compiler-rt/test/asan/TestCases/alloca_loop_unpoisoning.cpp

   1 // RUN: %clangxx_asan -O0 -mllvm -asan-instrument-dynamic-allocas %s -o %t
   2 // RUN: %env_asan_opts=detect_stack_use_after_return=0 %run %t 2>&1
   3 //
   4 // REQUIRES: stable-runtime
   5
   6 // This testcase checks that allocas and VLAs inside loop are correctly unpoisoned.
   7
   8 #include <assert.h>
   9 #include <stdint.h>
  10 #include <stdlib.h>
  11 #include "sanitizer/asan_interface.h"
  12
  13 // MSVC provides _alloca instead of alloca.
  14 #if defined(_MSC_VER) && !defined(alloca)
  15 # define alloca _alloca
  16 #endif
  17
  18 #if defined(__sun__) && defined(__svr4__)
  19 #include <alloca.h>
  20 #endif
  21
  22 void *top, *bot;
  23
  24 __attribute__((noinline)) void foo(int len) {
  25   char x;
  26   top = &x;
  27   volatile char array[len];
  28   if (len)
  29     array[0] = 0;
  30   assert(!(reinterpret_cast<uintptr_t>(array) & 31L));
  31   alloca(len);
  32   for (int i = 0; i < 32; ++i) {
  33     volatile char array[i];
  34     if (i)
  35       array[0] = 0;
  36     bot = alloca(i);
  37     assert(!(reinterpret_cast<uintptr_t>(bot) & 31L));
  38   }
  39 }
  40
  41 int main(int argc, char **argv) {
  42   foo(32);
  43   void *q = __asan_region_is_poisoned(bot, (char *)top - (char *)bot);
  44   assert(!q);
  45   return 0;
  46 }