Default to "nvptx[64]-unknown-cuda" triple for device-side CUDA compilation.

[tra]

Summary

Default to "nvptx[64]-unknown-cuda" triple for device-side CUDA compilation.

[eliben]

LGTM

[echristo]

Since -fcuda-is-device is just a -cc1 option can we require that the user just pass the triple in? Seems like a small shortcut that's unneeded?

-eric

[tra]

Scrapped. echristo@ has convinced me that required parameters to cc1 should not be guessed but rather provided explicitly.

lib/Frontend/CompilerInvocation.cpp

static void ParseTargetArgs(TargetOptions &Opts, ArgList &Args) {
   Opts.ABI = Args.getLastArgValue(OPT_target_abi);
   Opts.CPU = Args.getLastArgValue(OPT_target_cpu);
   Opts.FPMath = Args.getLastArgValue(OPT_mfpmath);
   Opts.FeaturesAsWritten = Args.getAllArgValues(OPT_target_feature);
   Opts.LinkerVersion = Args.getLastArgValue(OPT_target_linker_version);
   Opts.Triple = llvm::Triple::normalize(Args.getLastArgValue(OPT_triple));
 
   // Use the default target triple if unspecified.
-  if (Opts.Triple.empty())
+  if (Opts.Triple.empty()) {
+    if (Args.hasArg(OPT_fcuda_is_device)) {
+      llvm::Triple HostTriple(llvm::sys::getDefaultTargetTriple());
+      Opts.Triple = HostTriple.isArch64Bit()
+                        ? llvm::Triple::normalize("nvptx64-unknown-cuda")
+                        : llvm::Triple::normalize("nvptx-unknown-cuda");
+    } else
       Opts.Triple = llvm::sys::getDefaultTargetTriple();
   }
+}
 
 bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
                                         const char *const *ArgBegin,
                                         const char *const *ArgEnd,
                                         DiagnosticsEngine &Diags) {
   bool Success = true;
 
   // Parse the arguments.