Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -2283,12 +2283,30 @@
                        ArgStringList &CmdArgs) {
   CmdArgs.push_back(Args.MakeArgString(getCompilerRT(TC, "builtins")));
 
-  if (!TC.getTriple().isOSWindows()) {
-    // FIXME: why do we link against gcc when we are using compiler-rt?
-    CmdArgs.push_back("-lgcc_s");
-    if (TC.getDriver().CCCIsCXX())
-      CmdArgs.push_back("-lgcc_eh");
+  if (TC.getTriple().isOSWindows())
+    return;
+
+  // FIXME: Get default library from each target/os.
+  // From here on, we assume this is a GNU target. Even if it's not GNU/Linux,
+  // the system toolchain is assumed GNU based, which could be wrong based on
+  // the OS and/or the Arch.
+
+  // Get other libraries, to only include what's necessary and avoid
+  // duplication of symbols.
+  bool HasLibUnwind = false, HasLibCxxAbi = false;
+  for (const Arg *A : Args.filtered(options::OPT_l)) {
+    StringRef Value = A->getValue();
+    if (Value == "unwind")
+      HasLibUnwind = true;
+    if (Value == "c++abi")
+      HasLibCxxAbi = true;
   }
+  // If we're including -lunwind, don't include -lgcc_s
+  if (!HasLibUnwind)
+    CmdArgs.push_back("-lgcc_s");
+  // If we're including -lc++abi, don't include -lgcc_eh
+  if (!HasLibCxxAbi && TC.getDriver().CCCIsCXX())
+    CmdArgs.push_back("-lgcc_eh");
 }
 
 static void addProfileRT(const ToolChain &TC, const ArgList &Args,
Index: test/Driver/linux-ld.c
===================================================================
--- test/Driver/linux-ld.c
+++ test/Driver/linux-ld.c
@@ -1556,3 +1556,76 @@
 // CHECK-ARMV7EB: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
 // CHECK-ARMV7EB: "--be8"
 // CHECK-ARMV7EB: "-m" "armebelf_linux_eabi"
+
+// Test libunwind / libc++abi with compiler-rt (x86_64/ARM/AArch64)
+
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=x86_64-linux-gnu \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTGNU %s
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=x86_64-linux-gnu \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt -lunwind 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTUNW %s
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=x86_64-linux-gnu \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt -lc++abi 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTCXX %s
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=x86_64-linux-gnu \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt -lunwind -lc++abi 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTALL %s
+
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=armv7-linux-gnueabihf \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTGNU %s
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=armv7-linux-gnueabihf \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt -lunwind 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTUNW %s
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=armv7-linux-gnueabihf \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt -lc++abi 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTCXX %s
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=armv7-linux-gnueabihf \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt -lunwind -lc++abi 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTALL %s
+
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=aarch64-linux-gnu \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTGNU %s
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=aarch64-linux-gnu \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt -lunwind 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTUNW %s
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=aarch64-linux-gnu \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt -lc++abi 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTCXX %s
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o \
+// RUN:     --target=aarch64-linux-gnu \
+// RUN:     --driver-mode=g++ --rtlib=compiler-rt -lunwind -lc++abi 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RTALL %s
+
+// CHECK-RTGNU: "{{.*}}ld{{(.exe)?}}"
+// CHECK-RTGNU: "-lgcc_s"
+// CHECK-RTGNU: libclang_rt.builtins-{{.*}}.a
+// CHECK-RTGNU: "-lgcc_eh"
+
+// CHECK-RTUNW: "{{.*}}ld{{(.exe)?}}"
+// CHECK-RTUNW: "-lunwind"
+// CHECK-RTUNW: libclang_rt.builtins-{{.*}}.a
+// CHECK-RTUNW: "-lgcc_eh"
+
+// CHECK-RTCXX: "{{.*}}ld{{(.exe)?}}"
+// CHECK-RTCXX: "-lc++abi"
+// CHECK-RTCXX: libclang_rt.builtins-{{.*}}.a
+// CHECK-RTCXX: "-lgcc_s"
+
+// CHECK-RTALL: "{{.*}}ld{{(.exe)?}}"
+// CHECK-RTALL: "-lunwind"
+// CHECK-RTALL: "-lc++abi"
+// CHECK-RTALL: libclang_rt.builtins-{{.*}}.a