Skip to content
GitLab
Menu
Projects
Groups
Snippets
Loading...
Help
Help
Support
Community forum
Keyboard shortcuts
?
Submit feedback
Contribute to GitLab
Sign in
Toggle navigation
Menu
Open sidebar
Benoit Viguier
coqveriftweetnacl
Commits
054d33a2
Commit
054d33a2
authored
Oct 01, 2020
by
benoit
Browse files
add section lesson learned
parent
68f0e50f
Changes
2
Show whitespace changes
Inline
Sidebyside
paper/Makefile
View file @
054d33a2
...
...
@@ 34,3 +34,8 @@ clean:

rm
tweetverif.blg

rm
tweetverif.brf
make
C
csfsupplementary clean
spell
:
@
for
f
in
$(SOURCES)
;
do
\
aspell
t
c
$$
f
;
\
done
paper/conclusion.tex
View file @
054d33a2
...
...
@@ 15,7 +15,7 @@ In our case we rely on:
used by Coq must be consistent in order to trust the proofs. As an axiom,
we assume that the functional extensionality is also consistent with that logic.
$$
\forall
x, f
(
x
)
=
g
(
x
)
\implies
f
=
g
$$
\begin{lstlisting}
[language=Coq,belowskip=0.25
\baselineskip
]
\begin{lstlisting}
[language=Coq,belowskip=0.25
\baselineskip
]
Lemma f
_
ext: forall (A B:Type),
forall (f g: A > B),
(forall x, f(x) = g(x)) > f = g.
...
...
@@ 91,8 +91,25 @@ above will soon be integrated in a new version of the library.
% As a result we do not believe the metric personmonth to be
% a good representation of the verification effort.
\subheading
{
Lessons learned.
}
\todo
{
Write something about VST etc.
}
\subheading
{
Lessons learned.
}
The effort to verify an existing code base is
significantly harder than synthesizing a proven by construction piece of software.
This difficulty is additionally increased by not having the freedom to modify
the original code, and by the lowlevel optimization applied in it.
This often requires to write functions that mimic the behavior of the C
code before proving multilevel equivalences to reach the desired level of specifications.
VST provides on one hand a large set of lemmas, and on the second hand tactics to use them.
If a lemma is directly applied, it generates a multiple subgoals with a large set of dependent existential variables.
The tactics provided try to resolve those, and aim to simplify the workload of its user.
In an ideal world, the user does not need to know the lemmas applied under the hood and can just rely on those tactics.
Unfortunately, there were instances where those were not helping
% (\eg applying unnecessary substitutions, unfolding, exploding the size of our current goal; or simply failing),
at such moment, it was necessary to look into the VST code base and search for the right lemma.
Furthermore, the VST being an academic software, it is very hard to work with a tool
without being involved in the development loop. Additionally newer versions often broke
some of our proofs and it was often needed to adapt to the changes. That being said,
as we reported our bugs and struggles to the development team, the toolchain improved a lot.
\subheading
{
Extending our work.
}
The highlevel definition (
\sref
{
sec:maths
}
) can easily be ported to any
...
...
Write
Preview
Markdown
is supported
0%
Try again
or
attach a new file
.
Attach a file
Cancel
You are about to add
0
people
to the discussion. Proceed with caution.
Finish editing this message first!
Cancel
Please
register
or
sign in
to comment