CISC 673 : Optimizing Compilers Dept of Computer & Information Sciences University of Delaware JikesRVM

CISC 673 : Optimizing Compilers Contents Introduction to JikesRVM Optimizations IRs (Intermediate Representations) Modifying the JikesRVM Steps For Project1 Questions

CISC 673 : Optimizing Compilers Introduction to JikesRVM This is not a Java source compiler. JikesRVM is a Virtual Machine. Converts from Byte code  Machine Code

CISC 673 : Optimizing Compilers Introduction to JikesRVM Functions of the RVM Loads class files when needed Converts the class files (OS independent bytecode) to machine code (OS and Architecture dependent) Optimizes byte code in the process of the above conversion. Tracks Compilation time and provides rudimentary profiling.

CISC 673 : Optimizing Compilers Compiling Jikes Download the gz file from source forge tar.gz?use_mirror=superb-west by using the command wget tar.gz?use_mirror=superb-west Untar the file “tar –zxf jikesrvm tar.bz2” Inside the jikesrvm directory create a new.ant.properties file ( ) Run command “java-config -s sun-jdk-1.6” Inside this directory run “ant” and this would create the executable image of the rvm. Binaries are stored in (jikesrvm-3.0.1/dist/FastAdaptiveGenMS_x86_64-linux) folder Compile your source code with the javac command and run using the “rvm” binary present in the above folder. You may want to add this directory to the PATH environment variable.

CISC 673 : Optimizing Compilers Optimization No of steps O044 O153 O253 O367 Levels of Optimization: O0 to O3. List of optimizations ( ) Number of steps in an optimization level:

CISC 673 : Optimizing Compilers Intermediate Representations

CISC 673 : Optimizing Compilers Important source directories Package responsible for choosing the optimizations is org.jikesrvm.compilers.opt.driver OptimizationPlanner.java: is responsible for creating the list of optimizations that the code would go through. CompilationPlan.java: Performs those optimizations in the order that was set in OptimizationPlanner. Actuall implementations of the optimizations can be found under the root package org.jikesrvm.compilers.opt e.g. LocalCastOptimization.java is the implementation LocalCastOptimization.

CISC 673 : Optimizing Compilers Modifying the JikesRVM Adding of a new command line argument Directory “jikesrvm-3.0.0/rvm/src-generated/options” Change ValueOptions.opt.dat or BooleanOptions.opt.dat Remember that the number of new lines also are important. So do not upset those. You will have to clean the previous build by using “ant very-clean” command Build again by “ant” command.

CISC 673 : Optimizing Compilers Steps for Project1 Based on the steps provided on the class website: Step1: Writing a Java Code. Step2: Screenshot of running the RVM. Step3: use “time rvm ” to count the time taken. Step4: Turn off optimizations and compare the resulting running time.

CISC 673 : Optimizing Compilers Questions? Most of the files and this presentation is available at