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 java.lang.invoke.LambdaForm.Name;
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 sun.invoke.util.VerifyType;
42
43 /**
44 * Code generation backend for LambdaForm.
45 * <p>
46 * @author John Rose, JSR 292 EG
47 */
48 class InvokerBytecodeGenerator {
49 /** Define class names for convenience. */
50 private static final String MH = "java/lang/invoke/MethodHandle";
51 private static final String MHI = "java/lang/invoke/MethodHandleImpl";
52 private static final String LF = "java/lang/invoke/LambdaForm";
53 private static final String LFN = "java/lang/invoke/LambdaForm$Name";
54 private static final String CLS = "java/lang/Class";
55 private static final String OBJ = "java/lang/Object";
56 private static final String OBJARY = "[Ljava/lang/Object;";
57
58 private static final String LF_SIG = "L" + LF + ";";
59 private static final String LFN_SIG = "L" + LFN + ";";
60 private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";";
61 private static final String CLL_SIG = "(L" + CLS + ";L" + OBJ + ";)L" + OBJ + ";";
62
63 /** Name of its super class*/
64 private static final String superName = LF;
65
66 /** Name of new class */
67 private final String className;
68
69 /** Name of the source file (for stack trace printing). */
70 private final String sourceFile;
71
72 private final LambdaForm lambdaForm;
73 private final String invokerName;
74 private final MethodType invokerType;
75 private final int[] localsMap;
76
77 /** ASM bytecode generation. */
78 private ClassWriter cw;
79 private MethodVisitor mv;
80
81 private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
82 private static final Class<?> HOST_CLASS = LambdaForm.class;
83
84 private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
85 String className, String invokerName, MethodType invokerType) {
86 if (invokerName.contains(".")) {
87 int p = invokerName.indexOf(".");
88 className = invokerName.substring(0, p);
89 invokerName = invokerName.substring(p+1);
90 }
91 if (DUMP_CLASS_FILES) {
92 className = makeDumpableClassName(className);
93 }
94 this.className = superName + "$" + className;
95 this.sourceFile = "LambdaForm$" + className;
96 this.lambdaForm = lambdaForm;
97 this.invokerName = invokerName;
98 this.invokerType = invokerType;
99 this.localsMap = new int[localsMapSize];
100 }
101
102 private InvokerBytecodeGenerator(String className, String invokerName, MethodType invokerType) {
103 this(null, invokerType.parameterCount(),
104 className, invokerName, invokerType);
105 // Create an array to map name indexes to locals indexes.
106 for (int i = 0; i < localsMap.length; i++) {
107 localsMap[i] = invokerType.parameterSlotCount() - invokerType.parameterSlotDepth(i);
108 }
109 }
110
111 private InvokerBytecodeGenerator(String className, LambdaForm form, MethodType invokerType) {
112 this(form, form.names.length,
113 className, form.debugName, invokerType);
114 // Create an array to map name indexes to locals indexes.
115 Name[] names = form.names;
116 for (int i = 0, index = 0; i < localsMap.length; i++) {
117 localsMap[i] = index;
118 index += Wrapper.forBasicType(names[i].type).stackSlots();
119 }
120 }
121
122
123 /** instance counters for dumped classes */
124 private final static HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS;
125 /** debugging flag for saving generated class files */
126 private final static File DUMP_CLASS_FILES_DIR;
127
128 static {
129 if (DUMP_CLASS_FILES) {
130 DUMP_CLASS_FILES_COUNTERS = new HashMap<>();
131 try {
132 File dumpDir = new File("DUMP_CLASS_FILES");
133 if (!dumpDir.exists()) {
134 dumpDir.mkdirs();
135 }
136 DUMP_CLASS_FILES_DIR = dumpDir;
137 System.out.println("Dumping class files to "+DUMP_CLASS_FILES_DIR+"/...");
138 } catch (Exception e) {
139 throw newInternalError(e);
140 }
141 } else {
142 DUMP_CLASS_FILES_COUNTERS = null;
143 DUMP_CLASS_FILES_DIR = null;
144 }
145 }
146
147 static void maybeDump(final String className, final byte[] classFile) {
148 if (DUMP_CLASS_FILES) {
149 System.out.println("dump: " + className);
150 java.security.AccessController.doPrivileged(
151 new java.security.PrivilegedAction<Void>() {
152 public Void run() {
153 try {
154 String dumpName = className;
155 //dumpName = dumpName.replace('/', '-');
156 File dumpFile = new File(DUMP_CLASS_FILES_DIR, dumpName+".class");
157 dumpFile.getParentFile().mkdirs();
158 FileOutputStream file = new FileOutputStream(dumpFile);
159 file.write(classFile);
160 file.close();
161 return null;
162 } catch (IOException ex) {
163 throw newInternalError(ex);
164 }
165 }
166 });
167 }
168
169 }
170
171 private static String makeDumpableClassName(String className) {
172 Integer ctr;
173 synchronized (DUMP_CLASS_FILES_COUNTERS) {
174 ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
175 if (ctr == null) ctr = 0;
176 DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
177 }
178 String sfx = ctr.toString();
179 while (sfx.length() < 3)
180 sfx = "0"+sfx;
181 className += sfx;
182 return className;
183 }
184
185 class CpPatch {
186 final int index;
187 final String placeholder;
188 final Object value;
189 CpPatch(int index, String placeholder, Object value) {
190 this.index = index;
191 this.placeholder = placeholder;
192 this.value = value;
193 }
194 public String toString() {
195 return "CpPatch/index="+index+",placeholder="+placeholder+",value="+value;
196 }
197 }
198
199 Map<Object, CpPatch> cpPatches = new HashMap<>();
200
201 int cph = 0; // for counting constant placeholders
202
203 String constantPlaceholder(Object arg) {
204 String cpPlaceholder = "CONSTANT_PLACEHOLDER_" + cph++;
205 if (DUMP_CLASS_FILES) cpPlaceholder += " <<" + arg.toString() + ">>"; // debugging aid
206 if (cpPatches.containsKey(cpPlaceholder)) {
207 throw new InternalError("observed CP placeholder twice: " + cpPlaceholder);
208 }
209 // insert placeholder in CP and remember the patch
210 int index = cw.newConst((Object) cpPlaceholder); // TODO check if aready in the constant pool
211 cpPatches.put(cpPlaceholder, new CpPatch(index, cpPlaceholder, arg));
212 return cpPlaceholder;
213 }
214
215 Object[] cpPatches(byte[] classFile) {
216 int size = getConstantPoolSize(classFile);
217 Object[] res = new Object[size];
218 for (CpPatch p : cpPatches.values()) {
219 if (p.index >= size)
220 throw new InternalError("in cpool["+size+"]: "+p+"\n"+Arrays.toString(Arrays.copyOf(classFile, 20)));
221 res[p.index] = p.value;
222 }
223 return res;
224 }
225
226 /**
227 * Extract the number of constant pool entries from a given class file.
228 *
229 * @param classFile the bytes of the class file in question.
230 * @return the number of entries in the constant pool.
231 */
232 private static int getConstantPoolSize(byte[] classFile) {
233 // The first few bytes:
234 // u4 magic;
235 // u2 minor_version;
236 // u2 major_version;
237 // u2 constant_pool_count;
238 return ((classFile[8] & 0xFF) << 8) | (classFile[9] & 0xFF);
239 }
240
241 /**
242 * Extract the MemberName of a newly-defined method.
243 */
244 private MemberName loadMethod(byte[] classFile) {
245 Class<?> invokerClass = loadAndInitializeInvokerClass(classFile, cpPatches(classFile));
246 return resolveInvokerMember(invokerClass, invokerName, invokerType);
247 }
248
249 /**
250 * Define a given class as anonymous class in the runtime system.
251 */
252 private static Class<?> loadAndInitializeInvokerClass(byte[] classBytes, Object[] patches) {
253 Class<?> invokerClass = UNSAFE.defineAnonymousClass(HOST_CLASS, classBytes, patches);
254 UNSAFE.ensureClassInitialized(invokerClass); // Make sure the class is initialized; VM might complain.
255 return invokerClass;
256 }
257
258 private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
259 MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
260 //System.out.println("resolveInvokerMember => "+member);
261 //for (Method m : invokerClass.getDeclaredMethods()) System.out.println(" "+m);
262 try {
263 member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member, HOST_CLASS, ReflectiveOperationException.class);
264 } catch (ReflectiveOperationException e) {
265 throw newInternalError(e);
266 }
267 //System.out.println("resolveInvokerMember => "+member);
268 return member;
269 }
270
271 /**
272 * Set up class file generation.
273 */
274 private void classFilePrologue() {
275 cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
276 cw.visit(Opcodes.V1_8, Opcodes.ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER, className, null, superName, null);
277 cw.visitSource(sourceFile, null);
278
279 String invokerDesc = invokerType.toMethodDescriptorString();
280 mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null);
281 }
282
283 /**
284 * Tear down class file generation.
285 */
286 private void classFileEpilogue() {
287 mv.visitMaxs(0, 0);
288 mv.visitEnd();
289 }
290
291 /*
292 * Low-level emit helpers.
293 */
294 private void emitConst(Object con) {
295 if (con == null) {
296 mv.visitInsn(Opcodes.ACONST_NULL);
297 return;
298 }
299 if (con instanceof Integer) {
300 emitIconstInsn((int) con);
301 return;
302 }
303 if (con instanceof Long) {
304 long x = (long) con;
305 if (x == (short) x) {
306 emitIconstInsn((int) x);
307 mv.visitInsn(Opcodes.I2L);
308 return;
309 }
310 }
311 if (con instanceof Float) {
312 float x = (float) con;
313 if (x == (short) x) {
314 emitIconstInsn((int) x);
315 mv.visitInsn(Opcodes.I2F);
316 return;
317 }
318 }
319 if (con instanceof Double) {
320 double x = (double) con;
321 if (x == (short) x) {
322 emitIconstInsn((int) x);
323 mv.visitInsn(Opcodes.I2D);
324 return;
325 }
326 }
327 if (con instanceof Boolean) {
328 emitIconstInsn((boolean) con ? 1 : 0);
329 return;
330 }
331 // fall through:
332 mv.visitLdcInsn(con);
333 }
334
335 private void emitIconstInsn(int i) {
336 int opcode;
337 switch (i) {
338 case 0: opcode = Opcodes.ICONST_0; break;
339 case 1: opcode = Opcodes.ICONST_1; break;
340 case 2: opcode = Opcodes.ICONST_2; break;
341 case 3: opcode = Opcodes.ICONST_3; break;
342 case 4: opcode = Opcodes.ICONST_4; break;
343 case 5: opcode = Opcodes.ICONST_5; break;
344 default:
345 if (i == (byte) i) {
346 mv.visitIntInsn(Opcodes.BIPUSH, i & 0xFF);
347 } else if (i == (short) i) {
348 mv.visitIntInsn(Opcodes.SIPUSH, (char) i);
349 } else {
350 mv.visitLdcInsn(i);
351 }
352 return;
353 }
354 mv.visitInsn(opcode);
355 }
356
357 /*
358 * NOTE: These load/store methods use the localsMap to find the correct index!
359 */
360 private void emitLoadInsn(char type, int index) {
361 int opcode;
362 switch (type) {
363 case 'I': opcode = Opcodes.ILOAD; break;
364 case 'J': opcode = Opcodes.LLOAD; break;
365 case 'F': opcode = Opcodes.FLOAD; break;
366 case 'D': opcode = Opcodes.DLOAD; break;
367 case 'L': opcode = Opcodes.ALOAD; break;
368 default:
369 throw new InternalError("unknown type: " + type);
370 }
371 mv.visitVarInsn(opcode, localsMap[index]);
372 }
373 private void emitAloadInsn(int index) {
374 emitLoadInsn('L', index);
375 }
376
377 private void emitStoreInsn(char type, int index) {
378 int opcode;
379 switch (type) {
380 case 'I': opcode = Opcodes.ISTORE; break;
381 case 'J': opcode = Opcodes.LSTORE; break;
382 case 'F': opcode = Opcodes.FSTORE; break;
383 case 'D': opcode = Opcodes.DSTORE; break;
384 case 'L': opcode = Opcodes.ASTORE; break;
385 default:
386 throw new InternalError("unknown type: " + type);
387 }
388 mv.visitVarInsn(opcode, localsMap[index]);
389 }
390 private void emitAstoreInsn(int index) {
391 emitStoreInsn('L', index);
392 }
393
394 /**
395 * Emit a boxing call.
396 *
397 * @param type primitive type class to box.
398 */
399 private void emitBoxing(Class<?> type) {
400 Wrapper wrapper = Wrapper.forPrimitiveType(type);
401 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
402 String name = "valueOf";
403 String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";";
404 mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false);
405 }
406
407 /**
408 * Emit an unboxing call (plus preceding checkcast).
409 *
410 * @param type wrapper type class to unbox.
411 */
412 private void emitUnboxing(Class<?> type) {
413 Wrapper wrapper = Wrapper.forWrapperType(type);
414 String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
415 String name = wrapper.primitiveSimpleName() + "Value";
416 String desc = "()" + wrapper.basicTypeChar();
417 mv.visitTypeInsn(Opcodes.CHECKCAST, owner);
418 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false);
419 }
420
421 /**
422 * Emit an implicit conversion.
423 *
424 * @param ptype type of value present on stack
425 * @param pclass type of value required on stack
426 */
427 private void emitImplicitConversion(char ptype, Class<?> pclass) {
428 switch (ptype) {
429 case 'L':
430 if (VerifyType.isNullConversion(Object.class, pclass))
431 return;
432 if (isStaticallyNameable(pclass)) {
433 mv.visitTypeInsn(Opcodes.CHECKCAST, getInternalName(pclass));
434 } else {
435 mv.visitLdcInsn(constantPlaceholder(pclass));
436 mv.visitTypeInsn(Opcodes.CHECKCAST, CLS);
437 mv.visitInsn(Opcodes.SWAP);
438 mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "castReference", CLL_SIG, false);
439 if (pclass.isArray())
440 mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY);
441 }
442 return;
443 case 'I':
444 if (!VerifyType.isNullConversion(int.class, pclass))
445 emitPrimCast(ptype, Wrapper.basicTypeChar(pclass));
446 return;
447 case 'J':
448 assert(pclass == long.class);
449 return;
450 case 'F':
451 assert(pclass == float.class);
452 return;
453 case 'D':
454 assert(pclass == double.class);
455 return;
456 }
457 throw new InternalError("bad implicit conversion: tc="+ptype+": "+pclass);
458 }
459
460 /**
461 * Emits an actual return instruction conforming to the given return type.
462 */
463 private void emitReturnInsn(Class<?> type) {
464 int opcode;
465 switch (Wrapper.basicTypeChar(type)) {
466 case 'I': opcode = Opcodes.IRETURN; break;
467 case 'J': opcode = Opcodes.LRETURN; break;
468 case 'F': opcode = Opcodes.FRETURN; break;
469 case 'D': opcode = Opcodes.DRETURN; break;
470 case 'L': opcode = Opcodes.ARETURN; break;
471 case 'V': opcode = Opcodes.RETURN; break;
472 default:
473 throw new InternalError("unknown return type: " + type);
474 }
475 mv.visitInsn(opcode);
476 }
477
478 private static String getInternalName(Class<?> c) {
479 assert(VerifyAccess.isTypeVisible(c, Object.class));
480 return c.getName().replace('.', '/');
481 }
482
483 /**
484 * Generate customized bytecode for a given LambdaForm.
485 */
486 static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
487 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
488 return g.loadMethod(g.generateCustomizedCodeBytes());
489 }
490
491 /**
492 * Generate an invoker method for the passed {@link LambdaForm}.
493 */
494 private byte[] generateCustomizedCodeBytes() {
495 classFilePrologue();
496
497 // Suppress this method in backtraces displayed to the user.
498 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Hidden;", true);
499
500 // Mark this method as a compiled LambdaForm
501 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Compiled;", true);
502
503 // Force inlining of this invoker method.
504 mv.visitAnnotation("Ljava/lang/invoke/ForceInline;", true);
505
506 // iterate over the form's names, generating bytecode instructions for each
507 // start iterating at the first name following the arguments
508 for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
509 Name name = lambdaForm.names[i];
510 MemberName member = name.function.member();
511
512 if (isSelectAlternative(i)) {
513 emitSelectAlternative(name, lambdaForm.names[i + 1]);
514 i++; // skip MH.invokeBasic of the selectAlternative result
515 } else if (isGuardWithCatch(i)) {
516 emitGuardWithCatch(i);
517 i = i+2; // Jump to the end of GWC idiom
518 } else if (isStaticallyInvocable(member)) {
519 emitStaticInvoke(member, name);
520 } else {
521 emitInvoke(name);
522 }
523
524 // Update cached form name's info in case an intrinsic spanning multiple names was encountered.
525 name = lambdaForm.names[i];
526 member = name.function.member();
527
528 // store the result from evaluating to the target name in a local if required
529 // (if this is the last value, i.e., the one that is going to be returned,
530 // avoid store/load/return and just return)
531 if (i == lambdaForm.names.length - 1 && i == lambdaForm.result) {
532 // return value - do nothing
533 } else if (name.type != 'V') {
534 // non-void: actually assign
535 emitStoreInsn(name.type, name.index());
536 }
537 }
538
539 // return statement
540 emitReturn();
541
542 classFileEpilogue();
543 bogusMethod(lambdaForm);
544
545 final byte[] classFile = cw.toByteArray();
546 maybeDump(className, classFile);
547 return classFile;
548 }
549
550 /**
551 * Emit an invoke for the given name.
552 */
553 void emitInvoke(Name name) {
554 if (true) {
555 // push receiver
556 MethodHandle target = name.function.resolvedHandle;
557 assert(target != null) : name.exprString();
558 mv.visitLdcInsn(constantPlaceholder(target));
559 mv.visitTypeInsn(Opcodes.CHECKCAST, MH);
560 } else {
561 // load receiver
562 emitAloadInsn(0);
563 mv.visitTypeInsn(Opcodes.CHECKCAST, MH);
564 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG);
565 mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG);
566 // TODO more to come
567 }
568
569 // push arguments
570 for (int i = 0; i < name.arguments.length; i++) {
571 emitPushArgument(name, i);
572 }
573
574 // invocation
575 MethodType type = name.function.methodType();
576 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
577 }
578
579 static private Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
580 // Sample classes from each package we are willing to bind to statically:
581 java.lang.Object.class,
582 java.util.Arrays.class,
583 sun.misc.Unsafe.class
584 //MethodHandle.class already covered
585 };
586
587 static boolean isStaticallyInvocable(MemberName member) {
588 if (member == null) return false;
589 if (member.isConstructor()) return false;
590 Class<?> cls = member.getDeclaringClass();
591 if (cls.isArray() || cls.isPrimitive())
592 return false; // FIXME
593 if (cls.isAnonymousClass() || cls.isLocalClass())
594 return false; // inner class of some sort
595 if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
596 return false; // not on BCP
597 MethodType mtype = member.getMethodOrFieldType();
598 if (!isStaticallyNameable(mtype.returnType()))
599 return false;
600 for (Class<?> ptype : mtype.parameterArray())
601 if (!isStaticallyNameable(ptype))
602 return false;
603 if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
604 return true; // in java.lang.invoke package
605 if (member.isPublic() && isStaticallyNameable(cls))
606 return true;
607 return false;
608 }
609
610 static boolean isStaticallyNameable(Class<?> cls) {
611 while (cls.isArray())
612 cls = cls.getComponentType();
613 if (cls.isPrimitive())
614 return true; // int[].class, for example
615 // could use VerifyAccess.isClassAccessible but the following is a safe approximation
616 if (cls.getClassLoader() != Object.class.getClassLoader())
617 return false;
618 if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
619 return true;
620 if (!Modifier.isPublic(cls.getModifiers()))
621 return false;
622 for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
623 if (VerifyAccess.isSamePackage(pkgcls, cls))
624 return true;
625 }
626 return false;
627 }
628
629 /**
630 * Emit an invoke for the given name, using the MemberName directly.
631 */
632 void emitStaticInvoke(MemberName member, Name name) {
633 assert(member.equals(name.function.member()));
634 String cname = getInternalName(member.getDeclaringClass());
635 String mname = member.getName();
636 String mtype;
637 byte refKind = member.getReferenceKind();
638 if (refKind == REF_invokeSpecial) {
639 // in order to pass the verifier, we need to convert this to invokevirtual in all cases
640 assert(member.canBeStaticallyBound()) : member;
641 refKind = REF_invokeVirtual;
642 }
643
644 if (member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual) {
645 // Methods from Object declared in an interface can be resolved by JVM to invokevirtual kind.
646 // Need to convert it back to invokeinterface to pass verification and make the invocation works as expected.
647 refKind = REF_invokeInterface;
648 }
649
650 // push arguments
651 for (int i = 0; i < name.arguments.length; i++) {
652 emitPushArgument(name, i);
653 }
654
655 // invocation
656 if (member.isMethod()) {
657 mtype = member.getMethodType().toMethodDescriptorString();
658 mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype,
659 member.getDeclaringClass().isInterface());
660 } else {
661 mtype = MethodType.toFieldDescriptorString(member.getFieldType());
662 mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype);
663 }
664 }
665 int refKindOpcode(byte refKind) {
666 switch (refKind) {
667 case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL;
668 case REF_invokeStatic: return Opcodes.INVOKESTATIC;
669 case REF_invokeSpecial: return Opcodes.INVOKESPECIAL;
670 case REF_invokeInterface: return Opcodes.INVOKEINTERFACE;
671 case REF_getField: return Opcodes.GETFIELD;
672 case REF_putField: return Opcodes.PUTFIELD;
673 case REF_getStatic: return Opcodes.GETSTATIC;
674 case REF_putStatic: return Opcodes.PUTSTATIC;
675 }
676 throw new InternalError("refKind="+refKind);
677 }
678
679 /**
680 * Check if MemberName is a call to a method named {@code name} in class {@code declaredClass}.
681 */
682 private boolean memberRefersTo(MemberName member, Class<?> declaringClass, String name) {
683 return member != null &&
684 member.getDeclaringClass() == declaringClass &&
685 member.getName().equals(name);
686 }
687 private boolean nameRefersTo(Name name, Class<?> declaringClass, String methodName) {
688 return name.function != null &&
689 memberRefersTo(name.function.member(), declaringClass, methodName);
690 }
691
692 /**
693 * Check if MemberName is a call to MethodHandle.invokeBasic.
694 */
695 private boolean isInvokeBasic(Name name) {
696 if (name.function == null)
697 return false;
698 if (name.arguments.length < 1)
699 return false; // must have MH argument
700 MemberName member = name.function.member();
701 return memberRefersTo(member, MethodHandle.class, "invokeBasic") &&
702 !member.isPublic() && !member.isStatic();
703 }
704
705 /**
706 * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
707 */
708 private boolean isSelectAlternative(int pos) {
709 // selectAlternative idiom:
710 // t_{n}:L=MethodHandleImpl.selectAlternative(...)
711 // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
712 if (pos+1 >= lambdaForm.names.length) return false;
713 Name name0 = lambdaForm.names[pos];
714 Name name1 = lambdaForm.names[pos+1];
715 return nameRefersTo(name0, MethodHandleImpl.class, "selectAlternative") &&
716 isInvokeBasic(name1) &&
717 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
718 lambdaForm.lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
719 }
720
721 /**
722 * Check if i-th name is a start of GuardWithCatch idiom.
723 */
724 private boolean isGuardWithCatch(int pos) {
725 // GuardWithCatch idiom:
726 // t_{n}:L=MethodHandle.invokeBasic(...)
727 // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
728 // t_{n+2}:?=MethodHandle.invokeBasic(t_{n+1})
729 if (pos+2 >= lambdaForm.names.length) return false;
730 Name name0 = lambdaForm.names[pos];
731 Name name1 = lambdaForm.names[pos+1];
732 Name name2 = lambdaForm.names[pos+2];
733 return nameRefersTo(name1, MethodHandleImpl.class, "guardWithCatch") &&
734 isInvokeBasic(name0) &&
735 isInvokeBasic(name2) &&
736 name1.lastUseIndex(name0) == 3 && // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
737 lambdaForm.lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
738 name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(t_{n+1})
739 lambdaForm.lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
740 }
741
742 /**
743 * Emit bytecode for the selectAlternative idiom.
744 *
745 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
746 * <blockquote><pre>{@code
747 * Lambda(a0:L,a1:I)=>{
748 * t2:I=foo.test(a1:I);
749 * t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
750 * t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
751 * }</pre></blockquote>
752 */
753 private void emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) {
754 Name receiver = (Name) invokeBasicName.arguments[0];
755
756 Label L_fallback = new Label();
757 Label L_done = new Label();
758
759 // load test result
760 emitPushArgument(selectAlternativeName, 0);
761 mv.visitInsn(Opcodes.ICONST_1);
762
763 // if_icmpne L_fallback
764 mv.visitJumpInsn(Opcodes.IF_ICMPNE, L_fallback);
765
766 // invoke selectAlternativeName.arguments[1]
767 emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative
768 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
769 emitInvoke(invokeBasicName);
770
771 // goto L_done
772 mv.visitJumpInsn(Opcodes.GOTO, L_done);
773
774 // L_fallback:
775 mv.visitLabel(L_fallback);
776
777 // invoke selectAlternativeName.arguments[2]
778 emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative
779 emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
780 emitInvoke(invokeBasicName);
781
782 // L_done:
783 mv.visitLabel(L_done);
784 }
785
786 /**
787 * Emit bytecode for the guardWithCatch idiom.
788 *
789 * The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
790 * <blockquote><pre>{@code
791 * guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
792 * t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
793 * t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
794 * t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
795 * }</pre></blockquote>
796 *
797 * It is compiled into bytecode equivalent of the following code:
798 * <blockquote><pre>{@code
799 * try {
800 * return a1.invokeBasic(a6, a7);
801 * } catch (Throwable e) {
802 * if (!a2.isInstance(e)) throw e;
803 * return a3.invokeBasic(ex, a6, a7);
804 * }}
805 */
806 private void emitGuardWithCatch(int pos) {
807 Name args = lambdaForm.names[pos];
808 Name invoker = lambdaForm.names[pos+1];
809 Name result = lambdaForm.names[pos+2];
810
811 Label L_startBlock = new Label();
812 Label L_endBlock = new Label();
813 Label L_handler = new Label();
814 Label L_done = new Label();
815
816 Class<?> returnType = result.function.resolvedHandle.type().returnType();
817 MethodType type = args.function.resolvedHandle.type()
818 .dropParameterTypes(0,1)
819 .changeReturnType(returnType);
820
821 mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable");
822
823 // Normal case
824 mv.visitLabel(L_startBlock);
825 // load target
826 emitPushArgument(invoker, 0);
827 emitPushArguments(args, 1); // skip 1st argument: method handle
828 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
829 mv.visitLabel(L_endBlock);
830 mv.visitJumpInsn(Opcodes.GOTO, L_done);
831
832 // Exceptional case
833 mv.visitLabel(L_handler);
834
835 // Check exception's type
836 mv.visitInsn(Opcodes.DUP);
837 // load exception class
838 emitPushArgument(invoker, 1);
839 mv.visitInsn(Opcodes.SWAP);
840 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false);
841 Label L_rethrow = new Label();
842 mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow);
843
844 // Invoke catcher
845 // load catcher
846 emitPushArgument(invoker, 2);
847 mv.visitInsn(Opcodes.SWAP);
848 emitPushArguments(args, 1); // skip 1st argument: method handle
849 MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
850 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false);
851 mv.visitJumpInsn(Opcodes.GOTO, L_done);
852
853 mv.visitLabel(L_rethrow);
854 mv.visitInsn(Opcodes.ATHROW);
855
856 mv.visitLabel(L_done);
857 }
858
859 private void emitPushArguments(Name args, int start) {
860 for (int i = start; i < args.arguments.length; i++) {
861 emitPushArgument(args, i);
862 }
863 }
864
865 private void emitPushArgument(Name name, int paramIndex) {
866 Object arg = name.arguments[paramIndex];
867 char ptype = name.function.parameterType(paramIndex);
868 MethodType mtype = name.function.methodType();
869 if (arg instanceof Name) {
870 Name n = (Name) arg;
871 emitLoadInsn(n.type, n.index());
872 emitImplicitConversion(n.type, mtype.parameterType(paramIndex));
873 } else if ((arg == null || arg instanceof String) && ptype == 'L') {
874 emitConst(arg);
875 } else {
876 if (Wrapper.isWrapperType(arg.getClass()) && ptype != 'L') {
877 emitConst(arg);
878 } else {
879 mv.visitLdcInsn(constantPlaceholder(arg));
880 emitImplicitConversion('L', mtype.parameterType(paramIndex));
881 }
882 }
883 }
884
885 /**
886 * Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
887 */
888 private void emitReturn() {
889 // return statement
890 if (lambdaForm.result == -1) {
891 // void
892 mv.visitInsn(Opcodes.RETURN);
893 } else {
894 LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
895 char rtype = Wrapper.basicTypeChar(invokerType.returnType());
896
897 // put return value on the stack if it is not already there
898 if (lambdaForm.result != lambdaForm.names.length - 1) {
899 emitLoadInsn(rn.type, lambdaForm.result);
900 }
901
902 // potentially generate cast
903 // rtype is the return type of the invoker - generated code must conform to this
904 // rn.type is the type of the result Name in the LF
905 if (rtype != rn.type) {
906 // need cast
907 if (rtype == 'L') {
908 // possibly cast the primitive to the correct type for boxing
909 char boxedType = Wrapper.forWrapperType(invokerType.returnType()).basicTypeChar();
910 if (boxedType != rn.type) {
911 emitPrimCast(rn.type, boxedType);
912 }
913 // cast primitive to reference ("boxing")
914 emitBoxing(invokerType.returnType());
915 } else {
916 // to-primitive cast
917 if (rn.type != 'L') {
918 // prim-to-prim cast
919 emitPrimCast(rn.type, rtype);
920 } else {
921 // ref-to-prim cast ("unboxing")
922 throw new InternalError("no ref-to-prim (unboxing) casts supported right now");
923 }
924 }
925 }
926
927 // generate actual return statement
928 emitReturnInsn(invokerType.returnType());
929 }
930 }
931
932 /**
933 * Emit a type conversion bytecode casting from "from" to "to".
934 */
935 private void emitPrimCast(char from, char to) {
936 // Here's how.
937 // - indicates forbidden
938 // <-> indicates implicit
939 // to ----> boolean byte short char int long float double
940 // from boolean <-> - - - - - - -
941 // byte - <-> i2s i2c <-> i2l i2f i2d
942 // short - i2b <-> i2c <-> i2l i2f i2d
943 // char - i2b i2s <-> <-> i2l i2f i2d
944 // int - i2b i2s i2c <-> i2l i2f i2d
945 // long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
946 // float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
947 // double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
948 if (from == to) {
949 // no cast required, should be dead code anyway
950 return;
951 }
952 Wrapper wfrom = Wrapper.forBasicType(from);
953 Wrapper wto = Wrapper.forBasicType(to);
954 if (wfrom.isSubwordOrInt()) {
955 // cast from {byte,short,char,int} to anything
956 emitI2X(to);
957 } else {
958 // cast from {long,float,double} to anything
959 if (wto.isSubwordOrInt()) {
960 // cast to {byte,short,char,int}
961 emitX2I(from);
962 if (wto.bitWidth() < 32) {
963 // targets other than int require another conversion
964 emitI2X(to);
965 }
966 } else {
967 // cast to {long,float,double} - this is verbose
968 boolean error = false;
969 switch (from) {
970 case 'J':
971 if (to == 'F') { mv.visitInsn(Opcodes.L2F); }
972 else if (to == 'D') { mv.visitInsn(Opcodes.L2D); }
973 else error = true;
974 break;
975 case 'F':
976 if (to == 'J') { mv.visitInsn(Opcodes.F2L); }
977 else if (to == 'D') { mv.visitInsn(Opcodes.F2D); }
978 else error = true;
979 break;
980 case 'D':
981 if (to == 'J') { mv.visitInsn(Opcodes.D2L); }
982 else if (to == 'F') { mv.visitInsn(Opcodes.D2F); }
983 else error = true;
984 break;
985 default:
986 error = true;
987 break;
988 }
989 if (error) {
990 throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
991 }
992 }
993 }
994 }
995
996 private void emitI2X(char type) {
997 switch (type) {
998 case 'B': mv.visitInsn(Opcodes.I2B); break;
999 case 'S': mv.visitInsn(Opcodes.I2S); break;
1000 case 'C': mv.visitInsn(Opcodes.I2C); break;
1001 case 'I': /* naught */ break;
1002 case 'J': mv.visitInsn(Opcodes.I2L); break;
1003 case 'F': mv.visitInsn(Opcodes.I2F); break;
1004 case 'D': mv.visitInsn(Opcodes.I2D); break;
1005 case 'Z':
1006 // For compatibility with ValueConversions and explicitCastArguments:
1007 mv.visitInsn(Opcodes.ICONST_1);
1008 mv.visitInsn(Opcodes.IAND);
1009 break;
1010 default: throw new InternalError("unknown type: " + type);
1011 }
1012 }
1013
1014 private void emitX2I(char type) {
1015 switch (type) {
1016 case 'J': mv.visitInsn(Opcodes.L2I); break;
1017 case 'F': mv.visitInsn(Opcodes.F2I); break;
1018 case 'D': mv.visitInsn(Opcodes.D2I); break;
1019 default: throw new InternalError("unknown type: " + type);
1020 }
1021 }
1022
1023 private static String basicTypeCharSignature(String prefix, MethodType type) {
1024 StringBuilder buf = new StringBuilder(prefix);
1025 for (Class<?> ptype : type.parameterList())
1026 buf.append(Wrapper.forBasicType(ptype).basicTypeChar());
1027 buf.append('_').append(Wrapper.forBasicType(type.returnType()).basicTypeChar());
1028 return buf.toString();
1029 }
1030
1031 /**
1032 * Generate bytecode for a LambdaForm.vmentry which calls interpretWithArguments.
1033 */
1034 static MemberName generateLambdaFormInterpreterEntryPoint(String sig) {
1035 assert(LambdaForm.isValidSignature(sig));
1036 //System.out.println("generateExactInvoker "+sig);
1037 // compute method type
1038 // first parameter and return type
1039 char tret = LambdaForm.signatureReturn(sig);
1040 MethodType type = MethodType.methodType(LambdaForm.typeClass(tret), MethodHandle.class);
1041 // other parameter types
1042 int arity = LambdaForm.signatureArity(sig);
1043 for (int i = 1; i < arity; i++) {
1044 type = type.appendParameterTypes(LambdaForm.typeClass(sig.charAt(i)));
1045 }
1046 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("LFI", "interpret_"+tret, type);
1047 return g.loadMethod(g.generateLambdaFormInterpreterEntryPointBytes());
1048 }
1049
1050 private byte[] generateLambdaFormInterpreterEntryPointBytes() {
1051 classFilePrologue();
1052
1053 // Suppress this method in backtraces displayed to the user.
1054 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Hidden;", true);
1055
1056 // Don't inline the interpreter entry.
1057 mv.visitAnnotation("Ljava/lang/invoke/DontInline;", true);
1058
1059 // create parameter array
1060 emitIconstInsn(invokerType.parameterCount());
1061 mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
1062
1063 // fill parameter array
1064 for (int i = 0; i < invokerType.parameterCount(); i++) {
1065 Class<?> ptype = invokerType.parameterType(i);
1066 mv.visitInsn(Opcodes.DUP);
1067 emitIconstInsn(i);
1068 emitLoadInsn(Wrapper.basicTypeChar(ptype), i);
1069 // box if primitive type
1070 if (ptype.isPrimitive()) {
1071 emitBoxing(ptype);
1072 }
1073 mv.visitInsn(Opcodes.AASTORE);
1074 }
1075 // invoke
1076 emitAloadInsn(0);
1077 mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", "Ljava/lang/invoke/LambdaForm;");
1078 mv.visitInsn(Opcodes.SWAP); // swap form and array; avoid local variable
1079 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, LF, "interpretWithArguments", "([Ljava/lang/Object;)Ljava/lang/Object;", false);
1080
1081 // maybe unbox
1082 Class<?> rtype = invokerType.returnType();
1083 if (rtype.isPrimitive() && rtype != void.class) {
1084 emitUnboxing(Wrapper.asWrapperType(rtype));
1085 }
1086
1087 // return statement
1088 emitReturnInsn(rtype);
1089
1090 classFileEpilogue();
1091 bogusMethod(invokerType);
1092
1093 final byte[] classFile = cw.toByteArray();
1094 maybeDump(className, classFile);
1095 return classFile;
1096 }
1097
1098 /**
1099 * Generate bytecode for a NamedFunction invoker.
1100 */
1101 static MemberName generateNamedFunctionInvoker(MethodTypeForm typeForm) {
1102 MethodType invokerType = LambdaForm.NamedFunction.INVOKER_METHOD_TYPE;
1103 String invokerName = basicTypeCharSignature("invoke_", typeForm.erasedType());
1104 InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("NFI", invokerName, invokerType);
1105 return g.loadMethod(g.generateNamedFunctionInvokerImpl(typeForm));
1106 }
1107
1108 static int nfi = 0;
1109
1110 private byte[] generateNamedFunctionInvokerImpl(MethodTypeForm typeForm) {
1111 MethodType dstType = typeForm.erasedType();
1112 classFilePrologue();
1113
1114 // Suppress this method in backtraces displayed to the user.
1115 mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Hidden;", true);
1116
1117 // Force inlining of this invoker method.
1118 mv.visitAnnotation("Ljava/lang/invoke/ForceInline;", true);
1119
1120 // Load receiver
1121 emitAloadInsn(0);
1122
1123 // Load arguments from array
1124 for (int i = 0; i < dstType.parameterCount(); i++) {
1125 emitAloadInsn(1);
1126 emitIconstInsn(i);
1127 mv.visitInsn(Opcodes.AALOAD);
1128
1129 // Maybe unbox
1130 Class<?> dptype = dstType.parameterType(i);
1131 if (dptype.isPrimitive()) {
1132 Class<?> sptype = dstType.basicType().wrap().parameterType(i);
1133 Wrapper dstWrapper = Wrapper.forBasicType(dptype);
1134 Wrapper srcWrapper = dstWrapper.isSubwordOrInt() ? Wrapper.INT : dstWrapper; // narrow subword from int
1135 emitUnboxing(srcWrapper.wrapperType());
1136 emitPrimCast(srcWrapper.basicTypeChar(), dstWrapper.basicTypeChar());
1137 }
1138 }
1139
1140 // Invoke
1141 String targetDesc = dstType.basicType().toMethodDescriptorString();
1142 mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", targetDesc, false);
1143
1144 // Box primitive types
1145 Class<?> rtype = dstType.returnType();
1146 if (rtype != void.class && rtype.isPrimitive()) {
1147 Wrapper srcWrapper = Wrapper.forBasicType(rtype);
1148 Wrapper dstWrapper = srcWrapper.isSubwordOrInt() ? Wrapper.INT : srcWrapper; // widen subword to int
1149 // boolean casts not allowed
1150 emitPrimCast(srcWrapper.basicTypeChar(), dstWrapper.basicTypeChar());
1151 emitBoxing(dstWrapper.primitiveType());
1152 }
1153
1154 // If the return type is void we return a null reference.
1155 if (rtype == void.class) {
1156 mv.visitInsn(Opcodes.ACONST_NULL);
1157 }
1158 emitReturnInsn(Object.class); // NOTE: NamedFunction invokers always return a reference value.
1159
1160 classFileEpilogue();
1161 bogusMethod(dstType);
1162
1163 final byte[] classFile = cw.toByteArray();
1164 maybeDump(className, classFile);
1165 return classFile;
1166 }
1167
1168 /**
1169 * Emit a bogus method that just loads some string constants. This is to get the constants into the constant pool
1170 * for debugging purposes.
1171 */
1172 private void bogusMethod(Object... os) {
1173 if (DUMP_CLASS_FILES) {
1174 mv = cw.visitMethod(Opcodes.ACC_STATIC, "dummy", "()V", null, null);
1175 for (Object o : os) {
1176 mv.visitLdcInsn(o.toString());
1177 mv.visitInsn(Opcodes.POP);
1178 }
1179 mv.visitInsn(Opcodes.RETURN);
1180 mv.visitMaxs(0, 0);
1181 mv.visitEnd();
1182 }
1183 }
1184 }