[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, 2 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 7653447..652f519 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -907,7 +907,8 @@ void CodeGenModule::Release() {
   if (Context.getTargetInfo().getTriple().isWasm())
     EmitMainVoidAlias();
 
-  if (getTriple().isAMDGPU()) {
+  if (getTriple().isAMDGPU() ||
+      (getTriple().isSPIRV() && getTriple().getVendor() == llvm::Triple::AMD)) {
     // Emit amdhsa_code_object_version module flag, which is code object version
     // times 100.
     if (getTarget().getTargetOpts().CodeObjectVersion !=