[flang] Add dependent-lib option to flang -fc1 on Windows (#72121)

This patch adds a --dependent-lib option to flang -fc1 on Windows to
embed library link options into the object file. This is needed to
properly select the Windows CRT to link against.

1 files changed, 23 insertions, 0 deletions

diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index 334da3a..cb4f2d6 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -1054,6 +1054,27 @@ static bool parseVScaleArgs(CompilerInvocation &invoc, llvm::opt::ArgList &args,
   return true;
 }
 
+static bool parseLinkerOptionsArgs(CompilerInvocation &invoc,
+                                   llvm::opt::ArgList &args,
+                                   clang::DiagnosticsEngine &diags) {
+  llvm::Triple triple = llvm::Triple(invoc.getTargetOpts().triple);
+
+  // TODO: support --dependent-lib on other platforms when MLIR supports
+  //       !llvm.dependent.lib
+  if (args.hasArg(clang::driver::options::OPT_dependent_lib) &&
+      !triple.isOSWindows()) {
+    const unsigned diagID =
+        diags.getCustomDiagID(clang::DiagnosticsEngine::Error,
+                              "--dependent-lib is only supported on Windows");
+    diags.Report(diagID);
+    return false;
+  }
+
+  invoc.getCodeGenOpts().DependentLibs =
+      args.getAllArgValues(clang::driver::options::OPT_dependent_lib);
+  return true;
+}
+
 bool CompilerInvocation::createFromArgs(
     CompilerInvocation &res, llvm::ArrayRef<const char *> commandLineArgs,
     clang::DiagnosticsEngine &diags, const char *argv0) {
@@ -1163,6 +1184,8 @@ bool CompilerInvocation::createFromArgs(
 
   success &= parseVScaleArgs(res, args, diags);
 
+  success &= parseLinkerOptionsArgs(res, args, diags);
+
   // Set the string to be used as the return value of the COMPILER_OPTIONS
   // intrinsic of iso_fortran_env. This is either passed in from the parent
   // compiler driver invocation with an environment variable, or failing that