Support reusable boxes for Float32x4 fields

runtime/vm/intermediate_language_mips.cc

Index: runtime/vm/intermediate_language_mips.cc
diff --git a/runtime/vm/intermediate_language_mips.cc b/runtime/vm/intermediate_language_mips.cc
index 450c24bc6e595402959ea7c1ddae95ff89f0751b..d7166389ae3b9256271f327b114750881c4e368c 100644
--- a/runtime/vm/intermediate_language_mips.cc
+++ b/runtime/vm/intermediate_language_mips.cc
@@ -1656,18 +1656,25 @@ void GuardFieldInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
 }
 
 
+bool Field::IsUnboxedField() const {
+  bool valid_class = (guarded_cid() == kDoubleCid);
+  return is_unboxing_candidate() && !is_final() && !is_nullable() &&
+         valid_class;
+}
+
+
 class StoreInstanceFieldSlowPath : public SlowPathCode {
  public:
-  StoreInstanceFieldSlowPath(StoreInstanceFieldInstr* instruction,
-                             const Class& cls)
-      : instruction_(instruction), cls_(cls) { }
+  explicit StoreInstanceFieldSlowPath(StoreInstanceFieldInstr* instruction)
+      : instruction_(instruction) { }
 
   virtual void EmitNativeCode(FlowGraphCompiler* compiler) {
     __ Comment("StoreInstanceFieldSlowPath");
-    __ Bind(entry_label());
+    __ Bind(double_entry_label());
+    const Class& cls = compiler->double_class();
     const Code& stub =
-        Code::Handle(StubCode::GetAllocationStubForClass(cls_));
-    const ExternalLabel label(cls_.ToCString(), stub.EntryPoint());
+        Code::Handle(StubCode::GetAllocationStubForClass(cls));
+    const ExternalLabel label(cls.ToCString(), stub.EntryPoint());
 
     LocationSummary* locs = instruction_->locs();
     locs->live_registers()->Remove(locs->out());
@@ -1680,12 +1687,20 @@ class StoreInstanceFieldSlowPath : public SlowPathCode {
     __ mov(locs->temp(0).reg(), V0);
     compiler->RestoreLiveRegisters(locs);
 
-    __ b(exit_label());
+    __ b(double_exit_label());
+  }
+
+  Label* double_entry_label() {
+    // Use default SlowPathCode label for double.
+    return entry_label();
+  }
+  Label* double_exit_label() {
+    // Use default SlowPathCode label for double.
+    return exit_label();
   }
 
  private:
   StoreInstanceFieldInstr* instruction_;
-  const Class& cls_;
 };
 
 
@@ -1730,24 +1745,28 @@ void StoreInstanceFieldInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
     Register temp = locs()->temp(0).reg();
     Register temp2 = locs()->temp(1).reg();
     const intptr_t cid = field().UnboxedFieldCid();
+    StoreInstanceFieldSlowPath* slow_path =
+        new StoreInstanceFieldSlowPath(this);
+    compiler->AddSlowPathCode(slow_path);
 
     if (is_initialization_) {
       const Class* cls = NULL;
+      Label* entry_label = NULL;
+      Label* exit_label = NULL;
       switch (cid) {
         case kDoubleCid:
           cls = &compiler->double_class();
+          entry_label = slow_path->double_entry_label();
+          exit_label = slow_path->double_exit_label();
           break;
         default:
           UNREACHABLE();
       }
-      StoreInstanceFieldSlowPath* slow_path =
-          new StoreInstanceFieldSlowPath(this, *cls);
-      compiler->AddSlowPathCode(slow_path);
       __ TryAllocate(*cls,
-                     slow_path->entry_label(),
+                     entry_label,
                      temp,
                      temp2);
-      __ Bind(slow_path->exit_label());
+      __ Bind(exit_label);
       __ mov(temp2, temp);
       __ StoreIntoObject(instance_reg,
                          FieldAddress(instance_reg, field().Offset()),
@@ -1797,7 +1816,7 @@ void StoreInstanceFieldInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
                       &copy_double);
 
     StoreInstanceFieldSlowPath* slow_path =
-        new StoreInstanceFieldSlowPath(this, compiler->double_class());
+        new StoreInstanceFieldSlowPath(this);
     compiler->AddSlowPathCode(slow_path);
 
     if (!compiler->is_optimizing()) {
@@ -1806,10 +1825,10 @@ void StoreInstanceFieldInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
     }
 
     __ TryAllocate(compiler->double_class(),
-                   slow_path->entry_label(),
+                   slow_path->double_entry_label(),
                    temp,
                    temp2);
-    __ Bind(slow_path->exit_label());
+    __ Bind(slow_path->double_exit_label());
     __ mov(temp2, temp);
     __ StoreIntoObject(instance_reg,
                        FieldAddress(instance_reg, field().Offset()),
@@ -1967,13 +1986,13 @@ void AllocateObjectWithBoundsCheckInstr::EmitNativeCode(
 }
 
 
-class BoxDoubleSlowPath : public SlowPathCode {
+class LoadFieldSlowPath : public SlowPathCode {
  public:
-  explicit BoxDoubleSlowPath(Instruction* instruction)
+  explicit LoadFieldSlowPath(Instruction* instruction)
       : instruction_(instruction) { }
 
   virtual void EmitNativeCode(FlowGraphCompiler* compiler) {
-    __ Comment("BoxDoubleSlowPath");
+    __ Comment("LoadFieldSlowPath");
     __ Bind(entry_label());
     const Class& double_class = compiler->double_class();
     const Code& stub =
@@ -1996,6 +2015,15 @@ class BoxDoubleSlowPath : public SlowPathCode {
     __ b(exit_label());
   }
 
+  Label* double_entry_label() {
+    // Use default SlowPathCode label for double.
+    return entry_label();
+  }
+  Label* double_exit_label() {
+    // Use default SlowPathCode label for double.
+    return exit_label();
+  }
+
  private:
   Instruction* instruction_;
 };
@@ -2048,6 +2076,8 @@ void LoadFieldInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   if (IsPotentialUnboxedLoad()) {
     Register temp = locs()->temp(1).reg();
     DRegister value = locs()->temp(0).fpu_reg();
+    LoadFieldSlowPath* slow_path = new LoadFieldSlowPath(this);
+    compiler->AddSlowPathCode(slow_path);
 
     Label load_pointer;
     Label load_double;
@@ -2067,26 +2097,26 @@ void LoadFieldInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
     // Fall through.
     __ b(&load_pointer);
 
-    __ Bind(&load_double);
+    {
+      __ Bind(&load_double);
 
-    BoxDoubleSlowPath* slow_path = new BoxDoubleSlowPath(this);
-    compiler->AddSlowPathCode(slow_path);
+      if (!compiler->is_optimizing()) {
+        locs()->live_registers()->Add(locs()->in(0));
+      }
 
-    if (!compiler->is_optimizing()) {
-      locs()->live_registers()->Add(locs()->in(0));
+      __ TryAllocate(compiler->double_class(),
+                     slow_path->double_entry_label(),
+                     result_reg,
+                     temp);
+      __ Bind(slow_path->double_exit_label());
+      __ lw(temp, FieldAddress(instance_reg, offset_in_bytes()));
+      __ LoadDFromOffset(value, temp, Double::value_offset() - kHeapObjectTag);
+      __ StoreDToOffset(value,
+                        result_reg,
+                        Double::value_offset() - kHeapObjectTag);
+      __ b(&done);
     }
 
-    __ TryAllocate(compiler->double_class(),
-                   slow_path->entry_label(),
-                   result_reg,
-                   temp);
-    __ Bind(slow_path->exit_label());
-    __ lw(temp, FieldAddress(instance_reg, offset_in_bytes()));
-    __ LoadDFromOffset(value, temp, Double::value_offset() - kHeapObjectTag);
-    __ StoreDToOffset(value,
-                      result_reg,
-                      Double::value_offset() - kHeapObjectTag);
-    __ b(&done);
     __ Bind(&load_pointer);
   }
   __ lw(result_reg, Address(instance_reg, offset_in_bytes() - kHeapObjectTag));
@@ -2935,6 +2965,40 @@ void CheckEitherNonSmiInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
 }
 
 
+class BoxDoubleSlowPath : public SlowPathCode {
+ public:
+  explicit BoxDoubleSlowPath(Instruction* instruction)
+      : instruction_(instruction) { }
+
+  virtual void EmitNativeCode(FlowGraphCompiler* compiler) {
+    __ Comment("BoxDoubleSlowPath");
+    __ Bind(entry_label());
+    const Class& double_class = compiler->double_class();
+    const Code& stub =
+        Code::Handle(StubCode::GetAllocationStubForClass(double_class));
+    const ExternalLabel label(double_class.ToCString(), stub.EntryPoint());
+
+    LocationSummary* locs = instruction_->locs();
+    locs->live_registers()->Remove(locs->out());
+
+    compiler->SaveLiveRegisters(locs);
+    compiler->GenerateCall(Scanner::kNoSourcePos,  // No token position.
+                           &label,
+                           PcDescriptors::kOther,
+                           locs);
+    if (locs->out().reg() != V0) {
+      __ mov(locs->out().reg(), V0);
+    }
+    compiler->RestoreLiveRegisters(locs);
+
+    __ b(exit_label());
+  }
+
+ private:
+  Instruction* instruction_;
+};
+
+
 LocationSummary* BoxDoubleInstr::MakeLocationSummary(bool opt) const {
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 1;