The AMD fork aims to contain all of upstream LLVM, and also includes several AMD-specific additions in the llvm-project/amd directory:

• amd/comgr - The Code Object Manager API, designed to simplify linking, compiling, and inspecting code objects (code owner: @lamb-j)
• amd/device-libs -The sources and CMake build system for a set of AMD-specific device-side language runtime libraries (code owner: @b-sumner)
• amd/hipcc - A compiler driver utility that wraps clang and passes the appropriate include and library options for the target compiler and HIP infrastructure (code owner: @david-salinas)

See the README files in respective subdirectories for more information on these AMD-specific projects. While the AMD fork aims to otherwise follow upstream as closely as possible, there are several outstanding differences.

• OpenMP - The AMD fork contains several changes:

  • Additional optimizations for OpenMP offload
  • Host-exec services for printing on-device and doing malloc/free from device
  • Improved support for OMPT, the OpenMP tools interface
  • Driver improvements for multi-image and Target ID features
  • OMPD support, implements OpenMP D interfaces.
  • ASAN support for OpenMP.
  • MI300A Unified Shared Memory support

• Heterogeneous Debugging - A prototype of debug-info supporting AMDGPU targets, affecting most parts of the compiler, is implemented as documented in docs/AMDGPULLVMExtensionsForHeterogeneousDebugging.rst but is an ongoing work-in-progress. Fundamental changes are expected as parts of the design are adapted for upstreaming.

• Address Sanitizer - Changes were added to santizer_common and asan libraries in compiler-rt to support AMD GPU address sanitizer error detection and reports. These changes are intended to be upstreamed. The instrumentation pass changes have already been upstreamed.

• Reverted Patches - For upstream patches that break internal testing, we may temporarily revert these patches until the testing issues are resolved. We maintain a list of reverted upstream patches in llvm-project/revert_patches.txt.