[all-commits] [llvm/llvm-project] 4effda: [ASan] return 0 for current allocated bytes if mal...

[Chen Zheng via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 4effda09d897c165253118dae8b7580d9d276048
      https://github.com/llvm/llvm-project/commit/4effda09d897c165253118dae8b7580d9d276048
  Author: Chen Zheng <czhengsz at cn.ibm.com>
  Date:   2023-09-26 (Tue, 26 Sep 2023)

  Changed paths:
    M compiler-rt/lib/asan/asan_stats.cpp
    M compiler-rt/test/asan/TestCases/Posix/current_allocated_bytes.cpp

  Log Message:
  -----------
  [ASan] return 0 for current allocated bytes if malloc/free are never happend (#67394)

This is found during address sanitizer enablement on AIX.

On platforms that has no malloc/free calls before user's malloc/free
calls, `__sanitizer_get_current_allocated_bytes()` should return 0.
Otherwise the case like
`compiler-rt/test/sanitizer_common/TestCases/allocator_interface.cpp`
will fail at below scenario:
```
void Test(int size) { 
  auto allocated_bytes_before = __sanitizer_get_current_allocated_bytes();
  int *p = (int *)malloc(size);

  assert(__sanitizer_get_current_allocated_bytes() >=
         size + allocated_bytes_before);   // if allocated_bytes_before is 1, this assert will fail. allocated_bytes_before should be 0
}
```