[flang-commits] [clang] [flang] [flang][Driver] Enables lto-partitions and fat-lto-object. (PR #158125)

[Tarun Prabhu via flang-commits]

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@@ -182,6 +182,29 @@ void Flang::addCodegenOptions(const ArgList &Args,
     CmdArgs.push_back("-fcoarray");
 }
 
+void Flang::addLTOOptions(const ArgList &Args, ArgStringList &CmdArgs) const {
+  const ToolChain &TC = getToolChain();
+  const Driver &D = TC.getDriver();
+  DiagnosticsEngine &Diags = D.getDiags();
+  LTOKind LTOMode = D.getLTOMode();
+  // LTO mode is parsed by the Clang driver library.
+  assert(LTOMode != LTOK_Unknown && "Unknown LTO mode.");
+  if (LTOMode == LTOK_Full)
+    CmdArgs.push_back("-flto=full");
+  else if (LTOMode == LTOK_Thin) {
+    Diags.Report(
+        Diags.getCustomDiagID(DiagnosticsEngine::Warning,
+                              "the option '-flto=thin' is a work in progress"));
+    CmdArgs.push_back("-flto=thin");
+  }
+  if (Args.hasArg(options::OPT_flto_partitions_EQ)) {
+    StringRef A = Args.getLastArgValue(options::OPT_flto_partitions_EQ, "8");
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tarunprabhu wrote:

Is the default of 8 here taken from clang? If so, we should probably mention that in a comment, or, better still, share this value between clang and flang. If it is specific to flang, it may be worth mentioning why 8, or pointing to some documentation where this choice is described.

https://github.com/llvm/llvm-project/pull/158125