6 files changed, 249 insertions, 36 deletions

diff --git a/erts/emulator/beam/beam_bif_load.c b/erts/emulator/beam/beam_bif_load.c
index 90baa6178e..a8ef198be5 100644
--- a/erts/emulator/beam/beam_bif_load.c
+++ b/erts/emulator/beam/beam_bif_load.c
@@ -86,11 +86,15 @@ load_module_2(BIF_ALIST_2)
     erts_smp_proc_unlock(BIF_P, ERTS_PROC_LOCK_MAIN);
     erts_smp_thr_progress_block();
 
+    erts_start_loader_code_ix();
+
     reason = erts_finish_loading(stp, BIF_P, 0, &BIF_ARG_1);
     if (reason != NIL) {
+	erts_abort_loader_code_ix();
 	res = TUPLE2(hp, am_error, reason);
     } else {
 	set_default_trace_pattern(BIF_ARG_1);
+	erts_commit_loader_code_ix();
 	res = TUPLE2(hp, am_module, BIF_ARG_1);
     }
 
@@ -374,7 +378,8 @@ BIF_RETTYPE finish_after_on_load_2(BIF_ALIST_2)
 	code = modp->curr.code;
 	end = (BeamInstr *)((char *)code + modp->curr.code_length);
 	erts_cleanup_funs_on_purge(code, end);
-	beam_catches_delmod(modp->curr.catches, code, modp->curr.code_length);
+	beam_catches_delmod(modp->curr.catches, code, modp->curr.code_length,
+			    erts_active_code_ix());
 	erts_free(ERTS_ALC_T_CODE, (void *) code);
 	modp->curr.code = NULL;
 	modp->curr.code_length = 0;
@@ -667,7 +672,8 @@ purge_module(int module)
     code = modp->old.code;
     end = (BeamInstr *)((char *)code + modp->old.code_length);
     erts_cleanup_funs_on_purge(code, end);
-    beam_catches_delmod(modp->old.catches, code, modp->old.code_length);
+    beam_catches_delmod(modp->old.catches, code, modp->old.code_length,
+			erts_active_code_ix());
     decrement_refc(code);
     erts_free(ERTS_ALC_T_CODE, (void *) code);
     modp->old.code = NULL;
diff --git a/erts/emulator/beam/beam_catches.c b/erts/emulator/beam/beam_catches.c
index 406ef1db5f..72bd3583e1 100644
--- a/erts/emulator/beam/beam_catches.c
+++ b/erts/emulator/beam/beam_catches.c
@@ -31,24 +31,77 @@ typedef struct {
     unsigned cdr;
 } beam_catch_t;
 
-static int free_list;
-static unsigned high_mark;
-static unsigned tabsize;
-static beam_catch_t *beam_catches;
+#ifdef DEBUG
+#  define IF_DEBUG(x) x
+#else
+#  define IF_DEBUG(x)
+#endif
+
+struct bc_code_ix { /*SVERK A better name maybe... */
+    int free_list;
+    unsigned high_mark;
+    unsigned tabsize;
+    beam_catch_t *beam_catches;
+
+    IF_DEBUG(int is_prepared;)
+};
+
+static struct bc_code_ix bccix[ERTS_NUM_CODE_IX];
 
 void beam_catches_init(void)
 {
-    tabsize   = DEFAULT_TABSIZE;
-    free_list = -1;
-    high_mark = 0;
+    int i;
+
+    bccix[0].tabsize   = DEFAULT_TABSIZE;
+    bccix[0].free_list = -1;
+    bccix[0].high_mark = 0;
+    bccix[0].beam_catches = erts_alloc(ERTS_ALC_T_CODE,
+				     sizeof(beam_catch_t)*DEFAULT_TABSIZE);
+    IF_DEBUG(bccix[0].is_prepared = 0);
+    for (i=1; i<ERTS_NUM_CODE_IX; i++) {
+	bccix[i] = bccix[i-1];
+    }
+     /* For initial load: */
+    IF_DEBUG(bccix[erts_loader_code_ix()].is_prepared = 1);
+}
+
+
+static void gc_old_vec(beam_catch_t* vec)
+{
+    int i;
+    for (i=0; i<ERTS_NUM_CODE_IX; i++) {
+	if (bccix[i].beam_catches == vec) {
+	    return;
+	}
+    }
+    erts_free(ERTS_ALC_T_CODE, vec);
+}
+
+
+void beam_catches_start_load(void)
+{
+    ErtsCodeIndex dst = erts_loader_code_ix();
+    ErtsCodeIndex src = erts_active_code_ix();
+    beam_catch_t* prev_vec = bccix[dst].beam_catches;
+
+    ASSERT(!bccix[src].is_prepared && !bccix[dst].is_prepared);
 
-    beam_catches = erts_alloc(ERTS_ALC_T_CODE, sizeof(beam_catch_t)*DEFAULT_TABSIZE);
+    bccix[dst] = bccix[src];
+    gc_old_vec(prev_vec);
+    IF_DEBUG(bccix[dst].is_prepared = 1);
+}
+
+void beam_catches_end_load(int commit)
+{
+    IF_DEBUG(bccix[erts_loader_code_ix()].is_prepared = 0);
 }
 
 unsigned beam_catches_cons(BeamInstr *cp, unsigned cdr)
 {
     int i;
+    struct bc_code_ix* p = &bccix[erts_loader_code_ix()];
 
+    ASSERT(p->is_prepared);
     /*
      * Allocate from free_list while it is non-empty.
      * If free_list is empty, allocate at high_mark.
@@ -56,53 +109,64 @@ unsigned beam_catches_cons(BeamInstr *cp, unsigned cdr)
      * This avoids the need to initialise the free list in
      * beam_catches_init(), which would cost O(TABSIZ) time.
      */
-    if( free_list >= 0 ) {
-	i = free_list;
-	free_list = beam_catches[i].cdr;
-    } else if( high_mark < tabsize ) {
-	i = high_mark;
-	high_mark++;
-    } else {
-	/* No free slots and table is full: realloc table */
-	tabsize      = 2*tabsize;
-	beam_catches = erts_realloc(ERTS_ALC_T_CODE, beam_catches, sizeof(beam_catch_t)*tabsize);
-	i = high_mark;
-	high_mark++;
+    if (p->free_list >= 0) {
+	i = p->free_list;
+	p->free_list = p->beam_catches[i].cdr;
+    }
+    else {
+	if (p->high_mark >= p->tabsize) {
+	    /* No free slots and table is full: realloc table */
+	    beam_catch_t* prev_vec = p->beam_catches;
+	    unsigned newsize = p->tabsize*2;
+
+	    p->beam_catches = erts_alloc(ERTS_ALC_T_CODE,
+					 newsize*sizeof(beam_catch_t));
+	    sys_memcpy(p->beam_catches, prev_vec,
+		       p->tabsize*sizeof(beam_catch_t));
+	    gc_old_vec(prev_vec);
+	    p->tabsize = newsize;
+	}
+	i = p->high_mark++;
     }
 
-    beam_catches[i].cp  = cp;
-    beam_catches[i].cdr = cdr;
+    p->beam_catches[i].cp  = cp;
+    p->beam_catches[i].cdr = cdr;
 
     return i;
 }
 
 BeamInstr *beam_catches_car(unsigned i)
 {
-    if( i >= tabsize ) {
+    struct bc_code_ix* p = &bccix[erts_active_code_ix()];
+
+    if (i >= p->tabsize ) {
 	erl_exit(1, "beam_catches_delmod: index %#x is out of range\r\n", i);
     }
-    return beam_catches[i].cp;
+    return p->beam_catches[i].cp;
 }
 
-void beam_catches_delmod(unsigned head, BeamInstr *code, unsigned code_bytes)
+void beam_catches_delmod(unsigned head, BeamInstr *code, unsigned code_bytes,
+			 ErtsCodeIndex code_ix)
 {
+    struct bc_code_ix* p = &bccix[code_ix];
     unsigned i, cdr;
 
+    ASSERT((code_ix == erts_active_code_ix()) != bccix[erts_loader_code_ix()].is_prepared);
     for(i = head; i != (unsigned)-1;) {
-	if( i >= tabsize ) {
+	if (i >= p->tabsize) {
 	    erl_exit(1, "beam_catches_delmod: index %#x is out of range\r\n", i);
 	}
-	if( (char*)beam_catches[i].cp - (char*)code >= code_bytes ) {
+	if( (char*)p->beam_catches[i].cp - (char*)code >= code_bytes ) {
 	    erl_exit(1,
 		    "beam_catches_delmod: item %#x has cp %#lx which is not "
 		    "in module's range [%#lx,%#lx[\r\n",
-		    i, (long)beam_catches[i].cp,
+		    i, (long)p->beam_catches[i].cp,
 		    (long)code, (long)((char*)code + code_bytes));
 	}
-	beam_catches[i].cp = 0;
-	cdr = beam_catches[i].cdr;
-	beam_catches[i].cdr = free_list;
-	free_list = i;
+	p->beam_catches[i].cp = 0;
+	cdr = p->beam_catches[i].cdr;
+	p->beam_catches[i].cdr = p->free_list;
+	p->free_list = i;
 	i = cdr;
     }
 }
diff --git a/erts/emulator/beam/beam_catches.h b/erts/emulator/beam/beam_catches.h
index 6223427f0d..970772806b 100644
--- a/erts/emulator/beam/beam_catches.h
+++ b/erts/emulator/beam/beam_catches.h
@@ -20,12 +20,17 @@
 #ifndef __BEAM_CATCHES_H
 #define __BEAM_CATCHES_H
 
+#include "global.h"  /*SVERK the code_ix stuff */
+
 #define BEAM_CATCHES_NIL	(-1)
 
 void beam_catches_init(void);
+void beam_catches_start_load(void);
+void beam_catches_end_load(int commit);
 unsigned beam_catches_cons(BeamInstr* cp, unsigned cdr);
 BeamInstr *beam_catches_car(unsigned i);
-void beam_catches_delmod(unsigned head, BeamInstr* code, unsigned code_bytes);
+void beam_catches_delmod(unsigned head, BeamInstr* code, unsigned code_bytes,
+			 ErtsCodeIndex);
 
 #define catch_pc(x)	beam_catches_car(catch_val((x)))
 
diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c
index 27a5e72113..f7c8395cb6 100644
--- a/erts/emulator/beam/beam_load.c
+++ b/erts/emulator/beam/beam_load.c
@@ -6101,3 +6101,95 @@ static int safe_mul(UWord a, UWord b, UWord* resp)
 	return (res / b) == a;
     }
 }
+
+
+/*SVERK Do these deserve a file of their own maybe? */
+
+static erts_smp_atomic32_t the_active_code_index;
+static erts_smp_atomic32_t the_loader_code_index;
+
+#ifdef DEBUG
+# define CIX_TRACE(text) erts_fprintf(stderr, "CIX_TRACE: " text " act=%u load=%u\r\n", erts_active_code_ix(), erts_loader_code_ix())
+#else
+# define CIX_TRACE(text)
+#endif
+
+void erts_code_ix_init(void)
+{
+    erts_smp_atomic32_init_nob(&the_active_code_index, 0);
+    erts_smp_atomic32_init_nob(&the_loader_code_index, 0);
+    CIX_TRACE("init");
+}
+ErtsCodeIndex erts_active_code_ix(void)
+{
+    return erts_smp_atomic32_read_nob(&the_active_code_index);
+}
+ErtsCodeIndex erts_loader_code_ix(void)
+{
+    return erts_smp_atomic32_read_nob(&the_loader_code_index);
+}
+
+/* Lock code_ix (enqueue and suspend until we get it)
+*/
+void erts_lock_code_ix(void)
+{
+}
+
+/* Unlock code_ix (resume first waiter)
+*/
+void erts_unlock_code_ix(void)
+{
+}
+
+void erts_start_loader_code_ix(void)
+{
+    beam_catches_start_load();
+    /*SVERK and more to come I guess...
+	:
+     */
+    CIX_TRACE("start");
+}
+
+
+void erts_commit_loader_code_ix(void)
+{
+    beam_catches_end_load(1);
+    {
+	ErtsCodeIndex ix = erts_loader_code_ix();
+	erts_smp_atomic32_set_nob(&the_active_code_index, ix);
+	ix = (ix + 1) % ERTS_NUM_CODE_IX;
+	erts_smp_atomic32_set_nob(&the_loader_code_index, ix);
+    }
+    CIX_TRACE("commit");
+}
+
+void erts_abort_loader_code_ix(void)
+{
+    beam_catches_end_load(0);
+    CIX_TRACE("abort");
+}
+
+/*SVERK old_code lock should maybe be part of module.c */
+void erts_rwlock_old_code(void)
+{
+}
+void erts_rwunlock_old_code(void)
+{
+}
+void erts_rlock_old_code(void)
+{
+}
+void erts_runlock_old_code(void)
+{
+}
+
+#ifdef ERTS_ENABLE_LOCK_CHECK
+int erts_is_old_code_rlocked(void)
+{
+    return 1;
+}
+int erts_is_code_ix_locked(void)
+{
+    return 1;
+}
+#endif
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 717315d8bd..8d382057dc 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -236,7 +236,7 @@ void erl_error(char *fmt, va_list args)
 static int early_init(int *argc, char **argv);
 
 void
-erts_short_init(void)
+erts_short_init_SVERK_SAYS_NOT_USED(void)
 {
     int ncpu = early_init(NULL, NULL);
     erl_init(ncpu);
@@ -264,6 +264,7 @@ erl_init(int ncpu)
     erts_init_trace();
     erts_init_binary();
     erts_init_bits();
+    erts_code_ix_init();
     erts_init_fun_table();
     init_atom_table();
     init_export_table();
@@ -1471,6 +1472,7 @@ erl_start(int argc, char **argv)
 
     init_shared_memory(boot_argc, boot_argv);
     load_preloaded();
+    erts_commit_loader_code_ix();
 
     erts_initialized = 1;
 
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 46bc58891b..8745ca610b 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -28,6 +28,50 @@
 #include "hash.h"
 #include "index.h"
 #include "atom.h"
+
+/*SVERK maybe put this is some other header, must be before module.h and export.h */
+#define ERTS_NUM_CODE_IX 3
+typedef unsigned ErtsCodeIndex;
+
+void erts_code_ix_init(void);
+ErtsCodeIndex erts_active_code_ix(void);
+ErtsCodeIndex erts_loader_code_ix(void);
+
+/* Lock code_ix (enqueue and suspend until we get it)
+*/
+void erts_lock_code_ix(void);
+
+/*SVERK
+    erts_lock_code_ix();
+    wait for thread progress
+	   (we don't want any retarded threads with pointers to inactive Module)
+    Copy active -> loader
+	rlock old_code while copying Modules
+    Update loader
+    wait for thread progress
+	   (we need a membarrier for everybody to "see" the new code)
+    Set loader as new active
+    erts_unlock_code_ix();
+}*/
+
+
+/* Unlock code_ix (resume first waiter)
+*/
+void erts_unlock_code_ix(void);
+void erts_start_loader_code_ix(void);
+void erts_commit_loader_code_ix(void);
+void erts_abort_loader_code_ix(void);
+
+void erts_rwlock_old_code(void);
+void erts_rwunlock_old_code(void);
+void erts_rlock_old_code(void);
+void erts_runlock_old_code(void);
+
+#ifdef ERTS_ENABLE_LOCK_CHECK
+int erts_is_old_code_rlocked(void);
+int erts_is_code_ix_locked(void);
+#endif
+
 #include "export.h"
 #include "module.h"
 #include "register.h"