The runtime-wrappers depend on LLVMSupport, pulling in static initialization code (e.g. command line arguments). Dynamically loading multiple such libraries results in ODR violoations.
So far this has not been an issue, but in D94421, I would like to load both the async-runtime and the cuda-runtime-wrappers as part of a cuda-runner integration test. When doing this, code that asserts that an option category is only registered once fails (note that I've only experienced this in Google's bazel where the async-runtime depends on LLVMSupport, but a similar issue would happen in cmake if more than one runtime-wrapper starts to depend on LLVMSupport).
The underlying issue is that we have a mix of static and dynamic linking. If all dependencies were loaded as shared objects (i.e. if LLVMSupport was linked dynamically to the runtime wrappers), each dependency would only get loaded once. However, linking dependencies dynamically would require special attention to paths (one could dynamically load the dependencies first given explicit paths). The simpler approach seems to be to link all dependencies statically into a single shared object.
This change basically applies the same logic that we have in the c_runner_utils: we have a shared object target that can be loaded dynamically, and we have a static library target that can be linked to other runtime-wrapper shared object targets.
Reviewed By: herhut
Differential Revision: https://reviews.llvm.org/D94399
Summary:
`mlir-rocm-runner` is introduced in this commit to execute GPU modules on ROCm
platform. A small wrapper to encapsulate ROCm's HIP runtime API is also inside
the commit.
Due to behavior of ROCm, raw pointers inside memrefs passed to `gpu.launch`
must be modified on the host side to properly capture the pointer values
addressable on the GPU.
LLVM MC is used to assemble AMD GCN ISA coming out from
`ConvertGPUKernelToBlobPass` to binary form, and LLD is used to produce a shared
ELF object which could be loaded by ROCm HIP runtime.
gfx900 is the default target be used right now, although it could be altered via
an option in `mlir-rocm-runner`. Future revisions may consider using ROCm Agent
Enumerator to detect the right target on the system.
Notice AMDGPU Code Object V2 is used in this revision. Future enhancements may
upgrade to AMDGPU Code Object V3.
Bitcode libraries in ROCm-Device-Libs, which implements math routines exposed in
`rocdl` dialect are not yet linked, and is left as a TODO in the logic.
Reviewers: herhut
Subscribers: mgorny, tpr, dexonsmith, mehdi_amini, rriddle, jpienaar, shauheen, antiagainst, nicolasvasilache, csigg, arpith-jacob, mgester, lucyrfox, aartbik, liufengdb, stephenneuendorffer, Joonsoo, grosul1, frgossen, Kayjukh, jurahul, llvm-commits
Tags: #mlir, #llvm
Differential Revision: https://reviews.llvm.org/D80676
Christian Sigg