Transcript PPT - University of Delaware

JikesRVM
Dept of Computer & Information Sciences
University of Delaware
CISC 673 : Optimizing Compilers
Contents
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Introduction to JikesRVM
Optimizations
IRs (Intermediate Representations)
Editing JikesRVM
Steps For Project1
Questions
CISC 673 : Optimizing Compilers
Introduction to JikesRVM
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This is not a Java source compiler.
JikesRVM is a Virtual Machine.
Open Source.
Converts from Byte code  Machine Code
CISC 673 : Optimizing Compilers
Functions of the RVM
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Loads the required class files
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Converts the class files (OS independent bytecode)
to machine code (OS and Architecture dependent)
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Optimizes byte code in the process of the above
conversion.
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Tracks Compilation time and provides rudimentary
profiling.
CISC 673 : Optimizing Compilers
Compilation
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Download the gz file from source forge
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http://downloads.sourceforge.net/jikesrvm/jikesrvm3.0.1.tar.bz2
by using the command wget <web link>
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Untar the file “tar –zxf jikesrvm-3.0.1.tar.bz2”
Inside the jikesrvm directory create a new
.ant.properties file
http://www.cis.udel.edu/~skulkarn/ta_files/.ant.properties
CISC 673 : Optimizing Compilers
Compilation II
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Run command “java-config -s sun-jdk-1.6”
Inside this directory run “ant” and this would create
the executable image of the rvm.
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Binaries are stored in (jikesrvm3.0.1/dist/FastAdaptiveGenMS_x86_64-linux) folder
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Compile your source code with javac
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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
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There are different levels of optimizations from O0
to O3.
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List of optimizations that are performed in all the
different optimization levels are available at
http://www.cis.udel.edu/~skulkarn/ta_files/OptLevels.tar.gz
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In brief no of steps in various
optimization levels are:
Each level of optimization
is a super set of the previous
level.
O0
O1
44
53
O2
53
CISC 673 : Optimizing Compilers
Intermediate
Representations
For more information please go thru
http://www.ugrad.cs.ubc.ca/~cs411/2006W2/handouts/jikes-IR-shanebrewer.pdf
CISC 673 : Optimizing Compilers
Editing the JikesRVM
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Adding of a new command line argument
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The list of files that govern and define the parameters are at “jikesrvm3.0.0/rvm/src-generated/options”
I wanted to add a parameter that could switch off multiple optimizations
at the same time, so I added
“V LIST_TO_SKIP String \"123\“
List of optimizations to skip”
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
Important source directories
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Package responsible for choosing the optimizations is
org.jikesrvm.compilers.opt.driver
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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
Steps for Project1
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Step1 and Step 2 are straightfwd.
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Step3: use “time rvm <command line parameters>”
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Step4: Based on the different optimizations that you
would like to switch off, find and compare the
results of running time.
E.g. You might want to switch off “Local
ConstantProp” or “Branch Optimizations” and see
the effect it has on the running times.
CISC 673 : Optimizing Compilers
Questions?
Most of the files and this presentation is available at
http://www.cis.udel.edu/~skulkarn/ta.html
CISC 673 : Optimizing Compilers