X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=includes%2FCmm.h;h=06a66a79ef724925a117fa5f8dd43af638409472;hp=b23a37be040e5bda37a37c90ebbde5172a00fc05;hb=176fa33f17dd78355cc572e006d2ab26898e2c69;hpb=d31dfb32ea936c22628b508c28a36c12e631430a

diff --git a/includes/Cmm.h b/includes/Cmm.h
index b23a37b..06a66a7 100644
--- a/includes/Cmm.h
+++ b/includes/Cmm.h
@@ -25,7 +25,7 @@
  *       - Hp += n  ==> Hp_adj(n)
  *       - R1.i   ==>  R1   (similarly for R1.w, R1.cl etc.)
  *       - You need to explicitly dereference variables; eg. 
- *             context_switch   ==>  CInt[context_switch]
+ *             alloc_blocks   ==>  CInt[alloc_blocks]
  *       - convert all word offsets into byte offsets:
  *         	- e ==> WDS(e)
  *       - sizeofW(StgFoo)  ==>  SIZEOF_StgFoo
@@ -88,15 +88,28 @@
 #define I16 bits16
 #define I32 bits32
 #define I64 bits64
+#define P_  gcptr
 
 #if SIZEOF_VOID_P == 4
 #define W_ bits32
+/* Maybe it's better to include MachDeps.h */
+#define TAG_BITS                2
 #elif SIZEOF_VOID_P == 8
 #define W_ bits64
+/* Maybe it's better to include MachDeps.h */
+#define TAG_BITS                3
 #else
 #error Unknown word size
 #endif
 
+/*
+ * 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)
+#define GETTAG(p) (p & TAG_MASK)
+
 #if SIZEOF_INT == 4
 #define CInt bits32
 #elif SIZEOF_INT == 8
@@ -228,12 +241,24 @@
 
    ToDo: range should end in N_CLOSURE_TYPES-1, not N_CLOSURE_TYPES,
    but switch doesn't allow us to use exprs there yet.
+
+   If R1 points to a tagged object it points either to
+   * A constructor.
+   * A function with arity <= TAG_MASK.
+   In both cases the right thing to do is to return.
+   Note: it is rather lucky that we can use the tag bits to do this
+         for both objects. Maybe it points to a brittle design?
+
+   Indirections can contain tagged pointers, so their tag is checked.
    -------------------------------------------------------------------------- */
 
 #define ENTER()						\
  again:							\
   W_ info;						\
-  info = %INFO_PTR(R1);					\
+  if (GETTAG(P1) != 0) {                                \
+      jump %ENTRY_CODE(Sp(0));				\
+  }                                                     \
+  info = %INFO_PTR(P1);					\
   switch [INVALID_OBJECT .. N_CLOSURE_TYPES]		\
          (TO_W_( %INFO_TYPE(%STD_INFO(info)) )) {	\
   case							\
@@ -243,18 +268,17 @@
     IND_OLDGEN_PERM,					\
     IND_STATIC:						\
    {							\
-      R1 = StgInd_indirectee(R1);			\
+      P1 = StgInd_indirectee(P1);			\
       goto again;					\
    }							\
   case							\
-    BCO,						\
     FUN,						\
     FUN_1_0,						\
     FUN_0_1,						\
     FUN_2_0,						\
     FUN_1_1,						\
-    FUN_0_2,						\
-    FUN_STATIC,						\
+    FUN_STATIC,                                         \
+    BCO,						\
     PAP:						\
    {							\
       jump %ENTRY_CODE(Sp(0));				\
@@ -265,6 +289,10 @@
    }							\
   }
 
+// The FUN cases almost never happen: a pointer to a non-static FUN
+// should always be tagged.  This unfortunately isn't true for the
+// interpreter right now, which leaves untagged FUNs on the stack.
+
 /* -----------------------------------------------------------------------------
    Constants.
    -------------------------------------------------------------------------- */
@@ -274,7 +302,7 @@
 #include "ClosureTypes.h"
 #include "StgFun.h"
 #include "OSThreads.h"
-#include "SMP.h"
+#include "SMPClosureOps.h"
 
 /*
  * Need MachRegs, because some of the RTS code is conditionally
@@ -370,12 +398,15 @@
 #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(p)))
+#define LOOKS_LIKE_CLOSURE_PTR(p) (LOOKS_LIKE_INFO_PTR(GET_INFO(UNTAG(p))))
 
 /*
  * The layout of the StgFunInfoExtra part of an info table changes
@@ -514,9 +545,6 @@
 #define END_TSO_QUEUE             stg_END_TSO_QUEUE_closure
 #define END_INVARIANT_CHECK_QUEUE stg_END_INVARIANT_CHECK_QUEUE_closure
 
-#define dirtyTSO(tso) \
-    StgTSO_flags(tso) = StgTSO_flags(tso) | TSO_DIRTY::I32;
-
 #define recordMutableCap(p, gen, regs)					\
   W_ __bd;								\
   W_ mut_list;								\
@@ -534,9 +562,13 @@
   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)                                  \
+      P_ __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 */