C++ BeamOp函數代碼示例

int
erts_is_native_break(BeamInstr *pc) {
#ifdef HIPE
    ASSERT(pc[-5] == (BeamInstr) BeamOp(op_i_func_info_IaaI));
    return pc[0]  == (BeamInstr) BeamOp(op_hipe_trap_call)
	|| pc[0]  == (BeamInstr) BeamOp(op_hipe_trap_call_closure);
#else
    return 0;
#endif
}

void
erts_install_breakpoints(BpFunctions* f)
{
    Uint i;
    Uint n = f->matched;
    BeamInstr br = (BeamInstr) BeamOp(op_i_generic_breakpoint);

    for (i = 0; i < n; i++) {
	BeamInstr* pc = f->matching[i].pc;
	GenericBp* g = (GenericBp *) pc[-4];
	if (*pc != br && g) {
	    Module* modp = f->matching[i].mod;

	    /*
	     * The breakpoint must be disabled in the active data
	     * (it will enabled later by switching bp indices),
	     * and enabled in the staging data.
	     */
	    ASSERT(g->data[erts_active_bp_ix()].flags == 0);
	    ASSERT(g->data[erts_staging_bp_ix()].flags != 0);

	    /*
	     * The following write is not protected by any lock. We
	     * assume that the hardware guarantees that a write of an
	     * aligned word-size (or half-word) writes is atomic
	     * (i.e. that other processes executing this code will not
	     * see a half pointer).
	     */
	    *pc = br;
	    modp->curr.num_breakpoints++;
	}
    }
}

	/* Empty loop body */
    }
    for (i = specified; i < 3; i++) {
	if (mfa[i] != am_Underscore) {
	    goto error;
	}
    }
    if (is_small(mfa[2])) {
	mfa[2] = signed_val(mfa[2]);
    }

    if (!erts_try_seize_code_write_permission(BIF_P)) {
	ERTS_BIF_YIELD2(bif_export[BIF_erts_debug_breakpoint_2],
			BIF_P, BIF_ARG_1, BIF_ARG_2);
    }
    erts_smp_proc_unlock(p, ERTS_PROC_LOCK_MAIN);
    erts_smp_thr_progress_block();

    erts_bp_match_functions(&f, mfa, specified);
    if (boolean == am_true) {
	erts_set_debug_break(&f);
	erts_install_breakpoints(&f);
	erts_commit_staged_bp();
    } else {
	erts_clear_debug_break(&f);
	erts_commit_staged_bp();
	erts_uninstall_breakpoints(&f);
    }
    erts_consolidate_bp_data(&f, 1);
    res = make_small(f.matched);
    erts_bp_free_matched_functions(&f);

    erts_smp_thr_progress_unblock();
    erts_smp_proc_lock(p, ERTS_PROC_LOCK_MAIN);
    erts_release_code_write_permission();
    return res;

 error:
    BIF_ERROR(p, BADARG);
}

#if 0 /* Kept for conveninence when hard debugging. */
void debug_dump_code(BeamInstr *I, int num)
{
    BeamInstr *code_ptr = I;
    BeamInstr *end = code_ptr + num;
    erts_dsprintf_buf_t *dsbufp;
    BeamInstr instr;
    int i;

    dsbufp = erts_create_tmp_dsbuf(0);
    while (code_ptr < end) {
	erts_print(ERTS_PRINT_DSBUF, (void *) dsbufp, HEXF ": ", code_ptr);
	instr = (BeamInstr) code_ptr[0];
	for (i = 0; i < NUM_SPECIFIC_OPS; i++) {
	    if (instr == (BeamInstr) BeamOp(i) && opc[i].name[0] != '\0') {
		code_ptr += print_op(ERTS_PRINT_DSBUF, (void *) dsbufp,
				     i, opc[i].sz-1, code_ptr+1) + 1;
		break;
	    }
	}
	if (i >= NUM_SPECIFIC_OPS) {
	    erts_print(ERTS_PRINT_DSBUF, (void *) dsbufp,
		       "unknown " HEXF "\n", instr);
	    code_ptr++;
	}
    }
    dsbufp->str[dsbufp->str_len] = 0;
    erts_fprintf(stderr,"%s", dsbufp->str);
    erts_destroy_tmp_dsbuf(dsbufp);
}

/*
 * SMP NOTE: Process p may have become exiting on return!
 */
BeamInstr
erts_trace_break(Process *p, BeamInstr *pc, Eterm *args,
		 Uint32 *ret_flags, Eterm *tracer_pid) {
    Eterm tpid1, tpid2;
    BpData **bds = (BpData **) (pc)[-4];
    BpDataTrace *bdt = NULL;

    ASSERT(bds);
    ASSERT(pc[-5] == (BeamInstr) BeamOp(op_i_func_info_IaaI));
    bdt = (BpDataTrace *) bds[bp_sched2ix_proc(p)];
    ASSERT(bdt);
    bdt = (BpDataTrace *) bdt->next;
    ASSERT(bdt);
    ASSERT(ret_flags);
    ASSERT(tracer_pid);

    ErtsSmpBPLock(bdt);
    tpid1 = tpid2 = bdt->tracer_pid;
    ErtsSmpBPUnlock(bdt);

    *ret_flags = erts_call_trace(p, pc-3/*mfa*/, bdt->match_spec, args,
				 1, &tpid2);
    *tracer_pid = tpid2;
    if (tpid1 != tpid2) {
	ErtsSmpBPLock(bdt);
	bdt->tracer_pid = tpid2;
	ErtsSmpBPUnlock(bdt);
    }
    bds[bp_sched2ix_proc(p)] = (BpData *) bdt;
    return bdt->orig_instr;
}

static int set_module_break(Module *modp, Eterm mfa[3], int specified,
			    Binary *match_spec, Uint break_op, 
			    enum erts_break_op count_op, Eterm tracer_pid) {
    Uint** code_base;
    Uint* code_ptr;
    int num_processed = 0;
    Uint i,n;

    ASSERT(break_op);
    ASSERT(modp);
    code_base = (Uint **) modp->code;
    if (code_base == NULL) {
	return 0;
    }
    n = (Uint) code_base[MI_NUM_FUNCTIONS];
    for (i = 0; i < n; ++i) {
	code_ptr = code_base[MI_FUNCTIONS+i];
	ASSERT(code_ptr[0] == (Uint) BeamOp(op_i_func_info_IaaI));
	if ((specified < 2 || mfa[1] == ((Eterm) code_ptr[3])) &&
	    (specified < 3 || ((int) mfa[2]) == ((int) code_ptr[4]))) {
	    Uint   *pc = code_ptr+5;
	    
	    num_processed +=
		set_function_break(modp, pc, match_spec, 
				   break_op, count_op, tracer_pid);
	}
    }
    return num_processed;
}

/*
** Searches (linear forward) the breakpoint ring for a specified opcode
** and returns a pointer to the breakpoint data structure or NULL if
** not found. If the specified opcode is 0, the last breakpoint is 
** returned. The program counter must point to the first executable
** (breakpoint) instruction of the function.
*/
static BpData *is_break(Uint *pc, Uint break_op) {
    ASSERT(pc[-5] == (Uint) BeamOp(op_i_func_info_IaaI));
    if (! erts_is_native_break(pc)) {
	BpData *bd = (BpData *) pc[-4];
	
	if (break_op == 0) {
	    return bd;
	}
	if (*pc == break_op) {
	    ASSERT(bd);
	    return bd->next;
	}
	if (! bd){
	    return NULL;
	}
	bd = bd->next;
	while (bd != (BpData *) pc[-4]) {
	    ASSERT(bd);
	    if (bd->orig_instr == break_op) {
		bd = bd->next;
		ASSERT(bd);
		return bd;
	    } else {
		bd = bd->next;
	    }
	}
    }
    return NULL;
}

/*
 * SMP NOTE: Process p may have become exiting on return!
 */
Uint 
erts_trace_break(Process *p, Uint *pc, Eterm *args, 
		 Uint32 *ret_flags, Eterm *tracer_pid) {
    Eterm tpid1, tpid2;
    BpDataTrace *bdt = (BpDataTrace *) pc[-4];
    
    ASSERT(pc[-5] == (Uint) BeamOp(op_i_func_info_IaaI));
    ASSERT(bdt);
    bdt = (BpDataTrace *) bdt->next;
    ASSERT(bdt);
    ASSERT(ret_flags);
    ASSERT(tracer_pid);

    ErtsSmpBPLock(bdt);
    tpid1 = tpid2 = bdt->tracer_pid;
    ErtsSmpBPUnlock(bdt);

    *ret_flags = erts_call_trace(p, pc-3/*mfa*/, bdt->match_spec, args,
				 1, &tpid2);
    *tracer_pid = tpid2;
    if (tpid1 != tpid2) {
	ErtsSmpBPLock(bdt);
	bdt->tracer_pid = tpid2;
	ErtsSmpBPUnlock(bdt);
    }
    pc[-4] = (Uint) bdt;
    return bdt->orig_instr;
}

int 
erts_set_mtrace_break(Eterm mfa[3], int specified, Binary *match_spec,
		      Eterm tracer_pid) {
    ERTS_SMP_LC_ASSERT(erts_smp_is_system_blocked(0));
    return set_break(mfa, specified, match_spec,
		     (Uint) BeamOp(op_i_mtrace_breakpoint), 0, tracer_pid);
}

int 
erts_set_mtrace_break(Eterm mfa[3], int specified, Binary *match_spec,
		      Eterm tracer_pid) {
    ERTS_SMP_LC_ASSERT(erts_smp_thr_progress_is_blocking());
    return set_break(mfa, specified, match_spec,
		     (BeamInstr) BeamOp(op_i_mtrace_breakpoint), 0, tracer_pid);
}

int erts_is_time_break(Process *p, BeamInstr *pc, Eterm *retval) {
    Uint i, ix;
    bp_time_hash_t hash;
    Uint size;
    Eterm *hp, t;
    bp_data_time_item_t *item = NULL;
    BpDataTime *bdt = (BpDataTime *) is_break(pc, (BeamInstr) BeamOp(op_i_time_breakpoint));

    if (bdt) {
	if (retval) {
	    /* collect all hashes to one hash */
	    bp_hash_init(&hash, 64);
	    /* foreach threadspecific hash */
	    for (i = 0; i < bdt->n; i++) {
		bp_data_time_item_t *sitem;

	        /* foreach hash bucket not NIL*/
		for(ix = 0; ix < bdt->hash[i].n; ix++) {
		    item = &(bdt->hash[i].item[ix]);
		    if (item->pid != NIL) {
			sitem = bp_hash_get(&hash, item);
			if (sitem) {
			    BP_TIME_ADD(sitem, item);
			} else {
			    bp_hash_put(&hash, item);
			}
		    }
		}
	    }
	    /* *retval should be NIL or term from previous bif in export entry */

	    if (hash.used > 0) {
		size = (5 + 2)*hash.used;
		hp   = HAlloc(p, size);

		for(ix = 0; ix < hash.n; ix++) {
		    item = &(hash.item[ix]);
		    if (item->pid != NIL) {
			t = TUPLE4(hp, item->pid,
				make_small(item->count),
				make_small(item->s_time),
				make_small(item->us_time));
			hp += 5;
			*retval = CONS(hp, t, *retval); hp += 2;
		    }
		}
	    }
	    bp_hash_delete(&hash);
	}
	return !0;
    }

    return 0;
}

int 
erts_is_count_break(BeamInstr *pc, Sint *count_ret) {
    BpDataCount *bdc = 
	(BpDataCount *) is_break(pc, (BeamInstr) BeamOp(op_i_count_breakpoint));
    
    if (bdc) {
	if (count_ret) {
	    *count_ret = (Sint) erts_smp_atomic_read_nob(&bdc->acount);
	}
	return !0;
    }
    return 0;
}

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_ext(&export_tables[code_ix].htable,
		      init_template(&templ, m, f, a), &fun);
    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;
}

int 
erts_is_count_break(Uint *pc, Sint *count_ret) {
    BpDataCount *bdc = 
	(BpDataCount *) is_break(pc, (Uint) BeamOp(op_i_count_breakpoint));
    
    if (bdc) {
	if (count_ret) {
	    ErtsSmpBPLock(bdc);
	    *count_ret = bdc->count;
	    ErtsSmpBPUnlock(bdc);
	}
	return !0;
    }
    return 0;
}

void
erts_bp_match_export(BpFunctions* f, ErtsCodeMFA *mfa, int specified)
{
    ErtsCodeIndex code_ix = erts_active_code_ix();
    int i;
    int num_exps = export_list_size(code_ix);
    int ne;

    f->matching = (BpFunction *) Alloc(num_exps*sizeof(BpFunction));
    ne = 0;
    for (i = 0; i < num_exps; i++) {
	Export* ep = export_list(i, code_ix);
	BeamInstr* pc;

        switch (specified) {
        case 3:
            if (mfa->arity != ep->info.mfa.arity)
                continue;
        case 2:
            if (mfa->function != ep->info.mfa.function)
                continue;
        case 1:
            if (mfa->module != ep->info.mfa.module)
                continue;
        case 0:
            break;
        default:
            ASSERT(0);
        }

	pc = ep->beam;
	if (ep->addressv[code_ix] == pc) {
	    if ((*pc == (BeamInstr) em_apply_bif ||
		 *pc == (BeamInstr) em_call_error_handler)) {
		continue;
	    }
	    ASSERT(*pc == (BeamInstr) BeamOp(op_i_generic_breakpoint));
	} else if (erts_is_function_native(erts_code_to_codeinfo(ep->addressv[code_ix]))) {
	    continue;
	}

	f->matching[ne].ci = &ep->info;
	f->matching[ne].mod = erts_get_module(ep->info.mfa.module, code_ix);
	ne++;

    }
    f->matched = ne;
}

static void
uninstall_breakpoint(BeamInstr* pc)
{
    if (*pc == (BeamInstr) BeamOp(op_i_generic_breakpoint)) {
	GenericBp* g = (GenericBp *) pc[-4];
	if (g->data[erts_active_bp_ix()].flags == 0) {
	    /*
	     * The following write is not protected by any lock. We
	     * assume that the hardware guarantees that a write of an
	     * aligned word-size (or half-word) writes is atomic
	     * (i.e. that other processes executing this code will not
	     * see a half pointer).
	     */
	    *pc = g->orig_instr;
	}
    }
}