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 jdk.internal.classfile.impl.BytecodeHelpers;
 29 
 30 import java.lang.classfile.Attributes;
 31 import java.lang.classfile.ClassFile;
 32 import java.lang.classfile.ClassModel;
 33 import java.lang.classfile.CodeElement;
 34 import java.lang.classfile.CodeModel;
 35 import java.lang.classfile.Instruction;
 36 import java.lang.classfile.Label;
 37 import java.lang.classfile.MethodModel;
 38 import java.lang.classfile.Opcode;
 39 import java.lang.classfile.PseudoInstruction;
 40 import java.lang.classfile.TypeKind;
 41 import java.lang.classfile.attribute.StackMapFrameInfo;
 42 import java.lang.classfile.instruction.*;
 43 import java.lang.constant.ClassDesc;
 44 import java.lang.constant.ConstantDesc;
 45 import java.lang.constant.ConstantDescs;
 46 import java.lang.constant.DirectMethodHandleDesc;
 47 import java.lang.constant.DynamicConstantDesc;
 48 import java.lang.constant.MethodTypeDesc;
 49 import java.lang.invoke.CallSite;
 50 import java.lang.invoke.MethodHandle;
 51 import java.lang.reflect.AccessFlag;
 52 import jdk.incubator.code.Block;
 53 import jdk.incubator.code.TypeElement;
 54 import jdk.incubator.code.op.CoreOp;
 55 import jdk.incubator.code.Op;
 56 import jdk.incubator.code.Value;
 57 import jdk.incubator.code.analysis.NormalizeBlocksTransformer;
 58 import jdk.incubator.code.type.FieldRef;
 59 import jdk.incubator.code.type.FunctionType;
 60 import jdk.incubator.code.type.JavaType;
 61 import jdk.incubator.code.type.MethodRef;
 62 import jdk.incubator.code.type.PrimitiveType;
 63 import jdk.incubator.code.type.VarType;
 64 import java.util.ArrayDeque;
 65 import java.util.ArrayList;
 66 import java.util.Arrays;
 67 import java.util.BitSet;
 68 import java.util.Collections;
 69 import java.util.Deque;
 70 import java.util.HashMap;
 71 import java.util.IdentityHashMap;
 72 import java.util.List;
 73 import java.util.Map;
 74 import java.util.stream.Collectors;
 75 import java.util.stream.IntStream;
 76 import java.util.stream.Stream;
 77 
 78 import static java.lang.classfile.attribute.StackMapFrameInfo.SimpleVerificationTypeInfo.*;
 79 
 80 public final class BytecodeLift {
 81 
 82     private static final ClassDesc CD_LambdaMetafactory = ClassDesc.ofDescriptor("Ljava/lang/invoke/LambdaMetafactory;");
 83     private static final ClassDesc CD_StringConcatFactory = ClassDesc.ofDescriptor("Ljava/lang/invoke/StringConcatFactory;");
 84     private static final JavaType MHS_LOOKUP = JavaType.type(ConstantDescs.CD_MethodHandles_Lookup);
 85     private static final JavaType MH = JavaType.type(ConstantDescs.CD_MethodHandle);
 86     private static final JavaType MT = JavaType.type(ConstantDescs.CD_MethodType);
 87     private static final JavaType CLASS_ARRAY = JavaType.array(JavaType.J_L_CLASS);
 88     private static final MethodRef LCMP = MethodRef.method(JavaType.J_L_LONG, "compare", JavaType.INT, JavaType.LONG, JavaType.LONG);
 89     private static final MethodRef FCMP = MethodRef.method(JavaType.J_L_FLOAT, "compare", JavaType.INT, JavaType.FLOAT, JavaType.FLOAT);
 90     private static final MethodRef DCMP = MethodRef.method(JavaType.J_L_DOUBLE, "compare", JavaType.INT, JavaType.DOUBLE, JavaType.DOUBLE);
 91     private static final MethodRef LOOKUP = MethodRef.method(JavaType.type(ConstantDescs.CD_MethodHandles), "lookup", MHS_LOOKUP);
 92     private static final MethodRef FIND_STATIC = MethodRef.method(MHS_LOOKUP, "findStatic", MH, JavaType.J_L_CLASS, JavaType.J_L_STRING, MT);
 93     private static final MethodRef FIND_VIRTUAL = MethodRef.method(MHS_LOOKUP, "findVirtual", MH, JavaType.J_L_CLASS, JavaType.J_L_STRING, MT);
 94     private static final MethodRef FIND_CONSTRUCTOR = MethodRef.method(MHS_LOOKUP, "findConstructor", MH, JavaType.J_L_CLASS, MT);
 95     private static final MethodRef FIND_GETTER = MethodRef.method(MHS_LOOKUP, "findGetter", MH, JavaType.J_L_CLASS, JavaType.J_L_STRING, JavaType.J_L_CLASS);
 96     private static final MethodRef FIND_STATIC_GETTER = MethodRef.method(MHS_LOOKUP, "findStaticGetter", MH, JavaType.J_L_CLASS, JavaType.J_L_STRING, JavaType.J_L_CLASS);
 97     private static final MethodRef FIND_SETTER = MethodRef.method(MHS_LOOKUP, "findSetter", MH, JavaType.J_L_CLASS, JavaType.J_L_STRING, JavaType.J_L_CLASS);
 98     private static final MethodRef FIND_STATIC_SETTER = MethodRef.method(MHS_LOOKUP, "findStaticSetter", MH, JavaType.J_L_CLASS, JavaType.J_L_STRING, JavaType.J_L_CLASS);
 99     private static final MethodRef METHOD_TYPE_0 = MethodRef.method(MT, "methodType", MT, JavaType.J_L_CLASS);
100     private static final MethodRef METHOD_TYPE_1 = MethodRef.method(MT, "methodType", MT, JavaType.J_L_CLASS, JavaType.J_L_CLASS);
101     private static final MethodRef METHOD_TYPE_L = MethodRef.method(MT, "methodType", MT, JavaType.J_L_CLASS, CLASS_ARRAY);
102 
103     private final Block.Builder entryBlock;
104     private final List<Value> initialValues;
105     private final ClassModel classModel;
106     private final List<Label> exceptionHandlers;
107     private final Map<Integer, Block.Builder> exceptionHandlerBlocks;
108     private final BitSet actualEreStack;
109     private final Map<Label, BitSet> exceptionHandlersMap;
110     private final Map<Label, Block.Builder> blockMap;
111     private final List<CodeElement> elements;
112     private final Deque<Value> stack;
113     private final Deque<ClassDesc> newStack;
114     private final List<ExceptionCatch> ecs;
115     private Block.Builder currentBlock;
116 
117     private BytecodeLift(Block.Builder entryBlock, ClassModel classModel, CodeModel codeModel, Value... capturedValues) {
118         this.entryBlock = entryBlock;
119         this.initialValues = Stream.concat(Stream.of(capturedValues), entryBlock.parameters().stream()).toList();
120         this.currentBlock = entryBlock;
121         this.classModel = classModel;
122         this.exceptionHandlers = new ArrayList<>();
123         this.exceptionHandlerBlocks = new HashMap<>();
124         this.actualEreStack = new BitSet();
125         this.newStack = new ArrayDeque<>();
126         this.elements = codeModel.elementList();
127         this.stack = new ArrayDeque<>();
128         this.exceptionHandlersMap = new IdentityHashMap<>();
129         this.blockMap = codeModel.findAttribute(Attributes.stackMapTable()).map(sma ->
130                 sma.entries().stream().collect(Collectors.toUnmodifiableMap(
131                         StackMapFrameInfo::target,
132                         smfi -> entryBlock.block(toBlockParams(smfi.stack()))))).orElseGet(Map::of);
133         this.ecs = codeModel.exceptionHandlers();
134         for (var ec : ecs.reversed()) {
135             if (exceptionHandlers.indexOf(ec.handler()) < 0) {
136                 exceptionHandlers.add(ec.handler());
137             }
138         }
139     }
140 
141     private List<TypeElement> toBlockParams(List<StackMapFrameInfo.VerificationTypeInfo> vtis) {
142         ArrayList<TypeElement> params = new ArrayList<>(vtis.size());
143         for (int i = vtis.size() - 1; i >= 0; i--) {
144             var vti = vtis.get(i);
145             switch (vti) {
146                 case INTEGER -> params.add(UnresolvedType.unresolvedInt());
147                 case FLOAT -> params.add(JavaType.FLOAT);
148                 case DOUBLE -> params.add(JavaType.DOUBLE);
149                 case LONG -> params.add(JavaType.LONG);
150                 case NULL -> params.add(UnresolvedType.unresolvedRef());
151                 case UNINITIALIZED_THIS ->
152                     params.add(JavaType.type(classModel.thisClass().asSymbol()));
153                 case StackMapFrameInfo.ObjectVerificationTypeInfo ovti ->
154                     params.add(JavaType.type(ovti.classSymbol()));
155 
156                     // Unitialized entry (a new object before its constructor is called)
157                     // must be skipped from block parameters because they do not exist in code reflection model
158                 case StackMapFrameInfo.UninitializedVerificationTypeInfo _ -> {}
159                 default ->
160                     throw new IllegalArgumentException("Unexpected VTI: " + vti);
161             }
162         }
163         return params;
164     }
165 
166     private Op.Result op(Op op) {
167         return currentBlock.op(op);
168     }
169 
170     // Lift to core dialect
171     public static CoreOp.FuncOp lift(byte[] classdata, String methodName) {
172         return lift(classdata, methodName, null);
173     }
174 
175     public static CoreOp.FuncOp lift(byte[] classdata, String methodName, MethodTypeDesc methodType) {
176         return lift(ClassFile.of(
177                 ClassFile.DebugElementsOption.DROP_DEBUG,
178                 ClassFile.LineNumbersOption.DROP_LINE_NUMBERS).parse(classdata).methods().stream()
179                         .filter(mm -> mm.methodName().equalsString(methodName) && (methodType == null || mm.methodTypeSymbol().equals(methodType)))
180                         .findFirst().orElseThrow(() -> new IllegalArgumentException("Unknown method: " + methodName)));
181     }
182 
183     public static CoreOp.FuncOp lift(MethodModel methodModel) {
184         ClassModel classModel = methodModel.parent().orElseThrow();
185         MethodTypeDesc mDesc = methodModel.methodTypeSymbol();
186         if (!methodModel.flags().has(AccessFlag.STATIC)) {
187             mDesc = mDesc.insertParameterTypes(0, classModel.thisClass().asSymbol());
188         }
189         return NormalizeBlocksTransformer.transform(
190                 UnresolvedTypesTransformer.transform(
191                     SlotToVarTransformer.transform(
192                         CoreOp.func(methodModel.methodName().stringValue(),
193                                     MethodRef.ofNominalDescriptor(mDesc)).body(entryBlock ->
194                                             new BytecodeLift(entryBlock,
195                                                              classModel,
196                                                              methodModel.code().orElseThrow()).liftBody()))));
197     }
198 
199     private void liftBody() {
200         // store entry block
201         int slot = 0;
202         for (var ep : initialValues) {
203             op(SlotOp.store(slot, ep));
204             slot += ep.type().equals(JavaType.LONG) || ep.type().equals(JavaType.DOUBLE) ? 2 : 1;
205         }
206 
207         // fill exceptionHandlersMap
208         BitSet eStack = new BitSet();
209         for (var e : elements) {
210             if (e instanceof LabelTarget lt) {
211                 BitSet newEreStack = null;
212                 for (var er : ecs) {
213                     if (lt.label() == er.tryStart() || lt.label() == er.tryEnd()) {
214                         if (newEreStack == null) newEreStack = (BitSet)eStack.clone();
215 
216                         newEreStack.set(exceptionHandlers.indexOf(er.handler()), lt.label() == er.tryStart());
217                     }
218                 }
219                 if (newEreStack != null || blockMap.containsKey(lt.label()))  {
220                     if (newEreStack != null) eStack = newEreStack;
221                     exceptionHandlersMap.put(lt.label(), eStack);
222                 }
223             }
224         }
225 
226         for (int i = 0; i < elements.size(); i++) {
227             switch (elements.get(i)) {
228                 case ExceptionCatch _ -> {
229                     // Exception blocks are inserted by label target (below)
230                 }
231                 case LabelTarget lt -> {
232                     BitSet newEreStack = exceptionHandlersMap.get(lt.label());
233                     if (newEreStack != null) {
234                         Block.Builder target = blockMap.get(lt.label());
235                         if (target != null) {
236                             if (currentBlock != null) {
237                                 // Transition to a branch target or a handler
238                                 ereTransit(actualEreStack, newEreStack, currentBlock, target, stackValues(target), exceptionHandlers.indexOf(lt.label()));
239                             }
240                             currentBlock = target;
241                             stack.clear();
242                             stack.addAll(target.parameters());
243                         } else if (currentBlock != null && !actualEreStack.equals(newEreStack)) {
244                             // Transition to a block with a different ERE stack
245                             Block.Builder next = entryBlock.block();
246                             ereTransit(actualEreStack, newEreStack, currentBlock, next, List.of(), -1);
247                             currentBlock = next;
248                         }
249                         actualEreStack.clear();
250                         actualEreStack.or(newEreStack);
251                     }
252                 }
253                 case BranchInstruction inst when BytecodeHelpers.isUnconditionalBranch(inst.opcode()) -> {
254                     Block.Builder target = blockMap.get(inst.target());
255                     ereTransit(actualEreStack, exceptionHandlersMap.get(inst.target()), currentBlock, target, stackValues(target), exceptionHandlers.indexOf(inst.target()));
256                     endOfFlow();
257                 }
258                 case BranchInstruction inst -> {
259                     // Conditional branch
260                     Value operand = stack.pop();
261                     Op cop = switch (inst.opcode()) {
262                         case IFNE -> CoreOp.eq(operand, liftConstant(0));
263                         case IFEQ -> CoreOp.neq(operand, liftConstant(0));
264                         case IFGE -> CoreOp.lt(operand, liftConstant(0));
265                         case IFLE -> CoreOp.gt(operand, liftConstant(0));
266                         case IFGT -> CoreOp.le(operand, liftConstant(0));
267                         case IFLT -> CoreOp.ge(operand, liftConstant(0));
268                         case IFNULL -> CoreOp.neq(operand, liftConstant(null));
269                         case IFNONNULL -> CoreOp.eq(operand, liftConstant(null));
270                         case IF_ICMPNE -> CoreOp.eq(stack.pop(), operand);
271                         case IF_ICMPEQ -> CoreOp.neq(stack.pop(), operand);
272                         case IF_ICMPGE -> CoreOp.lt(stack.pop(), operand);
273                         case IF_ICMPLE -> CoreOp.gt(stack.pop(), operand);
274                         case IF_ICMPGT -> CoreOp.le(stack.pop(), operand);
275                         case IF_ICMPLT -> CoreOp.ge(stack.pop(), operand);
276                         case IF_ACMPEQ -> CoreOp.neq(stack.pop(), operand);
277                         case IF_ACMPNE -> CoreOp.eq(stack.pop(), operand);
278                         default -> throw new UnsupportedOperationException("Unsupported branch instruction: " + inst);
279                     };
280                     Block.Builder branch = targetBlockForBranch(inst.target());
281                     Block.Builder next = entryBlock.block();
282                     op(CoreOp.conditionalBranch(op(cop),
283                             next.successor(),
284                             successorWithStack(branch)));
285                     currentBlock = next;
286                 }
287                 case LookupSwitchInstruction si -> {
288                     liftSwitch(si.defaultTarget(), si.cases());
289                 }
290                 case TableSwitchInstruction si -> {
291                     liftSwitch(si.defaultTarget(), si.cases());
292                 }
293                 case ReturnInstruction inst when inst.typeKind() == TypeKind.VOID -> {
294                     op(CoreOp._return());
295                     endOfFlow();
296                 }
297                 case ReturnInstruction _ -> {
298                     op(CoreOp._return(stack.pop()));
299                     endOfFlow();
300                 }
301                 case ThrowInstruction _ -> {
302                     op(CoreOp._throw(stack.pop()));
303                     endOfFlow();
304                 }
305                 case LoadInstruction inst -> {
306                     stack.push(op(SlotOp.load(inst.slot(), inst.typeKind())));
307                 }
308                 case StoreInstruction inst -> {
309                     op(SlotOp.store(inst.slot(), stack.pop()));
310                 }
311                 case IncrementInstruction inst -> {
312                     op(SlotOp.store(inst.slot(), op(CoreOp.add(op(SlotOp.load(inst.slot(), TypeKind.INT)), liftConstant(inst.constant())))));
313                 }
314                 case ConstantInstruction inst -> {
315                     stack.push(liftConstant(inst.constantValue()));
316                 }
317                 case ConvertInstruction inst -> {
318                     stack.push(op(CoreOp.conv(switch (inst.toType()) {
319                         case BYTE -> JavaType.BYTE;
320                         case SHORT -> JavaType.SHORT;
321                         case INT -> JavaType.INT;
322                         case FLOAT -> JavaType.FLOAT;
323                         case LONG -> JavaType.LONG;
324                         case DOUBLE -> JavaType.DOUBLE;
325                         case CHAR -> JavaType.CHAR;
326                         case BOOLEAN -> JavaType.BOOLEAN;
327                         default ->
328                             throw new IllegalArgumentException("Unsupported conversion target: " + inst.toType());
329                     }, stack.pop())));
330                 }
331                 case OperatorInstruction inst -> {
332                     TypeKind tk = inst.typeKind();
333                     Value operand = stack.pop();
334                     stack.push(op(switch (inst.opcode()) {
335                         case IADD, LADD, FADD, DADD ->
336                                 CoreOp.add(stack.pop(), operand);
337                         case ISUB, LSUB, FSUB, DSUB ->
338                                 CoreOp.sub(stack.pop(), operand);
339                         case IMUL, LMUL, FMUL, DMUL ->
340                                 CoreOp.mul(stack.pop(), operand);
341                         case IDIV, LDIV, FDIV, DDIV ->
342                                 CoreOp.div(stack.pop(), operand);
343                         case IREM, LREM, FREM, DREM ->
344                                 CoreOp.mod(stack.pop(), operand);
345                         case INEG, LNEG, FNEG, DNEG ->
346                                 CoreOp.neg(operand);
347                         case ARRAYLENGTH ->
348                                 CoreOp.arrayLength(operand);
349                         case IAND, LAND ->
350                                 CoreOp.and(stack.pop(), operand);
351                         case IOR, LOR ->
352                                 CoreOp.or(stack.pop(), operand);
353                         case IXOR, LXOR ->
354                                 CoreOp.xor(stack.pop(), operand);
355                         case ISHL, LSHL ->
356                                 CoreOp.lshl(stack.pop(), operand);
357                         case ISHR, LSHR ->
358                                 CoreOp.ashr(stack.pop(), operand);
359                         case IUSHR, LUSHR ->
360                                 CoreOp.lshr(stack.pop(), operand);
361                         case LCMP ->
362                                 CoreOp.invoke(LCMP, stack.pop(), operand);
363                         case FCMPL, FCMPG ->
364                                 CoreOp.invoke(FCMP, stack.pop(), operand);
365                         case DCMPL, DCMPG ->
366                                 CoreOp.invoke(DCMP, stack.pop(), operand);
367                         default ->
368                             throw new IllegalArgumentException("Unsupported operator opcode: " + inst.opcode());
369                     }));
370                 }
371                 case FieldInstruction inst -> {
372                         FieldRef fd = FieldRef.field(
373                                 JavaType.type(inst.owner().asSymbol()),
374                                 inst.name().stringValue(),
375                                 JavaType.type(inst.typeSymbol()));
376                         switch (inst.opcode()) {
377                             case GETFIELD ->
378                                 stack.push(op(CoreOp.fieldLoad(fd, stack.pop())));
379                             case GETSTATIC ->
380                                 stack.push(op(CoreOp.fieldLoad(fd)));
381                             case PUTFIELD -> {
382                                 Value value = stack.pop();
383                                 op(CoreOp.fieldStore(fd, stack.pop(), value));
384                             }
385                             case PUTSTATIC ->
386                                 op(CoreOp.fieldStore(fd, stack.pop()));
387                             default ->
388                                 throw new IllegalArgumentException("Unsupported field opcode: " + inst.opcode());
389                         }
390                 }
391                 case ArrayStoreInstruction _ -> {
392                     Value value = stack.pop();
393                     Value index = stack.pop();
394                     op(CoreOp.arrayStoreOp(stack.pop(), index, value));
395                 }
396                 case ArrayLoadInstruction ali -> {
397                     Value index = stack.pop();
398                     Value array = stack.pop();
399                     if (array.type() instanceof UnresolvedType) {
400                         stack.push(op(CoreOp.arrayLoadOp(array, index, switch (ali.typeKind()) {
401                             case BYTE -> UnresolvedType.unresolvedInt(); // @@@ Create UnresolvedType.unresolvedByteOrBoolean();
402                             case CHAR -> JavaType.CHAR;
403                             case DOUBLE -> JavaType.DOUBLE;
404                             case FLOAT -> JavaType.FLOAT;
405                             case INT -> JavaType.INT;
406                             case LONG -> JavaType.LONG;
407                             case SHORT -> JavaType.SHORT;
408                             case REFERENCE ->  UnresolvedType.unresolvedRef();
409                             case BOOLEAN, VOID -> throw new IllegalArgumentException("Unexpected array load instruction type");
410                         })));
411                     } else {
412                         stack.push(op(CoreOp.arrayLoadOp(array, index)));
413                     }
414                 }
415                 case InvokeInstruction inst -> {
416                     FunctionType mType = MethodRef.ofNominalDescriptor(inst.typeSymbol());
417                     List<Value> operands = new ArrayList<>();
418                     for (var _ : mType.parameterTypes()) {
419                         operands.add(stack.pop());
420                     }
421                     MethodRef mDesc = MethodRef.method(
422                             JavaType.type(inst.owner().asSymbol()),
423                             inst.name().stringValue(),
424                             mType);
425                     Op.Result result = switch (inst.opcode()) {
426                         case INVOKEVIRTUAL, INVOKEINTERFACE -> {
427                             operands.add(stack.pop());
428                             yield op(CoreOp.invoke(CoreOp.InvokeOp.InvokeKind.INSTANCE, false,
429                                     mDesc.type().returnType(), mDesc, operands.reversed()));
430                         }
431                         case INVOKESTATIC ->
432                                 op(CoreOp.invoke(CoreOp.InvokeOp.InvokeKind.STATIC, false,
433                                         mDesc.type().returnType(), mDesc, operands.reversed()));
434                         case INVOKESPECIAL -> {
435                             if (inst.owner().asSymbol().equals(newStack.peek()) && inst.name().equalsString(ConstantDescs.INIT_NAME)) {
436                                 newStack.pop();
437                                 yield op(CoreOp._new(
438                                         FunctionType.functionType(
439                                                 mDesc.refType(),
440                                                 mType.parameterTypes()),
441                                         operands.reversed()));
442                             } else {
443                                 operands.add(stack.pop());
444                                 yield op(CoreOp.invoke(CoreOp.InvokeOp.InvokeKind.SUPER, false,
445                                         mDesc.type().returnType(), mDesc, operands.reversed()));
446                             }
447                         }
448                         default ->
449                             throw new IllegalArgumentException("Unsupported invocation opcode: " + inst.opcode());
450                     };
451                     if (!result.type().equals(JavaType.VOID)) {
452                         stack.push(result);
453                     }
454                 }
455                 case InvokeDynamicInstruction inst when inst.bootstrapMethod().kind() == DirectMethodHandleDesc.Kind.STATIC -> {
456                     DirectMethodHandleDesc bsm = inst.bootstrapMethod();
457                     ClassDesc bsmOwner = bsm.owner();
458                     if (bsmOwner.equals(CD_LambdaMetafactory)
459                         && inst.bootstrapArgs().get(0) instanceof MethodTypeDesc mtd
460                         && inst.bootstrapArgs().get(1) instanceof DirectMethodHandleDesc dmhd) {
461 
462                         var capturedValues = new Value[dmhd.invocationType().parameterCount() - mtd.parameterCount()];
463                         for (int ci = capturedValues.length - 1; ci >= 0; ci--) {
464                             capturedValues[ci] = stack.pop();
465                         }
466                         for (int ci = capturedValues.length; ci < inst.typeSymbol().parameterCount(); ci++) {
467                             stack.pop();
468                         }
469                         MethodTypeDesc mt = dmhd.invocationType();
470                         if (capturedValues.length > 0) {
471                             mt = mt.dropParameterTypes(0, capturedValues.length);
472                         }
473                         FunctionType lambdaFunc = FunctionType.functionType(JavaType.type(mt.returnType()),
474                                                                             mt.parameterList().stream().map(JavaType::type).toList());
475                         CoreOp.LambdaOp.Builder lambda = CoreOp.lambda(currentBlock.parentBody(),
476                                                                        lambdaFunc,
477                                                                        JavaType.type(inst.typeSymbol().returnType()));
478                         if (dmhd.methodName().startsWith("lambda$") && dmhd.owner().equals(classModel.thisClass().asSymbol())) {
479                             // inline lambda impl method
480                             MethodModel implMethod = classModel.methods().stream().filter(m -> m.methodName().equalsString(dmhd.methodName())).findFirst().orElseThrow();
481                             stack.push(op(lambda.body(eb -> new BytecodeLift(eb,
482                                                            classModel,
483                                                            implMethod.code().orElseThrow(),
484                                                            capturedValues).liftBody())));
485                         } else {
486                             // lambda call to a MH
487                             stack.push(op(lambda.body(eb -> {
488                                 Op.Result ret = eb.op(CoreOp.invoke(
489                                         MethodRef.method(JavaType.type(dmhd.owner()),
490                                                          dmhd.methodName(),
491                                                          lambdaFunc.returnType(),
492                                                          lambdaFunc.parameterTypes()),
493                                         Stream.concat(Arrays.stream(capturedValues), eb.parameters().stream()).toArray(Value[]::new)));
494                                 eb.op(ret.type().equals(JavaType.VOID) ? CoreOp._return() : CoreOp._return(ret));
495                             })));
496                         }
497                     } else if (bsmOwner.equals(CD_StringConcatFactory)) {
498                         int argsCount = inst.typeSymbol().parameterCount();
499                         Deque<Value> args = new ArrayDeque<>(argsCount);
500                         for (int ai = 0; ai < argsCount; ai++) {
501                             args.push(stack.pop());
502                         }
503                         Value res = null;
504                         if (bsm.methodName().equals("makeConcat")) {
505                             for (Value argVal : args) {
506                                 res = res == null ? argVal : op(CoreOp.concat(res, argVal));
507                             }
508                         } else {
509                             assert bsm.methodName().equals("makeConcatWithConstants");
510                             var bsmArgs = inst.bootstrapArgs();
511                             String recipe = (String)(bsmArgs.getFirst());
512                             int bsmArg = 1;
513                             for (int ri = 0; ri < recipe.length(); ri++) {
514                                 Value argVal = switch (recipe.charAt(ri)) {
515                                     case '\u0001' -> args.pop();
516                                     case '\u0002' -> liftConstant(bsmArgs.get(bsmArg++));
517                                     default -> {
518                                         char c;
519                                         int start = ri;
520                                         while (ri < recipe.length() && (c = recipe.charAt(ri)) != '\u0001' && c != '\u0002') ri++;
521                                         yield liftConstant(recipe.substring(start, ri--));
522                                     }
523                                 };
524                                 res = res == null ? argVal : op(CoreOp.concat(res, argVal));
525                             }
526                         }
527                         if (res != null) stack.push(res);
528                     } else {
529                         MethodTypeDesc mtd = inst.typeSymbol();
530 
531                         //bootstrap
532                         MethodTypeDesc bsmDesc = bsm.invocationType();
533                         MethodRef bsmRef = MethodRef.method(JavaType.type(bsmOwner),
534                                                             bsm.methodName(),
535                                                             JavaType.type(bsmDesc.returnType()),
536                                                             bsmDesc.parameterList().stream().map(JavaType::type).toArray(TypeElement[]::new));
537 
538                         Value[] bootstrapArgs = liftBootstrapArgs(bsmDesc, inst.name().toString(), mtd, inst.bootstrapArgs());
539                         Value methodHandle = op(CoreOp.invoke(MethodRef.method(CallSite.class, "dynamicInvoker", MethodHandle.class),
540                                                     op(CoreOp.invoke(JavaType.type(ConstantDescs.CD_CallSite), bsmRef, bootstrapArgs))));
541 
542                         //invocation
543                         List<Value> operands = new ArrayList<>();
544                         for (int c = 0; c < mtd.parameterCount(); c++) {
545                             operands.add(stack.pop());
546                         }
547                         operands.add(methodHandle);
548                         MethodRef mDesc = MethodRef.method(JavaType.type(ConstantDescs.CD_MethodHandle),
549                                                            "invokeExact",
550                                                            MethodRef.ofNominalDescriptor(mtd));
551                         Op.Result result = op(CoreOp.invoke(mDesc, operands.reversed()));
552                         if (!result.type().equals(JavaType.VOID)) {
553                             stack.push(result);
554                         }
555                     }
556                 }
557                 case NewObjectInstruction inst -> {
558                     // Skip over this and the dup to process the invoke special
559                     if (i + 2 < elements.size() - 1
560                             && elements.get(i + 1) instanceof StackInstruction dup
561                             && dup.opcode() == Opcode.DUP) {
562                         i++;
563                         newStack.push(inst.className().asSymbol());
564                     } else {
565                         throw new UnsupportedOperationException("New must be followed by dup");
566                     }
567                 }
568                 case NewPrimitiveArrayInstruction inst -> {
569                     stack.push(op(CoreOp.newArray(
570                             switch (inst.typeKind()) {
571                                 case BOOLEAN -> JavaType.BOOLEAN_ARRAY;
572                                 case BYTE -> JavaType.BYTE_ARRAY;
573                                 case CHAR -> JavaType.CHAR_ARRAY;
574                                 case DOUBLE -> JavaType.DOUBLE_ARRAY;
575                                 case FLOAT -> JavaType.FLOAT_ARRAY;
576                                 case INT -> JavaType.INT_ARRAY;
577                                 case LONG -> JavaType.LONG_ARRAY;
578                                 case SHORT -> JavaType.SHORT_ARRAY;
579                                 default ->
580                                         throw new UnsupportedOperationException("Unsupported new primitive array type: " + inst.typeKind());
581                             },
582                             stack.pop())));
583                 }
584                 case NewReferenceArrayInstruction inst -> {
585                     stack.push(op(CoreOp.newArray(
586                             JavaType.type(inst.componentType().asSymbol().arrayType()),
587                             stack.pop())));
588                 }
589                 case NewMultiArrayInstruction inst -> {
590                     stack.push(op(CoreOp._new(
591                             FunctionType.functionType(
592                                     JavaType.type(inst.arrayType().asSymbol()),
593                                     Collections.nCopies(inst.dimensions(), JavaType.INT)),
594                             IntStream.range(0, inst.dimensions()).mapToObj(_ -> stack.pop()).toList().reversed())));
595                 }
596                 case TypeCheckInstruction inst when inst.opcode() == Opcode.CHECKCAST -> {
597                     stack.push(op(CoreOp.cast(JavaType.type(inst.type().asSymbol()), stack.pop())));
598                 }
599                 case TypeCheckInstruction inst -> {
600                     stack.push(op(CoreOp.instanceOf(JavaType.type(inst.type().asSymbol()), stack.pop())));
601                 }
602                 case StackInstruction inst -> {
603                     switch (inst.opcode()) {
604                         case POP -> {
605                             stack.pop();
606                         }
607                         case POP2 -> {
608                             if (isCategory1(stack.pop())) {
609                                 stack.pop();
610                             }
611                         }
612                         case DUP -> {
613                             stack.push(stack.peek());
614                         }
615                         case DUP_X1 -> {
616                             var value1 = stack.pop();
617                             var value2 = stack.pop();
618                             stack.push(value1);
619                             stack.push(value2);
620                             stack.push(value1);
621                         }
622                         case DUP_X2 -> {
623                             var value1 = stack.pop();
624                             var value2 = stack.pop();
625                             if (isCategory1(value2)) {
626                                 var value3 = stack.pop();
627                                 stack.push(value1);
628                                 stack.push(value3);
629                             } else {
630                                 stack.push(value1);
631                             }
632                             stack.push(value2);
633                             stack.push(value1);
634                         }
635                         case DUP2 -> {
636                             var value1 = stack.peek();
637                             if (isCategory1(value1)) {
638                                 stack.pop();
639                                 var value2 = stack.peek();
640                                 stack.push(value1);
641                                 stack.push(value2);
642                             }
643                             stack.push(value1);
644                         }
645                         case DUP2_X1 -> {
646                             var value1 = stack.pop();
647                             var value2 = stack.pop();
648                             if (isCategory1(value1)) {
649                                 var value3 = stack.pop();
650                                 stack.push(value2);
651                                 stack.push(value1);
652                                 stack.push(value3);
653                             } else {
654                                 stack.push(value1);
655                             }
656                             stack.push(value2);
657                             stack.push(value1);
658                         }
659                         case DUP2_X2 -> {
660                             var value1 = stack.pop();
661                             var value2 = stack.pop();
662                             if (isCategory1(value1)) {
663                                 var value3 = stack.pop();
664                                 if (isCategory1(value3)) {
665                                     var value4 = stack.pop();
666                                     stack.push(value2);
667                                     stack.push(value1);
668                                     stack.push(value4);
669                                 } else {
670                                     stack.push(value2);
671                                     stack.push(value1);
672                                 }
673                                 stack.push(value3);
674                             } else {
675                                 if (isCategory1(value2)) {
676                                     var value3 = stack.pop();
677                                     stack.push(value1);
678                                     stack.push(value3);
679                                 } else {
680                                     stack.push(value1);
681                                 }
682                             }
683                             stack.push(value2);
684                             stack.push(value1);
685                         }
686                         case SWAP -> {
687                             var value1 = stack.pop();
688                             var value2 = stack.pop();
689                             stack.push(value1);
690                             stack.push(value2);
691                         }
692                         default ->
693                             throw new UnsupportedOperationException("Unsupported stack instruction: " + inst);
694                     }
695                 }
696                 case MonitorInstruction inst -> {
697                     var monitor = stack.pop();
698                     switch (inst.opcode()) {
699                         case MONITORENTER -> op(CoreOp.monitorEnter(monitor));
700                         case MONITOREXIT -> op(CoreOp.monitorExit(monitor));
701                         default ->
702                                 throw new UnsupportedOperationException("Unsupported stack instruction: " + inst);
703                     }
704                 }
705                 case NopInstruction _ -> {}
706                 case PseudoInstruction _ -> {}
707                 case Instruction inst ->
708                     throw new UnsupportedOperationException("Unsupported instruction: " + inst.opcode().name());
709                 default ->
710                     throw new UnsupportedOperationException("Unsupported code element: " + elements.get(i));
711             }
712         }
713         assert newStack.isEmpty();
714     }
715 
716     private Op.Result liftConstantsIntoArray(TypeElement arrayType, Object... constants) {
717         Op.Result array = op(CoreOp.newArray(arrayType, liftConstant(constants.length)));
718         for (int i = 0; i < constants.length; i++) {
719             op(CoreOp.arrayStoreOp(array, liftConstant(i), liftConstant(constants[i])));
720         }
721         return array;
722     }
723 
724     private Op.Result liftDefaultValue(ClassDesc type) {
725         return liftConstant(switch (TypeKind.from(type)) {
726             case BOOLEAN -> false;
727             case BYTE -> (byte)0;
728             case CHAR -> (char)0;
729             case DOUBLE -> 0d;
730             case FLOAT -> 0f;
731             case INT -> 0;
732             case LONG -> 0l;
733             case REFERENCE -> null;
734             case SHORT -> (short)0;
735             default -> throw new IllegalStateException("Invalid type " + type.displayName());
736         });
737     }
738 
739     private Op.Result liftConstant(Object c) {
740         return switch (c) {
741             case null -> op(CoreOp.constant(UnresolvedType.unresolvedRef(), null));
742             case ClassDesc cd -> op(CoreOp.constant(JavaType.J_L_CLASS, JavaType.type(cd)));
743             case Double d -> op(CoreOp.constant(JavaType.DOUBLE, d));
744             case Float f -> op(CoreOp.constant(JavaType.FLOAT, f));
745             case Integer ii -> op(CoreOp.constant(UnresolvedType.unresolvedInt(), ii));
746             case Long l -> op(CoreOp.constant(JavaType.LONG, l));
747             case String s -> op(CoreOp.constant(JavaType.J_L_STRING, s));
748             case DirectMethodHandleDesc dmh -> {
749                 Op.Result lookup = op(CoreOp.invoke(LOOKUP));
750                 Op.Result owner = liftConstant(dmh.owner());
751                 Op.Result name = liftConstant(dmh.methodName());
752                 MethodTypeDesc invDesc = dmh.invocationType();
753                 yield op(switch (dmh.kind()) {
754                     case STATIC, INTERFACE_STATIC  ->
755                         CoreOp.invoke(FIND_STATIC, lookup, owner, name, liftConstant(invDesc));
756                     case VIRTUAL, INTERFACE_VIRTUAL ->
757                         CoreOp.invoke(FIND_VIRTUAL, lookup, owner, name, liftConstant(invDesc.dropParameterTypes(0, 1)));
758                     case SPECIAL, INTERFACE_SPECIAL ->
759                         //CoreOp.invoke(MethodRef.method(e), "findSpecial", owner, name, liftConstant(invDesc.dropParameterTypes(0, 1)), lookup.lookupClass());
760                         throw new UnsupportedOperationException(dmh.toString());
761                     case CONSTRUCTOR       ->
762                         CoreOp.invoke(FIND_CONSTRUCTOR, lookup, owner, liftConstant(invDesc.changeReturnType(ConstantDescs.CD_Void)));
763                     case GETTER            ->
764                         CoreOp.invoke(FIND_GETTER, lookup, owner, name, liftConstant(invDesc.returnType()));
765                     case STATIC_GETTER     ->
766                         CoreOp.invoke(FIND_STATIC_GETTER, lookup, owner, name, liftConstant(invDesc.returnType()));
767                     case SETTER            ->
768                         CoreOp.invoke(FIND_SETTER, lookup, owner, name, liftConstant(invDesc.parameterType(1)));
769                     case STATIC_SETTER     ->
770                         CoreOp.invoke(FIND_STATIC_SETTER, lookup, owner, name, liftConstant(invDesc.parameterType(0)));
771                 });
772             }
773             case MethodTypeDesc mt -> op(switch (mt.parameterCount()) {
774                 case 0 -> CoreOp.invoke(METHOD_TYPE_0, liftConstant(mt.returnType()));
775                 case 1 -> CoreOp.invoke(METHOD_TYPE_1, liftConstant(mt.returnType()), liftConstant(mt.parameterType(0)));
776                 default -> CoreOp.invoke(METHOD_TYPE_L, liftConstant(mt.returnType()), liftConstantsIntoArray(CLASS_ARRAY, (Object[])mt.parameterArray()));
777             });
778             case DynamicConstantDesc<?> v when v.bootstrapMethod().owner().equals(ConstantDescs.CD_ConstantBootstraps)
779                                          && v.bootstrapMethod().methodName().equals("nullConstant")
780                     -> {
781                 c = null;
782                 yield liftConstant(null);
783             }
784             case DynamicConstantDesc<?> dcd -> {
785                 DirectMethodHandleDesc bsm = dcd.bootstrapMethod();
786                 MethodTypeDesc bsmDesc = bsm.invocationType();
787                 Value[] bootstrapArgs = liftBootstrapArgs(bsmDesc, dcd.constantName(), dcd.constantType(), dcd.bootstrapArgsList());
788                 MethodRef bsmRef = MethodRef.method(JavaType.type(bsm.owner()),
789                                                     bsm.methodName(),
790                                                     JavaType.type(bsmDesc.returnType()),
791                                                     bsmDesc.parameterList().stream().map(JavaType::type).toArray(TypeElement[]::new));
792                 yield op(CoreOp.invoke(bsmRef, bootstrapArgs));
793             }
794             case Boolean b -> op(CoreOp.constant(JavaType.BOOLEAN, b));
795             case Byte b -> op(CoreOp.constant(JavaType.BYTE, b));
796             case Short s -> op(CoreOp.constant(JavaType.SHORT, s));
797             case Character ch -> op(CoreOp.constant(JavaType.CHAR, ch));
798             default -> throw new UnsupportedOperationException(c.getClass().toString());
799         };
800     }
801 
802     private Value[] liftBootstrapArgs(MethodTypeDesc bsmDesc, String name, ConstantDesc desc, List<ConstantDesc> bsmArgs) {
803         Value[] bootstrapArgs = new Value[bsmDesc.parameterCount()];
804         bootstrapArgs[0] = op(CoreOp.invoke(LOOKUP));
805         bootstrapArgs[1] = liftConstant(name);
806         bootstrapArgs[2] = liftConstant(desc);
807         ClassDesc lastArgType = bsmDesc.parameterType(bsmDesc.parameterCount() - 1);
808         if (lastArgType.isArray()) {
809             for (int ai = 0; ai < bootstrapArgs.length - 4; ai++) {
810                 bootstrapArgs[ai + 3] = liftConstant(bsmArgs.get(ai));
811             }
812             // Vararg tail of the bootstrap method parameters
813             bootstrapArgs[bootstrapArgs.length - 1] =
814                     liftConstantsIntoArray(JavaType.type(lastArgType),
815                                            bsmArgs.subList(bootstrapArgs.length - 4, bsmArgs.size()).toArray());
816         } else {
817             for (int ai = 0; ai < bootstrapArgs.length - 3; ai++) {
818                 bootstrapArgs[ai + 3] = liftConstant(bsmArgs.get(ai));
819             }
820         }
821         return bootstrapArgs;
822     }
823 
824     private void liftSwitch(Label defaultTarget, List<SwitchCase> cases) {
825         Value v = stack.pop();
826         if (!valueType(v).equals(PrimitiveType.INT)) {
827             v = op(CoreOp.conv(PrimitiveType.INT, v));
828         }
829         SwitchCase last = cases.getLast();
830         Block.Builder def = targetBlockForBranch(defaultTarget);
831         for (SwitchCase sc : cases) {
832             if (sc == last) {
833                 op(CoreOp.conditionalBranch(
834                         op(CoreOp.eq(v, liftConstant(sc.caseValue()))),
835                         successorWithStack(targetBlockForBranch(sc.target())),
836                         successorWithStack(def)));
837             } else {
838                 Block.Builder next = entryBlock.block();
839                 op(CoreOp.conditionalBranch(
840                         op(CoreOp.eq(v, liftConstant(sc.caseValue()))),
841                         successorWithStack(targetBlockForBranch(sc.target())),
842                         next.successor()));
843                 currentBlock = next;
844             }
845         }
846         endOfFlow();
847     }
848 
849     private Block.Builder newBlock(List<Block.Parameter> otherBlockParams) {
850         return entryBlock.block(otherBlockParams.stream().map(Block.Parameter::type).toList());
851     }
852 
853     private void endOfFlow() {
854         currentBlock = null;
855         // Flow discontinued, stack cleared to be ready for the next label target
856         stack.clear();
857     }
858 
859     private Block.Builder targetBlockForExceptionHandler(BitSet initialEreStack, int exceptionHandlerIndex) {
860         Block.Builder target = exceptionHandlerBlocks.get(exceptionHandlerIndex);
861         if (target == null) { // Avoid ConcurrentModificationException
862             Label ehLabel = exceptionHandlers.get(exceptionHandlerIndex);
863             target = transitionBlockForTarget(initialEreStack, exceptionHandlersMap.get(ehLabel), blockMap.get(ehLabel), exceptionHandlerIndex);
864             exceptionHandlerBlocks.put(exceptionHandlerIndex, target);
865         }
866         return target;
867     }
868 
869     private Block.Builder targetBlockForBranch(Label targetLabel) {
870         return transitionBlockForTarget(actualEreStack, exceptionHandlersMap.get(targetLabel), blockMap.get(targetLabel), -1);
871     }
872 
873     private Block.Builder transitionBlockForTarget(BitSet initialEreStack, BitSet targetEreStack, Block.Builder targetBlock, int targetExceptionHandlerIndex) {
874         if (targetBlock == null) return null;
875         Block.Builder transitionBlock = newBlock(targetBlock.parameters());
876         ereTransit(initialEreStack, targetEreStack, transitionBlock, targetBlock, transitionBlock.parameters(), targetExceptionHandlerIndex);
877         return transitionBlock;
878     }
879 
880     record EreT(boolean enter, int ehi) {}
881 
882     private void ereTransit(BitSet initialEreStack, BitSet targetEreStack, Block.Builder initialBlock, Block.Builder targetBlock, List<? extends Value> values, int targetExceptionHandlerIndex) {
883         List<EreT> transits = new ArrayList<>();
884         BitSet ereStack = (BitSet)initialEreStack.clone();
885         ereStack.andNot(targetEreStack);
886         // Split region exits by handler stack
887         for (int ehi = ereStack.previousSetBit(Integer.MAX_VALUE); ehi >= 0; ehi = ereStack.previousSetBit(ehi - 1)) {
888             transits.add(new EreT(false, ehi));
889         }
890         ereStack = (BitSet)targetEreStack.clone();
891         ereStack.andNot(initialEreStack);
892         // Split region enters by handler stack
893         for (int ehi = ereStack.nextSetBit(0); ehi >= 0; ehi = ereStack.nextSetBit(ehi + 1)) {
894             transits.add(new EreT(true, ehi));
895         }
896 
897         if (transits.isEmpty()) {
898             // Join with branch
899             initialBlock.op(CoreOp.branch(targetBlock.successor(values)));
900         } else {
901             // Insert ERE transitions
902             Block.Builder currentBlock = initialBlock;
903             ereStack = (BitSet)initialEreStack.clone();
904             for (int i = 0; i < transits.size() - 1; i++) {
905                 EreT t = transits.get(i);
906                 Block.Builder next = entryBlock.block();
907                 ereTransit(initialBlock, currentBlock, t.enter(), next, List.of(), t.ehi(), targetExceptionHandlerIndex, ereStack);
908                 currentBlock = next;
909                 ereStack.set(t.ehi(), t.enter());
910             }
911             EreT t = transits.getLast();
912             ereTransit(initialBlock, currentBlock, t.enter(), targetBlock, values, t.ehi(), targetExceptionHandlerIndex, ereStack);
913         }
914     }
915 
916     private void ereTransit(Block.Builder initialBlock, Block.Builder currentBlock, boolean enter, Block.Builder targetBlock, List<? extends Value> values, int ehi, int targetExceptionHandlerIndex, BitSet handlerEreStack) {
917         Block.Reference ref = targetBlock.successor(values);
918         Block.Reference catcher = (ehi == targetExceptionHandlerIndex
919                 ? initialBlock
920                 : targetBlockForExceptionHandler(handlerEreStack, ehi)).successor();
921         currentBlock.op(enter ? CoreOp.exceptionRegionEnter(ref, catcher) : CoreOp.exceptionRegionExit(ref, catcher));
922     }
923 
924     Block.Reference successorWithStack(Block.Builder next) {
925         return next.successor(stackValues(next));
926     }
927 
928     private List<Value> stackValues(Block.Builder limit) {
929         return stack.stream().limit(limit.parameters().size()).toList();
930     }
931 
932     private static TypeElement valueType(Value v) {
933         var t = v.type();
934         while (t instanceof VarType vt) t = vt.valueType();
935         return t;
936     }
937 
938     private static boolean isCategory1(Value v) {
939         TypeElement t = v.type();
940         return !t.equals(JavaType.LONG) && !t.equals(JavaType.DOUBLE);
941     }
942 }