1 files changed, 25 insertions, 16 deletions

diff --git a/deps/v8/src/compiler/linkage.cc b/deps/v8/src/compiler/linkage.cc
index 03b8074f0f..5df50e64f5 100644
--- a/deps/v8/src/compiler/linkage.cc
+++ b/deps/v8/src/compiler/linkage.cc
@@ -75,33 +75,42 @@ bool CallDescriptor::HasSameReturnLocationsAs(
   return true;
 }
 
-int CallDescriptor::GetStackParameterDelta(
-    CallDescriptor const* tail_caller) const {
-  int callee_slots_above_sp = 0;
+int CallDescriptor::GetFirstUnusedStackSlot() const {
+  int slots_above_sp = 0;
   for (size_t i = 0; i < InputCount(); ++i) {
     LinkageLocation operand = GetInputLocation(i);
     if (!operand.IsRegister()) {
       int new_candidate =
           -operand.GetLocation() + operand.GetSizeInPointers() - 1;
-      if (new_candidate > callee_slots_above_sp) {
-        callee_slots_above_sp = new_candidate;
+      if (new_candidate > slots_above_sp) {
+        slots_above_sp = new_candidate;
       }
     }
   }
-  int tail_caller_slots_above_sp = 0;
-  if (tail_caller != nullptr) {
-    for (size_t i = 0; i < tail_caller->InputCount(); ++i) {
-      LinkageLocation operand = tail_caller->GetInputLocation(i);
-      if (!operand.IsRegister()) {
-        int new_candidate =
-            -operand.GetLocation() + operand.GetSizeInPointers() - 1;
-        if (new_candidate > tail_caller_slots_above_sp) {
-          tail_caller_slots_above_sp = new_candidate;
-        }
+  return slots_above_sp;
+}
+
+int CallDescriptor::GetStackParameterDelta(
+    CallDescriptor const* tail_caller) const {
+  int callee_slots_above_sp = GetFirstUnusedStackSlot();
+  int tail_caller_slots_above_sp = tail_caller->GetFirstUnusedStackSlot();
+  int stack_param_delta = callee_slots_above_sp - tail_caller_slots_above_sp;
+  if (kPadArguments) {
+    // Adjust stack delta when it is odd.
+    if (stack_param_delta % 2 != 0) {
+      if (callee_slots_above_sp % 2 != 0) {
+        // The delta is odd due to the callee - we will need to add one slot
+        // of padding.
+        ++stack_param_delta;
+      } else {
+        // The delta is odd because of the caller. We already have one slot of
+        // padding that we can reuse for arguments, so we will need one fewer
+        // slot.
+        --stack_param_delta;
       }
     }
   }
-  return callee_slots_above_sp - tail_caller_slots_above_sp;
+  return stack_param_delta;
 }
 
 bool CallDescriptor::CanTailCall(const Node* node) const {