Create an empty directory for -o and -reproduce.

[ruiu]

Summary

Create an empty directory for -o and -reproduce.

lld/ELF/Driver.cpp

void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
   readConfigs(Args);
   initLLVM(Args);
   createFiles(Args);
   inferMachineType();
   checkOptions(Args);
   if (ErrorCount)
     return;
 
+  // If -o contains a directory, create the directory in the tar archive
+  // so that "lld @response.txt" won't fail. This is for -reproduce.
+  if (Tar && !Config->OutputFile.empty()) {
+    SmallString<256> S(Config->OutputFile);
+    sys::path::remove_filename(S);
+
+    // Tar files cannot contain empty directoreis,
+    // so create a dummy file instead.
+    if (!S.empty())
+      Tar->append((S + "/.keep").str(), "");
+  }
+
   switch (Config->EKind) {
   case ELF32LEKind:
     link<ELF32LE>(Args);
     return;
   case ELF32BEKind:
     link<ELF32BE>(Args);
     return;
   case ELF64LEKind:

lld/ELF/DriverUtils.cpp

std::string elf::createResponseFile(const opt::InputArgList &Args) {
   // Copy the command line to the output while rewriting paths.
   for (auto *Arg : Args) {
     switch (Arg->getOption().getID()) {
     case OPT_reproduce:
       break;
     case OPT_INPUT:
       OS << quote(rewritePath(Arg->getValue())) << "\n";
       break;
-    case OPT_o:
-      // If -o path contains directories, "lld @response.txt" will likely
-      // fail because the archive we are creating doesn't contain empty
-      // directories for the output path (-o doesn't create directories).
-      // Strip directories to prevent the issue.
-      OS << "-o " << quote(sys::path::filename(Arg->getValue())) << "\n";
-      break;
     case OPT_L:
+    case OPT_alias_script_T:
     case OPT_dynamic_list:
+    case OPT_o:
     case OPT_rpath:
-    case OPT_alias_script_T:
     case OPT_script:
     case OPT_version_script:
       OS << Arg->getSpelling() << " " << quote(rewritePath(Arg->getValue()))
          << "\n";
       break;
     default:
       OS << toString(Arg) << "\n";
     }

lld/test/ELF/reproduce.s

 # CHECK:      repro2/response.txt
 # CHECK-NEXT: repro2/version.txt
 # CHECK-NEXT: repro2/{{.*}}/dyn
 # CHECK-NEXT: repro2/{{.*}}/ver
 # CHECK-NEXT: repro2/{{.*}}/foo bar
 # CHECK-NEXT: repro2/{{.*}}/file2
 # CHECK-NEXT: repro2/{{.*}}/file
 
-## Check that directory path is stripped from -o <file-path>
+## Check that we create a directory for -o.
 # RUN: mkdir -p %t.dir/build3/a/b/c
 # RUN: cd %t.dir
 # RUN: ld.lld build1/foo.o -o build3/a/b/c/bar -shared --as-needed --reproduce repro3.tar
-# RUN: tar xf repro3.tar
-# RUN: FileCheck %s --check-prefix=RSP3 < repro3/response.txt
-# RSP3: -o bar
+# RUN: tar tf repro3.tar | FileCheck --check-prefix=RSP3 %s
+# RSP3: repro3/build3/a/b/c/.keep
 
 .globl _start
 _start:
   mov $60, %rax
   mov $42, %rdi
   syscall