Add demo files

demo.old/demo.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int bar(int x) {
+	printf("'I’m %d; how many? %n\n", x, &x);
+	return x;
+}
+
+int foo() {
+	return bar(3);
+}
+
+int main() {
+	return foo();
+}

demo.old/synth.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+SYNTHESIS_SCRIPT="../../../src/dwarf-synthesis/synthesize_dwarf.sh"
+
+if [ "$#" -lt 1 ] ; then
+    >&2 echo -e "Missing argument: object file.\nUsage: $0 object.o"
+    exit 1
+fi
+
+objfile="$1"
+
+$SYNTHESIS_SCRIPT "$objfile" "$objfile.synth"

demo/.gitignore

@@ -0,0 +1,2 @@
+dwarf-synthesis
+tests/data*

demo/Makefile

@@ -0,0 +1,9 @@
+all:
+	@>&2 echo "Please provide an explicit target"
+	@exit 1
+
+tests/data:
+	dd if=/dev/urandom of="$@" bs=512K count=4
+
+clean:
+	rm -f tests/data.gz tests/gzip.synth

slides.tex

@@ -17,6 +17,7 @@
 \usepackage{multirow}
 \usepackage[many]{tcolorbox}
 \usepackage[absolute,overlay]{textpos}
+\usetikzlibrary{arrows.meta}
 
 \usepackage{texlib/my_listings}
 \usepackage{texlib/specific}
@@ -129,7 +130,7 @@
 \begin{frame}[fragile]{}
     \begin{columns}[c]
         \begin{column}{0.65\textwidth}
-            \begin{lstlisting}[language=gdb, numbers=none, escapechar=|]
+            \begin{lstlisting}[basicstyle=\tt,language=gdb, numbers=none, escapechar=|]
 $ ./a.out
 Segmentation fault.
 
@@ -240,22 +241,26 @@ Segmentation fault.
             by a \alert{Turing-complete stack machine}!}
     \end{itemize}
 
-    \pause{}
+    \only<2->{
+        \begin{textblock*}{0.90\textwidth}[0.5,0](0.5\paperwidth,0.17\paperheight)%
+            \begin{tcolorbox}[halign=center, colframe=red, colback=Lavender]
+                \bf \huge
+                Complex \,\& \,slow
+            \end{tcolorbox}
+        \end{textblock*}
+    }
 
-    \vspace{-5cm}
-    \begin{tcolorbox}[halign=center, colframe=red, colback=Lavender]
-        \bf \huge
-        Complex \,\& \,slow
-    \end{tcolorbox}
-
-	\pause{}
-    \begin{tcolorbox}[halign=center, colframe=red, colback=Lavender]
-        \huge
-        \textbf{Pervasive:}\\ relied upon by debuggers, profilers, C++
-        exceptions \\
-        \medskip{}
-        \textbf{$\leadsto$ not only for debuggers!}
-	\end{tcolorbox}
+    \only<3->{
+        \begin{textblock*}{0.90\textwidth}[0.5,0](0.5\paperwidth,0.35\paperheight)%
+            \begin{tcolorbox}[halign=center, colframe=red, colback=Lavender]
+                \huge
+                \textbf{Pervasive:}\\ relied upon by debuggers, profilers, C++
+                exceptions \\
+                \medskip{}
+                \textbf{$\leadsto$ not only for debuggers!}
+            \end{tcolorbox}
+        \end{textblock*}
+    }
 \end{frame}
 
 \newcommand{\LinusMailOne}{
@@ -403,7 +408,7 @@ Segmentation fault.
 
 \begin{frame}{How do we actually synthesize?}
     \begin{itemize}
-        \item Upon entering a function, we know (ABI)
+        \item Upon entering a function, we know
             \[ \cfa = \reg{rsp} - 8
             \qquad \ra = \cfa + 8 \]
         \item The semantics of each instruction specifies \alert{how it changes \cfa}.
@@ -435,31 +440,52 @@ Segmentation fault.
 
 \subsection{Compilation ahead-of-time}
 
-\begin{frame}
-    \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 contains assembly that computes a \alert{row of the
-            table}
-    \end{itemize}
-\end{frame}
-
-
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \begin{frame}[shrink]
-    \lstinputlisting[language=C]{src/fib7/fib7.eh_elf_basic.c}
+    \vspace{0.5cm}
+    \begin{tikzpicture}
+        \begin{scope}[every node/.style={rectangle,thick,draw,scale=0.95}]
+            \node (dwarf) at (0, 0) {
+                \lstinputlisting[basicstyle=\tiny\tt,numbers=none,language=]{src/dw_plt_abbr}
+            };
 
-    \pause{}
-    \vspace{1em}
-    \begin{center}
-        The real code is optimised, but boils down to this.
-    \end{center}
+            \only<2->{
+                \node (table) at (0.5\textwidth, -0.23\textheight) {
+                    \tiny\tt
+                    \begin{tabular}{
+                            >{\columncolor{YellowGreen}}l
+                            >{\columncolor{Thistle}}l
+                            l l
+                        >{\columncolor{Apricot}}l}
+                        LOC & CFA & rbx & rbp & ra \\
+                        0084950 & rsp+8 & u & u & c-8 \\
+                        0084952 & rsp+16 & u & u & c-8 \\
+                        0084954 & rsp+24 & u & u & c-8 \\
+                        0084956 & rsp+32 & u & u & c-8 \\
+                    \end{tabular}
+                };
+            }
+            \only<3->{
+                \node (csrc) at (0, -0.6\textheight) {
+                    \lstinputlisting[basicstyle=\tiny,numbers=none,language=C]{src/fib7/fib7.eh_elf_basic.c}
+                };
+                \node (ehelf) at (0.55\textwidth, -0.75\textheight) {
+                    ELF file:
+                    ``\ehelf{}''
+                };
+            }
+        \end{scope}
+
+        \begin{scope}[>={Stealth[black]},
+                every node/.style={fill=white,rectangle},
+                every path/.style={draw=black,very thick}]
+            \only<2->{\path [->] (dwarf) -| node {runtime} (table);}
+            \only<3->{
+                \path [->] (dwarf) edge node {ahead of time} (csrc);
+                \path [->] (csrc) -| node {gcc, AoT} (ehelf);
+            }
+        \end{scope}
+    \end{tikzpicture}
 \end{frame}
 
 
@@ -505,16 +531,14 @@ Segmentation fault.
 \section*{Conclusion}
 \setcounter{section}{0}
 
-\begin{frame}
-    The original article \textbf{Reliable and Fast DWARF-based Stack Unwinding}
-    contains
-
-    \vspace{1em}
-
+\begin{frame}{A lot of things remain to be done!}
     \begin{itemize}
-        \item{} DWARF unwinding tables validation;
-        \item{} DWARF unwinding tables synthesis;
-        \item{} DWARF-based unwinding speedup.
+        \item{} Synthesis + compare = verification of unwinding data!
+        \item{} Synthesis could be integrated in compilers: support for inline
+            assembly, fallback, \ldots
+        \item{} Speedup could be implemented in profilers, debuggers,
+            \ldots{}
+        \item{} Probably many more cool things to do!
     \end{itemize}
 
     \vspace{1em}

src/dw_plt

@@ -0,0 +1,7 @@
+30 24 34 FDE pc=004020..004040
+  DW_CFA_def_cfa_offset: 16
+  DW_CFA_advance_loc: 6 to 0000000000004026
+  DW_CFA_def_cfa_offset: 24
+  DW_CFA_advance_loc: 10 to 0000000000004030
+  DW_CFA_def_cfa_expression (DW_OP_breg7 (rsp): 8; DW_OP_breg16 (rip): 0; DW_OP_lit15; DW_OP_and; DW_OP_lit11; DW_OP_ge; DW_OP_lit3; DW_OP_shl; DW_OP_plus)
+  [...]

src/dw_plt_abbr

@@ -0,0 +1,7 @@
+30 24 34 FDE pc=004020..004040
+  DW_CFA_def_cfa_offset: 16
+  DW_CFA_advance_loc: 6 to 0000000000004026
+  DW_CFA_def_cfa_offset: 24
+  DW_CFA_advance_loc: 10 to 0000000000004030
+  DW_CFA_def_cfa_expression (DW_OP_breg7 (rsp): 8;
+    DW_OP_breg16 (rip): 0; ...)