[llvm-ar] Remove leading slash when printing thin archive members

[ruiu]

LGTM

Thanks you for doing this!

llvm/test/tools/llvm-ar/print-thin-archive-path.test

11 ↗

(On Diff #185629)

Make sure that this file ends with a newline character.

llvm/trunk/test/tools/llvm-ar/print-thin-archive-path.test

+RUN: mkdir -p %t/foo
+RUN: touch %t/foo/a.txt
+RUN: rm -f %t/foo/archive.a
+
+RUN: cd %t && llvm-ar rcST foo/archive.a foo/a.txt
+RUN: cd %t && llvm-ar t foo/archive.a | FileCheck %s --match-full-lines --check-prefix=PARENT-DIR
+RUN: cd %t/foo && llvm-ar t archive.a | FileCheck %s --match-full-lines --check-prefix=CHILD-DIR
+
+PARENT-DIR: foo/a.txt
+CHILD-DIR:  a.txt

llvm/trunk/tools/llvm-ar/llvm-ar.cpp

if (Verbose) {
     // nanoseconds.
     // TODO: fix format_provider<TimePoint<>> to allow other units.
     sys::TimePoint<> ModTimeInNs = ModTimeOrErr.get();
     outs() << ' ' << formatv("{0:%b %e %H:%M %Y}", ModTimeInNs);
     outs() << ' ';
   }
 
   if (C.getParent()->isThin()) {
-    outs() << sys::path::parent_path(ArchiveName);
-    outs() << '/';
+    StringRef ParentDir = sys::path::parent_path(ArchiveName);
+    if (!ParentDir.empty())
+      outs() << ParentDir << '/';
   }
   outs() << Name << "\n";
 }
 
 // Implement the 'x' operation. This function extracts files back to the file
 // system.
 static void doExtract(StringRef Name, const object::Archive::Child &C) {
   // Retain the original mode.