From: ager@chromium.org <ager@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Mon, 8 Sep 2008 06:17:38 +0000 (+0000)
Subject: Avoid string conversion when comparing Smis during sorting.
X-Git-Tag: upstream/4.7.83~25442
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e0b50dde0e28249f3038f79b3e70f49519e8fb34;p=platform%2Fupstream%2Fv8.git

Avoid string conversion when comparing Smis during sorting.

Avoid runtime calls for trivial object equality checks.

Minor style cleanups.



git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@185 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---

diff --git a/src/array.js b/src/array.js
index 105f41ba2..b532ef14d 100644
--- a/src/array.js
+++ b/src/array.js
@@ -219,8 +219,9 @@ function SmartMove(array, start_i, del_count, len, num_additional_args) {
         // %HasLocalProperty would be the appropriate test.  We follow
         // KJS in consulting the prototype.
         var current = array[j];
-        if (!IS_UNDEFINED(current) || j in array)
+        if (!IS_UNDEFINED(current) || j in array) {
           new_array[j] = current;
+        }
         j++;
       }
       j = start_i + del_count;
@@ -230,8 +231,9 @@ function SmartMove(array, start_i, del_count, len, num_additional_args) {
         // appropriate test.  We follow KJS in consulting the
         // prototype.
         var current = array[j];
-        if (!IS_UNDEFINED(current) || j in array)
+        if (!IS_UNDEFINED(current) || j in array) {
           new_array[j - del_count + num_additional_args] = current;
+        }
         j++;
       }
     } else {
@@ -241,16 +243,18 @@ function SmartMove(array, start_i, del_count, len, num_additional_args) {
           // %HasLocalProperty would be the appropriate test.  We follow
           // KJS in consulting the prototype.
           var current = array[key];
-          if (!IS_UNDEFINED(current) || key in array)
+          if (!IS_UNDEFINED(current) || key in array) {
             new_array[key] = current;
+          }
         } else if (key >= start_i + del_count) {
           // ECMA-262 15.4.4.12 lines 24 and 41.  The spec could also
           // be interpreted such that %HasLocalProperty would be the
           // appropriate test.  We follow KJS in consulting the
           // prototype.
           var current = array[key];
-          if (!IS_UNDEFINED(current) || key in array)
+          if (!IS_UNDEFINED(current) || key in array) {
             new_array[key - del_count + num_additional_args] = current;
+          }
         }
       }
     }
@@ -658,6 +662,9 @@ function ArraySort(comparefn) {
     if (IS_FUNCTION(comparefn)) {
       return comparefn.call(null, x, y);
     }
+    if (%_IsSmi(x) && %_IsSmi(y)) {
+      return %SmiLexicographicCompare(x, y);
+    }
     x = ToString(x);
     y = ToString(y);
     if (x == y) return 0;
@@ -677,7 +684,7 @@ function ArraySort(comparefn) {
       var parent_index = ((child_index + 1) >> 1) - 1;
       var parent_value = this[parent_index], child_value = this[child_index];
       if (Compare(parent_value, child_value) < 0) {
-        this[parent_index] = child_value; 
+        this[parent_index] = child_value;
         this[child_index] = parent_value;
       } else {
         break;
diff --git a/src/codegen-arm.cc b/src/codegen-arm.cc
index c4d3f3867..2ab308e8a 100644
--- a/src/codegen-arm.cc
+++ b/src/codegen-arm.cc
@@ -295,6 +295,8 @@ class ArmCodeGenerator: public CodeGenerator {
   virtual void GenerateSetValueOf(ZoneList<Expression*>* args);
 
   virtual void GenerateFastCharCodeAt(ZoneList<Expression*>* args);
+
+  virtual void GenerateObjectEquals(ZoneList<Expression*>* args);
 };
 
 
@@ -3998,6 +4000,19 @@ void ArmCodeGenerator::GenerateArgumentsAccess(ZoneList<Expression*>* args) {
 }
 
 
+void ArmCodeGenerator::GenerateObjectEquals(ZoneList<Expression*>* args) {
+  ASSERT(args->length() == 2);
+
+  // Load the two objects into registers and perform the comparison.
+  Load(args->at(0));
+  Load(args->at(1));
+  __ pop(r0);
+  __ pop(r1);
+  __ cmp(r0, Operand(r1));
+  cc_reg_ = eq;
+}
+
+
 void ArmCodeGenerator::GenerateShiftDownAndTailCall(
     ZoneList<Expression*>* args) {
   // r0 = number of arguments
diff --git a/src/codegen-ia32.cc b/src/codegen-ia32.cc
index 6d38136be..e181686fd 100644
--- a/src/codegen-ia32.cc
+++ b/src/codegen-ia32.cc
@@ -314,6 +314,8 @@ class Ia32CodeGenerator: public CodeGenerator {
   virtual void GenerateSetValueOf(ZoneList<Expression*>* args);
 
   virtual void GenerateFastCharCodeAt(ZoneList<Expression*>* args);
+
+  virtual void GenerateObjectEquals(ZoneList<Expression*>* args);
 };
 
 
@@ -4264,6 +4266,18 @@ void Ia32CodeGenerator::GenerateArgumentsAccess(ZoneList<Expression*>* args) {
 }
 
 
+void Ia32CodeGenerator::GenerateObjectEquals(ZoneList<Expression*>* args) {
+  ASSERT(args->length() == 2);
+
+  // Load the two objects into registers and perform the comparison.
+  Load(args->at(0));
+  Load(args->at(1));
+  __ pop(eax);
+  __ pop(ecx);
+  __ cmp(eax, Operand(ecx));
+  cc_reg_ = equal;
+}
+
 
 void Ia32CodeGenerator::VisitCallRuntime(CallRuntime* node) {
   if (CheckForInlineRuntimeCall(node)) return;
diff --git a/src/codegen.cc b/src/codegen.cc
index 14ab511bd..87b4159c2 100644
--- a/src/codegen.cc
+++ b/src/codegen.cc
@@ -256,7 +256,9 @@ bool CodeGenerator::CheckForInlineRuntimeCall(CallRuntime* node) {
     {&v8::internal::CodeGenerator::GenerateSetValueOf,
      "_SetValueOf"},
     {&v8::internal::CodeGenerator::GenerateFastCharCodeAt,
-     "_FastCharCodeAt"}
+     "_FastCharCodeAt"},
+    {&v8::internal::CodeGenerator::GenerateObjectEquals,
+     "_ObjectEquals"}
   };
   if (node->name()->length() > 0 && node->name()->Get(0) == '_') {
     for (unsigned i = 0;
diff --git a/src/codegen.h b/src/codegen.h
index 9833445c8..e6bc211ff 100644
--- a/src/codegen.h
+++ b/src/codegen.h
@@ -173,6 +173,9 @@ class CodeGenerator: public Visitor {
   // Fast support for charCodeAt(n).
   virtual void GenerateFastCharCodeAt(ZoneList<Expression*>* args) = 0;
 
+  // Fast support for object equality testing.
+  virtual void GenerateObjectEquals(ZoneList<Expression*>* args) = 0;
+
  private:
   bool is_eval_;  // Tells whether code is generated for eval.
   Handle<Script> script_;
diff --git a/src/mirror-delay.js b/src/mirror-delay.js
index c1ffed1b0..62ede24cc 100644
--- a/src/mirror-delay.js
+++ b/src/mirror-delay.js
@@ -708,7 +708,7 @@ ObjectMirror.prototype.lookupProperty = function(value) {
     // Skip properties which are defined through assessors.
     var property = properties[i];
     if (property.propertyType() != PropertyType.Callbacks) {
-      if (%ObjectEquals(property.value_, value.value_) == 0) {
+      if (%_ObjectEquals(property.value_, value.value_)) {
         return property;
       }
     }
@@ -728,12 +728,12 @@ ObjectMirror.prototype.lookupProperty = function(value) {
 ObjectMirror.prototype.referencedBy = function(opt_max_instances) {
   // Find all objects constructed from this function.
   var result = %DebugReferencedBy(this.value_, Mirror.prototype, opt_max_instances || 0);
-    
+
   // Make mirrors for all the instances found.
   for (var i = 0; i < result.length; i++) {
     result[i] = MakeMirror(result[i]);
   }
-    
+
   return result;
 };
 
diff --git a/src/runtime.cc b/src/runtime.cc
index cad5d23f3..870e8b72d 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -2309,14 +2309,6 @@ static Object* Runtime_NumberSar(Arguments args) {
 }
 
 
-static Object* Runtime_ObjectEquals(Arguments args) {
-  NoHandleAllocation ha;
-  ASSERT(args.length() == 2);
-
-  return Smi::FromInt(args[0] == args[1] ? EQUAL : NOT_EQUAL);
-}
-
-
 static Object* Runtime_NumberEquals(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
@@ -2387,6 +2379,66 @@ static Object* Runtime_NumberCompare(Arguments args) {
 }
 
 
+// Compare two Smis as if they were converted to strings and then
+// compared lexicographically.
+static Object* Runtime_SmiLexicographicCompare(Arguments args) {
+  NoHandleAllocation ha;
+  ASSERT(args.length() == 2);
+
+  // Arrays for the individual characters of the two Smis.  Smis are
+  // 31 bit integers and 10 decimal digits are therefore enough.
+  static int x_elms[10];
+  static int y_elms[10];
+
+  // Extract the integer values from the Smis.
+  CONVERT_CHECKED(Smi, x, args[0]);
+  CONVERT_CHECKED(Smi, y, args[1]);
+  int x_value = x->value();
+  int y_value = y->value();
+
+  // If the integers are equal so are the string representations.
+  if (x_value == y_value) return Smi::FromInt(EQUAL);
+
+  // If one of the integers are zero the normal integer order is the
+  // same as the lexicographic order of the string representations.
+  if (x_value == 0 || y_value == 0) return Smi::FromInt(x_value - y_value);
+
+  // If only one of the intergers is negative the negative number is
+  // smallest because the char code of '-' is less than the char code
+  // of any digit.  Otherwise, we make both values positive.
+  if (x_value < 0 || y_value < 0) {
+    if (y_value >= 0) return Smi::FromInt(LESS);
+    if (x_value >= 0) return Smi::FromInt(GREATER);
+    x_value = -x_value;
+    y_value = -y_value;
+  }
+
+  // Convert the integers to arrays of their decimal digits.
+  int x_index = 0;
+  int y_index = 0;
+  while (x_value > 0) {
+    x_elms[x_index++] = x_value % 10;
+    x_value /= 10;
+  }
+  while (y_value > 0) {
+    y_elms[y_index++] = y_value % 10;
+    y_value /= 10;
+  }
+
+  // Loop through the arrays of decimal digits finding the first place
+  // where they differ.
+  while (--x_index >= 0 && --y_index >= 0) {
+    int diff = x_elms[x_index] - y_elms[y_index];
+    if (diff != 0) return Smi::FromInt(diff);
+  }
+
+  // If one array is a suffix of the other array, the longest array is
+  // the representation of the largest of the Smis in the
+  // lexicographic ordering.
+  return Smi::FromInt(x_index - y_index);
+}
+
+
 static Object* Runtime_StringCompare(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
diff --git a/src/runtime.h b/src/runtime.h
index d56e0b364..afb5179ff 100644
--- a/src/runtime.h
+++ b/src/runtime.h
@@ -106,11 +106,11 @@ namespace v8 { namespace internal {
   F(NumberSar, 2) \
   \
   /* Comparisons */ \
-  F(ObjectEquals, 2) \
   F(NumberEquals, 2) \
   F(StringEquals, 2) \
   \
   F(NumberCompare, 3) \
+  F(SmiLexicographicCompare, 2) \
   F(StringCompare, 2) \
   \
   /* Math */ \
diff --git a/src/runtime.js b/src/runtime.js
index 78c20c1c3..68deb86d9 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -57,13 +57,13 @@ function EQUALS(y) {
   // NOTE: We use iteration instead of recursion, because it is
   // difficult to call EQUALS with the correct setting of 'this' in
   // an efficient way.
-  
+
   while (true) {
-    
+
     if (IS_NUMBER(x)) {
       if (y == null) return 1;  // not equal
       return %NumberEquals(x, %ToNumber(y));
-      
+
     } else if (IS_STRING(x)) {
       if (IS_STRING(y)) return %StringEquals(x, y);
       if (IS_NUMBER(y)) return %NumberEquals(%ToNumber(x), y);
@@ -72,19 +72,25 @@ function EQUALS(y) {
       y = %ToPrimitive(y, NO_HINT);
 
     } else if (IS_BOOLEAN(x)) {
-      if (IS_BOOLEAN(y)) return %ObjectEquals(x, y);
+      if (IS_BOOLEAN(y)) {
+        return %_ObjectEquals(x, y) ? 0 : 1;
+      }
       if (y == null) return 1;  // not equal
       return %NumberEquals(%ToNumber(x), %ToNumber(y));
-      
+
     } else if (x == null) {
       // NOTE: This checks for both null and undefined.
       return (y == null) ? 0 : 1;
-      
+
     } else {
-      if (IS_OBJECT(y)) return %ObjectEquals(x, y);
-      if (IS_FUNCTION(y)) return %ObjectEquals(x, y);
+      if (IS_OBJECT(y)) {
+        return %_ObjectEquals(x, y) ? 0 : 1;
+      }
+      if (IS_FUNCTION(y)) {
+        return %_ObjectEquals(x, y) ? 0 : 1;
+      }
       x = %ToPrimitive(x, NO_HINT);
-      
+
     }
   }
 };
@@ -96,23 +102,23 @@ function STRICT_EQUALS(x) {
     if (!IS_NUMBER(x)) return 1;  // not equal
     return %NumberEquals(this, x);
   }
-  
+
   if (IS_STRING(this)) {
     if (!IS_STRING(x)) return 1;  // not equal
     return %StringEquals(this, x);
   }
-  
+
   if (IS_BOOLEAN(this)) {
     if (!IS_BOOLEAN(x)) return 1;  // not equal
     if (this) return x ? 0 : 1;
     else return x ? 1 : 0;
   }
-  
+
   if (IS_UNDEFINED(this)) {  // both undefined and undetectable
     return IS_UNDEFINED(x) ? 0 : 1;
   }
-  
-  return %ObjectEquals(this, x);
+
+  return %_ObjectEquals(this, x) ? 0 : 1;
 };
 
 
@@ -123,7 +129,7 @@ function COMPARE(x, ncr) {
   if (IS_NUMBER(this) && IS_NUMBER(x)) {
     return %NumberCompare(this, x, ncr);
   }
-  
+
   var a = %ToPrimitive(this, NUMBER_HINT);
   var b = %ToPrimitive(x, NUMBER_HINT);
   if (IS_STRING(a) && IS_STRING(b)) {
diff --git a/test/mjsunit/array-sort.js b/test/mjsunit/array-sort.js
index ca49b8c93..768a3983f 100644
--- a/test/mjsunit/array-sort.js
+++ b/test/mjsunit/array-sort.js
@@ -30,13 +30,29 @@
 // Test counter-intuitive default number sorting.
 function TestNumberSort() {
   var a = [ 200, 45, 7 ];
-  // Default sort calls toString on each element and orders
+
+  // Default sort converts each element to string and orders
   // lexicographically.
   a.sort();
   assertArrayEquals([ 200, 45, 7 ], a);
   // Sort numbers by value using a compare functions.
   a.sort(function(x, y) { return x - y; });
   assertArrayEquals([ 7, 45, 200 ], a);
+
+  // Default sort on negative numbers.
+  a = [-12345,-123,-1234,-123456];
+  a.sort();
+  assertArrayEquals([-123,-1234,-12345,-123456], a);
+
+  // Default sort on negative and non-negative numbers.
+  a = [123456,0,-12345,-123,123,1234,-1234,0,12345,-123456];
+  a.sort();
+  assertArrayEquals([-123,-1234,-12345,-123456,0,0,123,1234,12345,123456], a);
+
+  // Default sort on Smis and non-Smis.
+  a = [1000000000, 10000000000, 1000000001, -1000000000, -10000000000, -1000000001];
+  a.sort();
+  assertArrayEquals([-1000000000, -10000000000, -1000000001, 1000000000, 10000000000, 1000000001], a);
 }
 
 TestNumberSort();