Mercurial > hg > truffle
comparison src/share/vm/c1/c1_LinearScan.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | dc7f315e41f7 |
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1 /* | |
2 * Copyright 2005-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 class DebugInfoCache; | |
26 class FpuStackAllocator; | |
27 class IRScopeDebugInfo; | |
28 class Interval; | |
29 class IntervalWalker; | |
30 class LIRGenerator; | |
31 class LinearScan; | |
32 class MoveResolver; | |
33 class Range; | |
34 | |
35 define_array(IntervalArray, Interval*) | |
36 define_stack(IntervalList, IntervalArray) | |
37 | |
38 define_array(IntervalsArray, IntervalList*) | |
39 define_stack(IntervalsList, IntervalsArray) | |
40 | |
41 define_array(OopMapArray, OopMap*) | |
42 define_stack(OopMapList, OopMapArray) | |
43 | |
44 define_array(ScopeValueArray, ScopeValue*) | |
45 | |
46 define_array(LIR_OpListArray, LIR_OpList*); | |
47 define_stack(LIR_OpListStack, LIR_OpListArray); | |
48 | |
49 | |
50 enum IntervalUseKind { | |
51 // priority of use kinds must be ascending | |
52 noUse = 0, | |
53 loopEndMarker = 1, | |
54 shouldHaveRegister = 2, | |
55 mustHaveRegister = 3, | |
56 | |
57 firstValidKind = 1, | |
58 lastValidKind = 3 | |
59 }; | |
60 define_array(UseKindArray, IntervalUseKind) | |
61 define_stack(UseKindStack, UseKindArray) | |
62 | |
63 | |
64 enum IntervalKind { | |
65 fixedKind = 0, // interval pre-colored by LIR_Generator | |
66 anyKind = 1, // no register/memory allocated by LIR_Generator | |
67 nofKinds, | |
68 firstKind = fixedKind | |
69 }; | |
70 | |
71 | |
72 // during linear scan an interval is in one of four states in | |
73 enum IntervalState { | |
74 unhandledState = 0, // unhandled state (not processed yet) | |
75 activeState = 1, // life and is in a physical register | |
76 inactiveState = 2, // in a life time hole and is in a physical register | |
77 handledState = 3, // spilled or not life again | |
78 invalidState = -1 | |
79 }; | |
80 | |
81 | |
82 enum IntervalSpillState { | |
83 noDefinitionFound, // starting state of calculation: no definition found yet | |
84 oneDefinitionFound, // one definition has already been found. | |
85 // Note: two consecutive definitions are treated as one (e.g. consecutive move and add because of two-operand LIR form) | |
86 // the position of this definition is stored in _definition_pos | |
87 oneMoveInserted, // one spill move has already been inserted. | |
88 storeAtDefinition, // the interval should be stored immediately after its definition because otherwise | |
89 // there would be multiple redundant stores | |
90 startInMemory, // the interval starts in memory (e.g. method parameter), so a store is never necessary | |
91 noOptimization // the interval has more then one definition (e.g. resulting from phi moves), so stores to memory are not optimized | |
92 }; | |
93 | |
94 | |
95 #define for_each_interval_kind(kind) \ | |
96 for (IntervalKind kind = firstKind; kind < nofKinds; kind = (IntervalKind)(kind + 1)) | |
97 | |
98 #define for_each_visitor_mode(mode) \ | |
99 for (LIR_OpVisitState::OprMode mode = LIR_OpVisitState::firstMode; mode < LIR_OpVisitState::numModes; mode = (LIR_OpVisitState::OprMode)(mode + 1)) | |
100 | |
101 | |
102 class LinearScan : public CompilationResourceObj { | |
103 // declare classes used by LinearScan as friends because they | |
104 // need a wide variety of functions declared here | |
105 // | |
106 // Only the small interface to the rest of the compiler is public | |
107 friend class Interval; | |
108 friend class IntervalWalker; | |
109 friend class LinearScanWalker; | |
110 friend class FpuStackAllocator; | |
111 friend class MoveResolver; | |
112 friend class LinearScanStatistic; | |
113 friend class LinearScanTimers; | |
114 friend class RegisterVerifier; | |
115 | |
116 public: | |
117 enum { | |
118 any_reg = -1, | |
119 nof_cpu_regs = pd_nof_cpu_regs_linearscan, | |
120 nof_fpu_regs = pd_nof_fpu_regs_linearscan, | |
121 nof_xmm_regs = pd_nof_xmm_regs_linearscan, | |
122 nof_regs = nof_cpu_regs + nof_fpu_regs + nof_xmm_regs | |
123 }; | |
124 | |
125 private: | |
126 Compilation* _compilation; | |
127 IR* _ir; | |
128 LIRGenerator* _gen; | |
129 FrameMap* _frame_map; | |
130 | |
131 BlockList _cached_blocks; // cached list with all blocks in linear-scan order (only correct if original list keeps unchanged) | |
132 int _num_virtual_regs; // number of virtual registers (without new registers introduced because of splitting intervals) | |
133 bool _has_fpu_registers; // true if this method uses any floating point registers (and so fpu stack allocation is necessary) | |
134 int _num_calls; // total number of calls in this method | |
135 int _max_spills; // number of stack slots used for intervals allocated to memory | |
136 int _unused_spill_slot; // unused spill slot for a single-word value because of alignment of a double-word value | |
137 | |
138 IntervalList _intervals; // mapping from register number to interval | |
139 IntervalList* _new_intervals_from_allocation; // list with all intervals created during allocation when an existing interval is split | |
140 IntervalArray* _sorted_intervals; // intervals sorted by Interval::from() | |
141 | |
142 LIR_OpArray _lir_ops; // mapping from LIR_Op id to LIR_Op node | |
143 BlockBeginArray _block_of_op; // mapping from LIR_Op id to the BlockBegin containing this instruction | |
144 BitMap _has_info; // bit set for each LIR_Op id that has a CodeEmitInfo | |
145 BitMap _has_call; // bit set for each LIR_Op id that destroys all caller save registers | |
146 BitMap2D _interval_in_loop; // bit set for each virtual register that is contained in each loop | |
147 | |
148 // cached debug info to prevent multiple creation of same object | |
149 // TODO: cached scope values for registers could be static | |
150 ScopeValueArray _scope_value_cache; | |
151 | |
152 static ConstantOopWriteValue _oop_null_scope_value; | |
153 static ConstantIntValue _int_m1_scope_value; | |
154 static ConstantIntValue _int_0_scope_value; | |
155 static ConstantIntValue _int_1_scope_value; | |
156 static ConstantIntValue _int_2_scope_value; | |
157 | |
158 // accessors | |
159 IR* ir() const { return _ir; } | |
160 Compilation* compilation() const { return _compilation; } | |
161 LIRGenerator* gen() const { return _gen; } | |
162 FrameMap* frame_map() const { return _frame_map; } | |
163 | |
164 // unified bailout support | |
165 void bailout(const char* msg) const { compilation()->bailout(msg); } | |
166 bool bailed_out() const { return compilation()->bailed_out(); } | |
167 | |
168 // access to block list (sorted in linear scan order) | |
169 int block_count() const { assert(_cached_blocks.length() == ir()->linear_scan_order()->length(), "invalid cached block list"); return _cached_blocks.length(); } | |
170 BlockBegin* block_at(int idx) const { assert(_cached_blocks.at(idx) == ir()->linear_scan_order()->at(idx), "invalid cached block list"); return _cached_blocks.at(idx); } | |
171 | |
172 int num_virtual_regs() const { return _num_virtual_regs; } | |
173 // size of live_in and live_out sets of BasicBlocks (BitMap needs rounded size for iteration) | |
174 int live_set_size() const { return round_to(_num_virtual_regs, BitsPerWord); } | |
175 bool has_fpu_registers() const { return _has_fpu_registers; } | |
176 int num_loops() const { return ir()->num_loops(); } | |
177 bool is_interval_in_loop(int interval, int loop) const { return _interval_in_loop.at(interval, loop); } | |
178 | |
179 // handling of fpu stack allocation (platform dependent, needed for debug information generation) | |
180 #ifdef IA32 | |
181 FpuStackAllocator* _fpu_stack_allocator; | |
182 bool use_fpu_stack_allocation() const { return UseSSE < 2 && has_fpu_registers(); } | |
183 #else | |
184 bool use_fpu_stack_allocation() const { return false; } | |
185 #endif | |
186 | |
187 | |
188 // access to interval list | |
189 int interval_count() const { return _intervals.length(); } | |
190 Interval* interval_at(int reg_num) const { return _intervals.at(reg_num); } | |
191 | |
192 IntervalList* new_intervals_from_allocation() const { return _new_intervals_from_allocation; } | |
193 | |
194 // access to LIR_Ops and Blocks indexed by op_id | |
195 int max_lir_op_id() const { assert(_lir_ops.length() > 0, "no operations"); return (_lir_ops.length() - 1) << 1; } | |
196 LIR_Op* lir_op_with_id(int op_id) const { assert(op_id >= 0 && op_id <= max_lir_op_id() && op_id % 2 == 0, "op_id out of range or not even"); return _lir_ops.at(op_id >> 1); } | |
197 BlockBegin* block_of_op_with_id(int op_id) const { assert(_block_of_op.length() > 0 && op_id >= 0 && op_id <= max_lir_op_id() + 1, "op_id out of range"); return _block_of_op.at(op_id >> 1); } | |
198 | |
199 bool is_block_begin(int op_id) { return op_id == 0 || block_of_op_with_id(op_id) != block_of_op_with_id(op_id - 1); } | |
200 bool covers_block_begin(int op_id_1, int op_id_2) { return block_of_op_with_id(op_id_1) != block_of_op_with_id(op_id_2); } | |
201 | |
202 bool has_call(int op_id) { assert(op_id % 2 == 0, "must be even"); return _has_call.at(op_id >> 1); } | |
203 bool has_info(int op_id) { assert(op_id % 2 == 0, "must be even"); return _has_info.at(op_id >> 1); } | |
204 | |
205 | |
206 // functions for converting LIR-Operands to register numbers | |
207 static bool is_valid_reg_num(int reg_num) { return reg_num >= 0; } | |
208 static int reg_num(LIR_Opr opr); | |
209 static int reg_numHi(LIR_Opr opr); | |
210 | |
211 // functions for classification of intervals | |
212 static bool is_precolored_interval(const Interval* i); | |
213 static bool is_virtual_interval(const Interval* i); | |
214 | |
215 static bool is_precolored_cpu_interval(const Interval* i); | |
216 static bool is_virtual_cpu_interval(const Interval* i); | |
217 static bool is_precolored_fpu_interval(const Interval* i); | |
218 static bool is_virtual_fpu_interval(const Interval* i); | |
219 | |
220 static bool is_in_fpu_register(const Interval* i); | |
221 static bool is_oop_interval(const Interval* i); | |
222 | |
223 | |
224 // General helper functions | |
225 int allocate_spill_slot(bool double_word); | |
226 void assign_spill_slot(Interval* it); | |
227 void propagate_spill_slots(); | |
228 | |
229 Interval* create_interval(int reg_num); | |
230 void append_interval(Interval* it); | |
231 void copy_register_flags(Interval* from, Interval* to); | |
232 | |
233 // platform dependent functions | |
234 static bool is_processed_reg_num(int reg_num); | |
235 static int num_physical_regs(BasicType type); | |
236 static bool requires_adjacent_regs(BasicType type); | |
237 static bool is_caller_save(int assigned_reg); | |
238 | |
239 // spill move optimization: eliminate moves from register to stack if | |
240 // stack slot is known to be correct | |
241 void change_spill_definition_pos(Interval* interval, int def_pos); | |
242 void change_spill_state(Interval* interval, int spill_pos); | |
243 static bool must_store_at_definition(const Interval* i); | |
244 void eliminate_spill_moves(); | |
245 | |
246 // Phase 1: number all instructions in all blocks | |
247 void number_instructions(); | |
248 | |
249 // Phase 2: compute local live sets separately for each block | |
250 // (sets live_gen and live_kill for each block) | |
251 // | |
252 // helper methods used by compute_local_live_sets() | |
253 void set_live_gen_kill(Value value, LIR_Op* op, BitMap& live_gen, BitMap& live_kill); | |
254 | |
255 void compute_local_live_sets(); | |
256 | |
257 // Phase 3: perform a backward dataflow analysis to compute global live sets | |
258 // (sets live_in and live_out for each block) | |
259 void compute_global_live_sets(); | |
260 | |
261 | |
262 // Phase 4: build intervals | |
263 // (fills the list _intervals) | |
264 // | |
265 // helper methods used by build_intervals() | |
266 void add_use (Value value, int from, int to, IntervalUseKind use_kind); | |
267 | |
268 void add_def (LIR_Opr opr, int def_pos, IntervalUseKind use_kind); | |
269 void add_use (LIR_Opr opr, int from, int to, IntervalUseKind use_kind); | |
270 void add_temp(LIR_Opr opr, int temp_pos, IntervalUseKind use_kind); | |
271 | |
272 void add_def (int reg_num, int def_pos, IntervalUseKind use_kind, BasicType type); | |
273 void add_use (int reg_num, int from, int to, IntervalUseKind use_kind, BasicType type); | |
274 void add_temp(int reg_num, int temp_pos, IntervalUseKind use_kind, BasicType type); | |
275 | |
276 // Add platform dependent kills for particular LIR ops. Can be used | |
277 // to add platform dependent behaviour for some operations. | |
278 void pd_add_temps(LIR_Op* op); | |
279 | |
280 IntervalUseKind use_kind_of_output_operand(LIR_Op* op, LIR_Opr opr); | |
281 IntervalUseKind use_kind_of_input_operand(LIR_Op* op, LIR_Opr opr); | |
282 void handle_method_arguments(LIR_Op* op); | |
283 void handle_doubleword_moves(LIR_Op* op); | |
284 void add_register_hints(LIR_Op* op); | |
285 | |
286 void build_intervals(); | |
287 | |
288 | |
289 // Phase 5: actual register allocation | |
290 // (Uses LinearScanWalker) | |
291 // | |
292 // helper functions for building a sorted list of intervals | |
293 NOT_PRODUCT(bool is_sorted(IntervalArray* intervals);) | |
294 static int interval_cmp(Interval** a, Interval** b); | |
295 void add_to_list(Interval** first, Interval** prev, Interval* interval); | |
296 void create_unhandled_lists(Interval** list1, Interval** list2, bool (is_list1)(const Interval* i), bool (is_list2)(const Interval* i)); | |
297 | |
298 void sort_intervals_before_allocation(); | |
299 void sort_intervals_after_allocation(); | |
300 void allocate_registers(); | |
301 | |
302 | |
303 // Phase 6: resolve data flow | |
304 // (insert moves at edges between blocks if intervals have been split) | |
305 // | |
306 // helper functions for resolve_data_flow() | |
307 Interval* split_child_at_op_id(Interval* interval, int op_id, LIR_OpVisitState::OprMode mode); | |
308 Interval* interval_at_block_begin(BlockBegin* block, int reg_num); | |
309 Interval* interval_at_block_end(BlockBegin* block, int reg_num); | |
310 Interval* interval_at_op_id(int reg_num, int op_id); | |
311 void resolve_collect_mappings(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver); | |
312 void resolve_find_insert_pos(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver); | |
313 void resolve_data_flow(); | |
314 | |
315 void resolve_exception_entry(BlockBegin* block, int reg_num, MoveResolver &move_resolver); | |
316 void resolve_exception_entry(BlockBegin* block, MoveResolver &move_resolver); | |
317 void resolve_exception_edge(XHandler* handler, int throwing_op_id, int reg_num, Phi* phi, MoveResolver &move_resolver); | |
318 void resolve_exception_edge(XHandler* handler, int throwing_op_id, MoveResolver &move_resolver); | |
319 void resolve_exception_handlers(); | |
320 | |
321 // Phase 7: assign register numbers back to LIR | |
322 // (includes computation of debug information and oop maps) | |
323 // | |
324 // helper functions for assign_reg_num() | |
325 VMReg vm_reg_for_interval(Interval* interval); | |
326 VMReg vm_reg_for_operand(LIR_Opr opr); | |
327 | |
328 static LIR_Opr operand_for_interval(Interval* interval); | |
329 static LIR_Opr calc_operand_for_interval(const Interval* interval); | |
330 LIR_Opr canonical_spill_opr(Interval* interval); | |
331 | |
332 LIR_Opr color_lir_opr(LIR_Opr opr, int id, LIR_OpVisitState::OprMode); | |
333 | |
334 // methods used for oop map computation | |
335 IntervalWalker* init_compute_oop_maps(); | |
336 OopMap* compute_oop_map(IntervalWalker* iw, LIR_Op* op, CodeEmitInfo* info, bool is_call_site); | |
337 void compute_oop_map(IntervalWalker* iw, const LIR_OpVisitState &visitor, LIR_Op* op); | |
338 | |
339 // methods used for debug information computation | |
340 void init_compute_debug_info(); | |
341 | |
342 MonitorValue* location_for_monitor_index(int monitor_index); | |
343 LocationValue* location_for_name(int name, Location::Type loc_type); | |
344 | |
345 int append_scope_value_for_constant(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values); | |
346 int append_scope_value_for_operand(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values); | |
347 int append_scope_value(int op_id, Value value, GrowableArray<ScopeValue*>* scope_values); | |
348 | |
349 IRScopeDebugInfo* compute_debug_info_for_scope(int op_id, IRScope* cur_scope, ValueStack* cur_state, ValueStack* innermost_state, int cur_bci, int stack_end, int locks_end); | |
350 void compute_debug_info(CodeEmitInfo* info, int op_id); | |
351 | |
352 void assign_reg_num(LIR_OpList* instructions, IntervalWalker* iw); | |
353 void assign_reg_num(); | |
354 | |
355 | |
356 // Phase 8: fpu stack allocation | |
357 // (Used only on x86 when fpu operands are present) | |
358 void allocate_fpu_stack(); | |
359 | |
360 | |
361 // helper functions for printing state | |
362 #ifndef PRODUCT | |
363 static void print_bitmap(BitMap& bitmap); | |
364 void print_intervals(const char* label); | |
365 void print_lir(int level, const char* label, bool hir_valid = true); | |
366 #endif | |
367 | |
368 #ifdef ASSERT | |
369 // verification functions for allocation | |
370 // (check that all intervals have a correct register and that no registers are overwritten) | |
371 void verify(); | |
372 void verify_intervals(); | |
373 void verify_no_oops_in_fixed_intervals(); | |
374 void verify_constants(); | |
375 void verify_registers(); | |
376 #endif | |
377 | |
378 public: | |
379 // creation | |
380 LinearScan(IR* ir, LIRGenerator* gen, FrameMap* frame_map); | |
381 | |
382 // main entry function: perform linear scan register allocation | |
383 void do_linear_scan(); | |
384 | |
385 // accessors used by Compilation | |
386 int max_spills() const { return _max_spills; } | |
387 int num_calls() const { assert(_num_calls >= 0, "not set"); return _num_calls; } | |
388 | |
389 // entry functions for printing | |
390 #ifndef PRODUCT | |
391 static void print_statistics(); | |
392 static void print_timers(double total); | |
393 #endif | |
394 }; | |
395 | |
396 | |
397 // Helper class for ordering moves that are inserted at the same position in the LIR | |
398 // When moves between registers are inserted, it is important that the moves are | |
399 // ordered such that no register is overwritten. So moves from register to stack | |
400 // are processed prior to moves from stack to register. When moves have circular | |
401 // dependencies, a temporary stack slot is used to break the circle. | |
402 // The same logic is used in the LinearScanWalker and in LinearScan during resolve_data_flow | |
403 // and therefore factored out in a separate class | |
404 class MoveResolver: public StackObj { | |
405 private: | |
406 LinearScan* _allocator; | |
407 | |
408 LIR_List* _insert_list; | |
409 int _insert_idx; | |
410 LIR_InsertionBuffer _insertion_buffer; // buffer where moves are inserted | |
411 | |
412 IntervalList _mapping_from; | |
413 LIR_OprList _mapping_from_opr; | |
414 IntervalList _mapping_to; | |
415 bool _multiple_reads_allowed; | |
416 int _register_blocked[LinearScan::nof_regs]; | |
417 | |
418 int register_blocked(int reg) { assert(reg >= 0 && reg < LinearScan::nof_regs, "out of bounds"); return _register_blocked[reg]; } | |
419 void set_register_blocked(int reg, int direction) { assert(reg >= 0 && reg < LinearScan::nof_regs, "out of bounds"); assert(direction == 1 || direction == -1, "out of bounds"); _register_blocked[reg] += direction; } | |
420 | |
421 void block_registers(Interval* it); | |
422 void unblock_registers(Interval* it); | |
423 bool save_to_process_move(Interval* from, Interval* to); | |
424 | |
425 void create_insertion_buffer(LIR_List* list); | |
426 void append_insertion_buffer(); | |
427 void insert_move(Interval* from_interval, Interval* to_interval); | |
428 void insert_move(LIR_Opr from_opr, Interval* to_interval); | |
429 | |
430 DEBUG_ONLY(void verify_before_resolve();) | |
431 void resolve_mappings(); | |
432 public: | |
433 MoveResolver(LinearScan* allocator); | |
434 | |
435 DEBUG_ONLY(void check_empty();) | |
436 void set_multiple_reads_allowed() { _multiple_reads_allowed = true; } | |
437 void set_insert_position(LIR_List* insert_list, int insert_idx); | |
438 void move_insert_position(LIR_List* insert_list, int insert_idx); | |
439 void add_mapping(Interval* from, Interval* to); | |
440 void add_mapping(LIR_Opr from, Interval* to); | |
441 void resolve_and_append_moves(); | |
442 | |
443 LinearScan* allocator() { return _allocator; } | |
444 bool has_mappings() { return _mapping_from.length() > 0; } | |
445 }; | |
446 | |
447 | |
448 class Range : public CompilationResourceObj { | |
449 friend class Interval; | |
450 | |
451 private: | |
452 static Range* _end; // sentinel (from == to == max_jint) | |
453 | |
454 int _from; // from (inclusive) | |
455 int _to; // to (exclusive) | |
456 Range* _next; // linear list of Ranges | |
457 | |
458 // used only by class Interval, so hide them | |
459 bool intersects(Range* r) const { return intersects_at(r) != -1; } | |
460 int intersects_at(Range* r) const; | |
461 | |
462 public: | |
463 Range(int from, int to, Range* next); | |
464 | |
465 static void initialize(); | |
466 static Range* end() { return _end; } | |
467 | |
468 int from() const { return _from; } | |
469 int to() const { return _to; } | |
470 Range* next() const { return _next; } | |
471 void set_from(int from) { _from = from; } | |
472 void set_to(int to) { _to = to; } | |
473 void set_next(Range* next) { _next = next; } | |
474 | |
475 // for testing | |
476 void print(outputStream* out = tty) const PRODUCT_RETURN; | |
477 }; | |
478 | |
479 | |
480 // Interval is an ordered list of disjoint ranges. | |
481 | |
482 // For pre-colored double word LIR_Oprs, one interval is created for | |
483 // the low word register and one is created for the hi word register. | |
484 // On Intel for FPU double registers only one interval is created. At | |
485 // all times assigned_reg contains the reg. number of the physical | |
486 // register. | |
487 | |
488 // For LIR_Opr in virtual registers a single interval can represent | |
489 // single and double word values. When a physical register is | |
490 // assigned to the interval, assigned_reg contains the | |
491 // phys. reg. number and for double word values assigned_regHi the | |
492 // phys. reg. number of the hi word if there is any. For spilled | |
493 // intervals assigned_reg contains the stack index. assigned_regHi is | |
494 // always -1. | |
495 | |
496 class Interval : public CompilationResourceObj { | |
497 private: | |
498 static Interval* _end; // sentinel (interval with only range Range::end()) | |
499 | |
500 int _reg_num; | |
501 BasicType _type; // valid only for virtual registers | |
502 Range* _first; // sorted list of Ranges | |
503 intStack _use_pos_and_kinds; // sorted list of use-positions and their according use-kinds | |
504 | |
505 Range* _current; // interval iteration: the current Range | |
506 Interval* _next; // interval iteration: sorted list of Intervals (ends with sentinel) | |
507 IntervalState _state; // interval iteration: to which set belongs this interval | |
508 | |
509 | |
510 int _assigned_reg; | |
511 int _assigned_regHi; | |
512 | |
513 int _cached_to; // cached value: to of last range (-1: not cached) | |
514 LIR_Opr _cached_opr; | |
515 VMReg _cached_vm_reg; | |
516 | |
517 Interval* _split_parent; // the original interval where this interval is derived from | |
518 IntervalList _split_children; // list of all intervals that are split off from this interval (only available for split parents) | |
519 Interval* _current_split_child; // the current split child that has been active or inactive last (always stored in split parents) | |
520 | |
521 int _canonical_spill_slot; // the stack slot where all split parts of this interval are spilled to (always stored in split parents) | |
522 bool _insert_move_when_activated; // true if move is inserted between _current_split_child and this interval when interval gets active the first time | |
523 IntervalSpillState _spill_state; // for spill move optimization | |
524 int _spill_definition_pos; // position where the interval is defined (if defined only once) | |
525 Interval* _register_hint; // this interval should be in the same register as the hint interval | |
526 | |
527 int calc_to(); | |
528 Interval* new_split_child(); | |
529 public: | |
530 Interval(int reg_num); | |
531 | |
532 static void initialize(); | |
533 static Interval* end() { return _end; } | |
534 | |
535 // accessors | |
536 int reg_num() const { return _reg_num; } | |
537 void set_reg_num(int r) { assert(_reg_num == -1, "cannot change reg_num"); _reg_num = r; } | |
538 BasicType type() const { assert(_reg_num == -1 || _reg_num >= LIR_OprDesc::vreg_base, "cannot access type for fixed interval"); return _type; } | |
539 void set_type(BasicType type) { assert(_reg_num < LIR_OprDesc::vreg_base || _type == T_ILLEGAL || _type == type, "overwriting existing type"); _type = type; } | |
540 | |
541 Range* first() const { return _first; } | |
542 int from() const { return _first->from(); } | |
543 int to() { if (_cached_to == -1) _cached_to = calc_to(); assert(_cached_to == calc_to(), "invalid cached value"); return _cached_to; } | |
544 int num_use_positions() const { return _use_pos_and_kinds.length() / 2; } | |
545 | |
546 Interval* next() const { return _next; } | |
547 Interval** next_addr() { return &_next; } | |
548 void set_next(Interval* next) { _next = next; } | |
549 | |
550 int assigned_reg() const { return _assigned_reg; } | |
551 int assigned_regHi() const { return _assigned_regHi; } | |
552 void assign_reg(int reg) { _assigned_reg = reg; _assigned_regHi = LinearScan::any_reg; } | |
553 void assign_reg(int reg,int regHi) { _assigned_reg = reg; _assigned_regHi = regHi; } | |
554 | |
555 Interval* register_hint(bool search_split_child = true) const; // calculation needed | |
556 void set_register_hint(Interval* i) { _register_hint = i; } | |
557 | |
558 int state() const { return _state; } | |
559 void set_state(IntervalState s) { _state = s; } | |
560 | |
561 // access to split parent and split children | |
562 bool is_split_parent() const { return _split_parent == this; } | |
563 bool is_split_child() const { return _split_parent != this; } | |
564 Interval* split_parent() const { assert(_split_parent->is_split_parent(), "must be"); return _split_parent; } | |
565 Interval* split_child_at_op_id(int op_id, LIR_OpVisitState::OprMode mode); | |
566 Interval* split_child_before_op_id(int op_id); | |
567 bool split_child_covers(int op_id, LIR_OpVisitState::OprMode mode); | |
568 DEBUG_ONLY(void check_split_children();) | |
569 | |
570 // information stored in split parent, but available for all children | |
571 int canonical_spill_slot() const { return split_parent()->_canonical_spill_slot; } | |
572 void set_canonical_spill_slot(int slot) { assert(split_parent()->_canonical_spill_slot == -1, "overwriting existing value"); split_parent()->_canonical_spill_slot = slot; } | |
573 Interval* current_split_child() const { return split_parent()->_current_split_child; } | |
574 void make_current_split_child() { split_parent()->_current_split_child = this; } | |
575 | |
576 bool insert_move_when_activated() const { return _insert_move_when_activated; } | |
577 void set_insert_move_when_activated(bool b) { _insert_move_when_activated = b; } | |
578 | |
579 // for spill optimization | |
580 IntervalSpillState spill_state() const { return split_parent()->_spill_state; } | |
581 int spill_definition_pos() const { return split_parent()->_spill_definition_pos; } | |
582 void set_spill_state(IntervalSpillState state) { assert(state >= spill_state(), "state cannot decrease"); split_parent()->_spill_state = state; } | |
583 void set_spill_definition_pos(int pos) { assert(spill_definition_pos() == -1, "cannot set the position twice"); split_parent()->_spill_definition_pos = pos; } | |
584 // returns true if this interval has a shadow copy on the stack that is always correct | |
585 bool always_in_memory() const { return split_parent()->_spill_state == storeAtDefinition || split_parent()->_spill_state == startInMemory; } | |
586 | |
587 // caching of values that take time to compute and are used multiple times | |
588 LIR_Opr cached_opr() const { return _cached_opr; } | |
589 VMReg cached_vm_reg() const { return _cached_vm_reg; } | |
590 void set_cached_opr(LIR_Opr opr) { _cached_opr = opr; } | |
591 void set_cached_vm_reg(VMReg reg) { _cached_vm_reg = reg; } | |
592 | |
593 // access to use positions | |
594 int first_usage(IntervalUseKind min_use_kind) const; // id of the first operation requiring this interval in a register | |
595 int next_usage(IntervalUseKind min_use_kind, int from) const; // id of next usage seen from the given position | |
596 int next_usage_exact(IntervalUseKind exact_use_kind, int from) const; | |
597 int previous_usage(IntervalUseKind min_use_kind, int from) const; | |
598 | |
599 // manipulating intervals | |
600 void add_use_pos(int pos, IntervalUseKind use_kind); | |
601 void add_range(int from, int to); | |
602 Interval* split(int split_pos); | |
603 Interval* split_from_start(int split_pos); | |
604 void remove_first_use_pos() { _use_pos_and_kinds.truncate(_use_pos_and_kinds.length() - 2); } | |
605 | |
606 // test intersection | |
607 bool covers(int op_id, LIR_OpVisitState::OprMode mode) const; | |
608 bool has_hole_between(int from, int to); | |
609 bool intersects(Interval* i) const { return _first->intersects(i->_first); } | |
610 int intersects_at(Interval* i) const { return _first->intersects_at(i->_first); } | |
611 | |
612 // range iteration | |
613 void rewind_range() { _current = _first; } | |
614 void next_range() { assert(this != _end, "not allowed on sentinel"); _current = _current->next(); } | |
615 int current_from() const { return _current->from(); } | |
616 int current_to() const { return _current->to(); } | |
617 bool current_at_end() const { return _current == Range::end(); } | |
618 bool current_intersects(Interval* it) { return _current->intersects(it->_current); }; | |
619 int current_intersects_at(Interval* it) { return _current->intersects_at(it->_current); }; | |
620 | |
621 // printing | |
622 void print(outputStream* out = tty) const PRODUCT_RETURN; | |
623 }; | |
624 | |
625 | |
626 class IntervalWalker : public CompilationResourceObj { | |
627 protected: | |
628 Compilation* _compilation; | |
629 LinearScan* _allocator; | |
630 | |
631 Interval* _unhandled_first[nofKinds]; // sorted list of intervals, not life before the current position | |
632 Interval* _active_first [nofKinds]; // sorted list of intervals, life at the current position | |
633 Interval* _inactive_first [nofKinds]; // sorted list of intervals, intervals in a life time hole at the current position | |
634 | |
635 Interval* _current; // the current interval coming from unhandled list | |
636 int _current_position; // the current position (intercept point through the intervals) | |
637 IntervalKind _current_kind; // and whether it is fixed_kind or any_kind. | |
638 | |
639 | |
640 Compilation* compilation() const { return _compilation; } | |
641 LinearScan* allocator() const { return _allocator; } | |
642 | |
643 // unified bailout support | |
644 void bailout(const char* msg) const { compilation()->bailout(msg); } | |
645 bool bailed_out() const { return compilation()->bailed_out(); } | |
646 | |
647 void check_bounds(IntervalKind kind) { assert(kind >= fixedKind && kind <= anyKind, "invalid interval_kind"); } | |
648 | |
649 Interval** unhandled_first_addr(IntervalKind kind) { check_bounds(kind); return &_unhandled_first[kind]; } | |
650 Interval** active_first_addr(IntervalKind kind) { check_bounds(kind); return &_active_first[kind]; } | |
651 Interval** inactive_first_addr(IntervalKind kind) { check_bounds(kind); return &_inactive_first[kind]; } | |
652 | |
653 void append_unsorted(Interval** first, Interval* interval); | |
654 void append_sorted(Interval** first, Interval* interval); | |
655 void append_to_unhandled(Interval** list, Interval* interval); | |
656 | |
657 bool remove_from_list(Interval** list, Interval* i); | |
658 void remove_from_list(Interval* i); | |
659 | |
660 void next_interval(); | |
661 Interval* current() const { return _current; } | |
662 IntervalKind current_kind() const { return _current_kind; } | |
663 | |
664 void walk_to(IntervalState state, int from); | |
665 | |
666 // activate_current() is called when an unhandled interval becomes active (in current(), current_kind()). | |
667 // Return false if current() should not be moved the the active interval list. | |
668 // It is safe to append current to any interval list but the unhandled list. | |
669 virtual bool activate_current() { return true; } | |
670 | |
671 // interval_moved() is called whenever an interval moves from one interval list to another. | |
672 // In the implementation of this method it is prohibited to move the interval to any list. | |
673 virtual void interval_moved(Interval* interval, IntervalKind kind, IntervalState from, IntervalState to); | |
674 | |
675 public: | |
676 IntervalWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first); | |
677 | |
678 Interval* unhandled_first(IntervalKind kind) { check_bounds(kind); return _unhandled_first[kind]; } | |
679 Interval* active_first(IntervalKind kind) { check_bounds(kind); return _active_first[kind]; } | |
680 Interval* inactive_first(IntervalKind kind) { check_bounds(kind); return _inactive_first[kind]; } | |
681 | |
682 // active contains the intervals that are live after the lir_op | |
683 void walk_to(int lir_op_id); | |
684 // active contains the intervals that are live before the lir_op | |
685 void walk_before(int lir_op_id) { walk_to(lir_op_id-1); } | |
686 // walk through all intervals | |
687 void walk() { walk_to(max_jint); } | |
688 | |
689 int current_position() { return _current_position; } | |
690 }; | |
691 | |
692 | |
693 // The actual linear scan register allocator | |
694 class LinearScanWalker : public IntervalWalker { | |
695 enum { | |
696 any_reg = LinearScan::any_reg | |
697 }; | |
698 | |
699 private: | |
700 int _first_reg; // the reg. number of the first phys. register | |
701 int _last_reg; // the reg. nmber of the last phys. register | |
702 int _num_phys_regs; // required by current interval | |
703 bool _adjacent_regs; // have lo/hi words of phys. regs be adjacent | |
704 | |
705 int _use_pos[LinearScan::nof_regs]; | |
706 int _block_pos[LinearScan::nof_regs]; | |
707 IntervalList* _spill_intervals[LinearScan::nof_regs]; | |
708 | |
709 MoveResolver _move_resolver; // for ordering spill moves | |
710 | |
711 // accessors mapped to same functions in class LinearScan | |
712 int block_count() const { return allocator()->block_count(); } | |
713 BlockBegin* block_at(int idx) const { return allocator()->block_at(idx); } | |
714 BlockBegin* block_of_op_with_id(int op_id) const { return allocator()->block_of_op_with_id(op_id); } | |
715 | |
716 void init_use_lists(bool only_process_use_pos); | |
717 void exclude_from_use(int reg); | |
718 void exclude_from_use(Interval* i); | |
719 void set_use_pos(int reg, Interval* i, int use_pos, bool only_process_use_pos); | |
720 void set_use_pos(Interval* i, int use_pos, bool only_process_use_pos); | |
721 void set_block_pos(int reg, Interval* i, int block_pos); | |
722 void set_block_pos(Interval* i, int block_pos); | |
723 | |
724 void free_exclude_active_fixed(); | |
725 void free_exclude_active_any(); | |
726 void free_collect_inactive_fixed(Interval* cur); | |
727 void free_collect_inactive_any(Interval* cur); | |
728 void free_collect_unhandled(IntervalKind kind, Interval* cur); | |
729 void spill_exclude_active_fixed(); | |
730 void spill_block_unhandled_fixed(Interval* cur); | |
731 void spill_block_inactive_fixed(Interval* cur); | |
732 void spill_collect_active_any(); | |
733 void spill_collect_inactive_any(Interval* cur); | |
734 | |
735 void insert_move(int op_id, Interval* src_it, Interval* dst_it); | |
736 int find_optimal_split_pos(BlockBegin* min_block, BlockBegin* max_block, int max_split_pos); | |
737 int find_optimal_split_pos(Interval* it, int min_split_pos, int max_split_pos, bool do_loop_optimization); | |
738 void split_before_usage(Interval* it, int min_split_pos, int max_split_pos); | |
739 void split_for_spilling(Interval* it); | |
740 void split_stack_interval(Interval* it); | |
741 void split_when_partial_register_available(Interval* it, int register_available_until); | |
742 void split_and_spill_interval(Interval* it); | |
743 | |
744 int find_free_reg(int reg_needed_until, int interval_to, int hint_reg, int ignore_reg, bool* need_split); | |
745 int find_free_double_reg(int reg_needed_until, int interval_to, int hint_reg, bool* need_split); | |
746 bool alloc_free_reg(Interval* cur); | |
747 | |
748 int find_locked_reg(int reg_needed_until, int interval_to, int hint_reg, int ignore_reg, bool* need_split); | |
749 int find_locked_double_reg(int reg_needed_until, int interval_to, int hint_reg, bool* need_split); | |
750 void split_and_spill_intersecting_intervals(int reg, int regHi); | |
751 void alloc_locked_reg(Interval* cur); | |
752 | |
753 bool no_allocation_possible(Interval* cur); | |
754 void update_phys_reg_range(bool requires_cpu_register); | |
755 void init_vars_for_alloc(Interval* cur); | |
756 bool pd_init_regs_for_alloc(Interval* cur); | |
757 | |
758 void combine_spilled_intervals(Interval* cur); | |
759 bool is_move(LIR_Op* op, Interval* from, Interval* to); | |
760 | |
761 bool activate_current(); | |
762 | |
763 public: | |
764 LinearScanWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first); | |
765 | |
766 // must be called when all intervals are allocated | |
767 void finish_allocation() { _move_resolver.resolve_and_append_moves(); } | |
768 }; | |
769 | |
770 | |
771 | |
772 /* | |
773 When a block has more than one predecessor, and all predecessors end with | |
774 the same sequence of move-instructions, than this moves can be placed once | |
775 at the beginning of the block instead of multiple times in the predecessors. | |
776 | |
777 Similarly, when a block has more than one successor, then equal sequences of | |
778 moves at the beginning of the successors can be placed once at the end of | |
779 the block. But because the moves must be inserted before all branch | |
780 instructions, this works only when there is exactly one conditional branch | |
781 at the end of the block (because the moves must be inserted before all | |
782 branches, but after all compares). | |
783 | |
784 This optimization affects all kind of moves (reg->reg, reg->stack and | |
785 stack->reg). Because this optimization works best when a block contains only | |
786 few moves, it has a huge impact on the number of blocks that are totally | |
787 empty. | |
788 */ | |
789 class EdgeMoveOptimizer : public StackObj { | |
790 private: | |
791 // the class maintains a list with all lir-instruction-list of the | |
792 // successors (predecessors) and the current index into the lir-lists | |
793 LIR_OpListStack _edge_instructions; | |
794 intStack _edge_instructions_idx; | |
795 | |
796 void init_instructions(); | |
797 void append_instructions(LIR_OpList* instructions, int instructions_idx); | |
798 LIR_Op* instruction_at(int edge); | |
799 void remove_cur_instruction(int edge, bool decrement_index); | |
800 | |
801 bool operations_different(LIR_Op* op1, LIR_Op* op2); | |
802 | |
803 void optimize_moves_at_block_end(BlockBegin* cur); | |
804 void optimize_moves_at_block_begin(BlockBegin* cur); | |
805 | |
806 EdgeMoveOptimizer(); | |
807 | |
808 public: | |
809 static void optimize(BlockList* code); | |
810 }; | |
811 | |
812 | |
813 | |
814 class ControlFlowOptimizer : public StackObj { | |
815 private: | |
816 BlockList _original_preds; | |
817 | |
818 enum { | |
819 ShortLoopSize = 5 | |
820 }; | |
821 void reorder_short_loop(BlockList* code, BlockBegin* header_block, int header_idx); | |
822 void reorder_short_loops(BlockList* code); | |
823 | |
824 bool can_delete_block(BlockBegin* cur); | |
825 void substitute_branch_target(BlockBegin* cur, BlockBegin* target_from, BlockBegin* target_to); | |
826 void delete_empty_blocks(BlockList* code); | |
827 | |
828 void delete_unnecessary_jumps(BlockList* code); | |
829 void delete_jumps_to_return(BlockList* code); | |
830 | |
831 DEBUG_ONLY(void verify(BlockList* code);) | |
832 | |
833 ControlFlowOptimizer(); | |
834 public: | |
835 static void optimize(BlockList* code); | |
836 }; | |
837 | |
838 | |
839 #ifndef PRODUCT | |
840 | |
841 // Helper class for collecting statistics of LinearScan | |
842 class LinearScanStatistic : public StackObj { | |
843 public: | |
844 enum Counter { | |
845 // general counters | |
846 counter_method, | |
847 counter_fpu_method, | |
848 counter_loop_method, | |
849 counter_exception_method, | |
850 counter_loop, | |
851 counter_block, | |
852 counter_loop_block, | |
853 counter_exception_block, | |
854 counter_interval, | |
855 counter_fixed_interval, | |
856 counter_range, | |
857 counter_fixed_range, | |
858 counter_use_pos, | |
859 counter_fixed_use_pos, | |
860 counter_spill_slots, | |
861 blank_line_1, | |
862 | |
863 // counter for classes of lir instructions | |
864 counter_instruction, | |
865 counter_label, | |
866 counter_entry, | |
867 counter_return, | |
868 counter_call, | |
869 counter_move, | |
870 counter_cmp, | |
871 counter_cond_branch, | |
872 counter_uncond_branch, | |
873 counter_stub_branch, | |
874 counter_alu, | |
875 counter_alloc, | |
876 counter_sync, | |
877 counter_throw, | |
878 counter_unwind, | |
879 counter_typecheck, | |
880 counter_fpu_stack, | |
881 counter_misc_inst, | |
882 counter_other_inst, | |
883 blank_line_2, | |
884 | |
885 // counter for different types of moves | |
886 counter_move_total, | |
887 counter_move_reg_reg, | |
888 counter_move_reg_stack, | |
889 counter_move_stack_reg, | |
890 counter_move_stack_stack, | |
891 counter_move_reg_mem, | |
892 counter_move_mem_reg, | |
893 counter_move_const_any, | |
894 | |
895 number_of_counters, | |
896 invalid_counter = -1 | |
897 }; | |
898 | |
899 private: | |
900 int _counters_sum[number_of_counters]; | |
901 int _counters_max[number_of_counters]; | |
902 | |
903 void inc_counter(Counter idx, int value = 1) { _counters_sum[idx] += value; } | |
904 | |
905 const char* counter_name(int counter_idx); | |
906 Counter base_counter(int counter_idx); | |
907 | |
908 void sum_up(LinearScanStatistic &method_statistic); | |
909 void collect(LinearScan* allocator); | |
910 | |
911 public: | |
912 LinearScanStatistic(); | |
913 void print(const char* title); | |
914 static void compute(LinearScan* allocator, LinearScanStatistic &global_statistic); | |
915 }; | |
916 | |
917 | |
918 // Helper class for collecting compilation time of LinearScan | |
919 class LinearScanTimers : public StackObj { | |
920 public: | |
921 enum Timer { | |
922 timer_do_nothing, | |
923 timer_number_instructions, | |
924 timer_compute_local_live_sets, | |
925 timer_compute_global_live_sets, | |
926 timer_build_intervals, | |
927 timer_sort_intervals_before, | |
928 timer_allocate_registers, | |
929 timer_resolve_data_flow, | |
930 timer_sort_intervals_after, | |
931 timer_eliminate_spill_moves, | |
932 timer_assign_reg_num, | |
933 timer_allocate_fpu_stack, | |
934 timer_optimize_lir, | |
935 | |
936 number_of_timers | |
937 }; | |
938 | |
939 private: | |
940 elapsedTimer _timers[number_of_timers]; | |
941 const char* timer_name(int idx); | |
942 | |
943 public: | |
944 LinearScanTimers(); | |
945 | |
946 void begin_method(); // called for each method when register allocation starts | |
947 void end_method(LinearScan* allocator); // called for each method when register allocation completed | |
948 void print(double total_time); // called before termination of VM to print global summary | |
949 | |
950 elapsedTimer* timer(int idx) { return &(_timers[idx]); } | |
951 }; | |
952 | |
953 | |
954 #endif // ifndef PRODUCT | |
955 | |
956 | |
957 // Pick up platform-dependent implementation details | |
958 # include "incls/_c1_LinearScan_pd.hpp.incl" |