Refactor 'dart:profiler' UserTag API

runtime/vm/intrinsifier_mips.cc

Index: runtime/vm/intrinsifier_mips.cc
diff --git a/runtime/vm/intrinsifier_mips.cc b/runtime/vm/intrinsifier_mips.cc
index 263514dbe2f24101a093665e86f5aca7a7ce7277..ce9b0ab548147874ae96aefe4208e43fc33e8802 100644
--- a/runtime/vm/intrinsifier_mips.cc
+++ b/runtime/vm/intrinsifier_mips.cc
@@ -1783,43 +1783,39 @@ void Intrinsifier::UserTag_makeCurrent(Assembler* assembler) {
   // T1: Isolate.
   Isolate* isolate = Isolate::Current();
   __ LoadImmediate(T1, reinterpret_cast<uword>(isolate));
-  // V0: UserTag.
-  __ lw(V0, Address(SP, + 0 * kWordSize));
+  // V0: Current user tag.
+  __ lw(V0, Address(T1, Isolate::current_tag_offset()));
+  // T2: UserTag.
+  __ lw(T2, Address(SP, + 0 * kWordSize));
   // Set Isolate::current_tag_.
-  __ sw(V0, Address(T1, Isolate::current_tag_offset()));
-  // V0: UserTag's tag.
-  __ lw(V0, FieldAddress(V0, UserTag::tag_offset()));
+  __ sw(T2, Address(T1, Isolate::current_tag_offset()));
+  // T2: UserTag's tag.
+  __ lw(T2, FieldAddress(T2, UserTag::tag_offset()));
   // Set Isolate::user_tag_.
-  __ sw(V0, Address(T1, Isolate::user_tag_offset()));
-  // Set return value.
+  __ sw(T2, Address(T1, Isolate::user_tag_offset()));
   __ Ret();
-  __ delay_slot()->LoadImmediate(V0, reinterpret_cast<int32_t>(Object::null()));
+  __ delay_slot()->sw(T2, Address(T1, Isolate::user_tag_offset()));
 }
 
 
-void Intrinsifier::Profiler_getCurrentTag(Assembler* assembler) {
-  // V0: Isolate.
+void Intrinsifier::UserTag_defaultTag(Assembler* assembler) {
   Isolate* isolate = Isolate::Current();
-  __ LoadImmediate(V0, reinterpret_cast<uword>(isolate));
-  // Set return value.
+  // V0: Address of default tag.
+  __ LoadImmediate(V0,
+      reinterpret_cast<uword>(isolate->object_store()) +
+                              ObjectStore::default_tag_offset());
   __ Ret();
-  __ delay_slot()->lw(V0, Address(V0, Isolate::current_tag_offset()));
+  __ delay_slot()->lw(V0, Address(V0, 0));
 }
 
 
-void Intrinsifier::Profiler_clearCurrentTag(Assembler* assembler) {
-  // T1: Isolate.
+void Intrinsifier::Profiler_getCurrentTag(Assembler* assembler) {
+  // V0: Isolate.
   Isolate* isolate = Isolate::Current();
-  __ LoadImmediate(T1, reinterpret_cast<uword>(isolate));
-  // Set return value to Isolate::current_tag_.
-  __ lw(V0, Address(T1, Isolate::current_tag_offset()));
-  // Clear Isolate::current_tag_.
-  const int32_t raw_null = reinterpret_cast<int32_t>(UserTag::null());
-  __ LoadImmediate(T0, raw_null);
-  __ sw(T0, Address(T1, Isolate::current_tag_offset()));
-  // Clear Isolate::user_tag_.
+  __ LoadImmediate(V0, reinterpret_cast<uword>(isolate));
+  // Set return value.
   __ Ret();
-  __ delay_slot()->sw(ZR, Address(T1, Isolate::user_tag_offset()));
+  __ delay_slot()->lw(V0, Address(V0, Isolate::current_tag_offset()));
 }
 
 }  // namespace dart