If we find values to be used outside their scope, we need to always
mark them for assignment, so that they have a dedicated variable that
is declared in the right scope. To do this we:
1. Export the logic that decides if a value needs a top-scope variable
in a public header, to be used by both `VariableScopeAnalysis` and
`MarkAssignments`.
2. Add the `HasUsesOutsideBB` reason for assignment markers
Now that the late stage of the decompilation pipeline is managed with
revng-pipeline, and we have a standalone tool for decompilation, we
have no need to use LLVM passes anymore for those stages.
This commit also renames the directories to avoid the confusing Pass
suffix, not what LLVM passes are gone.
This commit replace the old CBackendPass with a standalone tool:
revng-decompile.
This pass at the moment runs the three stages of decompilation:
- CFG restructuring
- Beautify GHAST
- C Code generation
Alvise de Faveri