src/hotspot/share/gc/shared/c1/modRefBarrierSetC1.cpp

@@ -20,10 +20,11 @@
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   *
   */
  
+ #include "ci/ciInlineKlass.hpp"
  #include "gc/shared/c1/modRefBarrierSetC1.hpp"
  #include "utilities/macros.hpp"
  
  #ifdef ASSERT
  #define __ gen->lir(__FILE__, __LINE__)->

@@ -34,10 +35,25 @@
  void ModRefBarrierSetC1::store_at_resolved(LIRAccess& access, LIR_Opr value) {
    DecoratorSet decorators = access.decorators();
    bool is_array = (decorators & IS_ARRAY) != 0;
    bool on_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
  
+   // Is this a flat, atomic access that might require gc barriers on oop fields?
+   ciInlineKlass* vk = access.vk();
+   if (vk != nullptr && vk->has_object_fields()) {
+     // Add pre-barriers for oop fields
+     for (int i = 0; i < vk->nof_nonstatic_fields(); i++) {
+       ciField* field = vk->nonstatic_field_at(i);
+       if (!field->type()->is_primitive_type()) {
+         int off = access.offset().opr().as_jint() + field->offset_in_bytes() - vk->payload_offset();
+         LIRAccess inner_access(access.gen(), decorators, access.base(), LIR_OprFact::intConst(off), field->type()->basic_type(), access.patch_emit_info(), access.access_emit_info());
+         pre_barrier(inner_access, resolve_address(inner_access, false),
+                     LIR_OprFact::illegalOpr /* pre_val */, inner_access.patch_emit_info());
+       }
+     }
+   }
+ 
    if (access.is_oop()) {
      pre_barrier(access, access.resolved_addr(),
                  LIR_OprFact::illegalOpr /* pre_val */, access.patch_emit_info());
    }
  

@@ -46,10 +62,35 @@
    if (access.is_oop()) {
      bool precise = is_array || on_anonymous;
      LIR_Opr post_addr = precise ? access.resolved_addr() : access.base().opr();
      post_barrier(access, post_addr, value);
    }
+ 
+   if (vk != nullptr && vk->has_object_fields()) {
+     // Add post-barriers for oop fields
+     for (int i = 0; i < vk->nof_nonstatic_fields(); i++) {
+       ciField* field = vk->nonstatic_field_at(i);
+       if (!field->type()->is_primitive_type()) {
+         int inner_off = field->offset_in_bytes() - vk->payload_offset();
+         int off = access.offset().opr().as_jint() + inner_off;
+         LIRAccess inner_access(access.gen(), decorators, access.base(), LIR_OprFact::intConst(off), field->type()->basic_type(), access.patch_emit_info(), access.access_emit_info());
+ 
+         // Shift long value to extract the narrow oop field value and zero-extend
+         LIR_Opr field_val = access.gen()->new_register(T_LONG);
+         access.gen()->lir()->unsigned_shift_right(value,
+                                                   LIR_OprFact::intConst(inner_off << LogBitsPerByte),
+                                                   field_val, LIR_Opr::illegalOpr());
+         LIR_Opr mask = access.gen()->load_immediate((julong) max_juint, T_LONG);
+         access.gen()->lir()->logical_and(field_val, mask, field_val);
+         LIR_Opr oop_val = access.gen()->new_register(T_OBJECT);
+         access.gen()->lir()->move(field_val, oop_val);
+ 
+         assert(!is_array && !on_anonymous, "not suppported");
+         post_barrier(inner_access, access.base().opr(), oop_val);
+       }
+     }
+   }
  }
  
  LIR_Opr ModRefBarrierSetC1::atomic_cmpxchg_at_resolved(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_value) {
    if (access.is_oop()) {
      pre_barrier(access, access.resolved_addr(),