hphp/hhbbc/dce.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16 #pragma once
  17
  18 #include <vector>
  19
  20 #include "hphp/runtime/base/type-string.h"
  21
  22 #include "hphp/hhbbc/misc.h"
  23
  24 namespace HPHP::HHBBC {
  25
  26 //////////////////////////////////////////////////////////////////////
  27
  28 namespace php { struct WideFunc; }
  29
  30 struct FuncAnalysis;
  31 struct Index;
  32 struct State;
  33 struct VisitContext;
  34
  35 //////////////////////////////////////////////////////////////////////
  36
  37 /*
  38  * Perform DCE on a single basic block.
  39  */
  40 void local_dce(VisitContext& visit, BlockId bid, const State&);
  41
  42 /*
  43  * Eliminate dead code in a function, across basic blocks, based on
  44  * results from a previous analyze_func call.
  45  *
  46  * Returns true if we should re-run the optimizer.
  47  */
  48 bool global_dce(const Index&, const FuncAnalysis&, php::WideFunc&);
  49
  50 //////////////////////////////////////////////////////////////////////
  51
  52 const StaticString s_unreachable("static analysis error: supposedly "
  53                                  "unreachable code was reached");
  54
  55 //////////////////////////////////////////////////////////////////////
  56
  57 }
  58