This commit fixes a bug due to interacting behaviors between
MarkForSerialization, AddSCEVBarrierPass, and the emission in C of calls
to revng_init_local_sp.
These interacting behaviors caused the following quirks:
- At the beginning of Functions that contained a call to
`revng_init_local_sp()`, that call was actually emitted twice.
The first time was due to the actual call to `revng_init_local_sp()`,
while the second was due to the first call being wrapped from a call
to `revng_scev_barrier_*`.
Now we properly emit only one call.
- The original call to `revng_init_local_sp()` was supposed to generate
a local variable, to be used in various places across the function.
However, due to the fact that the call was not properly labeled by
MarkForSerialization, there was no local variable, causing calls to
`revng_init_local_sp()` to be scattered around the body of the
functions, follwed by various arithmetic operations.
This behavior has been fixed as well, and we now emit the local
variable correctly.
This commit introduces a new LatticeElement for the
MarkAnalysis::Analysis MonotoneFramework.
Before this it used a IntersectionMonotoneSet.
This commit extends the set transforming it into a map, that holds the
set of Instructions with side-effects that taint each pending
instruction.
This is not used yet. The behavior is identical to the old one.
It will be used in future commits to prevent serialization when
possible, to increase the quality of emitted C code, thanks to the fact
that serializing less instructions means less local variables in C.
This commit is a hack, that removes an assertion on NDuplicates.
For now we can remove this check, because we declare all the local
variables at the beginning of the function body.
Whenever we start emitting the declarations of local variables
as-late-as-possible, we'll need to take care of this.
With this commit `ExtractValueInst`s are handled so that they don't have
side effects.
This significantly improves the quality of the decompiled output,
preventing the forced serialization of all the extraction of struct
fields after calls to function that return structs, except for when it's
really needed.
Before this commit, the C statements before an IfNode or a SwitchNode
were not guaranteed to be emitted if they were not involved in the
computation of the branch condition.
This commit fixes this problem.
Removed the computation of the information contained in the
`NDuplicates` prevously done in the `MarkForSerialization` pass, since
the information is now precomputed in the `RestructureCFG` pass and
exposed with a dedicated method.
Moved a lot of passes that apply optimizations on the AST in the
decompilation pass.
All the optimization functions are now in a dedicated file
(`CDecompilerBeautify.cpp`) and the only function used as interface with
the `CDecompilerAction` pass is the `beautifyAST` function.
This means that now the simplifications will be applied on the already
flattened AST.
Some basic transformations have been left in the `RestructureCFG` pass,
to avoid having an AST of poor quality as output of the pass.
Pietro Fezzardi