Perform the ALAP Variable Declaration process.
The process is structured in the following stages:
- We start by collecting all the `Variable`s that need to be assigned in
a `ASTNode`.
- We build a `GenericGraph` where each `ASTNode` is connected with its
child nodes, and also its immediate successor.
- We perform a walk in post order over this graph, and for each
`ASTNode` we decide if the current node could be the ALAP location
where we can declare the `Variable`, i.e., where we dominate all its
uses.
Simplification includes dropping dependencies onto
`FunctionMetadataCachePass` and `LoadModelWrapperPass`, as well
as removing "StructName" logic outright.
Perform a complete rewrite of the `SwitchNode` tiling routine.
The tiling now works in the following way:
- When encountering a node which will produce a `SwitchNode` (either a
standard `switch` or a dispatcher `switch`), we look for the following
situations:
1) We have a node, a successor (case) of the `switch`, which in turn
is the successor of all the other successors (cases) of the
`switch`.
2) We have a node, not a successor (case) of the `switch`, which is
the successor of all the successors (cases) of the `switch`.
- If we find such candidate node, this node will be the fallthrough of
the `switch`. In addition, depending on whether the `switch` dominates
the candidate fallthrough, we can incorporate it as the immediate
successor of the `SwitchNode` we are building.
- There is currently an exception to the above, due to how we currently
handle weaved `switch`es. In such cases, we mandate that the weaved
`switch` is nested inside the main corresponding `switch`. For this
reason, we have a special casing handling the "all inlined but one"
situation in the new code, while this part could in theory be merged
in the common criterion below, at the cost of dropping the invariant
of the nesting of weaved switch`es.
Simplify `switch` cases that are simplified away during the dispatcher
`switch` inlining beautify.
Usually, we can simplify ast nodes by replacing them with `nullptr`s,
but due to how the `switch` cases work, we need to handle them in a
custom way.
This lets us drop the repeated alignment calculations at
the "leaves" of the conversion. Since new distributor already
provides the necessary information, we can just grab it from
there.
Before this, padding was just handled as a part of the size, but that
made it unnecessarily hard to work with. Now, everything padding-related
is extremely explicit.
A class or a struct type A can be a forward declaration and refer
to another type B in PDB, so we need to follow the references.
We pre-create type for B, when we face type A, and then, when we
visit type B, we populate the fields for the model::type we
pre-created.
In addition, this patch fixes some minor/side bugs:
- Handle SHORT/Int16Short simple type
- Do not delete model::Function if Prototype is invalid.
Alessandro Di Federico