Add a few slides

shared/imgs/call_stack.png

@@ -0,0 +1 @@
+../../report/imgs/call_stack/call_stack.png

shared/todo.sty

@@ -8,4 +8,4 @@
 \newcommand{\qtodo}[1]{\colorbox{todobg}{\textcolor{todofg}{#1}}}
 \newcommand{\todo}[1]{\qtodo{\textbf{TODO:}\,#1}}
 \newcommand{\qnote}[1]{\colorbox{notebg}{\textcolor{notefg}{#1}}}
-\newcommand{\note}[1]{\qnote{\textbf{NOTE:}\,#1}}
+\newcommand{\tnote}[1]{\qnote{\textbf{NOTE:}\,#1}}

slides/slides.tex

@@ -8,7 +8,13 @@
 \usepackage{amsmath}
 \usepackage{amsfonts}
 \usepackage{amssymb}
-\usepackage{my_listings}
+
+\usepackage{../shared/my_listings}
+%\usepackage{../shared/my_hyperref}
+\usepackage{../shared/specific}
+\usepackage{../shared/common}
+\usepackage{../shared/todo}
+
 \setbeamertemplate{navigation symbols}{}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -38,4 +44,123 @@
     \tableofcontents
 \end{frame}
 
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\section{Stack unwinding data}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\subsection{Introduction}
+
+\begin{frame}[fragile]{We often use stack unwinding!}
+    \begin{lstlisting}[language=, numbers=none, escapechar=|]
+Program received signal SIGSEGV, Segmentation fault.
+0x0000555555554625 in fct_b (m=0x5c) at segfault.c:5
+5           printf("%l\n", *m);
+|\pause|
+(gdb) backtrace
+#0  0x0000555555554625 in fct_b (m=0x5c) at segfault.c:5
+#1  0x0000555555554663 in fct_a (n=42) at segfault.c:10
+#2  0x0000555555554674 in main () at segfault.c:14
+|\pause|
+(gdb) frame 1
+#1  0x0000555555554663 in fct_a (n=42) at segfault.c:10
+10          fct_b((int*)(some_fct_a_var + 8));
+|\pause|
+(gdb) print some_fct_a_var
+$1 = 84
+    \end{lstlisting}
+
+    \pause{}
+    \begin{center}
+        \textbf{\Large How does it work?!}
+    \end{center}
+    \vspace{1em}
+\end{frame}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\subsection{Stack frames and unwinding}
+
+\begin{frame}{Call stack and registers}
+    \begin{columns}[c]
+        \begin{column}{0.65\textwidth}
+            \begin{itemize}
+                \item Programs use a \alert{call stack}
+                \item Organized in \alert{stack frames}
+                    \begin{itemize}
+                        \item Local variables
+                        \item Function parameters
+                        \item Keep track of nesting, registers and ``return
+                            point''
+                    \end{itemize}
+            \end{itemize}
+
+            Common registers:
+            \begin{itemize}
+                \item \reg{rip}: program counter (PC)
+
+                \item \reg{rsp}: stack pointer
+
+                \item \reg{rbp}: base pointer
+                    \begin{itemize}
+                        \item Saves \reg{rsp}
+                        \item Easy access
+                        \item Wastes a register
+                        \item Not often used (x86\_64)
+                    \end{itemize}
+            \end{itemize}
+        \end{column}
+        \begin{column}{0.35\textwidth}
+            \includegraphics[width=0.95\linewidth]{../shared/imgs/call_stack}
+        \end{column}
+    \end{columns}
+\end{frame}
+
+\begin{frame}{Isn't it as trivial as \texttt{pop()}?}
+    \begin{itemize}
+        \item This is only a \alert{blob of binary data} without mandatory
+            structure
+        \item We ignore \alert{which registers were saved}
+        \item We ignore \alert{whether \reg{rbp} was used}
+        \item We ignore \alert{where the return address is stored}
+        \item We ignore \alert{where the previous frame begins}
+    \end{itemize}
+
+    \medskip
+
+    But\ldots{} if we know how to \alert{unwind one}, we can \alert{recurse}!
+\end{frame}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\subsection{DWARF tables}
+
+\begin{frame}[fragile]{DWARF unwinding data}
+
+    \begin{lstlisting}[numbers=none, language=]
+00009b30 48 009b34 FDE cie=0000 pc=0084950..0084b37
+ LOC    CFA      rbx   rbp   r12   r13   r14   r15   ra
+0084950 rsp+8    u     u     u     u     u     u     c-8
+0084952 rsp+16   u     u     u     u     u     c-16  c-8
+0084954 rsp+24   u     u     u     u     c-24  c-16  c-8
+0084956 rsp+32   u     u     u     c-32  c-24  c-16  c-8
+0084958 rsp+40   u     u     c-40  c-32  c-24  c-16  c-8
+0084959 rsp+48   u     c-48  c-40  c-32  c-24  c-16  c-8
+008495a rsp+56   c-56  c-48  c-40  c-32  c-24  c-16  c-8
+0084962 rsp+64   c-56  c-48  c-40  c-32  c-24  c-16  c-8
+0084a19 rsp+56   c-56  c-48  c-40  c-32  c-24  c-16  c-8
+0084a1d rsp+48   c-56  c-48  c-40  c-32  c-24  c-16  c-8
+0084a1e rsp+40   c-56  c-48  c-40  c-32  c-24  c-16  c-8
+0084a20 rsp+32   c-56  c-48  c-40  c-32  c-24  c-16  c-8
+0084a22 rsp+24   c-56  c-48  c-40  c-32  c-24  c-16  c-8
+0084a24 rsp+16   c-56  c-48  c-40  c-32  c-24  c-16  c-8
+0084a26 rsp+8    c-56  c-48  c-40  c-32  c-24  c-16  c-8
+0084a30 rsp+64   c-56  c-48  c-40  c-32  c-24  c-16  c-8
+    \end{lstlisting}
+
+    \pause{}
+
+    \vspace{-4cm}
+    \hfill\includegraphics[height=3cm, angle=45, origin=c]{img/dwarf_logo}
+    \hspace{-1cm}
+
+\end{frame}
+
 \end{document}