diff src/hotspot/cpu/arm/templateInterpreterGenerator_arm.cpp @ 50475:7b916885654d

8201786: Modularize interpreter GC barriers: leftovers for ARM32 Reviewed-by: enevill, eosterlund
author shade
date Wed, 02 May 2018 19:26:42 +0200
parents bdbef8638948
children 2f79462aab9b
line wrap: on
line diff
--- a/src/hotspot/cpu/arm/templateInterpreterGenerator_arm.cpp	Wed May 02 10:48:48 2018 -0700
+++ b/src/hotspot/cpu/arm/templateInterpreterGenerator_arm.cpp	Wed May 02 19:26:42 2018 +0200
@@ -852,80 +852,53 @@
 //
 
 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),
-    //    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.
-    //
-    // Rmethod: Method*
-    // Rthread: thread
-    // Rsender_sp: sender sp, must be preserved for slow path, set SP to it on fast path
-    // Rparams: parameters
+  // 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 performing an ON_WEAK_OOP_REF load,
+  //    2. The slow path - which is an expansion of the regular method entry.
+  //
+  // Notes:-
+  // * 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
 
-    address entry = __ pc();
-    Label slow_path;
-    const Register Rthis = R0;
-    const Register Rret_addr = Rtmp_save1;
-    assert_different_registers(Rthis, Rret_addr, Rsender_sp);
+  address entry = __ pc();
+  Label slow_path;
+  const Register Rthis = R0;
+  const Register Rret_addr = Rtmp_save1;
+  assert_different_registers(Rthis, Rret_addr, Rsender_sp);
 
-    const int referent_offset = java_lang_ref_Reference::referent_offset;
-    guarantee(referent_offset > 0, "referent offset not initialized");
+  const int referent_offset = java_lang_ref_Reference::referent_offset;
+  guarantee(referent_offset > 0, "referent offset not initialized");
 
-    // 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);
+  // 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.
+  // Preserve LR
+  __ mov(Rret_addr, LR);
 
-    // Load the value of the referent field.
-    __ load_heap_oop(R0, Address(Rthis, referent_offset));
+  // Load the value of the referent field.
+  const Address field_address(Rthis, referent_offset);
+  __ load_heap_oop(R0, field_address, Rtemp, R1_tmp, R2_tmp, ON_WEAK_OOP_REF);
 
-    // Preserve LR
-    __ mov(Rret_addr, LR);
+  // _areturn
+  __ mov(SP, Rsender_sp);
+  __ ret(Rret_addr);
 
-    __ g1_write_barrier_pre(noreg,   // store_addr
-                            noreg,   // new_val
-                            R0,      // pre_val
-                            Rtemp,   // tmp1
-                            R1_tmp); // tmp2
-
-    // _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;
+  // generate a vanilla interpreter entry as the slow path
+  __ bind(slow_path);
+  __ jump_to_entry(Interpreter::entry_for_kind(Interpreter::zerolocals));
+  return entry;
 }
 
 // Not supported