[OpenMP] Fix delete map type in ref count debug messages

For example, without this patch:

```
$ cat test.c
int main() {
  int x;
  #pragma omp target enter data map(alloc: x)
  #pragma omp target enter data map(alloc: x)
  #pragma omp target enter data map(alloc: x)
  #pragma omp target exit data map(delete: x)
  ;
  return 0;
}
$ clang -fopenmp -fopenmp-targets=nvptx64-nvidia-cuda test.c
$ LIBOMPTARGET_DEBUG=1 ./a.out |& grep 'Creating\|Mapping exists\|last'
Libomptarget --> Creating new map entry with HstPtrBegin=0x00007ffddf1eaea8, TgtPtrBegin=0x00000000013bb040, Size=4, RefCount=1, Name=unknown
Libomptarget --> Mapping exists with HstPtrBegin=0x00007ffddf1eaea8, TgtPtrBegin=0x00000000013bb040, Size=4, RefCount=2 (incremented), Name=unknown
Libomptarget --> Mapping exists with HstPtrBegin=0x00007ffddf1eaea8, TgtPtrBegin=0x00000000013bb040, Size=4, RefCount=3 (incremented), Name=unknown
Libomptarget --> Mapping exists with HstPtrBegin=0x00007ffddf1eaea8, TgtPtrBegin=0x00000000013bb040, Size=4, RefCount=2 (decremented)
Libomptarget --> There are 4 bytes allocated at target address 0x00000000013bb040 - is not last
```

`RefCount` is reported as decremented to 2, but it ought to be reset
because of the `delete` map type, and `is not last` is incorrect.

This patch migrates the reset of reference counts from
`DeviceTy::deallocTgtPtr` to `DeviceTy::getTgtPtrBegin`, which then
correctly reports the reset.  Based on the `IsLast` result from
`DeviceTy::getTgtPtrBegin`, `targetDataEnd` then correctly reports `is
last` for any deletion.  `DeviceTy::deallocTgtPtr` is responsible only
for the final reference count decrement and mapping removal.

An obscure side effect of this patch is that a `delete` map type when
the reference count is infinite yields `DelEntry=IsLast=false` in
`targetDataEnd` and so no longer results in a
`DeviceTy::deallocTgtPtr` call.  Without this patch, that call is a
no-op anyway besides some unnecessary locking and mapping table
lookups.

Reviewed By: grokos

Differential Revision: https://reviews.llvm.org/D104560

0 files changed, 0 insertions, 0 deletions