From 86012c7d5e05a156f2c4d247b127a402c45ab02f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9ophile=20Bastian?= <contact@tobast.fr>
Date: Sat, 4 Aug 2018 13:33:00 +0200
Subject: [PATCH] Write more about C++ exn

---
 report/report.tex | 11 +++++++++++
 shared/report.bib | 18 ++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/report/report.tex b/report/report.tex
index 6ad375c..644b87a 100644
--- a/report/report.tex
+++ b/report/report.tex
@@ -177,6 +177,17 @@ necessary to be able to unwind frames, one by one, until a suitable
 \lstc{catch} block is found. The C++ language, for one, includes a
 stack-unwinding library similar to \prog{libunwind} in its runtime.
 
+Technically, exception handling could be implemented without any stack
+unwinding, by using \lstc{setjmp}/\lstc{longjmp} mechanics~\cite{niditoexn}.
+However, this is not possible in C++ (and some other languages), because the
+stack needs to be properly unwound in order to trigger the destructors of
+stack-allocated objects. Furthermore, this is often undesirable: \lstc{setjmp}
+has a quite big overhead, which is introduced whenever a \lstc{try} block is
+encountered. Instead, it is often preferred to have strictly no overhead when
+no exception happens, at the cost of a greater overhead when an exception is
+actually fired (after all, they are supposed to be \emph{exceptional}). For
+more details on C++ exception handling, see~\cite{dinechin2000exn}.
+
 In both of these two previous cases, performance \emph{can} be a problem. In
 the latter, a slow unwinding directly impacts the overall program performance,
 particularly if a lot of exceptions are thrown and caught far away in their
diff --git a/shared/report.bib b/shared/report.bib
index ec00f11..020492a 100644
--- a/shared/report.bib
+++ b/shared/report.bib
@@ -32,3 +32,21 @@
   year={2011}
 }
 
+@article{dinechin2000exn,
+    title={C++ exception handling},
+    author={De Dinechin, Christophe},
+    journal={IEEE Concurrency},
+    volume={8},
+    number={4},
+    pages={72--79},
+    year={2000},
+    publisher={IEEE}
+}
+
+@online{niditoexn,
+    title={Exceptions in C with Longjmp and Setjmp},
+    author={Nidito, Francesco},
+    url={https://www.di.unipi.it/~nids/docs/longjump_try_trow_catch.html},
+    urldate={2018-08-04}
+}
+