JDK8/Java8源码在线阅读
/*
* Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.lang.invoke;
import java.io.*;
import java.util.*;
import java.lang.reflect.Modifier;
import jdk.internal.org.objectweb.asm.*;
import static java.lang.invoke.LambdaForm.*;
import static java.lang.invoke.LambdaForm.BasicType.*;
import static java.lang.invoke.MethodHandleStatics.*;
import static java.lang.invoke.MethodHandleNatives.Constants.*;
import sun.invoke.util.VerifyAccess;
import sun.invoke.util.VerifyType;
import sun.invoke.util.Wrapper;
import sun.reflect.misc.ReflectUtil;
/**
* Code generation backend for LambdaForm.
* <p>
* @author John Rose, JSR 292 EG
*/
class InvokerBytecodeGenerator {
/** Define class names for convenience. */
private static final String MH = "java/lang/invoke/MethodHandle";
private static final String MHI = "java/lang/invoke/MethodHandleImpl";
private static final String LF = "java/lang/invoke/LambdaForm";
private static final String LFN = "java/lang/invoke/LambdaForm$Name";
private static final String CLS = "java/lang/Class";
private static final String OBJ = "java/lang/Object";
private static final String OBJARY = "[Ljava/lang/Object;";
private static final String LF_SIG = "L" + LF + ";";
private static final String LFN_SIG = "L" + LFN + ";";
private static final String LL_SIG = "(L" + OBJ + ";)L" + OBJ + ";";
private static final String CLL_SIG = "(L" + CLS + ";L" + OBJ + ";)L" + OBJ + ";";
/** Name of its super class*/
private static final String superName = OBJ;
/** Name of new class */
private final String className;
/** Name of the source file (for stack trace printing). */
private final String sourceFile;
private final LambdaForm lambdaForm;
private final String invokerName;
private final MethodType invokerType;
/** Info about local variables in compiled lambda form */
private final int[] localsMap; // index
private final BasicType[] localTypes; // basic type
private final Class<?>[] localClasses; // type
/** ASM bytecode generation. */
private ClassWriter cw;
private MethodVisitor mv;
private static final MemberName.Factory MEMBERNAME_FACTORY = MemberName.getFactory();
private static final Class<?> HOST_CLASS = LambdaForm.class;
/** Main constructor; other constructors delegate to this one. */
private InvokerBytecodeGenerator(LambdaForm lambdaForm, int localsMapSize,
String className, String invokerName, MethodType invokerType) {
if (invokerName.contains(".")) {
int p = invokerName.indexOf(".");
className = invokerName.substring(0, p);
invokerName = invokerName.substring(p+1);
}
if (DUMP_CLASS_FILES) {
className = makeDumpableClassName(className);
}
this.className = LF + "$" + className;
this.sourceFile = "LambdaForm$" + className;
this.lambdaForm = lambdaForm;
this.invokerName = invokerName;
this.invokerType = invokerType;
this.localsMap = new int[localsMapSize+1];
// last entry of localsMap is count of allocated local slots
this.localTypes = new BasicType[localsMapSize+1];
this.localClasses = new Class<?>[localsMapSize+1];
}
/** For generating LambdaForm interpreter entry points. */
private InvokerBytecodeGenerator(String className, String invokerName, MethodType invokerType) {
this(null, invokerType.parameterCount(),
className, invokerName, invokerType);
// Create an array to map name indexes to locals indexes.
localTypes[localTypes.length - 1] = V_TYPE;
for (int i = 0; i < localsMap.length; i++) {
localsMap[i] = invokerType.parameterSlotCount() - invokerType.parameterSlotDepth(i);
if (i < invokerType.parameterCount())
localTypes[i] = basicType(invokerType.parameterType(i));
}
}
/** For generating customized code for a single LambdaForm. */
private InvokerBytecodeGenerator(String className, LambdaForm form, MethodType invokerType) {
this(form, form.names.length,
className, form.debugName, invokerType);
// Create an array to map name indexes to locals indexes.
Name[] names = form.names;
for (int i = 0, index = 0; i < localsMap.length; i++) {
localsMap[i] = index;
if (i < names.length) {
BasicType type = names[i].type();
index += type.basicTypeSlots();
localTypes[i] = type;
}
}
}
/** instance counters for dumped classes */
private final static HashMap<String,Integer> DUMP_CLASS_FILES_COUNTERS;
/** debugging flag for saving generated class files */
private final static File DUMP_CLASS_FILES_DIR;
static {
if (DUMP_CLASS_FILES) {
DUMP_CLASS_FILES_COUNTERS = new HashMap<>();
try {
File dumpDir = new File("DUMP_CLASS_FILES");
if (!dumpDir.exists()) {
dumpDir.mkdirs();
}
DUMP_CLASS_FILES_DIR = dumpDir;
System.out.println("Dumping class files to "+DUMP_CLASS_FILES_DIR+"/...");
} catch (Exception e) {
throw newInternalError(e);
}
} else {
DUMP_CLASS_FILES_COUNTERS = null;
DUMP_CLASS_FILES_DIR = null;
}
}
static void maybeDump(final String className, final byte[] classFile) {
if (DUMP_CLASS_FILES) {
java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction<Void>() {
public Void run() {
try {
String dumpName = className;
//dumpName = dumpName.replace('/', '-');
File dumpFile = new File(DUMP_CLASS_FILES_DIR, dumpName+".class");
System.out.println("dump: " + dumpFile);
dumpFile.getParentFile().mkdirs();
FileOutputStream file = new FileOutputStream(dumpFile);
file.write(classFile);
file.close();
return null;
} catch (IOException ex) {
throw newInternalError(ex);
}
}
});
}
}
private static String makeDumpableClassName(String className) {
Integer ctr;
synchronized (DUMP_CLASS_FILES_COUNTERS) {
ctr = DUMP_CLASS_FILES_COUNTERS.get(className);
if (ctr == null) ctr = 0;
DUMP_CLASS_FILES_COUNTERS.put(className, ctr+1);
}
String sfx = ctr.toString();
while (sfx.length() < 3)
sfx = "0"+sfx;
className += sfx;
return className;
}
class CpPatch {
final int index;
final String placeholder;
final Object value;
CpPatch(int index, String placeholder, Object value) {
this.index = index;
this.placeholder = placeholder;
this.value = value;
}
public String toString() {
return "CpPatch/index="+index+",placeholder="+placeholder+",value="+value;
}
}
Map<Object, CpPatch> cpPatches = new HashMap<>();
int cph = 0; // for counting constant placeholders
String constantPlaceholder(Object arg) {
String cpPlaceholder = "CONSTANT_PLACEHOLDER_" + cph++;
if (DUMP_CLASS_FILES) cpPlaceholder += " <<" + debugString(arg) + ">>"; // debugging aid
if (cpPatches.containsKey(cpPlaceholder)) {
throw new InternalError("observed CP placeholder twice: " + cpPlaceholder);
}
// insert placeholder in CP and remember the patch
int index = cw.newConst((Object) cpPlaceholder); // TODO check if aready in the constant pool
cpPatches.put(cpPlaceholder, new CpPatch(index, cpPlaceholder, arg));
return cpPlaceholder;
}
Object[] cpPatches(byte[] classFile) {
int size = getConstantPoolSize(classFile);
Object[] res = new Object[size];
for (CpPatch p : cpPatches.values()) {
if (p.index >= size)
throw new InternalError("in cpool["+size+"]: "+p+"\n"+Arrays.toString(Arrays.copyOf(classFile, 20)));
res[p.index] = p.value;
}
return res;
}
private static String debugString(Object arg) {
if (arg instanceof MethodHandle) {
MethodHandle mh = (MethodHandle) arg;
MemberName member = mh.internalMemberName();
if (member != null)
return member.toString();
return mh.debugString();
}
return arg.toString();
}
/**
* Extract the number of constant pool entries from a given class file.
*
* @param classFile the bytes of the class file in question.
* @return the number of entries in the constant pool.
*/
private static int getConstantPoolSize(byte[] classFile) {
// The first few bytes:
// u4 magic;
// u2 minor_version;
// u2 major_version;
// u2 constant_pool_count;
return ((classFile[8] & 0xFF) << 8) | (classFile[9] & 0xFF);
}
/**
* Extract the MemberName of a newly-defined method.
*/
private MemberName loadMethod(byte[] classFile) {
Class<?> invokerClass = loadAndInitializeInvokerClass(classFile, cpPatches(classFile));
return resolveInvokerMember(invokerClass, invokerName, invokerType);
}
/**
* Define a given class as anonymous class in the runtime system.
*/
private static Class<?> loadAndInitializeInvokerClass(byte[] classBytes, Object[] patches) {
Class<?> invokerClass = UNSAFE.defineAnonymousClass(HOST_CLASS, classBytes, patches);
UNSAFE.ensureClassInitialized(invokerClass); // Make sure the class is initialized; VM might complain.
return invokerClass;
}
private static MemberName resolveInvokerMember(Class<?> invokerClass, String name, MethodType type) {
MemberName member = new MemberName(invokerClass, name, type, REF_invokeStatic);
//System.out.println("resolveInvokerMember => "+member);
//for (Method m : invokerClass.getDeclaredMethods()) System.out.println(" "+m);
try {
member = MEMBERNAME_FACTORY.resolveOrFail(REF_invokeStatic, member, HOST_CLASS, ReflectiveOperationException.class);
} catch (ReflectiveOperationException e) {
throw newInternalError(e);
}
//System.out.println("resolveInvokerMember => "+member);
return member;
}
/**
* Set up class file generation.
*/
private void classFilePrologue() {
final int NOT_ACC_PUBLIC = 0; // not ACC_PUBLIC
cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
cw.visit(Opcodes.V1_8, NOT_ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER, className, null, superName, null);
cw.visitSource(sourceFile, null);
String invokerDesc = invokerType.toMethodDescriptorString();
mv = cw.visitMethod(Opcodes.ACC_STATIC, invokerName, invokerDesc, null, null);
}
/**
* Tear down class file generation.
*/
private void classFileEpilogue() {
mv.visitMaxs(0, 0);
mv.visitEnd();
}
/*
* Low-level emit helpers.
*/
private void emitConst(Object con) {
if (con == null) {
mv.visitInsn(Opcodes.ACONST_NULL);
return;
}
if (con instanceof Integer) {
emitIconstInsn((int) con);
return;
}
if (con instanceof Long) {
long x = (long) con;
if (x == (short) x) {
emitIconstInsn((int) x);
mv.visitInsn(Opcodes.I2L);
return;
}
}
if (con instanceof Float) {
float x = (float) con;
if (x == (short) x) {
emitIconstInsn((int) x);
mv.visitInsn(Opcodes.I2F);
return;
}
}
if (con instanceof Double) {
double x = (double) con;
if (x == (short) x) {
emitIconstInsn((int) x);
mv.visitInsn(Opcodes.I2D);
return;
}
}
if (con instanceof Boolean) {
emitIconstInsn((boolean) con ? 1 : 0);
return;
}
// fall through:
mv.visitLdcInsn(con);
}
private void emitIconstInsn(int i) {
int opcode;
switch (i) {
case 0: opcode = Opcodes.ICONST_0; break;
case 1: opcode = Opcodes.ICONST_1; break;
case 2: opcode = Opcodes.ICONST_2; break;
case 3: opcode = Opcodes.ICONST_3; break;
case 4: opcode = Opcodes.ICONST_4; break;
case 5: opcode = Opcodes.ICONST_5; break;
default:
if (i == (byte) i) {
mv.visitIntInsn(Opcodes.BIPUSH, i & 0xFF);
} else if (i == (short) i) {
mv.visitIntInsn(Opcodes.SIPUSH, (char) i);
} else {
mv.visitLdcInsn(i);
}
return;
}
mv.visitInsn(opcode);
}
/*
* NOTE: These load/store methods use the localsMap to find the correct index!
*/
private void emitLoadInsn(BasicType type, int index) {
int opcode = loadInsnOpcode(type);
mv.visitVarInsn(opcode, localsMap[index]);
}
private int loadInsnOpcode(BasicType type) throws InternalError {
switch (type) {
case I_TYPE: return Opcodes.ILOAD;
case J_TYPE: return Opcodes.LLOAD;
case F_TYPE: return Opcodes.FLOAD;
case D_TYPE: return Opcodes.DLOAD;
case L_TYPE: return Opcodes.ALOAD;
default:
throw new InternalError("unknown type: " + type);
}
}
private void emitAloadInsn(int index) {
emitLoadInsn(L_TYPE, index);
}
private void emitStoreInsn(BasicType type, int index) {
int opcode = storeInsnOpcode(type);
mv.visitVarInsn(opcode, localsMap[index]);
}
private int storeInsnOpcode(BasicType type) throws InternalError {
switch (type) {
case I_TYPE: return Opcodes.ISTORE;
case J_TYPE: return Opcodes.LSTORE;
case F_TYPE: return Opcodes.FSTORE;
case D_TYPE: return Opcodes.DSTORE;
case L_TYPE: return Opcodes.ASTORE;
default:
throw new InternalError("unknown type: " + type);
}
}
private void emitAstoreInsn(int index) {
emitStoreInsn(L_TYPE, index);
}
private byte arrayTypeCode(Wrapper elementType) {
switch (elementType) {
case BOOLEAN: return Opcodes.T_BOOLEAN;
case BYTE: return Opcodes.T_BYTE;
case CHAR: return Opcodes.T_CHAR;
case SHORT: return Opcodes.T_SHORT;
case INT: return Opcodes.T_INT;
case LONG: return Opcodes.T_LONG;
case FLOAT: return Opcodes.T_FLOAT;
case DOUBLE: return Opcodes.T_DOUBLE;
case OBJECT: return 0; // in place of Opcodes.T_OBJECT
default: throw new InternalError();
}
}
private int arrayInsnOpcode(byte tcode, int aaop) throws InternalError {
assert(aaop == Opcodes.AASTORE || aaop == Opcodes.AALOAD);
int xas;
switch (tcode) {
case Opcodes.T_BOOLEAN: xas = Opcodes.BASTORE; break;
case Opcodes.T_BYTE: xas = Opcodes.BASTORE; break;
case Opcodes.T_CHAR: xas = Opcodes.CASTORE; break;
case Opcodes.T_SHORT: xas = Opcodes.SASTORE; break;
case Opcodes.T_INT: xas = Opcodes.IASTORE; break;
case Opcodes.T_LONG: xas = Opcodes.LASTORE; break;
case Opcodes.T_FLOAT: xas = Opcodes.FASTORE; break;
case Opcodes.T_DOUBLE: xas = Opcodes.DASTORE; break;
case 0: xas = Opcodes.AASTORE; break;
default: throw new InternalError();
}
return xas - Opcodes.AASTORE + aaop;
}
private void freeFrameLocal(int oldFrameLocal) {
int i = indexForFrameLocal(oldFrameLocal);
if (i < 0) return;
BasicType type = localTypes[i];
int newFrameLocal = makeLocalTemp(type);
mv.visitVarInsn(loadInsnOpcode(type), oldFrameLocal);
mv.visitVarInsn(storeInsnOpcode(type), newFrameLocal);
assert(localsMap[i] == oldFrameLocal);
localsMap[i] = newFrameLocal;
assert(indexForFrameLocal(oldFrameLocal) < 0);
}
private int indexForFrameLocal(int frameLocal) {
for (int i = 0; i < localsMap.length; i++) {
if (localsMap[i] == frameLocal && localTypes[i] != V_TYPE)
return i;
}
return -1;
}
private int makeLocalTemp(BasicType type) {
int frameLocal = localsMap[localsMap.length - 1];
localsMap[localsMap.length - 1] = frameLocal + type.basicTypeSlots();
return frameLocal;
}
/**
* Emit a boxing call.
*
* @param wrapper primitive type class to box.
*/
private void emitBoxing(Wrapper wrapper) {
String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
String name = "valueOf";
String desc = "(" + wrapper.basicTypeChar() + ")L" + owner + ";";
mv.visitMethodInsn(Opcodes.INVOKESTATIC, owner, name, desc, false);
}
/**
* Emit an unboxing call (plus preceding checkcast).
*
* @param wrapper wrapper type class to unbox.
*/
private void emitUnboxing(Wrapper wrapper) {
String owner = "java/lang/" + wrapper.wrapperType().getSimpleName();
String name = wrapper.primitiveSimpleName() + "Value";
String desc = "()" + wrapper.basicTypeChar();
emitReferenceCast(wrapper.wrapperType(), null);
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, owner, name, desc, false);
}
/**
* Emit an implicit conversion for an argument which must be of the given pclass.
* This is usually a no-op, except when pclass is a subword type or a reference other than Object or an interface.
*
* @param ptype type of value present on stack
* @param pclass type of value required on stack
* @param arg compile-time representation of value on stack (Node, constant) or null if none
*/
private void emitImplicitConversion(BasicType ptype, Class<?> pclass, Object arg) {
assert(basicType(pclass) == ptype); // boxing/unboxing handled by caller
if (pclass == ptype.basicTypeClass() && ptype != L_TYPE)
return; // nothing to do
switch (ptype) {
case L_TYPE:
if (VerifyType.isNullConversion(Object.class, pclass, false)) {
if (PROFILE_LEVEL > 0)
emitReferenceCast(Object.class, arg);
return;
}
emitReferenceCast(pclass, arg);
return;
case I_TYPE:
if (!VerifyType.isNullConversion(int.class, pclass, false))
emitPrimCast(ptype.basicTypeWrapper(), Wrapper.forPrimitiveType(pclass));
return;
}
throw newInternalError("bad implicit conversion: tc="+ptype+": "+pclass);
}
/** Update localClasses type map. Return true if the information is already present. */
private boolean assertStaticType(Class<?> cls, Name n) {
int local = n.index();
Class<?> aclass = localClasses[local];
if (aclass != null && (aclass == cls || cls.isAssignableFrom(aclass))) {
return true; // type info is already present
} else if (aclass == null || aclass.isAssignableFrom(cls)) {
localClasses[local] = cls; // type info can be improved
}
return false;
}
private void emitReferenceCast(Class<?> cls, Object arg) {
Name writeBack = null; // local to write back result
if (arg instanceof Name) {
Name n = (Name) arg;
if (assertStaticType(cls, n))
return; // this cast was already performed
if (lambdaForm.useCount(n) > 1) {
// This guy gets used more than once.
writeBack = n;
}
}
if (isStaticallyNameable(cls)) {
String sig = getInternalName(cls);
mv.visitTypeInsn(Opcodes.CHECKCAST, sig);
} else {
mv.visitLdcInsn(constantPlaceholder(cls));
mv.visitTypeInsn(Opcodes.CHECKCAST, CLS);
mv.visitInsn(Opcodes.SWAP);
mv.visitMethodInsn(Opcodes.INVOKESTATIC, MHI, "castReference", CLL_SIG, false);
if (Object[].class.isAssignableFrom(cls))
mv.visitTypeInsn(Opcodes.CHECKCAST, OBJARY);
else if (PROFILE_LEVEL > 0)
mv.visitTypeInsn(Opcodes.CHECKCAST, OBJ);
}
if (writeBack != null) {
mv.visitInsn(Opcodes.DUP);
emitAstoreInsn(writeBack.index());
}
}
/**
* Emits an actual return instruction conforming to the given return type.
*/
private void emitReturnInsn(BasicType type) {
int opcode;
switch (type) {
case I_TYPE: opcode = Opcodes.IRETURN; break;
case J_TYPE: opcode = Opcodes.LRETURN; break;
case F_TYPE: opcode = Opcodes.FRETURN; break;
case D_TYPE: opcode = Opcodes.DRETURN; break;
case L_TYPE: opcode = Opcodes.ARETURN; break;
case V_TYPE: opcode = Opcodes.RETURN; break;
default:
throw new InternalError("unknown return type: " + type);
}
mv.visitInsn(opcode);
}
private static String getInternalName(Class<?> c) {
if (c == Object.class) return OBJ;
else if (c == Object[].class) return OBJARY;
else if (c == Class.class) return CLS;
else if (c == MethodHandle.class) return MH;
assert(VerifyAccess.isTypeVisible(c, Object.class)) : c.getName();
return c.getName().replace('.', '/');
}
/**
* Generate customized bytecode for a given LambdaForm.
*/
static MemberName generateCustomizedCode(LambdaForm form, MethodType invokerType) {
InvokerBytecodeGenerator g = new InvokerBytecodeGenerator("MH", form, invokerType);
return g.loadMethod(g.generateCustomizedCodeBytes());
}
/**
* Generate an invoker method for the passed {@link LambdaForm}.
*/
private byte[] generateCustomizedCodeBytes() {
classFilePrologue();
// Suppress this method in backtraces displayed to the user.
mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Hidden;", true);
// Mark this method as a compiled LambdaForm
mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Compiled;", true);
if (lambdaForm.forceInline) {
// Force inlining of this invoker method.
mv.visitAnnotation("Ljava/lang/invoke/ForceInline;", true);
} else {
mv.visitAnnotation("Ljava/lang/invoke/DontInline;", true);
}
// iterate over the form's names, generating bytecode instructions for each
// start iterating at the first name following the arguments
Name onStack = null;
for (int i = lambdaForm.arity; i < lambdaForm.names.length; i++) {
Name name = lambdaForm.names[i];
emitStoreResult(onStack);
onStack = name; // unless otherwise modified below
MethodHandleImpl.Intrinsic intr = name.function.intrinsicName();
switch (intr) {
case SELECT_ALTERNATIVE:
assert isSelectAlternative(i);
onStack = emitSelectAlternative(name, lambdaForm.names[i+1]);
i++; // skip MH.invokeBasic of the selectAlternative result
continue;
case GUARD_WITH_CATCH:
assert isGuardWithCatch(i);
onStack = emitGuardWithCatch(i);
i = i+2; // Jump to the end of GWC idiom
continue;
case NEW_ARRAY:
Class<?> rtype = name.function.methodType().returnType();
if (isStaticallyNameable(rtype)) {
emitNewArray(name);
continue;
}
break;
case ARRAY_LOAD:
emitArrayLoad(name);
continue;
case ARRAY_STORE:
emitArrayStore(name);
continue;
case IDENTITY:
assert(name.arguments.length == 1);
emitPushArguments(name);
continue;
case ZERO:
assert(name.arguments.length == 0);
emitConst(name.type.basicTypeWrapper().zero());
continue;
case NONE:
// no intrinsic associated
break;
default:
throw newInternalError("Unknown intrinsic: "+intr);
}
MemberName member = name.function.member();
if (isStaticallyInvocable(member)) {
emitStaticInvoke(member, name);
} else {
emitInvoke(name);
}
}
// return statement
emitReturn(onStack);
classFileEpilogue();
bogusMethod(lambdaForm);
final byte[] classFile = cw.toByteArray();
maybeDump(className, classFile);
return classFile;
}
void emitArrayLoad(Name name) { emitArrayOp(name, Opcodes.AALOAD); }
void emitArrayStore(Name name) { emitArrayOp(name, Opcodes.AASTORE); }
void emitArrayOp(Name name, int arrayOpcode) {
assert arrayOpcode == Opcodes.AALOAD || arrayOpcode == Opcodes.AASTORE;
Class<?> elementType = name.function.methodType().parameterType(0).getComponentType();
assert elementType != null;
emitPushArguments(name);
if (elementType.isPrimitive()) {
Wrapper w = Wrapper.forPrimitiveType(elementType);
arrayOpcode = arrayInsnOpcode(arrayTypeCode(w), arrayOpcode);
}
mv.visitInsn(arrayOpcode);
}
/**
* Emit an invoke for the given name.
*/
void emitInvoke(Name name) {
assert(!isLinkerMethodInvoke(name)); // should use the static path for these
if (true) {
// push receiver
MethodHandle target = name.function.resolvedHandle;
assert(target != null) : name.exprString();
mv.visitLdcInsn(constantPlaceholder(target));
emitReferenceCast(MethodHandle.class, target);
} else {
// load receiver
emitAloadInsn(0);
emitReferenceCast(MethodHandle.class, null);
mv.visitFieldInsn(Opcodes.GETFIELD, MH, "form", LF_SIG);
mv.visitFieldInsn(Opcodes.GETFIELD, LF, "names", LFN_SIG);
// TODO more to come
}
// push arguments
emitPushArguments(name);
// invocation
MethodType type = name.function.methodType();
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
}
static private Class<?>[] STATICALLY_INVOCABLE_PACKAGES = {
// Sample classes from each package we are willing to bind to statically:
java.lang.Object.class,
java.util.Arrays.class,
sun.misc.Unsafe.class
//MethodHandle.class already covered
};
static boolean isStaticallyInvocable(Name name) {
return isStaticallyInvocable(name.function.member());
}
static boolean isStaticallyInvocable(MemberName member) {
if (member == null) return false;
if (member.isConstructor()) return false;
Class<?> cls = member.getDeclaringClass();
if (cls.isArray() || cls.isPrimitive())
return false; // FIXME
if (cls.isAnonymousClass() || cls.isLocalClass())
return false; // inner class of some sort
if (cls.getClassLoader() != MethodHandle.class.getClassLoader())
return false; // not on BCP
if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added
return false;
MethodType mtype = member.getMethodOrFieldType();
if (!isStaticallyNameable(mtype.returnType()))
return false;
for (Class<?> ptype : mtype.parameterArray())
if (!isStaticallyNameable(ptype))
return false;
if (!member.isPrivate() && VerifyAccess.isSamePackage(MethodHandle.class, cls))
return true; // in java.lang.invoke package
if (member.isPublic() && isStaticallyNameable(cls))
return true;
return false;
}
static boolean isStaticallyNameable(Class<?> cls) {
if (cls == Object.class)
return true;
while (cls.isArray())
cls = cls.getComponentType();
if (cls.isPrimitive())
return true; // int[].class, for example
if (ReflectUtil.isVMAnonymousClass(cls)) // FIXME: switch to supported API once it is added
return false;
// could use VerifyAccess.isClassAccessible but the following is a safe approximation
if (cls.getClassLoader() != Object.class.getClassLoader())
return false;
if (VerifyAccess.isSamePackage(MethodHandle.class, cls))
return true;
if (!Modifier.isPublic(cls.getModifiers()))
return false;
for (Class<?> pkgcls : STATICALLY_INVOCABLE_PACKAGES) {
if (VerifyAccess.isSamePackage(pkgcls, cls))
return true;
}
return false;
}
void emitStaticInvoke(Name name) {
emitStaticInvoke(name.function.member(), name);
}
/**
* Emit an invoke for the given name, using the MemberName directly.
*/
void emitStaticInvoke(MemberName member, Name name) {
assert(member.equals(name.function.member()));
Class<?> defc = member.getDeclaringClass();
String cname = getInternalName(defc);
String mname = member.getName();
String mtype;
byte refKind = member.getReferenceKind();
if (refKind == REF_invokeSpecial) {
// in order to pass the verifier, we need to convert this to invokevirtual in all cases
assert(member.canBeStaticallyBound()) : member;
refKind = REF_invokeVirtual;
}
if (member.getDeclaringClass().isInterface() && refKind == REF_invokeVirtual) {
// Methods from Object declared in an interface can be resolved by JVM to invokevirtual kind.
// Need to convert it back to invokeinterface to pass verification and make the invocation works as expected.
refKind = REF_invokeInterface;
}
// push arguments
emitPushArguments(name);
// invocation
if (member.isMethod()) {
mtype = member.getMethodType().toMethodDescriptorString();
mv.visitMethodInsn(refKindOpcode(refKind), cname, mname, mtype,
member.getDeclaringClass().isInterface());
} else {
mtype = MethodType.toFieldDescriptorString(member.getFieldType());
mv.visitFieldInsn(refKindOpcode(refKind), cname, mname, mtype);
}
// Issue a type assertion for the result, so we can avoid casts later.
if (name.type == L_TYPE) {
Class<?> rtype = member.getInvocationType().returnType();
assert(!rtype.isPrimitive());
if (rtype != Object.class && !rtype.isInterface()) {
assertStaticType(rtype, name);
}
}
}
void emitNewArray(Name name) throws InternalError {
Class<?> rtype = name.function.methodType().returnType();
if (name.arguments.length == 0) {
// The array will be a constant.
Object emptyArray;
try {
emptyArray = name.function.resolvedHandle.invoke();
} catch (Throwable ex) {
throw newInternalError(ex);
}
assert(java.lang.reflect.Array.getLength(emptyArray) == 0);
assert(emptyArray.getClass() == rtype); // exact typing
mv.visitLdcInsn(constantPlaceholder(emptyArray));
emitReferenceCast(rtype, emptyArray);
return;
}
Class<?> arrayElementType = rtype.getComponentType();
assert(arrayElementType != null);
emitIconstInsn(name.arguments.length);
int xas = Opcodes.AASTORE;
if (!arrayElementType.isPrimitive()) {
mv.visitTypeInsn(Opcodes.ANEWARRAY, getInternalName(arrayElementType));
} else {
byte tc = arrayTypeCode(Wrapper.forPrimitiveType(arrayElementType));
xas = arrayInsnOpcode(tc, xas);
mv.visitIntInsn(Opcodes.NEWARRAY, tc);
}
// store arguments
for (int i = 0; i < name.arguments.length; i++) {
mv.visitInsn(Opcodes.DUP);
emitIconstInsn(i);
emitPushArgument(name, i);
mv.visitInsn(xas);
}
// the array is left on the stack
assertStaticType(rtype, name);
}
int refKindOpcode(byte refKind) {
switch (refKind) {
case REF_invokeVirtual: return Opcodes.INVOKEVIRTUAL;
case REF_invokeStatic: return Opcodes.INVOKESTATIC;
case REF_invokeSpecial: return Opcodes.INVOKESPECIAL;
case REF_invokeInterface: return Opcodes.INVOKEINTERFACE;
case REF_getField: return Opcodes.GETFIELD;
case REF_putField: return Opcodes.PUTFIELD;
case REF_getStatic: return Opcodes.GETSTATIC;
case REF_putStatic: return Opcodes.PUTSTATIC;
}
throw new InternalError("refKind="+refKind);
}
/**
* Check if MemberName is a call to a method named {@code name} in class {@code declaredClass}.
*/
private boolean memberRefersTo(MemberName member, Class<?> declaringClass, String name) {
return member != null &&
member.getDeclaringClass() == declaringClass &&
member.getName().equals(name);
}
private boolean nameRefersTo(Name name, Class<?> declaringClass, String methodName) {
return name.function != null &&
memberRefersTo(name.function.member(), declaringClass, methodName);
}
/**
* Check if MemberName is a call to MethodHandle.invokeBasic.
*/
private boolean isInvokeBasic(Name name) {
if (name.function == null)
return false;
if (name.arguments.length < 1)
return false; // must have MH argument
MemberName member = name.function.member();
return memberRefersTo(member, MethodHandle.class, "invokeBasic") &&
!member.isPublic() && !member.isStatic();
}
/**
* Check if MemberName is a call to MethodHandle.linkToStatic, etc.
*/
private boolean isLinkerMethodInvoke(Name name) {
if (name.function == null)
return false;
if (name.arguments.length < 1)
return false; // must have MH argument
MemberName member = name.function.member();
return member != null &&
member.getDeclaringClass() == MethodHandle.class &&
!member.isPublic() && member.isStatic() &&
member.getName().startsWith("linkTo");
}
/**
* Check if i-th name is a call to MethodHandleImpl.selectAlternative.
*/
private boolean isSelectAlternative(int pos) {
// selectAlternative idiom:
// t_{n}:L=MethodHandleImpl.selectAlternative(...)
// t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
if (pos+1 >= lambdaForm.names.length) return false;
Name name0 = lambdaForm.names[pos];
Name name1 = lambdaForm.names[pos+1];
return nameRefersTo(name0, MethodHandleImpl.class, "selectAlternative") &&
isInvokeBasic(name1) &&
name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
lambdaForm.lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
}
/**
* Check if i-th name is a start of GuardWithCatch idiom.
*/
private boolean isGuardWithCatch(int pos) {
// GuardWithCatch idiom:
// t_{n}:L=MethodHandle.invokeBasic(...)
// t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
// t_{n+2}:?=MethodHandle.invokeBasic(t_{n+1})
if (pos+2 >= lambdaForm.names.length) return false;
Name name0 = lambdaForm.names[pos];
Name name1 = lambdaForm.names[pos+1];
Name name2 = lambdaForm.names[pos+2];
return nameRefersTo(name1, MethodHandleImpl.class, "guardWithCatch") &&
isInvokeBasic(name0) &&
isInvokeBasic(name2) &&
name1.lastUseIndex(name0) == 3 && // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
lambdaForm.lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(t_{n+1})
lambdaForm.lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
}
/**
* Emit bytecode for the selectAlternative idiom.
*
* The pattern looks like (Cf. MethodHandleImpl.makeGuardWithTest):
* <blockquote><pre>{@code
* Lambda(a0:L,a1:I)=>{
* t2:I=foo.test(a1:I);
* t3:L=MethodHandleImpl.selectAlternative(t2:I,(MethodHandle(int)int),(MethodHandle(int)int));
* t4:I=MethodHandle.invokeBasic(t3:L,a1:I);t4:I}
* }</pre></blockquote>
*/
private Name emitSelectAlternative(Name selectAlternativeName, Name invokeBasicName) {
assert isStaticallyInvocable(invokeBasicName);
Name receiver = (Name) invokeBasicName.arguments[0];
Label L_fallback = new Label();
Label L_done = new Label();
// load test result
emitPushArgument(selectAlternativeName, 0);
// if_icmpne L_fallback
mv.visitJumpInsn(Opcodes.IFEQ, L_fallback);
// invoke selectAlternativeName.arguments[1]
Class<?>[] preForkClasses = localClasses.clone();
emitPushArgument(selectAlternativeName, 1); // get 2nd argument of selectAlternative
emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
emitStaticInvoke(invokeBasicName);
// goto L_done
mv.visitJumpInsn(Opcodes.GOTO, L_done);
// L_fallback:
mv.visitLabel(L_fallback);
// invoke selectAlternativeName.arguments[2]
System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
emitPushArgument(selectAlternativeName, 2); // get 3rd argument of selectAlternative
emitAstoreInsn(receiver.index()); // store the MH in the receiver slot
emitStaticInvoke(invokeBasicName);
// L_done:
mv.visitLabel(L_done);
// for now do not bother to merge typestate; just reset to the dominator state
System.arraycopy(preForkClasses, 0, localClasses, 0, preForkClasses.length);
return invokeBasicName; // return what's on stack
}
/**
* Emit bytecode for the guardWithCatch idiom.
*
* The pattern looks like (Cf. MethodHandleImpl.makeGuardWithCatch):
* <blockquote><pre>{@code
* guardWithCatch=Lambda(a0:L,a1:L,a2:L,a3:L,a4:L,a5:L,a6:L,a7:L)=>{
* t8:L=MethodHandle.invokeBasic(a4:L,a6:L,a7:L);
* t9:L=MethodHandleImpl.guardWithCatch(a1:L,a2:L,a3:L,t8:L);
* t10:I=MethodHandle.invokeBasic(a5:L,t9:L);t10:I}
* }</pre></blockquote>
*
* It is compiled into bytecode equivalent of the following code:
* <blockquote><pre>{@code
* try {
* return a1.invokeBasic(a6, a7);
* } catch (Throwable e) {
* if (!a2.isInstance(e)) throw e;
* return a3.invokeBasic(ex, a6, a7);
* }}
*/
private Name emitGuardWithCatch(int pos) {
Name args = lambdaForm.names[pos];
Name invoker = lambdaForm.names[pos+1];
Name result = lambdaForm.names[pos+2];
Label L_startBlock = new Label();
Label L_endBlock = new Label();
Label L_handler = new Label();
Label L_done = new Label();
Class<?> returnType = result.function.resolvedHandle.type().returnType();
MethodType type = args.function.resolvedHandle.type()
.dropParameterTypes(0,1)
.changeReturnType(returnType);
mv.visitTryCatchBlock(L_startBlock, L_endBlock, L_handler, "java/lang/Throwable");
// Normal case
mv.visitLabel(L_startBlock);
// load target
emitPushArgument(invoker, 0);
emitPushArguments(args, 1); // skip 1st argument: method handle
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", type.basicType().toMethodDescriptorString(), false);
mv.visitLabel(L_endBlock);
mv.visitJumpInsn(Opcodes.GOTO, L_done);
// Exceptional case
mv.visitLabel(L_handler);
// Check exception's type
mv.visitInsn(Opcodes.DUP);
// load exception class
emitPushArgument(invoker, 1);
mv.visitInsn(Opcodes.SWAP);
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Class", "isInstance", "(Ljava/lang/Object;)Z", false);
Label L_rethrow = new Label();
mv.visitJumpInsn(Opcodes.IFEQ, L_rethrow);
// Invoke catcher
// load catcher
emitPushArgument(invoker, 2);
mv.visitInsn(Opcodes.SWAP);
emitPushArguments(args, 1); // skip 1st argument: method handle
MethodType catcherType = type.insertParameterTypes(0, Throwable.class);
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, MH, "invokeBasic", catcherType.basicType().toMethodDescriptorString(), false);
mv.visitJumpInsn(Opcodes.GOTO, L_done);
mv.visitLabel(L_rethrow);
mv.visitInsn(Opcodes.ATHROW);
mv.visitLabel(L_done);
return result;
}
private void emitPushArguments(Name args) {
emitPushArguments(args, 0);
}
private void emitPushArguments(Name args, int start) {
for (int i = start; i < args.arguments.length; i++) {
emitPushArgument(args, i);
}
}
private void emitPushArgument(Name name, int paramIndex) {
Object arg = name.arguments[paramIndex];
Class<?> ptype = name.function.methodType().parameterType(paramIndex);
emitPushArgument(ptype, arg);
}
private void emitPushArgument(Class<?> ptype, Object arg) {
BasicType bptype = basicType(ptype);
if (arg instanceof Name) {
Name n = (Name) arg;
emitLoadInsn(n.type, n.index());
emitImplicitConversion(n.type, ptype, n);
} else if ((arg == null || arg instanceof String) && bptype == L_TYPE) {
emitConst(arg);
} else {
if (Wrapper.isWrapperType(arg.getClass()) && bptype != L_TYPE) {
emitConst(arg);
} else {
mv.visitLdcInsn(constantPlaceholder(arg));
emitImplicitConversion(L_TYPE, ptype, arg);
}
}
}
/**
* Store the name to its local, if necessary.
*/
private void emitStoreResult(Name name) {
if (name != null && name.type != V_TYPE) {
// non-void: actually assign
emitStoreInsn(name.type, name.index());
}
}
/**
* Emits a return statement from a LF invoker. If required, the result type is cast to the correct return type.
*/
private void emitReturn(Name onStack) {
// return statement
Class<?> rclass = invokerType.returnType();
BasicType rtype = lambdaForm.returnType();
assert(rtype == basicType(rclass)); // must agree
if (rtype == V_TYPE) {
// void
mv.visitInsn(Opcodes.RETURN);
// it doesn't matter what rclass is; the JVM will discard any value
} else {
LambdaForm.Name rn = lambdaForm.names[lambdaForm.result];
// put return value on the stack if it is not already there
if (rn != onStack) {
emitLoadInsn(rtype, lambdaForm.result);
}
emitImplicitConversion(rtype, rclass, rn);
// generate actual return statement
emitReturnInsn(rtype);
}
}
/**
* Emit a type conversion bytecode casting from "from" to "to".
*/
private void emitPrimCast(Wrapper from, Wrapper to) {
// Here's how.
// - indicates forbidden
// <-> indicates implicit
// to ----> boolean byte short char int long float double
// from boolean <-> - - - - - - -
// byte - <-> i2s i2c <-> i2l i2f i2d
// short - i2b <-> i2c <-> i2l i2f i2d
// char - i2b i2s <-> <-> i2l i2f i2d
// int - i2b i2s i2c <-> i2l i2f i2d
// long - l2i,i2b l2i,i2s l2i,i2c l2i <-> l2f l2d
// float - f2i,i2b f2i,i2s f2i,i2c f2i f2l <-> f2d
// double - d2i,i2b d2i,i2s d2i,i2c d2i d2l d2f <->
if (from == to) {
// no cast required, should be dead code anyway
return;
}
if (from.isSubwordOrInt()) {
// cast from {byte,short,char,int} to anything
emitI2X(to);
} else {
// cast from {long,float,double} to anything
if (to.isSubwordOrInt()) {
// cast to {byte,short,char,int}
emitX2I(from);
if (to.bitWidth() < 32) {
// targets other than int require another conversion
emitI2X(to);
}
} else {
// cast to {long,float,double} - this is verbose
boolean error = false;
switch (from) {
case LONG:
switch (to) {
case FLOAT: mv.visitInsn(Opcodes.L2F); break;
case DOUBLE: mv.visitInsn(Opcodes.L2D); break;
default: error = true; break;
}
break;
case FLOAT:
switch (to) {
case LONG : mv.visitInsn(Opcodes.F2L); break;
case DOUBLE: mv.visitInsn(Opcodes.F2D); break;
default: error = true; break;
}
break;
case DOUBLE:
switch (to) {
case LONG : mv.visitInsn(Opcodes.D2L); break;
case FLOAT: mv.visitInsn(Opcodes.D2F); break;
default: error = true; break;
}
break;
default:
error = true;
break;
}
if (error) {
throw new IllegalStateException("unhandled prim cast: " + from + "2" + to);
}
}
}
}
private void emitI2X(Wrapper type) {
switch (type) {
case BYTE: mv.visitInsn(Opcodes.I2B); break;
case SHORT: mv.visitInsn(Opcodes.I2S); break;
case CHAR: mv.visitInsn(Opcodes.I2C); break;
case INT: /* naught */ break;
case LONG: mv.visitInsn(Opcodes.I2L); break;
case FLOAT: mv.visitInsn(Opcodes.I2F); break;
case DOUBLE: mv.visitInsn(Opcodes.I2D); break;
case BOOLEAN:
// For compatibility with ValueConversions and explicitCastArguments:
mv.visitInsn(Opcodes.ICONST_1);
mv.visitInsn(Opcodes.IAND);
break;
default: throw new InternalError("unknown type: " + type);
}
}
private void emitX2I(Wrapper type) {
switch (type) {
case LONG: mv.visitInsn(Opcodes.L2I); break;
case FLOAT: mv.visitInsn(Opcodes.F2I); break;
case DOUBLE: mv.visitInsn(Opcodes.D2I); break;
default: throw new InternalError("unknown type: " + type);
}
}
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