compiler-rt/test/msan/unpoison_param.cpp

   1 // Tests that __msan_unpoison_param() works as specified.  To prevent MSan
   2 // instrumentation from modifying parameter shadow before each call to foo(), we
   3 // compile main() without MSan.
   4
   5 // RUN: %clangxx_msan -fno-sanitize=memory -c %s -o %t-main.o
   6 // RUN: %clangxx_msan -fno-sanitize-memory-param-retval %t-main.o %s -o %t
   7 // RUN: %run %t
   8
   9 #include <assert.h>
  10 #include <sanitizer/msan_interface.h>
  11
  12 #if __has_feature(memory_sanitizer)
  13
  14 __attribute__((noinline)) int bar(int a, int b) {
  15   volatile int zero = 0;
  16   return zero;
  17 }
  18
  19 int foo(int a, int b, int unpoisoned_params) {
  20   if (unpoisoned_params == 0) {
  21     assert(__msan_test_shadow(&a, sizeof(a)) == 0);
  22     assert(__msan_test_shadow(&b, sizeof(b)) == 0);
  23   } else if (unpoisoned_params == 1) {
  24     assert(__msan_test_shadow(&a, sizeof(a)) == -1);
  25     assert(__msan_test_shadow(&b, sizeof(b)) == 0);
  26   } else if (unpoisoned_params == 2) {
  27     assert(__msan_test_shadow(&a, sizeof(a)) == -1);
  28     assert(__msan_test_shadow(&b, sizeof(b)) == -1);
  29   }
  30
  31   // Poisons parameter shadow in TLS so that the next call from uninstrumented
  32   // main has params 1 and 2 poisoned no matter what.
  33   int x, y;
  34   return bar(x, y);
  35 }
  36
  37 #else
  38
  39 int foo(int, int, int);
  40
  41 int main() {
  42   foo(0, 0, 2); // Poison parameters for next call.
  43   foo(0, 0, 0); // Check that both params are poisoned.
  44   __msan_unpoison_param(1);
  45   foo(0, 0, 1); // Check that only first param is unpoisoned.
  46   __msan_unpoison_param(2);
  47   foo(0, 0, 2); // Check that first and second params are unpoisoned.
  48   return 0;
  49 }
  50
  51 #endif