[clang] [Clang][NFC] Clean up fetching the offloading toolchain (PR #125095)

[Artem Belevich via cfe-commits]

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@@ -6601,6 +6573,72 @@ std::string Driver::GetClPchPath(Compilation &C, StringRef BaseName) const {
   return std::string(Output);
 }
 
+const ToolChain &Driver::getOffloadToolChain(
+    const llvm::opt::ArgList &Args, const Action::OffloadKind Kind,
+    const llvm::Triple &Target, const llvm::Triple &AuxTarget) const {
+  auto &TC = ToolChains[Target.str() + "/" + AuxTarget.str()];
+  auto &HostTC = ToolChains[AuxTarget.str()];
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Artem-B wrote:

I think it would be useful here to spell out the type `std::unique_ptr<ToolChain>`. Otherwise, the `if(!TC)` and `TC= ...` blow look *very* suspicious.


https://github.com/llvm/llvm-project/pull/125095