is_def );
2726 }
2727
2728 // Kill projections on a branch should appear to occur on the
2729 // branch, not afterwards, so grab the masks from the projections
2730 // and process them.
2731 if (n->is_MachBranch() || (n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_Jump)) {
2732 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2733 Node* use = n->fast_out(i);
2734 if (use->is_Proj()) {
2735 RegMask rm = use->out_RegMask();// Make local copy
2736 while( rm.is_NotEmpty() ) {
2737 OptoReg::Name kill = rm.find_first_elem();
2738 rm.Remove(kill);
2739 anti_do_def( b, n, kill, false );
2740 }
2741 }
2742 }
2743 }
2744
2745 // Check each register used by this instruction for a following DEF/KILL
2746 // that must occur afterward and requires an anti-dependence edge.
2747 for( uint j=0; j<n->req(); j++ ) {
2748 Node *def = n->in(j);
2749 if( def ) {
2750 assert( !def->is_MachProj() || def->ideal_reg() != MachProjNode::fat_proj, "" );
2751 anti_do_use( b, n, _regalloc->get_reg_first(def) );
2752 anti_do_use( b, n, _regalloc->get_reg_second(def) );
2753 }
2754 }
2755 // Do not allow defs of new derived values to float above GC
2756 // points unless the base is definitely available at the GC point.
2757
2758 Node *m = b->get_node(i);
2759
2760 // Add precedence edge from following safepoint to use of derived pointer
2761 if( last_safept_node != end_node &&
2762 m != last_safept_node) {
2763 for (uint k = 1; k < m->req(); k++) {
2764 const Type *t = m->in(k)->bottom_type();
2765 if( t->isa_oop_ptr() &&
2766 t->is_ptr()->offset() != 0 ) {
2767 last_safept_node->add_prec( m );
2768 break;
2769 }
2770 }
2771 }
2772
2773 if( n->jvms() ) { // Precedence edge from derived to safept
2774 // Check if last_safept_node was moved by pinch-point insertion in anti_do_use()
2775 if( b->get_node(last_safept) != last_safept_node ) {
2776 last_safept = b->find_node(last_safept_node);
2777 }
2778 for( uint j=last_safept; j > i; j-- ) {
2779 Node *mach = b->get_node(j);
2780 if( mach->is_Mach() && mach->as_Mach()->ideal_Opcode() == Op_AddP )
2781 mach->add_prec( n );
2782 }
2783 last_safept = i;
2784 last_safept_node = m;
2785 }
2786 }
2787
2788 if (fat_proj_seen) {
2789 // Garbage collect pinch nodes that were not consumed.
2790 // They are usually created by a fat kill MachProj for a call.
2791 garbage_collect_pinch_nodes();
2792 }
2793 }
2794
2795 // Garbage collect pinch nodes for reuse by other blocks.
2796 //
2797 // The block scheduler's insertion of anti-dependence
2798 // edges creates many pinch nodes when the block contains
2799 // 2 or more Calls. A pinch node is used to prevent a
2800 // combinatorial explosion of edges. If a set of kills for a
2801 // register is anti-dependent on a set of uses (or defs), rather
2802 // than adding an edge in the graph between each pair of kill
2803 // and use (or def), a pinch is inserted between them:
2804 //
2805 // use1 use2 use3
2806 // \ | /
2807 // \ | /
2808 // pinch
2809 // / | \
2810 // / | \
2811 // kill1 kill2 kill3
2812 //
2813 // One pinch node is created per register killed when
2814 // the second call is encountered during a backwards pass
2815 // over the block. Most of these pinch nodes are never
2816 // wired into the graph because the register is never
2817 // used or def'ed in the block.
2818 //
2819 void Scheduling::garbage_collect_pinch_nodes() {
2820 #ifndef PRODUCT
2821 if (_cfg->C->trace_opto_output()) tty->print("Reclaimed pinch nodes:");
2822 #endif
2823 int trace_cnt = 0;
2824 for (uint k = 0; k < _reg_node.Size(); k++) {
2825 Node* pinch = _reg_node[k];
2826 if ((pinch != NULL) && pinch->Opcode() == Op_Node &&
2827 // no predecence input edges
2828 (pinch->req() == pinch->len() || pinch->in(pinch->req()) == NULL) ) {
2829 cleanup_pinch(pinch);
2830 _pinch_free_list.push(pinch);
2831 _reg_node.map(k, NULL);
2832 #ifndef PRODUCT
2833 if (_cfg->C->trace_opto_output()) {
2834 trace_cnt++;
2835 if (trace_cnt > 40) {
2836 tty->print("\n");
2837 trace_cnt = 0;
2838 }
2839 tty->print(" %d", pinch->_idx);
2840 }
2841 #endif
2842 }
2843 }
2844 #ifndef PRODUCT
2845 if (_cfg->C->trace_opto_output()) tty->print("\n");
2846 #endif
2847 }
2848
2849 // Clean up a pinch node for reuse.
2850 void Scheduling::cleanup_pinch( Node *pinch ) {
2851 assert (pinch && pinch->Opcode() == Op_Node && pinch->req() == 1, "just checking");
2852
2853 for (DUIterator_Last imin, i = pinch->last_outs(imin); i >= imin; ) {
2854 Node* use = pinch->last_out(i);
2855 uint uses_found = 0;
2856 for (uint j = use->req(); j < use->len(); j++) {
2857 if (use->in(j) == pinch) {
2858 use->rm_prec(j);
2859 uses_found++;
2860 }
2861 }
2862 assert(uses_found > 0, "must be a precedence edge");
2863 i -= uses_found; // we deleted 1 or more copies of this edge
2864 }
2865 // May have a later_def entry
2866 pinch->set_req(0, NULL);
2867 }
2868
2869 #ifndef PRODUCT
2870
2871 void Scheduling::dump_available() const {
2872 tty->print("#Availist ");
2873 for (uint i = 0; i < _available.size(); i++)
2874 tty->print(" N%d/l%d", _available[i]->_idx,_current_latency[_available[i]->_idx]);
2875 tty->cr();
2876 }
2877
2878 // Print Scheduling Statistics
2879 void Scheduling::print_statistics() {
2880 // Print the size added by nops for bundling
2881 tty->print("Nops added %d bytes to total of %d bytes",
2882 _total_nop_size, _total_method_size);
2883 if (_total_method_size > 0)
2884 tty->print(", for %.2f%%",
2885 ((double)_total_nop_size) / ((double) _total_method_size) * 100.0);
2886 tty->print("\n");
2887
2888 // Print the number of branch shadows filled
2889 if (Pipeline::_branch_has_delay_slot) {
2890 tty->print("Of %d branches, %d had unconditional delay slots filled",
2891 _total_branches, _total_unconditional_delays);
2892 if (_total_branches > 0)
2893 tty->print(", for %.2f%%",
2894 ((double)_total_unconditional_delays) / ((double)_total_branches) * 100.0);
2895 tty->print("\n");
2896 }
2897
2898 uint total_instructions = 0, total_bundles = 0;
2899
2900 for (uint i = 1; i <= Pipeline::_max_instrs_per_cycle; i++) {
2901 uint bundle_count = _total_instructions_per_bundle[i];
2902 total_instructions += bundle_count * i;
2903 total_bundles += bundle_count;
2904 }
2905
2906 if (total_bundles > 0)
2907 tty->print("Average ILP (excluding nops) is %.2f\n",
2908 ((double)total_instructions) / ((double)total_bundles));
2909 }
2910 #endif