1 files changed, 41 insertions, 2 deletions
diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index cdfefde52df..07b5f8bea06 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -422,6 +422,46 @@ static std::string getMapFile(const opt::InputArgList &Args) {
   return (OutFile.substr(0, OutFile.rfind('.')) + ".map").str();
 }
 
+static bool isBitcodeFile(StringRef Path) {
+  std::unique_ptr<MemoryBuffer> MB = check(
+      MemoryBuffer::getFile(Path, -1, false, true), "could not open " + Path);
+  StringRef Buf = MB->getBuffer();
+  return sys::fs::identify_magic(Buf) == sys::fs::file_magic::bitcode;
+}
+
+// Create response file contents and invoke the MSVC linker.
+void LinkerDriver::invokeMSVC(opt::InputArgList &Args) {
+  std::string Rsp = "/nologo ";
+
+  for (auto *Arg : Args) {
+    switch (Arg->getOption().getID()) {
+    case OPT_linkrepro:
+    case OPT_lldmap:
+    case OPT_lldmap_file:
+    case OPT_msvclto:
+      // LLD-specific options are stripped.
+      break;
+    case OPT_opt:
+      if (!StringRef(Arg->getValue()).startswith("lld"))
+        Rsp += toString(Arg) + " ";
+      break;
+    case OPT_INPUT:
+      // Bitcode files are stripped as they've been compiled to
+      // native object files.
+      if (Optional<StringRef> Path = doFindFile(Arg->getValue()))
+        if (isBitcodeFile(*Path))
+          break;
+      Rsp += quote(Arg->getValue()) + " ";
+      break;
+    default:
+      Rsp += toString(Arg) + " ";
+    }
+  }
+
+  std::vector<StringRef> ObjectFiles = Symtab.compileBitcodeFiles();
+  runMSVCLinker(Rsp, ObjectFiles);
+}
+
 void LinkerDriver::enqueueTask(std::function<void()> Task) {
   TaskQueue.push_back(std::move(Task));
 }
@@ -820,8 +860,7 @@ void LinkerDriver::link(ArrayRef<const char *> ArgsArr) {
   // If /msvclto is given, we use the MSVC linker to link LTO output files.
   // This is useful because MSVC link.exe can generate complete PDBs.
   if (Args.hasArg(OPT_msvclto)) {
-    std::vector<StringRef> ObjectFiles = Symtab.compileBitcodeFiles();
-    runMSVCLinker(Args, ObjectFiles);
+    invokeMSVC(Args);
     exit(0);
   }