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Upgrade to ASM master (including early support for Java 22 bytecode) 

Closes gh-30845
This commit is contained in:
Juergen Hoeller 2023-07-17 21:17:15 +02:00
parent 3a8b5111d9
commit 0d8a8432d1
8 changed files with 276 additions and 54 deletions
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17
spring-core/src/main/java/org/springframework/asm/ClassReader.java
View File

@ -194,7 +194,7 @@ public class ClassReader {
this.b = classFileBuffer;
// Check the class' major_version. This field is after the magic and minor_version fields, which
// use 4 and 2 bytes respectively.
if (checkClassVersion && readShort(classFileOffset + 6) > Opcodes.V21) {
if (checkClassVersion && readShort(classFileOffset + 6) > Opcodes.V22) {
throw new IllegalArgumentException(
"Unsupported class file major version " + readShort(classFileOffset + 6));
}
@ -2052,6 +2052,7 @@ public class ClassReader {
currentOffset = bytecodeStartOffset;
while (currentOffset < bytecodeEndOffset) {
final int currentBytecodeOffset = currentOffset - bytecodeStartOffset;
readBytecodeInstructionOffset(currentBytecodeOffset);
// Visit the label and the line number(s) for this bytecode offset, if any.
Label currentLabel = labels[currentBytecodeOffset];
@ -2667,6 +2668,20 @@ public class ClassReader {
methodVisitor.visitMaxs(maxStack, maxLocals);
}
/**
* Handles the bytecode offset of the next instruction to be visited in {@link
* #accept(ClassVisitor,int)}. This method is called just before the instruction and before its
* associated label and stack map frame, if any. The default implementation of this method does
* nothing. Subclasses can override this method to store the argument in a mutable field, for
* instance, so that {@link MethodVisitor} instances can get the bytecode offset of each visited
* instruction (if so, the usual concurrency issues related to mutable data should be addressed).
*
* @param bytecodeOffset the bytecode offset of the next instruction to be visited.
*/
protected void readBytecodeInstructionOffset(final int bytecodeOffset) {
// Do nothing by default.
}
/**
* Returns the label corresponding to the given bytecode offset. The default implementation of
* this method creates a label for the given offset if it has not been already created.

1
spring-core/src/main/java/org/springframework/asm/ClassWriter.java
View File

@ -217,6 +217,7 @@ public class ClassWriter extends ClassVisitor {
/**
* Indicates what must be automatically computed in {@link MethodWriter}. Must be one of {@link
* MethodWriter#COMPUTE_NOTHING}, {@link MethodWriter#COMPUTE_MAX_STACK_AND_LOCAL}, {@link
* MethodWriter#COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES}, {@link
* MethodWriter#COMPUTE_INSERTED_FRAMES}, or {@link MethodWriter#COMPUTE_ALL_FRAMES}.
*/
private int compute;

68
spring-core/src/main/java/org/springframework/asm/Frame.java
View File

@ -64,8 +64,8 @@ package org.springframework.asm;
* right shift of {@link #DIM_SHIFT}.
* <li>the KIND field, stored in 4 bits, indicates the kind of VALUE used. These 4 bits can be
* retrieved with {@link #KIND_MASK} and, without any shift, must be equal to {@link
* #CONSTANT_KIND}, {@link #REFERENCE_KIND}, {@link #UNINITIALIZED_KIND}, {@link #LOCAL_KIND}
* or {@link #STACK_KIND}.
* #CONSTANT_KIND}, {@link #REFERENCE_KIND}, {@link #UNINITIALIZED_KIND}, {@link
* #FORWARD_UNINITIALIZED_KIND},{@link #LOCAL_KIND} or {@link #STACK_KIND}.
* <li>the FLAGS field, stored in 2 bits, contains up to 2 boolean flags. Currently only one flag
* is defined, namely {@link #TOP_IF_LONG_OR_DOUBLE_FLAG}.
* <li>the VALUE field, stored in the remaining 20 bits, contains either
@ -78,7 +78,10 @@ package org.springframework.asm;
* <li>the index of a {@link Symbol#TYPE_TAG} {@link Symbol} in the type table of a {@link
* SymbolTable}, if KIND is equal to {@link #REFERENCE_KIND}.
* <li>the index of an {@link Symbol#UNINITIALIZED_TYPE_TAG} {@link Symbol} in the type
* table of a SymbolTable, if KIND is equal to {@link #UNINITIALIZED_KIND}.
* table of a {@link SymbolTable}, if KIND is equal to {@link #UNINITIALIZED_KIND}.
* <li>the index of a {@link Symbol#FORWARD_UNINITIALIZED_TYPE_TAG} {@link Symbol} in the
* type table of a {@link SymbolTable}, if KIND is equal to {@link
* #FORWARD_UNINITIALIZED_KIND}.
* <li>the index of a local variable in the input stack frame, if KIND is equal to {@link
* #LOCAL_KIND}.
* <li>a position relatively to the top of the stack of the input stack frame, if KIND is
@ -88,10 +91,10 @@ package org.springframework.asm;
*
* <p>Output frames can contain abstract types of any kind and with a positive or negative array
* dimension (and even unassigned types, represented by 0 - which does not correspond to any valid
* abstract type value). Input frames can only contain CONSTANT_KIND, REFERENCE_KIND or
* UNINITIALIZED_KIND abstract types of positive or {@literal null} array dimension. In all cases
* the type table contains only internal type names (array type descriptors are forbidden - array
* dimensions must be represented through the DIM field).
* abstract type value). Input frames can only contain CONSTANT_KIND, REFERENCE_KIND,
* UNINITIALIZED_KIND or FORWARD_UNINITIALIZED_KIND abstract types of positive or {@literal null}
* array dimension. In all cases the type table contains only internal type names (array type
* descriptors are forbidden - array dimensions must be represented through the DIM field).
*
* <p>The LONG and DOUBLE types are always represented by using two slots (LONG + TOP or DOUBLE +
* TOP), for local variables as well as in the operand stack. This is necessary to be able to
@ -159,8 +162,9 @@ class Frame {
private static final int CONSTANT_KIND = 1 << KIND_SHIFT;
private static final int REFERENCE_KIND = 2 << KIND_SHIFT;
private static final int UNINITIALIZED_KIND = 3 << KIND_SHIFT;
private static final int LOCAL_KIND = 4 << KIND_SHIFT;
private static final int STACK_KIND = 5 << KIND_SHIFT;
private static final int FORWARD_UNINITIALIZED_KIND = 4 << KIND_SHIFT;
private static final int LOCAL_KIND = 5 << KIND_SHIFT;
private static final int STACK_KIND = 6 << KIND_SHIFT;
// Possible flags for the FLAGS field of an abstract type.
@ -220,13 +224,13 @@ class Frame {
/**
* The abstract types that are initialized in the basic block. A constructor invocation on an
* UNINITIALIZED or UNINITIALIZED_THIS abstract type must replace <i>every occurrence</i> of this
* type in the local variables and in the operand stack. This cannot be done during the first step
* of the algorithm since, during this step, the local variables and the operand stack types are
* still abstract. It is therefore necessary to store the abstract types of the constructors which
* are invoked in the basic block, in order to do this replacement during the second step of the
* algorithm, where the frames are fully computed. Note that this array can contain abstract types
* that are relative to the input locals or to the input stack.
* UNINITIALIZED, FORWARD_UNINITIALIZED or UNINITIALIZED_THIS abstract type must replace <i>every
* occurrence</i> of this type in the local variables and in the operand stack. This cannot be
* done during the first step of the algorithm since, during this step, the local variables and
* the operand stack types are still abstract. It is therefore necessary to store the abstract
* types of the constructors which are invoked in the basic block, in order to do this replacement
* during the second step of the algorithm, where the frames are fully computed. Note that this
* array can contain abstract types that are relative to the input locals or to the input stack.
*/
private int[] initializations;
@ -284,8 +288,12 @@ class Frame {
String descriptor = Type.getObjectType((String) type).getDescriptor();
return getAbstractTypeFromDescriptor(symbolTable, descriptor, 0);
} else {
return UNINITIALIZED_KIND
| symbolTable.addUninitializedType("", ((Label) type).bytecodeOffset);
Label label = (Label) type;
if ((label.flags & Label.FLAG_RESOLVED) != 0) {
return UNINITIALIZED_KIND | symbolTable.addUninitializedType("", label.bytecodeOffset);
} else {
return FORWARD_UNINITIALIZED_KIND | symbolTable.addForwardUninitializedType("", label);
}
}
}
@ -637,12 +645,14 @@ class Frame {
* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
* @param abstractType an abstract type.
* @return the REFERENCE_KIND abstract type corresponding to abstractType if it is
* UNINITIALIZED_THIS or an UNINITIALIZED_KIND abstract type for one of the types on which a
* constructor is invoked in the basic block. Otherwise returns abstractType.
* UNINITIALIZED_THIS or an UNINITIALIZED_KIND or FORWARD_UNINITIALIZED_KIND abstract type for
* one of the types on which a constructor is invoked in the basic block. Otherwise returns
* abstractType.
*/
private int getInitializedType(final SymbolTable symbolTable, final int abstractType) {
if (abstractType == UNINITIALIZED_THIS
|| (abstractType & (DIM_MASK | KIND_MASK)) == UNINITIALIZED_KIND) {
|| (abstractType & (DIM_MASK | KIND_MASK)) == UNINITIALIZED_KIND
|| (abstractType & (DIM_MASK | KIND_MASK)) == FORWARD_UNINITIALIZED_KIND) {
for (int i = 0; i < initializationCount; ++i) {
int initializedType = initializations[i];
int dim = initializedType & DIM_MASK;
@ -1253,11 +1263,12 @@ class Frame {
*
* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
* @param sourceType the abstract type with which the abstract type array element must be merged.
* This type should be of {@link #CONSTANT_KIND}, {@link #REFERENCE_KIND} or {@link
* #UNINITIALIZED_KIND} kind, with positive or {@literal null} array dimensions.
* This type should be of {@link #CONSTANT_KIND}, {@link #REFERENCE_KIND}, {@link
* #UNINITIALIZED_KIND} or {@link #FORWARD_UNINITIALIZED_KIND} kind, with positive or
* {@literal null} array dimensions.
* @param dstTypes an array of abstract types. These types should be of {@link #CONSTANT_KIND},
* {@link #REFERENCE_KIND} or {@link #UNINITIALIZED_KIND} kind, with positive or {@literal
* null} array dimensions.
* {@link #REFERENCE_KIND}, {@link #UNINITIALIZED_KIND} or {@link #FORWARD_UNINITIALIZED_KIND}
* kind, with positive or {@literal null} array dimensions.
* @param dstIndex the index of the type that must be merged in dstTypes.
* @return {@literal true} if the type array has been modified by this operation.
*/
@ -1400,7 +1411,8 @@ class Frame {
*
* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
* @param abstractType an abstract type, restricted to {@link Frame#CONSTANT_KIND}, {@link
* Frame#REFERENCE_KIND} or {@link Frame#UNINITIALIZED_KIND} types.
* Frame#REFERENCE_KIND}, {@link Frame#UNINITIALIZED_KIND} or {@link
* Frame#FORWARD_UNINITIALIZED_KIND} types.
* @param output where the abstract type must be put.
* @see <a href="https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.4">JVMS
* 4.7.4</a>
@ -1422,6 +1434,10 @@ class Frame {
case UNINITIALIZED_KIND:
output.putByte(ITEM_UNINITIALIZED).putShort((int) symbolTable.getType(typeValue).data);
break;
case FORWARD_UNINITIALIZED_KIND:
output.putByte(ITEM_UNINITIALIZED);
symbolTable.getForwardUninitializedLabel(typeValue).put(output);
break;
default:
throw new AssertionError();
}

48
spring-core/src/main/java/org/springframework/asm/Label.java
View File

@ -81,6 +81,9 @@ public class Label {
/** A flag indicating that the basic block corresponding to a label is the end of a subroutine. */
static final int FLAG_SUBROUTINE_END = 64;
/** A flag indicating that this label has at least one associated line number. */
static final int FLAG_LINE_NUMBER = 128;
/**
* The number of elements to add to the {@link #otherLineNumbers} array when it needs to be
* resized to store a new source line number.
@ -113,6 +116,13 @@ public class Label {
*/
static final int FORWARD_REFERENCE_TYPE_WIDE = 0x20000000;
/**
* The type of forward references stored in two bytes in the <i>stack map table</i>. This is the
* case of the labels of {@link Frame#ITEM_UNINITIALIZED} stack map frame elements, when the NEW
* instruction is after the &lt;init&gt; constructor call (in bytecode offset order).
*/
static final int FORWARD_REFERENCE_TYPE_STACK_MAP = 0x30000000;
/**
* The bit mask to extract the 'handle' of a forward reference to this label. The extracted handle
* is the bytecode offset where the forward reference value is stored (using either 2 or 4 bytes,
@ -145,9 +155,9 @@ public class Label {
short flags;
/**
* The source line number corresponding to this label, or 0. If there are several source line
* numbers corresponding to this label, the first one is stored in this field, and the remaining
* ones are stored in {@link #otherLineNumbers}.
* The source line number corresponding to this label, if {@link #FLAG_LINE_NUMBER} is set. If
* there are several source line numbers corresponding to this label, the first one is stored in
* this field, and the remaining ones are stored in {@link #otherLineNumbers}.
*/
private short lineNumber;
@ -332,7 +342,8 @@ public class Label {
* @param lineNumber a source line number (which should be strictly positive).
*/
final void addLineNumber(final int lineNumber) {
if (this.lineNumber == 0) {
if ((flags & FLAG_LINE_NUMBER) == 0) {
flags |= FLAG_LINE_NUMBER;
this.lineNumber = (short) lineNumber;
} else {
if (otherLineNumbers == null) {
@ -356,7 +367,7 @@ public class Label {
*/
final void accept(final MethodVisitor methodVisitor, final boolean visitLineNumbers) {
methodVisitor.visitLabel(this);
if (visitLineNumbers && lineNumber != 0) {
if (visitLineNumbers && (flags & FLAG_LINE_NUMBER) != 0) {
methodVisitor.visitLineNumber(lineNumber & 0xFFFF, this);
if (otherLineNumbers != null) {
for (int i = 1; i <= otherLineNumbers[0]; ++i) {
@ -400,6 +411,20 @@ public class Label {
}
}
/**
* Puts a reference to this label in the <i>stack map table</i> of a method. If the bytecode
* offset of the label is known, it is written directly. Otherwise, a null relative offset is
* written and a new forward reference is declared for this label.
*
* @param stackMapTableEntries the stack map table where the label offset must be added.
*/
final void put(final ByteVector stackMapTableEntries) {
if ((flags & FLAG_RESOLVED) == 0) {
addForwardReference(0, FORWARD_REFERENCE_TYPE_STACK_MAP, stackMapTableEntries.length);
}
stackMapTableEntries.putShort(bytecodeOffset);
}
/**
* Adds a forward reference to this label. This method must be called only for a true forward
* reference, i.e. only if this label is not resolved yet. For backward references, the relative
@ -432,9 +457,12 @@ public class Label {
* Sets the bytecode offset of this label to the given value and resolves the forward references
* to this label, if any. This method must be called when this label is added to the bytecode of
* the method, i.e. when its bytecode offset becomes known. This method fills in the blanks that
* where left in the bytecode by each forward reference previously added to this label.
* where left in the bytecode (and optionally in the stack map table) by each forward reference
* previously added to this label.
*
* @param code the bytecode of the method.
* @param stackMapTableEntries the 'entries' array of the StackMapTable code attribute of the
* method. Maybe {@literal null}.
* @param bytecodeOffset the bytecode offset of this label.
* @return {@literal true} if a blank that was left for this label was too small to store the
* offset. In such a case the corresponding jump instruction is replaced with an equivalent
@ -442,7 +470,8 @@ public class Label {
* instructions are later replaced with standard bytecode instructions with wider offsets (4
* bytes instead of 2), in ClassReader.
*/
final boolean resolve(final byte[] code, final int bytecodeOffset) {
final boolean resolve(
final byte[] code, final ByteVector stackMapTableEntries, final int bytecodeOffset) {
this.flags |= FLAG_RESOLVED;
this.bytecodeOffset = bytecodeOffset;
if (forwardReferences == null) {
@ -472,11 +501,14 @@ public class Label {
}
code[handle++] = (byte) (relativeOffset >>> 8);
code[handle] = (byte) relativeOffset;
} else {
} else if ((reference & FORWARD_REFERENCE_TYPE_MASK) == FORWARD_REFERENCE_TYPE_WIDE) {
code[handle++] = (byte) (relativeOffset >>> 24);
code[handle++] = (byte) (relativeOffset >>> 16);
code[handle++] = (byte) (relativeOffset >>> 8);
code[handle] = (byte) relativeOffset;
} else {
stackMapTableEntries.data[handle++] = (byte) (bytecodeOffset >>> 8);
stackMapTableEntries.data[handle] = (byte) bytecodeOffset;
}
}
return hasAsmInstructions;

14
spring-core/src/main/java/org/springframework/asm/MethodWriter.java
View File

@ -534,8 +534,9 @@ final class MethodWriter extends MethodVisitor {
* the number of stack elements. The local variables start at index 3 and are followed by the
* operand stack elements. In summary frame[0] = offset, frame[1] = numLocal, frame[2] = numStack.
* Local variables and operand stack entries contain abstract types, as defined in {@link Frame},
* but restricted to {@link Frame#CONSTANT_KIND}, {@link Frame#REFERENCE_KIND} or {@link
* Frame#UNINITIALIZED_KIND} abstract types. Long and double types use only one array entry.
* but restricted to {@link Frame#CONSTANT_KIND}, {@link Frame#REFERENCE_KIND}, {@link
* Frame#UNINITIALIZED_KIND} or {@link Frame#FORWARD_UNINITIALIZED_KIND} abstract types. Long and
* double types use only one array entry.
*/
private int[] currentFrame;
@ -1199,7 +1200,7 @@ final class MethodWriter extends MethodVisitor {
@Override
public void visitLabel(final Label label) {
// Resolve the forward references to this label, if any.
hasAsmInstructions |= label.resolve(code.data, code.length);
hasAsmInstructions |= label.resolve(code.data, stackMapTableEntries, code.length);
// visitLabel starts a new basic block (except for debug only labels), so we need to update the
// previous and current block references and list of successors.
if ((label.flags & Label.FLAG_DEBUG_ONLY) != 0) {
@ -1795,7 +1796,7 @@ final class MethodWriter extends MethodVisitor {
if (compute == COMPUTE_ALL_FRAMES) {
Label nextBasicBlock = new Label();
nextBasicBlock.frame = new Frame(nextBasicBlock);
nextBasicBlock.resolve(code.data, code.length);
nextBasicBlock.resolve(code.data, stackMapTableEntries, code.length);
lastBasicBlock.nextBasicBlock = nextBasicBlock;
lastBasicBlock = nextBasicBlock;
currentBasicBlock = null;
@ -1979,9 +1980,8 @@ final class MethodWriter extends MethodVisitor {
.putByte(Frame.ITEM_OBJECT)
.putShort(symbolTable.addConstantClass((String) type).index);
} else {
stackMapTableEntries
.putByte(Frame.ITEM_UNINITIALIZED)
.putShort(((Label) type).bytecodeOffset);
stackMapTableEntries.putByte(Frame.ITEM_UNINITIALIZED);
((Label) type).put(stackMapTableEntries);
}
}

1
spring-core/src/main/java/org/springframework/asm/Opcodes.java
View File

@ -286,6 +286,7 @@ public interface Opcodes {
int V19 = 0 << 16 | 63;
int V20 = 0 << 16 | 64;
int V21 = 0 << 16 | 65;
int V22 = 0 << 16 | 66;
/**
* Version flag indicating that the class is using 'preview' features.

24
spring-core/src/main/java/org/springframework/asm/Symbol.java
View File

@ -103,12 +103,25 @@ abstract class Symbol {
static final int TYPE_TAG = 128;
/**
* The tag value of an {@link Frame#ITEM_UNINITIALIZED} type entry in the type table of a class.
* The tag value of an uninitialized type entry in the type table of a class. This type is used
* for the normal case where the NEW instruction is before the &lt;init&gt; constructor call (in
* bytecode offset order), i.e. when the label of the NEW instruction is resolved when the
* constructor call is visited. If the NEW instruction is after the constructor call, use the
* {@link #FORWARD_UNINITIALIZED_TYPE_TAG} tag value instead.
*/
static final int UNINITIALIZED_TYPE_TAG = 129;
/**
* The tag value of an uninitialized type entry in the type table of a class. This type is used
* for the unusual case where the NEW instruction is after the &lt;init&gt; constructor call (in
* bytecode offset order), i.e. when the label of the NEW instruction is not resolved when the
* constructor call is visited. If the NEW instruction is before the constructor call, use the
* {@link #UNINITIALIZED_TYPE_TAG} tag value instead.
*/
static final int FORWARD_UNINITIALIZED_TYPE_TAG = 130;
/** The tag value of a merged type entry in the (ASM specific) type table of a class. */
static final int MERGED_TYPE_TAG = 130;
static final int MERGED_TYPE_TAG = 131;
// Instance fields.
@ -151,8 +164,8 @@ abstract class Symbol {
* #CONSTANT_INVOKE_DYNAMIC_TAG} symbols,
* <li>an arbitrary string for {@link #CONSTANT_UTF8_TAG} and {@link #CONSTANT_STRING_TAG}
* symbols,
* <li>an internal class name for {@link #CONSTANT_CLASS_TAG}, {@link #TYPE_TAG} and {@link
* #UNINITIALIZED_TYPE_TAG} symbols,
* <li>an internal class name for {@link #CONSTANT_CLASS_TAG}, {@link #TYPE_TAG}, {@link
* #UNINITIALIZED_TYPE_TAG} and {@link #FORWARD_UNINITIALIZED_TYPE_TAG} symbols,
* <li>{@literal null} for the other types of symbol.
* </ul>
*/
@ -172,6 +185,9 @@ abstract class Symbol {
* {@link #CONSTANT_DYNAMIC_TAG} or {@link #BOOTSTRAP_METHOD_TAG} symbols,
* <li>the bytecode offset of the NEW instruction that created an {@link
* Frame#ITEM_UNINITIALIZED} type for {@link #UNINITIALIZED_TYPE_TAG} symbols,
* <li>the index of the {@link Label} (in the {@link SymbolTable#labelTable} table) of the NEW
* instruction that created an {@link Frame#ITEM_UNINITIALIZED} type for {@link
* #FORWARD_UNINITIALIZED_TYPE_TAG} symbols,
* <li>the indices (in the class' type table) of two {@link #TYPE_TAG} source types for {@link
* #MERGED_TYPE_TAG} symbols,
* <li>0 for the other types of symbol.

157
spring-core/src/main/java/org/springframework/asm/SymbolTable.java
View File

@ -108,11 +108,35 @@ final class SymbolTable {
* An ASM specific type table used to temporarily store internal names that will not necessarily
* be stored in the constant pool. This type table is used by the control flow and data flow
* analysis algorithm used to compute stack map frames from scratch. This array stores {@link
* Symbol#TYPE_TAG} and {@link Symbol#UNINITIALIZED_TYPE_TAG}) Symbol. The type symbol at index
* {@code i} has its {@link Symbol#index} equal to {@code i} (and vice versa).
* Symbol#TYPE_TAG}, {@link Symbol#UNINITIALIZED_TYPE_TAG},{@link
* Symbol#FORWARD_UNINITIALIZED_TYPE_TAG} and {@link Symbol#MERGED_TYPE_TAG} entries. The type
* symbol at index {@code i} has its {@link Symbol#index} equal to {@code i} (and vice versa).
*/
private Entry[] typeTable;
/**
* The actual number of {@link LabelEntry} in {@link #labelTable}. These elements are stored from
* index 0 to labelCount (excluded). The other array entries are empty. These label entries are
* also stored in the {@link #labelEntries} hash set.
*/
private int labelCount;
/**
* The labels corresponding to the "forward uninitialized" types in the ASM specific {@link
* typeTable} (see {@link Symbol#FORWARD_UNINITIALIZED_TYPE_TAG}). The label entry at index {@code
* i} has its {@link LabelEntry#index} equal to {@code i} (and vice versa).
*/
private LabelEntry[] labelTable;
/**
* A hash set of all the {@link LabelEntry} elements in the {@link #labelTable}. Each {@link
* LabelEntry} instance is stored at the array index given by its hash code modulo the array size.
* If several entries must be stored at the same array index, they are linked together via their
* {@link LabelEntry#next} field. The {@link #getOrAddLabelEntry(Label)} method ensures that this
* table does not contain duplicated entries.
*/
private LabelEntry[] labelEntries;
/**
* Constructs a new, empty SymbolTable for the given ClassWriter.
*
@ -1129,6 +1153,18 @@ final class SymbolTable {
return typeTable[typeIndex];
}
/**
* Returns the label corresponding to the "forward uninitialized" type table element whose index
* is given.
*
* @param typeIndex the type table index of a "forward uninitialized" type table element.
* @return the label corresponding of the NEW instruction which created this "forward
* uninitialized" type.
*/
Label getForwardUninitializedLabel(final int typeIndex) {
return labelTable[(int) typeTable[typeIndex].data].label;
}
/**
* Adds a type in the type table of this symbol table. Does nothing if the type table already
* contains a similar type.
@ -1149,13 +1185,13 @@ final class SymbolTable {
}
/**
* Adds an {@link Frame#ITEM_UNINITIALIZED} type in the type table of this symbol table. Does
* nothing if the type table already contains a similar type.
* Adds an uninitialized type in the type table of this symbol table. Does nothing if the type
* table already contains a similar type.
*
* @param value an internal class name.
* @param bytecodeOffset the bytecode offset of the NEW instruction that created this {@link
* Frame#ITEM_UNINITIALIZED} type value.
* @return the index of a new or already existing type Symbol with the given value.
* @param bytecodeOffset the bytecode offset of the NEW instruction that created this
* uninitialized type value.
* @return the index of a new or already existing type #@link Symbol} with the given value.
*/
int addUninitializedType(final String value, final int bytecodeOffset) {
int hashCode = hash(Symbol.UNINITIALIZED_TYPE_TAG, value, bytecodeOffset);
@ -1173,6 +1209,32 @@ final class SymbolTable {
new Entry(typeCount, Symbol.UNINITIALIZED_TYPE_TAG, value, bytecodeOffset, hashCode));
}
/**
* Adds a "forward uninitialized" type in the type table of this symbol table. Does nothing if the
* type table already contains a similar type.
*
* @param value an internal class name.
* @param label the label of the NEW instruction that created this uninitialized type value. If
* the label is resolved, use the {@link #addUninitializedType} method instead.
* @return the index of a new or already existing type {@link Symbol} with the given value.
*/
int addForwardUninitializedType(final String value, final Label label) {
int labelIndex = getOrAddLabelEntry(label).index;
int hashCode = hash(Symbol.FORWARD_UNINITIALIZED_TYPE_TAG, value, labelIndex);
Entry entry = get(hashCode);
while (entry != null) {
if (entry.tag == Symbol.FORWARD_UNINITIALIZED_TYPE_TAG
&& entry.hashCode == hashCode
&& entry.data == labelIndex
&& entry.value.equals(value)) {
return entry.index;
}
entry = entry.next;
}
return addTypeInternal(
new Entry(typeCount, Symbol.FORWARD_UNINITIALIZED_TYPE_TAG, value, labelIndex, hashCode));
}
/**
* Adds a merged type in the type table of this symbol table. Does nothing if the type table
* already contains a similar type.
@ -1225,6 +1287,59 @@ final class SymbolTable {
return put(entry).index;
}
/**
* Returns the {@link LabelEntry} corresponding to the given label. Creates a new one if there is
* no such entry.
*
* @param label the {@link Label} of a NEW instruction which created an uninitialized type, in the
* case where this NEW instruction is after the &lt;init&gt; constructor call (in bytecode
* offset order). See {@link Symbol#FORWARD_UNINITIALIZED_TYPE_TAG}.
* @return the {@link LabelEntry} corresponding to {@code label}.
*/
private LabelEntry getOrAddLabelEntry(final Label label) {
if (labelEntries == null) {
labelEntries = new LabelEntry[16];
labelTable = new LabelEntry[16];
}
int hashCode = System.identityHashCode(label);
LabelEntry labelEntry = labelEntries[hashCode % labelEntries.length];
while (labelEntry != null && labelEntry.label != label) {
labelEntry = labelEntry.next;
}
if (labelEntry != null) {
return labelEntry;
}
if (labelCount > (labelEntries.length * 3) / 4) {
int currentCapacity = labelEntries.length;
int newCapacity = currentCapacity * 2 + 1;
LabelEntry[] newLabelEntries = new LabelEntry[newCapacity];
for (int i = currentCapacity - 1; i >= 0; --i) {
LabelEntry currentEntry = labelEntries[i];
while (currentEntry != null) {
int newCurrentEntryIndex = System.identityHashCode(currentEntry.label) % newCapacity;
LabelEntry nextEntry = currentEntry.next;
currentEntry.next = newLabelEntries[newCurrentEntryIndex];
newLabelEntries[newCurrentEntryIndex] = currentEntry;
currentEntry = nextEntry;
}
}
labelEntries = newLabelEntries;
}
if (labelCount == labelTable.length) {
LabelEntry[] newLabelTable = new LabelEntry[2 * labelTable.length];
System.arraycopy(labelTable, 0, newLabelTable, 0, labelTable.length);
labelTable = newLabelTable;
}
labelEntry = new LabelEntry(labelCount, label);
int index = hashCode % labelEntries.length;
labelEntry.next = labelEntries[index];
labelEntries[index] = labelEntry;
labelTable[labelCount++] = labelEntry;
return labelEntry;
}
// -----------------------------------------------------------------------------------------------
// Static helper methods to compute hash codes.
// -----------------------------------------------------------------------------------------------
@ -1275,7 +1390,7 @@ final class SymbolTable {
*
* @author Eric Bruneton
*/
private static class Entry extends Symbol {
private static final class Entry extends Symbol {
/** The hash code of this entry. */
final int hashCode;
@ -1319,4 +1434,30 @@ final class SymbolTable {
this.hashCode = hashCode;
}
}
/**
* A label corresponding to a "forward uninitialized" type in the ASM specific {@link
* SymbolTable#typeTable} (see {@link Symbol#FORWARD_UNINITIALIZED_TYPE_TAG}).
*
* @author Eric Bruneton
*/
private static final class LabelEntry {
/** The index of this label entry in the {@link SymbolTable#labelTable} array. */
final int index;
/** The value of this label entry. */
final Label label;
/**
* Another entry (and so on recursively) having the same hash code (modulo the size of {@link
* SymbolTable#labelEntries}}) as this one.
*/
LabelEntry next;
LabelEntry(final int index, final Label label) {
this.index = index;
this.label = label;
}
}
}