hphp/runtime/vm/jit/guard-relaxation.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-2014 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
  17 #ifndef incl_HPHP_RUNTIME_VM_JIT_GUARD_RELAXATION_H_
  18 #define incl_HPHP_RUNTIME_VM_JIT_GUARD_RELAXATION_H_
  19
  20 #include "hphp/runtime/base/datatype.h"
  21 #include "hphp/runtime/vm/jit/region-selection.h"
  22 #include "hphp/runtime/vm/jit/type-constraint.h"
  23 #include "hphp/runtime/vm/jit/type.h"
  24
  25 #include "hphp/runtime/vm/jit/block.h"
  26
  27 namespace HPHP { namespace jit {
  28
  29 struct GuardConstraints;
  30 struct IRUnit;
  31 struct SSATmp;
  32
  33 enum RelaxGuardsFlags {
  34   RelaxNormal =      0,
  35   RelaxSimple = 1 << 0,
  36   RelaxReflow = 1 << 1,
  37 };
  38
  39 bool shouldHHIRRelaxGuards();
  40
  41 /*
  42  * Given a possibly null SSATmp*, determine if the type of that tmp may be
  43  * loosened by guard relaxation.
  44  */
  45 bool typeMightRelax(const SSATmp* tmp);
  46
  47 bool relaxGuards(IRUnit&, const GuardConstraints& guards,
  48                  RelaxGuardsFlags flags);
  49
  50 /*
  51  * Returns true iff `t' is specific enough to fit `cat', meaning a consumer
  52  * constraining a value with `cat' would be satisfied with `t' as the value's
  53  * type after relaxation.
  54  */
  55 bool typeFitsConstraint(Type t, TypeConstraint cat);
  56
  57 Type relaxType(Type t, TypeConstraint cat);
  58 TypeConstraint relaxConstraint(const TypeConstraint origTc,
  59                                const Type knownType, const Type toRelax);
  60 TypeConstraint applyConstraint(TypeConstraint origTc, TypeConstraint newTc);
  61
  62 } }
  63
  64 #endif