Package daikon.dcomp

Class Premain

Object

Premain

public class Premain
extends Object

This class is the entry point for the DynComp instrumentation agent. It is the only code in dcomp_premain.jar.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Premain.ShutdownThread	Shutdown thread that writes out the comparability results.

Field Summary

Fields

Modifier and Type	Field	Description
static boolean	debug_dcinstrument	Turn on basic DCInstrument debugging options.
static boolean	debug_dcruntime	Turn on basic DCRuntime debugging options.
static boolean	debug_dcruntime_all	Turn on most DCRuntime debugging options.
protected static boolean	in_shutdown	One of the last phases for DynComp is to write out the comparability values after the user program completes execution.
protected static Set<String>	pre_instrumented	Set of pre-instrumented JDK classes.
protected static Set<String>	problem_classes	Set of classes known to cause problems when instrumented.
protected static Set<String>	problem_methods	Set of methods known to cause problems when instrumented.
protected static Set<String>	problem_packages	Set of packages known to cause problems when instrumented.
static boolean	verbose	If true, print information about the classes being transformed.

Constructor Summary

Constructors

Constructor	Description
Premain()

Method Summary

Modifier and Type	Method	Description
static PrintWriter	open(File filename)	Helper method to create a PrintWriter from a File.
static void	premain(String agentArgs, Instrumentation inst)	This method is the entry point of the Java agent.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

debug_dcinstrument

public static boolean debug_dcinstrument

Turn on basic DCInstrument debugging options.

debug_dcruntime

public static boolean debug_dcruntime

Turn on basic DCRuntime debugging options.

debug_dcruntime_all

public static boolean debug_dcruntime_all

Turn on most DCRuntime debugging options.

verbose

public static boolean verbose

If true, print information about the classes being transformed.

pre_instrumented

protected static Set<String> pre_instrumented

Set of pre-instrumented JDK classes.

problem_packages

protected static Set<String> problem_packages

Set of packages known to cause problems when instrumented.

problem_classes

protected static Set<String> problem_classes

Set of classes known to cause problems when instrumented.

problem_methods

protected static Set<String> problem_methods

Set of methods known to cause problems when instrumented.

in_shutdown

protected static boolean in_shutdown

One of the last phases for DynComp is to write out the comparability values after the user program completes execution. One of the steps is to assign values to the arguments of methods that have not been executed. We use reflection to get type information about these arguments, which causes the method to be loaded; which causes the main part of DynComp to try to instrument the method. As the user program has completed execution, doing instrumentation at this point can lead to problems. The correct fix for this problem is to use BCEL to get the type information instead of reflection, thus avoiding loading the method into the JVM. This will be a large change, so a temporary fix is to indicate if the program is in shutdown mode and not instrument any methods when this flag is true. TODO: Couldn't we just call removeTransformer at the start of shutdown?

Constructor Detail

Premain

public Premain()

Method Detail

premain

public static void premain(String agentArgs,
                           Instrumentation inst)
                    throws IOException

This method is the entry point of the Java agent. Its main purpose is to set up the transformer so that when classes from the target app are loaded, they are first transformed in order to add comparability instrumentation.

Parameters:

agentArgs - string containing the arguments passed to this agent

inst - instrumentation instance to be used to transform classes

Throws:

IOException - if jdk_classes.txt cannot be read or if the correct version of BCEL cannot be found or loaded

open

public static PrintWriter open(File filename)

Helper method to create a PrintWriter from a File.

Parameters:

filename - the File to be opened

Returns:

a new PrintWriter from filename