Revert "ARM64: use jssp for stack slots"

src/arm64/lithium-codegen-arm64.h

Index: src/arm64/lithium-codegen-arm64.h
diff --git a/src/arm64/lithium-codegen-arm64.h b/src/arm64/lithium-codegen-arm64.h
index fe16a4e59ccdb1154c95dbe5c7ca02caf994229a..d94262e74dd9ec24a9882e45976fece32fd29a90 100644
--- a/src/arm64/lithium-codegen-arm64.h
+++ b/src/arm64/lithium-codegen-arm64.h
@@ -37,16 +37,10 @@ class LCodeGen: public LCodeGenBase {
         frame_is_built_(false),
         safepoints_(info->zone()),
         resolver_(this),
-        expected_safepoint_kind_(Safepoint::kSimple),
-        after_push_argument_(false),
-        inlined_arguments_(false) {
+        expected_safepoint_kind_(Safepoint::kSimple) {
     PopulateDeoptimizationLiteralsWithInlinedFunctions();
   }
 
-  ~LCodeGen() {
-    DCHECK(!after_push_argument_ || inlined_arguments_);
-  }
-
   // Simple accessors.
   Scope* scope() const { return scope_; }
 
@@ -87,9 +81,7 @@ class LCodeGen: public LCodeGenBase {
   Register ToRegister32(LOperand* op) const;
   Operand ToOperand(LOperand* op);
   Operand ToOperand32(LOperand* op);
-  enum StackMode { kMustUseFramePointer, kCanUseStackPointer };
-  MemOperand ToMemOperand(LOperand* op,
-                          StackMode stack_mode = kCanUseStackPointer) const;
+  MemOperand ToMemOperand(LOperand* op) const;
   Handle<Object> ToHandle(LConstantOperand* op) const;
 
   template <class LI>
@@ -366,15 +358,6 @@ class LCodeGen: public LCodeGenBase {
 
   Safepoint::Kind expected_safepoint_kind_;
 
-  // This flag is true when we are after a push (but before a call).
-  // In this situation, jssp no longer references the end of the stack slots so,
-  // we can only reference a stack slot via fp.
-  bool after_push_argument_;
-  // If we have inlined arguments, we are no longer able to use jssp because
-  // jssp is modified and we never know if we are in a block after or before
-  // the pop of the arguments (which restores jssp).
-  bool inlined_arguments_;
-
   int old_position_;
 
   class PushSafepointRegistersScope BASE_EMBEDDED {