compiler-rt/test/msan/allocator_mapping.cpp

   1 // Test that a module constructor can not map memory over the MSan heap
   2 // (without MAP_FIXED, of course). Current implementation ensures this by
   3 // mapping the heap early, in __msan_init.
   4 //
   5 // RUN: %clangxx_msan -O0 %s -o %t_1
   6 // RUN: %clangxx_msan -O0 -DHEAP_ADDRESS=$(%run %t_1) %s -o %t_2 && %run %t_2
   7 //
   8 // This test only makes sense for the 64-bit allocator. The 32-bit allocator
   9 // does not have a fixed mapping. Exclude platforms that use the 32-bit
  10 // allocator.
  11 // UNSUPPORTED: target-is-mips64,target-is-mips64el,target=aarch64{{.*}}
  12
  13 #include <assert.h>
  14 #include <stdio.h>
  15 #include <sys/mman.h>
  16 #include <stdlib.h>
  17
  18 #ifdef HEAP_ADDRESS
  19 struct A {
  20   A() {
  21     void *const hint = reinterpret_cast<void *>(HEAP_ADDRESS);
  22     void *p = mmap(hint, 4096, PROT_READ | PROT_WRITE,
  23                    MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  24     // This address must be already mapped. Check that mmap() succeeds, but at a
  25     // different address.
  26     assert(p != reinterpret_cast<void *>(-1));
  27     assert(p != hint);
  28   }
  29 } a;
  30 #endif
  31
  32 int main() {
  33   void *p = malloc(10);
  34   printf("0x%zx\n", reinterpret_cast<size_t>(p) & (~0xfff));
  35   free(p);
  36 }