Unroll more StringDictionary lookup probes both for positive and negative dictionary lookups.

src/ia32/stub-cache-ia32.cc

Index: src/ia32/stub-cache-ia32.cc
diff --git a/src/ia32/stub-cache-ia32.cc b/src/ia32/stub-cache-ia32.cc
index c6251157f28c373895feecbaba9e609023203ef9..92f26fc27b3cf9e7ee17bd6b7aaadddf14b40484 100644
--- a/src/ia32/stub-cache-ia32.cc
+++ b/src/ia32/stub-cache-ia32.cc
@@ -118,7 +118,6 @@ static void GenerateDictionaryNegativeLookup(MacroAssembler* masm,
   __ IncrementCounter(counters->negative_lookups(), 1);
   __ IncrementCounter(counters->negative_lookups_miss(), 1);
 
-  Label done;
   __ mov(r0, FieldOperand(receiver, HeapObject::kMapOffset));
 
   const int kInterceptorOrAccessCheckNeededMask =
@@ -154,6 +153,8 @@ static void GenerateDictionaryNegativeLookup(MacroAssembler* masm,
       StringDictionary::kHeaderSize +
       StringDictionary::kElementsStartIndex * kPointerSize;
 
+  Label done;
+
   // If names of slots in range from 1 to kProbes - 1 for the hash value are
   // not equal to the name and kProbes-th slot is not used (its name is the
   // undefined value), it guarantees the hash table doesn't contain the
@@ -167,37 +168,40 @@ static void GenerateDictionaryNegativeLookup(MacroAssembler* masm,
     __ mov(index, FieldOperand(properties, kCapacityOffset));
     __ dec(index);
     __ and_(Operand(index),
-            Immediate(Smi::FromInt(name->Hash() +
+           Immediate(Smi::FromInt(name->Hash() +

[Mads Ager (chromium), 2011/05/04 15:03:21]

Accidental edit?

                                    StringDictionary::GetProbeOffset(i))));
 
     // Scale the index by multiplying by the entry size.
     ASSERT(StringDictionary::kEntrySize == 3);
     __ lea(index, Operand(index, index, times_2, 0));  // index *= 3.
-
     Register entity_name = r1;
     // Having undefined at this place means the name is not contained.
     ASSERT_EQ(kSmiTagSize, 1);
     __ mov(entity_name, Operand(properties, index, times_half_pointer_size,
                                 kElementsStartOffset - kHeapObjectTag));
     __ cmp(entity_name, masm->isolate()->factory()->undefined_value());
-    if (i != kProbes - 1) {
-      __ j(equal, &done, taken);
-
-      // Stop if found the property.
-      __ cmp(entity_name, Handle<String>(name));
-      __ j(equal, miss_label, not_taken);
-
-      // Check if the entry name is not a symbol.
-      __ mov(entity_name, FieldOperand(entity_name, HeapObject::kMapOffset));
-      __ test_b(FieldOperand(entity_name, Map::kInstanceTypeOffset),
-                kIsSymbolMask);
-      __ j(zero, miss_label, not_taken);
-    } else {
-      // Give up probing if still not found the undefined value.
-      __ j(not_equal, miss_label, not_taken);
-    }
-  }
-
+    __ j(equal, &done, taken);
+
+    // Stop if found the property.
+    __ cmp(entity_name, Handle<String>(name));
+    __ j(equal, miss_label, not_taken);
+
+    // Check if the entry name is not a symbol.
+    __ mov(entity_name, FieldOperand(entity_name, HeapObject::kMapOffset));
+    __ test_b(FieldOperand(entity_name, Map::kInstanceTypeOffset),
+              kIsSymbolMask);
+    __ j(zero, miss_label, not_taken);
+  }
+
+  StringDictionaryLookupStub stub(properties,
+                                  r1,
+                                  r1,
+                                  StringDictionaryLookupStub::NEGATIVE_LOOKUP);
+  __ push(Immediate(Handle<Object>(name)));
+  __ push(Immediate(name->Hash()));
+  __ CallStub(&stub);
+  __ test(r1, Operand(r1));
+  __ j(not_zero, miss_label);
   __ bind(&done);
   __ DecrementCounter(counters->negative_lookups_miss(), 1);
 }