ppc: implement reverse js arg

Change-Id: Ica6b886ca0b16ab6eb86f3a90c598a0801230648
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2385918Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69640}

src/codegen/ppc/macro-assembler-ppc.cc

@@ -320,6 +320,38 @@ void TurboAssembler::Push(Smi smi) {
   push(r0);
 }
 
+void TurboAssembler::PushArray(Register array, Register size, Register scratch,
+                               Register scratch2, PushArrayOrder order) {
+  Label loop, done;
+
+  if (order == kNormal) {
+    cmpi(size, Operand::Zero());
+    beq(&done);
+    ShiftLeftImm(scratch, size, Operand(kSystemPointerSizeLog2));
+    add(scratch, array, scratch);
+    mtctr(size);
+
+    bind(&loop);
+    LoadPU(scratch2, MemOperand(scratch, -kSystemPointerSize));
+    StorePU(scratch2, MemOperand(sp, -kSystemPointerSize));
+    bdnz(&loop);
+
+    bind(&done);
+  } else {
+    cmpi(size, Operand::Zero());
+    beq(&done);
+
+    mtctr(size);
+    subi(scratch, array, Operand(kSystemPointerSize));
+
+    bind(&loop);
+    LoadPU(scratch2, MemOperand(scratch, kSystemPointerSize));
+    StorePU(scratch2, MemOperand(sp, -kSystemPointerSize));
+    bdnz(&loop);
+    bind(&done);
+  }
+}
+
 void TurboAssembler::Move(Register dst, Handle<HeapObject> value,
                           RelocInfo::Mode rmode) {
   // TODO(jgruber,v8:8887): Also consider a root-relative load when generating
@@ -1350,8 +1382,7 @@ void MacroAssembler::CheckDebugHook(Register fun, Register new_target,
 
   {
     // Load receiver to pass it later to DebugOnFunctionCall hook.
-    ShiftLeftImm(r7, actual_parameter_count, Operand(kSystemPointerSizeLog2));
-    LoadPX(r7, MemOperand(sp, r7));
+    LoadReceiver(r7, actual_parameter_count);
     FrameScope frame(this,
                      has_frame() ? StackFrame::NONE : StackFrame::INTERNAL);
 

src/codegen/ppc/macro-assembler-ppc.h

@@ -237,6 +237,10 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
     StoreP(src1, MemOperand(sp, 4 * kSystemPointerSize));
   }
 
+  enum PushArrayOrder { kNormal, kReverse };
+  void PushArray(Register array, Register size, Register scratch,
+                 Register scratch2, PushArrayOrder order = kNormal);
+
   void Pop(Register dst) { pop(dst); }
 
   // Pop two registers. Pops rightmost register first (from lower address).
@@ -719,6 +723,28 @@ class V8_EXPORT_PRIVATE MacroAssembler : public TurboAssembler {
  public:
   using TurboAssembler::TurboAssembler;
 
+  // It assumes that the arguments are located below the stack pointer.
+  // argc is the number of arguments not including the receiver.
+  // TODO(victorgomes): Remove this function once we stick with the reversed
+  // arguments order.
+  void LoadReceiver(Register dest, Register argc) {
+#ifdef V8_REVERSE_JSARGS
+    LoadP(dest, MemOperand(sp, 0));
+#else
+    ShiftLeftImm(dest, argc, Operand(kSystemPointerSizeLog2));
+    LoadPX(dest, MemOperand(sp, dest));
+#endif
+  }
+
+  void StoreReceiver(Register rec, Register argc, Register scratch) {
+#ifdef V8_REVERSE_JSARGS
+    StoreP(rec, MemOperand(sp, 0));
+#else
+    ShiftLeftImm(scratch, argc, Operand(kSystemPointerSizeLog2));
+    StorePX(rec, MemOperand(sp, scratch));
+#endif
+  }
+
   // ---------------------------------------------------------------------------
   // GC Support