Make x87 stack tracking more robust and avoid spilling

src/ia32/assembler-ia32.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 212 matching lines @@
 #define xmm1 (static_cast<const XMMRegister&>(double_register_1))
 #define xmm2 (static_cast<const XMMRegister&>(double_register_2))
 #define xmm3 (static_cast<const XMMRegister&>(double_register_3))
 #define xmm4 (static_cast<const XMMRegister&>(double_register_4))
 #define xmm5 (static_cast<const XMMRegister&>(double_register_5))
 #define xmm6 (static_cast<const XMMRegister&>(double_register_6))
 #define xmm7 (static_cast<const XMMRegister&>(double_register_7))
 
 
 struct X87Register : IntelDoubleRegister {
-  static const int kNumAllocatableRegisters = 5;
+  static const int kNumAllocatableRegisters = 2;
   static const int kNumRegisters = 5;
 
   bool is(X87Register reg) const {
     return code_ == reg.code_;
   }
 
   static const char* AllocationIndexToString(int index) {
     ASSERT(index >= 0 && index < kNumAllocatableRegisters);
     const char* const names[] = {
       "stX_0", "stX_1", "stX_2", "stX_3", "stX_4"
@@ skipping 987 matching lines @@
  private:
   Assembler* assembler_;
 #ifdef DEBUG
   int space_before_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_ASSEMBLER_IA32_H_