Introduce LegacySegregateStackAccessesPipe
This commit restructures the SegregateStackAccesses pass and
SegregateStackAccessesPipe so that they can have 2 modes of operations:
1. Legacy, with the same behavior as the old version, injecting local
variables as custom llvm::Functions representing opcodes, such as
LocalVariable, AddressOf, StackFrameAllocator, and CallStackArguments
allocator.
2. Non-legacy, that is meant to operate with the new LocalVariableHelper
to inject local variables as regular alloca instructions, with
additional metadata to discriminate among them.
This commit renames the old SegregateStackAccessesPipe to
LegacySegregateStackAccessesPipe.
It then re-uses the old SegregateStackAccessesPipe name for a new pipe,
meant to work in non-legacy mode.
The pipeline definition YAML file is updated to keep using the legacy
version for now.
For now the implementation is still the same.
Change company name to "rev.ng Labs Srl" in all license headers
to reflect changed company name and legal status
Add missing license headers to files that didn't have one
Pietro Fezzardi