boxing_nan.h: refactor NaN Boxing.

Preparation for:

* 64 bit integer with NaN Boxing
* Favor pointer NaN Boxing

include/mruby/boxing_nan.h

@@ -24,13 +24,21 @@
 #define MRB_FIXNUM_MIN INT32_MIN
 #define MRB_FIXNUM_MAX INT32_MAX
 
+enum mrb_nanbox_tt_inline {
+  MRB_NANBOX_TT_OBJECT = 1,
+  MRB_NANBOX_TT_INTEGER,
+  MRB_NANBOX_TT_SYMBOL,
+  MRB_NANBOX_TT_POINTER,
+  MRB_NANBOX_TT_MISC,
+};
+
 /* value representation by nan-boxing:
  *   float : FFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFF
- *   object: 111111111111TTTT TTPPPPPPPPPPPPPP PPPPPPPPPPPPPPPP PPPPPPPPPPPPPPPP
- *   int   : 1111111111110001 0000000000000000 IIIIIIIIIIIIIIII IIIIIIIIIIIIIIII
- *   sym   : 1111111111110001 0100000000000000 SSSSSSSSSSSSSSSS SSSSSSSSSSSSSSSS
- * In order to get enough bit size to save TT, all pointers are shifted 2 bits
- * in the right direction. Also, TTTTTT is the mrb_vtype + 1;
+ *   object: 1111111111110001 PPPPPPPPPPPPPPPP PPPPPPPPPPPPPPPP PPPPPPPPPPPPPPPP
+ *   int   : 1111111111110010 0000000000000000 IIIIIIIIIIIIIIII IIIIIIIIIIIIIIII
+ *   sym   : 1111111111110011 0000000000000000 SSSSSSSSSSSSSSSS SSSSSSSSSSSSSSSS
+ *   ptr   : 1111111111110100 0000000000000000 SSSSSSSSSSSSSSSS SSSSSSSSSSSSSSSS
+ *   misc  : 1111111111110101 0000000000000000 0000000000000000 TTTTTT000000MMMM
  */
 typedef struct mrb_value {
   uint64_t u;
@@ -54,77 +62,74 @@ union mrb_value_ {
   mrb_value value;
 };
 
-mrb_static_assert1(sizeof(mrb_value) == sizeof(union mrb_value_));
+mrb_static_assert(sizeof(mrb_value) == sizeof(union mrb_value_));
 
-static inline union mrb_value_
-mrb_val_union(mrb_value v)
+static inline mrb_float
+mrb_float(mrb_value v)
 {
-  union mrb_value_ x;
-  x.value = v;
-  return x;
+  union {
+    mrb_float f;
+    uint64_t u;
+  } x;
+  x.u = v.u;
+  return x.f;
 }
 
-#define mrb_tt(o)       ((enum mrb_vtype)((mrb_val_union(o).ttt & 0xfc000)>>14)-1)
-#define mrb_type(o)     (enum mrb_vtype)((uint32_t)0xfff00000 < mrb_val_union(o).ttt ? mrb_tt(o) : MRB_TT_FLOAT)
-#define mrb_float(o)    mrb_val_union(o).f
-#define mrb_fixnum(o)   ((mrb_int)mrb_val_union(o).i)
-#define mrb_integer(o)  mrb_fixnum(o)
-#define mrb_symbol(o)   ((mrb_sym)mrb_val_union(o).i)
-
-#ifdef MRB_64BIT
-#define mrb_ptr(o)      ((void*)((((uintptr_t)0x3fffffffffff)&((uintptr_t)(mrb_val_union(o).p)))<<2))
-#define mrb_cptr(o)     (((struct RCptr*)mrb_ptr(o))->p)
-#define NANBOX_SHIFT_LONG_POINTER(v) (((uintptr_t)(v)>>34)&0x3fff)
-#else
-#define mrb_ptr(o)      ((void*)mrb_val_union(o).i)
-#define mrb_cptr(o)     mrb_ptr(o)
-#define NANBOX_SHIFT_LONG_POINTER(v) 0
-#endif
-
-#define NANBOX_SET_VALUE(o, tt, attr, v) do { \
-  union mrb_value_ mrb_value_union_variable; \
-  mrb_value_union_variable.attr = (v);\
-  mrb_value_union_variable.ttt = 0xfff00000 | (((tt)+1)<<14);\
-  o = mrb_value_union_variable.value;\
-} while (0)
-
-#ifdef MRB_64BIT
-#define NANBOX_SET_OBJ_VALUE(o, tt, v) do {\
-  union mrb_value_ mrb_value_union_variable;\
-  mrb_value_union_variable.p = (void*)((uintptr_t)(v)>>2);\
-  mrb_value_union_variable.ttt = (0xfff00000|(((tt)+1)<<14)|NANBOX_SHIFT_LONG_POINTER(v));\
-  o = mrb_value_union_variable.value;\
-} while (0)
-#else
-#define NANBOX_SET_OBJ_VALUE(o, tt, v) NANBOX_SET_VALUE(o, tt, i, (uint32_t)v)
-#endif
-
 #define SET_FLOAT_VALUE(mrb,r,v) do { \
-  union mrb_value_ mrb_value_union_variable; \
+  union { \
+    mrb_float f; \
+    uint64_t u; \
+  } float_uint_union; \
   if ((v) != (v)) { /* NaN */ \
-    mrb_value_union_variable.ttt = 0x7ff80000; \
-    mrb_value_union_variable.i = 0; \
+    float_uint_union.u = 0x7ff8000000000000UL; \
   } \
   else { \
-    mrb_value_union_variable.f = (v); \
+    float_uint_union.f = (v); \
   } \
-  r = mrb_value_union_variable.value; \
+  r.u = float_uint_union.u; \
 } while(0)
 
-#define SET_NIL_VALUE(r) NANBOX_SET_VALUE(r, MRB_TT_FALSE, i, 0)
-#define SET_FALSE_VALUE(r) NANBOX_SET_VALUE(r, MRB_TT_FALSE, i, 1)
-#define SET_TRUE_VALUE(r) NANBOX_SET_VALUE(r, MRB_TT_TRUE, i, 1)
-#define SET_BOOL_VALUE(r,b) NANBOX_SET_VALUE(r, b ? MRB_TT_TRUE : MRB_TT_FALSE, i, 1)
-#define SET_INT_VALUE(mrb, r,n) NANBOX_SET_VALUE(r, MRB_TT_INTEGER, i, (uint32_t)(n))
-#define SET_FIXNUM_VALUE(r,n) NANBOX_SET_VALUE(r, MRB_TT_INTEGER, i, (uint32_t)(n))
-#define SET_SYM_VALUE(r,v) NANBOX_SET_VALUE(r, MRB_TT_SYMBOL, i, (uint32_t)(v))
-#define SET_OBJ_VALUE(r,v) NANBOX_SET_OBJ_VALUE(r, (((struct RObject*)(v))->tt), (v))
-#ifdef MRB_64BIT
-MRB_API mrb_value mrb_nan_boxing_cptr_value(struct mrb_state*, void*);
-#define SET_CPTR_VALUE(mrb,r,v) ((r) = mrb_nan_boxing_cptr_value(mrb, v))
-#else
-#define SET_CPTR_VALUE(mrb,r,v) NANBOX_SET_VALUE(r, MRB_TT_CPTR, p, v)
-#endif
-#define SET_UNDEF_VALUE(r) NANBOX_SET_VALUE(r, MRB_TT_UNDEF, i, 0)
+#define NANBOX_SET_VALUE(o, tt, v) do { \
+  (o).u = ((0xfff0|(tt))<<48) | (v).u; \
+} while (0)
+
+MRB_INLINE enum mrb_vtype
+mrb_type(mrb_value o)
+{
+  if ((o.u >> 52) == 0xfff) return MRB_TT_FLOAT;
+  switch ((o.u >> 48) & 7) {
+  case MRB_NANBOX_TT_OBJECT: {
+    uintptr_t u = o.u & ~((~0)<<48);
+    return ((struct RBasic *)u)->tt;
+  }
+  case MRB_NANBOX_TT_INTEGER:
+    return MRB_TT_INTEGER;
+  case MRB_NANBOX_TT_SYMBOL:
+    return MRB_TT_SYMBOL;
+  case MRB_NANBOX_TT_POINTER:
+    return MRB_TT_CPTR;
+  case MRB_NANBOX_TT_MISC:
+    return (enum mrb_vtype)(o.u >> 5) & 0x1f;
+  default:
+    return MRB_TT_FLOAT;
+  }
+}
+
+#define mrb_fixnum(o)   ((mrb_int)((uintptr_t)0xffffffff)&((o).u))
+#define mrb_integer(o)  mrb_fixnum(o)
+#define mrb_symbol(o)   ((mrb_sym)((uintptr_t)0xffffffff)&((o).u))
+#define mrb_ptr(o)      ((void*)(((uintptr_t)0xfffffffffff)&((o).u)))
+#define mrb_cptr(o)     mrb_ptr(o)
+
+#define SET_NIL_VALUE(r) NANBOX_SET_MISC_VALUE(r, MRB_TT_FALSE, 0)
+#define SET_FALSE_VALUE(r) NANBOX_SET_MISC_VALUE(r, MRB_TT_FALSE, 1)
+#define SET_TRUE_VALUE(r) NANBOX_SET_MISC_VALUE(r, MRB_TT_TRUE, 1)
+#define SET_BOOL_VALUE(r,b) NANBOX_SET_MISC_VALUE(r, b ? MRB_TT_TRUE : MRB_TT_FALSE, 1)
+#define SET_INT_VALUE(mrb,r,n) SET_FIXNUM_VALUE(r,n)
+#define SET_FIXNUM_VALUE(r,n) NANBOX_SET_VALUE(r, MRB_NANBOX_TT_INTEGER, (uint32_t)(n))
+#define SET_SYM_VALUE(r,v) NANBOX_SET_VALUE(r, MRB_NANBOX_TT_SYMBOL, (uint32_t)(v))
+#define SET_OBJ_VALUE(r,v) NANBOX_SET_VALUE(o, MRB_NANBOT_TT_OBJECT, v)
+#define SET_CPTR_VALUE(mrb,r,v) NANBOX_SET_VALUE(o, MRB_NANBOT_TT_POINTER, v)
+#define SET_UNDEF_VALUE(r) NANBOX_SET_MISC_VALUE(r, MRB_TT_UNDEF, 4)
 
 #endif  /* MRUBY_BOXING_NAN_H */