Add a few slides

slides/slides.tex

@@ -17,6 +17,8 @@
 
 \setbeamertemplate{navigation symbols}{}
 
+\newcommand{\thenalert}[1]{\only<1>{#1}\only<2>{\alert{#1}}}
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \author[Théophile Bastian]{Théophile \textsc{Bastian} \\
     \small{Under supervision of Francesco Zappa Nardelli}}
@@ -163,4 +165,128 @@ $1 = 84
 
 \end{frame}
 
+\begin{frame}[fragile]{The real DWARF}
+    \begin{lstlisting}[numbers=none, language=]
+00009b30 48 009b34 FDE cie=0000 pc=0084950..0084b37
+  DW_CFA_advance_loc: 2 to 0000000000084952
+  DW_CFA_def_cfa_offset: 16
+  DW_CFA_offset: r15 (r15) at cfa-16
+  DW_CFA_advance_loc: 2 to 0000000000084954
+  DW_CFA_def_cfa_offset: 24
+  DW_CFA_offset: r14 (r14) at cfa-24
+  DW_CFA_advance_loc: 2 to 0000000000084956
+  DW_CFA_def_cfa_offset: 32
+  DW_CFA_offset: r13 (r13) at cfa-32
+  DW_CFA_advance_loc: 2 to 0000000000084958
+  DW_CFA_def_cfa_offset: 40
+  DW_CFA_offset: r12 (r12) at cfa-40
+  DW_CFA_advance_loc: 1 to 0000000000084959
+  DW_CFA_def_cfa_offset: 48
+  DW_CFA_offset: r6 (rbp) at cfa-48
+  DW_CFA_advance_loc: 1 to 000000000008495a
+  [...]
+    \end{lstlisting}
+\end{frame}
+
+\begin{frame}{Why does slow matter?}
+    \textbf{Do we really care about speed for unwinding?}
+    \begin{itemize}
+
+        \item{} After all, we're talking about \alert{debugging procedures} ran
+            by a \alert{human being} (slower than the machine).
+
+            \ldots{}or are we?
+
+        \pause{}\item{} \alert{Profiling} with polling profilers
+
+        \pause{}\item{} \alert{Exception handling} in C++
+
+    \end{itemize}
+
+    \vspace{2em}
+
+    \begin{center}
+        \textbf{Debug data is not only for debugging}
+    \end{center}
+\end{frame}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\section{Compiling DWARF}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\subsection{Compilation Strategy}
+
+\begin{frame}[fragile]{Types}
+    Generated data:
+    \lstinputlisting[language=C]{src/unwind_context.c}
+    \pause{}
+
+    \vspace{1em}
+    Function type:
+    \begin{lstlisting}[language=C]
+unwind_context_t _eh_elf(
+    unwind_context_t, instruction_pointer_t); \end{lstlisting}
+\end{frame}
+
+\begin{frame}{Compilation overview}
+    \begin{itemize}
+        \item Compiled to \alert{C code}
+        \item C code then \alert{compiled to native binary} (gcc)
+            \begin{itemize}
+                \item[$\leadsto$] gcc optimisations for free
+            \end{itemize}
+        \item Compiled as \alert{separate \texttt{.so} files}, called \ehelfs{}
+            \bigskip{}
+        \item Morally a \alert{monolithic switch} on IPs
+        \item Each case fills the context structure
+    \end{itemize}
+\end{frame}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\subsection{Outlining}
+
+\begin{frame}{Size optimisation: outlining}
+    \begin{itemize}
+        \item This \alert{works}, but \alert{takes space}: about \alert{7 times
+            heavier} than regular DWARF\@.
+
+        \item DWARF optimisation strategy: \alert{alter previous row}. \\
+            Causes slowness: we cannot do that.
+
+        \item Remark: a lot of lines appear often.
+            \begin{itemize}
+                \item[$\leadsto$] \emph{outline} them!
+            \end{itemize}
+    \end{itemize}
+
+    \pause{}
+
+    \textbf{Outlining:}
+    \begin{itemize}
+        \item Turn the big switch into a binary search \alert{if/else tree}
+        \item \alert{Extract} the conditional bodies, put them afterwards
+        \item Jump to them using a \alert{label/goto}
+    \end{itemize}
+
+    \pause{}
+
+    \bigskip{}
+    \begin{center}
+        $\leadsto$ only \textbf{2.5 times heavier than DWARF}
+    \end{center}
+\end{frame}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\section{Benchmarking}
+
+\begin{frame}{Benchmarking requirements}
+    \todo{}
+\end{frame}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\subsection{}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\section{A glance at future work}
+
 \end{document}

slides/src/unwind_context.c

@@ -0,0 +1,4 @@
+typedef struct {
+    uint8_t flags;  // State (registers filled, error)
+    uintptr_t rip, rsp, rbp, rbx;  // Registers' values
+} unwind_context_t;