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Add open Expr in I

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Théophile Bastian 2018-08-19 14:10:30 +02:00
parent 700c823646
commit ef6d68b36e
2 changed files with 12 additions and 7 deletions
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18
report/report.tex
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@ -398,9 +398,9 @@ parse the relevant FDE from its start, until it finds the row it was seeking.
We will now define semantics covering most of the operations used for FDEs
described in the DWARF standard~\cite{dwarf5std}, such as seen in
Listing~\ref{lst:ex1_dwraw}, with the exception of DWARF expressions. These are
not exhaustively treated because they form a rich language and would take a lot
of time and space to formalize, and in the meantime are only seldom used (see
the DWARF statistics regarding this).
not treated here, because they form a rich language and would take a lot
of time and space to formalize, while in the meantime being seldom used --~see
Section~\ref{ssec:instr_cov}.
These semantics are defined with respect to the well-formalized C language, and
are passing through an intermediary language. The DWARF language can read the
@ -489,6 +489,7 @@ Its grammar is as follows:
\values &::= \bot & \text{Values: undefined,}\\
&\quad\vert~\valaddr{\spexpr} & \text{at address $x$},\\
&\quad\vert~\valval{\spexpr} & \text{of value $x$} \\
&\quad\vert~\valexpr{??} & \text{of expression $x$, see in text} \\
\spexpr &::= \regs \times \mathbb{Z}
& \text{A ``simple'' expression $\reg{reg} + \textit{offset}$} \\
\end{align*}
@ -510,7 +511,9 @@ value $x$, $x$ being here a simple expression consisting of $\reg{reg} +
\textit{offset}$. The CFA is considered a simple register here. For instance,
to define $\reg{rax}$ to the value contained in memory 16 bytes below the CFA,
we would have $\reg{rax} \mapsto \valaddr{\reg{CFA}, -16}$, since the stack
grows downwards.
grows downwards. We also leave open the possibility to extend the language with
DWARF expressions support as $\valexpr{}$, although we \emph{do not} specify
them here.
\subsection{Target language: a C function body}
@ -632,9 +635,10 @@ we omit those two operations, we can plainly remove the stack.
\subsection{From $\intermedlang$ to C}
\textit{This only defines the semantics, with respect to standard C, of DWARF
as interpreted by \ehelf\@. The actual DWARF to C compiler is not implemented
this way.}
\emph{The C code provided thereafter is a correct but inefficient reference
implementation, which is only provided for formalization, to specify DWARF
\wrt{} C. In particular, the actual compiler is \emph{not} implemented this
way.}
\medskip

1
shared/specific.sty
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@ -24,6 +24,7 @@
\newcommand{\valaddr}[1]{\operatorname{Addr}\left(#1\right)}
\newcommand{\valval}[1]{\operatorname{Val}\left(#1\right)}
\newcommand{\valexpr}[1]{\operatorname{Expr}\left(#1\right)}
\newcommand{\intermedlang}{\mathcal{I}}