1 files changed, 64 insertions, 0 deletions
diff --git a/source/l/mozjs60/patches/Save-and-restore-non-volatile-x28-on-ARM64-for-generated-unboxed-object-constructor.patch b/source/l/mozjs60/patches/Save-and-restore-non-volatile-x28-on-ARM64-for-generated-unboxed-object-constructor.patch
new file mode 100644
index 000000000..46d280d06
--- /dev/null
+++ b/source/l/mozjs60/patches/Save-and-restore-non-volatile-x28-on-ARM64-for-generated-unboxed-object-constructor.patch
@@ -0,0 +1,64 @@
+# HG changeset patch
+# User Lars T Hansen <lhansen@mozilla.com>
+# Date 1519822672 -3600
+# Node ID 800abe66894d6b07b24bccecbf6a65e2261076f6
+# Parent  223c97459e96183eb616aed39147207bdb953ba8
+Bug 1375074 - Save and restore non-volatile x28 on ARM64 for generated unboxed object constructor.  r=sstangl
+
+Origin: upstream
+Applied-upstream: 61, commit: https://hg.mozilla.org/mozilla-central/rev/800abe66894d
+---
+ js/src/vm/UnboxedObject.cpp | 30 ++++++++++++++++++++++++++----
+ 1 file changed, 26 insertions(+), 4 deletions(-)
+
+diff --git a/js/src/vm/UnboxedObject.cpp b/js/src/vm/UnboxedObject.cpp
+index 35ca20d7405f..1c20a1093d13 100644
+--- a/js/src/vm/UnboxedObject.cpp
++++ b/js/src/vm/UnboxedObject.cpp
+@@ -86,9 +86,16 @@ static const uintptr_t CLEAR_CONSTRUCTOR_CODE_TOKEN = 0x1;
+ #endif
+
+ #ifdef JS_CODEGEN_ARM64
+-  // ARM64 communicates stack address via sp, but uses a pseudo-sp for
+-  // addressing.
+-  masm.initStackPtr();
++    // ARM64 communicates stack address via sp, but uses a pseudo-sp (PSP) for
++    // addressing.  The register we use for PSP may however also be used by
++    // calling code, and it is nonvolatile, so save it.  Do this as a special
++    // case first because the generic save/restore code needs the PSP to be
++    // initialized already.
++    MOZ_ASSERT(PseudoStackPointer64.Is(masm.GetStackPointer64()));
++    masm.Str(PseudoStackPointer64, vixl::MemOperand(sp, -16, vixl::PreIndex));
++
++    // Initialize the PSP from the SP.
++    masm.initStackPtr();
+ #endif
+
+   MOZ_ASSERT(propertiesReg.volatile_());
+@@ -239,7 +246,22 @@ static const uintptr_t CLEAR_CONSTRUCTOR_CODE_TOKEN = 0x1;
+   if (ScratchDoubleReg.volatile_()) masm.pop(ScratchDoubleReg);
+   masm.PopRegsInMask(savedNonVolatileRegisters);
+
+-  masm.abiret();
++#ifdef JS_CODEGEN_ARM64
++    // Now restore the value that was in the PSP register on entry, and return.
++
++    // Obtain the correct SP from the PSP.
++    masm.Mov(sp, PseudoStackPointer64);
++
++    // Restore the saved value of the PSP register, this value is whatever the
++    // caller had saved in it, not any actual SP value, and it must not be
++    // overwritten subsequently.
++    masm.Ldr(PseudoStackPointer64, vixl::MemOperand(sp, 16, vixl::PostIndex));
++
++    // Perform a plain Ret(), as abiret() will move SP <- PSP and that is wrong.
++    masm.Ret(vixl::lr);
++#else
++    masm.abiret();
++#endif
+
+   masm.bind(&failureStoreOther);
+
+--
+2.21.0
+