mozilla-bmo1375074.patch
changeset 1055 526f445635f3
parent 1054 fbfe323c62cd
child 1056 90e1f32cf034
--- a/mozilla-bmo1375074.patch	Fri Jun 08 22:31:03 2018 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,95 +0,0 @@
-
-# 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
-
-diff --git a/js/src/jit-test/tests/bug1375074.js b/js/src/jit-test/tests/bug1375074.js
-new file mode 100644
---- /dev/null
-+++ b/js/src/jit-test/tests/bug1375074.js
-@@ -0,0 +1,18 @@
-+// This forces the VM to start creating unboxed objects and thus stresses a
-+// particular path into generated code for a specialized unboxed object
-+// constructor.
-+
-+var K = 2000;			// 2000 should be plenty
-+var s = "[";
-+var i;
-+for ( i=0; i < K-1; i++ )
-+    s = s + `{"i":${i}},`;
-+s += `{"i":${i}}]`;
-+var v = JSON.parse(s);
-+
-+assertEq(v.length == K, true);
-+
-+for ( i=0; i < K; i++) {
-+    assertEq(v[i] instanceof Object, true);
-+    assertEq(v[i].i, i);
-+}
-diff --git a/js/src/vm/UnboxedObject.cpp b/js/src/vm/UnboxedObject.cpp
---- a/js/src/vm/UnboxedObject.cpp
-+++ b/js/src/vm/UnboxedObject.cpp
-@@ -90,17 +90,25 @@ UnboxedLayout::makeConstructorCode(JSCon
-     masm.loadPtr(Address(masm.getStackPointer(), sizeof(void*)), propertiesReg);
-     masm.loadPtr(Address(masm.getStackPointer(), 2 * sizeof(void*)), newKindReg);
- #else
-     propertiesReg = IntArgReg0;
-     newKindReg = IntArgReg1;
- #endif
- 
- #ifdef JS_CODEGEN_ARM64
--    // ARM64 communicates stack address via sp, but uses a pseudo-sp for addressing.
-+    // 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_());
-     MOZ_ASSERT(newKindReg.volatile_());
- 
-     AllocatableGeneralRegisterSet regs(GeneralRegisterSet::All());
-     regs.take(propertiesReg);
-@@ -228,17 +236,32 @@ UnboxedLayout::makeConstructorCode(JSCon
-     if (object != ReturnReg)
-         masm.movePtr(object, ReturnReg);
- 
-     // Restore non-volatile registers which were saved on entry.
-     if (ScratchDoubleReg.volatile_())
-         masm.pop(ScratchDoubleReg);
-     masm.PopRegsInMask(savedNonVolatileRegisters);
- 
-+#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);
- 
-     // There was a failure while storing a value which cannot be stored at all
-     // in the unboxed object. Initialize the object so it is safe for GC and
-     // return null.
-     masm.initUnboxedObjectContents(object, templateObject);
- 
-