package ocaml-base-compiler

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Assign numerical offsets, within closure blocks, for code pointers and environment entries.

type result = private {
  1. function_offsets : int Closure_id.Map.t;
  2. free_variable_offsets : int Var_within_closure.Map.t;
val compute : Flambda.program -> result
val compute_reexported_offsets : Flambda.program -> current_unit_offset_fun:int Closure_id.Map.t -> current_unit_offset_fv:int Var_within_closure.Map.t -> imported_units_offset_fun:int Closure_id.Map.t -> imported_units_offset_fv:int Var_within_closure.Map.t -> int Closure_id.Map.t * int Var_within_closure.Map.t

If compilation unit C references B, which contains functions inlined from another compilation unit A, then we may need to know the layout of closures inside (or constructed by code inside) a.cmx in order to compile c.cmx. Unfortunately a.cmx is permitted to be absent during such compilation; c.cmx will be compiled using just b.cmx. As such, when building the .cmx export information for a given compilation unit, we also include information about the layout of any closures that it depends on from other compilation units. This means that when situations as just describe arise, we always have access to the necessary closure offsets.