components/web/firefox/patches/firefox-92-memory-tracker.patch

   1 Solaris x86_64 allocates some user space memory in the canonical
   2 'higher half' of the address space.  Consequently, on Solaris x86_64,
   3 a pointer may reference either the lower half or higher half.
   4
   5 As the MemoryTracker persists only the low order 56 bits, we must
   6 reconstitute the high order bits in this case, as they may well not
   7 be zero.
   8
   9 We can recover the bits easily, though, as the x86_64 specification
  10 requires the most significant 16 bits of any virtual address, bits 48
  11 through 63, be copies of bit 47, in a manner akin to sign extension.
  12
  13 Suitable for upstream, though not a likely candidate, as Solaris seems
  14 to be the only operating system that allocates user space memory in
  15 the higher half.
  16
  17
  18 --- a/js/src/gc/Scheduling.cpp  2021-08-16 19:14:35.000000000 +0000
  19 +++ b/js/src/gc/Scheduling.cpp  2021-09-06 17:12:00.451552042 +0000
  20 @@ -809,7 +809,11 @@
  21
  22  template <typename Ptr>
  23  inline Ptr* MemoryTracker::Key<Ptr>::ptr() const {
  24 +#  ifdef __x86_64__
  25 +  return reinterpret_cast<Ptr*>((static_cast<intptr_t>(ptr_) << 16) >> 16);
  26 +#  else
  27    return reinterpret_cast<Ptr*>(ptr_);
  28 +#  endif
  29  }
  30  template <typename Ptr>
  31  inline MemoryUse MemoryTracker::Key<Ptr>::use() const {