1 /*
2 * Copyright (c) 2012, 2013, 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 java.lang.invoke;
27
28 import sun.invoke.util.VerifyAccess;
29 import static java.lang.invoke.LambdaForm.*;
30
31 import sun.invoke.util.Wrapper;
32
33 import java.io.*;
34 import java.util.*;
35
36 import jdk.internal.org.objectweb.asm.*;
37
38 import java.lang.reflect.*;
39 import static java.lang.invoke.MethodHandleStatics.*;
40 import static java.lang.invoke.MethodHandleNatives.Constants.*;
41 import static java.lang.invoke.LambdaForm.BasicType.*;
42 import sun.invoke.util.VerifyType;
43
44 /**
45 * Code generation backend for LambdaForm.
46 * <p>
47 * @author John Rose, JSR 292 EG
48 */
49 class InvokerBytecodeGenerator {
50 /** Define class names for convenience. */
51 private static final String MH = "java/lang/invoke/MethodHandle";
52 private static final String MHI = "java/lang/invoke/MethodHandleImpl";
53 private static final String LF = "java/lang/invoke/LambdaForm";
54 private static final String LFN = "java/lang/invoke/LambdaForm$Name";
55 private static final String CLS = "java/lang/Class";
56 private static final String OBJ = "java/lang/Object";
57 private static final String OBJARY = "[Ljava/lang/Object;";
58
59 private static final String LF_SIG = "L" + LF + ";";
60 private static final String LFN_SIG = "L" + LFN + ";";
61 private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";";
62 private static final String CLL_SIG = "(L" + CLS + ";L" + OBJ + ";)L" + OBJ + ";";
63
64 /** Name of its super class*/
65 private static final String superName = LF;
66
67 /** Name of new class */
68 private final String className;
69
70 /** Name of the source file (for stack trace printing). */
71 private final String sourceFile;
72
73 private final LambdaForm lambdaForm;
74 private final String invokerName;
75 private final MethodType invokerType;
76 private final int[] localsMap;
77
78 /** ASM bytecode generation. */
79 private ClassWriter cw;
80 private MethodVisitor mv;
81
82 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
83 private static final Class<?> HOST_CLASS = LambdaForm.class;
84
85 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
86 String className, String invokerName, MethodType invokerType) {
87 if (invokerName.contains(".")) {
88 int p = invokerName.indexOf(".");
89 className = invokerName.substring(0, p);
90 invokerName = invokerName.substring(p+1);
91 }
92 if (DUMP_CLASS_FILES) {
93 className = makeDumpableClassName(className);
94 }
95 this.className = superName + "$" + className;
96 this.sourceFile = "LambdaForm$" + className;
97 this.lambdaForm = lambdaForm;
98 this.invokerName = invokerName;
99 this.invokerType = invokerType;
100 this.localsMap = new int[localsMapSize];
101 }
102
103 private InvokerBytecodeGenerator(String className, String invokerName, MethodType invokerType) {
104 this(null, invokerType.parameterCount(),
105 className, invokerName, invokerType);
106 // Create an array to map name indexes to locals indexes.
107 for (int i = 0; i < localsMap.length; i++) {
108 localsMap[i] = invokerType.parameterSlotCount() - invokerType.parameterSlotDepth(i);
109 }
110 }
111
112 private InvokerBytecodeGenerator(String className, LambdaForm form, MethodType invokerType) {
113 this(form, form.names.length,
114 className, form.debugName, invokerType);
115 // Create an array to map name indexes to locals indexes.
116 Name[] names = form.names;
117 for (int i = 0, index = 0; i < localsMap.length; i++) {
118 localsMap[i] = index;
119 index += names[i].type.basicTypeSlots();
120 }
121 }
122
123
124 /** instance counters for dumped classes */
125 private final static HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS;
126 /** debugging flag for saving generated class files */
127 private final static File DUMP_CLASS_FILES_DIR;
128
129 static {
130 if (DUMP_CLASS_FILES) {
131 DUMP_CLASS_FILES_COUNTERS = new HashMap<>();
132 try {
133 File dumpDir = new File("DUMP_CLASS_FILES");
134 if (!dumpDir.exists()) {
135 dumpDir.mkdirs();
136 }
137 DUMP_CLASS_FILES_DIR = dumpDir;
138 System.out.println("Dumping class files to "+DUMP_CLASS_FILES_DIR+"/...");
139 } catch (Exception e) {
140 throw newInternalError(e);
141 }
142 } else {
143 DUMP_CLASS_FILES_COUNTERS = null;
144 DUMP_CLASS_FILES_DIR = null;
145 }
146 }
147
148 static void maybeDump(final String className, final byte[] classFile) {
149 if (DUMP_CLASS_FILES) {
150 System.out.println("dump: " + className);
151 java.security.AccessController.doPrivileged(
152 new java.security.PrivilegedAction<Void>() {
153 public Void run() {
154 try {
155 String dumpName = className;
156 //dumpName = dumpName.replace('/', '-');
157 File dumpFile = new File(DUMP_CLASS_FILES_DIR, dumpName+".class");
158 dumpFile.getParentFile().mkdirs();
159 FileOutputStream file = new FileOutputStream(dumpFile);
160 file.write(classFile);
161 file.close();
162 return null;
163 } catch (IOException ex) {
164 throw newInternalError(ex);
165 }
166 }
167 });
168 }
169
170 }
171
172 private static String makeDumpableClassName(String className) {
173 Integer ctr;
174 synchronized (DUMP_CLASS_FILES_COUNTERS) {
175 ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
176 if (ctr == null) ctr = 0;
177 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
178 }
179 String sfx = ctr.toString();
180 while (sfx.length() < 3)
181 sfx = "0"+sfx;
182 className += sfx;
183 return className;
184 }
185
186 class CpPatch {
187 final int index;
188 final String placeholder;
189 final Object value;
190 CpPatch(int index, String placeholder, Object value) {
191 this.index = index;
192 this.placeholder = placeholder;
193 this.value = value;
194 }
195 public String toString() {
196 return "CpPatch/index="+index+",placeholder="+placeholder+",value="+value;
197 }
198 }
199
200 Map<Object, CpPatch> cpPatches = new HashMap<>();
201
202 int cph = 0; // for counting constant placeholders
203
204 String constantPlaceholder(Object arg) {
205 String cpPlaceholder = "CONSTANT_PLACEHOLDER_" + cph++;
206 if (DUMP_CLASS_FILES) cpPlaceholder += " <<" + arg.toString() + ">>"; // debugging aid
207 if (cpPatches.containsKey(cpPlaceholder)) {
208 throw new InternalError("observed CP placeholder twice: " + cpPlaceholder);
209 }
210 // insert placeholder in CP and remember the patch
211 int index = cw.newConst((Object) cpPlaceholder); // TODO check if aready in the constant pool
212 cpPatches.put(cpPlaceholder, new CpPatch(index, cpPlaceholder, arg));
213 return cpPlaceholder;
214 }
215
216 Object[] cpPatches(byte[] classFile) {
217 int size = getConstantPoolSize(classFile);
218 Object[] res = new Object[size];
219 for (CpPatch p : cpPatches.values()) {
220 if (p.index >= size)
221 throw new InternalError("in cpool["+size+"]: "+p+"\n"+Arrays.toString(Arrays.copyOf(classFile, 20)));
222 res[p.index] = p.value;
223 }
224 return res;
225 }
226
227 /**
228 * Extract the number of constant pool entries from a given class file.
229 *
230 * @param classFile the bytes of the class file in question.
231 * @return the number of entries in the constant pool.
232 */
233 private static int getConstantPoolSize(byte[] classFile) {
234 // The first few bytes:
235 // u4 magic;
236 // u2 minor_version;
237 // u2 major_version;
238 // u2 constant_pool_count;
239 return ((classFile[8] & 0xFF) << 8) | (classFile[9] & 0xFF);
240 }
241
242 /**
243 * Extract the MemberName of a newly-defined method.
244 */
245 private MemberName loadMethod(byte[] classFile) {
246 Class<?> invokerClass = loadAndInitializeInvokerClass(classFile, cpPatches(classFile));
247 return resolveInvokerMember(invokerClass, invokerName, invokerType);
248 }
249
250 /**
251 * Define a given class as anonymous class in the runtime system.
252 */
253 private static Class<?> loadAndInitializeInvokerClass(byte[] classBytes, Object[] patches) {
254 Class<?> invokerClass = UNSAFE.defineAnonymousClass(HOST_CLASS, classBytes, patches);
255 UNSAFE.ensureClassInitialized(invokerClass); // Make sure the class is initialized; VM might complain.
256 return invokerClass;
257 }
258
259 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
260 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
261 //System.out.println("resolveInvokerMember => "+member);
262 //for (Method m : invokerClass.getDeclaredMethods()) System.out.println(" "+m);
263 try {
264 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member, HOST_CLASS, ReflectiveOperationException.class);
265 } catch (ReflectiveOperationException e) {
266 throw newInternalError(e);
267 }
268 //System.out.println("resolveInvokerMember => "+member);
269 return member;
270 }
271
272 /**
273 * Set up class file generation.
274 */
275 private void classFilePrologue() {
276 cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
277 cw.visit(Opcodes.V1_8, Opcodes.ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER, className, null, superName, null);
278 cw.visitSource(sourceFile, null);
279
280 String invokerDesc = invokerType.toMethodDescriptorString();
281 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null);
282 }
283
284 /**
285 * Tear down class file generation.
286 */
287 private void classFileEpilogue() {
288 mv.visitMaxs(0, 0);
289 mv.visitEnd();
290 }
291
292 /*
293 * Low-level emit helpers.
294 */
295 private void emitConst(Object con) {
296 if (con == null) {
297 mv.visitInsn(Opcodes.ACONST_NULL);
298 return;
299 }
300 if (con instanceof Integer) {
301 emitIconstInsn((int) con);
302 return;
303 }
304 if (con instanceof Long) {
305 long x = (long) con;
306 if (x == (short) x) {
307 emitIconstInsn((int) x);
308 mv.visitInsn(Opcodes.I2L);
309 return;
310 }
311 }
312 if (con instanceof Float) {
313 float x = (float) con;
314 if (x == (short) x) {
315 emitIconstInsn((int) x);
316 mv.visitInsn(Opcodes.I2F);
317 return;
318 }
319 }
320 if (con instanceof Double) {
321 double x = (double) con;
322 if (x == (short) x) {
323 emitIconstInsn((int) x);
324 mv.visitInsn(Opcodes.I2D);
325 return;
326 }
327 }
328 if (con instanceof Boolean) {
329 emitIconstInsn((boolean) con ? 1 : 0);
330 return;
331 }
332 // fall through:
333 mv.visitLdcInsn(con);
334 }
335
336 private void emitIconstInsn(int i) {
337 int opcode;
338 switch (i) {
339 case 0: opcode = Opcodes.ICONST_0; break;
340 case 1: opcode = Opcodes.ICONST_1; break;
341 case 2: opcode = Opcodes.ICONST_2; break;
342 case 3: opcode = Opcodes.ICONST_3; break;
343 case 4: opcode = Opcodes.ICONST_4; break;
344 case 5: opcode = Opcodes.ICONST_5; break;
345 default:
346 if (i == (byte) i) {
347 mv.visitIntInsn(Opcodes.BIPUSH, i & 0xFF);
348 } else if (i == (short) i) {
349 mv.visitIntInsn(Opcodes.SIPUSH, (char) i);
350 } else {
351 mv.visitLdcInsn(i);
352 }
353 return;
354 }
355 mv.visitInsn(opcode);
356 }
357
358 /*
359 * NOTE: These load/store methods use the localsMap to find the correct index!
360 */
361 private void emitLoadInsn(BasicType type, int index) {
362 int opcode = loadInsnOpcode(type);
363 mv.visitVarInsn(opcode, localsMap[index]);
364 }
365
366 private int loadInsnOpcode(BasicType type) throws InternalError {
367 int opcode;
368 switch (type) {
369 case I_TYPE: opcode = Opcodes.ILOAD; break;
370 case J_TYPE: opcode = Opcodes.LLOAD; break;
371 case F_TYPE: opcode = Opcodes.FLOAD; break;
372 case D_TYPE: opcode = Opcodes.DLOAD; break;
373 case L_TYPE: opcode = Opcodes.ALOAD; break;
374 default:
375 throw new InternalError("unknown type: " + type);
376 }
377 return opcode;
378 }
379 private void emitAloadInsn(int index) {
380 emitLoadInsn(L_TYPE, index);
381 }
382
383 private void emitStoreInsn(BasicType type, int index) {
384 int opcode = storeInsnOpcode(type);
385 mv.visitVarInsn(opcode, localsMap[index]);
386 }
387
388 private int storeInsnOpcode(BasicType type) throws InternalError {
389 int opcode;
390 switch (type) {
391 case I_TYPE: opcode = Opcodes.ISTORE; break;
392 case J_TYPE: opcode = Opcodes.LSTORE; break;
393 case F_TYPE: opcode = Opcodes.FSTORE; break;
394 case D_TYPE: opcode = Opcodes.DSTORE; break;
395 case L_TYPE: opcode = Opcodes.ASTORE; break;
396 default:
397 throw new InternalError("unknown type: " + type);
398 }
399 return opcode;
400 }
401 private void emitAstoreInsn(int index) {
402 emitStoreInsn(L_TYPE, index);
403 }
404
405 /**
406 * Emit a boxing call.
407 *
408 * @param wrapper primitive type class to box.
409 */
410 private void emitBoxing(Wrapper wrapper) {
411 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
412 String name = "valueOf";
413 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";";
414 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false);
415 }
416
417 /**
418 * Emit an unboxing call (plus preceding checkcast).
419 *
420 * @param wrapper wrapper type class to unbox.
421 */
422 private void emitUnboxing(Wrapper wrapper) {
423 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
424 String name = wrapper.primitiveSimpleName() + "Value";
425 String desc = "()" + wrapper.basicTypeChar();
426 mv.visitTypeInsn(Opcodes.CHECKCAST, owner);
427 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false);
428 }
429
430 /**
431 * Emit an implicit conversion.
432 *
433 * @param ptype type of value present on stack
434 * @param pclass type of value required on stack
435 */
436 private void emitImplicitConversion(BasicType ptype, Class<?> pclass) {
437 assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
438 if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
439 return; // nothing to do
440 switch (ptype) {
441 case L_TYPE:
442 if (VerifyType.isNullConversion(Object.class, pclass))
443 return;
444 if (isStaticallyNameable(pclass)) {
445 mv.visitTypeInsn(Opcodes.CHECKCAST, getInternalName(pclass));
446 } else {
447 mv.visitLdcInsn(constantPlaceholder(pclass));
448 mv.visitTypeInsn(Opcodes.CHECKCAST, CLS);
449 mv.visitInsn(Opcodes.SWAP);
450 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "castReference", CLL_SIG, false);
451 if (pclass.isArray())
452 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY);
453 }
454 return;
455 case I_TYPE:
456 if (!VerifyType.isNullConversion(int.class, pclass))
457 emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass));
458 return;
459 }
460 throw new InternalError("bad implicit conversion: tc="+ptype+": "+pclass);
461 }
462
463 /**
464 * Emits an actual return instruction conforming to the given return type.
465 */
466 private void emitReturnInsn(BasicType type) {
467 int opcode;
468 switch (type) {
469 case I_TYPE: opcode = Opcodes.IRETURN; break;
470 case J_TYPE: opcode = Opcodes.LRETURN; break;
471 case F_TYPE: opcode = Opcodes.FRETURN; break;
472 case D_TYPE: opcode = Opcodes.DRETURN; break;
473 case L_TYPE: opcode = Opcodes.ARETURN; break;
474 case V_TYPE: opcode = Opcodes.RETURN; break;
475 default:
476 throw new InternalError("unknown return type: " + type);
477 }
478 mv.visitInsn(opcode);
479 }
480
481 private static String getInternalName(Class<?> c) {
482 assert(VerifyAccess.isTypeVisible(c, Object.class));
483 return c.getName().replace('.', '/');
484 }
485
486 /**
487 * Generate customized bytecode for a given LambdaForm.
488 */
489 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
490 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
491 return g.loadMethod(g.generateCustomizedCodeBytes());
492 }
493
494 /**
495 * Generate an invoker method for the passed {@link LambdaForm}.
496 */
497 private byte[] generateCustomizedCodeBytes() {
498 classFilePrologue();
499
500 // Suppress this method in backtraces displayed to the user.
501 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Hidden;", true);
502
503 // Mark this method as a compiled LambdaForm
504 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Compiled;", true);
505
506 // Force inlining of this invoker method.
507 mv.visitAnnotation("Ljava/lang/invoke/ForceInline;", true);
508
509 // iterate over the form's names, generating bytecode instructions for each
510 // start iterating at the first name following the arguments
511 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
512 Name name = lambdaForm.names[i];
513 MemberName member = name.function.member();
514
515 if (isSelectAlternative(i)) {
516 emitSelectAlternative(name, lambdaForm.names[i + 1]);
517 i++; // skip MH.invokeBasic of the selectAlternative result
518 } else if (isGuardWithCatch(i)) {
519 emitGuardWithCatch(i);
520 i = i+2; // Jump to the end of GWC idiom
521 } else if (isStaticallyInvocable(member)) {
522 emitStaticInvoke(member, name);
523 } else {
524 emitInvoke(name);
525 }
526
527 // Update cached form name's info in case an intrinsic spanning multiple names was encountered.
528 name = lambdaForm.names[i];
529 member = name.function.member();
530
531 // store the result from evaluating to the target name in a local if required
532 // (if this is the last value, i.e., the one that is going to be returned,
533 // avoid store/load/return and just return)
534 if (i == lambdaForm.names.length - 1 && i == lambdaForm.result) {
535 // return value - do nothing
536 } else if (name.type != V_TYPE) {
537 // non-void: actually assign
538 emitStoreInsn(name.type, name.index());
539 }
540 }
541
542 // return statement
543 emitReturn();
544
545 classFileEpilogue();
546 bogusMethod(lambdaForm);
547
548 final byte[] classFile = cw.toByteArray();
549 maybeDump(className, classFile);
550 return classFile;
551 }
552
553 /**
554 * Emit an invoke for the given name.
555 */
556 void emitInvoke(Name name) {
557 if (true) {
558 // push receiver
559 MethodHandle target = name.function.resolvedHandle;
560 assert(target != null) : name.exprString();
561 mv.visitLdcInsn(constantPlaceholder(target));
562 mv.visitTypeInsn(Opcodes.CHECKCAST, MH);
563 } else {
564 // load receiver
565 emitAloadInsn(0);
566 mv.visitTypeInsn(Opcodes.CHECKCAST, MH);
567 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG);
568 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG);
569 // TODO more to come
570 }
571
572 // push arguments
573 for (int i = 0; i < name.arguments.length; i++) {
574 emitPushArgument(name, i);
575 }
576
577 // invocation
578 MethodType type = name.function.methodType();
579 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
580 }
581
582 static private Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
583 // Sample classes from each package we are willing to bind to statically:
584 java.lang.Object.class,
585 java.util.Arrays.class,
586 sun.misc.Unsafe.class
587 //MethodHandle.class already covered
588 };
589
590 static boolean isStaticallyInvocable(MemberName member) {
591 if (member == null) return false;
592 if (member.isConstructor()) return false;
593 Class<?> cls = member.getDeclaringClass();
594 if (cls.isArray() || cls.isPrimitive())
595 return false; // FIXME
596 if (cls.isAnonymousClass() || cls.isLocalClass())
597 return false; // inner class of some sort
598 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
599 return false; // not on BCP
600 MethodType mtype = member.getMethodOrFieldType();
601 if (!isStaticallyNameable(mtype.returnType()))
602 return false;
603 for (Class<?> ptype : mtype.parameterArray())
604 if (!isStaticallyNameable(ptype))
605 return false;
606 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
607 return true; // in java.lang.invoke package
608 if (member.isPublic() && isStaticallyNameable(cls))
609 return true;
610 return false;
611 }
612
613 static boolean isStaticallyNameable(Class<?> cls) {
614 while (cls.isArray())
615 cls = cls.getComponentType();
616 if (cls.isPrimitive())
617 return true; // int[].class, for example
618 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
619 if (cls.getClassLoader() != Object.class.getClassLoader())
620 return false;
621 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
622 return true;
623 if (!Modifier.isPublic(cls.getModifiers()))
624 return false;
625 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
626 if (VerifyAccess.isSamePackage(pkgcls, cls))
627 return true;
628 }
629 return false;
630 }
631
632 /**
633 * Emit an invoke for the given name, using the MemberName directly.
634 */
635 void emitStaticInvoke(MemberName member, Name name) {
636 assert(member.equals(name.function.member()));
637 String cname = getInternalName(member.getDeclaringClass());
638 String mname = member.getName();
639 String mtype;
640 byte refKind = member.getReferenceKind();
641 if (refKind == REF_invokeSpecial) {
642 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
643 assert(member.canBeStaticallyBound()) : member;
644 refKind = REF_invokeVirtual;
645 }
646
647 if (member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual) {
648 // Methods from Object declared in an interface can be resolved by JVM to invokevirtual kind.
649 // Need to convert it back to invokeinterface to pass verification and make the invocation works as expected.
650 refKind = REF_invokeInterface;
651 }
652
653 // push arguments
654 for (int i = 0; i < name.arguments.length; i++) {
655 emitPushArgument(name, i);
656 }
657
658 // invocation
659 if (member.isMethod()) {
660 mtype = member.getMethodType().toMethodDescriptorString();
661 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype,
662 member.getDeclaringClass().isInterface());
663 } else {
664 mtype = MethodType.toFieldDescriptorString(member.getFieldType());
665 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype);
666 }
667 }
668 int refKindOpcode(byte refKind) {
669 switch (refKind) {
670 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL;
671 case REF_invokeStatic: return Opcodes.INVOKESTATIC;
672 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL;
673 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE;
674 case REF_getField: return Opcodes.GETFIELD;
675 case REF_putField: return Opcodes.PUTFIELD;
676 case REF_getStatic: return Opcodes.GETSTATIC;
677 case REF_putStatic: return Opcodes.PUTSTATIC;
678 }
679 throw new InternalError("refKind="+refKind);
680 }
681
682 /**
683 * Check if MemberName is a call to a method named {@code name} in class {@code declaredClass}.
684 */
685 private boolean memberRefersTo(MemberName member, Class<?> declaringClass, String name) {
686 return member != null &&
687 member.getDeclaringClass() == declaringClass &&
688 member.getName().equals(name);
689 }
690 private boolean nameRefersTo(Name name, Class<?> declaringClass, String methodName) {
691 return name.function != null &&
692 memberRefersTo(name.function.member(), declaringClass, methodName);
693 }
694
695 /**
696 * Check if MemberName is a call to MethodHandle.invokeBasic.
697 */
698 private boolean isInvokeBasic(Name name) {
699 if (name.function == null)
700 return false;
701 if (name.arguments.length < 1)
702 return false; // must have MH argument
703 MemberName member = name.function.member();
704 return memberRefersTo(member, MethodHandle.class, "invokeBasic") &&
705 !member.isPublic() && !member.isStatic();
706 }
707
708 /**
709 * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
710 */
711 private boolean isSelectAlternative(int pos) {
712 // selectAlternative idiom:
713 // t_{n}:L=MethodHandleImpl.selectAlternative(...)
714 // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
715 if (pos+1 >= lambdaForm.names.length) return false;
716 Name name0 = lambdaForm.names[pos];
717 Name name1 = lambdaForm.names[pos+1];
718 return nameRefersTo(name0, MethodHandleImpl.class, "selectAlternative") &&
719 isInvokeBasic(name1) &&
720 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
721 lambdaForm.lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
722 }
723
724 /**
725 * Check if i-th name is a start of GuardWithCatch idiom.
726 */
727 private boolean isGuardWithCatch(int pos) {
728 // GuardWithCatch idiom:
729 // t_{n}:L=MethodHandle.invokeBasic(...)
730 // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
731 // t_{n+2}:?=MethodHandle.invokeBasic(t_{n+1})
732 if (pos+2 >= lambdaForm.names.length) return false;
733 Name name0 = lambdaForm.names[pos];
734 Name name1 = lambdaForm.names[pos+1];
735 Name name2 = lambdaForm.names[pos+2];
736 return nameRefersTo(name1, MethodHandleImpl.class, "guardWithCatch") &&
737 isInvokeBasic(name0) &&
738 isInvokeBasic(name2) &&
739 name1.lastUseIndex(name0) == 3 && // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
740 lambdaForm.lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
741 name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(t_{n+1})
742 lambdaForm.lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
743 }
744
745 /**
746 * Emit bytecode for the selectAlternative idiom.
747 *
748 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
749 * <blockquote><pre>{@code
750 * Lambda(a0:L,a1:I)=>{
751 * t2:I=foo.test(a1:I);
752 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
753 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
754 * }</pre></blockquote>
755 */
756 private void emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) {
757 Name receiver = (Name) invokeBasicName.arguments[0];
758
759 Label L_fallback = new Label();
760 Label L_done = new Label();
761
762 // load test result
763 emitPushArgument(selectAlternativeName, 0);
764 mv.visitInsn(Opcodes.ICONST_1);
765
766 // if_icmpne L_fallback
767 mv.visitJumpInsn(Opcodes.IF_ICMPNE, L_fallback);
768
769 // invoke selectAlternativeName.arguments[1]
770 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative
771 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
772 emitInvoke(invokeBasicName);
773
774 // goto L_done
775 mv.visitJumpInsn(Opcodes.GOTO, L_done);
776
777 // L_fallback:
778 mv.visitLabel(L_fallback);
779
780 // invoke selectAlternativeName.arguments[2]
781 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative
782 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
783 emitInvoke(invokeBasicName);
784
785 // L_done:
786 mv.visitLabel(L_done);
787 }
788
789 /**
790 * Emit bytecode for the guardWithCatch idiom.
791 *
792 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
793 * <blockquote><pre>{@code
794 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
795 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
796 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
797 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
798 * }</pre></blockquote>
799 *
800 * It is compiled into bytecode equivalent of the following code:
801 * <blockquote><pre>{@code
802 * try {
803 * return a1.invokeBasic(a6, a7);
804 * } catch (Throwable e) {
805 * if (!a2.isInstance(e)) throw e;
806 * return a3.invokeBasic(ex, a6, a7);
807 * }}
808 */
809 private void emitGuardWithCatch(int pos) {
810 Name args = lambdaForm.names[pos];
811 Name invoker = lambdaForm.names[pos+1];
812 Name result = lambdaForm.names[pos+2];
813
814 Label L_startBlock = new Label();
815 Label L_endBlock = new Label();
816 Label L_handler = new Label();
817 Label L_done = new Label();
818
819 Class<?> returnType = result.function.resolvedHandle.type().returnType();
820 MethodType type = args.function.resolvedHandle.type()
821 .dropParameterTypes(0,1)
822 .changeReturnType(returnType);
823
824 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable");
825
826 // Normal case
827 mv.visitLabel(L_startBlock);
828 // load target
829 emitPushArgument(invoker, 0);
830 emitPushArguments(args, 1); // skip 1st argument: method handle
831 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
832 mv.visitLabel(L_endBlock);
833 mv.visitJumpInsn(Opcodes.GOTO, L_done);
834
835 // Exceptional case
836 mv.visitLabel(L_handler);
837
838 // Check exception's type
839 mv.visitInsn(Opcodes.DUP);
840 // load exception class
841 emitPushArgument(invoker, 1);
842 mv.visitInsn(Opcodes.SWAP);
843 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false);
844 Label L_rethrow = new Label();
845 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow);
846
847 // Invoke catcher
848 // load catcher
849 emitPushArgument(invoker, 2);
850 mv.visitInsn(Opcodes.SWAP);
851 emitPushArguments(args, 1); // skip 1st argument: method handle
852 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
853 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false);
854 mv.visitJumpInsn(Opcodes.GOTO, L_done);
855
856 mv.visitLabel(L_rethrow);
857 mv.visitInsn(Opcodes.ATHROW);
858
859 mv.visitLabel(L_done);
860 }
861
862 private void emitPushArguments(Name args, int start) {
863 for (int i = start; i < args.arguments.length; i++) {
864 emitPushArgument(args, i);
865 }
866 }
867
868 private void emitPushArgument(Name name, int paramIndex) {
869 Object arg = name.arguments[paramIndex];
870 Class<?> ptype = name.function.methodType().parameterType(paramIndex);
871 emitPushArgument(ptype, arg);
872 }
873
874 private void emitPushArgument(Class<?> ptype, Object arg) {
875 BasicType bptype = basicType(ptype);
876 if (arg instanceof Name) {
877 Name n = (Name) arg;
878 emitLoadInsn(n.type, n.index());
879 emitImplicitConversion(n.type, ptype);
880 } else if ((arg == null || arg instanceof String) && bptype == L_TYPE) {
881 emitConst(arg);
882 } else {
883 if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
884 emitConst(arg);
885 } else {
886 mv.visitLdcInsn(constantPlaceholder(arg));
887 emitImplicitConversion(L_TYPE, ptype);
888 }
889 }
890 }
891
892 /**
893 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
894 */
895 private void emitReturn() {
896 // return statement
897 Class<?> rclass = invokerType.returnType();
898 BasicType rtype = lambdaForm.returnType();
899 assert(rtype == basicType(rclass)); // must agree
900 if (rtype == V_TYPE) {
901 // void
902 mv.visitInsn(Opcodes.RETURN);
903 // it doesn't matter what rclass is; the JVM will discard any value
904 } else {
905 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
906
907 // put return value on the stack if it is not already there
908 if (lambdaForm.result != lambdaForm.names.length - 1 ||
909 lambdaForm.result < lambdaForm.arity) {
910 emitLoadInsn(rn.type, lambdaForm.result);
911 }
912
913 emitImplicitConversion(rtype, rclass);
914
915 // generate actual return statement
916 emitReturnInsn(rtype);
917 }
918 }
919
920 /**
921 * Emit a type conversion bytecode casting from "from" to "to".
922 */
923 private void emitPrimCast(Wrapper from, Wrapper to) {
924 // Here's how.
925 // - indicates forbidden
926 // <-> indicates implicit
927 // to ----> boolean byte short char int long float double
928 // from boolean <-> - - - - - - -
929 // byte - <-> i2s i2c <-> i2l i2f i2d
930 // short - i2b <-> i2c <-> i2l i2f i2d
931 // char - i2b i2s <-> <-> i2l i2f i2d
932 // int - i2b i2s i2c <-> i2l i2f i2d
933 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
934 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
935 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
936 if (from == to) {
937 // no cast required, should be dead code anyway
938 return;
939 }
940 if (from.isSubwordOrInt()) {
941 // cast from {byte,short,char,int} to anything
942 emitI2X(to);
943 } else {
944 // cast from {long,float,double} to anything
945 if (to.isSubwordOrInt()) {
946 // cast to {byte,short,char,int}
947 emitX2I(from);
948 if (to.bitWidth() < 32) {
949 // targets other than int require another conversion
950 emitI2X(to);
951 }
952 } else {
953 // cast to {long,float,double} - this is verbose
954 boolean error = false;
955 switch (from) {
956 case LONG:
957 switch (to) {
958 case FLOAT: mv.visitInsn(Opcodes.L2F); break;
959 case DOUBLE: mv.visitInsn(Opcodes.L2D); break;
960 default: error = true; break;
961 }
962 break;
963 case FLOAT:
964 switch (to) {
965 case LONG : mv.visitInsn(Opcodes.F2L); break;
966 case DOUBLE: mv.visitInsn(Opcodes.F2D); break;
967 default: error = true; break;
968 }
969 break;
970 case DOUBLE:
971 switch (to) {
972 case LONG : mv.visitInsn(Opcodes.D2L); break;
973 case FLOAT: mv.visitInsn(Opcodes.D2F); break;
974 default: error = true; break;
975 }
976 break;
977 default:
978 error = true;
979 break;
980 }
981 if (error) {
982 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
983 }
984 }
985 }
986 }
987
988 private void emitI2X(Wrapper type) {
989 switch (type) {
990 case BYTE: mv.visitInsn(Opcodes.I2B); break;
991 case SHORT: mv.visitInsn(Opcodes.I2S); break;
992 case CHAR: mv.visitInsn(Opcodes.I2C); break;
993 case INT: /* naught */ break;
994 case LONG: mv.visitInsn(Opcodes.I2L); break;
995 case FLOAT: mv.visitInsn(Opcodes.I2F); break;
996 case DOUBLE: mv.visitInsn(Opcodes.I2D); break;
997 case BOOLEAN:
998 // For compatibility with ValueConversions and explicitCastArguments:
999 mv.visitInsn(Opcodes.ICONST_1);
1000 mv.visitInsn(Opcodes.IAND);
1001 break;
1002 default: throw new InternalError("unknown type: " + type);
1003 }
1004 }
1005
1006 private void emitX2I(Wrapper type) {
1007 switch (type) {
1008 case LONG: mv.visitInsn(Opcodes.L2I); break;
1009 case FLOAT: mv.visitInsn(Opcodes.F2I); break;
1010 case DOUBLE: mv.visitInsn(Opcodes.D2I); break;
1011 default: throw new InternalError("unknown type: " + type);
1012 }
1013 }
1014
1015 /**
1016 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1017 */
1018 static MemberName generateLambdaFormInterpreterEntryPoint(String sig) {
1019 assert(isValidSignature(sig));
1020 String name = "interpret_"+signatureReturn(sig).basicTypeChar();
1021 MethodType type = signatureType(sig); // sig includes leading argument
1022 type = type.changeParameterType(0, MethodHandle.class);
1023 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", name, type);
1024 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1025 }
1026
1027 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1028 classFilePrologue();
1029
1030 // Suppress this method in backtraces displayed to the user.
1031 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Hidden;", true);
1032
1033 // Don't inline the interpreter entry.
1034 mv.visitAnnotation("Ljava/lang/invoke/DontInline;", true);
1035
1036 // create parameter array
1037 emitIconstInsn(invokerType.parameterCount());
1038 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
1039
1040 // fill parameter array
1041 for (int i = 0; i < invokerType.parameterCount(); i++) {
1042 Class<?> ptype = invokerType.parameterType(i);
1043 mv.visitInsn(Opcodes.DUP);
1044 emitIconstInsn(i);
1045 emitLoadInsn(basicType(ptype), i);
1046 // box if primitive type
1047 if (ptype.isPrimitive()) {
1048 emitBoxing(Wrapper.forPrimitiveType(ptype));
1049 }
1050 mv.visitInsn(Opcodes.AASTORE);
1051 }
1052 // invoke
1053 emitAloadInsn(0);
1054 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;");
1055 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable
1056 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false);
1057
1058 // maybe unbox
1059 Class<?> rtype = invokerType.returnType();
1060 if (rtype.isPrimitive() && rtype != void.class) {
1061 emitUnboxing(Wrapper.forPrimitiveType(rtype));
1062 }
1063
1064 // return statement
1065 emitReturnInsn(basicType(rtype));
1066
1067 classFileEpilogue();
1068 bogusMethod(invokerType);
1069
1070 final byte[] classFile = cw.toByteArray();
1071 maybeDump(className, classFile);
1072 return classFile;
1073 }
1074
1075 /**
1076 * Generate bytecode for a NamedFunction invoker.
1077 */
1078 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1079 MethodType invokerType = NamedFunction.INVOKER_METHOD_TYPE;
1080 String invokerName = "invoke_" + shortenSignature(basicTypeSignature(typeForm.erasedType()));
1081 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1082 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1083 }
1084
1085 static int nfi = 0;
1086
1087 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1088 MethodType dstType = typeForm.erasedType();
1089 classFilePrologue();
1090
1091 // Suppress this method in backtraces displayed to the user.
1092 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Hidden;", true);
1093
1094 // Force inlining of this invoker method.
1095 mv.visitAnnotation("Ljava/lang/invoke/ForceInline;", true);
1096
1097 // Load receiver
1098 emitAloadInsn(0);
1099
1100 // Load arguments from array
1101 for (int i = 0; i < dstType.parameterCount(); i++) {
1102 emitAloadInsn(1);
1103 emitIconstInsn(i);
1104 mv.visitInsn(Opcodes.AALOAD);
1105
1106 // Maybe unbox
1107 Class<?> dptype = dstType.parameterType(i);
1108 if (dptype.isPrimitive()) {
1109 Class<?> sptype = dstType.basicType().wrap().parameterType(i);
1110 Wrapper dstWrapper = Wrapper.forBasicType(dptype);
1111 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int
1112 emitUnboxing(srcWrapper);
1113 emitPrimCast(srcWrapper, dstWrapper);
1114 }
1115 }
1116
1117 // Invoke
1118 String targetDesc = dstType.basicType().toMethodDescriptorString();
1119 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false);
1120
1121 // Box primitive types
1122 Class<?> rtype = dstType.returnType();
1123 if (rtype != void.class && rtype.isPrimitive()) {
1124 Wrapper srcWrapper = Wrapper.forBasicType(rtype);
1125 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int
1126 // boolean casts not allowed
1127 emitPrimCast(srcWrapper, dstWrapper);
1128 emitBoxing(dstWrapper);
1129 }
1130
1131 // If the return type is void we return a null reference.
1132 if (rtype == void.class) {
1133 mv.visitInsn(Opcodes.ACONST_NULL);
1134 }
1135 emitReturnInsn(L_TYPE); // NOTE: NamedFunction invokers always return a reference value.
1136
1137 classFileEpilogue();
1138 bogusMethod(dstType);
1139
1140 final byte[] classFile = cw.toByteArray();
1141 maybeDump(className, classFile);
1142 return classFile;
1143 }
1144
1145 /**
1146 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1147 * for debugging purposes.
1148 */
1149 private void bogusMethod(Object... os) {
1150 if (DUMP_CLASS_FILES) {
1151 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null);
1152 for (Object o : os) {
1153 mv.visitLdcInsn(o.toString());
1154 mv.visitInsn(Opcodes.POP);
1155 }
1156 mv.visitInsn(Opcodes.RETURN);
1157 mv.visitMaxs(0, 0);
1158 mv.visitEnd();
1159 }
1160 }
1161 }