[clang][Driver] Add HIPAMD Driver support for AMDGCN flavoured SPIR-V (#95061)

This patch augments the HIPAMD driver to allow it to target AMDGCN
flavoured SPIR-V compilation. It's mostly straightforward, as we re-use
some of the existing SPIRV infra, however there are a few notable
additions:

- we introduce an `amdgcnspirv` offload arch, rather than relying on
using `generic` (this is already fairly overloaded) or simply using
`spirv` or `spirv64` (we'll want to use these to denote unflavoured
SPIRV, once we bring up that capability)
- initially it is won't be possible to mix-in SPIR-V and concrete AMDGPU
targets, as it would require some relatively intrusive surgery in the
HIPAMD Toolchain and the Driver to deal with two triples
(`spirv64-amd-amdhsa` and `amdgcn-amd-amdhsa`, respectively)
- in order to retain user provided compiler flags and have them
available at JIT time, we rely on embedding the command line via
`-fembed-bitcode=marker`, which the bitcode writer had previously not
implemented for SPIRV; we only allow it conditionally for AMDGCN
flavoured SPIRV, and it is handled correctly by the Translator (it ends
up as a string literal)

Once the SPIRV BE is no longer experimental we'll switch to using that
rather than the translator. There's some additional work that'll come
via a separate PR around correctly piping through AMDGCN's
implementation of `printf`, for now we merely handle its flags
correctly.

1 files changed, 1 insertions, 0 deletions

diff --git a/clang/lib/Basic/Cuda.cpp b/clang/lib/Basic/Cuda.cpp
index 1d96a92..af99c4d 100644
--- a/clang/lib/Basic/Cuda.cpp
+++ b/clang/lib/Basic/Cuda.cpp
@@ -148,6 +148,7 @@ static const CudaArchToStringMap arch_names[] = {
     {CudaArch::GFX12_GENERIC, "gfx12-generic", "compute_amdgcn"},
     GFX(1200), // gfx1200
     GFX(1201), // gfx1201
+    {CudaArch::AMDGCNSPIRV, "amdgcnspirv", "compute_amdgcn"},
     {CudaArch::Generic, "generic", ""},
     // clang-format on
 };