%% -*- erlang-indent-level: 2 -*-
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% @doc	This is the HiPE compiler's main "loop".
%%
%% <h3>Purpose</h3>
%%
%% <p> This module provides code which compiles a single Erlang
%% function, represented as linear ICode all the way down to a linear
%% native code representation (which depends on the 'hipe_target_arch'
%% global variable). </p>
%%
%% @end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%=====================================================================

-module(hipe_main).
-export([compile_icode/4]).

%%=====================================================================

-ifndef(DEBUG).
-define(DEBUG,1).
-endif.

-define(HIPE_INSTRUMENT_COMPILER, true). %% Turn on instrumentation.

-include("hipe.hrl").
-include("../icode/hipe_icode.hrl").
%%-include("../rtl/hipe_rtl.hrl").

%%=====================================================================

-type comp_icode_ret() :: {'native',hipe_architecture(),{'unprofiled',_}}
			| {'rtl',tuple()} | {'llvm_binary',term()}.

%%=====================================================================

%% @spec compile_icode(MFA::mfa(),
%%                     LinearIcode::icode(),
%%                     CompilerOptions::comp_options(),
%%		       CompServers::#comp_servers()) ->
%%          {native,Platform,{unprofiled,NativeCode}} | {rtl,RTLCode}
%%
%% @doc Compiles the Icode (in linear form) of a single MFA down to
%% native code for the platform of the target architecture.
%% CompilerOptions influence the steps of this compilation process.
%%
%% <p> In particular, the compiler option '<code>to_rtl</code>' stops
%% compilation after translation to RTL (in which case RTL code is
%% generated). The compiler options must have already been expanded
%% (cf. `<a href="hipe.html">hipe:expand_options</a>'). </p>

-spec compile_icode(mfa(), icode(), comp_options(), #comp_servers{}) ->
	 comp_icode_ret().

compile_icode(MFA, LinearIcode, Options, Servers) ->
  compile_icode(MFA, LinearIcode, Options, Servers, get(hipe_debug)).

%%--------------------------------------------------------------------
%%
%% The following constraints apply to the passes on Icode:
%% 
%% 1. The no_comment pass must be done on linear form;
%%
%% 2. linear_to_cfg, which turns linear form into a CFG, must be
%%    performed before any of the passes on CFG form;
%%
%% 3. handle_exceptions must be performed before icode_ssa;
%%
%% 4. split_arith should be performed after icode_ssa for
%%    effectiveness reasons (and perhaps to work at all);
%%
%% 5. remove_trivial_bbs should be performed last to tidy up the CFG.
%%
%%---------------------------------------------------------------------

compile_icode(MFA, LinearIcode0, Options, Servers, DebugState) ->  
  %% Set up gensym with the right ranges for this function.
  {LMin,LMax} = hipe_icode:icode_label_range(LinearIcode0),
  hipe_gensym:set_label_range(icode, LMin, LMax+1),
  {VMin,VMax} = hipe_icode:icode_var_range(LinearIcode0),
  hipe_gensym:set_var_range(icode, VMin, VMax+1),
  %%hipe_icode_pp:pp(LinearIcode0),
  ?opt_start_timer("Icode"),
  LinearIcode1 = icode_no_comment(LinearIcode0, Options),
  IcodeCfg0 = icode_linear_to_cfg(LinearIcode1, Options),
  %% hipe_icode_cfg:pp(IcodeCfg0),
  IcodeCfg1 = icode_handle_exceptions(IcodeCfg0, MFA, Options),
  IcodeCfg3 = icode_inline_bifs(IcodeCfg1, Options),
  pp(IcodeCfg3, MFA, icode, pp_icode, Options, Servers),
  IcodeCfg4 = icode_ssa(IcodeCfg3, MFA, Options, Servers),
  IcodeCfg5 = icode_split_arith(IcodeCfg4, MFA, Options),
  pp(IcodeCfg5, MFA, icode, pp_icode_split_arith, Options, Servers),
  IcodeCfg6 = icode_heap_test(IcodeCfg5, Options),
  IcodeCfg7 = icode_remove_trivial_bbs(IcodeCfg6, Options),
  pp(IcodeCfg7, MFA, icode, pp_opt_icode, Options, Servers),
  pp(IcodeCfg7, MFA, icode_liveness, pp_icode_liveness, Options, Servers),
  FinalIcode = hipe_icode_cfg:cfg_to_linear(IcodeCfg7),
  ?opt_stop_timer("Icode"),
  {LinearRTL, Roots} = ?option_time(icode_to_rtl(MFA, FinalIcode, Options, Servers),
          "RTL", Options),
  case proplists:get_bool(to_rtl, Options) of
    false ->
      case proplists:get_bool(to_llvm, Options) of
        false ->
          rtl_to_native(MFA, LinearRTL, Options, DebugState);
        true ->
          %% The LLVM backend returns binary code, unlike the rest of the HiPE
          %% backends which return native assembly.
          rtl_to_llvm_to_binary(MFA, LinearRTL, Roots, Options, DebugState)
      end;
    true ->
      put(hipe_debug, DebugState),
      {rtl, LinearRTL}
  end.

%%----------------------------------------------------------------
%%
%% Icode passes
%%
%%----------------------------------------------------------------

icode_no_comment(LinearIcode, Options) ->
  case proplists:get_bool(remove_comments, Options) of
    true ->
      ?option_time(hipe_icode:strip_comments(LinearIcode),
		   "Icode remove comments", Options);
    _ ->
      LinearIcode
  end.

icode_linear_to_cfg(LinearIcode, Options) ->
  ?option_time(hipe_icode_cfg:linear_to_cfg(LinearIcode),
	       "transform linear Icode to CFG", Options).

icode_ssa_binary_pass(IcodeSSA, Options) ->
  case proplists:get_bool(binary_opt, Options) of
    true ->
      ?option_time(hipe_icode_bincomp:cfg(IcodeSSA),
		   "Icode binary pass", Options);
    false ->
      IcodeSSA
  end.

icode_handle_exceptions(IcodeCfg, MFA, Options) ->
  debug("Icode fix catches: ~w~n", [MFA], Options),
  ?option_time(hipe_icode_exceptions:fix_catches(IcodeCfg),
	       "Icode fix catches", Options).

icode_inline_bifs(IcodeCfg, Options) ->  
  case proplists:get_bool(icode_inline_bifs, Options) of
    true ->
      ?option_time(hipe_icode_inline_bifs:cfg(IcodeCfg),
		   "Icode inline bifs", Options);
    false ->
      IcodeCfg
  end.

%%---------------------------------------------------------------------

icode_split_arith(IcodeCfg, MFA, Options) ->
  case proplists:get_bool(split_arith, Options) orelse
       proplists:get_bool(split_arith_unsafe, Options) of
    true ->
      ?option_time(hipe_icode_split_arith:cfg(IcodeCfg, MFA, Options),
        	   "Icode split arith", Options);
    false ->
      IcodeCfg
  end.

icode_heap_test(IcodeCfg, Options) ->
  ?option_time(hipe_icode_heap_test:cfg(IcodeCfg),
	       "Icode heap_test", Options).

icode_remove_trivial_bbs(IcodeCfg, Options) ->
  ?option_time(hipe_icode_cfg:remove_trivial_bbs(IcodeCfg),
	       "Icode trivial BB removal", Options).

pp(Cfg, MFA, Level, PrintOption, Options, Servers) ->
  perform_io(pp_fun(Cfg, MFA, get_pp_module(Level), 
		    proplists:get_value(PrintOption, Options)), 
		    Servers#comp_servers.pp_server).

pp_fun(Cfg, MFA, PP, PrintOptionValue) ->
  case PrintOptionValue of
    true ->
      fun() -> PP:pp(Cfg) end;
    {only, Lst} when is_list(Lst) ->
      case lists:member(MFA, Lst) of
	true ->
	  fun() -> PP:pp(Cfg) end;
	false ->
	  no_fun
      end;
    {only, MFA} ->
      fun() -> PP:pp(Cfg) end;
    {file, FileName} ->
      fun() ->
	  {ok, File} = file:open(FileName, [write,append]),
	  PP:pp(File, Cfg),
	  file:close(File)
      end;
    _ ->
      no_fun
  end.

get_pp_module(icode) -> hipe_icode_cfg;
get_pp_module(rtl) -> hipe_rtl_cfg;
get_pp_module(rtl_linear) -> hipe_rtl;
get_pp_module(icode_liveness) -> hipe_icode_liveness;
get_pp_module(rtl_liveness) -> hipe_rtl_liveness.
  
perform_io(no_fun, _) -> ok;
perform_io(Fun, PPServer) when is_pid(PPServer) ->
  PPServer ! {print, Fun},
  ok;
perform_io(Fun, none) ->
  Fun(),
  ok.


%%--------------------------------------------------------------------
%%
%% Icode passes on SSA form. The following constraints are applicable:
%% 
%% 1. ssa_convert must be first and ssa_unconvert last
%% 
%% 2. ssa_dead_code must be run after the other passes
%%
%% 3. The present order was chosen to maximize effectiveness as
%%    ssa_const_prop might make ssa_type_info more effective
%% 
%% 4. ssa_check could be put in between all passes to make sure that
%%    they preserve SSA-ness
%%
%%---------------------------------------------------------------------

icode_ssa(IcodeCfg0, MFA, Options, Servers) ->
  ?opt_start_timer("Icode SSA passes"),
  IcodeSSA0 = icode_ssa_convert(IcodeCfg0, Options),
  pp(IcodeSSA0, MFA, icode, pp_icode_ssa, Options, Servers),
  IcodeSSA1 = icode_ssa_const_prop(IcodeSSA0, Options),
  IcodeSSA2 = icode_ssa_dead_code_elimination(IcodeSSA1, Options),
  IcodeSSA3 = icode_ssa_copy_prop(IcodeSSA2, Options),
  IcodeSSA3a = icode_ssa_binary_pass(IcodeSSA3, Options),
  IcodeSSA4 = icode_ssa_type(IcodeSSA3a, MFA, Options, Servers),
  IcodeSSA5 = icode_ssa_dead_code_elimination(IcodeSSA4, Options),
  IcodeSSA6 = icode_ssa_struct_reuse(IcodeSSA5, Options),
  icode_ssa_check(IcodeSSA6, Options), %% just for sanity
  pp(IcodeSSA6, MFA, icode, pp_icode_ssa, Options, Servers),
  IcodeCfg = icode_ssa_unconvert(IcodeSSA6, Options),
  ?opt_stop_timer("Icode SSA passes"),
  IcodeCfg.

icode_ssa_type(IcodeSSA, MFA, Options, Servers) ->
  case proplists:get_value(icode_type, Options) of
    false -> IcodeSSA;
    undefined -> IcodeSSA;
    true ->
      AnnIcode1 = icode_ssa_type_info(IcodeSSA, MFA, Options, Servers),
      pp(AnnIcode1, MFA, icode, pp_typed_icode, Options, Servers),
      AnnIcode2 = 
	case proplists:get_bool(inline_fp, Options) of
	  true -> hipe_icode_fp:cfg(AnnIcode1);
	  false -> AnnIcode1
	end,
      AnnIcode3 = icode_range_analysis(AnnIcode2, MFA, Options, Servers),
      AnnIcode4 = icode_eliminate_safe_calls(AnnIcode3, Options),
      pp(AnnIcode4, MFA, icode, pp_range_icode, Options, Servers),
      hipe_icode_type:unannotate_cfg(AnnIcode4)
  end.

icode_ssa_convert(IcodeCfg, Options) ->
  ?option_time(hipe_icode_ssa:convert(IcodeCfg),
	       "Icode SSA conversion", Options).

icode_ssa_const_prop(IcodeSSA, Options) ->
  case proplists:get_bool(icode_ssa_const_prop, Options) of
    true ->
      Tmp = ?option_time(hipe_icode_ssa_const_prop:propagate(IcodeSSA),
		   "Icode SSA sparse conditional constant propagation", Options),
      ?option_time(hipe_icode_ssa:remove_dead_code(Tmp),
		   "Icode SSA dead code elimination pass 1", Options);
    false ->
      IcodeSSA
  end.

icode_ssa_copy_prop(IcodeSSA, Options) ->
  case proplists:get_bool(icode_ssa_copy_prop, Options) of
    true ->
      ?option_time(hipe_icode_ssa_copy_prop:cfg(IcodeSSA),
		   "Icode SSA copy propagation", Options);
    false ->
      IcodeSSA
  end.

icode_ssa_struct_reuse(IcodeSSA, Options) ->
  case proplists:get_value(icode_ssa_struct_reuse, Options) of
    true ->
      ?option_time(hipe_icode_ssa_struct_reuse:struct_reuse(IcodeSSA),
		   "Icode SSA structure reuse", Options);
    _ -> 
      IcodeSSA
  end.

icode_ssa_type_info(IcodeSSA, MFA, Options, Servers) ->
    ?option_time(hipe_icode_type:cfg(IcodeSSA, MFA, Options, Servers),
		 io_lib:format("Icode SSA type info for ~p", [MFA]), Options).

icode_range_analysis(IcodeSSA, MFA, Options, Servers) ->
  case proplists:get_bool(icode_range, Options) of
    true ->
      ?option_time(hipe_icode_range:cfg(IcodeSSA, MFA, Options, Servers), 
		   "Icode SSA integer range analysis", Options);
    false ->
     IcodeSSA
  end.

icode_eliminate_safe_calls(IcodeSSA, Options) ->
  case proplists:get_bool(icode_call_elim, Options) of
    true ->
      ?option_time(hipe_icode_call_elim:cfg(IcodeSSA),
		   "Icode SSA safe call elimination", Options);
    false ->
     IcodeSSA
  end.

icode_ssa_dead_code_elimination(IcodeSSA, Options) ->
  IcodeSSA1 = ?option_time(hipe_icode_ssa:remove_dead_code(IcodeSSA),
			   "Icode SSA dead code elimination pass 2", 
			   Options),
  hipe_icode_cfg:remove_unreachable_code(IcodeSSA1).

icode_ssa_check(IcodeSSA, Options) ->
  ?when_option(icode_ssa_check, Options,
	       ?option_time(hipe_icode_ssa:check(IcodeSSA),
			    "Icode check for SSA-ness", Options)).

icode_ssa_unconvert(IcodeSSA, Options) ->
  ?option_time(hipe_icode_ssa:unconvert(IcodeSSA),
	       "Icode SSA unconversion", Options).


%%=====================================================================
%%
%% @spec icode_to_rtl(MFA::mfa(), Icode, options()) -> Linear_RTL_code
%% @end
%%=====================================================================

%%---------------------------------------------------------------------
%%
%% The passes on RTL are as follows:
%%
%% 1. The translation to RTL, in particular the way exceptions are
%%    currently handled in RTL, introduces some unreachable code.
%%    Therefore, unreachable code is removed early on followed by a
%%    pass that removes trivial basic blocks so as to have smaller
%%    code to play with.
%%
%% 2. Code is then converted to SSA so as to perform as many
%%    optimizations as possible in this pass.
%%    Currently, the following optimizations are performed on SSA:
%%      - sparse conditional constant propagation (controlled by an option)
%%	- dead code elimination
%%	- detection of available exceptions
%%	- partial redundancy elimination (controlled by an option)
%%    Finally, code is converted back to non-SSA form.
%%
%% 3. rtl_symbolic expands some symbolic instructions.
%%
%% 4. rtl_lcm performs a lazy code motion on RTL.
%%
%%----------------------------------------------------------------------
 
icode_to_rtl(MFA, Icode, Options, Servers) ->
  debug("ICODE -> RTL: ~w, ~w~n", [MFA, hash(Icode)], Options),
  LinearRTL = translate_to_rtl(Icode, Options),
  pp(LinearRTL, MFA, rtl_linear, pp_rtl_linear, Options, Servers),
  RtlCfg  = initialize_rtl_cfg(LinearRTL, Options),
  %% hipe_rtl_cfg:pp(RtlCfg),
  RtlCfg0 = hipe_rtl_cfg:remove_unreachable_code(RtlCfg),
  RtlCfg1 = hipe_rtl_cfg:remove_trivial_bbs(RtlCfg0),
  %% hipe_rtl_cfg:pp(RtlCfg1),
  RtlCfg2 = rtl_ssa(RtlCfg1, Options),
  RtlCfg3 = rtl_symbolic(RtlCfg2, Options),
  %% hipe_rtl_cfg:pp(RtlCfg3),
  pp(RtlCfg3, MFA, rtl_liveness, pp_rtl_liveness, Options, Servers),
  RtlCfg4 = rtl_lcm(RtlCfg3, Options),
  %% LLVM: A liveness analysis on RTL must be performed in order to find the GC
  %% roots and explicitly mark them (in RTL) when they go out of scope (only
  %% when the LLVM backend is used).
  {RtlCfg5, Roots} =
    case proplists:get_bool(to_llvm, Options) of
      false ->
        {RtlCfg4, []};
      true ->
        hipe_llvm_liveness:analyze(RtlCfg4)
    end,
  pp(RtlCfg5, MFA, rtl, pp_rtl, Options, Servers),
  LinearRTL1 = hipe_rtl_cfg:linearize(RtlCfg5),
  LinearRTL2 = hipe_rtl_cleanup_const:cleanup(LinearRTL1),
  %% hipe_rtl:pp(standard_io, LinearRTL2),
  {LinearRTL2, Roots}.

translate_to_rtl(Icode, Options) ->
  %% GC tests should have been added in the conversion to Icode.
  ?option_time(hipe_icode2rtl:translate(Icode, Options),
	       "translate", Options).

initialize_rtl_cfg(LinearRTL, Options) ->
  ?option_time(hipe_rtl_cfg:init(LinearRTL), "to cfg", Options).

rtl_symbolic(RtlCfg, Options) ->
  ?option_time(hipe_rtl_symbolic:expand(RtlCfg),
	       "Expansion of symbolic instructions", Options).

%%----------------------------------------------------------------------
%%
%% RTL passes on SSA form. The following constraints are applicable:
%% 
%% 1. ssa_convert must be first and ssa_unconvert last.
%%
%% 2. dead_code_elimination should be performed after conditional
%%    constant propagation in order to cleanup dead code that might
%%    be created by that pass.
%%
%% 3. avail_expr ... (PER ADD THIS)
%%
%% 4. rtl_ssapre performs A-SSAPRE and has to be done after all other
%%    optimizations.
%%
%% 5. ssa_check could be put in between all passes to make sure that
%%    they preserve SSA-ness.
%%
%%----------------------------------------------------------------------

rtl_ssa(RtlCfg0, Options) ->
  case proplists:get_bool(rtl_ssa, Options) of
    true ->
      ?opt_start_timer("RTL SSA passes"),
      RtlSSA0 = rtl_ssa_convert(RtlCfg0, Options),
      RtlSSA1 = rtl_ssa_const_prop(RtlSSA0, Options),
      %% RtlSSA1a = rtl_ssa_copy_prop(RtlSSA1, Options),
      RtlSSA2 = rtl_ssa_dead_code_elimination(RtlSSA1, Options),
      RtlSSA3 = rtl_ssa_avail_expr(RtlSSA2, Options),
      RtlSSA4 = rtl_ssapre(RtlSSA3, Options),
      %% rtl_ssa_check(RtlSSA4, Options), %% just for sanity
      RtlCfg = rtl_ssa_unconvert(RtlSSA4, Options),
      case proplists:get_bool(pp_rtl_ssa, Options) of
	true ->
	  io:format("%%------------- After  SSA un-conversion -----------\n"),
	  hipe_rtl_cfg:pp(RtlCfg);
	false ->
	  ok
      end,
      ?opt_stop_timer("RTL SSA passes"),
      RtlCfg;
    false ->
      RtlCfg0
  end.

rtl_ssa_convert(RtlCfg, Options) ->
  case proplists:get_bool(pp_rtl_ssa, Options) of
    true ->
      io:format("%%------------- Before SSA conversion --------------\n"),
      hipe_rtl_cfg:pp(RtlCfg),
      io:format("%%------------- After  SSA conversion --------------\n"),
      RtlCfgSSA = hipe_rtl_ssa:convert(RtlCfg),
      hipe_rtl_cfg:pp(RtlCfgSSA),
      io:format("%%------------- SSA check warnings below -----------\n"),
      hipe_rtl_ssa:check(RtlCfgSSA),
      RtlCfgSSA;
    false ->
      ?option_time(hipe_rtl_ssa:convert(RtlCfg),
		   "RTL SSA conversion", Options)
  end.

rtl_ssa_const_prop(RtlCfgSSA, Options) ->
  case proplists:get_bool(rtl_ssa_const_prop, Options) of
    true ->
      ?option_time(hipe_rtl_ssa_const_prop:propagate(RtlCfgSSA),
		   "RTL SSA sparse conditional constant propagation", Options);
    false ->
      RtlCfgSSA
  end.

rtl_ssa_dead_code_elimination(RtlCfgSSA, Options) ->
  ?option_time(hipe_rtl_ssa:remove_dead_code(RtlCfgSSA),
	       "RTL SSA dead code elimination", Options).

rtl_ssa_avail_expr(RtlCfgSSA, Options) ->
  ?option_time(hipe_rtl_ssa_avail_expr:cfg(RtlCfgSSA),
	       "RTL SSA heap optimizations", Options).

%%---------------------------------------------------------------------

rtl_ssapre(RtlCfg, Options) ->
  case proplists:get_bool(rtl_ssapre, Options) of
    true ->
      ?opt_start_timer("Partial Redundancy Elimination (A-SSAPRE)"),
      NewRtlCfg = hipe_rtl_ssapre:rtl_ssapre(RtlCfg, Options),
      ?opt_stop_timer("Partial Redundancy Elimination (A-SSAPRE)"),
      NewRtlCfg;
    false ->
      RtlCfg
  end.

%%---------------------------------------------------------------------

rtl_ssa_unconvert(RtlCfgSSA, Options) ->
  ?option_time(hipe_rtl_ssa:unconvert(RtlCfgSSA),
	       "RTL SSA un-convert", Options).

%%---------------------------------------------------------------------

rtl_lcm(RtlCfg, Options) ->
  case proplists:get_bool(rtl_lcm, Options) of
    true ->
      ?opt_start_timer("RTL lazy code motion"),
      %% ?option_time(hipe_rtl_lcm:rtl_lcm(RtlCfg, Options),
      %%	      "RTL lazy code motion", Options);
      RtlCfg1 = hipe_rtl_lcm:rtl_lcm(RtlCfg, Options),
      ?opt_stop_timer("RTL lazy code motion"),
      RtlCfg1;
    false ->
      RtlCfg
  end.

%%=====================================================================
%% Translation to native code takes place in the corresponding back-end
%%=====================================================================

rtl_to_native(MFA, LinearRTL, Options, DebugState) ->
  ?opt_start_timer("Native code"),
  LinearNativeCode =
    case get(hipe_target_arch) of
      ultrasparc ->
	hipe_sparc_main:rtl_to_sparc(MFA, LinearRTL, Options);
      powerpc ->
	hipe_ppc_main:rtl_to_ppc(MFA, LinearRTL, Options);
      ppc64 ->
	hipe_ppc_main:rtl_to_ppc(MFA, LinearRTL, Options);
      arm ->
	hipe_arm_main:rtl_to_arm(MFA, LinearRTL, Options);
      x86 ->
	hipe_x86_main:rtl_to_x86(MFA, LinearRTL, Options);
      amd64 ->
	hipe_amd64_main:rtl_to_amd64(MFA, LinearRTL, Options)
    end,
  ?opt_stop_timer("Native code"),
  put(hipe_debug, DebugState),
  LinearNativeCode.

%% Translate Linear RTL to binary code using LLVM.
rtl_to_llvm_to_binary(MFA, LinearRTL, Roots, Options, DebugState) ->
  ?opt_start_timer("LLVM native code"),
  %% BinaryCode is a tuple, as defined in llvm/hipe_llvm_main module, which
  %% contains the binary code together with info needed by the loader, e.g.
  %% ConstTab, Refs, LabelMap, etc.
  BinaryCode = hipe_llvm_main:rtl_to_native(MFA, LinearRTL, Roots, Options),
  ?opt_stop_timer("LLVM native code"),
  put(hipe_debug, DebugState),
  {llvm_binary, BinaryCode}.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Debugging stuff ...
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

debug(Text, Args, Options) ->
  ?when_option(debug, Options, ?msg(Text,Args)).

hash(X) ->
  erlang:phash(X, 16#7f3f5f1).