Index: include/lldb/Host/FileSpec.h
===================================================================
--- include/lldb/Host/FileSpec.h
+++ include/lldb/Host/FileSpec.h
@@ -265,7 +265,7 @@
     ///     will be added.
     //------------------------------------------------------------------
     void
-    Dump(Stream *s, bool trailing_slash = true) const;
+    Dump(Stream *s) const;
 
     //------------------------------------------------------------------
     /// Existence test.
@@ -638,6 +638,7 @@
     static void Normalize(llvm::SmallVectorImpl<char> &path, PathSyntax syntax = ePathSyntaxHostNative);
     static void DeNormalize(llvm::SmallVectorImpl<char> &path, PathSyntax syntax = ePathSyntaxHostNative);
 
+    char GetPathSeparator() const;
 
     //------------------------------------------------------------------
     /// Run through the input string, replaying the effect of any ".." and produce
Index: source/Host/common/FileSpec.cpp
===================================================================
--- source/Host/common/FileSpec.cpp
+++ source/Host/common/FileSpec.cpp
@@ -276,6 +276,16 @@
     std::replace(path.begin(), path.end(), '/', '\\');
 }
 
+char
+FileSpec::GetPathSeparator() const
+{
+    if (m_syntax == ePathSyntaxPosix ||
+        (m_syntax == ePathSyntaxHostNative && FileSystem::GetNativePathSyntax() == ePathSyntaxPosix))
+        return '/';
+
+    return '\\';
+}
+
 //------------------------------------------------------------------
 // Update the contents of this object with a new path. The path will
 // be split up into a directory and filename and stored as uniqued
@@ -609,15 +619,17 @@
 // directory delimiter, and the filename.
 //------------------------------------------------------------------
 void
-FileSpec::Dump(Stream *s, bool trailing_slash) const
+FileSpec::Dump(Stream *s) const
 {
     if (s)
     {
-        m_directory.Dump(s);
-        if ((m_filename || trailing_slash) && m_directory &&
-                !m_directory.GetStringRef().endswith("/"))
-            s->PutChar('/');
-        m_filename.Dump(s);
+        // Dump guarantees that directory-only paths will have a path separator
+        // appended.  GetPath() guarantees that directory-only paths will not have
+        // a path separator appended.  So it's safe to just append one.
+        std::string path = GetPath();
+        if (!m_filename && !path.empty())
+            path.push_back(GetPathSeparator());
+        s->PutCString(path.c_str());
     }
 }
 
@@ -816,10 +828,25 @@
 void
 FileSpec::GetPath(llvm::SmallVectorImpl<char> &path, bool denormalize) const
 {
-    StreamString stream;
-    Dump(&stream, false);
-    path.append(stream.GetString().begin(), stream.GetString().end());
-    Normalize(path, m_syntax);
+    if (m_directory)
+    {
+        llvm::StringRef dir = m_directory.GetStringRef();
+        // Don't add any trailing slashes, even if `m_directory` has one.  This
+        // will guarantee that GetPath() returns paths with no trailing slash if
+        // there is no filename.  If there is a filename, we will join the directory
+        // and file with a slash later.
+        dir = dir.rtrim("/\\");
+        path.append(dir.begin(), dir.end());
+    }
+
+    if (m_filename)
+    {
+        if (m_directory)
+            path.push_back('/');
+        llvm::StringRef file = m_filename.GetStringRef();
+        path.append(file.begin(), file.end());
+    }
+
     if (denormalize && !path.empty())
         DeNormalize(path, m_syntax);
 }