/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 1996-2010. All Rights Reserved.
*
* The contents of this file are subject to the Erlang Public License,
* Version 1.1, (the "License"); you may not use this file except in
* compliance with the License. You should have received a copy of the
* Erlang Public License along with this software. If not, it can be
* retrieved online at http://www.erlang.org/.
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* %CopyrightEnd%
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "sys.h"
#include "erl_vm.h"
#include "global.h"
#include "export.h"
#include "hash.h"
#define EXPORT_INITIAL_SIZE 4000
#define EXPORT_LIMIT (512*1024)
#define EXPORT_HASH(m,f,a) ((m)*(f)+(a))
static IndexTable export_table; /* Not locked. */
static Hash secondary_export_table; /* Locked. */
#include "erl_smp.h"
static erts_smp_rwmtx_t export_table_lock; /* Locks the secondary export table. */
#define export_read_lock() erts_smp_rwmtx_rlock(&export_table_lock)
#define export_read_unlock() erts_smp_rwmtx_runlock(&export_table_lock)
#define export_write_lock() erts_smp_rwmtx_rwlock(&export_table_lock)
#define export_write_unlock() erts_smp_rwmtx_rwunlock(&export_table_lock)
extern BeamInstr* em_call_error_handler;
extern BeamInstr* em_call_traced_function;
void
export_info(int to, void *to_arg)
{
#ifdef ERTS_SMP
int lock = !ERTS_IS_CRASH_DUMPING;
if (lock)
export_read_lock();
#endif
index_info(to, to_arg, &export_table);
hash_info(to, to_arg, &secondary_export_table);
#ifdef ERTS_SMP
if (lock)
export_read_unlock();
#endif
}
static HashValue
export_hash(Export* x)
{
return EXPORT_HASH(x->code[0], x->code[1], x->code[2]);
}
static int
export_cmp(Export* tmpl, Export* obj)
{
return !(tmpl->code[0] == obj->code[0] &&
tmpl->code[1] == obj->code[1] &&
tmpl->code[2] == obj->code[2]);
}
static Export*
export_alloc(Export* tmpl)
{
Export* obj = (Export*) erts_alloc(ERTS_ALC_T_EXPORT, sizeof(Export));
obj->fake_op_func_info_for_hipe[0] = 0;
obj->fake_op_func_info_for_hipe[1] = 0;
obj->code[0] = tmpl->code[0];
obj->code[1] = tmpl->code[1];
obj->code[2] = tmpl->code[2];
obj->slot.index = -1;
obj->address = obj->code+3;
obj->code[3] = (BeamInstr) em_call_error_handler;
obj->code[4] = 0;
obj->match_prog_set = NULL;
return obj;
}
static void
export_free(Export* obj)
{
erts_free(ERTS_ALC_T_EXPORT, (void*) obj);
}
void
init_export_table(void)
{
HashFunctions f;
erts_smp_rwmtx_opt_t rwmtx_opt = ERTS_SMP_THR_OPTS_DEFAULT_INITER;
rwmtx_opt.type = ERTS_SMP_RWMTX_TYPE_FREQUENT_READ;
rwmtx_opt.lived = ERTS_SMP_RWMTX_LONG_LIVED;
erts_smp_rwmtx_init_opt(&export_table_lock, &rwmtx_opt, "export_tab");
f.hash = (H_FUN) export_hash;
f.cmp = (HCMP_FUN) export_cmp;
f.alloc = (HALLOC_FUN) export_alloc;
f.free = (HFREE_FUN) export_free;
erts_index_init(ERTS_ALC_T_EXPORT_TABLE, &export_table, "export_list",
EXPORT_INITIAL_SIZE, EXPORT_LIMIT, f);
hash_init(ERTS_ALC_T_EXPORT_TABLE, &secondary_export_table,
"secondary_export_table", 50, f);
}
/*
* Return a pointer to the export entry for the given function,
* or NULL otherwise. Notes:
*
* 1) BIFs have export entries and can be called through
* a wrapper in the export entry.
* 2) Functions referenced by a loaded module, but not yet loaded
* also have export entries. The export entry contains
* a wrapper which invokes the error handler if a function is
* called through such an export entry.
* 3) This function is suitable for the implementation of erlang:apply/3.
*/
Export*
erts_find_export_entry(Eterm m, Eterm f, unsigned int a)
{
HashValue hval = EXPORT_HASH((BeamInstr) m, (BeamInstr) f, (BeamInstr) a);
int ix;
HashBucket* b;
ix = hval % export_table.htable.size;
b = export_table.htable.bucket[ix];
/*
* Note: We have inlined the code from hash.c for speed.
*/
while (b != (HashBucket*) 0) {
Export* ep = (Export *) b;
if (ep->code[0] == m && ep->code[1] == f && ep->code[2] == a) {
break;
}
b = b->next;
}
return (Export*)b;
}
/*
* Find the export entry for a loaded function.
* Returns a NULL pointer if the given function is not loaded, or
* a pointer to the export entry.
*
* Note: This function never returns export entries for BIFs
* or functions which are not yet loaded. This makes it suitable
* for use by the erlang:function_exported/3 BIF or whenever you
* cannot depend on the error_handler.
*/
Export*
erts_find_function(Eterm m, Eterm f, unsigned int a)
{
Export e;
Export* ep;
e.code[0] = m;
e.code[1] = f;
e.code[2] = a;
ep = hash_get(&export_table.htable, (void*) &e);
if (ep != NULL && ep->address == ep->code+3 &&
ep->code[3] != (BeamInstr) em_call_traced_function) {
ep = NULL;
}
return ep;
}
/*
* Returns a pointer to an existing export entry for a MFA,
* or creates a new one and returns the pointer.
*
* This function provides unlocked write access to the main export
* table. It should only be used during start up or when
* all other threads are blocked.
*/
Export*
erts_export_put(Eterm mod, Eterm func, unsigned int arity)
{
Export e;
int ix;
ERTS_SMP_LC_ASSERT(erts_initialized == 0 || erts_smp_is_system_blocked(0));
ASSERT(is_atom(mod));
ASSERT(is_atom(func));
e.code[0] = mod;
e.code[1] = func;
e.code[2] = arity;
ix = index_put(&export_table, (void*) &e);
return (Export*) erts_index_lookup(&export_table, ix);
}
/*
* Find the existing export entry for M:F/A. Failing that, create a stub
* export entry (making a call through it will cause the error_handler to
* be called).
*
* Stub export entries will be placed in the secondary export table.
* erts_export_consolidate() will move all stub export entries into the
* main export table (will be done the next time code is loaded).
*/
Export*
erts_export_get_or_make_stub(Eterm mod, Eterm func, unsigned int arity)
{
Export e;
Export* ep;
ASSERT(is_atom(mod));
ASSERT(is_atom(func));
e.code[0] = mod;
e.code[1] = func;
e.code[2] = arity;
ep = erts_find_export_entry(mod, func, arity);
if (ep == 0) {
/*
* The code is not loaded (yet). Put the export in the secondary
* export table, to avoid having to lock the main export table.
*/
export_write_lock();
ep = (Export *) hash_put(&secondary_export_table, (void*) &e);
export_write_unlock();
}
return ep;
}
/*
* To be called before loading code (with other threads blocked).
* This function will move all export entries from the secondary
* export table into the primary.
*/
void
erts_export_consolidate(void)
{
#ifdef DEBUG
HashInfo hi;
#endif
ERTS_SMP_LC_ASSERT(erts_initialized == 0 || erts_smp_is_system_blocked(0));
export_write_lock();
erts_index_merge(&secondary_export_table, &export_table);
erts_hash_merge(&secondary_export_table, &export_table.htable);
export_write_unlock();
#ifdef DEBUG
hash_get_info(&hi, &export_table.htable);
ASSERT(export_table.entries == hi.objs);
#endif
}
Export *export_list(int i)
{
return (Export*) erts_index_lookup(&export_table, i);
}
int export_list_size(void)
{
return export_table.entries;
}
int export_table_sz(void)
{
return index_table_sz(&export_table);
}
Export *export_get(Export *e)
{
return hash_get(&export_table.htable, e);
}
