js/src/jit/AliasAnalysis.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef jit_AliasAnalysis_h
   8 #define jit_AliasAnalysis_h
   9
  10 #include "jit/MIR.h"
  11 #include "jit/MIRGraph.h"
  12
  13 namespace js {
  14 namespace jit {
  15
  16 class LoopAliasInfo;
  17
  18 class AliasAnalysis {
  19   MIRGenerator* mir;
  20   MIRGraph& graph_;
  21   LoopAliasInfo* loop_;
  22
  23   void spewDependencyList();
  24
  25   TempAllocator& alloc() const { return graph_.alloc(); }
  26
  27  public:
  28   AliasAnalysis(MIRGenerator* mir, MIRGraph& graph)
  29       : mir(mir), graph_(graph), loop_(nullptr) {}
  30
  31   [[nodiscard]] bool analyze();
  32 };
  33
  34 // Iterates over the flags in an AliasSet.
  35 class AliasSetIterator {
  36  private:
  37   uint32_t flags;
  38   unsigned pos;
  39
  40  public:
  41   explicit AliasSetIterator(AliasSet set) : flags(set.flags()), pos(0) {
  42     while (flags && (flags & 1) == 0) {
  43       flags >>= 1;
  44       pos++;
  45     }
  46   }
  47   AliasSetIterator& operator++(int) {
  48     do {
  49       flags >>= 1;
  50       pos++;
  51     } while (flags && (flags & 1) == 0);
  52     return *this;
  53   }
  54   explicit operator bool() const { return !!flags; }
  55   unsigned operator*() const {
  56     MOZ_ASSERT(pos < AliasSet::NumCategories);
  57     return pos;
  58   }
  59 };
  60
  61 }  // namespace jit
  62 }  // namespace js
  63
  64 #endif /* jit_AliasAnalysis_h */