Version 3.0.8

Exposed heap size limit to the heap statistics gathered by the GetHeapStatistics API. 

Wrapped external pointers more carefully (issue 1037).

Hardened the implementation of error objects to avoid setters intercepting the properties set then throwing an error.

Avoided trashing the FPSCR when calculating Math.floor on ARM.

Performance improvements on the IA32 platform.


git-svn-id: http://v8.googlecode.com/svn/trunk@6346 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
diff --git a/include/v8.h b/include/v8.h
index 883bfad..7d18107 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -2515,6 +2515,7 @@
   size_t total_heap_size() { return total_heap_size_; }
   size_t total_heap_size_executable() { return total_heap_size_executable_; }
   size_t used_heap_size() { return used_heap_size_; }
+  size_t heap_size_limit() { return heap_size_limit_; }
 
  private:
   void set_total_heap_size(size_t size) { total_heap_size_ = size; }
@@ -2522,10 +2523,12 @@
     total_heap_size_executable_ = size;
   }
   void set_used_heap_size(size_t size) { used_heap_size_ = size; }
+  void set_heap_size_limit(size_t size) { heap_size_limit_ = size; }
 
   size_t total_heap_size_;
   size_t total_heap_size_executable_;
   size_t used_heap_size_;
+  size_t heap_size_limit_;
 
   friend class V8;
 };
@@ -3350,10 +3353,10 @@
 const int kSmiTagSize = 1;
 const intptr_t kSmiTagMask = (1 << kSmiTagSize) - 1;
 
-template <size_t ptr_size> struct SmiConstants;
+template <size_t ptr_size> struct SmiTagging;
 
 // Smi constants for 32-bit systems.
-template <> struct SmiConstants<4> {
+template <> struct SmiTagging<4> {
   static const int kSmiShiftSize = 0;
   static const int kSmiValueSize = 31;
   static inline int SmiToInt(internal::Object* value) {
@@ -3361,10 +3364,15 @@
     // Throw away top 32 bits and shift down (requires >> to be sign extending).
     return static_cast<int>(reinterpret_cast<intptr_t>(value)) >> shift_bits;
   }
+
+  // For 32-bit systems any 2 bytes aligned pointer can be encoded as smi
+  // with a plain reinterpret_cast.
+  static const intptr_t kEncodablePointerMask = 0x1;
+  static const int kPointerToSmiShift = 0;
 };
 
 // Smi constants for 64-bit systems.
-template <> struct SmiConstants<8> {
+template <> struct SmiTagging<8> {
   static const int kSmiShiftSize = 31;
   static const int kSmiValueSize = 32;
   static inline int SmiToInt(internal::Object* value) {
@@ -3372,10 +3380,26 @@
     // Shift down and throw away top 32 bits.
     return static_cast<int>(reinterpret_cast<intptr_t>(value) >> shift_bits);
   }
+
+  // To maximize the range of pointers that can be encoded
+  // in the available 32 bits, we require them to be 8 bytes aligned.
+  // This gives 2 ^ (32 + 3) = 32G address space covered.
+  // It might be not enough to cover stack allocated objects on some platforms.
+  static const int kPointerAlignment = 3;
+
+  static const intptr_t kEncodablePointerMask =
+      ~(intptr_t(0xffffffff) << kPointerAlignment);
+
+  static const int kPointerToSmiShift =
+      kSmiTagSize + kSmiShiftSize - kPointerAlignment;
 };
 
-const int kSmiShiftSize = SmiConstants<kApiPointerSize>::kSmiShiftSize;
-const int kSmiValueSize = SmiConstants<kApiPointerSize>::kSmiValueSize;
+typedef SmiTagging<kApiPointerSize> PlatformSmiTagging;
+const int kSmiShiftSize = PlatformSmiTagging::kSmiShiftSize;
+const int kSmiValueSize = PlatformSmiTagging::kSmiValueSize;
+const intptr_t kEncodablePointerMask =
+    PlatformSmiTagging::kEncodablePointerMask;
+const int kPointerToSmiShift = PlatformSmiTagging::kPointerToSmiShift;
 
 template <size_t ptr_size> struct InternalConstants;
 
@@ -3423,7 +3447,7 @@
   }
 
   static inline int SmiValue(internal::Object* value) {
-    return SmiConstants<kApiPointerSize>::SmiToInt(value);
+    return PlatformSmiTagging::SmiToInt(value);
   }
 
   static inline int GetInstanceType(internal::Object* obj) {
@@ -3432,9 +3456,14 @@
     return ReadField<uint8_t>(map, kMapInstanceTypeOffset);
   }
 
+  static inline void* GetExternalPointerFromSmi(internal::Object* value) {
+    const intptr_t address = reinterpret_cast<intptr_t>(value);
+    return reinterpret_cast<void*>(address >> kPointerToSmiShift);
+  }
+
   static inline void* GetExternalPointer(internal::Object* obj) {
     if (HasSmiTag(obj)) {
-      return obj;
+      return GetExternalPointerFromSmi(obj);
     } else if (GetInstanceType(obj) == kProxyType) {
       return ReadField<void*>(obj, kProxyProxyOffset);
     } else {