APIdia Launch Partner
Top Description Constructors Methods
jdk.jfr.internal

pack-priv final Class JVMUpcalls

extends Object
Class Inheritance
Imports
java.lang.reflect.Modifier, jdk.jfr.internal.event.EventConfiguration, jdk.jfr.internal.util.Bytecode, .Utils, jdk.jfr.internal.tracing.PlatformTracer
All upcalls from the JVM should go through this class.

Constructor Summary

AccessConstructor and Description
pack-priv
JVMUpcalls()

Method Summary

Modifier and TypeMethod and Description
pack-priv static byte[]

Returns:

byte code to use
bytesForEagerInstrumentation(long
Id of the class
traceId, boolean
add instrumentation regardless if event is enabled or not.
forceInstrumentation, boolean bootClassLoader, Class<?>
the super class of the class being processed
superClass, byte[]
byte code
oldBytes)

Called by the JVM when requested to do an "eager" instrumentation.

pack-priv static Thread

Returns:

a new thread
createRecorderThread(ThreadGroup
the system thread group
systemThreadGroup, ClassLoader
the context class loader.
contextClassLoader)

Called by the JVM to create the recorder thread.

public static byte[]

Returns:

the instrumented bytecode, or null if the class can't or shouldn't be modified.
onMethodTrace(Module
the module the class belongs to
module, ClassLoader
the class loader the class is being loaded for
classLoader, String
the internal class name, i.e. java/lang/String.
className, byte[]
the bytecode to modify
bytecode, long[]
the method IDs
methodIds, String[]
constant pool indices of method names
names, String[]
constant pool indices of method signatures
signatures, int[]
integer mask describing the modification
modifications)

Called by the JVM to update method tracing instrumentation.

pack-priv static byte[]

Returns:

byte code to use
onRetransform(long
Id of the class
traceId, boolean
not used, but act as padding so bytesForEagerInstrumentation and onRetransform can have identical method signatures, which simplifies the invoke machinery in native
dummy1, boolean
not used, but act as padding so bytesForEagerInstrumentation and onRetransform can have identical method signatures, which simplifies the invoke machinery in native
dummy2, Class<?>
class being retransformed
clazz, byte[]
byte code
oldBytes)

Called by the JVM when a retransform happens on a tagged class

public static void
publishMethodTimersForClass(long
the methods to be published
classId)

Called by the JVM to publish a class ID that can safely be used by the Method Timing event.

pack-priv static void
unhideInternalTypes()

Called by the JVM to ensure metadata for internal events/types become public.

Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Constructor Detail

JVMUpcallsback to summary
pack-priv JVMUpcalls()

Method Detail

bytesForEagerInstrumentationback to summary
pack-priv static byte[] bytesForEagerInstrumentation(long traceId, boolean forceInstrumentation, boolean bootClassLoader, Class<?> superClass, byte[] oldBytes) throws Throwable

Called by the JVM when requested to do an "eager" instrumentation. Would normally happen when JVMTI retransform capabilities are not available.

Parameters
traceId:long

Id of the class

forceInstrumentation:boolean

add instrumentation regardless if event is enabled or not.

superClass:Class<?>

the super class of the class being processed

oldBytes:byte[]

byte code

Returns:byte[]

byte code to use

createRecorderThreadback to summary
pack-priv static Thread createRecorderThread(ThreadGroup systemThreadGroup, ClassLoader contextClassLoader)

Called by the JVM to create the recorder thread.

Parameters
systemThreadGroup:ThreadGroup

the system thread group

contextClassLoader:ClassLoader

the context class loader.

Returns:Thread

a new thread

onMethodTraceback to summary
public static byte[] onMethodTrace(Module module, ClassLoader classLoader, String className, byte[] bytecode, long[] methodIds, String[] names, String[] signatures, int[] modifications)

Called by the JVM to update method tracing instrumentation.

Parameters
module:Module

the module the class belongs to

classLoader:ClassLoader

the class loader the class is being loaded for

className:String

the internal class name, i.e. java/lang/String.

bytecode:byte[]

the bytecode to modify

methodIds:long[]

the method IDs

names:String[]

constant pool indices of method names

signatures:String[]

constant pool indices of method signatures

modifications:int[]

integer mask describing the modification

Returns:byte[]

the instrumented bytecode, or null if the class can't or shouldn't be modified.

onRetransformback to summary
pack-priv static byte[] onRetransform(long traceId, boolean dummy1, boolean dummy2, Class<?> clazz, byte[] oldBytes) throws Throwable

Called by the JVM when a retransform happens on a tagged class

Parameters
traceId:long

Id of the class

dummy1:boolean

not used, but act as padding so bytesForEagerInstrumentation and onRetransform can have identical method signatures, which simplifies the invoke machinery in native

dummy2:boolean

not used, but act as padding so bytesForEagerInstrumentation and onRetransform can have identical method signatures, which simplifies the invoke machinery in native

clazz:Class<?>

class being retransformed

oldBytes:byte[]

byte code

Returns:byte[]

byte code to use

publishMethodTimersForClassback to summary
public static void publishMethodTimersForClass(long classId)

Called by the JVM to publish a class ID that can safely be used by the Method Timing event.

Parameters
classId:long

the methods to be published

unhideInternalTypesback to summary
pack-priv static void unhideInternalTypes()

Called by the JVM to ensure metadata for internal events/types become public. Must be called after metadata repository has been initialized (JFR created).