X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=includes%2FCmm.h;h=4cfb432811f6da84f719f06b150772e1454da34c;hb=ffa600f6702f215dd132b8b1b8a1f07d3a9e3ea6;hp=cecf92640bf807cfa8b19b5273c440ee3ed664d0;hpb=6015a94f9108a502150565577b66c23650796639;p=ghc-hetmet.git

diff --git a/includes/Cmm.h b/includes/Cmm.h
index cecf926..4cfb432 100644
--- a/includes/Cmm.h
+++ b/includes/Cmm.h
@@ -102,18 +102,8 @@
 #endif
 
 /*
- * The RTS must UNTAG a pointer before dereferencing it.
- * The use of UNTAG follows the following rules of thumb:
- *
- * - Any pointer might be tagged.
- * - Except the pointers that are passed in R1 to RTS functions.
- * - R1 is also untagged when entering constructor code.
- * 
- * TODO:
- *
- * - Remove redundancies of tagging and untagging in code generation.
- * - Optimize getTag or dataToTag# ?
- *
+ * The RTS must sometimes UNTAG a pointer before dereferencing it.
+ * See the wiki page Commentary/Rts/HaskellExecution/PointerTagging 
  */
 #define TAG_MASK ((1 << TAG_BITS) - 1)
 #define UNTAG(p) (p & ~TAG_MASK)
@@ -407,9 +397,12 @@
 #define BITMAP_BITS(bitmap) ((bitmap) >> BITMAP_BITS_SHIFT)
 
 /* Debugging macros */
-#define LOOKS_LIKE_INFO_PTR(p)				\
-   ((p) != NULL && 					\
-     (TO_W_(%INFO_TYPE(%STD_INFO(p))) != INVALID_OBJECT) &&	\
+#define LOOKS_LIKE_INFO_PTR(p)                                  \
+   ((p) != NULL &&                                              \
+    LOOKS_LIKE_INFO_PTR_NOT_NULL(p))
+
+#define LOOKS_LIKE_INFO_PTR_NOT_NULL(p)                         \
+   ( (TO_W_(%INFO_TYPE(%STD_INFO(p))) != INVALID_OBJECT) &&     \
      (TO_W_(%INFO_TYPE(%STD_INFO(p))) <  N_CLOSURE_TYPES))
 
 #define LOOKS_LIKE_CLOSURE_PTR(p) (LOOKS_LIKE_INFO_PTR(GET_INFO(UNTAG(p))))
@@ -571,9 +564,13 @@
   W_[free] = p;								\
   bdescr_free(__bd) = free + WDS(1);
 
-#define recordMutable(p, regs)						\
-      W_ __p;								\
-      __p = p;								\
-      recordMutableCap(__p, TO_W_(bdescr_gen_no(Bdescr(__p))), regs)
+#define recordMutable(p, regs)                                  \
+      W_ __p;                                                   \
+      W_ __bd;                                                  \
+      W_ __gen;                                                 \
+      __p = p;                                                  \
+      __bd = Bdescr(__p);                                       \
+      __gen = TO_W_(bdescr_gen_no(__bd));                       \
+      if (__gen > 0) { recordMutableCap(__p, __gen, regs); }
 
 #endif /* CMM_H */