[Interpreter] Introduce IncStub and DecStub.

src/code-stubs.cc

Index: src/code-stubs.cc
diff --git a/src/code-stubs.cc b/src/code-stubs.cc
index f594b0f9e266955659e86e464cb6a4568de2c083..8ea9185337a1a6156502dc16dfe3f165a9462562 100644
--- a/src/code-stubs.cc
+++ b/src/code-stubs.cc
@@ -1608,6 +1608,170 @@ void BitwiseXorStub::GenerateAssembly(CodeStubAssembler* assembler) const {
   assembler->Return(result);
 }
 
+void IncStub::GenerateAssembly(CodeStubAssembler* assembler) const {
+  typedef CodeStubAssembler::Label Label;
+  typedef compiler::Node Node;
+  typedef CodeStubAssembler::Variable Variable;
+
+  Node* context = assembler->Parameter(1);
+
+  // Shared entry for floating point increment.
+  Label do_finc(assembler);
+  Variable var_finc_value(assembler, MachineRepresentation::kFloat64);
+
+  // We might need to try again due to ToNumber conversion.
+  Variable value_var(assembler, MachineRepresentation::kTagged);
+  Variable* start_vars[1] = {&value_var};
+  Label start(assembler, 1, start_vars);

[Benedikt Meurer, 2016/04/21 11:37:35]

You can just use Label start(assembler, &value_var);

[rmcilroy, 2016/04/21 13:55:31]

I'm sure I tried this first and it didn't work, but works this time :). Done.

+  value_var.Bind(assembler->Parameter(0));
+  assembler->Goto(&start);
+  assembler->Bind(&start);
+  {
+    Node* value = value_var.value();
+
+    Label if_issmi(assembler), if_isnotsmi(assembler);
+    assembler->Branch(assembler->WordIsSmi(value), &if_issmi, &if_isnotsmi);
+
+    assembler->Bind(&if_issmi);
+    {
+      // Try fast Smi addition first.
+      Node* one = assembler->SmiConstant(Smi::FromInt(1));
+      Node* pair = assembler->SmiAddWithOverflow(value, one);
+      Node* overflow = assembler->Projection(1, pair);
+
+      // Check if the Smi additon overflowed.
+      Label if_overflow(assembler), if_notoverflow(assembler);
+      assembler->Branch(overflow, &if_overflow, &if_notoverflow);
+
+      assembler->Bind(&if_notoverflow);
+      assembler->Return(assembler->Projection(0, pair));
+
+      assembler->Bind(&if_overflow);
+      {
+        var_finc_value.Bind(assembler->SmiToFloat64(value));
+        assembler->Goto(&do_finc);
+      }
+    }
+
+    assembler->Bind(&if_isnotsmi);
+    {
+      // Check if the value is a HeapNumber.
+      Label if_valueisnumber(assembler),
+          if_valuenotnumber(assembler, Label::kDeferred);
+      Node* value_map = assembler->LoadMap(value);
+      Node* number_map = assembler->HeapNumberMapConstant();
+      assembler->Branch(assembler->WordEqual(value_map, number_map),
+                        &if_valueisnumber, &if_valuenotnumber);
+
+      assembler->Bind(&if_valueisnumber);
+      {
+        // Load the HeapNumber value.
+        var_finc_value.Bind(assembler->LoadHeapNumberValue(value));
+        assembler->Goto(&do_finc);
+      }
+
+      assembler->Bind(&if_valuenotnumber);
+      {
+        // Convert to a Number first and try again.
+        Callable callable = CodeFactory::NonNumberToNumber(isolate());
+        value_var.Bind(assembler->CallStub(callable, context, value));
+        assembler->Goto(&start);
+      }
+    }
+  }
+
+  assembler->Bind(&do_finc);
+  {
+    Node* finc_value = var_finc_value.value();
+    Node* one = assembler->Float64Constant(1.0);
+    Node* finc_result = assembler->Float64Add(finc_value, one);
+    Node* result = assembler->ChangeFloat64ToTagged(finc_result);
+    assembler->Return(result);
+  }
+}
+
+void DecStub::GenerateAssembly(CodeStubAssembler* assembler) const {
+  typedef CodeStubAssembler::Label Label;
+  typedef compiler::Node Node;
+  typedef CodeStubAssembler::Variable Variable;
+
+  Node* context = assembler->Parameter(1);
+
+  // Shared entry for floating point decrement.
+  Label do_fdec(assembler);
+  Variable var_fdec_value(assembler, MachineRepresentation::kFloat64);
+
+  // We might need to try again due to ToNumber conversion.
+  Variable value_var(assembler, MachineRepresentation::kTagged);
+  Variable* start_vars[1] = {&value_var};
+  Label start(assembler, 1, start_vars);

[Benedikt Meurer, 2016/04/21 11:37:35]

You can just use Label start(assembler, &value_var);

[rmcilroy, 2016/04/21 13:55:31]

Done.

+  value_var.Bind(assembler->Parameter(0));
+  assembler->Goto(&start);
+  assembler->Bind(&start);
+  {
+    Node* value = value_var.value();
+
+    Label if_issmi(assembler), if_isnotsmi(assembler);
+    assembler->Branch(assembler->WordIsSmi(value), &if_issmi, &if_isnotsmi);
+
+    assembler->Bind(&if_issmi);
+    {
+      // Try fast Smi subtraction first.
+      Node* one = assembler->SmiConstant(Smi::FromInt(1));
+      Node* pair = assembler->SmiSubWithOverflow(value, one);
+      Node* overflow = assembler->Projection(1, pair);
+
+      // Check if the Smi subtraction overflowed.
+      Label if_overflow(assembler), if_notoverflow(assembler);
+      assembler->Branch(overflow, &if_overflow, &if_notoverflow);
+
+      assembler->Bind(&if_notoverflow);
+      assembler->Return(assembler->Projection(0, pair));
+
+      assembler->Bind(&if_overflow);
+      {
+        var_fdec_value.Bind(assembler->SmiToFloat64(value));
+        assembler->Goto(&do_fdec);
+      }
+    }
+
+    assembler->Bind(&if_isnotsmi);
+    {
+      // Check if the value is a HeapNumber.
+      Label if_valueisnumber(assembler),
+          if_valuenotnumber(assembler, Label::kDeferred);
+      Node* value_map = assembler->LoadMap(value);
+      Node* number_map = assembler->HeapNumberMapConstant();
+      assembler->Branch(assembler->WordEqual(value_map, number_map),
+                        &if_valueisnumber, &if_valuenotnumber);
+
+      assembler->Bind(&if_valueisnumber);
+      {
+        // Load the HeapNumber value.
+        var_fdec_value.Bind(assembler->LoadHeapNumberValue(value));
+        assembler->Goto(&do_fdec);
+      }
+
+      assembler->Bind(&if_valuenotnumber);
+      {
+        // Convert to a Number first and try again.
+        Callable callable = CodeFactory::NonNumberToNumber(isolate());
+        value_var.Bind(assembler->CallStub(callable, context, value));
+        assembler->Goto(&start);
+      }
+    }
+  }
+
+  assembler->Bind(&do_fdec);
+  {
+    Node* fdec_value = var_fdec_value.value();
+    Node* one = assembler->Float64Constant(1.0);
+    Node* fdec_result = assembler->Float64Sub(fdec_value, one);
+    Node* result = assembler->ChangeFloat64ToTagged(fdec_result);
+    assembler->Return(result);
+  }
+}
+
 namespace {
 
 enum RelationalComparisonMode {