Module Flambda2_simplify.Lifted_cont_params
New parameters for lifted continuations
While lifting continuations, new parameters have to be introduced to replace variables that are in the lexical scope at the original location of the continuation being lifted, but are not at its destination.
The tricky part with these parameters is to compute the adequate new arguments to apply at each call site. In simple situations, these new params are simply renamed versions of the original variables, and the arguments are the original variables. However, that stops being true if a call site is in fact in another continuation that is also being lifted, in which case the arg to provide is actually the new name of the new param in that last continuation.
This is reasonably solved by mapping all new params to the original variable (i.e. the one that was in the lexical scope), and storing that mapping for each continuation. Then, for a given call site, for each new parameter, we can lookup the original variable that introduced it, and then look into the stack of parent continuations to see which one first defines a new (lifting) param that maps back to the same original variable.
This type represents all of the new params for one lifted continuation. These added parameters are internally indexed by a unique identifier: when an individual new param is first created/added to a value of type t, it is given a fresh identifier.
val print :
Stdlib.Format.formatter ->
Flambda2_simplify.Lifted_cont_params.t ->
unitPrint function.
val empty : Flambda2_simplify.Lifted_cont_params.tThe empty set of lifted cont params.
val is_empty : Flambda2_simplify.Lifted_cont_params.t -> boolIs the set of new params empty ?
val length : Flambda2_simplify.Lifted_cont_params.t -> intNumber of new params.
val new_param :
Flambda2_simplify.Lifted_cont_params.t ->
replay_history:Flambda2_simplify.Replay_history.t ->
Flambda2_bound_identifiers.Bound_parameter.t ->
Flambda2_simplify.Lifted_cont_params.tAdd a new parameter
val rename :
Flambda2_simplify.Lifted_cont_params.t ->
Flambda2_simplify.Lifted_cont_params.t * Flambda2_nominal.Renaming.tRename all new parameters, and returns the corresponding renaming.
val args :
callee_lifted_params:Flambda2_simplify.Lifted_cont_params.t ->
caller_stack_lifted_params:Flambda2_simplify.Lifted_cont_params.t list ->
Flambda2_term_basics.Simple.t listThis function computes all adequate args for a given callsite. This takes the lifted cont params of the continuation being called, as well as the stack of the lifted params for all parent continuations at the callsite.
val bound_parameters :
Flambda2_simplify.Lifted_cont_params.t ->
Flambda2_bound_identifiers.Bound_parameters.tReturns the bound parameters for a given set of new params. The parameters returned by this function are in the same order as the arguments returned by the args function.
val fold :
init:'a ->
f:(Flambda2_bound_identifiers.Bound_parameter.t -> 'a -> 'a) ->
Flambda2_simplify.Lifted_cont_params.t ->
'aFold over all of the new parameters. The order in which the parameters are iterated through is **not** specified.