This fixes an error introduced in the ghc-8.8 updates. The error caused
macaw-x86 to throw an uncaught error when decoding certain instructions, when it
should have instead caught the error and reported a decode failure as a block
terminator.
This commit updates macaw-refinement to work with the latest macaw/crucible and makes a few improvements along the way.
The major changes involved in this are:
* Block labels were removed from macaw, so we had to come up with an alternative approach to making synthetic blocks to represent dispatch resolved by macaw-refinement that is not really a jump table. We considered adding a new terminator that encoded "computed IP-based dispatch", but there was concern about the impact on client code. Instead, we added a field to the `DiscoveryFunInfo` that records "external" resolutions to indirect control flow (e.g., as by an SMT solver in macaw-refinement). The hook by which we feed SMT-based resolutions back into macaw was modified accordingly (`addDiscoveredFunctionBlockTargets`).
* Solver invocation changed to allow solver selection and parallel solver application.
* Logging is now done via the `lumberjack` library.
* macaw-symbolic now uses the "external" resolutions in `DiscoveryFunInfo` while building crucible CFGs.
* The path creation code in macaw-refinement was simplified significantly and the approach to path creation has been documented.
* The run-refinement tool is now more featureful.
* The test suite is a bit more structured and no longer depends on the printed output of the discovery process.
Updates for GHC 8.8
The two main classes of update are related to MonadFail and type alias expansion.
The MonadFail updates introduce explicit MonadFail instances and backward-compatible `fail` implementations under `Monad` for older GHC versions.
The type alias expansion rules changed in GHC 8.8 in a way that breaks the `Simple Lens` idiom; instead, we have to use `Lens'`. Lens started supporting this alias in version 3.8, which was released in 2013.
This change includes necessary submodule updates, as well as the update for the split of what4 into its own repository.
The new registerUse analysis uses a three phase process:
Phase 1 computes invariants about the start state of each block. It
will indicate when registers/stack locations store stack offsets, and
where callee saved registers are stashed. It also memoizes
information about stack reads and writes to simplify later passes.
Phase 2 is a demand analysis that computes which registers and stack
locations must be available to execute the program. It then
propagates those constraints across blocks in the function.
Phase 3 combines the information into a form relevant for function
recovery.
The only real code change required is that simulation failure messages have an
extra argument. The goal with this update is to pull in some fixes to the
solver feature detection for yices in the latest crucible.
The improved string support in Crucible adds a parameter to string reprs; this
change accommodates that. Earlier changes added the necessary support in the
rest of macaw.
This was an artifact of merging macaw-semmc into macaw. This commit unifies the
two directories. There are some remaining submodules in the old directory:
these are obsolete and will be removed in a separate commit.
This primarily refines the abstract state propagated to branch
pairs. It was needed on the ARM platform to support the IT blocks
with the changes to the Core representation in macaw-base 0.3.6.
This also includes a few simplifications added and comment
improvements.
The llvm memory model was extended with better diagnostics and configurable
handling of undefined behavior. macaw-symbolic uses no undefined behavior
checking, as those operations are only undefined in C.
