/* * %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); }