[stubs] Introduce LeftShift, SignedRightShift and UnsignedRightShift stubs.

src/compiler/code-stub-assembler.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/code-stub-assembler.h"
 
 #include <ostream>
 
 #include "src/code-factory.h"
 #include "src/compiler/graph.h"
@@ skipping 865 matching lines @@
   Bind(&if_notoverflow);
   {
     Node* result = Projection(0, pair);
     var_result.Bind(result);
   }
   Goto(&if_join);
   Bind(&if_join);
   return var_result.value();
 }
 
+Node* CodeStubAssembler::ChangeUint32ToTagged(Node* value) {
+  Label if_overflow(this, Label::kDeferred), if_not_overflow(this),
+      if_join(this);
+  Variable var_result(this, MachineRepresentation::kTagged);
+  // If {value} > 2^31 - 1, we need to store it in a HeapNumber.
+  Branch(Int32LessThan(value, Int32Constant(0)), &if_overflow,
+         &if_not_overflow);
+  Bind(&if_not_overflow);
+  {
+    if (raw_assembler_->machine()->Is64()) {
+      var_result.Bind(SmiTag(ChangeUint32ToUint64(value)));
+    } else {
+      // If tagging {value} results in an overflow, we need to use a HeapNumber
+      // to represent it.
+      Node* pair = Int32AddWithOverflow(value, value);
+      Node* overflow = Projection(1, pair);
+      GotoIf(overflow, &if_overflow);
+
+      Node* result = Projection(0, pair);
+      var_result.Bind(result);
+    }
+  }
+  Goto(&if_join);
+
+  Bind(&if_overflow);
+  {
+    Node* float64_value = ChangeUint32ToFloat64(value);
+    var_result.Bind(AllocateHeapNumberWithValue(float64_value));
+  }
+  Goto(&if_join);
+
+  Bind(&if_join);
+  return var_result.value();
+}
+
 Node* CodeStubAssembler::TruncateTaggedToFloat64(Node* context, Node* value) {
   // We might need to loop once due to ToNumber conversion.
   Variable var_value(this, MachineRepresentation::kTagged),
       var_result(this, MachineRepresentation::kFloat64);
   Label loop(this, &var_value), done_loop(this, &var_result);
   var_value.Bind(value);
   Goto(&loop);
   Bind(&loop);
   {
     // Load the current {value}.
@@ skipping 818 matching lines @@
       }
     }
   }
 
   bound_ = true;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8