Index: lld/COFF/Driver.h
===================================================================
--- lld/COFF/Driver.h
+++ lld/COFF/Driver.h
@@ -21,6 +21,7 @@
 #include "llvm/Object/COFF.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
+#include "llvm/Support/FileSystem.h"
 #include "llvm/Support/TarWriter.h"
 #include <memory>
 #include <set>
@@ -126,6 +127,13 @@
   std::vector<MemoryBufferRef> Resources;
 
   llvm::StringSet<> DirectivesExports;
+
+  bool equivalentPath(StringRef A, StringRef B);
+  llvm::sys::fs::file_status getFileStatus(StringRef Path);
+
+  // Pathnames to their stat() results. Since stat() is slow,
+  // we want to cache.
+  llvm::DenseMap<StringRef, llvm::sys::fs::file_status> StatCache;
 };
 
 // Functions below this line are defined in DriverUtils.cpp.
Index: lld/COFF/Driver.cpp
===================================================================
--- lld/COFF/Driver.cpp
+++ lld/COFF/Driver.cpp
@@ -128,6 +128,15 @@
                              bool WholeArchive) {
   StringRef Filename = MB->getBufferIdentifier();
 
+  // A file shouldn't be parsed more than once even if it is
+  // represented in different paths.
+  for (StringRef Path : FilePaths) {
+    if (equivalentPath(Path, Filename)) {
+      warn(Filename + ": object specified more than once");
+      return;
+    }
+  }
+
   MemoryBufferRef MBRef = takeBuffer(std::move(MB));
   FilePaths.push_back(Filename);
 
@@ -775,6 +784,23 @@
   TaskQueue.push_back(std::move(Task));
 }
 
+bool LinkerDriver::equivalentPath(StringRef A, StringRef B) {
+  return sys::fs::equivalent(getFileStatus(A), getFileStatus(B));
+}
+
+// A cached warpper for stat().
+sys::fs::file_status LinkerDriver::getFileStatus(StringRef Path) {
+  auto It = StatCache.find(Path);
+  if (It != StatCache.end())
+    return It->second;
+
+  // We ignore an error as we'll report it when we try to open a file.
+  sys::fs::file_status Ret;
+  sys::fs::status(Path, Ret);
+  StatCache[Path] = Ret;
+  return Ret;
+}
+
 bool LinkerDriver::run() {
   ScopedTimer T(InputFileTimer);
 
@@ -1231,22 +1257,25 @@
   if (errorCount())
     return;
 
-  bool WholeArchiveFlag = Args.hasArg(OPT_wholearchive_flag);
+  // A predicate returning true if a given path is an argument for
+  // /wholearchive:, or /wholearchive is enabled globally.
+  // This function is a bit tricky because "foo.obj /wholearchive:././foo.obj"
+  // needs to be handled as "/wholearchive:foo.obj foo.obj".
+  auto IsWholeArchive = [&](StringRef Path) {
+    if (Args.hasArg(OPT_wholearchive_flag))
+      return true;
+    for (auto *Arg : Args.filtered(OPT_wholearchive_file))
+      if (equivalentPath(Path, Arg->getValue()))
+        return true;
+    return false;
+  };
+
   // Create a list of input files. Files can be given as arguments
   // for /defaultlib option.
-  std::vector<MemoryBufferRef> MBs;
-  for (auto *Arg : Args.filtered(OPT_INPUT, OPT_wholearchive_file)) {
-    switch (Arg->getOption().getID()) {
-    case OPT_INPUT:
-      if (Optional<StringRef> Path = findFile(Arg->getValue()))
-        enqueuePath(*Path, WholeArchiveFlag);
-      break;
-    case OPT_wholearchive_file:
-      if (Optional<StringRef> Path = findFile(Arg->getValue()))
-        enqueuePath(*Path, true);
-      break;
-    }
-  }
+  for (auto *Arg : Args.filtered(OPT_INPUT, OPT_wholearchive_file))
+    if (Optional<StringRef> Path = findFile(Arg->getValue()))
+      enqueuePath(*Path, IsWholeArchive(Arg->getValue()));
+
   for (auto *Arg : Args.filtered(OPT_defaultlib))
     if (Optional<StringRef> Path = findLib(Arg->getValue()))
       enqueuePath(*Path, false);
Index: lld/test/COFF/wholearchive.s
===================================================================
--- lld/test/COFF/wholearchive.s
+++ lld/test/COFF/wholearchive.s
@@ -10,6 +10,14 @@
 # RUN: lld-link -dll -out:%t.dll -entry:main %t.main.obj -wholearchive %t.archive.lib -implib:%t.lib
 # RUN: llvm-readobj %t.lib | FileCheck %s -check-prefix CHECK-IMPLIB
 
+# RUN: lld-link -dll -out:%t.dll -entry:main %t.main.obj %t.archive.lib -wholearchive:%t.archive.lib -implib:%t.lib
+# RUN: llvm-readobj %t.lib | FileCheck %s -check-prefix CHECK-IMPLIB
+
+# RUN: mkdir -p %t.dir
+# RUN: cp %t.archive.lib %t.dir/foo.lib
+# RUN: lld-link -dll -out:%t.dll -entry:main %t.main.obj %t.dir/./foo.lib -wholearchive:%t.dir/foo.lib -implib:%t.lib
+# RUN: llvm-readobj %t.lib | FileCheck %s -check-prefix CHECK-IMPLIB
+
 # CHECK-IMPLIB: Symbol: __imp_exportfn3
 # CHECK-IMPLIB: Symbol: exportfn3