1 /*
2 * Copyright (c) 2024, 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.incubator.code.bytecode;
27
28 import java.lang.classfile.ClassBuilder;
29 import java.lang.classfile.ClassFile;
30 import java.lang.classfile.ClassModel;
31 import java.lang.classfile.CodeBuilder;
32 import java.lang.classfile.Label;
33 import java.lang.classfile.Opcode;
34 import java.lang.classfile.TypeKind;
35 import java.lang.constant.ClassDesc;
36 import java.lang.constant.Constable;
37 import java.lang.constant.ConstantDescs;
38 import java.lang.constant.DirectMethodHandleDesc;
39 import java.lang.constant.DynamicCallSiteDesc;
40 import java.lang.constant.MethodHandleDesc;
41 import java.lang.constant.MethodTypeDesc;
42 import java.lang.invoke.LambdaMetafactory;
43 import java.lang.invoke.MethodHandle;
44 import java.lang.invoke.MethodHandles;
45 import java.lang.invoke.MethodType;
46 import java.lang.invoke.StringConcatFactory;
47 import java.lang.reflect.Method;
48 import java.lang.reflect.Modifier;
49 import jdk.incubator.code.Block;
50 import jdk.incubator.code.Op;
51 import jdk.incubator.code.Quotable;
52 import jdk.incubator.code.Quoted;
53 import jdk.incubator.code.TypeElement;
54 import jdk.incubator.code.Value;
55 import jdk.incubator.code.bytecode.impl.BranchCompactor;
56 import jdk.incubator.code.bytecode.impl.LocalsCompactor;
57 import jdk.incubator.code.dialect.core.CoreOp.*;
58 import jdk.incubator.code.dialect.core.CoreType;
59 import jdk.incubator.code.dialect.java.*;
60 import jdk.incubator.code.extern.OpParser;
61 import jdk.incubator.code.dialect.core.FunctionType;
62 import jdk.incubator.code.dialect.core.VarType;
63 import java.util.ArrayList;
64 import java.util.Arrays;
65 import java.util.BitSet;
66 import java.util.IdentityHashMap;
67 import java.util.List;
68 import java.util.Map;
69 import java.util.Set;
70 import java.util.stream.Stream;
71
72 import static java.lang.constant.ConstantDescs.*;
73 import static jdk.incubator.code.dialect.java.JavaOp.*;
74
75 /**
76 * Transformer of code models to bytecode.
77 */
78 public final class BytecodeGenerator {
79
80 private static final DirectMethodHandleDesc DMHD_LAMBDA_METAFACTORY = ofCallsiteBootstrap(
81 LambdaMetafactory.class.describeConstable().orElseThrow(),
82 "metafactory",
83 CD_CallSite, CD_MethodType, CD_MethodHandle, CD_MethodType);
84
85 private static final DirectMethodHandleDesc DMHD_LAMBDA_ALT_METAFACTORY = ofCallsiteBootstrap(
86 LambdaMetafactory.class.describeConstable().orElseThrow(),
87 "altMetafactory",
88 CD_CallSite, CD_Object.arrayType());
89
90 private static final DirectMethodHandleDesc DMHD_STRING_CONCAT = ofCallsiteBootstrap(
91 StringConcatFactory.class.describeConstable().orElseThrow(),
92 "makeConcat",
93 CD_CallSite);
94
95 private static final MethodTypeDesc OP_METHOD_DESC = MethodTypeDesc.of(Op.class.describeConstable().get());
96
97 /**
98 * Transforms the invokable operation to bytecode encapsulated in a method of hidden class and exposed
99 * for invocation via a method handle.
100 *
101 * @param l the lookup
102 * @param iop the invokable operation to transform to bytecode
103 * @return the invoking method handle
104 * @param <O> the type of the invokable operation
105 */
106 public static <O extends Op & Op.Invokable> MethodHandle generate(MethodHandles.Lookup l, O iop) {
107 String name = iop instanceof FuncOp fop ? fop.funcName() : "m";
108 byte[] classBytes = generateClassData(l, name, iop);
109
110 MethodHandles.Lookup hcl;
111 try {
112 hcl = l.defineHiddenClass(classBytes, true, MethodHandles.Lookup.ClassOption.NESTMATE);
113 } catch (IllegalAccessException e) {
114 throw new RuntimeException(e);
115 }
116
117 try {
118 FunctionType ft = iop.invokableType();
119 MethodType mt = MethodRef.toNominalDescriptor(ft).resolveConstantDesc(hcl);
120 return hcl.findStatic(hcl.lookupClass(), name, mt);
121 } catch (ReflectiveOperationException e) {
122 throw new RuntimeException(e);
123 }
124 }
125
126 /**
127 * Transforms the function operation to bytecode encapsulated in a method of a class file.
128 * <p>
129 * The name of the method is the function operation's {@link FuncOp#funcName() function name}.
130 *
131 * @param lookup the lookup
132 * @param fop the function operation to transform to bytecode
133 * @return the class file bytes
134 */
135 public static byte[] generateClassData(MethodHandles.Lookup lookup, FuncOp fop) {
136 ClassModel generatedModel = ClassFile.of().parse(generateClassData(lookup, fop.funcName(), fop));
137 // Compact locals of the generated bytecode
138 return ClassFile.of().transformClass(generatedModel, LocalsCompactor.INSTANCE);
139 }
140
141 /**
142 * Transforms the invokable operation to bytecode encapsulated in a method of a class file.
143 *
144 * @param lookup the lookup
145 * @param name the name to use for the method of the class file
146 * @param iop the invokable operation to transform to bytecode
147 * @return the class file bytes
148 * @param <O> the type of the invokable operation
149 */
150 public static <O extends Op & Op.Invokable> byte[] generateClassData(MethodHandles.Lookup lookup,
151 String name,
152 O iop) {
153 if (!iop.capturedValues().isEmpty()) {
154 throw new UnsupportedOperationException("Operation captures values");
155 }
156
157 String packageName = lookup.lookupClass().getPackageName();
158 ClassDesc className = ClassDesc.of(packageName.isEmpty()
159 ? name
160 : packageName + "." + name);
161 byte[] classBytes = ClassFile.of().build(className, clb -> {
162 List<LambdaOp> lambdaSink = new ArrayList<>();
163 BitSet quotable = new BitSet();
164 generateMethod(lookup, className, name, iop, clb, lambdaSink, quotable);
165 for (int i = 0; i < lambdaSink.size(); i++) {
166 LambdaOp lop = lambdaSink.get(i);
167 if (quotable.get(i)) {
168 // return (FuncOp) OpParser.fromOpString(opText)
169 clb.withMethod("op$lambda$" + i, OP_METHOD_DESC,
170 ClassFile.ACC_PRIVATE | ClassFile.ACC_STATIC | ClassFile.ACC_SYNTHETIC, mb -> mb.withCode(cb -> cb
171 .loadConstant(Quoted.quoteOp(lop).toText())
172 .invoke(Opcode.INVOKESTATIC, OpParser.class.describeConstable().get(),
173 "fromStringOfJavaCodeModel",
174 MethodTypeDesc.of(Op.class.describeConstable().get(), CD_String), false)
175 .areturn()));
176 }
177 generateMethod(lookup, className, "lambda$" + i, lop, clb, lambdaSink, quotable);
178 }
179 });
180 return classBytes;
181 }
182
183 private static <O extends Op & Op.Invokable> void generateMethod(MethodHandles.Lookup lookup,
184 ClassDesc className,
185 String methodName,
186 O iop,
187 ClassBuilder clb,
188 List<LambdaOp> lambdaSink,
189 BitSet quotable) {
190
191 List<Value> capturedValues = iop instanceof LambdaOp lop ? lop.capturedValues() : List.of();
192 MethodTypeDesc mtd = MethodRef.toNominalDescriptor(
193 iop.invokableType()).insertParameterTypes(0, capturedValues.stream()
194 .map(Value::type).map(BytecodeGenerator::toClassDesc).toArray(ClassDesc[]::new));
195 clb.withMethodBody(methodName, mtd, ClassFile.ACC_PUBLIC | ClassFile.ACC_STATIC,
196 cb -> cb.transforming(new BranchCompactor(), cob ->
197 new BytecodeGenerator(lookup, className, capturedValues, TypeKind.from(mtd.returnType()),
198 iop.body().blocks(), cob, lambdaSink, quotable).generate()));
199 }
200
201 private record Slot(int slot, TypeKind typeKind) {}
202
203 private final MethodHandles.Lookup lookup;
204 private final ClassDesc className;
205 private final List<Value> capturedValues;
206 private final TypeKind returnType;
207 private final List<Block> blocks;
208 private final CodeBuilder cob;
209 private final Label[] blockLabels;
210 private final Block[][] blocksCatchMap;
211 private final BitSet allCatchBlocks;
212 private final Label[] tryStartLabels;
213 private final Map<Value, Slot> slots;
214 private final Map<Block.Parameter, Value> singlePredecessorsValues;
215 private final List<LambdaOp> lambdaSink;
216 private final BitSet quotable;
217 private final Map<Op, Boolean> deferCache;
218 private Value oprOnStack;
219 private Block[] recentCatchBlocks;
220
221 private BytecodeGenerator(MethodHandles.Lookup lookup,
222 ClassDesc className,
223 List<Value> capturedValues,
224 TypeKind returnType,
225 List<Block> blocks,
226 CodeBuilder cob,
227 List<LambdaOp> lambdaSink,
228 BitSet quotable) {
229 this.lookup = lookup;
230 this.className = className;
231 this.capturedValues = capturedValues;
232 this.returnType = returnType;
233 this.blocks = blocks;
234 this.cob = cob;
235 this.blockLabels = new Label[blocks.size()];
236 this.blocksCatchMap = new Block[blocks.size()][];
237 this.allCatchBlocks = new BitSet();
238 this.tryStartLabels = new Label[blocks.size()];
239 this.slots = new IdentityHashMap<>();
240 this.singlePredecessorsValues = new IdentityHashMap<>();
241 this.lambdaSink = lambdaSink;
242 this.quotable = quotable;
243 this.deferCache = new IdentityHashMap<>();
244 }
245
246 private void setCatchStack(Block.Reference target, Block[] activeCatchBlocks) {
247 setCatchStack(target.targetBlock().index(), activeCatchBlocks);
248 }
249
250 private void setCatchStack(int blockIndex, Block[] activeCatchBlocks) {
251 Block[] prevStack = blocksCatchMap[blockIndex];
252 if (prevStack == null) {
253 blocksCatchMap[blockIndex] = activeCatchBlocks;
254 } else {
255 assert Arrays.equals(prevStack, activeCatchBlocks);
256 }
257 }
258
259 private Label getLabel(Block.Reference target) {
260 return getLabel(target.targetBlock().index());
261 }
262
263 private Label getLabel(int blockIndex) {
264 if (blockIndex == blockLabels.length) {
265 return cob.endLabel();
266 }
267 Label l = blockLabels[blockIndex];
268 if (l == null) {
269 blockLabels[blockIndex] = l = cob.newLabel();
270 }
271 return l;
272 }
273
274 private Slot allocateSlot(Value v) {
275 return slots.computeIfAbsent(v, _ -> {
276 TypeKind tk = toTypeKind(v.type());
277 return new Slot(cob.allocateLocal(tk), tk);
278 });
279 }
280
281 private void storeIfUsed(Value v) {
282 if (!v.uses().isEmpty()) {
283 Slot slot = allocateSlot(v);
284 cob.storeLocal(slot.typeKind(), slot.slot());
285 } else {
286 // Only pop results from stack if the value has no further use (no valid slot)
287 switch (toTypeKind(v.type()).slotSize()) {
288 case 1 -> cob.pop();
289 case 2 -> cob.pop2();
290 }
291 }
292 }
293
294 private void load(Value v) {
295 v = singlePredecessorsValues.getOrDefault(v, v);
296 if (v instanceof Op.Result or &&
297 or.op() instanceof ConstantOp constantOp &&
298 !constantOp.resultType().equals(JavaType.J_L_CLASS)) {
299 cob.loadConstant(switch (constantOp.value()) {
300 case null -> null;
301 case Boolean b -> {
302 yield b ? 1 : 0;
303 }
304 case Byte b -> (int)b;
305 case Character ch -> (int)ch;
306 case Short s -> (int)s;
307 case Constable c -> c.describeConstable().orElseThrow();
308 default -> throw new IllegalArgumentException("Unexpected constant value: " + constantOp.value());
309 });
310 } else {
311 Slot slot = slots.get(v);
312 if (slot == null) {
313 if (v instanceof Op.Result or) {
314 // Handling of deferred variables
315 switch (or.op()) {
316 case VarOp vop ->
317 load(vop.initOperand());
318 case VarAccessOp.VarLoadOp vlop ->
319 load(vlop.varOperand());
320 default ->
321 throw new IllegalStateException("Missing slot for: " + or.op());
322 }
323 } else {
324 throw new IllegalStateException("Missing slot for: " + v);
325 }
326 } else {
327 cob.loadLocal(slot.typeKind(), slot.slot());
328 }
329 }
330 }
331
332 private void processFirstOperand(Op op) {
333 processOperand(op.operands().getFirst());
334 }
335
336 private void processOperand(Value operand) {
337 if (oprOnStack == null) {
338 load(operand);
339 } else {
340 assert oprOnStack == operand;
341 oprOnStack = null;
342 }
343 }
344
345 private void processOperands(Op op) {
346 processOperands(op.operands());
347 }
348
349 private void processOperands(List<Value> operands) {
350 if (oprOnStack == null) {
351 operands.forEach(this::load);
352 } else {
353 assert !operands.isEmpty() && oprOnStack == operands.getFirst();
354 oprOnStack = null;
355 for (int i = 1; i < operands.size(); i++) {
356 load(operands.get(i));
357 }
358 }
359 }
360
361 // Some of the operations can be deferred
362 private boolean canDefer(Op op) {
363 Boolean can = deferCache.get(op);
364 if (can == null) {
365 can = switch (op) {
366 case ConstantOp cop -> canDefer(cop);
367 case VarOp vop -> canDefer(vop);
368 case VarAccessOp.VarLoadOp vlop -> canDefer(vlop);
369 default -> false;
370 };
371 deferCache.put(op, can);
372 }
373 return can;
374 }
375
376 // Constant can be deferred, except for loading of a class constant, which may throw an exception
377 private static boolean canDefer(ConstantOp op) {
378 return !op.resultType().equals(JavaType.J_L_CLASS);
379 }
380
381 // Single-use var or var with a single-use entry block parameter operand can be deferred
382 private static boolean canDefer(VarOp op) {
383 return op.isUninitialized()
384 || !moreThanOneUse(op.result())
385 || op.initOperand() instanceof Block.Parameter bp && bp.declaringBlock().isEntryBlock() && !moreThanOneUse(bp);
386 }
387
388 // Var load can be deferred when not used as immediate operand
389 private boolean canDefer(VarAccessOp.VarLoadOp op) {
390 return !isNextUse(op.result());
391 }
392
393 // This method narrows the first operand inconveniences of some operations
394 private static boolean isFirstOperand(Op nextOp, Value opr) {
395 List<Value> values;
396 return switch (nextOp) {
397 // When there is no next operation
398 case null -> false;
399 // New object cannot use first operand from stack, new array fall through to the default
400 case NewOp op when !(op.constructorDescriptor().type().returnType() instanceof ArrayType) ->
401 false;
402 // For lambda the effective operands are captured values
403 case LambdaOp op ->
404 !(values = op.capturedValues()).isEmpty() && values.getFirst() == opr;
405 // Conditional branch may delegate to its binary test operation
406 case ConditionalBranchOp op when getConditionForCondBrOp(op) instanceof BinaryTestOp bto ->
407 isFirstOperand(bto, opr);
408 // Var store effective first operand is not the first one
409 case VarAccessOp.VarStoreOp op ->
410 op.operands().get(1) == opr;
411 // Unconditional branch first target block argument
412 case BranchOp op ->
413 !(values = op.branch().arguments()).isEmpty() && values.getFirst() == opr;
414 // regular check of the first operand
415 default ->
416 !(values = nextOp.operands()).isEmpty() && values.getFirst() == opr;
417 };
418 }
419
420 // Determines if the operation result is immediatelly used by the next operation and so can stay on stack
421 private boolean isNextUse(Value opr) {
422 Op nextOp = switch (opr) {
423 case Block.Parameter p -> p.declaringBlock().firstOp();
424 case Op.Result r -> r.declaringBlock().nextOp(r.op());
425 };
426 // Pass over deferred operations
427 while (canDefer(nextOp)) {
428 nextOp = nextOp.parentBlock().nextOp(nextOp);
429 }
430 return isFirstOperand(nextOp, opr);
431 }
432
433 private static boolean isConditionForCondBrOp(BinaryTestOp op) {
434 // Result of op has one use as the operand of a CondBrOp op,
435 // and both ops are in the same block
436
437 Set<Op.Result> uses = op.result().uses();
438 if (uses.size() != 1) {
439 return false;
440 }
441 Op.Result use = uses.iterator().next();
442
443 if (use.declaringBlock() != op.parentBlock()) {
444 return false;
445 }
446
447 // Check if used in successor
448 for (Block.Reference s : use.op().successors()) {
449 if (s.arguments().contains(op.result())) {
450 return false;
451 }
452 }
453
454 return use.op() instanceof ConditionalBranchOp;
455 }
456
457 static ClassDesc toClassDesc(TypeElement t) {
458 return switch (t) {
459 case VarType vt -> toClassDesc(vt.valueType());
460 case JavaType jt -> jt.toNominalDescriptor();
461 default ->
462 throw new IllegalArgumentException("Bad type: " + t);
463 };
464 }
465
466 static TypeKind toTypeKind(TypeElement t) {
467 return switch (t) {
468 case VarType vt -> toTypeKind(vt.valueType());
469 case PrimitiveType pt -> TypeKind.from(pt.toNominalDescriptor());
470 case JavaType _ -> TypeKind.REFERENCE;
471 default ->
472 throw new IllegalArgumentException("Bad type: " + t);
473 };
474 }
475
476 private void generate() {
477 recentCatchBlocks = new Block[0];
478
479 Block entryBlock = blocks.getFirst();
480 assert entryBlock.isEntryBlock();
481
482 // Entry block parameters conservatively require slots
483 // Some unused parameters might be declared before others that are used
484 List<Block.Parameter> parameters = entryBlock.parameters();
485 int paramSlot = 0;
486 // Captured values prepend parameters in lambda impl methods
487 for (Value cv : capturedValues) {
488 slots.put(cv, new Slot(cob.parameterSlot(paramSlot++), toTypeKind(cv.type())));
489 }
490 for (Block.Parameter bp : parameters) {
491 slots.put(bp, new Slot(cob.parameterSlot(paramSlot++), toTypeKind(bp.type())));
492 }
493
494 blocksCatchMap[entryBlock.index()] = new Block[0];
495
496 // Process blocks in topological order
497 // A jump instruction assumes the false successor block is
498 // immediately after, in sequence, to the predecessor
499 // since the jump instructions branch on a true condition
500 // Conditions are inverted when lowered to bytecode
501 for (Block b : blocks) {
502
503 Block[] catchBlocks = blocksCatchMap[b.index()];
504
505 // Ignore inaccessible blocks
506 if (catchBlocks == null) {
507 continue;
508 }
509
510 Label blockLabel = getLabel(b.index());
511 cob.labelBinding(blockLabel);
512
513 oprOnStack = null;
514
515 // If b is a catch block then the exception argument will be represented on the stack
516 if (allCatchBlocks.get(b.index())) {
517 // Retain block argument for exception table generation
518 push(b.parameters().getFirst());
519 }
520
521 exceptionRegionsChange(catchBlocks);
522
523 List<Op> ops = b.ops();
524 for (int i = 0; i < ops.size() - 1; i++) {
525 final Op o = ops.get(i);
526 final TypeElement oprType = o.resultType();
527 final TypeKind rvt = toTypeKind(oprType);
528 switch (o) {
529 case ConstantOp op -> {
530 if (!canDefer(op)) {
531 // Constant can be deferred, except for a class constant, which may throw an exception
532 Object v = op.value();
533 if (v == null) {
534 cob.aconst_null();
535 } else {
536 cob.ldc(((JavaType)v).toNominalDescriptor());
537 }
538 push(op.result());
539 }
540 }
541 case VarOp op when op.isUninitialized() -> {
542 // Do nothing
543 }
544 case VarOp op -> {
545 // %1 : Var<int> = var %0 @"i";
546 if (canDefer(op)) {
547 Slot s = slots.get(op.operands().getFirst());
548 if (s != null) {
549 // Var with a single-use entry block parameter can reuse its slot
550 slots.put(op.result(), s);
551 }
552 } else {
553 processFirstOperand(op);
554 storeIfUsed(op.result());
555 }
556 }
557 case VarAccessOp.VarLoadOp op -> {
558 if (canDefer(op)) {
559 // Var load can be deferred when not used as immediate operand
560 slots.computeIfAbsent(op.result(), r -> slots.get(op.operands().getFirst()));
561 } else {
562 load(op.operands().getFirst());
563 push(op.result());
564 }
565 }
566 case VarAccessOp.VarStoreOp op -> {
567 processOperand(op.operands().get(1));
568 Slot slot = allocateSlot(op.operands().getFirst());
569 cob.storeLocal(slot.typeKind(), slot.slot());
570 }
571 case ConvOp op -> {
572 Value first = op.operands().getFirst();
573 processOperand(first);
574 cob.conversion(toTypeKind(first.type()), rvt);
575 push(op.result());
576 }
577 case NegOp op -> {
578 processFirstOperand(op);
579 switch (rvt) { //this can be moved to CodeBuilder::neg(TypeKind)
580 case INT, BOOLEAN, BYTE, SHORT, CHAR -> cob.ineg();
581 case LONG -> cob.lneg();
582 case FLOAT -> cob.fneg();
583 case DOUBLE -> cob.dneg();
584 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
585 }
586 push(op.result());
587 }
588 case ComplOp op -> {
589 // Lower to x ^ -1
590 processFirstOperand(op);
591 switch (rvt) {
592 case INT, BOOLEAN, BYTE, SHORT, CHAR -> {
593 cob.iconst_m1();
594 cob.ixor();
595 }
596 case LONG -> {
597 cob.ldc(-1L);
598 cob.lxor();
599 }
600 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
601 }
602 push(op.result());
603 }
604 case NotOp op -> {
605 processFirstOperand(op);
606 cob.ifThenElse(CodeBuilder::iconst_0, CodeBuilder::iconst_1);
607 push(op.result());
608 }
609 case AddOp op -> {
610 processOperands(op);
611 switch (rvt) { //this can be moved to CodeBuilder::add(TypeKind)
612 case INT, BOOLEAN, BYTE, SHORT, CHAR -> cob.iadd();
613 case LONG -> cob.ladd();
614 case FLOAT -> cob.fadd();
615 case DOUBLE -> cob.dadd();
616 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
617 }
618 push(op.result());
619 }
620 case SubOp op -> {
621 processOperands(op);
622 switch (rvt) { //this can be moved to CodeBuilder::sub(TypeKind)
623 case INT, BOOLEAN, BYTE, SHORT, CHAR -> cob.isub();
624 case LONG -> cob.lsub();
625 case FLOAT -> cob.fsub();
626 case DOUBLE -> cob.dsub();
627 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
628 }
629 push(op.result());
630 }
631 case MulOp op -> {
632 processOperands(op);
633 switch (rvt) { //this can be moved to CodeBuilder::mul(TypeKind)
634 case INT, BOOLEAN, BYTE, SHORT, CHAR -> cob.imul();
635 case LONG -> cob.lmul();
636 case FLOAT -> cob.fmul();
637 case DOUBLE -> cob.dmul();
638 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
639 }
640 push(op.result());
641 }
642 case DivOp op -> {
643 processOperands(op);
644 switch (rvt) { //this can be moved to CodeBuilder::div(TypeKind)
645 case INT, BOOLEAN, BYTE, SHORT, CHAR -> cob.idiv();
646 case LONG -> cob.ldiv();
647 case FLOAT -> cob.fdiv();
648 case DOUBLE -> cob.ddiv();
649 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
650 }
651 push(op.result());
652 }
653 case ModOp op -> {
654 processOperands(op);
655 switch (rvt) { //this can be moved to CodeBuilder::rem(TypeKind)
656 case INT, BOOLEAN, BYTE, SHORT, CHAR -> cob.irem();
657 case LONG -> cob.lrem();
658 case FLOAT -> cob.frem();
659 case DOUBLE -> cob.drem();
660 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
661 }
662 push(op.result());
663 }
664 case AndOp op -> {
665 processOperands(op);
666 switch (rvt) { //this can be moved to CodeBuilder::and(TypeKind)
667 case INT, BOOLEAN, BYTE, SHORT, CHAR -> cob.iand();
668 case LONG -> cob.land();
669 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
670 }
671 push(op.result());
672 }
673 case OrOp op -> {
674 processOperands(op);
675 switch (rvt) { //this can be moved to CodeBuilder::or(TypeKind)
676 case INT, BOOLEAN, BYTE, SHORT, CHAR -> cob.ior();
677 case LONG -> cob.lor();
678 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
679 }
680 push(op.result());
681 }
682 case XorOp op -> {
683 processOperands(op);
684 switch (rvt) { //this can be moved to CodeBuilder::xor(TypeKind)
685 case INT, BOOLEAN, BYTE, SHORT, CHAR -> cob.ixor();
686 case LONG -> cob.lxor();
687 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
688 }
689 push(op.result());
690 }
691 case LshlOp op -> {
692 processOperands(op);
693 adjustRightTypeToInt(op);
694 switch (rvt) { //this can be moved to CodeBuilder::shl(TypeKind)
695 case BYTE, CHAR, INT, SHORT -> cob.ishl();
696 case LONG -> cob.lshl();
697 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
698 }
699 push(op.result());
700 }
701 case AshrOp op -> {
702 processOperands(op);
703 adjustRightTypeToInt(op);
704 switch (rvt) { //this can be moved to CodeBuilder::shr(TypeKind)
705 case INT, BYTE, SHORT, CHAR -> cob.ishr();
706 case LONG -> cob.lshr();
707 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
708 }
709 push(op.result());
710 }
711 case LshrOp op -> {
712 processOperands(op);
713 adjustRightTypeToInt(op);
714 switch (rvt) { //this can be moved to CodeBuilder::ushr(TypeKind)
715 case INT, BYTE, SHORT, CHAR -> cob.iushr();
716 case LONG -> cob.lushr();
717 default -> throw new IllegalArgumentException("Bad type: " + op.resultType());
718 }
719 push(op.result());
720 }
721 case ArrayAccessOp.ArrayLoadOp op -> {
722 processOperands(op);
723 cob.arrayLoad(rvt);
724 push(op.result());
725 }
726 case ArrayAccessOp.ArrayStoreOp op -> {
727 processOperands(op);
728 cob.arrayStore(toTypeKind(((ArrayType)op.operands().getFirst().type()).componentType()));
729 push(op.result());
730 }
731 case ArrayLengthOp op -> {
732 processFirstOperand(op);
733 cob.arraylength();
734 push(op.result());
735 }
736 case BinaryTestOp op -> {
737 if (!isConditionForCondBrOp(op)) {
738 cob.ifThenElse(prepareConditionalBranch(op), CodeBuilder::iconst_0, CodeBuilder::iconst_1);
739 push(op.result());
740 }
741 // Processing is deferred to the CondBrOp, do not process the op result
742 }
743 case NewOp op -> {
744 switch (op.constructorDescriptor().type().returnType()) {
745 case ArrayType at -> {
746 processOperands(op);
747 if (at.dimensions() == 1) {
748 ClassDesc ctd = at.componentType().toNominalDescriptor();
749 if (ctd.isPrimitive()) {
750 cob.newarray(TypeKind.from(ctd));
751 } else {
752 cob.anewarray(ctd);
753 }
754 } else {
755 cob.multianewarray(at.toNominalDescriptor(), op.operands().size());
756 }
757 }
758 case JavaType jt -> {
759 cob.new_(jt.toNominalDescriptor())
760 .dup();
761 processOperands(op);
762 cob.invokespecial(
763 ((JavaType) op.resultType()).toNominalDescriptor(),
764 ConstantDescs.INIT_NAME,
765 MethodRef.toNominalDescriptor(op.constructorDescriptor().type())
766 .changeReturnType(ConstantDescs.CD_void));
767 }
768 default ->
769 throw new IllegalArgumentException("Invalid return type: "
770 + op.constructorDescriptor().type().returnType());
771 }
772 push(op.result());
773 }
774 case InvokeOp op -> {
775 if (op.isVarArgs()) {
776 processOperands(op.argOperands());
777 var varArgOperands = op.varArgOperands();
778 cob.loadConstant(varArgOperands.size());
779 var compType = ((ArrayType) op.invokeDescriptor().type().parameterTypes().getLast()).componentType();
780 var compTypeDesc = compType.toNominalDescriptor();
781 var typeKind = TypeKind.from(compTypeDesc);
782 if (compTypeDesc.isPrimitive()) {
783 cob.newarray(typeKind);
784 } else {
785 cob.anewarray(compTypeDesc);
786 }
787 for (int j = 0; j < varArgOperands.size(); j++) {
788 // we duplicate array value on the stack to be consumed by arrayStore
789 // after completion of this loop the array value will be on top of the stack
790 cob.dup();
791 cob.loadConstant(j);
792 load(varArgOperands.get(j));
793 cob.arrayStore(typeKind);
794 }
795 } else {
796 processOperands(op);
797 }
798 // Resolve referenced class to determine if interface
799 MethodRef md = op.invokeDescriptor();
800 JavaType refType = (JavaType)md.refType();
801 Class<?> refClass;
802 try {
803 refClass = (Class<?>)refType.erasure().resolve(lookup);
804 } catch (ReflectiveOperationException e) {
805 throw new IllegalArgumentException(e);
806 }
807 // Determine invoke opcode
808 final boolean isInterface = refClass.isInterface();
809 Opcode invokeOpcode = switch (op.invokeKind()) {
810 case STATIC ->
811 Opcode.INVOKESTATIC;
812 case INSTANCE ->
813 isInterface ? Opcode.INVOKEINTERFACE : Opcode.INVOKEVIRTUAL;
814 case SUPER ->
815 // @@@ We cannot generate an invokespecial as it will result in a verify error,
816 // since the owner is not assignable to generated hidden class
817 // @@@ Construct method handle via lookup.findSpecial
818 // using the lookup's class as the specialCaller and
819 // add that method handle to the to be defined hidden class's constant data
820 // Use and ldc+constant dynamic to access the class data,
821 // extract the method handle and then invoke it
822 throw new UnsupportedOperationException("invoke super unsupported: " + op.invokeDescriptor());
823 };
824 MethodTypeDesc mDesc = MethodRef.toNominalDescriptor(md.type());
825 cob.invoke(
826 invokeOpcode,
827 refType.toNominalDescriptor(),
828 md.name(),
829 mDesc,
830 isInterface);
831 ClassDesc ret = toClassDesc(op.resultType());
832 if (ret.isClassOrInterface() && !ret.equals(mDesc.returnType())) {
833 // Explicit cast if method return type differs
834 cob.checkcast(ret);
835 }
836 push(op.result());
837 }
838 case FieldAccessOp.FieldLoadOp op -> {
839 processOperands(op);
840 FieldRef fd = op.fieldDescriptor();
841 if (op.operands().isEmpty()) {
842 cob.getstatic(
843 ((JavaType) fd.refType()).toNominalDescriptor(),
844 fd.name(),
845 ((JavaType) fd.type()).toNominalDescriptor());
846 } else {
847 cob.getfield(
848 ((JavaType) fd.refType()).toNominalDescriptor(),
849 fd.name(),
850 ((JavaType) fd.type()).toNominalDescriptor());
851 }
852 push(op.result());
853 }
854 case FieldAccessOp.FieldStoreOp op -> {
855 processOperands(op);
856 FieldRef fd = op.fieldDescriptor();
857 if (op.operands().size() == 1) {
858 cob.putstatic(
859 ((JavaType) fd.refType()).toNominalDescriptor(),
860 fd.name(),
861 ((JavaType) fd.type()).toNominalDescriptor());
862 } else {
863 cob.putfield(
864 ((JavaType) fd.refType()).toNominalDescriptor(),
865 fd.name(),
866 ((JavaType) fd.type()).toNominalDescriptor());
867 }
868 }
869 case InstanceOfOp op -> {
870 processFirstOperand(op);
871 cob.instanceOf(((JavaType) op.type()).toNominalDescriptor());
872 push(op.result());
873 }
874 case CastOp op -> {
875 processFirstOperand(op);
876 cob.checkcast(((JavaType) op.type()).toNominalDescriptor());
877 push(op.result());
878 }
879 case LambdaOp op -> {
880 JavaType intfType = (JavaType)op.functionalInterface();
881 MethodTypeDesc mtd = MethodRef.toNominalDescriptor(op.invokableType());
882 try {
883 Class<?> intfClass = (Class<?>)intfType.erasure().resolve(lookup);
884 processOperands(op.capturedValues());
885 ClassDesc[] captureTypes = op.capturedValues().stream()
886 .map(Value::type).map(BytecodeGenerator::toClassDesc).toArray(ClassDesc[]::new);
887 int lambdaIndex = lambdaSink.size();
888 if (Quotable.class.isAssignableFrom(intfClass)) {
889 cob.invokedynamic(DynamicCallSiteDesc.of(
890 DMHD_LAMBDA_ALT_METAFACTORY,
891 funcIntfMethodName(intfClass),
892 MethodTypeDesc.of(intfType.toNominalDescriptor(),
893 captureTypes),
894 mtd,
895 MethodHandleDesc.ofMethod(DirectMethodHandleDesc.Kind.STATIC,
896 className,
897 "lambda$" + lambdaIndex,
898 mtd.insertParameterTypes(0, captureTypes)),
899 mtd,
900 LambdaMetafactory.FLAG_QUOTABLE,
901 MethodHandleDesc.ofMethod(DirectMethodHandleDesc.Kind.STATIC,
902 className,
903 "op$lambda$" + lambdaIndex,
904 OP_METHOD_DESC)));
905 quotable.set(lambdaSink.size());
906 } else {
907 cob.invokedynamic(DynamicCallSiteDesc.of(
908 DMHD_LAMBDA_METAFACTORY,
909 funcIntfMethodName(intfClass),
910 MethodTypeDesc.of(intfType.toNominalDescriptor(), captureTypes),
911 mtd,
912 MethodHandleDesc.ofMethod(DirectMethodHandleDesc.Kind.STATIC,
913 className,
914 "lambda$" + lambdaIndex,
915 mtd.insertParameterTypes(0, captureTypes)),
916 mtd));
917 }
918 lambdaSink.add(op);
919 } catch (ReflectiveOperationException e) {
920 throw new IllegalArgumentException(e);
921 }
922 push(op.result());
923 }
924 case ConcatOp op -> {
925 processOperands(op);
926 cob.invokedynamic(DynamicCallSiteDesc.of(DMHD_STRING_CONCAT, MethodTypeDesc.of(CD_String,
927 toClassDesc(op.operands().get(0).type()),
928 toClassDesc(op.operands().get(1).type()))));
929 push(op.result());
930 }
931 case MonitorOp.MonitorEnterOp op -> {
932 processFirstOperand(op);
933 cob.monitorenter();
934 }
935 case MonitorOp.MonitorExitOp op -> {
936 processFirstOperand(op);
937 cob.monitorexit();
938 }
939 default ->
940 throw new UnsupportedOperationException("Unsupported operation: " + ops.get(i));
941 }
942 }
943 Op top = b.terminatingOp();
944 switch (top) {
945 case ReturnOp op -> {
946 if (returnType != TypeKind.VOID) {
947 processFirstOperand(op);
948 // @@@ box, unbox, cast here ?
949 }
950 cob.return_(returnType);
951 }
952 case ThrowOp op -> {
953 processFirstOperand(op);
954 cob.athrow();
955 }
956 case BranchOp op -> {
957 setCatchStack(op.branch(), recentCatchBlocks);
958
959 assignBlockArguments(op.branch());
960 cob.goto_(getLabel(op.branch()));
961 }
962 case ConditionalBranchOp op -> {
963 setCatchStack(op.trueBranch(), recentCatchBlocks);
964 setCatchStack(op.falseBranch(), recentCatchBlocks);
965
966 if (getConditionForCondBrOp(op) instanceof BinaryTestOp btop) {
967 // Processing of the BinaryTestOp was deferred, so it can be merged with CondBrOp
968 conditionalBranch(prepareConditionalBranch(btop), op.trueBranch(), op.falseBranch());
969 } else {
970 processFirstOperand(op);
971 conditionalBranch(Opcode.IFEQ, op.trueBranch(), op.falseBranch());
972 }
973 }
974 case ExceptionRegionEnter op -> {
975 List<Block.Reference> enteringCatchBlocks = op.catchBlocks();
976 Block[] activeCatchBlocks = Arrays.copyOf(recentCatchBlocks, recentCatchBlocks.length + enteringCatchBlocks.size());
977 int i = recentCatchBlocks.length;
978 for (Block.Reference catchRef : enteringCatchBlocks) {
979 allCatchBlocks.set(catchRef.targetBlock().index());
980 activeCatchBlocks[i++] = catchRef.targetBlock();
981 setCatchStack(catchRef, recentCatchBlocks);
982 }
983 setCatchStack(op.start(), activeCatchBlocks);
984
985 assignBlockArguments(op.start());
986 cob.goto_(getLabel(op.start()));
987 }
988 case ExceptionRegionExit op -> {
989 List<Block.Reference> exitingCatchBlocks = op.catchBlocks();
990 Block[] activeCatchBlocks = Arrays.copyOf(recentCatchBlocks, recentCatchBlocks.length - exitingCatchBlocks.size());
991 setCatchStack(op.end(), activeCatchBlocks);
992
993 // Assert block exits in reverse order
994 int i = recentCatchBlocks.length;
995 for (Block.Reference catchRef : exitingCatchBlocks) {
996 assert catchRef.targetBlock() == recentCatchBlocks[--i];
997 }
998
999 assignBlockArguments(op.end());
1000 cob.goto_(getLabel(op.end()));
1001 }
1002 default ->
1003 throw new UnsupportedOperationException("Terminating operation not supported: " + top);
1004 }
1005 }
1006 exceptionRegionsChange(new Block[0]);
1007 }
1008
1009 private void exceptionRegionsChange(Block[] newCatchBlocks) {
1010 if (!Arrays.equals(recentCatchBlocks, newCatchBlocks)) {
1011 int i = recentCatchBlocks.length - 1;
1012 Label currentLabel = cob.newBoundLabel();
1013 // Exit catch blocks missing in the newCatchBlocks
1014 while (i >=0 && (i >= newCatchBlocks.length || recentCatchBlocks[i] != newCatchBlocks[i])) {
1015 Block catchBlock = recentCatchBlocks[i--];
1016 List<Block.Parameter> params = catchBlock.parameters();
1017 if (!params.isEmpty()) {
1018 JavaType jt = (JavaType) params.get(0).type();
1019 cob.exceptionCatch(tryStartLabels[catchBlock.index()], currentLabel, getLabel(catchBlock.index()), jt.toNominalDescriptor());
1020 } else {
1021 cob.exceptionCatchAll(tryStartLabels[catchBlock.index()], currentLabel, getLabel(catchBlock.index()));
1022 }
1023 tryStartLabels[catchBlock.index()] = null;
1024 }
1025 // Fill tryStartLabels for new entries
1026 while (++i < newCatchBlocks.length) {
1027 tryStartLabels[newCatchBlocks[i].index()] = currentLabel;
1028 }
1029 recentCatchBlocks = newCatchBlocks;
1030 }
1031 }
1032
1033 // Checks if the Op.Result is used more than once in operands and block arguments
1034 private static boolean moreThanOneUse(Value val) {
1035 return val.uses().stream().flatMap(u ->
1036 Stream.concat(
1037 u.op().operands().stream(),
1038 u.op().successors().stream()
1039 .flatMap(r -> r.arguments().stream())))
1040 .filter(val::equals).limit(2).count() > 1;
1041 }
1042
1043 private void push(Value res) {
1044 assert oprOnStack == null;
1045 if (res.type().equals(JavaType.VOID)) return;
1046 if (isNextUse(res)) {
1047 if (moreThanOneUse(res)) {
1048 switch (toTypeKind(res.type()).slotSize()) {
1049 case 1 -> cob.dup();
1050 case 2 -> cob.dup2();
1051 }
1052 storeIfUsed(res);
1053 }
1054 oprOnStack = res;
1055 } else {
1056 storeIfUsed(res);
1057 oprOnStack = null;
1058 }
1059 }
1060
1061 // the rhs of any shift instruction must be int or smaller -> convert longs
1062 private void adjustRightTypeToInt(Op op) {
1063 TypeElement right = op.operands().getLast().type();
1064 if (right.equals(JavaType.LONG)) {
1065 cob.conversion(toTypeKind(right), TypeKind.INT);
1066 }
1067 }
1068
1069 private static Op getConditionForCondBrOp(ConditionalBranchOp op) {
1070 Value p = op.predicate();
1071 if (p.uses().size() != 1) {
1072 return null;
1073 }
1074
1075 if (p.declaringBlock() != op.parentBlock()) {
1076 return null;
1077 }
1078
1079 // Check if used in successor
1080 for (Block.Reference s : op.successors()) {
1081 if (s.arguments().contains(p)) {
1082 return null;
1083 }
1084 }
1085
1086 if (p instanceof Op.Result or) {
1087 return or.op();
1088 } else {
1089 return null;
1090 }
1091 }
1092
1093 private String funcIntfMethodName(Class<?> intfc) {
1094 String uniqueName = null;
1095 for (Method m : intfc.getMethods()) {
1096 // ensure it's SAM interface
1097 String methodName = m.getName();
1098 if (Modifier.isAbstract(m.getModifiers())
1099 && (m.getReturnType() != String.class
1100 || m.getParameterCount() != 0
1101 || !methodName.equals("toString"))
1102 && (m.getReturnType() != int.class
1103 || m.getParameterCount() != 0
1104 || !methodName.equals("hashCode"))
1105 && (m.getReturnType() != boolean.class
1106 || m.getParameterCount() != 1
1107 || m.getParameterTypes()[0] != Object.class
1108 || !methodName.equals("equals"))) {
1109 if (uniqueName == null) {
1110 uniqueName = methodName;
1111 } else if (!uniqueName.equals(methodName)) {
1112 // too many abstract methods
1113 throw new IllegalArgumentException("Not a single-method interface: " + intfc.getName());
1114 }
1115 }
1116 }
1117 if (uniqueName == null) {
1118 throw new IllegalArgumentException("No method in: " + intfc.getName());
1119 }
1120 return uniqueName;
1121 }
1122
1123 private void conditionalBranch(Opcode reverseOpcode, Block.Reference trueBlock, Block.Reference falseBlock) {
1124 if (!needToAssignBlockArguments(falseBlock)) {
1125 cob.branch(reverseOpcode, getLabel(falseBlock));
1126 } else {
1127 cob.ifThen(reverseOpcode,
1128 bb -> {
1129 assignBlockArguments(falseBlock);
1130 bb.goto_(getLabel(falseBlock));
1131 });
1132 }
1133 assignBlockArguments(trueBlock);
1134 cob.goto_(getLabel(trueBlock));
1135 }
1136
1137 private Opcode prepareConditionalBranch(BinaryTestOp op) {
1138 Value firstOperand = op.operands().get(0);
1139 TypeKind typeKind = toTypeKind(firstOperand.type());
1140 Value secondOperand = op.operands().get(1);
1141 processOperand(firstOperand);
1142 if (isZeroIntOrNullConstant(secondOperand)) {
1143 return switch (typeKind) {
1144 case INT, BOOLEAN, BYTE, SHORT, CHAR ->
1145 switch (op) {
1146 case EqOp _ -> Opcode.IFNE;
1147 case NeqOp _ -> Opcode.IFEQ;
1148 case GtOp _ -> Opcode.IFLE;
1149 case GeOp _ -> Opcode.IFLT;
1150 case LtOp _ -> Opcode.IFGE;
1151 case LeOp _ -> Opcode.IFGT;
1152 default ->
1153 throw new UnsupportedOperationException(op.opName() + " on int");
1154 };
1155 case REFERENCE ->
1156 switch (op) {
1157 case EqOp _ -> Opcode.IFNONNULL;
1158 case NeqOp _ -> Opcode.IFNULL;
1159 default ->
1160 throw new UnsupportedOperationException(op.opName() + " on Object");
1161 };
1162 default ->
1163 throw new UnsupportedOperationException(op.opName() + " on " + op.operands().get(0).type());
1164 };
1165 }
1166 processOperand(secondOperand);
1167 return switch (typeKind) {
1168 case INT, BOOLEAN, BYTE, SHORT, CHAR ->
1169 switch (op) {
1170 case EqOp _ -> Opcode.IF_ICMPNE;
1171 case NeqOp _ -> Opcode.IF_ICMPEQ;
1172 case GtOp _ -> Opcode.IF_ICMPLE;
1173 case GeOp _ -> Opcode.IF_ICMPLT;
1174 case LtOp _ -> Opcode.IF_ICMPGE;
1175 case LeOp _ -> Opcode.IF_ICMPGT;
1176 default ->
1177 throw new UnsupportedOperationException(op.opName() + " on int");
1178 };
1179 case REFERENCE ->
1180 switch (op) {
1181 case EqOp _ -> Opcode.IF_ACMPNE;
1182 case NeqOp _ -> Opcode.IF_ACMPEQ;
1183 default ->
1184 throw new UnsupportedOperationException(op.opName() + " on Object");
1185 };
1186 case FLOAT -> {
1187 cob.fcmpg(); // FCMPL?
1188 yield reverseIfOpcode(op);
1189 }
1190 case LONG -> {
1191 cob.lcmp();
1192 yield reverseIfOpcode(op);
1193 }
1194 case DOUBLE -> {
1195 cob.dcmpg(); //CMPL?
1196 yield reverseIfOpcode(op);
1197 }
1198 default ->
1199 throw new UnsupportedOperationException(op.opName() + " on " + op.operands().get(0).type());
1200 };
1201 }
1202
1203 private boolean isZeroIntOrNullConstant(Value v) {
1204 return v instanceof Op.Result or
1205 && or.op() instanceof ConstantOp cop
1206 && switch (cop.value()) {
1207 case null -> true;
1208 case Integer i -> i == 0;
1209 case Boolean b -> !b;
1210 case Byte b -> b == 0;
1211 case Short s -> s == 0;
1212 case Character ch -> ch == 0;
1213 default -> false;
1214 };
1215 }
1216
1217 private static Opcode reverseIfOpcode(BinaryTestOp op) {
1218 return switch (op) {
1219 case EqOp _ -> Opcode.IFNE;
1220 case NeqOp _ -> Opcode.IFEQ;
1221 case GtOp _ -> Opcode.IFLE;
1222 case GeOp _ -> Opcode.IFLT;
1223 case LtOp _ -> Opcode.IFGE;
1224 case LeOp _ -> Opcode.IFGT;
1225 default ->
1226 throw new UnsupportedOperationException(op.opName());
1227 };
1228 }
1229
1230 private boolean needToAssignBlockArguments(Block.Reference ref) {
1231 List<Value> sargs = ref.arguments();
1232 List<Block.Parameter> bargs = ref.targetBlock().parameters();
1233 boolean need = false;
1234 for (int i = 0; i < bargs.size(); i++) {
1235 Block.Parameter barg = bargs.get(i);
1236 if (!barg.uses().isEmpty() && !barg.equals(sargs.get(i))) {
1237 need = true;
1238 allocateSlot(barg);
1239 }
1240 }
1241 return need;
1242 }
1243
1244 private void assignBlockArguments(Block.Reference ref) {
1245 Block target = ref.targetBlock();
1246 List<Value> sargs = ref.arguments();
1247 if (allCatchBlocks.get(target.index())) {
1248 // Jumping to an exception handler, exception parameter is expected on stack
1249 Value value = sargs.getFirst();
1250 if (oprOnStack == value) {
1251 oprOnStack = null;
1252 } else {
1253 load(value);
1254 }
1255 } else if (target.predecessors().size() > 1) {
1256 List<Block.Parameter> bargs = target.parameters();
1257 // First push successor arguments on the stack, then pop and assign
1258 // so as not to overwrite slots that are reused slots at different argument positions
1259 for (int i = 0; i < bargs.size(); i++) {
1260 Block.Parameter barg = bargs.get(i);
1261 Value value = sargs.get(i);
1262 if (!barg.uses().isEmpty() && !barg.equals(value)) {
1263 if (oprOnStack == value) {
1264 oprOnStack = null;
1265 } else {
1266 load(value);
1267 }
1268 storeIfUsed(barg);
1269 }
1270 }
1271 } else {
1272 // Single-predecessor block can just map parameter slots
1273 List<Block.Parameter> bargs = ref.targetBlock().parameters();
1274 for (int i = 0; i < bargs.size(); i++) {
1275 Value value = sargs.get(i);
1276 if (oprOnStack == value) {
1277 storeIfUsed(oprOnStack);
1278 oprOnStack = null;
1279 }
1280 // Map slot of the block argument to slot of the value
1281 singlePredecessorsValues.put(bargs.get(i), singlePredecessorsValues.getOrDefault(value, value));
1282 }
1283 }
1284 }
1285 }