From 6742d62c303a26fc39c4e529008ea4fecf779ee4 Mon Sep 17 00:00:00 2001
From: "bak@chromium.org"
 <bak@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Tue, 22 Dec 2009 11:35:05 +0000
Subject: [PATCH] - Increased size of number string cache. - Change the
 instruction order for inlined allocation.

Review URL: http://codereview.chromium.org/501170

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3514 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/heap.cc                      | 25 +++++++++++++++----------
 src/heap.h                       |  2 +-
 src/ia32/macro-assembler-ia32.cc | 19 ++++++++++---------
 3 files changed, 26 insertions(+), 20 deletions(-)

diff --git a/src/heap.cc b/src/heap.cc
index f0ef70ebcc..7c7ed53ce4 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -1577,6 +1577,7 @@ bool Heap::CreateInitialObjects() {
   CreateFixedStubs();
 
   // Allocate the number->string conversion cache
+  ASSERT(IsPowerOf2(kNumberStringCacheSize));
   obj = AllocateFixedArray(kNumberStringCacheSize * 2);
   if (obj->IsFailure()) return false;
   set_number_string_cache(FixedArray::cast(obj));
@@ -1610,25 +1611,29 @@ bool Heap::CreateInitialObjects() {
 }
 
 
-static inline int double_get_hash(double d) {
+static inline int NumberStringTruncateHash(int value) {
+  return (((value >> 16) ^ value)) & (Heap::kNumberStringCacheSize - 1);
+}
+
+
+static inline int DoubleGetHash(double d) {
   DoubleRepresentation rep(d);
-  return ((static_cast<int>(rep.bits) ^ static_cast<int>(rep.bits >> 32)) &
-          (Heap::kNumberStringCacheSize - 1));
+  int value = (static_cast<int>(rep.bits) ^ static_cast<int>(rep.bits >> 32));
+  return NumberStringTruncateHash(value);
 }
 
 
-static inline int smi_get_hash(Smi* smi) {
-  return (smi->value() & (Heap::kNumberStringCacheSize - 1));
+static inline int SmiGetHash(Smi* smi) {
+  return NumberStringTruncateHash(smi->value());
 }
 
 
-
 Object* Heap::GetNumberStringCache(Object* number) {
   int hash;
   if (number->IsSmi()) {
-    hash = smi_get_hash(Smi::cast(number));
+    hash = SmiGetHash(Smi::cast(number));
   } else {
-    hash = double_get_hash(number->Number());
+    hash = DoubleGetHash(number->Number());
   }
   Object* key = number_string_cache()->get(hash * 2);
   if (key == number) {
@@ -1645,10 +1650,10 @@ Object* Heap::GetNumberStringCache(Object* number) {
 void Heap::SetNumberStringCache(Object* number, String* string) {
   int hash;
   if (number->IsSmi()) {
-    hash = smi_get_hash(Smi::cast(number));
+    hash = SmiGetHash(Smi::cast(number));
     number_string_cache()->set(hash * 2, number, SKIP_WRITE_BARRIER);
   } else {
-    hash = double_get_hash(number->Number());
+    hash = DoubleGetHash(number->Number());
     number_string_cache()->set(hash * 2, number);
   }
   number_string_cache()->set(hash * 2 + 1, string);
diff --git a/src/heap.h b/src/heap.h
index 4b580512ba..ebf5ff3f32 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -821,7 +821,7 @@ class Heap : public AllStatic {
   static void SetNumberStringCache(Object* number, String* str);
 
   // Entries in the cache.  Must be a power of 2.
-  static const int kNumberStringCacheSize = 64;
+  static const int kNumberStringCacheSize = 16*KB;
 
   // Adjusts the amount of registered external memory.
   // Returns the adjusted value.
diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index 3ecbcee812..53738bee13 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -729,13 +729,13 @@ void MacroAssembler::AllocateInNewSpace(int object_size,
   cmp(result_end, Operand::StaticVariable(new_space_allocation_limit));
   j(above, gc_required, not_taken);
 
-  // Update allocation top.
-  UpdateAllocationTopHelper(result_end, scratch);
-
   // Tag result if requested.
   if ((flags & TAG_OBJECT) != 0) {
     or_(Operand(result), Immediate(kHeapObjectTag));
   }
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
 }
 
 
@@ -759,13 +759,14 @@ void MacroAssembler::AllocateInNewSpace(int header_size,
   cmp(result_end, Operand::StaticVariable(new_space_allocation_limit));
   j(above, gc_required);
 
-  // Update allocation top.
-  UpdateAllocationTopHelper(result_end, scratch);
-
   // Tag result if requested.
   if ((flags & TAG_OBJECT) != 0) {
     or_(Operand(result), Immediate(kHeapObjectTag));
   }
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
+
 }
 
 
@@ -790,13 +791,13 @@ void MacroAssembler::AllocateInNewSpace(Register object_size,
   cmp(result_end, Operand::StaticVariable(new_space_allocation_limit));
   j(above, gc_required, not_taken);
 
-  // Update allocation top.
-  UpdateAllocationTopHelper(result_end, scratch);
-
   // Tag result if requested.
   if ((flags & TAG_OBJECT) != 0) {
     or_(Operand(result), Immediate(kHeapObjectTag));
   }
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
 }