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

   1 // RUN: %clangxx_asan -O0 -mllvm -asan-instrument-dynamic-allocas %s -o %t
   2 // RUN: %run %t 2>&1
   3 //
   4 // REQUIRES: stable-runtime
   5
   6 // See https://github.com/llvm/llvm-project/issues/110956
   7 // XFAIL: target=sparc{{.*}}
   8
   9 // This testcase checks correct interaction between VLAs and allocas.
  10
  11 #include <assert.h>
  12 #include <stdint.h>
  13 #include <stdlib.h>
  14 #include "sanitizer/asan_interface.h"
  15
  16 // MSVC provides _alloca instead of alloca.
  17 #if defined(_MSC_VER) && !defined(alloca)
  18 # define alloca _alloca
  19 #endif
  20
  21 #if defined(__sun__) && defined(__svr4__)
  22 #include <alloca.h>
  23 #endif
  24
  25 #define RZ 32
  26
  27 __attribute__((noinline)) void foo(int len) {
  28   char *top, *bot;
  29   // This alloca call should live until the end of foo.
  30   char *alloca1 = (char *)alloca(len);
  31   assert(!(reinterpret_cast<uintptr_t>(alloca1) & 31L));
  32   // This should be first poisoned address after loop.
  33   top = alloca1 - RZ;
  34   for (int i = 0; i < 32; ++i) {
  35     // Check that previous alloca was unpoisoned at the end of iteration.
  36     if (i) assert(!__asan_region_is_poisoned(bot, 96));
  37     // VLA is unpoisoned at the end of iteration.
  38     volatile char array[i];
  39     // Ensure that asan-use-stack-safety does not optimize out the poisoning.
  40     if (i) array[0] = 0;
  41     assert(!(reinterpret_cast<uintptr_t>(array) & 31L));
  42     // Alloca is unpoisoned at the end of iteration,
  43     // because dominated by VLA.
  44     bot = (char *)alloca(i) - RZ;
  45   }
  46   // Check that all allocas from loop were unpoisoned correctly.
  47   void *q = __asan_region_is_poisoned(bot, (char *)top - (char *)bot + 1);
  48   assert(q == top);
  49 }
  50
  51 int main(int argc, char **argv) {
  52   foo(32);
  53   return 0;
  54 }