75 lines
3.3 KiB
OCaml
75 lines
3.3 KiB
OCaml
(**************************************************************************)
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(* *)
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(* OCaml *)
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(* *)
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(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
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(* Mark Shinwell, Jane Street Europe *)
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(* *)
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(* Copyright 2015 Institut National de Recherche en Informatique et *)
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(* en Automatique. *)
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(* *)
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(* All rights reserved. This file is distributed under the terms of *)
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(* the GNU Lesser General Public License version 2.1, with the *)
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(* special exception on linking described in the file LICENSE. *)
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(* *)
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(**************************************************************************)
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module type S = sig
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(* The distance between two instructions, in arbitrary units (typically
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the natural word size of instructions). *)
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type distance = int
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module Cond_branch : sig
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(* The various types of conditional branches for a given target that
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may require relaxation. *)
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type t
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(* All values of type [t] that the emitter may produce. *)
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val all : t list
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(* If [max_displacement branch] is [n] then [branch] is assumed to
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reach any address in the range [pc - n, pc + n] (inclusive), after
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the [pc] of the branch has been adjusted by [offset_pc_at_branch]
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(see below). *)
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val max_displacement : t -> distance
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(* Which variety of conditional branch may be produced by the emitter for a
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given instruction description. For the moment we assume that only one
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such variety per instruction description is needed.
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N.B. The only instructions supported are the following:
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- Lop (Ialloc _)
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- Lop (Iintop Icheckbound)
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- Lop (Iintop_imm (Icheckbound, _))
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- Lop (Ispecific _)
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- Lcondbranch (_, _)
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- Lcondbranch3 (_, _, _)
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[classify_instr] is expected to return [None] when called on any
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instruction not in this list. *)
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val classify_instr : Linear.instruction_desc -> t option
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end
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(* The value to be added to the program counter (in [distance] units)
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when it is at a branch instruction, prior to calculating the distance
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to a branch target. *)
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val offset_pc_at_branch : distance
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(* The maximum size of a given instruction. *)
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val instr_size : Linear.instruction_desc -> distance
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(* Insertion of target-specific code to relax operations that cannot be
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relaxed generically. It is assumed that these rewrites do not change
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the size of out-of-line code (cf. branch_relaxation.mli). *)
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val relax_allocation
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: num_bytes:int
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-> dbginfo:Debuginfo.alloc_dbginfo
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-> Linear.instruction_desc
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val relax_intop_checkbound
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: unit
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-> Linear.instruction_desc
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val relax_intop_imm_checkbound
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: bound:int
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-> Linear.instruction_desc
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val relax_specific_op : Arch.specific_operation -> Linear.instruction_desc
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end
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