src/compiler-rt/test/asan/TestCases/alloca_loop_unpoisoning.cc

   1 // RUN: %clangxx_asan -O0 -mllvm -asan-instrument-allocas %s -o %t
   2 // RUN: %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 void *top, *bot;
  19
  20 __attribute__((noinline)) void foo(int len) {
  21   char x;
  22   top = &x;
  23   char array[len];  // NOLINT
  24   assert(!(reinterpret_cast<uintptr_t>(array) & 31L));
  25   alloca(len);
  26   for (int i = 0; i < 32; ++i) {
  27     char array[i];  // NOLINT
  28     bot = alloca(i);
  29     assert(!(reinterpret_cast<uintptr_t>(bot) & 31L));
  30   }
  31 }
  32
  33 int main(int argc, char **argv) {
  34   foo(32);
  35   void *q = __asan_region_is_poisoned(bot, (char *)top - (char *)bot);
  36   assert(!q);
  37   return 0;
  38 }