CStarOptimizing a C Compiler

Group Hellim

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GROUP MEMBERS

- Halit Emre Sayılır

- Anıl Koyuncu

- Kutay Yıldırıcı

- Tayfun Çakıcıer

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OUTLINE

• Problem Definition

• Framework Information

• Modules

1 Optimizations

2 Optimization Manager

3 Test Case Generator

• Screenshots

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Why• Performance and Efficiency

- Reduce Execution Time- Decrease Space of Code- Reduce Memory Space

• Must be Reliable

PROBLEM DEFINITION

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FRAMEWORK INFO

• Object Oriented Software Library

• Own intermediate representation

• Design by Contract

• Modular

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OPTIMIZATIONSDead Code Elemination

if(0)

a=1;

else will be replaced bya=2; a=2;

Evaluation of if statement in run time avoided

Space of code reduced

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OPTIMIZATIONS(cont.)

Constant Folding

return 100*40 return 4000

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Local Copy Propagation

a=b;

c=a+d;

OPTIMIZATIONS(cont.)

c = b + d ;

also after dead code elimination

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OPTIMIZATIONS(%35)

- Constant Folding (+)

- Basic Block Ordering

- Dead Code Elimination

- Local/Global Forward Substitution

- Local/Global Copy Propagation(+)

- Strength Reduction (+)

- Local/Global Common SubExpression Elimination (+)

- If Simplifications

- Algebraic Simplifications (+)

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OPTIMIZATIONS(cont.)

• Dead Object Elimination

• Jump Optimizations

• Tail Merging

• Tail Recursion

• Procedure Cloning and Specilization

• Partial Redundancy Elimination

• Unreachable Code Elimination (+)

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OPTIMIZATION MANAGER(%40)

• A tool for managing the optimizations which will be used during compilation

• An assistant for advanced users

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• Two modes:

1- File mode: There is an external file. The optimizations

which will be used ,are configured in the file When the file is read , rules will be managed

and then chosen optimizations will be executed

OPTIMIZATION MANAGER

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Optimization Manager Configuration File

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2- Interactive mode: It is a mode which interacts with user. The user will enter input via keyboard. Optimizations will be done in an interactive

manner.

OPTIMIZATION MANAGER

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TEST CASE GENERATOR(%30)

Aim:

Automating the process of test case generation

* Reduce and prevent human errors

* Flexibility for generation of different test cases

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How

TEST CASE GENERATOR

Option File Inspection

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OPTION FILE

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How

TEST CASE GENERATOR

Option File Inspection

Parse OptionFile

Generate Options

IR CodeGeneration

IR DumpGenerated Test File

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Screenshots

• Some result screenshots of the optimizations

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Constant Folding

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Algebraic Simplifications

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Local Common Subexpression Elimination

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QUESTIONS

? ? ?