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An unofficial backport of the JDK Classfile API to Java 17
/*
* Copyright (c) 2022, 2024, 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 io.github.dmlloyd.classfile.impl;
import io.github.dmlloyd.classfile.*;
import io.github.dmlloyd.classfile.attribute.CodeAttribute;
import io.github.dmlloyd.classfile.components.ClassPrinter;
import io.github.dmlloyd.classfile.constantpool.ClassEntry;
import io.github.dmlloyd.classfile.constantpool.ModuleEntry;
import io.github.dmlloyd.classfile.constantpool.PoolEntry;
import io.github.dmlloyd.classfile.constantpool.Utf8Entry;
import java.lang.constant.ClassDesc;
import io.github.dmlloyd.classfile.extras.constant.ExtraClassDesc;
import java.lang.constant.MethodTypeDesc;
import io.github.dmlloyd.classfile.extras.constant.ModuleDesc;
import io.github.dmlloyd.classfile.extras.reflect.AccessFlag;
import java.util.AbstractList;
import java.util.Collection;
import java.util.List;
import java.util.function.Consumer;
import java.util.function.Function;
//import jdk.internal.access.SharedSecrets;
//import io.github.dmlloyd.classfile.extras.constant.ClassOrInterfaceDescImpl;
//import jdk.internal.vm.annotation.ForceInline;
//import jdk.internal.vm.annotation.Stable;
import static io.github.dmlloyd.classfile.ClassFile.ACC_STATIC;
import static java.lang.constant.ConstantDescs.CD_double;
import static java.lang.constant.ConstantDescs.CD_long;
import static java.lang.constant.ConstantDescs.CD_void;
/**
* Helper to create and manipulate type descriptors, where type descriptors are
* represented as JVM type descriptor strings and symbols are represented as
* name strings
*/
public class Util {
private Util() {
}
public static Consumer> writingAll(Iterable container) {
record ForEachConsumer(Iterable container) implements Consumer> {
@Override
public void accept(Consumer consumer) {
container.forEach(consumer);
}
}
return new ForEachConsumer<>(container);
}
public static Consumer buildingCode(Consumer codeHandler) {
record WithCodeMethodHandler(Consumer codeHandler) implements Consumer {
@Override
public void accept(MethodBuilder builder) {
builder.withCode(codeHandler);
}
}
return new WithCodeMethodHandler(codeHandler);
}
public static Consumer buildingFlags(int flags) {
record WithFlagFieldHandler(int flags) implements Consumer {
@Override
public void accept(FieldBuilder builder) {
builder.withFlags(flags);
}
}
return new WithFlagFieldHandler(flags);
}
private static final int ATTRIBUTE_STABILITY_COUNT = AttributeMapper.AttributeStability.values().length;
public static boolean isAttributeAllowed(final Attribute attr,
final ClassFileImpl context) {
return attr instanceof BoundAttribute
? ATTRIBUTE_STABILITY_COUNT - attr.attributeMapper().stability().ordinal() > context.attributesProcessingOption().ordinal()
: true;
}
public static int parameterSlots(MethodTypeDesc mDesc) {
int count = mDesc.parameterCount();
for (int i = count - 1; i >= 0; i--) {
if (isDoubleSlot(mDesc.parameterType(i))) {
count++;
}
}
return count;
}
public static int[] parseParameterSlots(int flags, MethodTypeDesc mDesc) {
int[] result = new int[mDesc.parameterCount()];
int count = ((flags & ACC_STATIC) != 0) ? 0 : 1;
for (int i = 0; i < result.length; i++) {
result[i] = count;
count += paramSlotSize(mDesc.parameterType(i));
}
return result;
}
public static int maxLocals(int flags, MethodTypeDesc mDesc) {
return parameterSlots(mDesc) + ((flags & ACC_STATIC) == 0 ? 1 : 0) ;
}
/**
* Converts a descriptor of classes or interfaces into
* a binary name. Rejects primitive types or arrays.
* This is an inverse of {@link ClassDesc#of(String)}.
*/
public static String toBinaryName(ClassDesc cd) {
return toInternalName(cd).replace('/', '.');
}
public static String toInternalName(ClassDesc cd) {
if (cd.isClassOrInterface()) {
String desc = cd.descriptorString();
return desc.substring(1, desc.length() - 1);
}
throw new IllegalArgumentException(cd.descriptorString());
}
public static ClassDesc toClassDesc(String classInternalNameOrArrayDesc) {
return classInternalNameOrArrayDesc.charAt(0) == '['
? ClassDesc.ofDescriptor(classInternalNameOrArrayDesc)
: ExtraClassDesc.ofInternalName(classInternalNameOrArrayDesc);
}
public static List mappedList(List list, Function mapper) {
return new AbstractList<>() {
@Override
public U get(int index) {
return mapper.apply(list.get(index));
}
@Override
public int size() {
return list.size();
}
};
}
public static List entryList(List list) {
var result = new ClassEntry[list.size()]; // null check
for (int i = 0; i < result.length; i++) {
result[i] = TemporaryConstantPool.INSTANCE.classEntry(list.get(i));
}
return List.of(result);
}
public static List moduleEntryList(List list) {
var result = new ModuleEntry[list.size()]; // null check
for (int i = 0; i < result.length; i++) {
result[i] = TemporaryConstantPool.INSTANCE.moduleEntry(TemporaryConstantPool.INSTANCE.utf8Entry(list.get(i).name()));
}
return List.of(result);
}
public static void checkKind(Opcode op, Opcode.Kind k) {
if (op.kind() != k)
throw badOpcodeKindException(op, k);
}
public static IllegalArgumentException badOpcodeKindException(Opcode op, Opcode.Kind k) {
return new IllegalArgumentException(
String.format("Wrong opcode kind specified; found %s(%s), expected %s", op, op.kind(), k));
}
public static int flagsToBits(AccessFlag.Location location, Collection flags) {
int i = 0;
for (AccessFlag f : flags) {
if (!f.locations().contains(location)) {
throw new IllegalArgumentException("unexpected flag: " + f + " use in target location: " + location);
}
i |= f.mask();
}
return i;
}
public static int flagsToBits(AccessFlag.Location location, AccessFlag... flags) {
int i = 0;
for (AccessFlag f : flags) {
if (!f.locations().contains(location)) {
throw new IllegalArgumentException("unexpected flag: " + f + " use in target location: " + location);
}
i |= f.mask();
}
return i;
}
public static boolean has(AccessFlag.Location location, int flagsMask, AccessFlag flag) {
return (flag.mask() & flagsMask) == flag.mask() && flag.locations().contains(location);
}
public static ClassDesc fieldTypeSymbol(Utf8Entry utf8) {
return ((AbstractPoolEntry.Utf8EntryImpl) utf8).fieldTypeSymbol();
}
public static MethodTypeDesc methodTypeSymbol(Utf8Entry utf8) {
return ((AbstractPoolEntry.Utf8EntryImpl) utf8).methodTypeSymbol();
}
@SuppressWarnings("unchecked")
public static > void writeAttribute(BufWriterImpl writer, Attribute attr) {
if (attr instanceof CustomAttribute ca) {
var mapper = (AttributeMapper) ca.attributeMapper();
mapper.writeAttribute(writer, (T) ca);
} else {
assert attr instanceof BoundAttribute || attr instanceof UnboundAttribute;
((Writable) attr).writeTo(writer);
}
}
public static void writeAttributes(BufWriterImpl buf, List> list) {
int size = list.size();
buf.writeU2(size);
for (int i = 0; i < size; i++) {
writeAttribute(buf, list.get(i));
}
}
static void writeList(BufWriterImpl buf, Writable[] array, int size) {
buf.writeU2(size);
for (int i = 0; i < size; i++) {
array[i].writeTo(buf);
}
}
public static int slotSize(ClassDesc desc) {
return desc == CD_void ? 0 : isDoubleSlot(desc) ? 2 : 1;
}
public static int paramSlotSize(ClassDesc desc) {
return isDoubleSlot(desc) ? 2 : 1;
}
public static boolean isDoubleSlot(ClassDesc desc) {
return desc == CD_double || desc == CD_long;
}
public static void dumpMethod(SplitConstantPool cp,
ClassDesc cls,
String methodName,
MethodTypeDesc methodDesc,
int acc,
RawBytecodeHelper.CodeRange bytecode,
Consumer dump) {
// try to dump debug info about corrupted bytecode
try {
var cc = ClassFile.of();
var clm = cc.parse(cc.build(cp.classEntry(cls), cp, clb ->
clb.withMethod(methodName, methodDesc, acc, mb ->
((DirectMethodBuilder) mb).writeAttribute(new UnboundAttribute.AdHocAttribute(Attributes.code()) {
@Override
public void writeBody(BufWriterImpl b) {
b.writeU2U2(-1, -1);//max stack & locals
b.writeInt(bytecode.length());
b.writeBytes(bytecode.array(), 0, bytecode.length());
b.writeU2U2(0, 0);//exception handlers & attributes
}
@Override
public Utf8Entry attributeName() {
return cp.utf8Entry(Attributes.NAME_CODE);
}
}))));
ClassPrinter.toYaml(clm.methods().get(0).code().get(), ClassPrinter.Verbosity.TRACE_ALL, dump);
} catch (Error | Exception __) {
// fallback to bytecode hex dump
dumpBytesHex(dump, bytecode.array(), bytecode.length());
}
}
public static void dumpBytesHex(Consumer dump, byte[] bytes, int length) {
for (int i = 0; i < length; i++) {
if (i % 16 == 0) {
dump.accept("%n%04x:".formatted(i));
}
dump.accept(" %02x".formatted(bytes[i]));
}
}
public static void writeListIndices(BufWriter writer, List list) {
writer.writeU2(list.size());
for (PoolEntry info : list) {
writer.writeIndex(info);
}
}
public static boolean writeLocalVariable(BufWriterImpl buf, PseudoInstruction lvOrLvt) {
return ((WritableLocalVariable) lvOrLvt).writeLocalTo(buf);
}
/**
* A generic interface for objects to write to a
* buf writer. Do not implement unless necessary,
* as this writeTo is public, which can be troublesome.
*/
interface Writable {
void writeTo(BufWriterImpl writer);
}
interface WritableLocalVariable {
boolean writeLocalTo(BufWriterImpl buf);
}
/**
* Returns the hash code of a class or interface L descriptor given the internal name.
*/
public static int descriptorStringHash(int length, int hash) {
if (length > 0xffff)
throw new IllegalArgumentException("String too long: ".concat(Integer.toString(length)));
return 'L' * pow31(length + 1) + hash * 31 + ';';
}
// k is at most 65536, length of Utf8 entry + 1
public static int pow31(int k) {
int r = 1;
// calculate the power contribution from index-th octal digit
// from least to most significant (right to left)
// e.g. decimal 26=octal 32, power(26)=powerOctal(2,0)*powerOctal(3,1)
for (int i = 0; i < SIGNIFICANT_OCTAL_DIGITS; i++) {
r *= powerOctal(k & 7, i);
k >>= 3;
}
return r;
}
// The inverse of 31 in Z/2^32Z* modulo group, a * INVERSE_31 * 31 = a
static final int INVERSE_31 = 0xbdef7bdf;
// k is at most 65536 = octal 200000, only consider 6 octal digits
// Note: 31 powers repeat beyond 1 << 27, only 9 octal digits matter
static final int SIGNIFICANT_OCTAL_DIGITS = 6;
// for base k, storage is k * log_k(N)=k/ln(k) * ln(N)
// k = 2 or 4 is better for space at the cost of more multiplications
/**
* The code below is as if:
* {@snippet lang=java :
* int[] powers = new int[7 * SIGNIFICANT_OCTAL_DIGITS];
*
* for (int i = 1, k = 31; i <= 7; i++, k *= 31) {
* int t = powers[powersIndex(i, 0)] = k;
* for (int j = 1; j < SIGNIFICANT_OCTAL_DIGITS; j++) {
* t *= t;
* t *= t;
* t *= t;
* powers[powersIndex(i, j)] = t;
* }
* }
* }
* This is converted to explicit initialization to avoid bootstrap overhead.
* Validated in UtilTest.
*/
static final int[] powers = new int[] {
0x0000001f, 0x000003c1, 0x0000745f, 0x000e1781, 0x01b4d89f, 0x34e63b41, 0x67e12cdf,
0x94446f01, 0x50a9de01, 0x84304d01, 0x7dd7bc01, 0x8ca02b01, 0xff899a01, 0x25940901,
0x4dbf7801, 0xe3bef001, 0xc1fe6801, 0xe87de001, 0x573d5801, 0x0e3cd001, 0x0d7c4801,
0x54fbc001, 0xb9f78001, 0x2ef34001, 0xb3ef0001, 0x48eac001, 0xede68001, 0xa2e24001,
0x67de0001, 0xcfbc0001, 0x379a0001, 0x9f780001, 0x07560001, 0x6f340001, 0xd7120001,
0x3ef00001, 0x7de00001, 0xbcd00001, 0xfbc00001, 0x3ab00001, 0x79a00001, 0xb8900001,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
static int powersIndex(int digit, int index) {
return (digit - 1) + index * 7;
}
// (31 ^ digit) ^ (8 * index) = 31 ^ (digit * (8 ^ index))
// digit: 0 - 7
// index: 0 - SIGNIFICANT_OCTAL_DIGITS - 1
private static int powerOctal(int digit, int index) {
return digit == 0 ? 1 : powers[powersIndex(digit, index) & 0x3F]; // & 0x3F eliminates bound check
}
}
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