Inline fast path for Array.indexOf() and Array.lastIndexOf().

src/hydrogen.cc

 // Copyright 2013 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 "hydrogen.h"
 
 #include <algorithm>
 
 #include "v8.h"
 #include "allocation-site-scopes.h"
@@ skipping 8014 matching lines @@
           if_inline.End();
         }
         if_lengthiszero.End();
       }
       result = ast_context()->IsEffect() ? graph()->GetConstant0() : Top();
       Add<HSimulate>(expr->id(), REMOVABLE_SIMULATE);
       if (!ast_context()->IsEffect()) Drop(1);
       ast_context()->ReturnValue(result);
       return true;
     }
+    case kArrayIndexOf:
+    case kArrayLastIndexOf: {
+      if (receiver_map.is_null()) return false;
+      if (receiver_map->instance_type() != JS_ARRAY_TYPE) return false;
+      ElementsKind kind = receiver_map->elements_kind();
+      if (!IsFastElementsKind(kind)) return false;
+      if (receiver_map->is_observed()) return false;
+      if (argument_count != 2) return false;
+      ASSERT(receiver_map->is_extensible());
+
+      // If there may be elements accessors in the prototype chain, the fast
+      // inlined version can't be used.
+      if (receiver_map->DictionaryElementsInPrototypeChainOnly()) return false;
+
+      // If there currently can be no elements accessors on the prototype chain,
+      // it doesn't mean that there won't be any later. Install a full prototype
+      // chain check to trap element accessors being installed on the prototype
+      // chain, which would cause elements to go to dictionary mode and result
+      // in a map change.
+      BuildCheckPrototypeMaps(
+          handle(JSObject::cast(receiver_map->prototype()), isolate()),
+          Handle<JSObject>::null());
+
+      HValue* search_element = Pop();
+      HValue* receiver = Pop();
+      HValue* index;
+      Drop(1);  // Drop function.
+
+      {

[mvstanton, 2014/06/02 11:43:44]

How about put this in a function, BuildArrayIndexOf(id, search_element,
receiver, ..)

[Benedikt Meurer, 2014/06/02 12:08:16]

Done.

+        NoObservableSideEffectsScope scope(this);
+
+        HValue* elements = AddLoadElements(receiver);
+        HValue* length = AddLoadArrayLength(receiver, kind);
+
+        HValue* initial;
+        HValue* terminating;
+        Token::Value token;
+        LoopBuilder::Direction direction;
+        if (id == kArrayIndexOf) {
+          initial = graph()->GetConstant0();
+          terminating = length;
+          token = Token::LT;
+          direction = LoopBuilder::kPostIncrement;
+        } else {
+          ASSERT_EQ(kArrayLastIndexOf, id);
+          initial = length;
+          terminating = graph()->GetConstant0();
+          token = Token::GTE;
+          direction = LoopBuilder::kPreDecrement;
+        }
+
+        if (!ast_context()->IsEffect()) Push(graph()->GetConstantMinus1());
+        if (IsFastDoubleElementsKind(kind) ||
+            IsFastSmiElementsKind(kind)) {
+          LoopBuilder loop(this, context(), direction);
+          {
+            index = loop.BeginBody(initial, terminating, token);
+            HValue* element = AddUncasted<HLoadKeyed>(
+                elements, index, static_cast<HValue*>(NULL),
+                kind, ALLOW_RETURN_HOLE);
+            IfBuilder if_issame(this);
+            if (IsFastDoubleElementsKind(kind)) {
+              if_issame.If<HCompareNumericAndBranch>(
+                  element, search_element, Token::EQ_STRICT);
+            } else {
+              if_issame.If<HCompareObjectEqAndBranch>(element, search_element);
+            }
+            if_issame.Then();
+            {
+              if (!ast_context()->IsEffect()) {
+                Drop(1);
+                Push(index);
+              }
+              loop.Break();
+            }
+            if_issame.End();
+          }
+          loop.EndBody();
+        } else {
+          IfBuilder if_isstring(this);
+          if_isstring.If<HIsStringAndBranch>(search_element);
+          if_isstring.Then();
+          {
+            LoopBuilder loop(this, context(), direction);
+            {
+              index = loop.BeginBody(initial, terminating, token);
+              HValue* element = AddUncasted<HLoadKeyed>(
+                  elements, index, static_cast<HValue*>(NULL),
+                  kind, ALLOW_RETURN_HOLE);
+              IfBuilder if_issame(this);
+              if_issame.If<HIsStringAndBranch>(element);
+              if_issame.AndIf<HStringCompareAndBranch>(
+                  element, search_element, Token::EQ_STRICT);
+              if_issame.Then();
+              {
+                if (!ast_context()->IsEffect()) {
+                  Drop(1);
+                  Push(index);
+                }
+                loop.Break();
+              }
+              if_issame.End();
+            }
+            loop.EndBody();
+          }
+          if_isstring.Else();
+          {
+            LoopBuilder loop(this, context(), direction);
+            {
+              index = loop.BeginBody(initial, terminating, token);
+              HValue* element = AddUncasted<HLoadKeyed>(
+                  elements, index, static_cast<HValue*>(NULL),
+                  kind, ALLOW_RETURN_HOLE);
+              IfBuilder if_issame(this);
+              if_issame.If<HCompareObjectEqAndBranch>(element, search_element);
+              if_issame.Then();
+              {
+                if (!ast_context()->IsEffect()) {
+                  Drop(1);
+                  Push(index);
+                }
+                loop.Break();
+              }
+              if_issame.End();
+            }
+            loop.EndBody();
+          }
+          if_isstring.End();
+        }
+      }

[mvstanton, 2014/06/02 11:43:44]

function ends here, postcondition being that in non-effect context the result is
on the top of the environment stack.

+
+      index = ast_context()->IsEffect() ? graph()->GetConstant0() : Top();
+      Add<HSimulate>(expr->id(), REMOVABLE_SIMULATE);
+      if (!ast_context()->IsEffect()) Drop(1);
+      ast_context()->ReturnValue(index);
+      return true;
+    }
     default:
       // Not yet supported for inlining.
       break;
   }
   return false;
 }
 
 
 bool HOptimizedGraphBuilder::TryInlineApiFunctionCall(Call* expr,
                                                       HValue* receiver) {
@@ skipping 3831 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal