diff --git a/include/swift/Driver/ToolChain.h b/include/swift/Driver/ToolChain.h
index 7be6dffbe37cf..60aa1fd99836e 100644
--- a/include/swift/Driver/ToolChain.h
+++ b/include/swift/Driver/ToolChain.h
@@ -249,6 +249,14 @@ class ToolChain {
   const Driver &getDriver() const { return D; }
   const llvm::Triple &getTriple() const { return Triple; }
 
+  /// Special handling for passing down '-l' arguments.
+  ///
+  /// Not all downstream tools (lldb, ld etc.) consistently accept
+  /// a space between the '-l' flag and its argument, so we remove
+  /// the extra space if it was present in \c Args.
+  static void addLinkedLibArgs(const llvm::opt::ArgList &Args,
+                               llvm::opt::ArgStringList &FrontendArgs);
+
   /// Construct a Job for the action \p JA, taking the given information into
   /// account.
   ///
diff --git a/include/swift/Option/Options.td b/include/swift/Option/Options.td
index 3e83fc623a7e7..0e498ccddf932 100644
--- a/include/swift/Option/Options.td
+++ b/include/swift/Option/Options.td
@@ -701,7 +701,7 @@ def libc : Separate<["-"], "libc">, HelpText<"libc runtime library to use">;
 
 def linker_option_Group : OptionGroup<"<linker-specific options>">;
 
-def l : Joined<["-"], "l">, Group<linker_option_Group>,
+def l : JoinedOrSeparate<["-"], "l">, Group<linker_option_Group>,
     Flags<[FrontendOption, DoesNotAffectIncrementalBuild]>,
     HelpText<"Specifies a library which should be linked against">;
 def framework : Separate<["-"], "framework">, Group<linker_option_Group>,
diff --git a/lib/Driver/DarwinToolChains.cpp b/lib/Driver/DarwinToolChains.cpp
index e4047e2839ed4..af322a56f496b 100644
--- a/lib/Driver/DarwinToolChains.cpp
+++ b/lib/Driver/DarwinToolChains.cpp
@@ -796,7 +796,9 @@ toolchains::Darwin::constructInvocation(const DynamicLinkJobAction &job,
   Arguments.push_back("-no_objc_category_merging");
 
   // These custom arguments should be right before the object file at the end.
-  context.Args.AddAllArgs(Arguments, options::OPT_linker_option_Group);
+  context.Args.AddAllArgsExcept(Arguments, {options::OPT_linker_option_Group},
+                                {options::OPT_l});
+  ToolChain::addLinkedLibArgs(context.Args, Arguments);
   context.Args.AddAllArgValues(Arguments, options::OPT_Xlinker);
 
   // This should be the last option, for convenience in checking output.
diff --git a/lib/Driver/ToolChain.cpp b/lib/Driver/ToolChain.cpp
index 522a9727c454a..525af62dd2b56 100644
--- a/lib/Driver/ToolChain.cpp
+++ b/lib/Driver/ToolChain.cpp
@@ -287,6 +287,15 @@ mergeBatchInputs(ArrayRef<const Job *> jobs,
   return false;
 }
 
+void ToolChain::addLinkedLibArgs(const llvm::opt::ArgList &Args,
+                                 llvm::opt::ArgStringList &FrontendArgs) {
+  Args.getLastArg(options::OPT_l);
+  for (auto Arg : Args.getAllArgValues(options::OPT_l)) {
+    const std::string lArg("-l" + Arg);
+    FrontendArgs.push_back(Args.MakeArgString(Twine(lArg)));
+  }
+}
+
 /// Construct a \c BatchJob by merging the constituent \p jobs' CommandOutput,
 /// input \c Job and \c Action members. Call through to \c constructInvocation
 /// on \p BatchJob, to build the \c InvocationInfo.
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index f11fed94301a7..ae5306538f915 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -142,6 +142,7 @@ static void addLTOArgs(const OutputInfo &OI, ArgStringList &arguments) {
   }
 }
 
+
 void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
                                       const CommandOutput &output,
                                       const ArgList &inputArgs,
@@ -842,7 +843,8 @@ ToolChain::constructInvocation(const InterpretJobAction &job,
   Arguments.push_back("-module-name");
   Arguments.push_back(context.Args.MakeArgString(context.OI.ModuleName));
 
-  context.Args.AddAllArgs(Arguments, options::OPT_l, options::OPT_framework);
+  context.Args.AddAllArgs(Arguments, options::OPT_framework);
+  ToolChain::addLinkedLibArgs(context.Args, Arguments);
 
   // The immediate arguments must be last.
   context.Args.AddLastArg(Arguments, options::OPT__DASH_DASH);
@@ -1190,8 +1192,8 @@ ToolChain::constructInvocation(const REPLJobAction &job,
   addRuntimeLibraryFlags(context.OI, FrontendArgs);
 
   context.Args.AddLastArg(FrontendArgs, options::OPT_import_objc_header);
-  context.Args.AddAllArgs(FrontendArgs, options::OPT_l, options::OPT_framework,
-                          options::OPT_L);
+  context.Args.AddAllArgs(FrontendArgs, options::OPT_framework, options::OPT_L);
+  ToolChain::addLinkedLibArgs(context.Args, FrontendArgs);
 
   if (!useLLDB) {
     FrontendArgs.insert(FrontendArgs.begin(), {"-frontend", "-repl"});
diff --git a/lib/Driver/UnixToolChains.cpp b/lib/Driver/UnixToolChains.cpp
index 30905f6b72253..1dc32acfd8357 100644
--- a/lib/Driver/UnixToolChains.cpp
+++ b/lib/Driver/UnixToolChains.cpp
@@ -358,7 +358,9 @@ toolchains::GenericUnix::constructInvocation(const DynamicLinkJobAction &job,
   }
 
   // These custom arguments should be right before the object file at the end.
-  context.Args.AddAllArgs(Arguments, options::OPT_linker_option_Group);
+  context.Args.AddAllArgsExcept(Arguments, {options::OPT_linker_option_Group},
+                                {options::OPT_l});
+  ToolChain::addLinkedLibArgs(context.Args, Arguments);
   context.Args.AddAllArgs(Arguments, options::OPT_Xlinker);
   context.Args.AddAllArgValues(Arguments, options::OPT_Xclang_linker);
 
diff --git a/lib/Driver/WindowsToolChains.cpp b/lib/Driver/WindowsToolChains.cpp
index b3567bf969b11..5001fa33fd2a5 100644
--- a/lib/Driver/WindowsToolChains.cpp
+++ b/lib/Driver/WindowsToolChains.cpp
@@ -179,7 +179,9 @@ toolchains::Windows::constructInvocation(const DynamicLinkJobAction &job,
   }
 
   context.Args.AddAllArgs(Arguments, options::OPT_Xlinker);
-  context.Args.AddAllArgs(Arguments, options::OPT_linker_option_Group);
+  context.Args.AddAllArgsExcept(Arguments, {options::OPT_linker_option_Group},
+                                {options::OPT_l});
+  ToolChain::addLinkedLibArgs(context.Args, Arguments);
   context.Args.AddAllArgValues(Arguments, options::OPT_Xclang_linker);
 
   // Run clang in verbose mode if "-v" is set
diff --git a/test/Driver/linker-library-with-space.swift b/test/Driver/linker-library-with-space.swift
new file mode 100644
index 0000000000000..b4497301147d6
--- /dev/null
+++ b/test/Driver/linker-library-with-space.swift
@@ -0,0 +1,18 @@
+// RUN: %swiftc_driver -sdk "" -driver-print-jobs -target x86_64-unknown-linux-gnu -Ffoo -Fsystem car -F cdr -framework bar -Lbaz -lboo -Xlinker -undefined %s 2>&1 > %t.linux.txt
+// RUN: %FileCheck -check-prefix LINUX-lib-flag-space %s < %t.linux.txt
+
+// LINUX-lib-flag-space: swift
+// LINUX-lib-flag-space: -o [[OBJECTFILE:.*]]
+
+// LINUX-lib-flag-space: clang{{(\.exe)?"? }}
+// LINUX-lib-flag-space-DAG: -pie
+// LINUX-lib-flag-space-DAG: [[OBJECTFILE]]
+// LINUX-lib-flag-space-DAG: -lswiftCore
+// LINUX-lib-flag-space-DAG: -L [[STDLIB_PATH:[^ ]+(/|\\\\)lib(/|\\\\)swift(/|\\\\)]]
+// LINUX-lib-flag-space-DAG: -Xlinker -rpath -Xlinker [[STDLIB_PATH]]
+// LINUX-lib-flag-space-DAG: -F foo -iframework car -F cdr
+// LINUX-lib-flag-space-DAG: -framework bar
+// LINUX-lib-flag-space-DAG: -L baz
+// LINUX-lib-flag-space-DAG: -lboo
+// LINUX-lib-flag-space-DAG: -Xlinker -undefined
+// LINUX-lib-flag-space: -o main
diff --git a/test/Driver/linker.swift b/test/Driver/linker.swift
index 2282192c66250..4f36bf7eada78 100644
--- a/test/Driver/linker.swift
+++ b/test/Driver/linker.swift
@@ -1,6 +1,8 @@
 // Must be able to run xcrun-return-self.sh
 // REQUIRES: shell
 // REQUIRES: rdar65281056
+// FIXME: When this is turned on, please move the test from linker-library-with-space.swift
+// to this file and remove that file.
 // RUN: %swiftc_driver -sdk "" -driver-print-jobs -target x86_64-apple-macosx10.9 %s 2>&1 > %t.simple.txt
 // RUN: %FileCheck %s < %t.simple.txt
 // RUN: %FileCheck -check-prefix SIMPLE %s < %t.simple.txt
diff --git a/test/Driver/options-repl.swift b/test/Driver/options-repl.swift
index 118ebd7b834f9..52646ae073fab 100644
--- a/test/Driver/options-repl.swift
+++ b/test/Driver/options-repl.swift
@@ -16,7 +16,7 @@
 
 
 // RUN: %swift_driver -sdk "" -lldb-repl -### | %FileCheck -check-prefix=LLDB %s
-// RUN: %swift_driver -sdk "" -lldb-repl -D A -DB -D C -DD -L /path/to/libraries -L /path/to/more/libraries -F /path/to/frameworks -lsomelib -framework SomeFramework -sdk / -I "this folder" -module-name Test -target %target-triple -### | %FileCheck -check-prefix=LLDB-OPTS %s
+// RUN: %swift_driver -sdk "" -lldb-repl -D A -DB -D C -DD -L /path/to/libraries -L /path/to/more/libraries -F /path/to/frameworks -lsomelib -l otherlib -framework SomeFramework -sdk / -I "this folder" -module-name Test -target %target-triple -### | %FileCheck -check-prefix=LLDB-OPTS %s
 
 // LLDB: lldb{{(\.exe)?"?}} {{"?}}--repl=
 // LLDB-NOT: -module-name
@@ -30,6 +30,7 @@
 // LLDB-OPTS-DAG: -L /path/to/more/libraries
 // LLDB-OPTS-DAG: -F /path/to/frameworks
 // LLDB-OPTS-DAG: -lsomelib
+// LLDB-OPTS-DAG: -lotherlib
 // LLDB-OPTS-DAG: -framework SomeFramework
 // LLDB-OPTS-DAG: -I \"this folder\"
 // LLDB-OPTS: "