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