65 lines
3.0 KiB
OCaml
65 lines
3.0 KiB
OCaml
(***********************************************************************)
|
|
(* *)
|
|
(* OCaml *)
|
|
(* *)
|
|
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
|
|
(* Mark Shinwell, Jane Street Europe *)
|
|
(* *)
|
|
(* Copyright 2015 Institut National de Recherche en Informatique et *)
|
|
(* en Automatique. All rights reserved. This file is distributed *)
|
|
(* under the terms of the Q Public License version 1.0. *)
|
|
(* *)
|
|
(***********************************************************************)
|
|
|
|
module type S = sig
|
|
(* The distance between two instructions, in arbitrary units (typically
|
|
the natural word size of instructions). *)
|
|
type distance = int
|
|
|
|
module Cond_branch : sig
|
|
(* The various types of conditional branches for a given target that
|
|
may require relaxation. *)
|
|
type t
|
|
|
|
(* All values of type [t] that the emitter may produce. *)
|
|
val all : t list
|
|
|
|
(* If [max_displacement branch] is [n] then [branch] is assumed to
|
|
reach any address in the range [pc - n, pc + n] (inclusive), after
|
|
the [pc] of the branch has been adjusted by [offset_pc_at_branch]
|
|
(see below). *)
|
|
val max_displacement : t -> distance
|
|
|
|
(* Which variety of conditional branch may be produced by the emitter for a
|
|
given instruction description. For the moment we assume that only one
|
|
such variety per instruction description is needed.
|
|
|
|
N.B. The only instructions supported are the following:
|
|
- Lop (Ialloc _)
|
|
- Lop (Iintop Icheckbound)
|
|
- Lop (Iintop_imm (Icheckbound, _))
|
|
- Lop (Ispecific _)
|
|
- Lcondbranch (_, _)
|
|
- Lcondbranch3 (_, _, _)
|
|
[classify_instr] is expected to return [None] when called on any
|
|
instruction not in this list. *)
|
|
val classify_instr : Linearize.instruction_desc -> t option
|
|
end
|
|
|
|
(* The value to be added to the program counter (in [distance] units)
|
|
when it is at a branch instruction, prior to calculating the distance
|
|
to a branch target. *)
|
|
val offset_pc_at_branch : distance
|
|
|
|
(* The maximum size of a given instruction. *)
|
|
val instr_size : Linearize.instruction_desc -> distance
|
|
|
|
(* Insertion of target-specific code to relax operations that cannot be
|
|
relaxed generically. It is assumed that these rewrites do not change
|
|
the size of out-of-line code (cf. branch_relaxation.mli). *)
|
|
val relax_allocation : num_words:int -> Linearize.instruction_desc
|
|
val relax_intop_checkbound : unit -> Linearize.instruction_desc
|
|
val relax_intop_imm_checkbound : bound:int -> Linearize.instruction_desc
|
|
val relax_specific_op : Arch.specific_operation -> Linearize.instruction_desc
|
|
end
|