Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.impl.services.bytecode.BCMethod

Modifier and Type	Field and Description
pack-priv final BCClass	cb
pack-priv static final int	CODE_SPLIT_LENGTH Code length at which to split into sub-methods.
private Conditional	condition
private int	currentVarNum
private boolean	handlingOverflow True if we are currently switching control over to a sub method to avoid hitting the code generation limit of 65535 bytes per method.
pack-priv int	maxStack Maximum stack depth seen in this method, measured in words.
protected final ClassHolder	modClass
pack-priv CodeChunk	myCode
protected ClassMember	myEntry
private final String	myName The original name of the method, this represents how any user would call this method.
pack-priv final String	myReturnType
private static final byte[]	newArrayElementTypeMap this array maps the BCExpr vm_* constants 0..6 to the expected VM type constants for the newarray instruction.
pack-priv BCLocalField[]	parameters Fast access for the parametes, will be null if the method has no parameters.
private final String[]	parameterTypes List of parameter types with java language class names.
private int	stackDepth Current stack depth in this method, measured in words.
private int	stackTypeOffset Points to the next array offset in stackTypes to be used.
private Type[]	stackTypes Array of the current types of the values on the stack.
private int	statementNum
private int	subMethodCount How many sub-methods we have overflowed to.
pack-priv static final byte	T_BOOLEAN
pack-priv Vector<String>	thrownExceptions

Access	Constructor and Description
pack-priv	BCMethod(ClassBuilder cb, String returnType, String methodName, int modifiers, String[] parms, BCJava factory)

Method Summary

Modifier and Type	Method and Description
private void	addInstrCPE(short opcode, int cpe) Write a instruction that uses a constant pool entry as an operand, add a limit exceeded message if the number of constant pool entries has exceeded the limit.
public void	addThrownException(String exceptionClass) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.addThrownException. a throwable can be added to the end of the list of thrownExceptions.
public int	callMethod(Object methodDescriptor) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.callMethod. Call a method previously described by describeMethod().
public int	callMethod(short type of method invocation opcode, String Class or interface the method is declared in. If it is a non-static method call then if declaringClass is null, the declared type is taken to be the type of the reference that will be popped. declaringClass, String name of the method methodName, String class name or primitive type (including "void") of the return type of the method, can not be null. returnType, int number of arguments to the method (can be 0). numArgs) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.callMethod. Call a method.
pack-priv final void	callSubMethod(BCMethod subMethod) Call a sub-method created by getNewSubMethod handling parameters correctly.
public void	callSuper() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.callSuper. Call super().
public void	cast(String type (primitive, interface or class) to cast to. className) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.cast. Cast the top stack value.
public void	complete() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.complete. when the method has had all of its parameters and thrown exceptions defined, and its statement block has been completed, it can be completed and its class file information generated.
public void	completeConditional() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.completeConditional. Complete a conditional which completes the false code path.
public void	conditionalIf() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.conditionalIf. Initiate a conditional sequence.
private void	conditionalIf(short opcode)
public void	conditionalIfNull() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.conditionalIfNull. Initiate a conditional sequence.
pack-priv ClassHolder	constantPool() In their giveCode methods, the parts of the method body will want to get to the constant pool to add their constants.
private Type[]	copyStack()
public Object	describeMethod(short opcode, String declaringClass, String methodName, String returnType) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.describeMethod. Return an object that efficiently (to the implementation) describes a zero-argument method and can be used with the single argument callMethod().
public void	dup() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.dup. Duplicate the top value on the stack.
public void	endStatement() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.endStatement. End a statement.
public void	getArrayElement(int Offset into the array (zero based) element) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getArrayElement. Pop an array refrence off the stack and push an element from that array.
public void	getField(LocalField field) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getField. Push the contents of the local field onto the stack.
public void	getField(String declaringClass, String fieldName, String fieldType) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getField. Push the contents of the described field onto the stack.
private void	getField(short opcode, String declaringClass, String fieldName, String fieldType)
public String	getName() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getName. Return the logical name of the method.
pack-priv final BCMethod	Returns: A valid empty sub method. getNewSubMethod(String Return type of the new method returnType, boolean True to define the method with matching parameters false to define it with no parameters. withParameters) Create a sub-method from this method to allow the code builder to split a single logical method into multiple methods to avoid the 64k per-method code size limit.
public void	getParameter(int position of the parameter (zero based). id) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getParameter. Push a parameter value.
public void	getStaticField(String declaringClass, String fieldName, String fieldType) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getStaticField. Push the contents of the described static field onto the stack.
private void	growStack(int size, Type type)
private void	growStack(Type type)
public void	isInstanceOf(String className) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.isInstanceOf. Pop the top stack value and push a boolean that is the result of an instanceof check on the popped reference.
public void	methodReturn() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.methodReturn. Return from a method, optionally with a value.
private void	overflowMethodCheck() Check to see if the current method byte code is nearing the limit of 65535.
public void	pop() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pop. Pop the top value off the stack Stack ..., value => ...
private Type	popStack()
public void	push(byte value) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push. Push a byte constant onto the stack Stack ...
public void	push(boolean value) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push. Push a boolean constant onto the stack Stack ...
public void	push(short value) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push. Push a short constant onto the stack Stack ...
public void	push(int value) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push. Push a int constant onto the stack Stack ...
private void	push(int Value to be pushed value, Type Final type of the value. type) Push an integer value.
public void	push(long value) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push. Push a long value onto the stack.
public void	push(float value) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push. Push a float constant onto the stack Stack ...
public void	push(double value) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push. Push a double constant onto the stack Stack ...
public void	push(String value) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push. Push a String constant onto the stack Stack ...
public void	pushNewArray(String - type of array. className, int - number of elements in the array size) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pushNewArray. Create an array instance Stack ...
public void	pushNewComplete(int number of arguments to the constructor (can be 0). numArgs) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pushNewComplete. Complete the sequence that was started with pushNewStart().
public void	pushNewStart(String class name of object to be created. className) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pushNewStart. Initiate a sequence that calls a constructor, equivalent to the new operator in Java.
public void	pushNull(String type) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pushNull. Push a typed null onto the stack Stack ...
public void	pushThis() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pushThis. Push this onto the stack.
public void	putField(LocalField field) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.putField. Upon entry the top word(s) on the stack is the value to be put into the field.
public void	putField(String fieldName, String fieldType) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.putField. Pop the top stack value and store it in the instance field of this class.
private void	putField(Type fieldType, int cpi, boolean dup)
public void	putField(String declaringClass, String fieldName, String fieldType) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.putField. Pop the top stack value and store it in the field.
public void	setArrayElement(int Offset into the array (zero based) element) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.setArrayElement. Pop an array reference off the stack, store a value in the array at the passed in offset.
public void	setField(LocalField field) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.setField. Set the field but don't duplicate its value so nothing is left on the stack after this call.
private void	splitMethod() Attempt to split a large method by pushing code out to several sub-methods.
public void	startElseCode() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.startElseCode. Complete the true code path of a conditional.
public boolean	statementNumHitLimit(int noStatementsAdded) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.statementNumHitLimit. Tell if statement number in this method builder hits limit.
public void	swap() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.swap. Swap the top two values on the stack.
public void	upCast(String className) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.upCast. Upcast the top stack value.
private Type	vmNameDeclaringClass(String declaringClass)
protected void	writeExceptions() sets exceptionBytes to the attribute_info needed for a method's Exceptions attribute.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

cb	back to summary
pack-priv final BCClass cb

CODE_SPLIT_LENGTH	back to summary
pack-priv static final int CODE_SPLIT_LENGTH Code length at which to split into sub-methods. Normally set to the maximim code length the JVM can support, but for testing the split code it can be reduced so that the standard tests cause some splitting. Tested with value set to 2000.

condition	back to summary
private Conditional condition

currentVarNum	back to summary
private int currentVarNum

handlingOverflow	back to summary
private boolean handlingOverflow True if we are currently switching control over to a sub method to avoid hitting the code generation limit of 65535 bytes per method.

maxStack	back to summary
pack-priv int maxStack Maximum stack depth seen in this method, measured in words. Corresponds to max_stack in the Code attribute of section 4.7.3 of the vm spec.

modClass	back to summary
protected final ClassHolder modClass

myCode	back to summary
pack-priv CodeChunk myCode

myEntry	back to summary
protected ClassMember myEntry

myName	back to summary
private final String myName The original name of the method, this represents how any user would call this method.

myReturnType	back to summary
pack-priv final String myReturnType

newArrayElementTypeMap	back to summary
private static final byte[] newArrayElementTypeMap this array maps the BCExpr vm_* constants 0..6 to the expected VM type constants for the newarray instruction. Because boolean was mapped to integer for general instructions, it will have to be specially matched and mapped to its value directly (4).

parameters	back to summary
pack-priv BCLocalField[] parameters Fast access for the parametes, will be null if the method has no parameters.

parameterTypes	back to summary
private final String[] parameterTypes List of parameter types with java language class names. Can be null or zero length for no parameters.

stackDepth	back to summary
private int stackDepth Current stack depth in this method, measured in words.

stackTypeOffset	back to summary
private int stackTypeOffset Points to the next array offset in stackTypes to be used. Really it's the number of valid entries in stackTypes.

stackTypes	back to summary
private Type[] stackTypes Array of the current types of the values on the stack. A type that types up two words on the stack, e.g. double will only occupy one element in this array. This array is dynamically re-sized as needed.

statementNum	back to summary
private int statementNum

subMethodCount	back to summary
private int subMethodCount How many sub-methods we have overflowed to.

T_BOOLEAN	back to summary
pack-priv static final byte T_BOOLEAN

thrownExceptions	back to summary
pack-priv Vector<String> thrownExceptions

BCMethod	back to summary
pack-priv BCMethod(ClassBuilder cb, String returnType, String methodName, int modifiers, String[] parms, BCJava factory)

Method Detail

addInstrCPE	back to summary
private void addInstrCPE(short opcode, int cpe) Write a instruction that uses a constant pool entry as an operand, add a limit exceeded message if the number of constant pool entries has exceeded the limit.

addThrownException	back to summary
public void addThrownException(String exceptionClass) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.addThrownException. a throwable can be added to the end of the list of thrownExceptions.

addThrownException

back to summary

public void addThrownException(String exceptionClass)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.addThrownException.

a throwable can be added to the end of the list of thrownExceptions.

callMethod	back to summary
public int callMethod(Object methodDescriptor) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.callMethod. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.callMethod. Call a method previously described by describeMethod(). static methods Stack ...,value* => [numArgs number of values will be popped] ...,return_value [void methods will not push a value] non-static methods Stack ...,ref,value* => [numArgs number of values will be popped] ...,return_value [void methods will not push a value]

callMethod

back to summary

public int callMethod(Object methodDescriptor)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.callMethod.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.callMethod.

Call a method previously described by describeMethod().

static methods

Stack ...,value* => [numArgs number of values will be popped]
      ...,return_value [void methods will not push a value]

non-static methods

Stack ...,ref,value* => [numArgs number of values will be popped]
      ...,return_value [void methods will not push a value]

callMethod	back to summary
public int callMethod(short opcode, String declaringClass, String methodName, String returnType, int numArgs) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.callMethod. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.callMethod. Call a method. The instance (receiver or reference) for non-static methods must be pushed by the caller. The instance (for non-static) and the arguments are popped of the stack, and the return value (if any) is pushed onto the stack. The type needs to be one of: VMOpcode.INVOKESTATIC - call a static method VMOpcode.INVOKEVIRTUAL - call method declared in the class or super-class. VMOpcode.INVOKEINTERFACE - call a method declared in an interface static methods Stack ...,value* => [numArgs number of values will be popped] ...,return_value [void methods will not push a value] non-static methods Stack ...,ref,value* => [numArgs number of values will be popped] ...,return_value [void methods will not push a value] The type of the arguments to the methods must exactly match the declared types of the parameters to the methods. If a argument is of the incorrect type the caller must up cast it or down cast it. Parameters opcode:short type of method invocation declaringClass:String Class or interface the method is declared in. If it is a non-static method call then if declaringClass is null, the declared type is taken to be the type of the reference that will be popped. methodName:String name of the method returnType:String class name or primitive type (including "void") of the return type of the method, can not be null. numArgs:int number of arguments to the method (can be 0).

callMethod

back to summary

public int callMethod(short opcode, String declaringClass, String methodName, String returnType, int numArgs)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.callMethod.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.callMethod.

Call a method. The instance (receiver or reference) for non-static methods must be pushed by the caller. The instance (for non-static) and the arguments are popped of the stack, and the return value (if any) is pushed onto the stack.
The type needs to be one of:

VMOpcode.INVOKESTATIC - call a static method
VMOpcode.INVOKEVIRTUAL - call method declared in the class or super-class.
VMOpcode.INVOKEINTERFACE - call a method declared in an interface

static methods

Stack ...,value* => [numArgs number of values will be popped]
      ...,return_value [void methods will not push a value]

non-static methods

Stack ...,ref,value* => [numArgs number of values will be popped]
      ...,return_value [void methods will not push a value]

The type of the arguments to the methods must exactly match the declared types of the parameters to the methods. If a argument is of the incorrect type the caller must up cast it or down cast it.

Parameters

opcode:short: type of method invocation
declaringClass:String: Class or interface the method is declared in. If it is a non-static method call then if declaringClass is null, the declared type is taken to be the type of the reference that will be popped.
methodName:String: name of the method
returnType:String: class name or primitive type (including "void") of the return type of the method, can not be null.
numArgs:int: number of arguments to the method (can be 0).

callSubMethod	back to summary
pack-priv final void callSubMethod(BCMethod subMethod) Call a sub-method created by getNewSubMethod handling parameters correctly.

callSuper	back to summary
public void callSuper() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.callSuper. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.callSuper. Call super(). Caller must only add this to a constructor. Stack ... => ...

callSuper

back to summary

public void callSuper()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.callSuper.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.callSuper.

Call super(). Caller must only add this to a constructor.


Stack ... =>
      ...

cast	back to summary
public void cast(String className) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.cast. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.cast. Cast the top stack value. Correctly down-casts a reference or casts a primitive type (e.g. int to short). Stack ...,value => ...,cast_value Parameters className:String type (primitive, interface or class) to cast to.

cast

back to summary

public void cast(String className)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.cast.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.cast.

Cast the top stack value. Correctly down-casts a reference or casts a primitive type (e.g. int to short).

Stack ...,value =>
      ...,cast_value

Parameters

className:String: type (primitive, interface or class) to cast to.

complete	back to summary
public void complete() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.complete. when the method has had all of its parameters and thrown exceptions defined, and its statement block has been completed, it can be completed and its class file information generated. further alterations of the method will not be reflected in the code generated for it.

complete

back to summary

public void complete()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.complete.

when the method has had all of its parameters and thrown exceptions defined, and its statement block has been completed, it can be completed and its class file information generated.

further alterations of the method will not be reflected in the code generated for it.

completeConditional	back to summary
public void completeConditional() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.completeConditional. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.completeConditional. Complete a conditional which completes the false code path.

completeConditional

back to summary

public void completeConditional()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.completeConditional.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.completeConditional.

Complete a conditional which completes the false code path.

conditionalIf	back to summary
public void conditionalIf() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.conditionalIf. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.conditionalIf. Initiate a conditional sequence. The top value on the stack must be a boolean and will be popped. If it is true then the code following this call until the startElseCode() will be executed at runtime, otherwise the code following startElseCode() until the completeConditional() is called. See conditionalIfNull() for example and restrictions. Stack ...,boolean_value => ... .

conditionalIf

back to summary

public void conditionalIf()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.conditionalIf.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.conditionalIf.

Initiate a conditional sequence. The top value on the stack must be a boolean and will be popped. If it is true then the code following this call until the startElseCode() will be executed at runtime, otherwise the code following startElseCode() until the completeConditional() is called. See conditionalIfNull() for example and restrictions.

Stack ...,boolean_value =>
      ...

conditionalIf	back to summary
private void conditionalIf(short opcode)

conditionalIfNull	back to summary
public void conditionalIfNull() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.conditionalIfNull. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.conditionalIfNull. Initiate a conditional sequence. The top value on the stack (a reference) is popped and compared to 'null'. If the value is null then the code following this call until the startElseCode() will be executed at runtime, otherwise the code following startElseCode() until the completeConditional() is called. E.g. mb.callMethod(...); // pushes an object onto the stack mb.conditionalIfNull(); mb.push(3); mb.startElseCode(); mb.push(5); mb.completeConditional(); // at this point 3 or 5 will be on the stack Each path through the ?: statement must leave the stack at the same depth as the other. If the if or else code pops values from the stack that were before the conditional value, then they must use the same number of values from the stack. Stack ...,ref => ... .

conditionalIfNull

back to summary

public void conditionalIfNull()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.conditionalIfNull.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.conditionalIfNull.

Initiate a conditional sequence. The top value on the stack (a reference) is popped and compared to 'null'. If the value is null then the code following this call until the startElseCode() will be executed at runtime, otherwise the code following startElseCode() until the completeConditional() is called.
E.g.

mb.callMethod(...); // pushes an object onto the stack
mb.conditionalIfNull();
  mb.push(3);
mb.startElseCode();
  mb.push(5);
mb.completeConditional();
// at this point 3 or 5 will be on the stack

Each path through the ?: statement must leave the stack at the same depth as the other.
If the if or else code pops values from the stack that were before the conditional value, then they must use the same number of values from the stack.

Stack ...,ref =>
      ...

constantPool	back to summary
pack-priv ClassHolder constantPool() In their giveCode methods, the parts of the method body will want to get to the constant pool to add their constants. We really only want them treating it like a constant pool inclusion mechanism, we could write a wrapper to limit it to that.

copyStack	back to summary
private Type[] copyStack()

describeMethod	back to summary
public Object describeMethod(short opcode, String declaringClass, String methodName, String returnType) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.describeMethod. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.describeMethod. Return an object that efficiently (to the implementation) describes a zero-argument method and can be used with the single argument callMethod(). Descriptions for the parameters to this method are the same as the five argument callMethod(). This allows the caller to cache frequently used methods. The returned object is only valid for use by this MethodBuilder. This call does not affect the Stack.

describeMethod

back to summary

public Object describeMethod(short opcode, String declaringClass, String methodName, String returnType)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.describeMethod.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.describeMethod.

Return an object that efficiently (to the implementation) describes a zero-argument method and can be used with the single argument callMethod(). Descriptions for the parameters to this method are the same as the five argument callMethod(). This allows the caller to cache frequently used methods. The returned object is only valid for use by this MethodBuilder.
This call does not affect the Stack.

dup	back to summary
public void dup() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.dup. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.dup. Duplicate the top value on the stack. Stack ...,value => ...,value,value

dup

back to summary

public void dup()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.dup.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.dup.

Duplicate the top value on the stack.

Stack ...,value =>
      ...,value,value

endStatement	back to summary
public void endStatement() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.endStatement. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.endStatement. End a statement. Pops the top-word of the stack, if any. Must only be called if zero or one item exists on the stack. Stack value => :empty: or Stack :empty: => :empty: .

endStatement

back to summary

public void endStatement()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.endStatement.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.endStatement.

End a statement. Pops the top-word of the stack, if any. Must only be called if zero or one item exists on the stack.

Stack value =>
      :empty:
or

Stack :empty: =>
      :empty:

getArrayElement	back to summary
public void getArrayElement(int element) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getArrayElement. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.getArrayElement. Pop an array refrence off the stack and push an element from that array. Stack ...,array_ref => ...,value Parameters element:int Offset into the array (zero based)

getArrayElement

back to summary

public void getArrayElement(int element)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getArrayElement.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.getArrayElement.

Pop an array refrence off the stack and push an element from that array.

Stack ...,array_ref =>
      ...,value

Parameters

element:int: Offset into the array (zero based)

getField	back to summary
public void getField(LocalField field) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getField. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.getField. Push the contents of the local field onto the stack. This call pushes the this instance required to access the field itself. Stack ... => ...,field_value

getField

back to summary

public void getField(LocalField field)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getField.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.getField.

Push the contents of the local field onto the stack. This call pushes the this instance required to access the field itself.

Stack ...  =>
      ...,field_value

getField	back to summary
public void getField(String declaringClass, String fieldName, String fieldType) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getField. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.getField. Push the contents of the described field onto the stack. This call requires the instance (reference) to be pushed by the caller. Stack ...,field_ref => ...,field_value

getField

back to summary

public void getField(String declaringClass, String fieldName, String fieldType)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getField.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.getField.

Push the contents of the described field onto the stack. This call requires the instance (reference) to be pushed by the caller.

Stack ...,field_ref  =>
      ...,field_value

getField	back to summary
private void getField(short opcode, String declaringClass, String fieldName, String fieldType)

getName	back to summary
public String getName() Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getName. Return the logical name of the method. The current myEntry refers to the sub method we are currently overflowing to. Those sub-methods are hidden from any caller.

getName

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public String getName()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getName.

Return the logical name of the method. The current myEntry refers to the sub method we are currently overflowing to. Those sub-methods are hidden from any caller.

getNewSubMethod	back to summary
pack-priv final BCMethod getNewSubMethod(String returnType, boolean withParameters) Create a sub-method from this method to allow the code builder to split a single logical method into multiple methods to avoid the 64k per-method code size limit. The sub method with inherit the thrown exceptions of this method. Parameters returnType:String Return type of the new method withParameters:boolean True to define the method with matching parameters false to define it with no parameters. Returns:BCMethod A valid empty sub method.

getNewSubMethod

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pack-priv final BCMethod getNewSubMethod(String returnType, boolean withParameters)

Create a sub-method from this method to allow the code builder to split a single logical method into multiple methods to avoid the 64k per-method code size limit. The sub method with inherit the thrown exceptions of this method.

Parameters

returnType:String: Return type of the new method
withParameters:boolean: True to define the method with matching parameters false to define it with no parameters.

Returns:BCMethod

A valid empty sub method.

getParameter	back to summary
public void getParameter(int id) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getParameter. Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.getParameter. Push a parameter value. Stack ... => ...,param_value Parameters id:int position of the parameter (zero based).

getParameter

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public void getParameter(int id)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getParameter.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.getParameter.

Push a parameter value.

Stack ...  =>
      ...,param_value

Parameters

id:int: position of the parameter (zero based).

getStaticField	back to summary
public void getStaticField(String declaringClass, String fieldName, String fieldType) Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getStaticField. Push the contents of the described static field onto the stack.

getStaticField

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public void getStaticField(String declaringClass, String fieldName, String fieldType)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.getStaticField.

Push the contents of the described static field onto the stack.

growStack	back to summary
private void growStack(int size, Type type)

growStack	back to summary
private void growStack(Type type)

isInstanceOf

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public void isInstanceOf(String className)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.isInstanceOf.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.isInstanceOf.

Pop the top stack value and push a boolean that is the result of an instanceof check on the popped reference.

Stack ...,ref =>
      ...,boolean_value

methodReturn

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public void methodReturn()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.methodReturn.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.methodReturn.

Return from a method, optionally with a value. Must only be called if zero or one item exists on the stack. If the stack contains a single value then that is popped and used as the returned value.

Stack value =>
      :empty:
or

Stack :empty: =>
      :empty:

overflowMethodCheck back to summary

private void overflowMethodCheck()

Check to see if the current method byte code is nearing the limit of 65535. If it is start overflowing to a new method.

Overflow is handled for a method named e23 as: public Object e23() { ... existing code // split point return e23_0(); } private Object e23_0() { ... first set overflowed code // split point return e23_1(); } private Object e23_1() { ... second set overflowed code // method complete return result; }

These overflow methods are hidden from the code using this MethodBuilder, it continues to think that it is building a single method with the original name.
Restrictions:

Only handles methods with no arguments
Stack depth must be zero

pop

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public void pop()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pop.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.pop.

Pop the top value off the stack

Stack ..., value =>
      ...

popStack	back to summary
private Type popStack()

push

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public void push(byte value)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Push a byte constant onto the stack

Stack ...  =>
      ...,byte_value

push

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public void push(boolean value)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Push a boolean constant onto the stack

Stack ...  =>
      ...,boolean_value

push

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public void push(short value)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Push a short constant onto the stack

Stack ...  =>
      ...,short_value

push

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public void push(int value)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Push a int constant onto the stack

Stack ...  =>
      ...,int_value

push

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private void push(int value, Type type)

Push an integer value. Uses the special integer opcodes for the constants -1 to 5, BIPUSH for values that fit in a byte and SIPUSH for values that fit in a short. Otherwise uses LDC with a constant pool entry.

Parameters

value:int: Value to be pushed
type:Type: Final type of the value.

push

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public void push(long value)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Push a long value onto the stack. For the values zero and one the LCONST_0 and LCONST_1 instructions are used. For values betwee Short.MIN_VALUE and Short.MAX_VALUE inclusive an byte/short/int value is pushed using push(int, Type) followed by an I2L instruction. This saves using a constant pool entry for such values. All other values use a constant pool entry. For values in the range of an Integer an integer constant pool entry is created to allow sharing with integer constants and to reduce constant pool slot entries.

push

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public void push(float value)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Push a float constant onto the stack

Stack ...  =>
      ...,float_value

push

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public void push(double value)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Push a double constant onto the stack

Stack ...  =>
      ...,double_value

push

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public void push(String value)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.push.

Push a String constant onto the stack

Stack ...  =>
      ...,String_value

pushNewArray

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public void pushNewArray(String className, int size)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pushNewArray.

Create an array instance Stack ... => ...,arrayref

Parameters

className:String

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.pushNewArray.

- type of array.

size:int

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.pushNewArray.

- number of elements in the array

pushNewComplete

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public void pushNewComplete(int numArgs)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pushNewComplete.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.pushNewComplete.

Complete the sequence that was started with pushNewStart(). Pop the arguments to the constructor and push the reference to the newly created object.

Stack ...,value* => [numArgs number of values will be popped]
      ...,new_ref

Parameters

numArgs:int: number of arguments to the constructor (can be 0).

pushNewStart

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public void pushNewStart(String className)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pushNewStart.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.pushNewStart.

Initiate a sequence that calls a constructor, equivalent to the new operator in Java. After this call, the caller must push any arguments and then complete the construction with a call to pushNewComplete(). Only arguments to the constructor can be pushed onto the stack between the pushNewStart() and pushNewComplete() method calls.

Stack ... => [unchanged]
      ...

Parameters

className:String: class name of object to be created.

pushNull

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public void pushNull(String type)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pushNull.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.pushNull.

Push a typed null onto the stack

Stack ...  =>
      ...,null

pushThis

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public void pushThis()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.pushThis.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.pushThis.

Push this onto the stack.

Stack ...  =>
      ...,this_ref

putField

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public void putField(LocalField field)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.putField.

Upon entry the top word(s) on the stack is the value to be put into the field. Ie. we have

word

Before the call we need

word
this
word

word2,word1 -> word2, word1, word2 So that we are left with word after the put.

putField

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public void putField(String fieldName, String fieldType)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.putField.

Pop the top stack value and store it in the instance field of this class.

putField	back to summary
private void putField(Type fieldType, int cpi, boolean dup)

putField

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public void putField(String declaringClass, String fieldName, String fieldType)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.putField.

Pop the top stack value and store it in the field. This call requires the instance to be pushed by the caller.

setArrayElement

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public void setArrayElement(int element)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.setArrayElement.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.setArrayElement.

Pop an array reference off the stack, store a value in the array at the passed in offset.

Stack ...,array_ref, value =>
      ...

Parameters

element:int: Offset into the array (zero based)

setField

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public void setField(LocalField field)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.setField.

Set the field but don't duplicate its value so nothing is left on the stack after this call.

splitMethod

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private void splitMethod()

Attempt to split a large method by pushing code out to several sub-methods. Performs a number of steps.

Split at zero stack depth.
Split at non-zero stack depth (FUTURE)

If the class has already exceeded some limit in building the class file format structures then don't attempt to split. Most likely the number of constant pool entries has been exceeded and thus the built class file no longer has integrity. The split code relies on being able to read the in-memory version of the class file in order to determine descriptors for methods and fields.

startElseCode

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public void startElseCode()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.startElseCode.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.startElseCode.

Complete the true code path of a conditional.

statementNumHitLimit

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public boolean statementNumHitLimit(int noStatementsAdded)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.statementNumHitLimit.

Tell if statement number in this method builder hits limit. This method builder keeps a counter of how many statements are added to it. Caller should call this function every time it tries to add a statement to this method builder (counter is increased by 1), then the function returns whether the accumulated statement number hits a limit. The reason of doing this is that Java compiler has a limit of 64K code size for each method. We might hit this limit if an extremely long insert statement is issued, for example (see beetle 4293). Counting statement number is an approximation without too much overhead.

swap

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public void swap()

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.swap.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.swap.

Swap the top two values on the stack.

Stack ...,valueA,valueB =>
      ...,valueB,valueA

upCast

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public void upCast(String className)

Implements org.apache.derby.iapi.services.compiler.MethodBuilder.upCast.

Doc from org.apache.derby.iapi.services.compiler.MethodBuilder.upCast.

Upcast the top stack value. This is used for correct method resolution by upcasting method parameters. It does not put any casting code into the byte code stream. Can only be used for refrences.

Stack ...,ref =>
      ...,ref

vmNameDeclaringClass	back to summary
private Type vmNameDeclaringClass(String declaringClass)

writeExceptions	back to summary
protected void writeExceptions() sets exceptionBytes to the attribute_info needed for a method's Exceptions attribute. The ClassUtilities take care of the header 6 bytes for us, so they are not included here. See The Java Virtual Machine Specification Section 4.7.5, Exceptions attribute.

pack-priv Class BCMethod

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Field Detail

Constructor Detail

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