git.libre-soc.org Git - buildroot.git/blob

   1 From 903a79a1efff18fc7cc50db09a3fe5d768adc9a8 Mon 19 Mar 2018 09:58:06 +0100
   2 From: Lars T Hansen <lhansen@mozilla.com>
   3 Date: Fri, 23 Mar 2018 22:01:33 +0000
   4 Subject: [PATCH] save and restore non-volatile x28 on ARM64 for generated unboxed object constructor
   5
   6 Fixes: https://bugzilla.mozilla.org/show_bug.cgi?id=1375074
   7
   8 Upsream-status: Applied
   9 See: https://hg.mozilla.org/mozilla-central/rev/800abe66894d
  10
  11 Signed-off-by: Lars T Hansen <lhansen@mozilla.com>
  12 Signed-off-by: Adam Duskett <aduskett@gmail.com>
  13 ---
  14  js/src/vm/UnboxedObject.cpp | 30 ++++++++++++++++++++++++++----
  15  1 file changed, 26 insertions(+), 4 deletions(-)
  16
  17 diff --git a/js/src/vm/UnboxedObject.cpp b/js/src/vm/UnboxedObject.cpp
  18 index 35ca20d7405f..1c20a1093d13 100644
  19 --- a/js/src/vm/UnboxedObject.cpp
  20 +++ b/js/src/vm/UnboxedObject.cpp
  21 @@ -86,9 +86,16 @@ static const uintptr_t CLEAR_CONSTRUCTOR_CODE_TOKEN = 0x1;
  22  #endif
  23
  24  #ifdef JS_CODEGEN_ARM64
  25 -  // ARM64 communicates stack address via sp, but uses a pseudo-sp for
  26 -  // addressing.
  27 -  masm.initStackPtr();
  28 +    // ARM64 communicates stack address via sp, but uses a pseudo-sp (PSP) for
  29 +    // addressing.  The register we use for PSP may however also be used by
  30 +    // calling code, and it is nonvolatile, so save it.  Do this as a special
  31 +    // case first because the generic save/restore code needs the PSP to be
  32 +    // initialized already.
  33 +    MOZ_ASSERT(PseudoStackPointer64.Is(masm.GetStackPointer64()));
  34 +    masm.Str(PseudoStackPointer64, vixl::MemOperand(sp, -16, vixl::PreIndex));
  35 +
  36 +    // Initialize the PSP from the SP.
  37 +    masm.initStackPtr();
  38  #endif
  39
  40    MOZ_ASSERT(propertiesReg.volatile_());
  41 @@ -239,7 +246,22 @@ static const uintptr_t CLEAR_CONSTRUCTOR_CODE_TOKEN = 0x1;
  42    if (ScratchDoubleReg.volatile_()) masm.pop(ScratchDoubleReg);
  43    masm.PopRegsInMask(savedNonVolatileRegisters);
  44
  45 -  masm.abiret();
  46 +#ifdef JS_CODEGEN_ARM64
  47 +    // Now restore the value that was in the PSP register on entry, and return.
  48 +
  49 +    // Obtain the correct SP from the PSP.
  50 +    masm.Mov(sp, PseudoStackPointer64);
  51 +
  52 +    // Restore the saved value of the PSP register, this value is whatever the
  53 +    // caller had saved in it, not any actual SP value, and it must not be
  54 +    // overwritten subsequently.
  55 +    masm.Ldr(PseudoStackPointer64, vixl::MemOperand(sp, 16, vixl::PostIndex));
  56 +
  57 +    // Perform a plain Ret(), as abiret() will move SP <- PSP and that is wrong.
  58 +    masm.Ret(vixl::lr);
  59 +#else
  60 +    masm.abiret();
  61 +#endif
  62
  63    masm.bind(&failureStoreOther);
  64
  65 --
  66 2.23.0