HIP is a C++ Runtime API and Kernel Language that allows developers to create portable applications for AMD and NVIDIA GPUs from single source code. Contributors wishing to submit new HIP Features (ie functions, classes, types) should resemble CUDA APIs.
Differences or limitations of HIP APIs as compared to CUDA APIs should be clearly documented and described.
Some guidelines are outlined below:
### Add a new HIP API ###
- Add a translation to the hipify-clang tool ; many examples abound.
- For stat tracking purposes, place the API into an appropriate stat category ("dev", "mem", "stream", etc).
- Add a inlined NVIDIA implementation for the function in /hipnv/include/hip/nvidia_detail/nvidia_hip_runtime_api.h in the repository [hipother](https://github.com/ROCm/hipother).
- These are typically headers
- Add an HIP definition and Doxygen comments for the function in /include/hip/hip_runtime_api.h, in the repository [hip](https://github.com/ROCm/hip).
- Source implementation typically go in clr/hipamd/src/hip_*.cpp in the reposotory [clr](https://github.com/ROCm/clr). The implementation involves calls to HIP runtime (ie for hipStream_t).
### Run Unit Tests ###
For new features or bug fixes, it's mandatory to run associate [hip-tests](https://github.com/ROCm/hip-tests).
Please go to the repo and follow the steps.
For applications and benchmarks outside the hip-tests environment, developments should use a two-step development flow:
-#1. Compile, link, and install HIP. See {ref}`Building the HIP runtime` notes.
-#2. Relink the target application to include changes in HIP runtime file.
## Coding Style ##
- Code Indentation:
- Tabs should be expanded to spaces.
- Use 4 spaces indentation.
- Capitalization and Naming
- Prefer camelCase for HIP interfaces and internal symbols. Note HCC uses _ for separator.
- Member variables should begin with a leading "_". This allows them to be easily distinguished from other variables or functions.
-`{}` placement
- namespace should be on same line as `{` and separated by a space.
- Single-line if statement should still use `{/}` pair (even though C++ does not require).
- For functions, the opening `{` should be placed on a new line.
- For if/else blocks, the opening `{` is placed on same line as the if/else. Use a space to separate `{` from if/else. For example,
```console
if (foo) {
doFoo()
} else {
doFooElse();
}
```
- Miscellaneous
- All references in function parameter lists should be const.
- "ihip" means internal hip structures. These should not be exposed through the HIP API.
- Keyword TODO refers to a note that should be addressed in long-term. Could be style issue, software architecture, or known bugs.
- FIXME refers to a short-term bug that needs to be addressed.
-`HIP_INIT_API()` should be placed at the start of each top-level HIP API. This function will make sure the HIP runtime is initialized, and also constructs an appropriate API string for tracing and CodeXL marker tracing. The arguments to HIP_INIT_API should match those of the parent function.
-`hipExtGetLastError()` can be called as the AMD platform specific API, to return error code from last HIP API called from the active host thread. `hipGetLastError()` and `hipPeekAtLastError()` can also return the last error that was returned by any of the HIP runtime calls in the same host thread.
- All HIP environment variables should begin with the keyword HIP_
Environment variables should be long enough to describe their purpose but short enough so they can be remembered - perhaps 10-20 characters, with 3-4 parts separated by underscores.
To see the list of current environment variables, along with their values, set HIP_PRINT_ENV and run any hip applications on ROCm platform.
HIPCC or other tools may support additional environment variables which should follow the above convention.
## Pull Request Guidelines ##
By creating a pull request, you agree to the statements made in the code license section. Your pull request should target the default branch. Our current default branch is the develop branch, which serves as our integration branch.
Follow existing best practice for writing a good Git commit message.
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
```
### Process ###
After you create a PR, you can take a look at a diff of the changes you made using the PR's "Files" tab.
PRs must pass through the checks and the code review described in the [Acceptance Criteria](#acceptance-criteria) section before they can be merged.
Checks may take some time to complete. You can view their progress in the table near the bottom of the pull request page. You may also be able to use the links in the table
to view logs associated with a check if it fails.
During code reviews, another developer will take a look through your proposed change. If any modifications are requested (or further discussion about anything is
needed), they may leave a comment. You can follow up and respond to the comment, and/or create comments of your own if you have questions or ideas.
When a modification request has been completed, the conversation thread about it will be marked as resolved.
To update the code in your PR (eg. in response to a code review discussion), you can simply push another commit to the branch used in your pull request.
### Doxygen Editing Guidelines ###
- bugs should be marked with @bugs near the code where the bug might be fixed. The @bug message will appear in the API description and also in the
