Mending halfword heap emulator

erts/emulator/beam/beam_bp.h

@@ -123,7 +123,7 @@ typedef struct {
     Uint ms;
     Uint s;
     Uint us;
-    Uint *pc;
+    BeamInstr *pc;
 } process_breakpoint_time_t; /* used within psd */
 
 extern erts_smp_spinlock_t erts_bp_lock;

erts/emulator/beam/beam_emu.c

@@ -4463,7 +4463,7 @@ void process_main(void)
 	     E -= 2;
 	     E[0] = make_cp(I);
 	     E[1] = make_cp(c_p->cp);     /* original return address */
-	     c_p->cp = (BeamInstr *) make_cp(beam_return_time_trace);
+	     c_p->cp = beam_return_time_trace;
 	 }
      }
 
@@ -4493,20 +4493,20 @@ void process_main(void)
      BeamInstr real_I;
      Uint32 flags;
      Eterm tracer_pid;
-     BeamInstr *cpp;
+     Uint* cpp;
      int return_to_trace = 0, need = 0;
      flags = 0;
      SWAPOUT;
      reg[0] = r(0);
 
      if (*(c_p->cp) == (BeamInstr) OpCode(return_trace)) {
-	 cpp = (BeamInstr*)&E[2];
+	 cpp = &E[2];
      } else if (*(c_p->cp) == (BeamInstr) OpCode(i_return_to_trace)) {
 	 return_to_trace = !0;
-	 cpp = (BeamInstr*)&E[0];
+	 cpp = &E[0];
      } else if (*(c_p->cp) == (BeamInstr) OpCode(i_return_time_trace)) {
 	 return_to_trace = !0;
-	 cpp = (BeamInstr*)&E[0];
+	 cpp = &E[0];
      } else {
 	 cpp = NULL;
      }

erts/emulator/beam/erl_gc.c

@@ -146,6 +146,9 @@ erts_init_gc(void)
     ASSERT(offsetof(ProcBin,thing_word) == offsetof(struct erl_off_heap_header,thing_word));
     ASSERT(offsetof(ProcBin,thing_word) == offsetof(ErlFunThing,thing_word));
     ASSERT(offsetof(ProcBin,thing_word) == offsetof(ExternalThing,header));
+    ASSERT(offsetof(ProcBin,size) == offsetof(struct erl_off_heap_header,size));
+    ASSERT(offsetof(ProcBin,size) == offsetof(ErlSubBin,size));
+    ASSERT(offsetof(ProcBin,size) == offsetof(ErlHeapBin,size));
     ASSERT(offsetof(ProcBin,next) == offsetof(struct erl_off_heap_header,next));
     ASSERT(offsetof(ProcBin,next) == offsetof(ErlFunThing,next));
     ASSERT(offsetof(ProcBin,next) == offsetof(ExternalThing,next));
@@ -2111,9 +2114,9 @@ sweep_off_heap(Process *p, int fullsweep)
 		int to_new_heap = !in_area(ptr, oheap, oheap_sz);
 		ASSERT(to_new_heap == !seen_mature || (!to_new_heap && (seen_mature=1)));
 		if (to_new_heap) {
-		    bin_vheap += ptr->u.size / sizeof(Eterm);
+		    bin_vheap += ptr->size / sizeof(Eterm);
 		} else {
-		    BIN_OLD_VHEAP(p) += ptr->u.size / sizeof(Eterm); /* for binary gc (words)*/
+		    BIN_OLD_VHEAP(p) += ptr->size / sizeof(Eterm); /* for binary gc (words)*/
 		}		
 		link_live_proc_bin(&shrink, &prev, &ptr, to_new_heap);
 	    }
@@ -2157,7 +2160,7 @@ sweep_off_heap(Process *p, int fullsweep)
 	ASSERT(in_area(ptr, oheap, oheap_sz));
 	ASSERT(!IS_MOVED_BOXED(ptr->thing_word));       
 	if (ptr->thing_word == HEADER_PROC_BIN) {
-	    BIN_OLD_VHEAP(p) += ptr->u.size / sizeof(Eterm); /* for binary gc (words)*/
+	    BIN_OLD_VHEAP(p) += ptr->size / sizeof(Eterm); /* for binary gc (words)*/
 	    link_live_proc_bin(&shrink, &prev, &ptr, 0);
 	}
 	else {

erts/emulator/beam/erl_message.h

@@ -30,10 +30,10 @@ struct external_thing_;
 
 struct erl_off_heap_header {
     Eterm thing_word;
-    union {
-	Uint size;
-	void* ptr;
-    }u;
+    Uint size;
+#if HALFWORD_HEAP
+    void* dummy_ptr_padding__;
+#endif
     struct erl_off_heap_header* next;
 };
 

erts/emulator/beam/erl_term.h

@@ -821,10 +821,10 @@ _ET_DECLARE_CHECKED(struct erl_node_*,internal_ref_node,Eterm)
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  *  |A A A A A A A A A A A A A A A A A A A A A A A A A A|t t t t|0 0| Thing
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
- *  |N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N| Next
- *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  *  |E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E| ErlNode
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N| Next
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  *  |X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X| Data 0
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  *  .                                                               .   .
@@ -835,7 +835,7 @@ _ET_DECLARE_CHECKED(struct erl_node_*,internal_ref_node,Eterm)
  *  t : External pid thing tag  (1100)
  *  t : External port thing tag (1101)
  *  t : External ref thing tag  (1110)
- *  N : Next (external thing) pointer
+ *  N : Next (off_heap) pointer
  *  E : ErlNode pointer
  *  X : Type specific data
  *
@@ -852,8 +852,11 @@ _ET_DECLARE_CHECKED(struct erl_node_*,internal_ref_node,Eterm)
 /* XXX:PaN - this structure is not perfect for halfword heap, it takes
    a lot of memory due to padding, and the array will not begin at the end of the
    structure, as otherwise expected. Be sure to access data.ui32 array and not try
-   to do pointer manipulation on an Eterm * to reach the actual data... */
+   to do pointer manipulation on an Eterm * to reach the actual data...
 
+   XXX:Sverk - Problem made worse by "one off-heap list" when 'next' pointer
+     must align with 'next' in ProcBin, erl_fun_thing and erl_off_heap_header.
+*/
 typedef struct external_thing_ {
     /*                                 ----+                        */
     Eterm                   header;     /* |                        */

erts/emulator/beam/global.h

@@ -465,7 +465,7 @@ typedef struct proc_bin {
     Eterm thing_word;		/* Subtag REFC_BINARY_SUBTAG. */
     Uint size;			/* Binary size in bytes. */
 #if HALFWORD_HEAP
-    char alignment__[SIZEOF_VOID_P - ERTS_SIZEOF_ETERM];
+    void* dummy_ptr_padding__;
 #endif
     struct erl_off_heap_header *next;
     Binary *val;		/* Pointer to Binary structure. */