8365229: ARM32: c2i_no_clinit_check_entry assert failed after JDK-8364269

Reviewed-by: kvn, adinn, bulasevich, phh

src/hotspot/cpu/zero/sharedRuntime_zero.cpp

@@ -56,11 +56,11 @@ void SharedRuntime::generate_i2c2i_adapters(MacroAssembler *masm,
                                             const BasicType *sig_bt,
                                             const VMRegPair *regs,
                                             AdapterHandlerEntry* handler) {
+  // VM expects i2c entry to be always filled. The rest can be unset.
   handler->set_entry_points(CAST_FROM_FN_PTR(address,zero_null_code_stub),
-                            CAST_FROM_FN_PTR(address,zero_null_code_stub),
-                            CAST_FROM_FN_PTR(address,zero_null_code_stub),
+                            nullptr,
+                            nullptr,
                             nullptr);
-  return;
 }
 
 nmethod *SharedRuntime::generate_native_wrapper(MacroAssembler *masm,

src/hotspot/share/code/codeBlob.cpp

@@ -450,8 +450,10 @@ AdapterBlob::AdapterBlob(int size, CodeBuffer* cb, int entry_offset[AdapterBlob:
   BufferBlob("I2C/C2I adapters", CodeBlobKind::Adapter, cb, size, sizeof(AdapterBlob)) {
   assert(entry_offset[0] == 0, "sanity check");
   for (int i = 1; i < AdapterBlob::ENTRY_COUNT; i++) {
-    assert(entry_offset[i] > 0 && entry_offset[i] < cb->insts()->size(),
-           "invalid entry offset 0x%x", entry_offset[i]);
+    // The entry is within the adapter blob or unset.
+    assert((entry_offset[i] > 0 && entry_offset[i] < cb->insts()->size()) ||
+           (entry_offset[i] == -1),
+           "invalid entry offset[%d] = 0x%x", i, entry_offset[i]);
   }
   _c2i_offset = entry_offset[1];
   _c2i_unverified_offset = entry_offset[2];

src/hotspot/share/runtime/sharedRuntime.cpp

@@ -2778,7 +2778,12 @@ AdapterBlob* AdapterHandlerLibrary::lookup_aot_cache(AdapterHandlerEntry* handle
     adapter_blob->get_offsets(offsets);
     address i2c_entry = adapter_blob->content_begin();
     assert(offsets[0] == 0, "sanity check");
-    handler->set_entry_points(i2c_entry, i2c_entry + offsets[1], i2c_entry + offsets[2], i2c_entry + offsets[3]);
+    handler->set_entry_points(
+      i2c_entry,
+      (offsets[1] != -1) ? (i2c_entry + offsets[1]) : nullptr,
+      (offsets[2] != -1) ? (i2c_entry + offsets[2]) : nullptr,
+      (offsets[3] != -1) ? (i2c_entry + offsets[3]) : nullptr
+    );
   }
   return adapter_blob;
 }
@@ -2842,9 +2847,12 @@ bool AdapterHandlerLibrary::generate_adapter_code(AdapterBlob*& adapter_blob,
   assert(AdapterBlob::ENTRY_COUNT == 4, "sanity");
   address i2c_entry = handler->get_i2c_entry();
   entry_offset[0] = 0; // i2c_entry offset
-  entry_offset[1] = handler->get_c2i_entry() - i2c_entry;
-  entry_offset[2] = handler->get_c2i_unverified_entry() - i2c_entry;
-  entry_offset[3] = handler->get_c2i_no_clinit_check_entry() - i2c_entry;
+  entry_offset[1] = (handler->get_c2i_entry() != nullptr) ?
+                    (handler->get_c2i_entry() - i2c_entry) : -1;
+  entry_offset[2] = (handler->get_c2i_unverified_entry() != nullptr) ?
+                    (handler->get_c2i_unverified_entry() - i2c_entry) : -1;
+  entry_offset[3] = (handler->get_c2i_no_clinit_check_entry() != nullptr) ?
+                    (handler->get_c2i_no_clinit_check_entry() - i2c_entry) : -1;
 
   adapter_blob = AdapterBlob::create(&buffer, entry_offset);
   if (adapter_blob == nullptr) {