HotSpotConstantReflectionProvider (Graal OpenJDK Project Documentation)

java.lang.Object
- jdk.internal.jvmci.hotspot.HotSpotConstantReflectionProvider

All Implemented Interfaces:

HotSpotProxified, ConstantReflectionProvider

Direct Known Subclasses:

HotSpotGraalConstantReflectionProvider
```
public class HotSpotConstantReflectionProvider
extends Object
implements ConstantReflectionProvider, HotSpotProxified
```
HotSpot implementation of ConstantReflectionProvider.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

(package private) static class HotSpotConstantReflectionProvider.Options

Nested Classes
Modifier and Type	Class and Description
`(package private) static class`	`HotSpotConstantReflectionProvider.Options`

Field Summary

Fields
Modifier and Type	Field and Description
`protected HotSpotMemoryAccessProviderImpl`	`memoryAccess`
`protected HotSpotMethodHandleAccessProvider`	`methodHandleAccess`
`protected HotSpotJVMCIRuntimeProvider`	`runtime`
`private static String`	`SystemClassName`

Constructor Summary

Constructors
Constructor and Description

HotSpotConstantReflectionProvider(HotSpotJVMCIRuntimeProvider runtime)

Constructors
Constructor and Description
`HotSpotConstantReflectionProvider(HotSpotJVMCIRuntimeProvider runtime)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`ResolvedJavaType`	`asJavaType(Constant constant)` Returns the `ResolvedJavaType` for a `Class` object (or any other object regarded as a class by the VM) encapsulated in the given constant.
`JavaConstant`	`boxPrimitive(JavaConstant source)` Converts the given `primitive` constant to a boxed `object` constant, according to the Java boxing rules.
`Boolean`	`constantEquals(Constant x, Constant y)` Compares two constants for equality.
`JavaConstant`	`forString(String value)` Gets a string as a `JavaConstant`.
`private static int`	`getArrayDimension(JavaType type)`
`MemoryAccessProvider`	`getMemoryAccessProvider()` Gets raw memory access.
`MethodHandleAccessProvider`	`getMethodHandleAccess()` Gets access to the internals of `MethodHandle`.
`private int`	`indexForOffset(JavaConstant array, long offset)` Try to convert `offset` into an an index into `array`.
`private static boolean`	`isBoxCached(JavaConstant source)` Check if the constant is a boxed value that is guaranteed to be cached by the platform.
`protected boolean`	`isFinalInstanceFieldValueConstant(JavaConstant value, Class<?> receiverClass)` Determines if a value read from a `final` instance field is considered constant.
`protected boolean`	`isStableInstanceFieldValueConstant(JavaConstant value, Class<?> receiverClass)` Determines if a value read from a `Stable` instance field is considered constant.
`protected boolean`	`isStaticFieldConstant(HotSpotResolvedJavaField staticField)` Determines if a static field is constant for the purpose of `readConstantFieldValue(JavaField, JavaConstant)`.
`JavaConstant`	`readArrayElement(JavaConstant array, int index)` Reads a value from the given array at the given index.
`Integer`	`readArrayLength(JavaConstant array)` Returns the length of the array constant.
`JavaConstant`	`readConstantArrayElement(JavaConstant array, int index)` Reads a value from the given array at the given index if it is a stable array.
`JavaConstant`	`readConstantArrayElementForOffset(JavaConstant array, long offset)` Reads a value from the given array at the given offset if it is a stable array.
`JavaConstant`	`readConstantFieldValue(JavaField field, JavaConstant receiver)` Gets the constant value of this field.
`JavaConstant`	`readFieldValue(JavaField field, JavaConstant receiver)` Gets the current value of this field for a given object, if available.
`private JavaConstant`	`readNonStableFieldValue(JavaField field, JavaConstant receiver)`
`JavaConstant`	`readStableFieldValue(JavaField field, JavaConstant receiver, boolean isDefaultStable)` Gets the current value of this field for a given object, if available.
`JavaConstant`	`unboxPrimitive(JavaConstant source)` Converts the given `object` constant to a `primitive` constant, according to the Java unboxing rules.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - runtime
```
protected final HotSpotJVMCIRuntimeProvider runtime
```
  - methodHandleAccess
```
protected final HotSpotMethodHandleAccessProvider methodHandleAccess
```
  - memoryAccess
```
protected final HotSpotMemoryAccessProviderImpl memoryAccess
```
  - SystemClassName
```
private static final String SystemClassName
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - HotSpotConstantReflectionProvider
```
public HotSpotConstantReflectionProvider(HotSpotJVMCIRuntimeProvider runtime)
```
- Method Detail
  - getMethodHandleAccess
```
public MethodHandleAccessProvider getMethodHandleAccess()
```
    Description copied from interface: ConstantReflectionProvider
    
    Gets access to the internals of MethodHandle.
    
    Specified by:
    
    getMethodHandleAccess in interface ConstantReflectionProvider
  - getMemoryAccessProvider
```
public MemoryAccessProvider getMemoryAccessProvider()
```
    Description copied from interface: ConstantReflectionProvider
    
    Gets raw memory access.
    
    Specified by:
    
    getMemoryAccessProvider in interface ConstantReflectionProvider
  - constantEquals
```
public Boolean constantEquals(Constant x,
                              Constant y)
```
    Description copied from interface: ConstantReflectionProvider
    
    Compares two constants for equality. The equality relationship is symmetric. Returns true if the two constants represent the same run time value, false if they are different. Returns null if the constants cannot be compared at this point.
    
    Specified by:
    
    constantEquals in interface ConstantReflectionProvider
  - readArrayLength
```
public Integer readArrayLength(JavaConstant array)
```
    Description copied from interface: ConstantReflectionProvider
    
    Returns the length of the array constant. Returns null if the constant is not an array, or if the array length is not available at this point.
    
    Specified by:
    
    readArrayLength in interface ConstantReflectionProvider
  - readConstantArrayElement
```
public JavaConstant readConstantArrayElement(JavaConstant array,
                                             int index)
```
    Description copied from interface: ConstantReflectionProvider
    
    Reads a value from the given array at the given index if it is a stable array. Returns null if the constant is not a stable array, if it is a default value, if the index is out of bounds, or if the value is not available at this point.
    
    Specified by:
    
    readConstantArrayElement in interface ConstantReflectionProvider
  - indexForOffset
```
private int indexForOffset(JavaConstant array,
                           long offset)
```
    Try to convert offset into an an index into array.
    
    Returns:
    
    the computed index or -1 if the offset isn't within the array
  - readConstantArrayElementForOffset
```
public JavaConstant readConstantArrayElementForOffset(JavaConstant array,
                                                      long offset)
```
    Description copied from interface: ConstantReflectionProvider
    
    Reads a value from the given array at the given offset if it is a stable array. The offset will be decoded relative to the platform addressing into an index into the array. Returns null if the constant is not a stable array, if it is a default value, if the offset is out of bounds, or if the value is not available at this point.
    
    Specified by:
    
    readConstantArrayElementForOffset in interface ConstantReflectionProvider
  - readArrayElement
```
public JavaConstant readArrayElement(JavaConstant array,
                                     int index)
```
    Description copied from interface: ConstantReflectionProvider
    
    Reads a value from the given array at the given index. Returns null if the constant is not an array, if the index is out of bounds, or if the value is not available at this point.
    
    Specified by:
    
    readArrayElement in interface ConstantReflectionProvider
  - isBoxCached
```
private static boolean isBoxCached(JavaConstant source)
```
    Check if the constant is a boxed value that is guaranteed to be cached by the platform. Otherwise the generated code might be the only reference to the boxed value and since object references from nmethods are weak this can cause GC problems.
    
    Parameters:
    
    source -
    
    Returns:
    
    true if the box is cached
  - boxPrimitive
```
public JavaConstant boxPrimitive(JavaConstant source)
```
    Description copied from interface: ConstantReflectionProvider
    
    Converts the given primitive constant to a boxed object constant, according to the Java boxing rules. Returns null if the source is is not a primitive constant, or the boxed value is not available at this point.
    
    Specified by:
    
    boxPrimitive in interface ConstantReflectionProvider
  - unboxPrimitive
```
public JavaConstant unboxPrimitive(JavaConstant source)
```
    Description copied from interface: ConstantReflectionProvider
    
    Converts the given object constant to a primitive constant, according to the Java unboxing rules. Returns null if the source is is not an object constant that can be unboxed, or the unboxed value is not available at this point.
    
    Specified by:
    
    unboxPrimitive in interface ConstantReflectionProvider
  - forString
```
public JavaConstant forString(String value)
```
    Description copied from interface: ConstantReflectionProvider
    
    Gets a string as a JavaConstant.
    
    Specified by:
    
    forString in interface ConstantReflectionProvider
  - asJavaType
```
public ResolvedJavaType asJavaType(Constant constant)
```
    Description copied from interface: ConstantReflectionProvider
    
    Returns the ResolvedJavaType for a Class object (or any other object regarded as a class by the VM) encapsulated in the given constant. Returns null if the constant does not encapsulate a class, or if the type is not available at this point.
    
    Specified by:
    
    asJavaType in interface ConstantReflectionProvider
  - isStaticFieldConstant
```
protected boolean isStaticFieldConstant(HotSpotResolvedJavaField staticField)
```
    Determines if a static field is constant for the purpose of readConstantFieldValue(JavaField, JavaConstant).
  - isFinalInstanceFieldValueConstant
```
protected boolean isFinalInstanceFieldValueConstant(JavaConstant value,
                                                    Class<?> receiverClass)
```
    Determines if a value read from a final instance field is considered constant. The implementation in HotSpotConstantReflectionProvider returns true if value is not the default value for its kind or if HotSpotConstantReflectionProvider.Options.TrustFinalDefaultFields is true.
    
    Parameters:
    
    value - a value read from a final instance field
    
    receiverClass - the class of object from which the value was read
  - isStableInstanceFieldValueConstant
```
protected boolean isStableInstanceFieldValueConstant(JavaConstant value,
                                                     Class<?> receiverClass)
```
    Determines if a value read from a Stable instance field is considered constant. The implementation in HotSpotConstantReflectionProvider returns true if value is not the default value for its kind.
    
    Parameters:
    
    value - a value read from a Stable field
    
    receiverClass - the class of object from which the value was read
  - readConstantFieldValue
```
public JavaConstant readConstantFieldValue(JavaField field,
                                           JavaConstant receiver)
```
    Gets the constant value of this field. Note that a static final field may not be considered constant if its declaring class is not yet initialized or if it is a well known field that can be updated via other means (e.g., System.setOut(java.io.PrintStream)).
    The value field in OptionValue is considered constant if the type of receiver is (assignable to) StableOptionValue.
    
    Specified by:
    
    readConstantFieldValue in interface ConstantReflectionProvider
    
    receiver - object from which this field's value is to be read. This value is ignored if this field is static.
    
    Returns:
    
    the constant value of this field or null if this field is not considered constant by the runtime
  - readFieldValue
```
public JavaConstant readFieldValue(JavaField field,
                                   JavaConstant receiver)
```
    Description copied from interface: ConstantReflectionProvider
    
    Gets the current value of this field for a given object, if available. There is no guarantee that the same value will be returned by this method for a field unless the field is considered to be constant by the runtime.
    
    Specified by:
    
    readFieldValue in interface ConstantReflectionProvider
    
    receiver - object from which this field's value is to be read. This value is ignored if this field is static.
    
    Returns:
    
    the value of this field or null if the value is not available (e.g., because the field holder is not yet initialized).
  - readNonStableFieldValue
```
private JavaConstant readNonStableFieldValue(JavaField field,
                                             JavaConstant receiver)
```
  - readStableFieldValue
```
public JavaConstant readStableFieldValue(JavaField field,
                                         JavaConstant receiver,
                                         boolean isDefaultStable)
```
    Description copied from interface: ConstantReflectionProvider
    
    Gets the current value of this field for a given object, if available. Like ConstantReflectionProvider.readFieldValue(JavaField, JavaConstant) but treats array fields as stable. There is no guarantee that the same value will be returned by this method for a field unless the field is considered to be constant by the runtime.
    
    Specified by:
    
    readStableFieldValue in interface ConstantReflectionProvider
    
    receiver - object from which this field's value is to be read. This value is ignored if this field is static.
    
    isDefaultStable - if true, default values are considered stable
    
    Returns:
    
    the value of this field or null if the value is not available (e.g., because the field holder is not yet initialized).
  - getArrayDimension
```
private static int getArrayDimension(JavaType type)
```

Class HotSpotConstantReflectionProvider

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

runtime

methodHandleAccess

memoryAccess

SystemClassName

Constructor Detail

HotSpotConstantReflectionProvider

Method Detail

getMethodHandleAccess

getMemoryAccessProvider

constantEquals

readArrayLength

readConstantArrayElement

indexForOffset

readConstantArrayElementForOffset

readArrayElement

isBoxCached

boxPrimitive

unboxPrimitive

forString

asJavaType

isStaticFieldConstant

isFinalInstanceFieldValueConstant

isStableInstanceFieldValueConstant

readConstantFieldValue

readFieldValue

readNonStableFieldValue

readStableFieldValue

getArrayDimension