[clang] [Clang] Rework creating offloading toolchains (PR #125556)

[Joseph Huber via cfe-commits]

================
@@ -3441,91 +3455,25 @@ class OffloadingActionBuilder final {
         return true;
       }
 
-      ToolChains.push_back(
-          AssociatedOffloadKind == Action::OFK_Cuda
-              ? C.getSingleOffloadToolChain<Action::OFK_Cuda>()
-              : C.getSingleOffloadToolChain<Action::OFK_HIP>());
-
-      CompileHostOnly = C.getDriver().offloadHostOnly();
-      EmitLLVM = Args.getLastArg(options::OPT_emit_llvm);
-      EmitAsm = Args.getLastArg(options::OPT_S);
-
-      // --offload and --offload-arch options are mutually exclusive.
-      if (Args.hasArgNoClaim(options::OPT_offload_EQ) &&
-          Args.hasArgNoClaim(options::OPT_offload_arch_EQ,
-                             options::OPT_no_offload_arch_EQ)) {
-        C.getDriver().Diag(diag::err_opt_not_valid_with_opt) << "--offload-arch"
-                                                             << "--offload";
-      }
-
-      // Collect all offload arch parameters, removing duplicates.
       std::set<StringRef> GpuArchs;
-      bool Error = false;
-      const ToolChain &TC = *ToolChains.front();
-      for (Arg *A : C.getArgsForToolChain(&TC, /*BoundArch=*/"",
-                                          AssociatedOffloadKind)) {
-        if (!(A->getOption().matches(options::OPT_offload_arch_EQ) ||
-              A->getOption().matches(options::OPT_no_offload_arch_EQ)))
-          continue;
-        A->claim();
-
-        for (StringRef ArchStr : llvm::split(A->getValue(), ",")) {
-          if (A->getOption().matches(options::OPT_no_offload_arch_EQ) &&
-              ArchStr == "all") {
-            GpuArchs.clear();
-          } else if (ArchStr == "native") {
-            auto GPUsOrErr = ToolChains.front()->getSystemGPUArchs(Args);
-            if (!GPUsOrErr) {
-              TC.getDriver().Diag(diag::err_drv_undetermined_gpu_arch)
-                  << llvm::Triple::getArchTypeName(TC.getArch())
-                  << llvm::toString(GPUsOrErr.takeError()) << "--offload-arch";
-              continue;
-            }
+      for (Action::OffloadKind Kind : {Action::OFK_Cuda, Action::OFK_HIP}) {
+        auto TCRange = C.getOffloadToolChains(Kind);
+        for (auto &I : llvm::make_range(TCRange)) {
+          ToolChains.push_back(I.second);
 
-            for (auto GPU : *GPUsOrErr) {
-              GpuArchs.insert(Args.MakeArgString(GPU));
-            }
-          } else {
-            ArchStr = getCanonicalOffloadArch(ArchStr);
-            if (ArchStr.empty()) {
-              Error = true;
-            } else if (A->getOption().matches(options::OPT_offload_arch_EQ))
-              GpuArchs.insert(ArchStr);
-            else if (A->getOption().matches(options::OPT_no_offload_arch_EQ))
-              GpuArchs.erase(ArchStr);
-            else
-              llvm_unreachable("Unexpected option.");
-          }
+          for (auto Arch : C.getDriver().OffloadArchs.lookup(I.second))
+            GpuArchs.insert(Arch);
----------------
jhuber6 wrote:

I will probably move this back to when we create the job actions after this patch, the `OffloadArchs` global was only necessary when I had to 'precompute' a few conflicting architectures (like if someone did --offload-arch=sm_89,gfx1030 -fopenmp) because it creates two toolchains that would then share that option. I work around that here by modifying the derived argument list.

https://github.com/llvm/llvm-project/pull/125556