/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 1996-2013. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions 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))
#ifdef DEBUG
# define IF_DEBUG(x) x
#else
# define IF_DEBUG(x)
#endif
static IndexTable export_tables[ERTS_NUM_CODE_IX]; /* Active not locked */
static erts_smp_atomic_t total_entries_bytes;
#include "erl_smp.h"
/* This lock protects the staging export table from concurrent access
* AND it protects the staging table from becoming active.
*/
erts_smp_mtx_t export_staging_lock;
extern BeamInstr* em_call_error_handler;
extern BeamInstr* em_call_traced_function;
struct export_entry
{
IndexSlot slot; /* MUST BE LOCATED AT TOP OF STRUCT!!! */
Export* ep;
};
/* Helper struct that brings things together in one allocation
*/
struct export_blob
{
Export exp;
struct export_entry entryv[ERTS_NUM_CODE_IX];
/* Note that entryv is not indexed by "code_ix".
*/
};
/* Helper struct only used as template
*/
struct export_templ
{
struct export_entry entry;
Export exp;
};
static struct export_blob* entry_to_blob(struct export_entry* ee)
{
return (struct export_blob*)
((char*)ee->ep - offsetof(struct export_blob,exp));
}
void
export_info(int to, void *to_arg)
{
#ifdef ERTS_SMP
int lock = !ERTS_IS_CRASH_DUMPING;
if (lock)
export_staging_lock();
#endif
index_info(to, to_arg, &export_tables[erts_active_code_ix()]);
hash_info(to, to_arg, &export_tables[erts_staging_code_ix()].htable);
#ifdef ERTS_SMP
if (lock)
export_staging_unlock();
#endif
}
static HashValue
export_hash(struct export_entry* ee)
{
Export* x = ee->ep;
return EXPORT_HASH(x->code[0], x->code[1], x->code[2]);
}
static int
export_cmp(struct export_entry* tmpl_e, struct export_entry* obj_e)
{
Export* tmpl = tmpl_e->ep;
Export* obj = obj_e->ep;
return !(tmpl->code[0] == obj->code[0] &&
tmpl->code[1] == obj->code[1] &&
tmpl->code[2] == obj->code[2]);
}
static struct export_entry*
export_alloc(struct export_entry* tmpl_e)
{
struct export_blob* blob;
unsigned ix;
if (tmpl_e->slot.index == -1) { /* Template, allocate blob */
Export* tmpl = tmpl_e->ep;
Export* obj;
blob = (struct export_blob*) erts_alloc(ERTS_ALC_T_EXPORT, sizeof(*blob));
erts_smp_atomic_add_nob(&total_entries_bytes, sizeof(*blob));
obj = &blob->exp;
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->code[3] = (BeamInstr) em_call_error_handler;
obj->code[4] = 0;
for (ix=0; ix<ERTS_NUM_CODE_IX; ix++) {
obj->addressv[ix] = obj->code+3;
blob->entryv[ix].slot.index = -1;
blob->entryv[ix].ep = &blob->exp;
}
ix = 0;
}
else { /* Existing entry in another table, use free entry in blob */
blob = entry_to_blob(tmpl_e);
for (ix = 0; blob->entryv[ix].slot.index >= 0; ix++) {
ASSERT(ix < ERTS_NUM_CODE_IX);
}
}
return &blob->entryv[ix];
}
static void
export_free(struct export_entry* obj)
{
struct export_blob* blob = entry_to_blob(obj);
int i;
obj->slot.index = -1;
for (i=0; i < ERTS_NUM_CODE_IX; i++) {
if (blob->entryv[i].slot.index >= 0) {
return;
}
}
erts_free(ERTS_ALC_T_EXPORT, blob);
erts_smp_atomic_add_nob(&total_entries_bytes, -sizeof(*blob));
}
void
init_export_table(void)
{
HashFunctions f;
int i;
erts_smp_mtx_init(&export_staging_lock, "export_tab");
erts_smp_atomic_init_nob(&total_entries_bytes, 0);
f.hash = (H_FUN) export_hash;
f.cmp = (HCMP_FUN) export_cmp;
f.alloc = (HALLOC_FUN) export_alloc;
f.free = (HFREE_FUN) export_free;
for (i=0; i<ERTS_NUM_CODE_IX; i++) {
erts_index_init(ERTS_ALC_T_EXPORT_TABLE, &export_tables[i], "export_list",
EXPORT_INITIAL_SIZE, EXPORT_LIMIT, 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.
*/
extern Export* /* inline-helper */
erts_find_export_entry(Eterm m, Eterm f, unsigned int a,ErtsCodeIndex code_ix);
Export*
erts_find_export_entry(Eterm m, Eterm f, unsigned int a, ErtsCodeIndex code_ix)
{
HashValue hval = EXPORT_HASH((BeamInstr) m, (BeamInstr) f, (BeamInstr) a);
int ix;
HashBucket* b;
ix = hval % export_tables[code_ix].htable.size;
b = export_tables[code_ix].htable.bucket[ix];
/*
* Note: We have inlined the code from hash.c for speed.
*/
while (b != (HashBucket*) 0) {
Export* ep = ((struct export_entry*) b)->ep;
if (ep->code[0] == m && ep->code[1] == f && ep->code[2] == a) {
return ep;
}
b = b->next;
}
return NULL;
}
static struct export_entry* init_template(struct export_templ* templ,
Eterm m, Eterm f, unsigned a)
{
templ->entry.ep = &templ->exp;
templ->entry.slot.index = -1;
templ->exp.code[0] = m;
templ->exp.code[1] = f;
templ->exp.code[2] = a;
return &templ->entry;
}
/*
* 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, ErtsCodeIndex code_ix)
{
struct export_templ templ;
struct export_entry* ee;
ee = hash_get(&export_tables[code_ix].htable, init_template(&templ, m, f, a));
if (ee == NULL ||
(ee->ep->addressv[code_ix] == ee->ep->code+3 &&
ee->ep->code[3] != (BeamInstr) BeamOp(op_i_generic_breakpoint))) {
return NULL;
}
return ee->ep;
}
/*
* Returns a pointer to an existing export entry for a MFA,
* or creates a new one and returns the pointer.
*
* This function acts on the staging export table. It should only be used
* to load new code.
*/
Export*
erts_export_put(Eterm mod, Eterm func, unsigned int arity)
{
ErtsCodeIndex code_ix = erts_staging_code_ix();
struct export_templ templ;
struct export_entry* ee;
ASSERT(is_atom(mod));
ASSERT(is_atom(func));
export_staging_lock();
ee = (struct export_entry*) index_put_entry(&export_tables[code_ix],
init_template(&templ, mod, func, arity));
export_staging_unlock();
return ee->ep;
}
/*
* 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 loader export table.
*/
Export*
erts_export_get_or_make_stub(Eterm mod, Eterm func, unsigned int arity)
{
ErtsCodeIndex code_ix;
Export* ep;
IF_DEBUG(int retrying = 0;)
ASSERT(is_atom(mod));
ASSERT(is_atom(func));
do {
code_ix = erts_active_code_ix();
ep = erts_find_export_entry(mod, func, arity, code_ix);
if (ep == 0) {
/*
* The code is not loaded (yet). Put the export in the staging
* export table, to avoid having to lock the active export table.
*/
export_staging_lock();
if (erts_active_code_ix() == code_ix) {
struct export_templ templ;
struct export_entry* entry;
IndexTable* tab = &export_tables[erts_staging_code_ix()];
init_template(&templ, mod, func, arity);
entry = (struct export_entry *) index_put_entry(tab, &templ.entry);
ep = entry->ep;
ASSERT(ep);
}
else { /* race */
ASSERT(!retrying);
IF_DEBUG(retrying = 1);
}
export_staging_unlock();
}
} while (!ep);
return ep;
}
Export *export_list(int i, ErtsCodeIndex code_ix)
{
return ((struct export_entry*) erts_index_lookup(&export_tables[code_ix], i))->ep;
}
int export_list_size(ErtsCodeIndex code_ix)
{
return export_tables[code_ix].entries;
}
int export_table_sz(void)
{
int i, bytes = 0;
export_staging_lock();
for (i=0; i<ERTS_NUM_CODE_IX; i++) {
bytes += index_table_sz(&export_tables[i]);
}
export_staging_unlock();
return bytes;
}
int export_entries_sz(void)
{
return erts_smp_atomic_read_nob(&total_entries_bytes);
}
Export *export_get(Export *e)
{
struct export_entry ee;
struct export_entry* entry;
ee.ep = e;
entry = (struct export_entry*)hash_get(&export_tables[erts_active_code_ix()].htable, &ee);
return entry ? entry->ep : NULL;
}
IF_DEBUG(static ErtsCodeIndex debug_start_load_ix = 0;)
void export_start_staging(void)
{
ErtsCodeIndex dst_ix = erts_staging_code_ix();
ErtsCodeIndex src_ix = erts_active_code_ix();
IndexTable* dst = &export_tables[dst_ix];
IndexTable* src = &export_tables[src_ix];
struct export_entry* src_entry;
#ifdef DEBUG
struct export_entry* dst_entry;
#endif
int i;
ASSERT(dst_ix != src_ix);
ASSERT(debug_start_load_ix == -1);
export_staging_lock();
/*
* Insert all entries in src into dst table
*/
for (i = 0; i < src->entries; i++) {
src_entry = (struct export_entry*) erts_index_lookup(src, i);
src_entry->ep->addressv[dst_ix] = src_entry->ep->addressv[src_ix];
#ifdef DEBUG
dst_entry = (struct export_entry*)
#endif
index_put_entry(dst, src_entry);
ASSERT(entry_to_blob(src_entry) == entry_to_blob(dst_entry));
}
export_staging_unlock();
IF_DEBUG(debug_start_load_ix = dst_ix);
}
void export_end_staging(int commit)
{
ASSERT(debug_start_load_ix == erts_staging_code_ix());
IF_DEBUG(debug_start_load_ix = -1);
}
