This mostly affects x86. Previously, we threw away the write of the return
address to the stack when identifying calls for macaw-x86. This was partly for
hygiene and partly to support the "addresses written to memory are function
pointers" heuristic. Treating the return address as a potential function
pointer breaks function identification, so that is important.
The problem comes in the translation of macaw into crucible - we never write the
return address to the stack, but returns still read the return address from the
stack. If it wasn't written in the first place, this leads to a read
from (potentially) uninitialized memory, which causes errors in the symbolic
simulator. There are two solutions:
1. Make returns not read from the stack
2. Keep the write of the return address to the stack
Solution 1 is a problem, as we have a data dependency on the read. Eliding it
breaks Crucible generation later and produces an invalid CFG.
Solution 2 works well. The implementation is actually simple. We can keep
identifyCall the same for x86 and just construct the basic block not from the
return value but from the original list of statements (unaltered). We do need
to have identifyCall still give us the reduced statement list, which we use for
identifying possible function pointers written onto the stack (but not the
return address, which we do not want to treat as a function pointer).
This update renames many of the declarations exported by
Data.Macaw.Memory so that we have more consistent names.
The majority of the existing names are now exported with DEPRECATION
warnings. Some of the symbol declarations that were not used by the
Memory datatype have been moved to other modules.
The minor version of macaw-base has been incremented.
This should cut down on the number of proxies/explicit type arguments
needed when dealing with these types.
Awkwardly, ArchTermStmt isn't injective, because PPC32 and PPC64 happen
to use exactly the same type. We could add an argument to that type and
then all the families could be injective.
The pretty-printer for Stmts takes a pretty-printer function as an
argument. This used when a Stmt stores an offset from the beginning of a
block can, but we don't have information about that block internally in
the Stmt.
An ArchState Stmt stores an ArchMemAddr, which is independent of the
block it's in. Previously we were treating the ArchMemAddr as an offset
and passing it to the pretty-printer function for offsets; in practice
this means most of them were printed as values about twice as big as
they were supposed to be.
