src/hotspot/cpu/arm/templateInterpreterGenerator_arm.cpp

rev 49887 : 8201786: Modularize interpreter GC barriers: leftovers for ARM32
Reviewed-by: XXX

@@ -850,36 +850,22 @@
 //
 // (*) - AArch64 only
 //
 
 address TemplateInterpreterGenerator::generate_Reference_get_entry(void) {
-#if INCLUDE_ALL_GCS
-  if (UseG1GC) {
     // Code: _aload_0, _getfield, _areturn
     // parameter size = 1
     //
     // The code that gets generated by this routine is split into 2 parts:
-    //    1. The "intrinsified" code for G1 (or any SATB based GC),
+  //    1. The "intrinsified" code performing an ON_WEAK_OOP_REF load,
     //    2. The slow path - which is an expansion of the regular method entry.
     //
     // Notes:-
-    // * In the G1 code we do not check whether we need to block for
-    //   a safepoint. If G1 is enabled then we must execute the specialized
-    //   code for Reference.get (except when the Reference object is null)
-    //   so that we can log the value in the referent field with an SATB
-    //   update buffer.
-    //   If the code for the getfield template is modified so that the
-    //   G1 pre-barrier code is executed when the current method is
-    //   Reference.get() then going through the normal method entry
-    //   will be fine.
-    // * The G1 code can, however, check the receiver object (the instance
-    //   of java.lang.Reference) and jump to the slow path if null. If the
-    //   Reference object is null then we obviously cannot fetch the referent
-    //   and so we don't need to call the G1 pre-barrier. Thus we can use the
-    //   regular method entry code to generate the NPE.
-    //
-    // This code is based on generate_accessor_enty.
+  // * An intrinsic is always executed, where an ON_WEAK_OOP_REF load is performed.
+  // * We may jump to the slow path iff the receiver is null. If the
+  //   Reference object is null then we no longer perform an ON_WEAK_OOP_REF load
+  //   Thus we can use the regular method entry code to generate the NPE.
     //
     // Rmethod: Method*
     // Rthread: thread
     // Rsender_sp: sender sp, must be preserved for slow path, set SP to it on fast path
     // Rparams: parameters

@@ -896,38 +882,25 @@
     // Check if local 0 != NULL
     // If the receiver is null then it is OK to jump to the slow path.
     __ ldr(Rthis, Address(Rparams));
     __ cbz(Rthis, slow_path);
 
-    // Generate the G1 pre-barrier code to log the value of
-    // the referent field in an SATB buffer.
-
-    // Load the value of the referent field.
-    __ load_heap_oop(R0, Address(Rthis, referent_offset));
-
     // Preserve LR
     __ mov(Rret_addr, LR);
 
-    __ g1_write_barrier_pre(noreg,   // store_addr
-                            noreg,   // new_val
-                            R0,      // pre_val
-                            Rtemp,   // tmp1
-                            R1_tmp); // tmp2
+  // Load the value of the referent field.
+  const Address field_address(Rthis, referent_offset);
+  __ load_heap_oop(R0, field_address, R0, Rtemp, R1_tmp);
 
     // _areturn
     __ mov(SP, Rsender_sp);
     __ ret(Rret_addr);
 
     // generate a vanilla interpreter entry as the slow path
     __ bind(slow_path);
     __ jump_to_entry(Interpreter::entry_for_kind(Interpreter::zerolocals));
     return entry;
-  }
-#endif // INCLUDE_ALL_GCS
-
-  // If G1 is not enabled then attempt to go through the normal entry point
-  return NULL;
 }
 
 // Not supported
 address TemplateInterpreterGenerator::generate_CRC32_update_entry() { return NULL; }
 address TemplateInterpreterGenerator::generate_CRC32_updateBytes_entry(AbstractInterpreter::MethodKind kind) { return NULL; }