add more content in contr

TSW/backg.tex

@@ -14,8 +14,8 @@ UBs: division by zero, oversized shift, signed integer overflow,
 out-of-bounds pointer, null pointer dereference, type-punned pointer
 dereference and uninitialized read. The consequences of these
 optimizations range from unexpected code
-generation~\cite{chen_2014,fermat_ub} to real-life
-vulnerabilities~\cite{mitre_ub}.
+generation~\cite{chen2014,fermatub} to real-life
+vulnerabilities~\cite{mitreub}.
 
 To address these issues the research community created solutions that
 tackle the problem from different angles.  One approach was to introduce

TSW/bib.bib

@@ -7,7 +7,7 @@ and Zeldovich, Nickolai and Kaashoek, M Frans},
   year={2012}
 }
 
-@misc{checks_2008,
+@misc{checks2008,
   title={CERT/CC Vulnerability note vu162289},
   url={https://www.kb.cert.org/vuls/id/162289/},
   journal={VU162289 - C compilers may silently discard some wraparound
@@ -35,7 +35,7 @@ Systems Principles},
   year={2003}
 }
 
-@misc{google_2015, title={BORINGCC},
+@misc{google2015, title={BORINGCC},
 url={https://groups.google.com/g/boring-crypto/c/48qa1kWignU/m/o8GGp2K1DAAJ},
 journal={Google}, publisher={Google}, year={2015}, month={Dec}} 
 
@@ -48,7 +48,7 @@ Programmierung (KPS 2015)},
   year={2015}
 }
 
-@misc{regehr_2014,
+@misc{regehr2014,
   title={Proposal for a Friendly Dialect of C},
   url={https://blog.regehr.org/archives/1180},
   journal={Embedded in Academia},
@@ -57,7 +57,7 @@ Programmierung (KPS 2015)},
   month={Aug}
 } 
 
-@misc{chen_2014,
+@misc{chen2014,
   title={Undefined behavior can result in time travel},
   url={https://devblogs.microsoft.com/oldnewthing/20140627-00/?p=633},
   journal={The Old New Thing},
@@ -66,7 +66,7 @@ Programmierung (KPS 2015)},
   month={June}
 } 
 
-@misc{mitre_ub,
+@misc{mitreub,
   title={CVE Records on Undefined Behavior Vulnerabilities},
   url={https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=undefined+behavior},
   year={2022}
@@ -121,13 +121,20 @@ Programming Language Design and Implementation},
   publisher={Wiley Online Library}
 }
 
-@misc{fermat_ub,
+@misc{fermatub,
   title={Undefined Behavior and Fermat's Last Theorem},
   url={https://web.archive.org/web/20201108094235/https://kukuruku.co/post/undefined-behavior-and-fermats-last-theorem/},
   year={2015},
   month={March}
 } 
 
+@misc{fnodeletelinux,
+  title={Add -fno-delete-null-pointer-checks to gcc CFLAGS},
+  url={https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a3ca86aea507904148870946d599e07a340b39bf},
+  year={2009},
+  month={July}
+} 
+
 @article{lee2017taming,
   title={Taming undefined behavior in LLVM},
   author={Lee, Juneyoung and Kim, Yoonseung and Song, Youngju and Hur,

TSW/contr.tex

@@ -2,10 +2,41 @@
 
 Given the little research done in the field of analying the performance
 of UB optimizations, this study aims to provide insights of the
-performance on a specific class of software applications, i.e. operating
-systems.
+performance of these optimizations on a specific class of software
+applications, i.e. operating systems.
 
-We take a self-contained operating system with focus on robustness and
+The first step of our work is to filter out all UB instances
+presented in the standard and focus on the UBs that present a potential
+for being used in compiler optimizations. Our filtering strategy is
+based on the assumption that all UBs that conflict with the
+intentionality of the progammer shall not be used to issue code
+optimizations.
+
+Then we modify the compiler implementation to turn off these
+optimizatoins. A preliminary list of such UB extracted from the standard
+is:
+\begin{itemize}
+\item An arithmetic operation is invalid (such as division or modulus by
+0) or produces a result that cannot be represented in the space provided
+(such as overflow or underflow) (\$3.3).
+\item An invalid array reference, null pointer reference, or reference
+to an object declared with automatic storage duration in a terminated
+block occurs (\$3.3.3.2).
+\item A pointer is converted to other than an integral or pointer type
+(\$3.3.4).  
+\end{itemize}
+
+\todo{talk here or somewhere else about the pratical consequences of UB
+optimizations}
+The first UB could lead to code being eliminated if the compiler detects
+that the arithmetic operation is incompatible with the
+standard~\cite{wang2012undefined}. The second UB could discard security
+checks for NULL pointers~\cite{fnodeletelinux} and the third UB could
+break manual optimizatoins on floating point
+numbers~\cite{lomont2003fast}.
+
+To analyze the role of these optimizations in real-life software, we
+take a self-contained operating system with focus on robustness and
 security, i.e. OpenBSD, and compile it on one hand with UB optimizations
 turned on and on the other hand with UB optimizations turned off. After
 this stage, the result will be two comparison canditates which will be

TSW/intro.tex

@@ -10,9 +10,9 @@ suddenly broken in newer versions because the standard imposes no
 requirements on undefined behavior.
 
 This has created serious security problems throughout the
-years~\cite{wang2012undefined,checks_2008}. A number of initiatives to
+years~\cite{wang2012undefined,checks2008}. A number of initiatives to
 solve this problem were started from different
-parties~\cite{google_2015,regehr_2014,wang2013towards} however the
+parties~\cite{google2015,regehr2014,wang2013towards} however the
 problem still persists. The primary open source developer groups have
 seized the unsteady definition of undefined behavior to justify
 dangerous slient code transformations that break the intention of the

TSW/main.tex

@@ -6,6 +6,7 @@
 \usepackage{textcomp}
 \usepackage{xcolor}
 \usepackage{listings}
+\usepackage{url}
 \def\BibTeX{{\rm B\kern-.05em{\sc i\kern-.025em b}\kern-.08em
     T\kern-.1667em\lower.7ex\hbox{E}\kern-.125emX}}