| author | Christian Urban <christian.urban@kcl.ac.uk> | 
| Mon, 30 Sep 2024 10:47:49 +0100 | |
| changeset 965 | e7dbebf43ac3 | 
| parent 957 | 03c5a8987141 | 
| child 974 | 06148fc63273 | 
| permissions | -rw-r--r-- | 
| 701 | 1 | % !TEX program = xelatex | 
| 744 | 2 | \documentclass[dvipsnames,14pt,t,xelatex,aspectratio=169,xcolor={table}]{beamer}
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changeset | 3 | \usepackage{../slides}
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changeset | 4 | \usepackage{../langs}
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| 609 | 5 | \usepackage{../data}
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| 871 | 6 | \usepackage{../graphicss}
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changeset | 7 | \usepackage{../grammar}
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| 957 | 8 | %\usepackage{soul}
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| 9 | %\usepackage{mathpartir}
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| 701 | 10 | \usetikzlibrary{shapes,arrows,shadows}
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changeset | 11 | |
| 957 | 12 | \usepackage[most]{tcolorbox}
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| 13 | ||
| 14 | \newtcbox{\hl}[1][]{%
 | |
| 15 | size=fbox, | |
| 16 | tcbox raise base, nobeforeafter, | |
| 17 | enhanced, colframe=gray, | |
| 18 | colback=gray!30, boxrule=1pt, | |
| 19 | fontupper=\ttfamily, | |
| 20 | #1} | |
| 21 | ||
| 22 | ||
| 23 | ||
| 24 | ||
| 609 | 25 | % beamer stuff | 
| 459 | 26 | \renewcommand{\slidecaption}{CFL 09, King's College London}
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| 609 | 27 | \newcommand{\bl}[1]{\textcolor{blue}{#1}}       
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| 28 | ||
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changeset | 29 | |
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changeset | 30 | \begin{document}
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| 609 | 31 | |
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changeset | 32 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
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changeset | 33 | \begin{frame}[t]
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changeset | 34 | \frametitle{%
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changeset | 35 |   \begin{tabular}{@ {}c@ {}}
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changeset | 36 | \\[-3mm] | 
| 459 | 37 | \LARGE Compilers and \\[-2mm] | 
| 901 | 38 | \LARGE Formal Languages\\[-3mm] | 
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changeset | 39 |   \end{tabular}}
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changeset | 40 | |
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changeset | 41 | \normalsize | 
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changeset | 42 |   \begin{center}
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changeset | 43 |   \begin{tabular}{ll}
 | 
| 939 | 44 | Email: & christian.urban at kcl.ac.uk\\ | 
| 45 | Office Hour: & Thurdays 15 -- 16\\ | |
| 901 | 46 | Location: & N7.07 (North Wing, Bush House)\\ | 
| 47 | Slides \& Progs: & KEATS\\ | |
| 48 |   Pollev: & \texttt{\alert{https://pollev.com/cfltutoratki576}}\\  
 | |
| 538 | 49 |   \end{tabular}
 | 
| 50 |   \end{center}
 | |
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changeset | 51 | |
| 744 | 52 |   \begin{center}
 | 
| 53 |     \begin{tikzpicture}
 | |
| 54 | \node[drop shadow,fill=white,inner sep=0pt] | |
| 55 |       {\footnotesize\rowcolors{1}{capri!10}{white}
 | |
| 56 |         \begin{tabular}{|p{4.8cm}|p{4.8cm}|}\hline
 | |
| 57 | 1 Introduction, Languages & 6 While-Language \\ | |
| 58 | 2 Regular Expressions, Derivatives & 7 Compilation, JVM \\ | |
| 59 | 3 Automata, Regular Languages & 8 Compiling Functional Languages \\ | |
| 60 |           4 Lexing, Tokenising               & \cellcolor{blue!50} 9 Optimisations \\
 | |
| 61 | 5 Grammars, Parsing & 10 LLVM \\ \hline | |
| 62 |         \end{tabular}%
 | |
| 63 | }; | |
| 64 |     \end{tikzpicture}
 | |
| 65 |   \end{center}
 | |
| 609 | 66 | \end{frame}
 | 
| 67 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 68 | ||
| 701 | 69 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 70 | \begin{frame}[c,fragile]
 | |
| 702 | 71 | \frametitle{The Fun Language}
 | 
| 609 | 72 | |
| 701 | 73 | \footnotesize | 
| 74 | \begin{textblock}{13}(0.9,3)
 | |
| 864 | 75 | \begin{lstlisting}[numbers=none]
 | 
| 701 | 76 | def fib(n) = if n == 0 then 0 | 
| 77 | else if n == 1 then 1 | |
| 78 | else fib(n - 1) + fib(n - 2); | |
| 609 | 79 | |
| 701 | 80 | def fact(n) = if n == 0 then 1 else n * fact(n - 1); | 
| 609 | 81 | |
| 701 | 82 | def ack(m, n) = if m == 0 then n + 1 | 
| 83 | else if n == 0 then ack(m - 1, 1) | |
| 84 | else ack(m - 1, ack(m, n - 1)); | |
| 85 | ||
| 86 | def gcd(a, b) = if b == 0 then a else gcd(b, a % b); | |
| 87 | \end{lstlisting}
 | |
| 88 | \end{textblock}
 | |
| 609 | 89 | |
| 90 | \end{frame}
 | |
| 91 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 901 | 92 | |
| 853 | 93 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 957 | 94 | %\begin{frame}[c, fragile]
 | 
| 95 | %\frametitle{Stack Estimation}
 | |
| 96 | %\small | |
| 97 | %\mbox{}\\[-15mm]%
 | |
| 98 | % | |
| 99 | %\bl{\begin{center}
 | |
| 100 | %\begin{tabular}{@{\hspace{-4mm}}l@{\hspace{2mm}}c@{\hspace{2mm}}l@{}}
 | |
| 101 | %$\textit{estimate}(n)$ & $\dn$ & $1$\\
 | |
| 102 | %$\textit{estimate}(x)$ & $\dn$ & $1$\\
 | |
| 103 | %$\textit{estimate}(a_1\;aop\;a_2)$ & $\dn$ &
 | |
| 104 | %$\textit{estimate}(a_1) + \textit{estimate}(a_2)$\\
 | |
| 105 | %$\textit{estimate}(\pcode{if}\;b\;\pcode{then}\;e_1\;\pcode{else}\;e_2)$ & $\dn$ & 
 | |
| 106 | %$\textit{estimate}(b) +$\\ 
 | |
| 107 | %& & $\quad max(\textit{estimate}(e_1), \textit{estimate}(e_2))$\\
 | |
| 108 | %$\textit{estimate}(\pcode{write}(e))$ & $\dn$ & 
 | |
| 109 | %$\textit{estimate}(e) + 1$\\
 | |
| 110 | %$\textit{estimate}(e_1 ; e_2)$ & $\dn$ & 
 | |
| 111 | %$max(\textit{estimate}(e_1), \textit{estimate}(e_2))$\\
 | |
| 112 | %$\textit{estimate}(f(e_1, ..., e_n))$ & $\dn$ & 
 | |
| 113 | %$\sum_{i = 1..n}\;estimate(e_i)$\medskip\\
 | |
| 114 | %$\textit{estimate}(a_1\;bop\;a_2)$ & $\dn$ &
 | |
| 115 | %$\textit{estimate}(a_1) + \textit{estimate}(a_2)$\\
 | |
| 116 | %\end{tabular}
 | |
| 117 | %\end{center}}
 | |
| 118 | ||
| 119 | %\end{frame}
 | |
| 120 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 121 | ||
| 122 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 123 | ||
| 124 | ||
| 125 | \begin{frame}[c,fragile]
 | |
| 126 | \frametitle{\mbox{}\hspace{5cm}Factorial}
 | |
| 901 | 127 | |
| 957 | 128 | \begin{textblock}{7}(0,1.6)\footnotesize
 | 
| 129 | \begin{minipage}{6cm}
 | |
| 130 | \begin{lstlisting}[language=JVMIS,basicstyle=\ttfamily, numbers=none]
 | |
| 131 | .method public static fact(I)I | |
| 132 | .limit locals 1 | |
| 133 | .limit stack 6 | |
| 134 | iload 0 | |
| 135 | ldc 0 | |
| 136 | if_icmpne If_else_0 | |
| 137 | ldc 1 | |
| 138 | goto If_end_1 | |
| 139 | If_else_0: | |
| 140 | iload 0 | |
| 141 | iload 0 | |
| 142 | ldc 1 | |
| 143 | isub | |
| 144 | invokestatic fact/fact/fact(I)I | |
| 145 | imul | |
| 146 | If_end_1: | |
| 147 | ireturn | |
| 148 | .end method | |
| 149 | \end{lstlisting}
 | |
| 150 | \end{minipage}
 | |
| 151 | \end{textblock}
 | |
| 152 | ||
| 153 | \begin{textblock}{7}(6,7)
 | |
| 154 | \begin{bubble}[7cm]\small
 | |
| 155 | \begin{lstlisting}[language=Lisp,
 | |
| 156 | basicstyle=\ttfamily, | |
| 157 | numbers=none, | |
| 158 |                    xleftmargin=1mm,linebackgroundcolor=\color{cream}]
 | |
| 159 | def fact(n) = | |
| 160 | if n == 0 then 1 | |
| 161 | else n * fact(n - 1) | |
| 162 | \end{lstlisting}
 | |
| 163 | \end{bubble}
 | |
| 164 | \end{textblock}
 | |
| 901 | 165 | |
| 166 | \end{frame}
 | |
| 957 | 167 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 901 | 168 | |
| 169 | ||
| 170 | ||
| 171 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 172 | ||
| 173 | ||
| 853 | 174 | \begin{frame}[c,fragile]
 | 
| 175 | \frametitle{\mbox{}\hspace{5cm}Factorial}
 | |
| 176 | ||
| 177 | \begin{textblock}{7}(0,1.0)\footnotesize
 | |
| 178 | \begin{minipage}{6cm}
 | |
| 179 | \begin{lstlisting}[language=JVMIS,basicstyle=\ttfamily, numbers=none]
 | |
| 180 | .method public static facT(II)I | |
| 181 | .limit locals 2 | |
| 182 | .limit stack 6 | |
| 183 | iload 0 | |
| 184 | ldc 0 | |
| 185 | if_icmpne If_else_2 | |
| 186 | iload 1 | |
| 187 | goto If_end_3 | |
| 188 | If_else_2: | |
| 189 | iload 0 | |
| 190 | ldc 1 | |
| 191 | isub | |
| 192 | iload 0 | |
| 193 | iload 1 | |
| 194 | imul | |
| 195 | invokestatic fact/fact/facT(II)I | |
| 196 | If_end_3: | |
| 197 | ireturn | |
| 198 | .end method | |
| 199 | \end{lstlisting}
 | |
| 200 | \end{minipage}
 | |
| 201 | \end{textblock}
 | |
| 202 | ||
| 203 | \begin{textblock}{7}(6,7)
 | |
| 204 | \begin{bubble}[7cm]\small
 | |
| 205 | \begin{lstlisting}[language=Lisp,
 | |
| 206 | basicstyle=\ttfamily, | |
| 207 | numbers=none, | |
| 208 |                    xleftmargin=1mm,linebackgroundcolor=\color{cream}]
 | |
| 209 | def facT(n, acc) = | |
| 210 | if n == 0 then acc | |
| 957 | 211 | else facT(n - 1, n * acc) | 
| 853 | 212 | \end{lstlisting}
 | 
| 213 | \end{bubble}
 | |
| 214 | \end{textblock}
 | |
| 215 | ||
| 216 | \end{frame}
 | |
| 217 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 218 | ||
| 219 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 220 | \begin{frame}[fragile]
 | |
| 221 | ||
| 957 | 222 | \begin{textblock}{7}(1,-0.38)\footnotesize
 | 
| 853 | 223 | \begin{minipage}{6cm}
 | 
| 224 | \begin{lstlisting}[language=JVMIS,basicstyle=\ttfamily, numbers=none, escapeinside={(*@}{@*)}]
 | |
| 225 | .method public static facT(II)I | |
| 226 | .limit locals 2 | |
| 227 | .limit stack 6 | |
| 228 | (*@\hl{facT\_Start:} @*)
 | |
| 229 | iload 0 | |
| 230 | ldc 0 | |
| 231 | if_icmpne If_else_2 | |
| 232 | iload 1 | |
| 233 | goto If_end_3 | |
| 234 | If_else_2: | |
| 235 | iload 0 | |
| 236 | ldc 1 | |
| 237 | isub | |
| 238 | iload 0 | |
| 239 | iload 1 | |
| 240 | imul | |
| 241 |   (*@\hl{istore 1} @*)
 | |
| 242 |   (*@\hl{istore 0} @*)
 | |
| 243 |   (*@\hl{goto facT\_Start} @*)
 | |
| 244 | If_end_3: | |
| 245 | ireturn | |
| 246 | .end method | |
| 247 | \end{lstlisting}
 | |
| 248 | \end{minipage}
 | |
| 249 | \end{textblock}
 | |
| 250 | ||
| 251 | \begin{textblock}{7}(6,7)
 | |
| 252 | \begin{bubble}[7cm]\small
 | |
| 253 | \begin{lstlisting}[language=Lisp,
 | |
| 254 | basicstyle=\ttfamily, | |
| 255 | numbers=none, | |
| 256 |                    xleftmargin=1mm,linebackgroundcolor=\color{cream}]
 | |
| 257 | def facT(n, acc) = | |
| 258 | if n == 0 then acc | |
| 259 | else facT(n - 1, n * acc); | |
| 260 | \end{lstlisting}
 | |
| 261 | \end{bubble}
 | |
| 262 | \end{textblock}
 | |
| 263 | ||
| 264 | \end{frame}
 | |
| 265 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 266 | ||
| 267 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 268 | \begin{frame}[t, fragile]
 | |
| 269 | \frametitle{Tail Recursion}
 | |
| 270 | ||
| 271 | A call to \texttt{f(args)} is usually compiled as\medskip
 | |
| 272 | ||
| 273 | {\small\begin{lstlisting}[basicstyle=\ttfamily, numbers=none]
 | |
| 274 | args onto stack | |
| 275 | invokestatic .../f | |
| 276 | \end{lstlisting}}\pause
 | |
| 277 | ||
| 278 | ||
| 279 | A call is in tail position provided:\medskip | |
| 280 | ||
| 281 | {\small\begin{itemize}
 | |
| 282 | \item \texttt{if Bexp then \hl{Exp} else \hl{Exp}}
 | |
| 283 | \item \texttt{Exp ; \hl{Exp}}
 | |
| 284 | \item \texttt{Exp  op Exp}
 | |
| 285 | \end{itemize}}\medskip
 | |
| 286 | ||
| 287 | then a call \texttt{f(args)} can be compiled as\medskip\small
 | |
| 288 | ||
| 289 | \begin{lstlisting}[numbers=none]
 | |
| 290 | prepare environment | |
| 291 | jump to start of function | |
| 292 | \end{lstlisting}
 | |
| 293 | ||
| 294 | \end{frame}
 | |
| 295 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 296 | ||
| 297 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 298 | \begin{frame}[c, fragile]
 | |
| 299 | \frametitle{Tail Recursive Call}
 | |
| 300 | \footnotesize | |
| 301 | ||
| 302 | \begin{textblock}{13}(-0.3,3)
 | |
| 303 | \begin{lstlisting}[language=Scala, numbers=none]
 | |
| 304 | def compile_expT(a: Exp, env: Mem, name: String): Instrs = | |
| 305 | ... | |
| 306 | case Call(n, args) => if (name == n) | |
| 307 |   {
 | |
| 308 | val stores = | |
| 309 |       args.zipWithIndex.map { case (x, y) => i"istore $y" } 
 | |
| 310 | ||
| 311 | args.map(a => compile_expT(a, env, "")).mkString ++ | |
| 312 | stores.reverse.mkString ++ | |
| 313 |     i"goto ${n}_Start" 
 | |
| 314 |   } else {
 | |
| 315 | val is = "I" * args.length | |
| 316 | args.map(a => compile_expT(a, env, "")).mkString ++ | |
| 317 |     i"invokestatic XXX/XXX/${n}(${is})I"
 | |
| 318 | } | |
| 319 | \end{lstlisting}
 | |
| 320 | \end{textblock}
 | |
| 321 | ||
| 322 | \end{frame}
 | |
| 323 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 609 | 324 | |
| 325 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 957 | 326 | \begin{frame}[c]
 | 
| 327 | \frametitle{???}
 | |
| 328 | ||
| 329 | \small | |
| 330 | \begin{tabular}{cc}
 | |
| 331 |   \includegraphics[scale=0.2]{basic-code.jpg} &
 | |
| 332 |   \includegraphics[scale=0.2]{machine-code.jpg}                                
 | |
| 333 | \end{tabular}
 | |
| 334 | ||
| 335 | ||
| 336 | \end{frame}
 | |
| 337 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 338 | ||
| 339 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 340 | \begin{frame}[t]
 | |
| 341 | \frametitle{Opcodes}
 | |
| 342 | ||
| 343 | \small | |
| 344 | \begin{tabular}{cc}
 | |
| 345 |   \includegraphics[scale=0.3]{machine-code-large.png}      
 | |
| 346 | \end{tabular}
 | |
| 347 | ||
| 348 | ||
| 349 | \end{frame}
 | |
| 350 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 351 | ||
| 352 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 353 | \begin{frame}<1-2>[t]
 | |
| 354 | ||
| 355 | \end{frame}
 | |
| 356 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 357 | ||
| 358 | ||
| 359 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 609 | 360 | \begin{frame}[c,fragile]
 | 
| 901 | 361 | \frametitle{Peephole Optimisations}
 | 
| 609 | 362 | |
| 901 | 363 | \begin{center}
 | 
| 364 | \begin{tabular}{ll}
 | |
| 365 |   \texttt{ldc}:  & \texttt{iconst\_0} \ldots \texttt{iconst\_5}\\
 | |
| 366 |                  & \texttt{bipush} $n$ where $-128 < n <= 128$\bigskip\\  
 | |
| 367 |   \texttt{iload}: &  \texttt{iload\_0} \ldots \texttt{iload\_3}\bigskip\\
 | |
| 368 |   \texttt{istore}: &  \texttt{istore\_0} \ldots \texttt{istore\_3}\\
 | |
| 369 | \end{tabular}
 | |
| 370 | \end{center}  
 | |
| 701 | 371 | |
| 372 | \end{frame}
 | |
| 373 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 374 | ||
| 375 | ||
| 376 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 901 | 377 | %\begin{frame}[c,fragile]
 | 
| 378 | %\frametitle{Factorial Funct.~on the JVM}
 | |
| 379 | % | |
| 380 | %\begin{textblock}{7}(1,1.8)\footnotesize
 | |
| 381 | %\begin{minipage}{6cm}
 | |
| 382 | %\begin{lstlisting}[language=JVMIS,basicstyle=\ttfamily, numbers=none]
 | |
| 383 | %.method public static facT(II)I | |
| 384 | %.limit locals 2 | |
| 385 | %.limit stack 6 | |
| 386 | % iload 0 | |
| 387 | % ldc 0 | |
| 388 | % if_icmpne If_else_2 | |
| 389 | % iload 1 | |
| 390 | % goto If_end_3 | |
| 391 | %If_else_2: | |
| 392 | % iload 0 | |
| 393 | % ldc 1 | |
| 394 | % isub | |
| 395 | % iload 0 | |
| 396 | % iload 1 | |
| 397 | % imul | |
| 398 | % invokestatic fact/fact/facT(II)I | |
| 399 | %If_end_3: | |
| 400 | % ireturn | |
| 401 | %.end method | |
| 402 | %\end{lstlisting}
 | |
| 403 | %\end{minipage}
 | |
| 404 | %\end{textblock}
 | |
| 405 | % | |
| 406 | %\begin{textblock}{7}(6,7)
 | |
| 407 | %\begin{bubble}[7cm]\small
 | |
| 408 | %\begin{lstlisting}[language=Lisp,
 | |
| 409 | % basicstyle=\ttfamily, | |
| 410 | % numbers=none, | |
| 411 | %                   xleftmargin=1mm,linebackgroundcolor=\color{cream}]
 | |
| 412 | %def facT(n, acc) = | |
| 413 | % if n == 0 then acc | |
| 414 | % else facT(n - 1, n * acc); | |
| 415 | %\end{lstlisting}
 | |
| 416 | %\end{bubble}
 | |
| 417 | %\end{textblock}
 | |
| 418 | % | |
| 419 | %\end{frame}
 | |
| 420 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 421 | ||
| 422 | ||
| 423 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 701 | 424 | \begin{frame}[fragile,c]
 | 
| 425 | \frametitle{LLVM}
 | |
| 609 | 426 | |
| 427 | \begin{itemize}
 | |
| 701 | 428 | \item Chris Lattner, Vikram Adve (started in 2000) | 
| 429 | \item Apple hired Lattner in 2006 | |
| 430 | \item modular architecture, LLVM-IR | |
| 431 |   \item \texttt{lli} and \texttt{llc} 
 | |
| 432 | \end{itemize}
 | |
| 609 | 433 | |
| 434 | \end{frame}
 | |
| 701 | 435 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 436 | ||
| 437 | ||
| 438 | ||
| 439 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 440 | \tikzstyle{sensor}=[draw, fill=blue!20, text width=3.8em, line width=1mm,
 | |
| 441 | text centered, minimum height=2em,drop shadow] | |
| 442 | \tikzstyle{ann} = [above, text width=4em, text centered]
 | |
| 443 | \tikzstyle{sc} = [sensor, text width=7em, fill=red!20, 
 | |
| 444 | minimum height=6em, rounded corners, drop shadow,line width=1mm] | |
| 445 | ||
| 446 | \begin{frame}[fragile,c]
 | |
| 447 | \frametitle{LLVM: Overview}
 | |
| 448 | ||
| 449 | \begin{tikzpicture}
 | |
| 450 | % Validation Layer is the same except that there are a set of nodes and links which are added | |
| 451 | ||
| 452 |     \path (0,0) node (IR) [sc] {\textbf{LLVM-IR}\\ Optimisations};
 | |
| 453 |     \path (IR.west)+(-2.2,1.7) node (sou1) [sensor] {C++};
 | |
| 454 |     \path (IR.west)+(-2.2,0.5) node (sou2)[sensor] {C};
 | |
| 455 |     \path (IR.west)+(-2.2,-1.0) node (dots)[ann] {$\vdots$}; 
 | |
| 456 |     \path (IR.west)+(-2.2,-1.8) node (sou3)[sensor] {Haskell};    
 | |
| 457 | ||
| 458 |     \path [draw,->,line width=1mm] (sou1.east) -- node [above] {} (IR.160);
 | |
| 459 |     \path [draw,->,line width=1mm] (sou2.east) -- node [above] {} (IR.180);
 | |
| 460 |     \path [draw,->,line width=1mm] (sou3.east) -- node [above] {} (IR.200);
 | |
| 461 | ||
| 462 |     \path (IR.east)+(2.2,2.0)  node (tar1)[sensor] {x86};
 | |
| 463 |     \path (IR.east)+(2.2,0.8)  node (tar2)[sensor] {ARM};
 | |
| 464 |     \path (IR.east)+(2.2,-0.4) node (tar3)[sensor] {MIPS}; 
 | |
| 465 |     \path (IR.east)+(2.2,-1.6) node (tar4)[sensor] {RISC}; 
 | |
| 466 |     \path (IR.east)+(2.2,-2.8) node (tar5)[sensor] {Power PC};
 | |
| 467 |     \path (IR.east)+(2.2,-4.2) node (dots2)[ann] {$\vdots$};
 | |
| 468 | ||
| 469 |     \path [draw,<-,line width=1mm] (tar1.west) -- node [above] {} (IR.10);
 | |
| 470 |     \path [draw,<-,line width=1mm] (tar2.west) -- node [above] {} (IR.5);
 | |
| 471 |     \path [draw,<-,line width=1mm] (tar3.west) -- node [above] {} (IR.0);
 | |
| 472 |     \path [draw,<-,line width=1mm] (tar4.west) -- node [above] {} (IR.-5);
 | |
| 473 |     \path [draw,<-,line width=1mm] (tar5.west) -- node [above] {} (IR.-10);
 | |
| 474 | ||
| 475 | \end{tikzpicture}
 | |
| 476 | \end{frame}
 | |
| 477 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 478 | ||
| 609 | 479 | |
| 480 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 701 | 481 | \begin{frame}[fragile,t]
 | 
| 482 | \frametitle{LLVM-IR}
 | |
| 483 | \small | |
| 484 | ||
| 485 | \begin{textblock}{7.7}(8,11.4)
 | |
| 486 | \begin{bubble}[5cm]\small
 | |
| 487 | \begin{lstlisting}[language=Lisp,
 | |
| 488 | numbers=none, | |
| 489 |                    xleftmargin=1mm,linebackgroundcolor=\color{cream}]
 | |
| 490 | def fact(n) = | |
| 491 | if n == 0 then 1 | |
| 492 | else n * fact(n - 1) | |
| 493 | \end{lstlisting}
 | |
| 494 | \end{bubble}
 | |
| 495 | \end{textblock}
 | |
| 310 
d384fe01d0e8
updated
 Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 
309diff
changeset | 496 | |
| 701 | 497 | \begin{lstlisting}[language=LLVM,xleftmargin=-7mm]
 | 
| 498 | define i32 @fact (i32 %n) {
 | |
| 499 | %tmp_19 = icmp eq i32 %n, 0 | |
| 500 | br i1 %tmp_19, label %if_br_23, label %else_br_24 | |
| 501 | ||
| 502 | if_br_23: | |
| 503 | ret i32 1 | |
| 504 | ||
| 505 | else_br_24: | |
| 506 | %tmp_21 = sub i32 %n, 1 | |
| 507 | %tmp_22 = call i32 @fact (i32 %tmp_21) | |
| 508 | %tmp_20 = mul i32 %n, %tmp_22 | |
| 509 | ret i32 %tmp_20 | |
| 510 | } | |
| 511 | \end{lstlisting}
 | |
| 609 | 512 | |
| 513 | \end{frame}
 | |
| 701 | 514 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 515 | ||
| 516 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 517 | \begin{frame}[fragile,c]
 | |
| 518 | \frametitle{LLVM Types}
 | |
| 519 | ||
| 520 | \tt | |
| 521 | \begin{center}
 | |
| 522 | \begin{tabular}{ll}
 | |
| 523 | boolean & i1 \\ | |
| 524 | byte & i8 \\ | |
| 525 | short & i16\\ | |
| 526 | char & i16\\ | |
| 527 | integer & i32\\ | |
| 528 | long & i64\\ | |
| 529 | float & float\\ | |
| 530 | double & double\\ | |
| 531 | *\_ & pointer to \\ | |
| 532 | **\_ & pointer to a pointer to\\ | |
| 533 | \mbox{}[\_]    & arrays of\\
 | |
| 534 | \end{tabular}
 | |
| 535 | \end{center}
 | |
| 536 | ||
| 537 | \end{frame}
 | |
| 538 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 539 | ||
| 540 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 541 | \begin{frame}[fragile,c]
 | |
| 702 | 542 | \frametitle{LLVM-IR Instructions}
 | 
| 701 | 543 | \small | 
| 544 | ||
| 702 | 545 | \begin{lstlisting}[language=LLVM,xleftmargin=0mm]
 | 
| 701 | 546 | br i1 %var, label %if_br, label %else_br | 
| 547 | ||
| 548 | icmp eq i32 %x, %y ; for equal | |
| 549 | icmp sle i32 %x, %y ; signed less or equal | |
| 550 | icmp slt i32 %x, %y ; signed less than | |
| 551 | icmp ult i32 %x, %y ; unsigned less than | |
| 552 | ||
| 553 | %var = call i32 @foo(...args...) | |
| 554 | \end{lstlisting}
 | |
| 555 | ||
| 556 | \end{frame}
 | |
| 557 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 558 | ||
| 559 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 560 | \begin{frame}[fragile,c]
 | |
| 561 | \frametitle{SSA Format}
 | |
| 562 | ||
| 563 | \bl{$(1 + a) + (3 + (b * 5))$}\bigskip\bigskip
 | |
| 564 | ||
| 565 | \begin{lstlisting}[language=LLVM]
 | |
| 702 | 566 | tmp0 = add 1 a | 
| 567 | tmp1 = mul b 5 | |
| 568 | tmp2 = add 3 tmp1 | |
| 569 | tmp3 = add tmp0 tmp2 | |
| 570 | \end{lstlisting}\bigskip\bigskip
 | |
| 571 | ||
| 572 | \hfill Static Single Assignment | |
| 701 | 573 | |
| 574 | \end{frame}
 | |
| 575 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 609 | 576 | |
| 577 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 701 | 578 | \begin{frame}[fragile,c]
 | 
| 579 | \frametitle{Abstract Syntax Trees}
 | |
| 580 | \footnotesize | |
| 581 | ||
| 582 | \begin{lstlisting}[language=Scala,numbers=none,xleftmargin=-3mm]
 | |
| 583 | // Fun language (expressions) | |
| 584 | abstract class Exp | |
| 585 | abstract class BExp | |
| 586 | ||
| 587 | case class Call(name: String, args: List[Exp]) extends Exp | |
| 588 | case class If(a: BExp, e1: Exp, e2: Exp) extends Exp | |
| 589 | case class Write(e: Exp) extends Exp | |
| 590 | case class Var(s: String) extends Exp | |
| 591 | case class Num(i: Int) extends Exp | |
| 592 | case class Aop(o: String, a1: Exp, a2: Exp) extends Exp | |
| 593 | case class Sequence(e1: Exp, e2: Exp) extends Exp | |
| 594 | case class Bop(o: String, a1: Exp, a2: Exp) extends BExp | |
| 595 | \end{lstlisting}
 | |
| 609 | 596 | |
| 701 | 597 | \end{frame}
 | 
| 598 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 599 | ||
| 600 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 601 | \begin{frame}[fragile,c]
 | |
| 602 | \frametitle{K-(Intermediate)Language}
 | |
| 603 | \footnotesize | |
| 609 | 604 | |
| 701 | 605 | \begin{lstlisting}[language=Scala,numbers=none,xleftmargin=-3mm]
 | 
| 606 | abstract class KExp | |
| 607 | abstract class KVal | |
| 608 | ||
| 702 | 609 | // K-Values | 
| 701 | 610 | case class KVar(s: String) extends KVal | 
| 611 | case class KNum(i: Int) extends KVal | |
| 612 | case class Kop(o: String, v1: KVal, v2: KVal) extends KVal | |
| 613 | case class KCall(o: String, vrs: List[KVal]) extends KVal | |
| 614 | case class KWrite(v: KVal) extends KVal | |
| 615 | ||
| 702 | 616 | // K-Expressions | 
| 701 | 617 | case class KIf(x1: String, e1: KExp, e2: KExp) extends KExp | 
| 618 | case class KLet(x: String, v: KVal, e: KExp) extends KExp | |
| 619 | case class KReturn(v: KVal) extends KExp | |
| 609 | 620 | \end{lstlisting}
 | 
| 621 | ||
| 701 | 622 | \end{frame}
 | 
| 623 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 624 | ||
| 625 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 626 | \begin{frame}[fragile,c]
 | |
| 819 | 627 | \frametitle{KLet}
 | 
| 628 | ||
| 629 | \begin{lstlisting}[language=LLVM]
 | |
| 630 | tmp0 = add 1 a | |
| 631 | tmp1 = mul b 5 | |
| 632 | tmp2 = add 3 tmp1 | |
| 633 | tmp3 = add tmp0 tmp2 | |
| 634 | \end{lstlisting}
 | |
| 635 | ||
| 636 | \begin{lstlisting}[language=LLVMIR]
 | |
| 637 | KLet tmp0 , add 1 a in | |
| 638 | KLet tmp1 , mul b 5 in | |
| 639 | KLet tmp2 , add 3 tmp1 in | |
| 640 | KLet tmp3 , add tmp0 tmp2 in | |
| 641 | ... | |
| 642 | \end{lstlisting}
 | |
| 643 | ||
| 644 | \begin{lstlisting}[language=Scala,numbers=none]
 | |
| 645 | case class KLet(x: String, e1: KVal, e2: KExp) | |
| 646 | \end{lstlisting}
 | |
| 647 | ||
| 648 | \end{frame}
 | |
| 649 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 650 | ||
| 651 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 652 | \begin{frame}[fragile,c]
 | |
| 653 | \frametitle{KLet}
 | |
| 654 | ||
| 655 | \begin{lstlisting}[language=LLVM]
 | |
| 656 | tmp0 = add 1 a | |
| 657 | tmp1 = mul b 5 | |
| 658 | tmp2 = add 3 tmp1 | |
| 659 | tmp3 = add tmp0 tmp2 | |
| 660 | \end{lstlisting}
 | |
| 661 | ||
| 662 | \begin{lstlisting}[language=LLVMIR]
 | |
| 663 | let tmp0 = add 1 a in | |
| 664 | let tmp1 = mul b 5 in | |
| 665 | let tmp2 = add 3 tmp1 in | |
| 666 | let tmp3 = add tmp0 tmp2 in | |
| 667 | ... | |
| 668 | \end{lstlisting}
 | |
| 669 | ||
| 670 | \begin{lstlisting}[language=Scala,numbers=none]
 | |
| 671 | case class KLet(x: String, e1: KVal, e2: KExp) | |
| 672 | \end{lstlisting}
 | |
| 673 | ||
| 674 | \end{frame}
 | |
| 675 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 676 | ||
| 677 | ||
| 678 | ||
| 679 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 680 | \begin{frame}[fragile,c]
 | |
| 701 | 681 | \frametitle{CPS-Translation}
 | 
| 682 | \small | |
| 683 | ||
| 684 | \begin{lstlisting}[language=Scala,numbers=none]
 | |
| 685 | def CPS(e: Exp)(k: KVal => KExp) : KExp = | |
| 686 |   e match { ... }
 | |
| 687 | \end{lstlisting}
 | |
| 688 | \bigskip\bigskip | |
| 689 | ||
| 702 | 690 | the continuation \texttt{k} can be thought of:\medskip
 | 
| 691 | ||
| 701 | 692 | \small | 
| 693 | \begin{lstlisting}[language=LLVMIR,numbers=none,xleftmargin=30mm,escapeinside={(*@}{@*)}]
 | |
| 694 | let tmp0 = add 1 a in | |
| 695 | let tmp1 = mul (*@$\Box$@*) 5 in | |
| 696 | let tmp2 = add 3 tmp1 in | |
| 697 | let tmp3 = add tmp0 tmp2 in | |
| 698 | KReturn tmp3 | |
| 699 | \end{lstlisting}
 | |
| 609 | 700 | |
| 701 | \end{frame}
 | |
| 701 | 702 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 703 | ||
| 704 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 705 | \begin{frame}[fragile,c]
 | |
| 706 | \frametitle{CPS-Translation}
 | |
| 707 | \small | |
| 708 | ||
| 709 | \begin{lstlisting}[language=Scala,numbers=none]
 | |
| 710 | def CPS(e: Exp)(k: KVal => KExp) : KExp = | |
| 711 |   e match { 
 | |
| 712 | case Var(s) => k(KVar(s)) | |
| 713 | case Num(i) => k(KNum(i)) | |
| 714 | ... | |
| 715 | } | |
| 716 | \end{lstlisting}
 | |
| 717 | \bigskip\bigskip | |
| 718 | ||
| 719 | \small | |
| 720 | \begin{lstlisting}[language=LLVMIR,numbers=none,xleftmargin=30mm,escapeinside={(*@}{@*)}]
 | |
| 721 | let tmp0 = add 1 a in | |
| 722 | let tmp1 = mul (*@$\Box$@*) 5 in | |
| 723 | let tmp2 = add 3 tmp1 in | |
| 724 | let tmp3 = add tmp0 tmp2 in | |
| 725 | KReturn tmp3 | |
| 726 | \end{lstlisting}
 | |
| 727 | ||
| 728 | \end{frame}
 | |
| 729 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 609 | 730 | |
| 731 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 701 | 732 | \begin{frame}[fragile,c]
 | 
| 733 | \frametitle{CPS-Translation}
 | |
| 734 | \small | |
| 609 | 735 | |
| 701 | 736 | \begin{lstlisting}[language=Scala,numbers=none,xleftmargin=-5mm]
 | 
| 737 | def CPS(e: Exp)(k: KVal => KExp) : KExp = e match { 
 | |
| 738 |   case Aop(o, e1, e2) => {
 | |
| 739 |     val z = Fresh("tmp")
 | |
| 740 | CPS(e1)(y1 => | |
| 741 | CPS(e2)(y2 => | |
| 742 | KLet(z, Kop(o, y1, y2), k(KVar(z))))) | |
| 743 | } ... | |
| 744 | } | |
| 609 | 745 | \end{lstlisting}
 | 
| 702 | 746 | \mbox{}\\[-8mm]%
 | 
| 747 | % | |
| 701 | 748 | \begin{lstlisting}[language=LLVMIR,numbers=none,xleftmargin=30mm,escapeinside={(*@}{@*)}]
 | 
| 749 | ... | |
| 750 | let z = op (*@$\Box_{y_1}$@*) (*@$\Box_{y_2}$@*)
 | |
| 751 | let tmp0 = add 1 a in | |
| 702 | 752 | let tmp1 = mul (*@$\Box\!\!\!\!\raisebox{0.6mm}{\alert{\texttt{z}}}$@*) 5 in 
 | 
| 701 | 753 | let tmp2 = add 3 tmp1 in | 
| 754 | let tmp3 = add tmp0 tmp2 in | |
| 755 | KReturn tmp3 | |
| 756 | \end{lstlisting}
 | |
| 609 | 757 | |
| 758 | \end{frame}
 | |
| 701 | 759 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 609 | 760 | |
| 761 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 701 | 762 | \begin{frame}[fragile,c]
 | 
| 763 | \frametitle{CPS-Translation}
 | |
| 764 | \small | |
| 609 | 765 | |
| 701 | 766 | \begin{lstlisting}[language=Scala,numbers=none]
 | 
| 767 | def CPS(e: Exp)(k: KVal => KExp) : KExp = | |
| 768 |   e match { 
 | |
| 769 | case Sequence(e1, e2) => | |
| 770 | CPS(e1)(_ => CPS(e2)(y2 => k(y2))) | |
| 771 | ... | |
| 772 | } | |
| 773 | \end{lstlisting}
 | |
| 702 | 774 | \bigskip | 
| 701 | 775 | |
| 776 | \small | |
| 777 | \begin{lstlisting}[language=LLVMIR,numbers=none,xleftmargin=30mm,escapeinside={(*@}{@*)}]
 | |
| 778 | let tmp0 = add 1 a in | |
| 779 | let tmp1 = mul (*@$\Box$@*) 5 in | |
| 780 | let tmp2 = add 3 tmp1 in | |
| 781 | let tmp3 = add tmp0 tmp2 in | |
| 782 | KReturn tmp3 | |
| 783 | \end{lstlisting}
 | |
| 609 | 784 | |
| 785 | \end{frame}
 | |
| 701 | 786 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 310 
d384fe01d0e8
updated
 Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 
309diff
changeset | 787 | |
| 610 | 788 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 701 | 789 | \begin{frame}[fragile,c]
 | 
| 790 | \frametitle{CPS-Translation}
 | |
| 791 | \small | |
| 792 | ||
| 793 | \begin{lstlisting}[language=Scala,numbers=none,xleftmargin=-3mm]
 | |
| 794 | def CPS(e: Exp)(k: KVal => KExp) : KExp = | |
| 795 |   e match { 
 | |
| 796 | ... | |
| 797 |     case If(Bop(o, b1, b2), e1, e2) => {
 | |
| 798 |       val z = Fresh("tmp")
 | |
| 799 | CPS(b1)(y1 => | |
| 800 | CPS(b2)(y2 => | |
| 801 | KLet(z, Kop(o, y1, y2), | |
| 802 | KIf(z, CPS(e1)(k), CPS(e2)(k))))) | |
| 803 | } | |
| 804 | ... | |
| 805 | } | |
| 806 | \end{lstlisting}
 | |
| 807 | ||
| 808 | \end{frame}
 | |
| 809 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 810 | ||
| 702 | 811 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 812 | \begin{frame}[c,fragile]
 | |
| 813 | \frametitle{The Basic Language, 1980+}
 | |
| 814 | ||
| 815 | \begin{lstlisting}[language={[Visual]Basic},numbers=none]
 | |
| 816 | 5 LET S = 0 | |
| 817 | 10 INPUT V | |
| 818 | 20 PRINT "Input number" | |
| 819 | 30 IF N = 0 THEN GOTO 99 | |
| 820 | 40 FOR I = 1 TO N | |
| 821 | 45 LET S = S + V(I) | |
| 822 | 50 NEXT I | |
| 823 | 60 PRINT S/N | |
| 824 | 70 GOTO 5 | |
| 825 | 99 END | |
| 826 | \end{lstlisting}
 | |
| 827 | ||
| 828 | \hfill ``Spaghetti Code'' | |
| 829 | \end{frame}
 | |
| 830 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 831 | ||
| 832 | ||
| 833 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 834 | \begin{frame}[c,fragile]
 | |
| 835 | \frametitle{Target Specific ASM}
 | |
| 836 | ||
| 837 | \begin{lstlisting}[language={},numbers=none]
 | |
| 838 | llc -march=x86-64 fact.ll | |
| 839 | llc -march=arm fact.ll | |
| 840 | ||
| 841 | ||
| 842 | Intel: xorl %eax, %eax | |
| 843 | ARM: mov pc, lr | |
| 844 | \end{lstlisting}
 | |
| 845 | ||
| 846 | \end{frame}
 | |
| 847 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 701 | 848 | |
| 849 | ||
| 850 | ||
| 851 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 610 | 852 | \begin{frame}[c]
 | 
| 853 | ||
| 854 | \large\bf | |
| 701 | 855 | Using a compiler, \\ | 
| 856 | how can you mount the\\ | |
| 857 | perfect attack against a system? | |
| 610 | 858 | |
| 701 | 859 | \end{frame}
 | 
| 610 | 860 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 861 | ||
| 862 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 863 | \mode<presentation>{
 | |
| 864 | \begin{frame}[c]
 | |
| 865 | ||
| 866 | {\large\bf
 | |
| 867 | What is a \alert{perfect} attack?}\bigskip
 | |
| 868 | ||
| 869 | \begin{enumerate}
 | |
| 870 | \item you can potentially completely take over a target system | |
| 871 | \item your attack is (nearly) undetectable | |
| 872 | \item the victim has (almost) no chance to recover | |
| 873 | \end{enumerate}
 | |
| 874 | ||
| 875 | \end{frame}}
 | |
| 876 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 877 | ||
| 878 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 879 | \mode<presentation>{
 | |
| 880 | \begin{frame}[c]
 | |
| 881 | ||
| 882 | ||
| 883 |   \begin{center}
 | |
| 884 |   \begin{tikzpicture}[scale=1]
 | |
| 885 | ||
| 886 |   \onslide<1->{
 | |
| 887 |   \node (A) at (0,0)  [draw=black, rectangle, very thick, minimum height=18mm, minimum width=17mm] {};
 | |
| 888 |   \node [below right] at (A.north west) {\footnotesize\begin{tabular}{@{}l@{}}
 | |
| 889 |   \only<1,2>{clean}\only<3->{\alert{hacked}}\\compiler\end{tabular}};}
 | |
| 890 | ||
| 891 | ||
| 892 |   \onslide<2->{
 | |
| 893 |   \node (B) at (-2,2)  [draw=black, rectangle, very thick, minimum height=10mm, minimum width=12mm] {};
 | |
| 894 |   \node [below right] at (B.north west) {\footnotesize\begin{tabular}{@{}l@{}}login\\(src)\end{tabular}};
 | |
| 895 | ||
| 896 |   \node (C) at (2,2)  [draw=black, rectangle, very thick, minimum height=10mm, minimum width=12mm] {};
 | |
| 897 |   \node [below right] at (C.north west) {\footnotesize\begin{tabular}{@{}l@{}}login\\(bin)\end{tabular}};
 | |
| 898 | ||
| 899 | \draw[->, line width=2mm] (B) -- (C); | |
| 900 | } | |
| 901 | ||
| 902 |  \onslide<3->{\node [above left=-1.5mm] at (C.south east) {\footnotesize \alert{$\blacksquare$}};}
 | |
| 903 | ||
| 904 |   \end{tikzpicture}
 | |
| 905 |   \end{center}
 | |
| 906 | ||
| 907 | \end{frame}}
 | |
| 908 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 909 | ||
| 910 | ||
| 911 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 912 | \mode<presentation>{
 | |
| 913 | \begin{frame}[c]
 | |
| 914 | ||
| 915 |   \begin{center}
 | |
| 916 |   \begin{tikzpicture}[scale=1]
 | |
| 917 | ||
| 918 |   \onslide<1->{
 | |
| 919 |   \node (A) at (0,0)  [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
 | |
| 920 |   \node [below right] at (A.north west) {\small V0.01};
 | |
| 921 |   \node [below right] (A1) at (A.south west) {\small Scala};
 | |
| 922 |   \node [below right] (A1) at (A1.south west) {\small\textcolor{gray}{host language}};
 | |
| 923 |   \node [above right] at (A.north west) {my compiler (src)};}
 | |
| 924 | ||
| 925 |   \onslide<2->{
 | |
| 926 |   \node (B) at (1.8,0)  [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
 | |
| 927 |   \node [below right] at (B.north west) {\small V0.02};
 | |
| 928 |   \node [below right] at (B.south west) {\small Scala};
 | |
| 929 |   \node at (3,0) {\ldots};
 | |
| 930 | ||
| 931 |   \node (C) at (5,0)  [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
 | |
| 932 |   \node [below right] at (C.north west) {\small V1.00};
 | |
| 933 |   \node [below right] at (C.south west) {\small Scala};}
 | |
| 934 | ||
| 935 |   \onslide<3->{
 | |
| 936 |   \node (D) at (6.8,0)  [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
 | |
| 937 |   \node [below right] at (D.north west) {\small V1.00};
 | |
| 938 | ||
| 939 |   \node (E) at (6.8,2)  [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
 | |
| 940 |   \node [below right] at (E.north west) {\small V1.01};}
 | |
| 941 | ||
| 942 |   \onslide<4->{
 | |
| 943 |   \node (F) at (8.6,0)  [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
 | |
| 944 |   \node [below right] at (F.north west) {\small V1.01};
 | |
| 945 | ||
| 946 |   \node (G) at (8.6,2)  [draw=black, rectangle, very thick, minimum height=18mm, minimum width=14mm] {};
 | |
| 947 |   \node [below right] at (G.north west) {\small V1.02};
 | |
| 948 |   \node at (9.8,0) {\ldots};
 | |
| 949 |   \node at (9.8,2) {\ldots};
 | |
| 950 |   \node at (8,-2) {\textcolor{gray}{\begin{tabular}{@{}l@{}}no host language\\needed\end{tabular}}};
 | |
| 951 | } | |
| 952 | ||
| 953 |   \end{tikzpicture}
 | |
| 954 |   \end{center}
 | |
| 955 | ||
| 956 | \end{frame}}
 | |
| 957 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 958 | ||
| 959 | ||
| 960 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 961 |   \mode<presentation>{
 | |
| 962 |   \begin{frame}<1-3>
 | |
| 963 |   \frametitle{\LARGE\begin{tabular}{c}Hacking Compilers 
 | |
| 964 |   \end{tabular}}
 | |
| 965 | ||
| 966 | %Why is it so paramount to have a small trusted code base (TCB)? | |
| 967 | \bigskip\bigskip | |
| 968 | ||
| 969 |   \begin{columns}
 | |
| 970 |   \begin{column}{2.7cm}
 | |
| 971 |   \begin{minipage}{2.5cm}%
 | |
| 972 |   \begin{tabular}{c@ {}}
 | |
| 973 |   \includegraphics[scale=0.2]{../pics/ken-thompson.jpg}\\[-1.8mm]
 | |
| 974 | \footnotesize Ken Thompson\\[-1.8mm] | |
| 975 | \footnotesize Turing Award, 1983\\ | |
| 976 |   \end{tabular}
 | |
| 977 |   \end{minipage}
 | |
| 978 |   \end{column}
 | |
| 979 |   \begin{column}{9cm}
 | |
| 980 |   \begin{tabular}{l@ {\hspace{1mm}}p{8cm}}
 | |
| 981 | ||
| 982 | & Ken Thompson showed how to hide a Trojan Horse in a | |
| 983 |   compiler \textcolor{red}{without} leaving any traces in the source code.\\[2mm]
 | |
| 984 | ||
| 985 | & No amount of source level verification will protect | |
| 986 | you from such Thompson-hacks.\\[2mm] | |
| 987 | ||
| 988 |   \end{tabular}
 | |
| 989 |   \end{column}
 | |
| 990 |   \end{columns}
 | |
| 991 | ||
| 992 |   \only<2>{
 | |
| 993 |   \begin{textblock}{6}(4,2)
 | |
| 994 |   \begin{tikzpicture}
 | |
| 995 | \draw (0,0) node[inner sep=3mm,fill=cream, ultra thick, draw=red, rounded corners=2mm] | |
| 996 |   {\normalsize
 | |
| 997 |   \begin{minipage}{8cm}
 | |
| 998 |   \begin{quote}
 | |
| 999 |   \includegraphics[scale=0.05]{../pics/evil.png}
 | |
| 1000 |   \begin{enumerate}
 | |
| 1001 | \item[1)] Assume you ship the compiler as binary and also with sources. | |
| 1002 | \item[2)] Make the compiler aware when it compiles itself. | |
| 1003 | \item[3)] Add the Trojan horse. | |
| 1004 | \item[4)] Compile. | |
| 1005 | \item[5)] Delete Trojan horse from the sources of the compiler. | |
| 1006 |   \item[6)] Go on holiday for the rest of your life. ;o)\\[-7mm]\mbox{}
 | |
| 1007 |   \end{enumerate}
 | |
| 1008 |   \end{quote}
 | |
| 1009 |   \end{minipage}};
 | |
| 1010 |   \end{tikzpicture}
 | |
| 1011 |   \end{textblock}}
 | |
| 1012 | ||
| 1013 |   \end{frame}}
 | |
| 1014 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1015 | ||
| 701 | 1016 | |
| 1017 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1018 |   \begin{frame}[c]
 | |
| 1019 |   \frametitle{Dijkstra on Testing}
 | |
| 1020 | ||
| 1021 |   \begin{bubble}[10cm]
 | |
| 1022 | ``Program testing can be a very effective way to show the | |
| 1023 | presence of bugs, but it is hopelessly inadequate for showing | |
| 1024 | their absence.'' | |
| 1025 |   \end{bubble}\bigskip
 | |
| 1026 | ||
| 1027 | \small | |
| 1028 | What is good about compilers: the either seem to work, | |
| 1029 | or go horribly wrong (most of the time). | |
| 1030 | ||
| 1031 |   \end{frame}
 | |
| 1032 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1033 | ||
| 1034 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1035 | \begin{frame}[c]
 | |
| 1036 | \frametitle{\Large Proving Programs to be Correct}
 | |
| 1037 | ||
| 1038 | \begin{bubble}[10cm]
 | |
| 1039 | \small | |
| 1040 | {\bf Theorem:} There are infinitely many prime 
 | |
| 1041 | numbers.\medskip\\ | |
| 1042 | ||
| 1043 | {\bf Proof} \ldots\\
 | |
| 1044 | \end{bubble}\bigskip
 | |
| 1045 | ||
| 1046 | ||
| 1047 | similarly\bigskip | |
| 1048 | ||
| 1049 | \begin{bubble}[10cm]
 | |
| 1050 | \small | |
| 1051 | {\bf Theorem:} The program is doing what 
 | |
| 1052 | it is supposed to be doing.\medskip | |
| 1053 | ||
| 1054 | {\bf Long, long proof} \ldots\\
 | |
| 1055 | \end{bubble}\bigskip\medskip
 | |
| 1056 | ||
| 1057 | \small This can be a gigantic proof. The only hope is to have | |
| 1058 | help from the computer. `Program' is here to be understood to be | |
| 1059 | quite general (compiler, OS, \ldots). | |
| 1060 | ||
| 1061 | \end{frame}
 | |
| 1062 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1063 | ||
| 1064 | ||
| 1065 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1066 | ||
| 1067 | \begin{frame}[c]
 | |
| 1068 | \frametitle{Can This Be Done?}
 | |
| 1069 | ||
| 1070 | \begin{itemize}
 | |
| 1071 | \item in 2008, verification of a small C-compiler | |
| 1072 | \begin{itemize}
 | |
| 1073 | \item ``if my input program has a certain behaviour, then the compiled machine code has the same behaviour'' | |
| 1074 | \item is as good as \texttt{gcc -O1}, but much, much less buggy 
 | |
| 1075 | \end{itemize}
 | |
| 1076 | \end{itemize}
 | |
| 1077 | ||
| 1078 | \begin{center}
 | |
| 1079 |   \includegraphics[scale=0.12]{../pics/compcert.png}
 | |
| 1080 | \end{center}
 | |
| 1081 | ||
| 1082 | \end{frame}
 | |
| 1083 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1084 | ||
| 1085 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1086 | \begin{frame}[t]
 | |
| 1087 | \frametitle{Fuzzy Testing C-Compilers}
 | |
| 1088 | ||
| 1089 | \begin{itemize}
 | |
| 1090 | \item tested GCC, LLVM and others by randomly generating | |
| 1091 | C-programs | |
| 1092 | \item found more than 300 bugs in GCC and also | |
| 1093 | many in LLVM (some of them highest-level critical)\bigskip | |
| 1094 | \item about CompCert: | |
| 1095 | ||
| 1096 | \begin{bubble}[10.7cm]\small ``The striking thing about our CompCert
 | |
| 1097 | results is that the middle-end bugs we found in all other | |
| 1098 | compilers are absent. As of early 2011, the under-development | |
| 1099 | version of CompCert is the only compiler we have tested for | |
| 1100 | which Csmith cannot find wrong-code errors. This is not for | |
| 1101 | lack of trying: we have devoted about six CPU-years to the | |
| 1102 | task.'' | |
| 1103 | \end{bubble} 
 | |
| 1104 | \end{itemize}
 | |
| 1105 | ||
| 1106 | \end{frame}
 | |
| 1107 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1108 | ||
| 1109 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1110 | ||
| 1111 | \begin{frame}[c]
 | |
| 1112 | \frametitle{Next Week}
 | |
| 1113 | ||
| 1114 | \begin{itemize}
 | |
| 1115 | \item Revision Lecture\medskip | |
| 1116 | \item How many  strings are in $\bl{L(a^*)}$?\pause\medskip
 | |
| 1117 | \item How many  strings are in $\bl{L((a + b)^*)}$?\\ Are there more than
 | |
| 1118 |   in $\bl{L(a^*)}$?
 | |
| 1119 | \end{itemize}
 | |
| 1120 | ||
| 1121 | ||
| 1122 | ||
| 1123 | \end{frame}
 | |
| 1124 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1125 | ||
| 822 | 1126 | \begin{frame}<1-20>[c]
 | 
| 1127 | \end{frame}
 | |
| 701 | 1128 | |
| 1129 | \end{document}
 | |
| 1130 | ||
| 1131 | %%% Local Variables: | |
| 1132 | %%% mode: latex | |
| 1133 | %%% TeX-master: t | |
| 1134 | %%% End: | |
| 1135 | ||
| 1136 | ||
| 1137 | ||
| 1138 | ||
| 1139 | ||
| 610 | 1140 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | 
| 1141 |   \begin{frame}[c]
 | |
| 1142 | ||
| 1143 |   \begin{center}
 | |
| 1144 |   \includegraphics[scale=0.6]{../pics/bridge-limits.png}
 | |
| 1145 |   \end{center}
 | |
| 1146 | ||
| 1147 |   \end{frame}
 | |
| 1148 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1149 | ||
| 1150 | ||
| 1151 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1152 | \begin{frame}[c]
 | |
| 1153 | \frametitle{Compilers \& Boeings 777}
 | |
| 1154 | ||
| 1155 | First flight in 1994. They want to achieve triple redundancy in hardware | |
| 1156 | faults.\bigskip | |
| 1157 | ||
| 1158 | They compile 1 Ada program to\medskip | |
| 1159 | ||
| 1160 | \begin{itemize}
 | |
| 1161 | \item Intel 80486 | |
| 1162 | \item Motorola 68040 (old Macintosh's) | |
| 1163 | \item AMD 29050 (RISC chips used often in laser printers) | |
| 1164 | \end{itemize}\medskip
 | |
| 1165 | ||
| 1166 | using 3 independent compilers.\bigskip\pause | |
| 1167 | ||
| 1168 | \small Airbus uses C and static analysers. Recently started using CompCert. | |
| 1169 | ||
| 1170 | \end{frame}
 | |
| 1171 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1172 | ||
| 1173 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1174 | \begin{frame}[c]
 | |
| 1175 | \frametitle{Goal}
 | |
| 1176 | ||
| 1177 | Remember the Bridges example? | |
| 1178 | ||
| 1179 | \begin{itemize}
 | |
| 1180 | \item Can we look at our programs and somehow ensure | |
| 1181 | they are bug free/correct?\pause\bigskip | |
| 1182 | ||
| 1183 | \item Very hard: Anything interesting about programs is equivalent | |
| 1184 | to the Halting Problem, which is undecidable.\pause\bigskip | |
| 1185 | ||
| 1186 | \item \alert{Solution:} We avoid this ``minor'' obstacle by
 | |
| 1187 | being as close as possible of deciding the halting | |
| 1188 | problem, without actually deciding the halting problem. | |
| 1189 | \small$\quad\Rightarrow$ yes, no, don't know (static analysis) | |
| 1190 | \end{itemize}
 | |
| 1191 | ||
| 1192 | \end{frame}
 | |
| 1193 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1194 | ||
| 1195 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1196 |   \begin{frame}[c]
 | |
| 1197 |   \frametitle{What is Static Analysis?}
 | |
| 1198 | ||
| 1199 |   \begin{center}
 | |
| 1200 |   \includegraphics[scale=0.4]{../pics/state.png}
 | |
| 1201 |   \end{center}
 | |
| 1202 | ||
| 1203 |   \begin{itemize}
 | |
| 1204 | \item depending on some initial input, a program | |
| 1205 | (behaviour) will ``develop'' over time. | |
| 1206 |   \end{itemize}
 | |
| 1207 | ||
| 1208 |   \end{frame}
 | |
| 1209 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1210 | ||
| 1211 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1212 |   \begin{frame}[c]
 | |
| 1213 |   \frametitle{What is Static Analysis?}
 | |
| 1214 | ||
| 1215 |   \begin{center}
 | |
| 1216 |   \includegraphics[scale=0.4]{../pics/state2.png}
 | |
| 1217 |   \end{center}
 | |
| 1218 | ||
| 1219 |   \end{frame}
 | |
| 1220 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1221 | ||
| 1222 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1223 |   \begin{frame}[c]
 | |
| 1224 |   \frametitle{What is Static Analysis?}
 | |
| 1225 | ||
| 1226 |   \begin{center}
 | |
| 1227 |   \includegraphics[scale=0.4]{../pics/state3.jpg}
 | |
| 1228 |   \end{center}
 | |
| 1229 | ||
| 1230 |   \end{frame}
 | |
| 1231 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1232 | ||
| 1233 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1234 |   \begin{frame}[c]
 | |
| 1235 |   \frametitle{What is Static Analysis?}
 | |
| 1236 | ||
| 1237 |   \begin{center}
 | |
| 1238 |   \includegraphics[scale=0.4]{../pics/state4.jpg}
 | |
| 1239 |   \end{center}
 | |
| 1240 | ||
| 1241 |   \begin{itemize}
 | |
| 1242 | \item to be avoided | |
| 1243 |   \end{itemize}
 | |
| 1244 | ||
| 1245 |   \end{frame}
 | |
| 1246 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1247 | ||
| 1248 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1249 |   \begin{frame}[c]
 | |
| 1250 |   \frametitle{What is Static Analysis?}
 | |
| 1251 | ||
| 1252 |   \begin{center}
 | |
| 1253 |   \includegraphics[scale=0.4]{../pics/state5.png}
 | |
| 1254 |   \end{center}
 | |
| 1255 | ||
| 1256 |   \begin{itemize}
 | |
| 1257 | \item this needs more work | |
| 1258 |   \end{itemize}
 | |
| 1259 | ||
| 1260 |   \end{frame}
 | |
| 1261 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1262 | ||
| 1263 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1264 |   \begin{frame}[c]
 | |
| 1265 |   \frametitle{What is Static Analysis?}
 | |
| 1266 | ||
| 1267 |   \begin{center}
 | |
| 1268 |   \includegraphics[scale=0.4]{../pics/state6.png}
 | |
| 1269 |   \end{center}
 | |
| 1270 | ||
| 1271 |   \end{frame}
 | |
| 1272 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1273 | ||
| 1274 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1275 |   \begin{frame}[c,fragile]
 | |
| 1276 |     \frametitle{\Large\begin{tabular}{c}Concrete Example:\\[-1mm]
 | |
| 1277 |                   Are Vars Definitely Initialised?\end{tabular}}
 | |
| 1278 | ||
| 1279 | Assuming \texttt{x} is initialised, what about \texttt{y}?\bigskip
 | |
| 1280 | ||
| 1281 | Prog.~1:\\ | |
| 1282 | \begin{lstlisting}[numbers=none,
 | |
| 1283 | basicstyle=\ttfamily, | |
| 1284 | language=While,xleftmargin=3mm] | |
| 1285 | if x < 1 then y := x else y := x + 1; | |
| 1286 | y := y + 1 | |
| 1287 | \end{lstlisting}\medskip     
 | |
| 1288 | ||
| 1289 | Prog.~2:\\ | |
| 1290 | \begin{lstlisting}[numbers=none,
 | |
| 1291 | basicstyle=\ttfamily, | |
| 1292 | language=While,xleftmargin=3mm] | |
| 1293 | if x < x then y := y + 1 else y := x; | |
| 1294 | y := y + 1 | |
| 1295 | \end{lstlisting}            
 | |
| 1296 | ||
| 1297 |   \end{frame}
 | |
| 1298 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1299 | ||
| 1300 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1301 |   \begin{frame}[c,fragile]
 | |
| 1302 |     \frametitle{\Large\begin{tabular}{c}Concrete Example:\\[-1mm]
 | |
| 1303 |                   Are Vars Definitely Initialised?\end{tabular}}
 | |
| 1304 | ||
| 1305 | What should the rules be for deciding when a | |
| 1306 | variable is initialised?\bigskip\pause | |
| 1307 | ||
| 1308 | \begin{itemize}
 | |
| 1309 | \item variable \texttt{x} is definitely initialized after
 | |
| 1310 |   \texttt{skip}\\
 | |
| 1311 |   iff \texttt{x} is definitely initialized before \texttt{skip}.
 | |
| 1312 | \end{itemize}
 | |
| 1313 | ||
| 1314 | \end{frame}
 | |
| 1315 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1316 | ||
| 1317 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1318 |   \begin{frame}[c,fragile]
 | |
| 1319 | %    \frametitle{\Large\begin{tabular}{c}Concrete Example:\\[-1mm]
 | |
| 1320 | %                  Are Vars Definitely Initialised?\end{tabular}}
 | |
| 1321 | ||
| 1322 | $\bl{A}$ is the set of definitely defined variables:
 | |
| 1323 | ||
| 1324 | \begin{center}
 | |
| 1325 | \begin{tabular}{c}
 | |
| 612 | 1326 |   \bl{\infer{\mbox{}}{A\triangleright\texttt{skip}\triangleright{}A}}\qquad
 | 
| 1327 |   \bl{\infer{vars(a) \subseteq A}{A\triangleright
 | |
| 1328 |   (\texttt{x\,:=\,a})\triangleright\{x\}\cup A}}
 | |
| 610 | 1329 | \medskip\\\pause | 
| 1330 | ||
| 612 | 1331 |   \bl{\infer{A_1\triangleright{}s_1\triangleright{}A_2
 | 
| 1332 |   \quad A_2\triangleright{}s_2\triangleright{}A_3}
 | |
| 1333 |   {A_1\triangleright{}(s_1 ; s_2)\triangleright{}A_3}}
 | |
| 610 | 1334 | \medskip\\\pause | 
| 1335 | ||
| 612 | 1336 |   \bl{\infer{vars(b)\subseteq A\quad A\triangleright{}s_1\triangleright{}A_1
 | 
| 1337 |   \quad A\triangleright{}s_2\triangleright{}A_2}
 | |
| 1338 |   {A\triangleright(\texttt{if}\;b\;\texttt{then}\;s_1\;\texttt{else}\;s_2)\triangleright{}A_1\cap A_2}}
 | |
| 610 | 1339 | \medskip\\\pause | 
| 1340 | ||
| 612 | 1341 |   \bl{\infer{vars(b)\subseteq A\quad A\triangleright{}s\triangleright{}A'}
 | 
| 1342 |   {A\triangleright(\texttt{while}\;b\;\texttt{do}\;s)\triangleright{}A}}\pause
 | |
| 610 | 1343 | \end{tabular}  
 | 
| 1344 | \end{center}
 | |
| 1345 | ||
| 1346 | \hfill we start with $\bl{A = \{\}}$
 | |
| 1347 | \end{frame}
 | |
| 1348 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 1349 |