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