mirror of
https://github.com/GaloisInc/macaw.git
synced 2024-12-26 23:52:48 +03:00
71 lines
3.0 KiB
ReStructuredText
71 lines
3.0 KiB
ReStructuredText
Overview
|
|
========
|
|
|
|
This repository implements some shared code that can be re-used by multiple
|
|
architecture-specific backends to bridge the semantics defined in the semmc
|
|
repository [SemMC]_ to macaw [macaw]_. The semantics in SemMC are defined in
|
|
terms of the ExprBuilder [EB]_ IR from Crucible/What4. The code in this library
|
|
translates those ExprBuilder-based formulas into a Haskell function that
|
|
generates macaw IR expressions (see the ``genExecInstruction`` function in
|
|
``Data.Macaw.SemMC.TH``). This repository contains code shared between all
|
|
architectures; the intent is that each architecture will also define
|
|
architecture-specific operations that are taken as an input to this library.
|
|
|
|
Architecture-Specific Backends
|
|
==============================
|
|
|
|
See macaw-ppc as an example for what is required in an architecture-specific
|
|
backend. At a high level, the required steps are:
|
|
|
|
1. Define an architecture-specific register type
|
|
2. Define architecture-specific functions and statements
|
|
3. Define a transformation from architecture-specific locations into TH expressions
|
|
4. Define a function to translate ExprBuilder ``NonceApp``s into TH expressions
|
|
5. Define a function translate ExprBuilder ``App``s into TH expressions
|
|
6. Define a function to translate *instructions* into TH expressions
|
|
|
|
Architecture-Specific Register Type
|
|
-----------------------------------
|
|
|
|
Architecture-Specific Functions
|
|
-------------------------------
|
|
|
|
Translating Architecture-Specific Locations
|
|
-------------------------------------------
|
|
|
|
Translating ``NonceApp``
|
|
------------------------
|
|
|
|
This translator is for translating architecture-specific uninterpreted
|
|
functions, which are represented using ``NonceApp`` in ExprBuilder. These
|
|
will be most often translated into architecture-specific functions, but may also
|
|
require architecture-specific statements to represent side effects (including
|
|
exceptions). This is also where all floating point operations are translated,
|
|
as there are no floating point operations in macaw.
|
|
|
|
Translating ``App``
|
|
-------------------
|
|
|
|
Very few ``App`` constructors in ExprBuilder require custom translation. This
|
|
is primarily intended to translate division-type operations into
|
|
architecture-specific functions, as there are no division operations defined in
|
|
macaw.
|
|
|
|
Translating Instructions
|
|
------------------------
|
|
|
|
The final specialized matcher is for doing direct translations of instructions
|
|
into architecture-specific statements. This is meant for instructions for which
|
|
we cannot express semantics in the ExprBuilder IR due to special side effects.
|
|
Often, trap and system call-type instructions fall into this category.
|
|
|
|
Note that this function is specified by TH ``Name`` instead of as a value-level
|
|
function; this is required, as its type signature refers to an
|
|
architecture-specific type, which we cannot mention in this shared library
|
|
without incurring undesired dependencies.
|
|
|
|
|
|
.. [SemMC] https://github.com/GaloisInc/semmc
|
|
.. [macaw] https://github.com/GaloisInc/macaw
|
|
.. [EB] https://github.com/GaloisInc/crucible/blob/master/what4/src/What4/Expr/Builder.hs
|