[clang] [flang] [flang][Driver] Support -gsplit-dwarf. (PR #160540)

[Tom Eccles via cfe-commits]

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@@ -131,20 +135,57 @@ void Flang::addOtherOptions(const ArgList &Args, ArgStringList &CmdArgs) const {
                    options::OPT_finstrument_functions});
 
   llvm::codegenoptions::DebugInfoKind DebugInfoKind;
+  bool hasDwarfNArg = getDwarfNArg(Args) != nullptr;
   if (Args.hasArg(options::OPT_gN_Group)) {
     Arg *gNArg = Args.getLastArg(options::OPT_gN_Group);
     DebugInfoKind = debugLevelToInfoKind(*gNArg);
-  } else if (Args.hasArg(options::OPT_g_Group)) {
+  } else if (Args.hasArg(options::OPT_g_Flag) || hasDwarfNArg) {
     DebugInfoKind = llvm::codegenoptions::FullDebugInfo;
   } else {
     DebugInfoKind = llvm::codegenoptions::NoDebugInfo;
   }
   addDebugInfoKind(CmdArgs, DebugInfoKind);
-  if (getDwarfNArg(Args)) {
+  if (hasDwarfNArg) {
     const unsigned DwarfVersion = getDwarfVersion(getToolChain(), Args);
     CmdArgs.push_back(
         Args.MakeArgString("-dwarf-version=" + Twine(DwarfVersion)));
   }
+  if (Args.hasArg(options::OPT_gsplit_dwarf) ||
+      Args.hasArg(options::OPT_gsplit_dwarf_EQ)) {
+    // FIXME: -gsplit-dwarf on AIX is currently unimplemented.
+    if (TC.getTriple().isOSAIX()) {
+      D.Diag(diag::err_drv_unsupported_opt_for_target)
+          << Args.getLastArg(options::OPT_gsplit_dwarf)->getSpelling()
+          << TC.getTriple().str();
+      return;
+    }
+    if (DebugInfoKind == llvm::codegenoptions::NoDebugInfo)
+      return;
+
+    Arg *SplitDWARFArg;
+    DwarfFissionKind DwarfFission = getDebugFissionKind(D, Args, SplitDWARFArg);
+
+    if (DwarfFission == DwarfFissionKind::None ||
+        !checkDebugInfoOption(SplitDWARFArg, Args, D, TC))
+      return;
+
+    if (!TC.getTriple().isOSBinFormatELF() &&
+        !TC.getTriple().isOSBinFormatWasm() &&
+        !TC.getTriple().isOSBinFormatCOFF())
+      return;
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tblah wrote:

Do you think we should warn in cases where split dwarf cannot be done instead of silently ignoring?

https://github.com/llvm/llvm-project/pull/160540