tobast/phd-thesis
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Foundations: finish definitions

Browse source
This commit is contained in:
Théophile Bastian 2024-02-14 18:03:38 +01:00
parent baebd14466
commit 5f8ff8599b
1 changed files with 17 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
manuscrit/20_foundations/20_code_analyzers.tex
View file

@ -435,6 +435,8 @@ straight-line code linked to other basic blocks to reflect control flow. We
define this notion here formally, to use it soundly in the following chapters
of this manuscript.
\newpage % FIXME
\begin{notation}
For the purposes of this section,
\begin{itemize}
@ -459,7 +461,21 @@ of this manuscript.
\end{notation}
\begin{definition}[Basic block decomposition]
\todo{}
Consider a sequence of assembly code $A$. We note the $J_A$ the set of jump
sites of $A$, $F_A$ the set of flow-altering instructions of $A$. As each
element of those sets is the address of an instruction, we note $F^+_A$ the
set of addresses of instructions \emph{directly following} an instruction
from $F_A$ ---~note that, as instructions may be longer than one byte, it
is not sufficient to increase by 1 each address from $F_A$.
We note $S_A = J_A \cup F^+_A$. We split the instructions from $A$ into
$BB(A)$, the set of segments that begin either at the beginning of $A$, or
at instructions from $S_A$ ---~less formally, we split $A$ at each point
from $S_A$, including each boundary in the following segment.
The members of $BB(A)$ are the \emph{basic blocks} of $A$, and are segments
of code which, by construction, will always be executed as straight-line
code, and whose execution will always begin from their first instruction.
\end{definition}
\begin{remark}