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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include <stdint.h>
     18 #include <stdlib.h>
     19 #include <crt_priv.h>
     20 
     21 static void callVectors(const void *from_addr, const void *to_addr)
     22 {
     23     typedef void (* const callVect)(void);
     24     callVect *start = (callVect *)from_addr;
     25     callVect *end = (callVect *)to_addr;
     26     const int32_t step = from_addr < to_addr ? 1 : -1;
     27     const int32_t count = step > 0 ? end - start : start - end;
     28 
     29     // basic sanity check
     30     if (&start[step * count] != end)
     31         return;
     32 
     33     for (; start != end; start += step) {
     34         callVect vec = *start;
     35         if (vec != NULL)
     36             vec();
     37     }
     38 }
     39 
     40 void __crt_init(void)
     41 {
     42     extern uint32_t __init_array_start[];
     43     extern uint32_t __init_array_end[];
     44 
     45     callVectors(__init_array_start, __init_array_end);
     46 }
     47 
     48 void __crt_exit(void)
     49 {
     50     extern uint32_t __fini_array_start[];
     51     extern uint32_t __fini_array_end[];
     52     extern uint32_t __bss_end[];
     53     extern uint32_t __got_start[];
     54 
     55     // call global destructors
     56     callVectors(__fini_array_start, __fini_array_end);
     57     if (&__fini_array_end[1] <= __got_start) {
     58         // call registered static destructors
     59         callVectors(__bss_end + __fini_array_end[0] * (sizeof(uint32_t)), __bss_end);
     60     }
     61 }
     62