forked from OSchip/llvm-project
9fa5e3280d
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
|
||
|---|---|---|
| .. | ||
| cmake/Modules | ||
| deviceRTLs | ||
| include | ||
| plugins | ||
| src | ||
| test | ||
| utils | ||
| CMakeLists.txt | ||
| README.txt | ||
README.txt
README for the LLVM* OpenMP* Offloading Runtime Library (libomptarget)
======================================================================
How to Build the LLVM* OpenMP* Offloading Runtime Library (libomptarget)
========================================================================
In-tree build:
$ cd where-you-want-to-live
Check out openmp (libomptarget lives under ./libomptarget) into llvm/projects
$ cd where-you-want-to-build
$ mkdir build && cd build
$ cmake path/to/llvm -DCMAKE_C_COMPILER=<C compiler> -DCMAKE_CXX_COMPILER=<C++ compiler>
$ make omptarget
Out-of-tree build:
$ cd where-you-want-to-live
Check out openmp (libomptarget lives under ./libomptarget)
$ cd where-you-want-to-live/openmp/libomptarget
$ mkdir build && cd build
$ cmake path/to/openmp -DCMAKE_C_COMPILER=<C compiler> -DCMAKE_CXX_COMPILER=<C++ compiler>
$ make
For details about building, please look at README.rst in the parent directory.
Architectures Supported
=======================
The current library has been only tested in Linux operating system and the
following host architectures:
* Intel(R) 64 architecture
* IBM(R) Power architecture (big endian)
* IBM(R) Power architecture (little endian)
* ARM(R) AArch64 architecture (little endian)
The currently supported offloading device architectures are:
* Intel(R) 64 architecture (generic 64-bit plugin - mostly for testing purposes)
* IBM(R) Power architecture (big endian) (generic 64-bit plugin - mostly for testing purposes)
* IBM(R) Power architecture (little endian) (generic 64-bit plugin - mostly for testing purposes)
* ARM(R) AArch64 architecture (little endian) (generic 64-bit plugin - mostly for testing purposes)
* CUDA(R) enabled 64-bit NVIDIA(R) GPU architectures
Supported RTL Build Configurations
==================================
Supported Architectures: Intel(R) 64, IBM(R) Power 7 and Power 8
---------------------------
| gcc | clang |
--------------|------------|------------|
| Linux* OS | Yes(1) | Yes(2) |
-----------------------------------------
(1) gcc version 4.8.2 or later is supported.
(2) clang version 3.7 or later is supported.
Front-end Compilers that work with this RTL
===========================================
The following compilers are known to do compatible code generation for
this RTL:
- clang (from https://github.com/clang-ykt )
- clang (development branch at http://clang.llvm.org - several features still
under development)
-----------------------------------------------------------------------
Notices
=======
This library and related compiler support is still under development, so the
employed interface is likely to change in the future.
*Other names and brands may be claimed as the property of others.