8387637: Dead code for upwards interpreter stacks

Reviewed-by: coleenp, dholmes, shade

src/hotspot/cpu/aarch64/frame_aarch64.hpp

@@ -186,8 +186,6 @@
   // deoptimization support
   void interpreter_frame_set_last_sp(intptr_t* sp);
 
-  static jint interpreter_frame_expression_stack_direction() { return -1; }
-
   // returns the sending frame, without applying any barriers
   inline frame sender_raw(RegisterMap* map) const;
 

src/hotspot/cpu/arm/frame_arm.hpp

@@ -122,6 +122,4 @@
   // helper to update a map with callee-saved FP
   static void update_map_with_saved_link(RegisterMap* map, intptr_t** link_addr);
 
-  static jint interpreter_frame_expression_stack_direction() { return -1; }
-
 #endif // CPU_ARM_FRAME_ARM_HPP

src/hotspot/cpu/ppc/frame_ppc.hpp

@@ -407,8 +407,6 @@
     align_wiggle                           =  1
   };
 
-  static jint interpreter_frame_expression_stack_direction() { return -1; }
-
   // returns the sending frame, without applying any barriers
   inline frame sender_raw(RegisterMap* map) const;
 

src/hotspot/cpu/riscv/frame_riscv.hpp

@@ -218,8 +218,6 @@
   // deoptimization support
   void interpreter_frame_set_last_sp(intptr_t* last_sp);
 
-  static jint interpreter_frame_expression_stack_direction() { return -1; }
-
   // returns the sending frame, without applying any barriers
   inline frame sender_raw(RegisterMap* map) const;
 

src/hotspot/cpu/s390/frame_s390.hpp

@@ -572,8 +572,6 @@
     align_wiggle             =  0
   };
 
-  static jint interpreter_frame_expression_stack_direction() { return -1; }
-
   // returns the sending frame, without applying any barriers
   inline frame sender_raw(RegisterMap* map) const;
 

src/hotspot/cpu/x86/frame_x86.hpp

@@ -170,8 +170,6 @@
   // deoptimization support
   void interpreter_frame_set_last_sp(intptr_t* sp);
 
-  static jint interpreter_frame_expression_stack_direction() { return -1; }
-
   // returns the sending frame, without applying any barriers
   inline frame sender_raw(RegisterMap* map) const;
 

src/hotspot/cpu/zero/frame_zero.hpp

@@ -82,8 +82,6 @@
                            char*         buf,
                            int           buflen) const;
 
-  static jint interpreter_frame_expression_stack_direction() { return -1; }
-
   inline address* sender_pc_addr() const;
 
   template <typename RegisterMapT>

src/hotspot/share/interpreter/abstractInterpreter.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -262,8 +262,8 @@ class AbstractInterpreter: AllStatic {
 #endif
 
   // Local values relative to locals[n]
-  static int  local_offset_in_bytes(int n) {
-    return ((frame::interpreter_frame_expression_stack_direction() * n) * stackElementSize);
+  static int local_offset_in_bytes(int n) {
+    return -n * stackElementSize;
   }
 
   // access to stacked values according to type:

src/hotspot/share/runtime/frame.cpp

@@ -500,23 +500,16 @@ intptr_t* frame::interpreter_frame_local_at(int index) const {
 }
 
 intptr_t* frame::interpreter_frame_expression_stack_at(jint offset) const {
-  const int i = offset * interpreter_frame_expression_stack_direction();
-  const int n = i * Interpreter::stackElementWords;
-  return &(interpreter_frame_expression_stack()[n]);
+  const int n = offset * Interpreter::stackElementWords;
+  return interpreter_frame_expression_stack() - n;
 }
 
 jint frame::interpreter_frame_expression_stack_size() const {
   // Number of elements on the interpreter expression stack
   // Callers should span by stackElementWords
   int element_size = Interpreter::stackElementWords;
-  size_t stack_size = 0;
-  if (frame::interpreter_frame_expression_stack_direction() < 0) {
-    stack_size = (interpreter_frame_expression_stack() -
-                  interpreter_frame_tos_address() + 1)/element_size;
-  } else {
-    stack_size = (interpreter_frame_tos_address() -
-                  interpreter_frame_expression_stack() + 1)/element_size;
-  }
+  size_t stack_size = (interpreter_frame_expression_stack() -
+                        interpreter_frame_tos_address() + 1)/element_size;
   assert(stack_size <= (size_t)max_jint, "stack size too big");
   return (jint)stack_size;
 }
@@ -791,14 +784,8 @@ class InterpreterFrameClosure : public OffsetClosure {
     } else {
       addr = (oop*) _fr->interpreter_frame_expression_stack_at((offset - _max_locals));
       // In case of exceptions, the expression stack is invalid and the esp will be reset to express
-      // this condition. Therefore, we call f only if addr is 'inside' the stack (i.e., addr >= esp for Intel).
-      bool in_stack;
-      if (frame::interpreter_frame_expression_stack_direction() > 0) {
-        in_stack = (intptr_t*)addr <= _fr->interpreter_frame_tos_address();
-      } else {
-        in_stack = (intptr_t*)addr >= _fr->interpreter_frame_tos_address();
-      }
-      if (in_stack) {
+      // this condition. Therefore, we call f only if addr is 'inside' the stack (i.e., addr >= esp).
+      if ((intptr_t*)addr >= _fr->interpreter_frame_tos_address()) {
         _f->do_oop(addr);
       }
     }

src/hotspot/share/runtime/vframe.cpp

@@ -318,13 +318,9 @@ static StackValue* create_stack_value_from_oop_map(const InterpreterOopMap& oop_
 static bool is_in_expression_stack(const frame& fr, const intptr_t* const addr) {
   assert(addr != nullptr, "invariant");
 
-  // Ensure to be 'inside' the expression stack (i.e., addr >= sp for Intel).
+  // Ensure to be 'inside' the expression stack (i.e., addr >= sp).
   // In case of exceptions, the expression stack is invalid and the sp
   // will be reset to express this condition.
-  if (frame::interpreter_frame_expression_stack_direction() > 0) {
-    return addr <= fr.interpreter_frame_tos_address();
-  }
-
   return addr >= fr.interpreter_frame_tos_address();
 }
 

src/hotspot/share/runtime/vframeArray.cpp

@@ -473,12 +473,7 @@ void vframeArrayElement::unpack_on_stack(int caller_actual_parameters,
              "expression stack size should have been extended");
 #endif // ASSERT
       int top_element = iframe()->interpreter_frame_expression_stack_size()-1;
-      intptr_t* base;
-      if (frame::interpreter_frame_expression_stack_direction() < 0) {
-        base = iframe()->interpreter_frame_expression_stack_at(top_element);
-      } else {
-        base = iframe()->interpreter_frame_expression_stack();
-      }
+      intptr_t* base = iframe()->interpreter_frame_expression_stack_at(top_element);
       Copy::conjoint_jbytes(saved_args,
                             base,
                             popframe_preserved_args_size_in_bytes);