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