Four Projects Simplifying Comparing Locating Input Coverage - - PDF document

Andreas Zeller

About the Course

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Course Topics

• Tracking and Reproducing Problems
• The Scientific Method
• Making Programs Fail
• Isolating Failure Causes (automatically)
• Locating and Fixing Defects

“Why does my Program Fail?”

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Your Lecturer

Andreas Zeller

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Your Tutor

Andrzej Wasylkowski

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Course Material

• Book “Why programs fail”

http://www.whyprogramsfail.com/

• Lecture slides, dates, links…

http://www.st.cs.uni-sb.de/edu/ adebug/2008/

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Course Format

• 15 lectures
• Four projects (“write your own debugger”)
• Oral exams at end of semester

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Four Projects

Simplifying Input

3 weeks

Comparing Coverage

3 weeks

Locating Causes

4 weeks

(plus 1 more) written in Python for Python

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<SELECT NAME="op_sys" MULTIPLE SIZE=7> <OPTION VALUE="All">All<OPTION VALUE="Windows 3.1">Windows 3.1<OPTION VALUE="Windows 95">Windows 95<OPTION VALUE="Windows 98">Windows 98<OPTION VALUE="Windows ME">Windows ME<OPTION VALUE="Windows 2000">Windows 2000<OPTION VALUE="Windows NT">Windows NT<OPTION VALUE="Mac System 7">Mac System 7<OPTION VALUE="Mac System 7.5">Mac System 7.5<OPTION VALUE="Mac System 7.6.1">Mac System 7.6.1<OPTION VALUE="Mac System 8.0">Mac System 8.0<OPTION VALUE="Mac System 8.5">Mac System 8.5<OPTION VALUE="Mac System 8.6">Mac System 8.6<OPTION VALUE="Mac System 9.x">Mac System 9.x<OPTION VALUE="MacOS X">MacOS X<OPTION VALUE="Linux">Linux<OPTION VALUE="BSDI">BSDI<OPTION VALUE="FreeBSD">FreeBSD<OPTION VALUE="NetBSD">NetBSD<OPTION VALUE="OpenBSD">OpenBSD<OPTION VALUE="AIX">AIX<OPTION VALUE="BeOS">BeOS<OPTION VALUE="HP-UX">HP-UX<OPTION VALUE="IRIX">IRIX<OPTION VALUE="Neutrino">Neutrino<OPTION VALUE="OpenVMS">OpenVMS<OPTION VALUE="OS/2">OS/2<OPTION VALUE="OSF/ 1">OSF/1<OPTION VALUE="Solaris">Solaris<OPTION VALUE="SunOS">SunOS<OPTION VALUE="other">other</SELECT> </td> <td align=left valign=top> <SELECT NAME="priority" MULTIPLE SIZE=7> <OPTION VALUE="--">--<OPTION VALUE="P1">P1<OPTION VALUE="P2">P2<OPTION VALUE="P3">P3<OPTION VALUE="P4">P4<OPTION VALUE="P5">P5</SELECT>

Simplifying Input

What’s relevant in here?

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Comparing Coverage

sample 9 8 7 $ Output: 7 8 9 sample 11 14 $ Output: 0 11 How do these runs differ?

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if (GET_CODE (XEXP (x, 0)) == PLUS { x = apply_distributive_law (gen_binary (PLUS, mode, gen_binary (MULT, mode, XEXP (XEXP (x, 0), 0), XEXP (x, 1)), gen_binary (MULT, mode, XEXP (XEXP (x, 0), 1), XEXP (x, 1)))); if (GET_CODE (x) != MULT) return x; }

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Locating Causes

What causes the failure?

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Grading

50% 15% 15% 10% 10%

Project 1 Project 2 Project 3 Project 4 Oral Exam

Assessment

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10 11 12

Exam

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About the Course

Tracking Problems

Making Programs Fail

Simplifying Problems

The Scientific Method

Deducing Errors

Reproducing Problems

Observing Facts

Tracking Origins

Asserting Expectations

System Assertions

Comparing Coverage

Causes and Eects

Isolating Failure Causes

Isolating Cause-EectChains

Locating Failure Causes

How Failures Come to be

Detecting Anomalies

Fixing the Defect

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