Avoid bit fields in `mrb_value`; ref b2c3d88f

The changes at b2c3d88f were inappropriate because the memory layout of bit
fields are implementation defined. Therefor, I fixed it not to use bit
fields.

3 files changed, 68 insertions, 55 deletions

diff --git a/include/mruby/boxing_nan.h b/include/mruby/boxing_nan.h
index 4b47a3f17..af598e34e 100644
--- a/include/mruby/boxing_nan.h
+++ b/include/mruby/boxing_nan.h
@@ -21,12 +21,6 @@
 
 #define MRB_FIXNUM_SHIFT 0
 
-#ifdef MRB_ENDIAN_BIG
-#define MRB_ENDIAN_LOHI(a,b) a b
-#else
-#define MRB_ENDIAN_LOHI(a,b) b a
-#endif
-
 /* value representation by nan-boxing:
  *   float : FFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFF
  *   object: 111111111111TTTT TTPPPPPPPPPPPPPP PPPPPPPPPPPPPPPP PPPPPPPPPPPPPPPP
diff --git a/include/mruby/boxing_word.h b/include/mruby/boxing_word.h
index 9e4ee456f..de48278da 100644
--- a/include/mruby/boxing_word.h
+++ b/include/mruby/boxing_word.h
@@ -37,29 +37,39 @@ enum mrb_special_consts {
 };
 
 #define MRB_IMMEDIATE_MASK  0x07
+#define MRB_FIXNUM_MASK     0x01
+#define MRB_SYMBOL_MASK     0x0f
 #define MRB_FIXNUM_FLAG     0x01
 #define MRB_SYMBOL_FLAG     0x0e
-#define MRB_SPECIAL_SHIFT   8
+#define MRB_SYMBOL_SHIFT    8
 
-#if defined(MRB_64BIT)
+#ifdef MRB_64BIT
 #define MRB_SYMBOL_BITSIZE  (sizeof(mrb_sym) * CHAR_BIT)
 #define MRB_SYMBOL_MAX      UINT32_MAX
 #else
-#define MRB_SYMBOL_BITSIZE  (sizeof(mrb_sym) * CHAR_BIT - MRB_SPECIAL_SHIFT)
-#define MRB_SYMBOL_MAX      (UINT32_MAX >> MRB_SPECIAL_SHIFT)
+#define MRB_SYMBOL_BITSIZE  (sizeof(mrb_sym) * CHAR_BIT - MRB_SYMBOL_SHIFT)
+#define MRB_SYMBOL_MAX      (UINT32_MAX >> MRB_SYMBOL_SHIFT)
 #endif
 
+#define BOXWORD_SHIFT_VALUE(o,n,t) \
+  ((((t)(o).w)) >> MRB_##n##_SHIFT)
+#define BOXWORD_SET_SHIFT_VALUE(o,n,v) \
+  ((o).w = (((unsigned long)(v)) << MRB_##n##_SHIFT) | MRB_##n##_FLAG)
+#define BOXWORD_SHIFT_VALUE_P(o,n) \
+  (((o).w & MRB_##n##_MASK) == MRB_##n##_FLAG)
+
 typedef union mrb_value {
   union {
     void *p;
+#ifdef MRB_64BIT
+    /* use struct to avoid bit shift. */
     struct {
-      unsigned int i_flag : MRB_FIXNUM_SHIFT;
-      mrb_int i : (MRB_INT_BIT - MRB_FIXNUM_SHIFT);
-    };
-    struct {
-      unsigned int sym_flag : MRB_SPECIAL_SHIFT;
-      mrb_sym sym : MRB_SYMBOL_BITSIZE;
+      MRB_ENDIAN_LOHI(
+        mrb_sym sym;
+        ,uint32_t sym_flag;
+      )
     };
+#endif
     struct RBasic *bp;
 #ifndef MRB_WITHOUT_FLOAT
     struct RFloat *fp;
@@ -84,8 +94,42 @@ MRB_API mrb_value mrb_word_boxing_float_pool(struct mrb_state*, mrb_float);
 #ifndef MRB_WITHOUT_FLOAT
 #define mrb_float(o)   (o).value.fp->f
 #endif
-#define mrb_fixnum(o)  ((mrb_int)(o).value.i)
+#define mrb_fixnum(o)  BOXWORD_SHIFT_VALUE(o, FIXNUM, mrb_int)
+#ifdef MRB_64BIT
 #define mrb_symbol(o)  (o).value.sym
+#else
+#define mrb_symbol(o)  BOXWORD_SHIFT_VALUE(o, SYMBOL, mrb_sym)
+#endif
+#define mrb_bool(o)    ((o).w != MRB_Qnil && (o).w != MRB_Qfalse)
+
+#define mrb_immediate_p(o) ((o).w & MRB_IMMEDIATE_MASK || (o).w == MRB_Qnil)
+#define mrb_fixnum_p(o) BOXWORD_SHIFT_VALUE_P(o, FIXNUM)
+#ifdef MRB_64BIT
+#define mrb_symbol_p(o) ((o).value.sym_flag == MRB_SYMBOL_FLAG)
+#else
+#define mrb_symbol_p(o) BOXWORD_SHIFT_VALUE_P(o, SYMBOL)
+#endif
+#define mrb_undef_p(o) ((o).w == MRB_Qundef)
+#define mrb_nil_p(o)  ((o).w == MRB_Qnil)
+#define mrb_false_p(o) ((o).w == MRB_Qfalse)
+#define mrb_true_p(o)  ((o).w == MRB_Qtrue)
+
+#ifndef MRB_WITHOUT_FLOAT
+#define SET_FLOAT_VALUE(mrb,r,v) ((r) = mrb_word_boxing_float_value(mrb, v))
+#endif
+#define SET_CPTR_VALUE(mrb,r,v) ((r) = mrb_word_boxing_cptr_value(mrb, v))
+#define SET_UNDEF_VALUE(r) ((r).w = MRB_Qundef)
+#define SET_NIL_VALUE(r) ((r).w = MRB_Qnil)
+#define SET_FALSE_VALUE(r) ((r).w = MRB_Qfalse)
+#define SET_TRUE_VALUE(r) ((r).w = MRB_Qtrue)
+#define SET_BOOL_VALUE(r,b) ((b) ? SET_TRUE_VALUE(r) : SET_FALSE_VALUE(r))
+#define SET_INT_VALUE(r,n) BOXWORD_SET_SHIFT_VALUE(r, FIXNUM, n)
+#ifdef MRB_64BIT
+#define SET_SYM_VALUE(r,v) ((r).value.sym = v, (r).value.sym_flag = MRB_SYMBOL_FLAG)
+#else
+#define SET_SYM_VALUE(r,n) BOXWORD_SET_SHIFT_VALUE(r, SYMBOL, n)
+#endif
+#define SET_OBJ_VALUE(r,v) ((r).value.p = v)
 
 MRB_INLINE enum mrb_vtype
 mrb_type(mrb_value o)
@@ -99,45 +143,13 @@ mrb_type(mrb_value o)
   case MRB_Qundef:
     return MRB_TT_UNDEF;
   }
-  if (o.value.i_flag == MRB_FIXNUM_FLAG) {
+  if (mrb_fixnum_p(o)) {
     return MRB_TT_FIXNUM;
   }
-  if (o.value.sym_flag == MRB_SYMBOL_FLAG) {
+  if (mrb_symbol_p(o)) {
     return MRB_TT_SYMBOL;
   }
   return o.value.bp->tt;
 }
 
-#define mrb_bool(o)    ((o).w != MRB_Qnil && (o).w != MRB_Qfalse)
-#define mrb_immediate_p(o) ((o).w & MRB_IMMEDIATE_MASK || (o).w == MRB_Qnil)
-#define mrb_fixnum_p(o) ((o).value.i_flag == MRB_FIXNUM_FLAG)
-#define mrb_undef_p(o) ((o).w == MRB_Qundef)
-#define mrb_nil_p(o)  ((o).w == MRB_Qnil)
-#define mrb_false_p(o) ((o).w == MRB_Qfalse)
-#define mrb_true_p(o)  ((o).w == MRB_Qtrue)
-
-#ifndef MRB_WITHOUT_FLOAT
-#define SET_FLOAT_VALUE(mrb,r,v) ((r) = mrb_word_boxing_float_value(mrb, v))
-#endif
-#define SET_CPTR_VALUE(mrb,r,v) ((r) = mrb_word_boxing_cptr_value(mrb, v))
-#define SET_UNDEF_VALUE(r) ((r).w = MRB_Qundef)
-#define SET_NIL_VALUE(r) ((r).w = MRB_Qnil)
-#define SET_FALSE_VALUE(r) ((r).w = MRB_Qfalse)
-#define SET_TRUE_VALUE(r) ((r).w = MRB_Qtrue)
-#define SET_BOOL_VALUE(r,b) ((b) ? SET_TRUE_VALUE(r) : SET_FALSE_VALUE(r))
-#define SET_INT_VALUE(r,n) do {                                             \
-  (r).w = 0;                                                                \
-  (r).value.i_flag = MRB_FIXNUM_FLAG;                                       \
-  (r).value.i = (n);                                                        \
-} while (0)
-#define SET_SYM_VALUE(r,v)  do {                                            \
-  (r).w = 0;                                                                \
-  (r).value.sym_flag = MRB_SYMBOL_FLAG;                                     \
-  (r).value.sym = (v);                                                      \
-} while (0)
-#define SET_OBJ_VALUE(r,v) do {                                             \
-  (r).w = 0;                                                                \
-  (r).value.p = (v);                                                        \
-} while (0)
-
 #endif  /* MRUBY_BOXING_WORD_H */
diff --git a/include/mruby/value.h b/include/mruby/value.h
index d2b85078e..52ce93d58 100644
--- a/include/mruby/value.h
+++ b/include/mruby/value.h
@@ -17,7 +17,7 @@ MRB_BEGIN_DECL
 /**
  * mruby Symbol.
  * @class mrb_sym
- * 
+ *
  * You can create an mrb_sym by simply using mrb_str_intern() or mrb_intern_cstr()
  */
 typedef uint32_t mrb_sym;
@@ -25,10 +25,10 @@ typedef uint32_t mrb_sym;
 /**
  * mruby Boolean.
  * @class mrb_bool
- * 
+ *
  *
  * Used internally to represent boolean. Can be TRUE or FALSE.
- * Not to be confused with Ruby's boolean classes, which can be 
+ * Not to be confused with Ruby's boolean classes, which can be
  * obtained using mrb_false_value() and mrb_true_value()
  */
 typedef uint8_t mrb_bool;
@@ -78,6 +78,11 @@ struct mrb_state;
 # define MRB_PRIx PRIx32
 #endif
 
+#ifdef MRB_ENDIAN_BIG
+# define MRB_ENDIAN_LOHI(a,b) a b
+#else
+# define MRB_ENDIAN_LOHI(a,b) b a
+#endif
 
 #ifndef MRB_WITHOUT_FLOAT
 MRB_API double mrb_float_read(const char*, char**);
@@ -169,6 +174,9 @@ typedef void mrb_value;
 #ifndef mrb_fixnum_p
 #define mrb_fixnum_p(o) (mrb_type(o) == MRB_TT_FIXNUM)
 #endif
+#ifndef mrb_symbol_p
+#define mrb_symbol_p(o) (mrb_type(o) == MRB_TT_SYMBOL)
+#endif
 #ifndef mrb_undef_p
 #define mrb_undef_p(o) (mrb_type(o) == MRB_TT_UNDEF)
 #endif
@@ -191,7 +199,6 @@ typedef void mrb_value;
 #ifndef MRB_WITHOUT_FLOAT
 #define mrb_float_p(o) (mrb_type(o) == MRB_TT_FLOAT)
 #endif
-#define mrb_symbol_p(o) (mrb_type(o) == MRB_TT_SYMBOL)
 #define mrb_array_p(o) (mrb_type(o) == MRB_TT_ARRAY)
 #define mrb_string_p(o) (mrb_type(o) == MRB_TT_STRING)
 #define mrb_hash_p(o) (mrb_type(o) == MRB_TT_HASH)