| author | Christian Urban <christian.urban@kcl.ac.uk> |
| Sat, 03 Dec 2022 21:58:47 +0000 | |
| changeset 902 | d516888e5878 |
| parent 901 | 01b481e47887 |
| child 939 | fb6ffb9b7304 |
| permissions | -rw-r--r-- |
| 701 | 1 |
% !TEX program = xelatex |
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\documentclass[dvipsnames,14pt,t,xelatex,aspectratio=169,xcolor={table}]{beamer}
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\usepackage{../slides}
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\usepackage{../langs}
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\usepackage{../data}
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\usepackage{../graphicss}
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\usepackage{../grammar}
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\usepackage{soul}
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\usepackage{mathpartir}
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\usetikzlibrary{shapes,arrows,shadows}
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% beamer stuff |
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\renewcommand{\slidecaption}{CFL 09, King's College London}
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\newcommand{\bl}[1]{\textcolor{blue}{#1}}
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\begin{document}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[t]
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\frametitle{%
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\begin{tabular}{@ {}c@ {}}
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\\[-3mm] |
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\LARGE Compilers and \\[-2mm] |
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\LARGE Formal Languages\\[-3mm] |
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\end{tabular}}
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\normalsize |
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\begin{center}
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\begin{tabular}{ll}
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Email: & christian.urban at kcl.ac.uk\\ |
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Office Hour: & Fridays 11 -- 12\\ |
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Location: & N7.07 (North Wing, Bush House)\\ |
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Slides \& Progs: & KEATS\\ |
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Pollev: & \texttt{\alert{https://pollev.com/cfltutoratki576}}\\
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\end{tabular}
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\end{center}
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\begin{center}
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\begin{tikzpicture}
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\node[drop shadow,fill=white,inner sep=0pt] |
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{\footnotesize\rowcolors{1}{capri!10}{white}
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\begin{tabular}{|p{4.8cm}|p{4.8cm}|}\hline
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1 Introduction, Languages & 6 While-Language \\ |
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2 Regular Expressions, Derivatives & 7 Compilation, JVM \\ |
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3 Automata, Regular Languages & 8 Compiling Functional Languages \\ |
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4 Lexing, Tokenising & \cellcolor{blue!50} 9 Optimisations \\
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5 Grammars, Parsing & 10 LLVM \\ \hline |
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\end{tabular}%
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}; |
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\end{tikzpicture}
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\end{center}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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||
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c,fragile]
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\frametitle{The Fun Language}
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\footnotesize |
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\begin{textblock}{13}(0.9,3)
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\begin{lstlisting}[numbers=none]
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def fib(n) = if n == 0 then 0 |
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else if n == 1 then 1 |
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else fib(n - 1) + fib(n - 2); |
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def fact(n) = if n == 0 then 1 else n * fact(n - 1); |
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def ack(m, n) = if m == 0 then n + 1 |
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else if n == 0 then ack(m - 1, 1) |
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else ack(m - 1, ack(m, n - 1)); |
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||
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def gcd(a, b) = if b == 0 then a else gcd(b, a % b); |
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\end{lstlisting}
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\end{textblock}
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| 609 | 76 |
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c, fragile]
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\frametitle{Stack Estimation}
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\small |
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\mbox{}\\[-15mm]
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\bl{\begin{center}
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\begin{tabular}{@{\hspace{-4mm}}l@{\hspace{2mm}}c@{\hspace{2mm}}l@{}}
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$\textit{estimate}(n)$ & $\dn$ & $1$\\
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$\textit{estimate}(x)$ & $\dn$ & $1$\\
|
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$\textit{estimate}(a_1\;aop\;a_2)$ & $\dn$ &
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$\textit{estimate}(a_1) + \textit{estimate}(a_2)$\\
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$\textit{estimate}(\pcode{if}\;b\;\pcode{then}\;e_1\;\pcode{else}\;e_2)$ & $\dn$ &
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$\textit{estimate}(b) +$\\
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& & $\quad max(\textit{estimate}(e_1), \textit{estimate}(e_2))$\\
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$\textit{estimate}(\pcode{write}(e))$ & $\dn$ &
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$\textit{estimate}(e) + 1$\\
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$\textit{estimate}(e_1 ; e_2)$ & $\dn$ &
|
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$max(\textit{estimate}(e_1), \textit{estimate}(e_2))$\\
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$\textit{estimate}(f(e_1, ..., e_n))$ & $\dn$ &
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$\sum_{i = 1..n}\;estimate(e_i)$\medskip\\
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$\textit{estimate}(a_1\;bop\;a_2)$ & $\dn$ &
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$\textit{estimate}(a_1) + \textit{estimate}(a_2)$\\
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\end{tabular}
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\end{center}}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c,fragile]
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\frametitle{\mbox{}\hspace{5cm}Factorial}
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\begin{textblock}{7}(0,1.0)\footnotesize
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\begin{minipage}{6cm}
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\begin{lstlisting}[language=JVMIS,basicstyle=\ttfamily, numbers=none]
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.method public static facT(II)I |
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.limit locals 2 |
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.limit stack 6 |
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iload 0 |
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ldc 0 |
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if_icmpne If_else_2 |
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iload 1 |
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goto If_end_3 |
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If_else_2: |
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iload 0 |
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ldc 1 |
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isub |
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iload 0 |
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iload 1 |
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imul |
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invokestatic fact/fact/facT(II)I |
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If_end_3: |
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ireturn |
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.end method |
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\end{lstlisting}
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\end{minipage}
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\end{textblock}
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\begin{textblock}{7}(6,7)
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\begin{bubble}[7cm]\small
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\begin{lstlisting}[language=Lisp,
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basicstyle=\ttfamily, |
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numbers=none, |
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xleftmargin=1mm,linebackgroundcolor=\color{cream}]
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def facT(n, acc) = |
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if n == 0 then acc |
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else facT(n - 1, n * acc); |
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\end{lstlisting}
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\end{bubble}
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\end{textblock}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[fragile]
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\begin{textblock}{7}(1,-0.2)\footnotesize
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\begin{minipage}{6cm}
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\begin{lstlisting}[language=JVMIS,basicstyle=\ttfamily, numbers=none, escapeinside={(*@}{@*)}]
|
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.method public static facT(II)I |
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.limit locals 2 |
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.limit stack 6 |
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(*@\hl{facT\_Start:} @*)
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iload 0 |
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ldc 0 |
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if_icmpne If_else_2 |
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iload 1 |
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goto If_end_3 |
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If_else_2: |
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iload 0 |
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ldc 1 |
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isub |
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iload 0 |
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iload 1 |
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imul |
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(*@\hl{istore 1} @*)
|
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(*@\hl{istore 0} @*)
|
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(*@\hl{goto facT\_Start} @*)
|
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If_end_3: |
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ireturn |
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.end method |
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\end{lstlisting}
|
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\end{minipage}
|
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\end{textblock}
|
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||
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\begin{textblock}{7}(6,7)
|
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\begin{bubble}[7cm]\small
|
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\begin{lstlisting}[language=Lisp,
|
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basicstyle=\ttfamily, |
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numbers=none, |
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xleftmargin=1mm,linebackgroundcolor=\color{cream}]
|
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def facT(n, acc) = |
|
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if n == 0 then acc |
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else facT(n - 1, n * acc); |
|
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\end{lstlisting}
|
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\end{bubble}
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\end{textblock}
|
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203 |
||
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\end{frame}
|
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
206 |
||
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
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\begin{frame}[t, fragile]
|
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\frametitle{Tail Recursion}
|
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210 |
||
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A call to \texttt{f(args)} is usually compiled as\medskip
|
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212 |
||
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{\small\begin{lstlisting}[basicstyle=\ttfamily, numbers=none]
|
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args onto stack |
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invokestatic .../f |
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\end{lstlisting}}\pause
|
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||
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||
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A call is in tail position provided:\medskip |
|
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||
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{\small\begin{itemize}
|
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\item \texttt{if Bexp then \hl{Exp} else \hl{Exp}}
|
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\item \texttt{Exp ; \hl{Exp}}
|
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\item \texttt{Exp op Exp}
|
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\end{itemize}}\medskip
|
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||
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then a call \texttt{f(args)} can be compiled as\medskip\small
|
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||
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\begin{lstlisting}[numbers=none]
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prepare environment |
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jump to start of function |
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\end{lstlisting}
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||
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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||
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c, fragile]
|
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\frametitle{Tail Recursive Call}
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\footnotesize |
|
241 |
||
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\begin{textblock}{13}(-0.3,3)
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\begin{lstlisting}[language=Scala, numbers=none]
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def compile_expT(a: Exp, env: Mem, name: String): Instrs = |
|
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... |
|
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case Call(n, args) => if (name == n) |
|
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{
|
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val stores = |
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args.zipWithIndex.map { case (x, y) => i"istore $y" }
|
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||
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args.map(a => compile_expT(a, env, "")).mkString ++ |
|
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stores.reverse.mkString ++ |
|
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i"goto ${n}_Start"
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} else {
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val is = "I" * args.length |
|
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args.map(a => compile_expT(a, env, "")).mkString ++ |
|
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i"invokestatic XXX/XXX/${n}(${is})I"
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} |
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\end{lstlisting}
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\end{textblock}
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||
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\end{frame}
|
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\begin{frame}[c,fragile]
|
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\frametitle{Peephole Optimisations}
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| 609 | 268 |
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\begin{center}
|
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\begin{tabular}{ll}
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\texttt{ldc}: & \texttt{iconst\_0} \ldots \texttt{iconst\_5}\\
|
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& \texttt{bipush} $n$ where $-128 < n <= 128$\bigskip\\
|
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\texttt{iload}: & \texttt{iload\_0} \ldots \texttt{iload\_3}\bigskip\\
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\texttt{istore}: & \texttt{istore\_0} \ldots \texttt{istore\_3}\\
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\end{tabular}
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\end{center}
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\end{frame}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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%\begin{frame}[c,fragile]
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%\frametitle{Factorial Funct.~on the JVM}
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% |
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%\begin{textblock}{7}(1,1.8)\footnotesize
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%\begin{minipage}{6cm}
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%\begin{lstlisting}[language=JVMIS,basicstyle=\ttfamily, numbers=none]
|
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%.method public static facT(II)I |
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%.limit locals 2 |
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%.limit stack 6 |
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% iload 0 |
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% ldc 0 |
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% if_icmpne If_else_2 |
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% iload 1 |
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% goto If_end_3 |
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%If_else_2: |
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% iload 0 |
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% ldc 1 |
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% isub |
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% iload 0 |
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% iload 1 |
|
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% imul |
|
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% invokestatic fact/fact/facT(II)I |
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%If_end_3: |
|
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% ireturn |
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%.end method |
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%\end{lstlisting}
|
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%\end{minipage}
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%\end{textblock}
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% |
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%\begin{textblock}{7}(6,7)
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%\begin{bubble}[7cm]\small
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%\begin{lstlisting}[language=Lisp,
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% basicstyle=\ttfamily, |
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% numbers=none, |
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% xleftmargin=1mm,linebackgroundcolor=\color{cream}]
|
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%def facT(n, acc) = |
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% if n == 0 then acc |
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% else facT(n - 1, n * acc); |
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%\end{lstlisting}
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%\end{bubble}
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%\end{textblock}
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% |
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%\end{frame}
|
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
327 |
||
328 |
||
329 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
| 701 | 330 |
\begin{frame}[fragile,c]
|
331 |
\frametitle{LLVM}
|
|
| 609 | 332 |
|
333 |
\begin{itemize}
|
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| 701 | 334 |
\item Chris Lattner, Vikram Adve (started in 2000) |
335 |
\item Apple hired Lattner in 2006 |
|
336 |
\item modular architecture, LLVM-IR |
|
337 |
\item \texttt{lli} and \texttt{llc}
|
|
338 |
\end{itemize}
|
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| 609 | 339 |
|
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\end{frame}
|
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| 701 | 341 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
342 |
||
343 |
||
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||
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\tikzstyle{sensor}=[draw, fill=blue!20, text width=3.8em, line width=1mm,
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text centered, minimum height=2em,drop shadow] |
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\tikzstyle{ann} = [above, text width=4em, text centered]
|
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\tikzstyle{sc} = [sensor, text width=7em, fill=red!20,
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minimum height=6em, rounded corners, drop shadow,line width=1mm] |
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||
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\begin{frame}[fragile,c]
|
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353 |
\frametitle{LLVM: Overview}
|
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354 |
||
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\begin{tikzpicture}
|
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356 |
% Validation Layer is the same except that there are a set of nodes and links which are added |
|
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||
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\path (0,0) node (IR) [sc] {\textbf{LLVM-IR}\\ Optimisations};
|
|
359 |
\path (IR.west)+(-2.2,1.7) node (sou1) [sensor] {C++};
|
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\path (IR.west)+(-2.2,0.5) node (sou2)[sensor] {C};
|
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361 |
\path (IR.west)+(-2.2,-1.0) node (dots)[ann] {$\vdots$};
|
|
362 |
\path (IR.west)+(-2.2,-1.8) node (sou3)[sensor] {Haskell};
|
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363 |
||
364 |
\path [draw,->,line width=1mm] (sou1.east) -- node [above] {} (IR.160);
|
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\path [draw,->,line width=1mm] (sou2.east) -- node [above] {} (IR.180);
|
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\path [draw,->,line width=1mm] (sou3.east) -- node [above] {} (IR.200);
|
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||
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\path (IR.east)+(2.2,2.0) node (tar1)[sensor] {x86};
|
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\path (IR.east)+(2.2,0.8) node (tar2)[sensor] {ARM};
|
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\path (IR.east)+(2.2,-0.4) node (tar3)[sensor] {MIPS};
|
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371 |
\path (IR.east)+(2.2,-1.6) node (tar4)[sensor] {RISC};
|
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372 |
\path (IR.east)+(2.2,-2.8) node (tar5)[sensor] {Power PC};
|
|
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\path (IR.east)+(2.2,-4.2) node (dots2)[ann] {$\vdots$};
|
|
374 |
||
375 |
\path [draw,<-,line width=1mm] (tar1.west) -- node [above] {} (IR.10);
|
|
376 |
\path [draw,<-,line width=1mm] (tar2.west) -- node [above] {} (IR.5);
|
|
377 |
\path [draw,<-,line width=1mm] (tar3.west) -- node [above] {} (IR.0);
|
|
378 |
\path [draw,<-,line width=1mm] (tar4.west) -- node [above] {} (IR.-5);
|
|
379 |
\path [draw,<-,line width=1mm] (tar5.west) -- node [above] {} (IR.-10);
|
|
380 |
||
381 |
\end{tikzpicture}
|
|
382 |
\end{frame}
|
|
383 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
384 |
||
| 609 | 385 |
|
386 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
| 701 | 387 |
\begin{frame}[fragile,t]
|
388 |
\frametitle{LLVM-IR}
|
|
389 |
\small |
|
390 |
||
391 |
\begin{textblock}{7.7}(8,11.4)
|
|
392 |
\begin{bubble}[5cm]\small
|
|
393 |
\begin{lstlisting}[language=Lisp,
|
|
394 |
numbers=none, |
|
395 |
xleftmargin=1mm,linebackgroundcolor=\color{cream}]
|
|
396 |
def fact(n) = |
|
397 |
if n == 0 then 1 |
|
398 |
else n * fact(n - 1) |
|
399 |
\end{lstlisting}
|
|
400 |
\end{bubble}
|
|
401 |
\end{textblock}
|
|
|
310
d384fe01d0e8
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
309
diff
changeset
|
402 |
|
| 701 | 403 |
\begin{lstlisting}[language=LLVM,xleftmargin=-7mm]
|
404 |
define i32 @fact (i32 %n) {
|
|
405 |
%tmp_19 = icmp eq i32 %n, 0 |
|
406 |
br i1 %tmp_19, label %if_br_23, label %else_br_24 |
|
407 |
||
408 |
if_br_23: |
|
409 |
ret i32 1 |
|
410 |
||
411 |
else_br_24: |
|
412 |
%tmp_21 = sub i32 %n, 1 |
|
413 |
%tmp_22 = call i32 @fact (i32 %tmp_21) |
|
414 |
%tmp_20 = mul i32 %n, %tmp_22 |
|
415 |
ret i32 %tmp_20 |
|
416 |
} |
|
417 |
\end{lstlisting}
|
|
| 609 | 418 |
|
419 |
\end{frame}
|
|
| 701 | 420 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
421 |
||
422 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
423 |
\begin{frame}[fragile,c]
|
|
424 |
\frametitle{LLVM Types}
|
|
425 |
||
426 |
\tt |
|
427 |
\begin{center}
|
|
428 |
\begin{tabular}{ll}
|
|
429 |
boolean & i1 \\ |
|
430 |
byte & i8 \\ |
|
431 |
short & i16\\ |
|
432 |
char & i16\\ |
|
433 |
integer & i32\\ |
|
434 |
long & i64\\ |
|
435 |
float & float\\ |
|
436 |
double & double\\ |
|
437 |
*\_ & pointer to \\ |
|
438 |
**\_ & pointer to a pointer to\\ |
|
439 |
\mbox{}[\_] & arrays of\\
|
|
440 |
\end{tabular}
|
|
441 |
\end{center}
|
|
442 |
||
443 |
\end{frame}
|
|
444 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
445 |
||
446 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
447 |
\begin{frame}[fragile,c]
|
|
| 702 | 448 |
\frametitle{LLVM-IR Instructions}
|
| 701 | 449 |
\small |
450 |
||
| 702 | 451 |
\begin{lstlisting}[language=LLVM,xleftmargin=0mm]
|
| 701 | 452 |
br i1 %var, label %if_br, label %else_br |
453 |
||
454 |
icmp eq i32 %x, %y ; for equal |
|
455 |
icmp sle i32 %x, %y ; signed less or equal |
|
456 |
icmp slt i32 %x, %y ; signed less than |
|
457 |
icmp ult i32 %x, %y ; unsigned less than |
|
458 |
||
459 |
%var = call i32 @foo(...args...) |
|
460 |
\end{lstlisting}
|
|
461 |
||
462 |
\end{frame}
|
|
463 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
464 |
||
465 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
466 |
\begin{frame}[fragile,c]
|
|
467 |
\frametitle{SSA Format}
|
|
468 |
||
469 |
\bl{$(1 + a) + (3 + (b * 5))$}\bigskip\bigskip
|
|
470 |
||
471 |
\begin{lstlisting}[language=LLVM]
|
|
| 702 | 472 |
tmp0 = add 1 a |
473 |
tmp1 = mul b 5 |
|
474 |
tmp2 = add 3 tmp1 |
|
475 |
tmp3 = add tmp0 tmp2 |
|
476 |
\end{lstlisting}\bigskip\bigskip
|
|
477 |
||
478 |
\hfill Static Single Assignment |
|
| 701 | 479 |
|
480 |
\end{frame}
|
|
481 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
| 609 | 482 |
|
483 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
| 701 | 484 |
\begin{frame}[fragile,c]
|
485 |
\frametitle{Abstract Syntax Trees}
|
|
486 |
\footnotesize |
|
487 |
||
488 |
\begin{lstlisting}[language=Scala,numbers=none,xleftmargin=-3mm]
|
|
489 |
// Fun language (expressions) |
|
490 |
abstract class Exp |
|
491 |
abstract class BExp |
|
492 |
||
493 |
case class Call(name: String, args: List[Exp]) extends Exp |
|
494 |
case class If(a: BExp, e1: Exp, e2: Exp) extends Exp |
|
495 |
case class Write(e: Exp) extends Exp |
|
496 |
case class Var(s: String) extends Exp |
|
497 |
case class Num(i: Int) extends Exp |
|
498 |
case class Aop(o: String, a1: Exp, a2: Exp) extends Exp |
|
499 |
case class Sequence(e1: Exp, e2: Exp) extends Exp |
|
500 |
case class Bop(o: String, a1: Exp, a2: Exp) extends BExp |
|
501 |
\end{lstlisting}
|
|
| 609 | 502 |
|
| 701 | 503 |
\end{frame}
|
504 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
505 |
||
506 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
507 |
\begin{frame}[fragile,c]
|
|
508 |
\frametitle{K-(Intermediate)Language}
|
|
509 |
\footnotesize |
|
| 609 | 510 |
|
| 701 | 511 |
\begin{lstlisting}[language=Scala,numbers=none,xleftmargin=-3mm]
|
512 |
abstract class KExp |
|
513 |
abstract class KVal |
|
514 |
||
| 702 | 515 |
// K-Values |
| 701 | 516 |
case class KVar(s: String) extends KVal |
517 |
case class KNum(i: Int) extends KVal |
|
518 |
case class Kop(o: String, v1: KVal, v2: KVal) extends KVal |
|
519 |
case class KCall(o: String, vrs: List[KVal]) extends KVal |
|
520 |
case class KWrite(v: KVal) extends KVal |
|
521 |
||
| 702 | 522 |
// K-Expressions |
| 701 | 523 |
case class KIf(x1: String, e1: KExp, e2: KExp) extends KExp |
524 |
case class KLet(x: String, v: KVal, e: KExp) extends KExp |
|
525 |
case class KReturn(v: KVal) extends KExp |
|
| 609 | 526 |
\end{lstlisting}
|
527 |
||
| 701 | 528 |
\end{frame}
|
529 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
530 |
||
531 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
532 |
\begin{frame}[fragile,c]
|
|
| 819 | 533 |
\frametitle{KLet}
|
534 |
||
535 |
\begin{lstlisting}[language=LLVM]
|
|
536 |
tmp0 = add 1 a |
|
537 |
tmp1 = mul b 5 |
|
538 |
tmp2 = add 3 tmp1 |
|
539 |
tmp3 = add tmp0 tmp2 |
|
540 |
\end{lstlisting}
|
|
541 |
||
542 |
\begin{lstlisting}[language=LLVMIR]
|
|
543 |
KLet tmp0 , add 1 a in |
|
544 |
KLet tmp1 , mul b 5 in |
|
545 |
KLet tmp2 , add 3 tmp1 in |
|
546 |
KLet tmp3 , add tmp0 tmp2 in |
|
547 |
... |
|
548 |
\end{lstlisting}
|
|
549 |
||
550 |
\begin{lstlisting}[language=Scala,numbers=none]
|
|
551 |
case class KLet(x: String, e1: KVal, e2: KExp) |
|
552 |
\end{lstlisting}
|
|
553 |
||
554 |
\end{frame}
|
|
555 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
556 |
||
557 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
558 |
\begin{frame}[fragile,c]
|
|
559 |
\frametitle{KLet}
|
|
560 |
||
561 |
\begin{lstlisting}[language=LLVM]
|
|
562 |
tmp0 = add 1 a |
|
563 |
tmp1 = mul b 5 |
|
564 |
tmp2 = add 3 tmp1 |
|
565 |
tmp3 = add tmp0 tmp2 |
|
566 |
\end{lstlisting}
|
|
567 |
||
568 |
\begin{lstlisting}[language=LLVMIR]
|
|
569 |
let tmp0 = add 1 a in |
|
570 |
let tmp1 = mul b 5 in |
|
571 |
let tmp2 = add 3 tmp1 in |
|
572 |
let tmp3 = add tmp0 tmp2 in |
|
573 |
... |
|
574 |
\end{lstlisting}
|
|
575 |
||
576 |
\begin{lstlisting}[language=Scala,numbers=none]
|
|
577 |
case class KLet(x: String, e1: KVal, e2: KExp) |
|
578 |
\end{lstlisting}
|
|
579 |
||
580 |
\end{frame}
|
|
581 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
582 |
||
583 |
||
584 |
||
585 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
586 |
\begin{frame}[fragile,c]
|
|
| 701 | 587 |
\frametitle{CPS-Translation}
|
588 |
\small |
|
589 |
||
590 |
\begin{lstlisting}[language=Scala,numbers=none]
|
|
591 |
def CPS(e: Exp)(k: KVal => KExp) : KExp = |
|
592 |
e match { ... }
|
|
593 |
\end{lstlisting}
|
|
594 |
\bigskip\bigskip |
|
595 |
||
| 702 | 596 |
the continuation \texttt{k} can be thought of:\medskip
|
597 |
||
| 701 | 598 |
\small |
599 |
\begin{lstlisting}[language=LLVMIR,numbers=none,xleftmargin=30mm,escapeinside={(*@}{@*)}]
|
|
600 |
let tmp0 = add 1 a in |
|
601 |
let tmp1 = mul (*@$\Box$@*) 5 in |
|
602 |
let tmp2 = add 3 tmp1 in |
|
603 |
let tmp3 = add tmp0 tmp2 in |
|
604 |
KReturn tmp3 |
|
605 |
\end{lstlisting}
|
|
| 609 | 606 |
|
607 |
\end{frame}
|
|
| 701 | 608 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
609 |
||
610 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
611 |
\begin{frame}[fragile,c]
|
|
612 |
\frametitle{CPS-Translation}
|
|
613 |
\small |
|
614 |
||
615 |
\begin{lstlisting}[language=Scala,numbers=none]
|
|
616 |
def CPS(e: Exp)(k: KVal => KExp) : KExp = |
|
617 |
e match {
|
|
618 |
case Var(s) => k(KVar(s)) |
|
619 |
case Num(i) => k(KNum(i)) |
|
620 |
... |
|
621 |
} |
|
622 |
\end{lstlisting}
|
|
623 |
\bigskip\bigskip |
|
624 |
||
625 |
\small |
|
626 |
\begin{lstlisting}[language=LLVMIR,numbers=none,xleftmargin=30mm,escapeinside={(*@}{@*)}]
|
|
627 |
let tmp0 = add 1 a in |
|
628 |
let tmp1 = mul (*@$\Box$@*) 5 in |
|
629 |
let tmp2 = add 3 tmp1 in |
|
630 |
let tmp3 = add tmp0 tmp2 in |
|
631 |
KReturn tmp3 |
|
632 |
\end{lstlisting}
|
|
633 |
||
634 |
\end{frame}
|
|
635 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
| 609 | 636 |
|
637 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
| 701 | 638 |
\begin{frame}[fragile,c]
|
639 |
\frametitle{CPS-Translation}
|
|
640 |
\small |
|
| 609 | 641 |
|
| 701 | 642 |
\begin{lstlisting}[language=Scala,numbers=none,xleftmargin=-5mm]
|
643 |
def CPS(e: Exp)(k: KVal => KExp) : KExp = e match {
|
|
644 |
case Aop(o, e1, e2) => {
|
|
645 |
val z = Fresh("tmp")
|
|
646 |
CPS(e1)(y1 => |
|
647 |
CPS(e2)(y2 => |
|
648 |
KLet(z, Kop(o, y1, y2), k(KVar(z))))) |
|
649 |
} ... |
|
650 |
} |
|
| 609 | 651 |
\end{lstlisting}
|
| 702 | 652 |
\mbox{}\\[-8mm]%
|
653 |
% |
|
| 701 | 654 |
\begin{lstlisting}[language=LLVMIR,numbers=none,xleftmargin=30mm,escapeinside={(*@}{@*)}]
|
655 |
... |
|
656 |
let z = op (*@$\Box_{y_1}$@*) (*@$\Box_{y_2}$@*)
|
|
657 |
let tmp0 = add 1 a in |
|
| 702 | 658 |
let tmp1 = mul (*@$\Box\!\!\!\!\raisebox{0.6mm}{\alert{\texttt{z}}}$@*) 5 in
|
| 701 | 659 |
let tmp2 = add 3 tmp1 in |
660 |
let tmp3 = add tmp0 tmp2 in |
|
661 |
KReturn tmp3 |
|
662 |
\end{lstlisting}
|
|
| 609 | 663 |
|
664 |
\end{frame}
|
|
| 701 | 665 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 609 | 666 |
|
667 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
| 701 | 668 |
\begin{frame}[fragile,c]
|
669 |
\frametitle{CPS-Translation}
|
|
670 |
\small |
|
| 609 | 671 |
|
| 701 | 672 |
\begin{lstlisting}[language=Scala,numbers=none]
|
673 |
def CPS(e: Exp)(k: KVal => KExp) : KExp = |
|
674 |
e match {
|
|
675 |
case Sequence(e1, e2) => |
|
676 |
CPS(e1)(_ => CPS(e2)(y2 => k(y2))) |
|
677 |
... |
|
678 |
} |
|
679 |
\end{lstlisting}
|
|
| 702 | 680 |
\bigskip |
| 701 | 681 |
|
682 |
\small |
|
683 |
\begin{lstlisting}[language=LLVMIR,numbers=none,xleftmargin=30mm,escapeinside={(*@}{@*)}]
|
|
684 |
let tmp0 = add 1 a in |
|
685 |
let tmp1 = mul (*@$\Box$@*) 5 in |
|
686 |
let tmp2 = add 3 tmp1 in |
|
687 |
let tmp3 = add tmp0 tmp2 in |
|
688 |
KReturn tmp3 |
|
689 |
\end{lstlisting}
|
|
| 609 | 690 |
|
691 |
\end{frame}
|
|
| 701 | 692 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
310
d384fe01d0e8
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
309
diff
changeset
|
693 |
|
| 610 | 694 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 701 | 695 |
\begin{frame}[fragile,c]
|
696 |
\frametitle{CPS-Translation}
|
|
697 |
\small |
|
698 |
||
699 |
\begin{lstlisting}[language=Scala,numbers=none,xleftmargin=-3mm]
|
|
700 |
def CPS(e: Exp)(k: KVal => KExp) : KExp = |
|
701 |
e match {
|
|
702 |
... |
|
703 |
case If(Bop(o, b1, b2), e1, e2) => {
|
|
704 |
val z = Fresh("tmp")
|
|
705 |
CPS(b1)(y1 => |
|
706 |
CPS(b2)(y2 => |
|
707 |
KLet(z, Kop(o, y1, y2), |
|
708 |
KIf(z, CPS(e1)(k), CPS(e2)(k))))) |
|
709 |
} |
|
710 |
... |
|
711 |
} |
|
712 |
\end{lstlisting}
|
|
713 |
||
714 |
\end{frame}
|
|
715 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
716 |
||
| 702 | 717 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
718 |
\begin{frame}[c,fragile]
|
|
719 |
\frametitle{The Basic Language, 1980+}
|
|
720 |
||
721 |
\begin{lstlisting}[language={[Visual]Basic},numbers=none]
|
|
722 |
5 LET S = 0 |
|
723 |
10 INPUT V |
|
724 |
20 PRINT "Input number" |
|
725 |
30 IF N = 0 THEN GOTO 99 |
|
726 |
40 FOR I = 1 TO N |
|
727 |
45 LET S = S + V(I) |
|
728 |
50 NEXT I |
|
729 |
60 PRINT S/N |
|
730 |
70 GOTO 5 |
|
731 |
99 END |
|
732 |
\end{lstlisting}
|
|
733 |
||
734 |
\hfill ``Spaghetti Code'' |
|
735 |
\end{frame}
|
|
736 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
737 |
||
738 |
||
739 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
740 |
\begin{frame}[c,fragile]
|
|
741 |
\frametitle{Target Specific ASM}
|
|
742 |
||
743 |
\begin{lstlisting}[language={},numbers=none]
|
|
744 |
llc -march=x86-64 fact.ll |
|
745 |
llc -march=arm fact.ll |
|
746 |
||
747 |
||
748 |
Intel: xorl %eax, %eax |
|
749 |
ARM: mov pc, lr |
|
750 |
\end{lstlisting}
|
|
751 |
||
752 |
\end{frame}
|
|
753 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
| 701 | 754 |
|
755 |
||
756 |
||
757 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
| 610 | 758 |
\begin{frame}[c]
|
759 |
||
760 |
\large\bf |
|
| 701 | 761 |
Using a compiler, \\ |
762 |
how can you mount the\\ |
|
763 |
perfect attack against a system? |
|
| 610 | 764 |
|
| 701 | 765 |
\end{frame}
|
| 610 | 766 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
767 |
||
768 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
769 |
\mode<presentation>{
|
|
770 |
\begin{frame}[c]
|
|
771 |
||
772 |
{\large\bf
|
|
773 |
What is a \alert{perfect} attack?}\bigskip
|
|
774 |
||
775 |
\begin{enumerate}
|
|
776 |
\item you can potentially completely take over a target system |
|
777 |
\item your attack is (nearly) undetectable |
|
778 |
\item the victim has (almost) no chance to recover |
|
779 |
\end{enumerate}
|
|
780 |
||
781 |
\end{frame}}
|
|
782 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
783 |
||
784 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
785 |
\mode<presentation>{
|
|
786 |
\begin{frame}[c]
|
|
787 |
||
788 |
||
789 |
\begin{center}
|
|
790 |
\begin{tikzpicture}[scale=1]
|
|
791 |
||
792 |
\onslide<1->{
|
|
793 |
\node (A) at (0,0) [draw=black, rectangle, very thick, minimum height=18mm, minimum width=17mm] {};
|
|
794 |
\node [below right] at (A.north west) {\footnotesize\begin{tabular}{@{}l@{}}
|
|
795 |
\only<1,2>{clean}\only<3->{\alert{hacked}}\\compiler\end{tabular}};}
|
|
796 |
||
797 |
||
798 |
\onslide<2->{
|
|
799 |
\node (B) at (-2,2) [draw=black, rectangle, very thick, minimum height=10mm, minimum width=12mm] {};
|
|
800 |
\node [below right] at (B.north west) {\footnotesize\begin{tabular}{@{}l@{}}login\\(src)\end{tabular}};
|
|
801 |
||
802 |
\node (C) at (2,2) [draw=black, rectangle, very thick, minimum height=10mm, minimum width=12mm] {};
|
|
803 |
\node [below right] at (C.north west) {\footnotesize\begin{tabular}{@{}l@{}}login\\(bin)\end{tabular}};
|
|
804 |
||
805 |
\draw[->, line width=2mm] (B) -- (C); |
|
806 |
} |
|
807 |
||
808 |
\onslide<3->{\node [above left=-1.5mm] at (C.south east) {\footnotesize \alert{$\blacksquare$}};}
|
|
809 |
||
810 |
\end{tikzpicture}
|
|
811 |
\end{center}
|
|
812 |
||
813 |
\end{frame}}
|
|
814 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
815 |
||
816 |
||
817 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
818 |
\mode<presentation>{
|
|
819 |
\begin{frame}[c]
|
|
820 |
||
821 |
\begin{center}
|
|
822 |
\begin{tikzpicture}[scale=1]
|
|
823 |
||
824 |
\onslide<1->{
|
|
825 |
\node (A) at (0,0) [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
|
|
826 |
\node [below right] at (A.north west) {\small V0.01};
|
|
827 |
\node [below right] (A1) at (A.south west) {\small Scala};
|
|
828 |
\node [below right] (A1) at (A1.south west) {\small\textcolor{gray}{host language}};
|
|
829 |
\node [above right] at (A.north west) {my compiler (src)};}
|
|
830 |
||
831 |
\onslide<2->{
|
|
832 |
\node (B) at (1.8,0) [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
|
|
833 |
\node [below right] at (B.north west) {\small V0.02};
|
|
834 |
\node [below right] at (B.south west) {\small Scala};
|
|
835 |
\node at (3,0) {\ldots};
|
|
836 |
||
837 |
\node (C) at (5,0) [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
|
|
838 |
\node [below right] at (C.north west) {\small V1.00};
|
|
839 |
\node [below right] at (C.south west) {\small Scala};}
|
|
840 |
||
841 |
\onslide<3->{
|
|
842 |
\node (D) at (6.8,0) [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
|
|
843 |
\node [below right] at (D.north west) {\small V1.00};
|
|
844 |
||
845 |
\node (E) at (6.8,2) [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
|
|
846 |
\node [below right] at (E.north west) {\small V1.01};}
|
|
847 |
||
848 |
\onslide<4->{
|
|
849 |
\node (F) at (8.6,0) [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
|
|
850 |
\node [below right] at (F.north west) {\small V1.01};
|
|
851 |
||
852 |
\node (G) at (8.6,2) [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
|
|
853 |
\node [below right] at (G.north west) {\small V1.02};
|
|
854 |
\node at (9.8,0) {\ldots};
|
|
855 |
\node at (9.8,2) {\ldots};
|
|
856 |
\node at (8,-2) {\textcolor{gray}{\begin{tabular}{@{}l@{}}no host language\\needed\end{tabular}}};
|
|
857 |
} |
|
858 |
||
859 |
\end{tikzpicture}
|
|
860 |
\end{center}
|
|
861 |
||
862 |
\end{frame}}
|
|
863 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
864 |
||
865 |
||
866 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
867 |
\mode<presentation>{
|
|
868 |
\begin{frame}<1-3>
|
|
869 |
\frametitle{\LARGE\begin{tabular}{c}Hacking Compilers
|
|
870 |
\end{tabular}}
|
|
871 |
||
872 |
%Why is it so paramount to have a small trusted code base (TCB)? |
|
873 |
\bigskip\bigskip |
|
874 |
||
875 |
\begin{columns}
|
|
876 |
\begin{column}{2.7cm}
|
|
877 |
\begin{minipage}{2.5cm}%
|
|
878 |
\begin{tabular}{c@ {}}
|
|
879 |
\includegraphics[scale=0.2]{../pics/ken-thompson.jpg}\\[-1.8mm]
|
|
880 |
\footnotesize Ken Thompson\\[-1.8mm] |
|
881 |
\footnotesize Turing Award, 1983\\ |
|
882 |
\end{tabular}
|
|
883 |
\end{minipage}
|
|
884 |
\end{column}
|
|
885 |
\begin{column}{9cm}
|
|
886 |
\begin{tabular}{l@ {\hspace{1mm}}p{8cm}}
|
|
887 |
||
888 |
& Ken Thompson showed how to hide a Trojan Horse in a |
|
889 |
compiler \textcolor{red}{without} leaving any traces in the source code.\\[2mm]
|
|
890 |
||
891 |
& No amount of source level verification will protect |
|
892 |
you from such Thompson-hacks.\\[2mm] |
|
893 |
||
894 |
\end{tabular}
|
|
895 |
\end{column}
|
|
896 |
\end{columns}
|
|
897 |
||
898 |
\only<2>{
|
|
899 |
\begin{textblock}{6}(4,2)
|
|
900 |
\begin{tikzpicture}
|
|
901 |
\draw (0,0) node[inner sep=3mm,fill=cream, ultra thick, draw=red, rounded corners=2mm] |
|
902 |
{\normalsize
|
|
903 |
\begin{minipage}{8cm}
|
|
904 |
\begin{quote}
|
|
905 |
\includegraphics[scale=0.05]{../pics/evil.png}
|
|
906 |
\begin{enumerate}
|
|
907 |
\item[1)] Assume you ship the compiler as binary and also with sources. |
|
908 |
\item[2)] Make the compiler aware when it compiles itself. |
|
909 |
\item[3)] Add the Trojan horse. |
|
910 |
\item[4)] Compile. |
|
911 |
\item[5)] Delete Trojan horse from the sources of the compiler. |
|
912 |
\item[6)] Go on holiday for the rest of your life. ;o)\\[-7mm]\mbox{}
|
|
913 |
\end{enumerate}
|
|
914 |
\end{quote}
|
|
915 |
\end{minipage}};
|
|
916 |
\end{tikzpicture}
|
|
917 |
\end{textblock}}
|
|
918 |
||
919 |
\end{frame}}
|
|
920 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
921 |
||
| 701 | 922 |
|
923 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
924 |
\begin{frame}[c]
|
|
925 |
\frametitle{Dijkstra on Testing}
|
|
926 |
||
927 |
\begin{bubble}[10cm]
|
|
928 |
``Program testing can be a very effective way to show the |
|
929 |
presence of bugs, but it is hopelessly inadequate for showing |
|
930 |
their absence.'' |
|
931 |
\end{bubble}\bigskip
|
|
932 |
||
933 |
\small |
|
934 |
What is good about compilers: the either seem to work, |
|
935 |
or go horribly wrong (most of the time). |
|
936 |
||
937 |
\end{frame}
|
|
938 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
939 |
||
940 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
941 |
\begin{frame}[c]
|
|
942 |
\frametitle{\Large Proving Programs to be Correct}
|
|
943 |
||
944 |
\begin{bubble}[10cm]
|
|
945 |
\small |
|
946 |
{\bf Theorem:} There are infinitely many prime
|
|
947 |
numbers.\medskip\\ |
|
948 |
||
949 |
{\bf Proof} \ldots\\
|
|
950 |
\end{bubble}\bigskip
|
|
951 |
||
952 |
||
953 |
similarly\bigskip |
|
954 |
||
955 |
\begin{bubble}[10cm]
|
|
956 |
\small |
|
957 |
{\bf Theorem:} The program is doing what
|
|
958 |
it is supposed to be doing.\medskip |
|
959 |
||
960 |
{\bf Long, long proof} \ldots\\
|
|
961 |
\end{bubble}\bigskip\medskip
|
|
962 |
||
963 |
\small This can be a gigantic proof. The only hope is to have |
|
964 |
help from the computer. `Program' is here to be understood to be |
|
965 |
quite general (compiler, OS, \ldots). |
|
966 |
||
967 |
\end{frame}
|
|
968 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
969 |
||
970 |
||
971 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
972 |
||
973 |
\begin{frame}[c]
|
|
974 |
\frametitle{Can This Be Done?}
|
|
975 |
||
976 |
\begin{itemize}
|
|
977 |
\item in 2008, verification of a small C-compiler |
|
978 |
\begin{itemize}
|
|
979 |
\item ``if my input program has a certain behaviour, then the compiled machine code has the same behaviour'' |
|
980 |
\item is as good as \texttt{gcc -O1}, but much, much less buggy
|
|
981 |
\end{itemize}
|
|
982 |
\end{itemize}
|
|
983 |
||
984 |
\begin{center}
|
|
985 |
\includegraphics[scale=0.12]{../pics/compcert.png}
|
|
986 |
\end{center}
|
|
987 |
||
988 |
\end{frame}
|
|
989 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
990 |
||
991 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
992 |
\begin{frame}[t]
|
|
993 |
\frametitle{Fuzzy Testing C-Compilers}
|
|
994 |
||
995 |
\begin{itemize}
|
|
996 |
\item tested GCC, LLVM and others by randomly generating |
|
997 |
C-programs |
|
998 |
\item found more than 300 bugs in GCC and also |
|
999 |
many in LLVM (some of them highest-level critical)\bigskip |
|
1000 |
\item about CompCert: |
|
1001 |
||
1002 |
\begin{bubble}[10.7cm]\small ``The striking thing about our CompCert
|
|
1003 |
results is that the middle-end bugs we found in all other |
|
1004 |
compilers are absent. As of early 2011, the under-development |
|
1005 |
version of CompCert is the only compiler we have tested for |
|
1006 |
which Csmith cannot find wrong-code errors. This is not for |
|
1007 |
lack of trying: we have devoted about six CPU-years to the |
|
1008 |
task.'' |
|
1009 |
\end{bubble}
|
|
1010 |
\end{itemize}
|
|
1011 |
||
1012 |
\end{frame}
|
|
1013 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1014 |
||
1015 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1016 |
||
1017 |
\begin{frame}[c]
|
|
1018 |
\frametitle{Next Week}
|
|
1019 |
||
1020 |
\begin{itemize}
|
|
1021 |
\item Revision Lecture\medskip |
|
1022 |
\item How many strings are in $\bl{L(a^*)}$?\pause\medskip
|
|
1023 |
\item How many strings are in $\bl{L((a + b)^*)}$?\\ Are there more than
|
|
1024 |
in $\bl{L(a^*)}$?
|
|
1025 |
\end{itemize}
|
|
1026 |
||
1027 |
||
1028 |
||
1029 |
\end{frame}
|
|
1030 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1031 |
||
| 822 | 1032 |
\begin{frame}<1-20>[c]
|
1033 |
\end{frame}
|
|
| 701 | 1034 |
|
1035 |
\end{document}
|
|
1036 |
||
1037 |
%%% Local Variables: |
|
1038 |
%%% mode: latex |
|
1039 |
%%% TeX-master: t |
|
1040 |
%%% End: |
|
1041 |
||
1042 |
||
1043 |
||
1044 |
||
1045 |
||
| 610 | 1046 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
1047 |
\begin{frame}[c]
|
|
1048 |
||
1049 |
\begin{center}
|
|
1050 |
\includegraphics[scale=0.6]{../pics/bridge-limits.png}
|
|
1051 |
\end{center}
|
|
1052 |
||
1053 |
\end{frame}
|
|
1054 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1055 |
||
1056 |
||
1057 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1058 |
\begin{frame}[c]
|
|
1059 |
\frametitle{Compilers \& Boeings 777}
|
|
1060 |
||
1061 |
First flight in 1994. They want to achieve triple redundancy in hardware |
|
1062 |
faults.\bigskip |
|
1063 |
||
1064 |
They compile 1 Ada program to\medskip |
|
1065 |
||
1066 |
\begin{itemize}
|
|
1067 |
\item Intel 80486 |
|
1068 |
\item Motorola 68040 (old Macintosh's) |
|
1069 |
\item AMD 29050 (RISC chips used often in laser printers) |
|
1070 |
\end{itemize}\medskip
|
|
1071 |
||
1072 |
using 3 independent compilers.\bigskip\pause |
|
1073 |
||
1074 |
\small Airbus uses C and static analysers. Recently started using CompCert. |
|
1075 |
||
1076 |
\end{frame}
|
|
1077 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1078 |
||
1079 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1080 |
\begin{frame}[c]
|
|
1081 |
\frametitle{Goal}
|
|
1082 |
||
1083 |
Remember the Bridges example? |
|
1084 |
||
1085 |
\begin{itemize}
|
|
1086 |
\item Can we look at our programs and somehow ensure |
|
1087 |
they are bug free/correct?\pause\bigskip |
|
1088 |
||
1089 |
\item Very hard: Anything interesting about programs is equivalent |
|
1090 |
to the Halting Problem, which is undecidable.\pause\bigskip |
|
1091 |
||
1092 |
\item \alert{Solution:} We avoid this ``minor'' obstacle by
|
|
1093 |
being as close as possible of deciding the halting |
|
1094 |
problem, without actually deciding the halting problem. |
|
1095 |
\small$\quad\Rightarrow$ yes, no, don't know (static analysis) |
|
1096 |
\end{itemize}
|
|
1097 |
||
1098 |
\end{frame}
|
|
1099 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1100 |
||
1101 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1102 |
\begin{frame}[c]
|
|
1103 |
\frametitle{What is Static Analysis?}
|
|
1104 |
||
1105 |
\begin{center}
|
|
1106 |
\includegraphics[scale=0.4]{../pics/state.png}
|
|
1107 |
\end{center}
|
|
1108 |
||
1109 |
\begin{itemize}
|
|
1110 |
\item depending on some initial input, a program |
|
1111 |
(behaviour) will ``develop'' over time. |
|
1112 |
\end{itemize}
|
|
1113 |
||
1114 |
\end{frame}
|
|
1115 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1116 |
||
1117 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1118 |
\begin{frame}[c]
|
|
1119 |
\frametitle{What is Static Analysis?}
|
|
1120 |
||
1121 |
\begin{center}
|
|
1122 |
\includegraphics[scale=0.4]{../pics/state2.png}
|
|
1123 |
\end{center}
|
|
1124 |
||
1125 |
\end{frame}
|
|
1126 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1127 |
||
1128 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1129 |
\begin{frame}[c]
|
|
1130 |
\frametitle{What is Static Analysis?}
|
|
1131 |
||
1132 |
\begin{center}
|
|
1133 |
\includegraphics[scale=0.4]{../pics/state3.jpg}
|
|
1134 |
\end{center}
|
|
1135 |
||
1136 |
\end{frame}
|
|
1137 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1138 |
||
1139 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1140 |
\begin{frame}[c]
|
|
1141 |
\frametitle{What is Static Analysis?}
|
|
1142 |
||
1143 |
\begin{center}
|
|
1144 |
\includegraphics[scale=0.4]{../pics/state4.jpg}
|
|
1145 |
\end{center}
|
|
1146 |
||
1147 |
\begin{itemize}
|
|
1148 |
\item to be avoided |
|
1149 |
\end{itemize}
|
|
1150 |
||
1151 |
\end{frame}
|
|
1152 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1153 |
||
1154 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1155 |
\begin{frame}[c]
|
|
1156 |
\frametitle{What is Static Analysis?}
|
|
1157 |
||
1158 |
\begin{center}
|
|
1159 |
\includegraphics[scale=0.4]{../pics/state5.png}
|
|
1160 |
\end{center}
|
|
1161 |
||
1162 |
\begin{itemize}
|
|
1163 |
\item this needs more work |
|
1164 |
\end{itemize}
|
|
1165 |
||
1166 |
\end{frame}
|
|
1167 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1168 |
||
1169 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1170 |
\begin{frame}[c]
|
|
1171 |
\frametitle{What is Static Analysis?}
|
|
1172 |
||
1173 |
\begin{center}
|
|
1174 |
\includegraphics[scale=0.4]{../pics/state6.png}
|
|
1175 |
\end{center}
|
|
1176 |
||
1177 |
\end{frame}
|
|
1178 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1179 |
||
1180 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1181 |
\begin{frame}[c,fragile]
|
|
1182 |
\frametitle{\Large\begin{tabular}{c}Concrete Example:\\[-1mm]
|
|
1183 |
Are Vars Definitely Initialised?\end{tabular}}
|
|
1184 |
||
1185 |
Assuming \texttt{x} is initialised, what about \texttt{y}?\bigskip
|
|
1186 |
||
1187 |
Prog.~1:\\ |
|
1188 |
\begin{lstlisting}[numbers=none,
|
|
1189 |
basicstyle=\ttfamily, |
|
1190 |
language=While,xleftmargin=3mm] |
|
1191 |
if x < 1 then y := x else y := x + 1; |
|
1192 |
y := y + 1 |
|
1193 |
\end{lstlisting}\medskip
|
|
1194 |
||
1195 |
Prog.~2:\\ |
|
1196 |
\begin{lstlisting}[numbers=none,
|
|
1197 |
basicstyle=\ttfamily, |
|
1198 |
language=While,xleftmargin=3mm] |
|
1199 |
if x < x then y := y + 1 else y := x; |
|
1200 |
y := y + 1 |
|
1201 |
\end{lstlisting}
|
|
1202 |
||
1203 |
\end{frame}
|
|
1204 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1205 |
||
1206 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1207 |
\begin{frame}[c,fragile]
|
|
1208 |
\frametitle{\Large\begin{tabular}{c}Concrete Example:\\[-1mm]
|
|
1209 |
Are Vars Definitely Initialised?\end{tabular}}
|
|
1210 |
||
1211 |
What should the rules be for deciding when a |
|
1212 |
variable is initialised?\bigskip\pause |
|
1213 |
||
1214 |
\begin{itemize}
|
|
1215 |
\item variable \texttt{x} is definitely initialized after
|
|
1216 |
\texttt{skip}\\
|
|
1217 |
iff \texttt{x} is definitely initialized before \texttt{skip}.
|
|
1218 |
\end{itemize}
|
|
1219 |
||
1220 |
\end{frame}
|
|
1221 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1222 |
||
1223 |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
|
1224 |
\begin{frame}[c,fragile]
|
|
1225 |
% \frametitle{\Large\begin{tabular}{c}Concrete Example:\\[-1mm]
|
|
1226 |
% Are Vars Definitely Initialised?\end{tabular}}
|
|
1227 |
||
1228 |
$\bl{A}$ is the set of definitely defined variables:
|
|
1229 |
||
1230 |
\begin{center}
|
|
1231 |
\begin{tabular}{c}
|
|
| 612 | 1232 |
\bl{\infer{\mbox{}}{A\triangleright\texttt{skip}\triangleright{}A}}\qquad
|
1233 |
\bl{\infer{vars(a) \subseteq A}{A\triangleright
|
|
1234 |
(\texttt{x\,:=\,a})\triangleright\{x\}\cup A}}
|
|
| 610 | 1235 |
\medskip\\\pause |
1236 |
||
| 612 | 1237 |
\bl{\infer{A_1\triangleright{}s_1\triangleright{}A_2
|
1238 |
\quad A_2\triangleright{}s_2\triangleright{}A_3}
|
|
1239 |
{A_1\triangleright{}(s_1 ; s_2)\triangleright{}A_3}}
|
|
| 610 | 1240 |
\medskip\\\pause |
1241 |
||
| 612 | 1242 |
\bl{\infer{vars(b)\subseteq A\quad A\triangleright{}s_1\triangleright{}A_1
|
1243 |
\quad A\triangleright{}s_2\triangleright{}A_2}
|
|
1244 |
{A\triangleright(\texttt{if}\;b\;\texttt{then}\;s_1\;\texttt{else}\;s_2)\triangleright{}A_1\cap A_2}}
|
|
| 610 | 1245 |
\medskip\\\pause |
1246 |
||
| 612 | 1247 |
\bl{\infer{vars(b)\subseteq A\quad A\triangleright{}s\triangleright{}A'}
|
1248 |
{A\triangleright(\texttt{while}\;b\;\texttt{do}\;s)\triangleright{}A}}\pause
|
|
| 610 | 1249 |
\end{tabular}
|
1250 |
\end{center}
|
|
1251 |
||
1252 |
\hfill we start with $\bl{A = \{\}}$
|
|
1253 |
\end{frame}
|
|
1254 |
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|
1255 |