Support setting default value for -rtlib at build time

[zlei]

Summary

This patch introduces a new cmake variable: CLANG_DEFAULT_RTLIB, thru
which we can specify a default value for -rtlib (libgcc or
compiler-rt) at build time, just like how we set the default C++
stdlib thru CLANG_DEFAULT_CXX_STDLIB.

With these two options, we can configure clang to build binaries on
Linux that have no runtime dependence on any gcc libs (libstdc++ or
libgcc_s).

[Hahnfeld]

In general the idea looks good and takes this point off my personal todo list :-)

With the changes applied and configured with CLANG_DEFAULT_RTLIB=compiler-rt some tests fail so you may have to adapt the idea of -rtlib=platform for the tests.

Just a minor comment: Please include the full context in your diff as explained in the docs: http://llvm.org/docs/Phabricator.html#requesting-a-review-via-the-web-interface
This makes reviewing easier because one can browse the surrounding code ;-)

lib/Driver/ToolChain.cpp

530

What I dislike here is that it falls back to the platform default if the specified argument value is invalid regardless of what was configured. This may be surprising for the user as he gets a different behaviour when specifiying -rtlib=bla than completely omitting.

I just added a comment explaining how this works in GetCXXStdlibType. Maybe you can adapt its idea?

[beanz]

One small comment on the CMake code.

CMakeLists.txt

210

You'll want this to be:

set(CLANG_DEFAULT_RTLIB "" CACHE STRING "Default runtime library to use (libgcc or compiler-rt)" FORCE)

Cached variables can only be overwritten by a FORCE.

[zlei]

In D22663#494460, @Hahnfeld wrote:

With the changes applied and configured with CLANG_DEFAULT_RTLIB=compiler-rt some tests fail so you may have to adapt the idea of -rtlib=platform for the tests.

Got it. And I also need to fix those failing tests by adding -rtlib=platform to them, right?

CMakeLists.txt

210

Sorry, I'm not very familiar with cmake. But why isn't CLANG_DEFAULT_CXX_STDLIB declared with FORCE? Should I fix it as well?

lib/Driver/ToolChain.cpp

530

If you give an invalid value to -rtlib, clang should just abort and give you an error message, instead of falling back to the platform default. I see that's also how -stdlib behaves.

Or maybe I misunderstood your point?

[Hahnfeld]

In D22663#495728, @zlei wrote:

In D22663#494460, @Hahnfeld wrote:

With the changes applied and configured with CLANG_DEFAULT_RTLIB=compiler-rt some tests fail so you may have to adapt the idea of -rtlib=platform for the tests.

Got it. And I also need to fix those failing tests by adding -rtlib=platform to them, right?

Right, I think the tests should pass regardless of what default is selected (which currently is no completely true for CLANG_DEFAULT_CXX_STDLIB because it makes test/Driver/darwin-stdlib.cpp fail)

CMakeLists.txt

210

That's a matter of what we want: without FORCE the value will only be reset for that single execution of CMake and not be updated in the cache!

This is what I think is correct: The user should be repeatedly reminded that he isn't getting what he originally requested...

lib/Driver/ToolChain.cpp

530

Ehm yes, you are completely right.

For -rtlib=platform it should then be enough to write if (A && LibName != "platform") to not emit the error in this case. We could later use the same approach to simplify handling of -stdlib...

[zlei]

Support a new option -rtlib=platform for internal use, and fix tests that previously failed when configured with CLANG_DEFAULT_RTLIB=compiler-rt.

[zlei]

CMakeLists.txt

218

I think the original code for resetting CLANG_DEFAULT_CXX_STDLIB doesn't work as expected, as beanz pointed out.

In this revision, I just disable invalid values for both CLANG_DEFAULT_CXX_STDLIB and CLANG_DEFAULT_RTLIB. Users will get a error message when assigning unsupported values to them.

[Hahnfeld]

CMakeLists.txt

218

I tested it this morning and it works as (at least I) expected: It will temporarily reset the value and warn the user that the parameter is not valid.

I'm against erroring out here because there actually is a sane default value...

[zlei]

CMakeLists.txt

218

I don't have a strong opinion on this, but the problem is the original line set(CLANG_DEFAULT_CXX_STDLIB "") doesn't have actual effect (it seems to me).

I'm not sure what you mean by "temporarily reset the value". Last time I tested it, -DCLANG_DEFAULT_CXX_STDLIB=blah doesn't reset the value to an empty string (as expected?)

Anyway, I'm fine with either warning or erroring :)

[Hahnfeld]

There is also the other way round: CLANG_DEFAULT_RTLIB=libgcc shows that Darwin doesn't support that and gets a SIGSEGV (because it doesn't expect it to be libgcc without an option to be set, hehe)

Based on some GetCXXStdlibType for toolchains that only support one -stdlib, I think we can just override GetRuntimeLibType here

diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index f05261a..610285e 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -403,18 +403,23 @@ void DarwinClang::AddLinkSanitizerLibArgs(const ArgList &Args,
       /*AddRPath*/ true);
 }
 
+ToolChain::RuntimeLibType DarwinClang::GetRuntimeLibType(
+    const ArgList &Args) const {
+  if (Arg* A = Args.getLastArg(options::OPT_rtlib_EQ)) {
+    StringRef Value = A->getValue();
+    if (Value != "compiler-rt")
+      getDriver().Diag(diag::err_drv_unsupported_rtlib_for_platform)
+          << Value << "darwin";
+  }
+
+  return ToolChain::RLT_CompilerRT;
+}
+
 void DarwinClang::AddLinkRuntimeLibArgs(const llvm::Triple &EffectiveTriple,
                                         const ArgList &Args,
                                         ArgStringList &CmdArgs) const {
-  // Darwin only supports the compiler-rt based runtime libraries.
-  switch (GetRuntimeLibType(Args)) {
-  case ToolChain::RLT_CompilerRT:
-    break;
-  default:
-    getDriver().Diag(diag::err_drv_unsupported_rtlib_for_platform)
-        << Args.getLastArg(options::OPT_rtlib_EQ)->getValue() << "darwin";
-    return;
-  }
+  // Call once to ensure diagnostic is printed if wrong value was specified
+  GetRuntimeLibType(Args);
 
   // Darwin doesn't support real static executables, don't link any runtime
   // libraries with -static.
diff --git a/lib/Driver/ToolChains.h b/lib/Driver/ToolChains.h
index 25dae72..d36a799 100644
--- a/lib/Driver/ToolChains.h
+++ b/lib/Driver/ToolChains.h
@@ -575,6 +575,8 @@ public:
   /// @name Apple ToolChain Implementation
   /// {
 
+  RuntimeLibType GetRuntimeLibType(const llvm::opt::ArgList &Args) const override;
+
   void AddLinkRuntimeLibArgs(const llvm::Triple &EffectiveTriple,
                              const llvm::opt::ArgList &Args,
                              llvm::opt::ArgStringList &CmdArgs) const override;
diff --git a/test/Driver/mips-mti-linux.c b/test/Driver/mips-mti-linux.c
index e3560e2..4835d79 100644
--- a/test/Driver/mips-mti-linux.c
+++ b/test/Driver/mips-mti-linux.c
@@ -8,7 +8,7 @@
 
 // = Big-endian, mips32r2, hard float
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mips-mti-linux -mips32r2 -mhard-float \
+// RUN:     --target=mips-mti-linux -mips32r2 -mhard-float -rtlib=platform \
 // RUN:     --sysroot=%S/Inputs/mips_mti_linux/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-BE-HF-32R2 %s
 //
@@ -26,7 +26,7 @@
 
 // = Little-endian, mips32r2, hard float
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mips-mti-linux -mips32r2 -EL -mhard-float \
+// RUN:     --target=mips-mti-linux -mips32r2 -EL -mhard-float -rtlib=platform \
 // RUN:     --sysroot=%S/Inputs/mips_mti_linux/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-LE-HF-32R2 %s
 //

CMakeLists.txt

218

It means that you will still see CLANG_DEFAULT_CXX_STDLIB=blah in CMakeCache.txt but it will be temporarily set to "" when CMake builds the Makefiles.

Let's have @beanz decide on that: He is the master of CMake and I can only say that it is working as I wanted it to do ;-)

[beanz]

CMakeLists.txt

218

The first set call shouldn't be forced because you want to allow users to manually specify the value. If you were to set FORCE on it it would always overwrite any value specified on the command line.

The second set is debatable one way or the other. The CMake will function correctly with or without the set being forced, however as @Hahnfeld commented the invalid value will remain in the CMake cache. That means that every time CMake is re-run the warning will get printed, and the value will be overridden within the scope of that execution.

I think it is better to FORCE the second set so that the cache gets overwritten with a valid value and the warning only gets logged the first time CMake is run. That said, I don't really have a strong opinion here, so do whatever you think is right.

[zlei]

Fix a bug on Darwin that crashes clang when CLANG_DEFAULT_RTLIB=libgcc

[zlei]

@Hahnfeld Your patch applied. Thanks.

[Hahnfeld]

LGTM, thanks for this work!

Can you commit the patch yourself or should I do that for you?

[zlei]

@Hahnfeld Could you please commit it? I don't have the access.

Thanks :)

CMakeLists.txt

set(DEFAULT_SYSROOT "" CACHE PATH
   "Default <path> to all compiler invocations for --sysroot=<path>." )
 
 set(ENABLE_LINKER_BUILD_ID OFF CACHE BOOL "pass --build-id to ld")
 
 set(ENABLE_X86_RELAX_RELOCATIONS OFF CACHE BOOL
     "enable x86 relax relocations by default")
 
 set(CLANG_DEFAULT_CXX_STDLIB "" CACHE STRING
-  "Default C++ stdlib to use (empty for platform default, \"libstdc++\" or \"libc++\"")
+  "Default C++ stdlib to use (\"libstdc++\" or \"libc++\", empty for platform default")
 if (NOT(CLANG_DEFAULT_CXX_STDLIB STREQUAL "" OR
         CLANG_DEFAULT_CXX_STDLIB STREQUAL "libstdc++" OR
         CLANG_DEFAULT_CXX_STDLIB STREQUAL "libc++"))
   message(WARNING "Resetting default C++ stdlib to use platform default")
-  set(CLANG_DEFAULT_CXX_STDLIB "")
+  set(CLANG_DEFAULT_CXX_STDLIB "" CACHE STRING
+    "Default C++ stdlib to use (\"libstdc++\" or \"libc++\", empty for platform default" FORCE)
+endif()
+
+set(CLANG_DEFAULT_RTLIB "" CACHE STRING
+  "Default runtime library to use (\"libgcc\" or \"compiler-rt\", empty for platform default)")
+if (NOT(CLANG_DEFAULT_RTLIB STREQUAL "" OR
+        CLANG_DEFAULT_RTLIB STREQUAL "libgcc" OR
+        CLANG_DEFAULT_RTLIB STREQUAL "compiler-rt"))
+  message(WARNING "Resetting default rtlib to use platform default")
+  set(CLANG_DEFAULT_RTLIB "" CACHE STRING
+    "Default runtime library to use (\"libgcc\" or \"compiler-rt\", empty for platform default)" FORCE)
 endif()
 
 set(CLANG_DEFAULT_OPENMP_RUNTIME "libomp" CACHE STRING
   "Default OpenMP runtime used by -fopenmp.")
 
 set(CLANG_VENDOR ${PACKAGE_VENDOR} CACHE STRING
   "Vendor-specific text for showing with version information.")
 
 if( CLANG_VENDOR )
   add_definitions( -DCLANG_VENDOR="${CLANG_VENDOR} " )
 endif()
 
 set(CLANG_REPOSITORY_STRING "" CACHE STRING
   "Vendor-specific text for showing the repository the source is taken from.")

include/clang/Config/config.h.cmake

 /* This generated file is for internal use. Do not include it from headers. */
 
 #ifdef CLANG_CONFIG_H
 #error config.h can only be included once
 #else
 #define CLANG_CONFIG_H
 
 /* Bug report URL. */
 #define BUG_REPORT_URL "${BUG_REPORT_URL}"
 
 /* Default C++ stdlib to use. */
 #define CLANG_DEFAULT_CXX_STDLIB "${CLANG_DEFAULT_CXX_STDLIB}"
 
+/* Default runtime library to use. */
+#define CLANG_DEFAULT_RTLIB "${CLANG_DEFAULT_RTLIB}"
+
 /* Default OpenMP runtime used by -fopenmp. */
 #define CLANG_DEFAULT_OPENMP_RUNTIME "${CLANG_DEFAULT_OPENMP_RUNTIME}"
 
 /* Multilib suffix for libdir. */
 #define CLANG_LIBDIR_SUFFIX "${CLANG_LIBDIR_SUFFIX}"
 
 /* Relative directory for resource files */
 #define CLANG_RESOURCE_DIR "${CLANG_RESOURCE_DIR}"

lib/Driver/ToolChain.cpp

 }
 
 void ToolChain::addClangWarningOptions(ArgStringList &CC1Args) const {}
 
 void ToolChain::addProfileRTLibs(const llvm::Triple &EffectiveTriple,
                                  const llvm::opt::ArgList &Args,
                                  llvm::opt::ArgStringList &CmdArgs) const {
   if (!needsProfileRT(Args))
     return;
 
   CmdArgs.push_back(getCompilerRTArgString(EffectiveTriple, Args, "profile"));
 }
 
 ToolChain::RuntimeLibType ToolChain::GetRuntimeLibType(
     const ArgList &Args) const {
-  if (Arg *A = Args.getLastArg(options::OPT_rtlib_EQ)) {
-    StringRef Value = A->getValue();
-    if (Value == "compiler-rt")
-      return ToolChain::RLT_CompilerRT;
-    if (Value == "libgcc")
-      return ToolChain::RLT_Libgcc;
-    getDriver().Diag(diag::err_drv_invalid_rtlib_name)
-      << A->getAsString(Args);
-  }
+  const Arg* A = Args.getLastArg(options::OPT_rtlib_EQ);
+  StringRef LibName = A ? A->getValue() : CLANG_DEFAULT_RTLIB;
+
+  // "platform" is only used in tests to override CLANG_DEFAULT_RTLIB
+  if (LibName == "compiler-rt")
+  else if (LibName == "libgcc")
+  else if (LibName == "platform")
+    return GetDefaultRuntimeLibType();
+
+  if (A)
+    getDriver().Diag(diag::err_drv_invalid_rtlib_name) << A->getAsString(Args);
 
   return GetDefaultRuntimeLibType();
 }
 
 static bool ParseCXXStdlibType(const StringRef& Name,
                                ToolChain::CXXStdlibType& Type) {
   if (Name == "libc++")
     Type = ToolChain::CST_Libcxx;

lib/Driver/ToolChains.h

 class LLVM_LIBRARY_VISIBILITY DarwinClang : public Darwin {
 public:
   DarwinClang(const Driver &D, const llvm::Triple &Triple,
               const llvm::opt::ArgList &Args);
 
   /// @name Apple ToolChain Implementation
   /// {
 
+  RuntimeLibType GetRuntimeLibType(const llvm::opt::ArgList &Args) const override;
+
   void AddLinkRuntimeLibArgs(const llvm::Triple &EffectiveTriple,
                              const llvm::opt::ArgList &Args,
                              llvm::opt::ArgStringList &CmdArgs) const override;
 
   void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs) const override;
 
   void AddCCKextLibArgs(const llvm::opt::ArgList &Args,

lib/Driver/ToolChains.cpp

void DarwinClang::AddLinkSanitizerLibArgs(const ArgList &Args,
   AddLinkRuntimeLib(
       Args, CmdArgs,
       (Twine("libclang_rt.") + Sanitizer + "_" +
        getOSLibraryNameSuffix() + "_dynamic.dylib").str(),
       /*AlwaysLink*/ true, /*IsEmbedded*/ false,
       /*AddRPath*/ true);
 }
 
+ToolChain::RuntimeLibType DarwinClang::GetRuntimeLibType(
+    const ArgList &Args) const {
+  if (Arg* A = Args.getLastArg(options::OPT_rtlib_EQ)) {
+    StringRef Value = A->getValue();
+    if (Value != "compiler-rt")
+      getDriver().Diag(diag::err_drv_unsupported_rtlib_for_platform)
+          << Value << "darwin";
+  }
+
+  return ToolChain::RLT_CompilerRT;
+}
+
 void DarwinClang::AddLinkRuntimeLibArgs(const llvm::Triple &EffectiveTriple,
                                         const ArgList &Args,
                                         ArgStringList &CmdArgs) const {
-  // Darwin only supports the compiler-rt based runtime libraries.
-  switch (GetRuntimeLibType(Args)) {
-  case ToolChain::RLT_CompilerRT:
-    break;
-  default:
-    getDriver().Diag(diag::err_drv_unsupported_rtlib_for_platform)
-        << Args.getLastArg(options::OPT_rtlib_EQ)->getValue() << "darwin";
-    return;
-  }
+  // Call once to ensure diagnostic is printed if wrong value was specified
+  GetRuntimeLibType(Args);
 
   // Darwin doesn't support real static executables, don't link any runtime
   // libraries with -static.
   if (Args.hasArg(options::OPT_static) ||
       Args.hasArg(options::OPT_fapple_kext) ||
       Args.hasArg(options::OPT_mkernel))
     return;
 

test/Driver/linux-ld.c

 // CHECK-LD-32: "{{.*}}/usr/lib/gcc/i386-unknown-linux/4.6.0{{/|\\\\}}crtbegin.o"
 // CHECK-LD-32: "-L[[SYSROOT]]/usr/lib/gcc/i386-unknown-linux/4.6.0"
 // CHECK-LD-32: "-L[[SYSROOT]]/usr/lib/gcc/i386-unknown-linux/4.6.0/../../../../i386-unknown-linux/lib"
 // CHECK-LD-32: "-L[[SYSROOT]]/usr/lib/gcc/i386-unknown-linux/4.6.0/../../.."
 // CHECK-LD-32: "-L[[SYSROOT]]/lib"
 // CHECK-LD-32: "-L[[SYSROOT]]/usr/lib"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=x86_64-unknown-linux \
+// RUN:     --target=x86_64-unknown-linux -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_linux_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-64 %s
 // CHECK-LD-64-NOT: warning:
 // CHECK-LD-64: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
 // CHECK-LD-64: "--eh-frame-hdr"
 // CHECK-LD-64: "-m" "elf_x86_64"
 // CHECK-LD-64: "-dynamic-linker"
 // CHECK-LD-64: "{{.*}}/usr/lib/gcc/x86_64-unknown-linux/4.6.0{{/|\\\\}}crtbegin.o"
 // CHECK-LD-64: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0"
 // CHECK-LD-64: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0/../../../../x86_64-unknown-linux/lib"
 // CHECK-LD-64: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0/../../.."
 // CHECK-LD-64: "-L[[SYSROOT]]/lib"
 // CHECK-LD-64: "-L[[SYSROOT]]/usr/lib"
 // CHECK-LD-64: "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
 // CHECK-LD-64: "-lc"
 // CHECK-LD-64: "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=x86_64-unknown-linux-gnux32 \
+// RUN:     --target=x86_64-unknown-linux-gnux32 -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_linux_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-X32 %s
 // CHECK-LD-X32-NOT: warning:
 // CHECK-LD-X32: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
 // CHECK-LD-X32: "--eh-frame-hdr"
 // CHECK-LD-X32: "-m" "elf32_x86_64"
 // CHECK-LD-X32: "-dynamic-linker"

 // CHECK-LD-RT-ANDROID: "--eh-frame-hdr"
 // CHECK-LD-RT-ANDROID: "-m" "armelf_linux_eabi"
 // CHECK-LD-RT-ANDROID: "-dynamic-linker"
 // CHECK-LD-RT-ANDROID: libclang_rt.builtins-arm-android.a"
 // CHECK-LD-RT-ANDROID: "-lc"
 // CHECK-LD-RT-ANDROID: libclang_rt.builtins-arm-android.a"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=x86_64-unknown-linux \
+// RUN:     --target=x86_64-unknown-linux -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_linux_tree \
 // RUN:     --rtlib=libgcc \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-GCC %s
 // CHECK-LD-GCC-NOT: warning:
 // CHECK-LD-GCC: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
 // CHECK-LD-GCC: "--eh-frame-hdr"
 // CHECK-LD-GCC: "-m" "elf_x86_64"
 // CHECK-LD-GCC: "-dynamic-linker"
 // CHECK-LD-GCC: "{{.*}}/usr/lib/gcc/x86_64-unknown-linux/4.6.0{{/|\\\\}}crtbegin.o"
 // CHECK-LD-GCC: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0"
 // CHECK-LD-GCC: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0/../../../../x86_64-unknown-linux/lib"
 // CHECK-LD-GCC: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0/../../.."
 // CHECK-LD-GCC: "-L[[SYSROOT]]/lib"
 // CHECK-LD-GCC: "-L[[SYSROOT]]/usr/lib"
 // CHECK-LD-GCC: "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
 // CHECK-LD-GCC: "-lc"
 // CHECK-LD-GCC: "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=x86_64-unknown-linux \
+// RUN:     --target=x86_64-unknown-linux -rtlib=platform \
 // RUN:     -static-libgcc \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_linux_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-64-STATIC-LIBGCC %s
 // CHECK-LD-64-STATIC-LIBGCC-NOT: warning:
 // CHECK-LD-64-STATIC-LIBGCC: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
 // CHECK-LD-64-STATIC-LIBGCC: "--eh-frame-hdr"
 // CHECK-LD-64-STATIC-LIBGCC: "-m" "elf_x86_64"
 // CHECK-LD-64-STATIC-LIBGCC: "-dynamic-linker"
 // CHECK-LD-64-STATIC-LIBGCC: "{{.*}}/usr/lib/gcc/x86_64-unknown-linux/4.6.0{{/|\\\\}}crtbegin.o"
 // CHECK-LD-64-STATIC-LIBGCC: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0"
 // CHECK-LD-64-STATIC-LIBGCC: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0/../../../../x86_64-unknown-linux/lib"
 // CHECK-LD-64-STATIC-LIBGCC: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0/../../.."
 // CHECK-LD-64-STATIC-LIBGCC: "-L[[SYSROOT]]/lib"
 // CHECK-LD-64-STATIC-LIBGCC: "-L[[SYSROOT]]/usr/lib"
 // CHECK-LD-64-STATIC-LIBGCC: "-lgcc" "-lgcc_eh"
 // CHECK-LD-64-STATIC-LIBGCC: "-lc"
 // CHECK-LD-64-STATIC-LIBGCC: "-lgcc" "-lgcc_eh"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=x86_64-unknown-linux \
+// RUN:     --target=x86_64-unknown-linux -rtlib=platform \
 // RUN:     -static \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_linux_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-64-STATIC %s
 // CHECK-LD-64-STATIC-NOT: warning:
 // CHECK-LD-64-STATIC: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
 // CHECK-LD-64-STATIC-NOT: "--eh-frame-hdr"
 // CHECK-LD-64-STATIC: "-m" "elf_x86_64"
 // CHECK-LD-64-STATIC-NOT: "-dynamic-linker"
 // CHECK-LD-64-STATIC: "-static"
 // CHECK-LD-64-STATIC: "{{.*}}/usr/lib/gcc/x86_64-unknown-linux/4.6.0{{/|\\\\}}crtbeginT.o"
 // CHECK-LD-64-STATIC: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0"
 // CHECK-LD-64-STATIC: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0/../../../../x86_64-unknown-linux/lib"
 // CHECK-LD-64-STATIC: "-L[[SYSROOT]]/usr/lib/gcc/x86_64-unknown-linux/4.6.0/../../.."
 // CHECK-LD-64-STATIC: "-L[[SYSROOT]]/lib"
 // CHECK-LD-64-STATIC: "-L[[SYSROOT]]/usr/lib"
 // CHECK-LD-64-STATIC: "--start-group" "-lgcc" "-lgcc_eh" "-lc" "--end-group"
 //
 // Check that flags can be combined. The -static dominates.
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=x86_64-unknown-linux \
+// RUN:     --target=x86_64-unknown-linux -rtlib=platform \
 // RUN:     -static-libgcc -static \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_linux_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-64-STATIC %s
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     --target=i386-unknown-linux -m32 \
 // RUN:     --gcc-toolchain="" \

 // CHECK-DEBIAN-SPARC64: "-L[[SYSROOT]]/usr/lib/gcc/sparc64-linux-gnu/4.9/../../.."
 // CHECK-DEBIAN-SPARC64: "-L[[SYSROOT]]/lib"
 // CHECK-DEBIAN-SPARC64: "-L[[SYSROOT]]/usr/lib"
 // CHECK-DEBIAN-SPARC64: "[[SYSROOT]]/usr/lib/gcc/sparc64-linux-gnu/4.9{{/|\\\\}}crtend.o"
 // CHECK-DEBIAN-SPARC64: "[[SYSROOT]]/usr/lib/gcc/sparc64-linux-gnu/4.9/../../../sparc64-linux-gnu{{/|\\\\}}crtn.o"
 //
 // Test linker invocation on Android.
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm-linux-androideabi \
+// RUN:     --target=arm-linux-androideabi -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm-linux-android \
+// RUN:     --target=arm-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=aarch64-linux-android \
+// RUN:     --target=aarch64-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm64-linux-android \
+// RUN:     --target=arm64-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mipsel-linux-android \
+// RUN:     --target=mipsel-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mips64el-linux-android \
+// RUN:     --target=mips64el-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=i686-linux-android \
+// RUN:     --target=i686-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=x86_64-linux-android \
+// RUN:     --target=x86_64-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID %s
 // CHECK-ANDROID: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
 // CHECK-ANDROID: "{{.*}}{{/|\\\\}}crtbegin_dynamic.o"
 // CHECK-ANDROID: "-L[[SYSROOT]]/usr/lib"
 // CHECK-ANDROID-NOT: "gcc_s"
 // CHECK-ANDROID: "-lgcc"
 // CHECK-ANDROID: "-ldl"
 // CHECK-ANDROID-NOT: "gcc_s"
 // CHECK-ANDROID: "{{.*}}{{/|\\\\}}crtend_android.o"
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm-linux-androideabi \
+// RUN:     --target=arm-linux-androideabi -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -shared \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-SO %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm-linux-android \
+// RUN:     --target=arm-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -shared \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-SO %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=aarch64-linux-android \
+// RUN:     --target=aarch64-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -shared \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-SO %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm64-linux-android \
+// RUN:     --target=arm64-linux-android -rtlib=platform \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -shared \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-SO %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mipsel-linux-android \
+// RUN:     --target=mipsel-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -shared \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-SO %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mips64el-linux-android \
+// RUN:     --target=mips64el-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -shared \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-SO %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=i686-linux-android \
+// RUN:     --target=i686-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -shared \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-SO %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=x86_64-linux-android \
+// RUN:     --target=x86_64-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -shared \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-SO %s
 // CHECK-ANDROID-SO: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
 // CHECK-ANDROID-SO-NOT: "-Bsymbolic"
 // CHECK-ANDROID-SO: "{{.*}}{{/|\\\\}}crtbegin_so.o"
 // CHECK-ANDROID-SO: "-L[[SYSROOT]]/usr/lib"
 // CHECK-ANDROID-SO-NOT: "gcc_s"
 // CHECK-ANDROID-SO: "-lgcc"
 // CHECK-ANDROID-SO: "-ldl"
 // CHECK-ANDROID-SO-NOT: "gcc_s"
 // CHECK-ANDROID-SO: "{{.*}}{{/|\\\\}}crtend_so.o"
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm-linux-androideabi \
+// RUN:     --target=arm-linux-androideabi -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -static \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-STATIC %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm-linux-android \
+// RUN:     --target=arm-linux-android -rtlib=platform \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -static \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-STATIC %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=aarch64-linux-android \
+// RUN:     --target=aarch64-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -static \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-STATIC %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm64-linux-android \
+// RUN:     --target=arm64-linux-android -rtlib=platform \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -static \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-STATIC %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mipsel-linux-android \
+// RUN:     --target=mipsel-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -static \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-STATIC %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mips64el-linux-android \
+// RUN:     --target=mips64el-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -static \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-STATIC %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=i686-linux-android \
+// RUN:     --target=i686-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -static \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-STATIC %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=x86_64-linux-android \
+// RUN:     --target=x86_64-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -static \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-STATIC %s
 // CHECK-ANDROID-STATIC: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
 // CHECK-ANDROID-STATIC: "{{.*}}{{/|\\\\}}crtbegin_static.o"
 // CHECK-ANDROID-STATIC: "-L[[SYSROOT]]/usr/lib"
 // CHECK-ANDROID-STATIC-NOT: "gcc_s"
 // CHECK-ANDROID-STATIC: "-lgcc"
 // CHECK-ANDROID-STATIC-NOT: "-ldl"
 // CHECK-ANDROID-STATIC-NOT: "gcc_s"
 // CHECK-ANDROID-STATIC: "{{.*}}{{/|\\\\}}crtend_android.o"
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm-linux-androideabi \
+// RUN:     --target=arm-linux-androideabi -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot  \
 // RUN:     -pie \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-PIE %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm-linux-android \
+// RUN:     --target=arm-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -pie \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-PIE %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=aarch64-linux-android \
+// RUN:     --target=aarch64-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot  \
 // RUN:     -pie \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-PIE %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=arm64-linux-android \
+// RUN:     --target=arm64-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot  \
 // RUN:     -pie \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-PIE %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mipsel-linux-android \
+// RUN:     --target=mipsel-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -pie \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-PIE %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mips64el-linux-android \
+// RUN:     --target=mips64el-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -pie \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-PIE %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=i686-linux-android \
+// RUN:     --target=i686-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -pie \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-PIE %s
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=x86_64-linux-android \
+// RUN:     --target=x86_64-linux-android -rtlib=platform \
 // RUN:     --gcc-toolchain="" \
 // RUN:     --sysroot=%S/Inputs/basic_android_tree/sysroot \
 // RUN:     -pie \
 // RUN:   | FileCheck --check-prefix=CHECK-ANDROID-PIE %s
 // CHECK-ANDROID-PIE: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
 // CHECK-ANDROID-PIE: "{{.*}}{{/|\\\\}}crtbegin_dynamic.o"
 // CHECK-ANDROID-PIE: "-L[[SYSROOT]]/usr/lib"
 // CHECK-ANDROID-PIE-NOT: "gcc_s"

test/Driver/miamcu-opt.c

 // REQUIRES: clang-driver
 // REQUIRES: x86-registered-target
 //
-// RUN: %clang -miamcu -no-canonical-prefixes %s -### -o %t.o 2>&1 | FileCheck %s
-// RUN: %clang -miamcu -no-canonical-prefixes -m32 %s -### -o %t.o 2>&1 | FileCheck %s
-// RUN: %clang -miamcu -no-canonical-prefixes -target x86_64-unknown-linux-gnu %s -### -o %t.o 2>&1 | FileCheck %s
-// RUN: %clang -mno-iamcu -miamcu -no-canonical-prefixes %s -### -o %t.o 2>&1 | FileCheck %s
-// RUN: %clang -miamcu -no-canonical-prefixes -m64 %s -### -o %t.o 2>&1 | FileCheck %s -check-prefix=M64
-// RUN: %clang -miamcu -no-canonical-prefixes -dynamic %s -### -o %t.o 2>&1 | FileCheck %s -check-prefix=DYNAMIC
-// RUN: %clang -miamcu -no-canonical-prefixes  -target armv8-eabi %s -### -o %t.o 2>&1 | FileCheck %s -check-prefix=NOT-X86
+// RUN: %clang -miamcu -rtlib=platform -no-canonical-prefixes %s -### -o %t.o 2>&1 | FileCheck %s
+// RUN: %clang -miamcu -rtlib=platform -no-canonical-prefixes -m32 %s -### -o %t.o 2>&1 | FileCheck %s
+// RUN: %clang -miamcu -rtlib=platform -no-canonical-prefixes -target x86_64-unknown-linux-gnu %s -### -o %t.o 2>&1 | FileCheck %s
+// RUN: %clang -mno-iamcu -miamcu -rtlib=platform -no-canonical-prefixes %s -### -o %t.o 2>&1 | FileCheck %s
+// RUN: %clang -miamcu -rtlib=platform -no-canonical-prefixes -m64 %s -### -o %t.o 2>&1 | FileCheck %s -check-prefix=M64
+// RUN: %clang -miamcu -rtlib=platform -no-canonical-prefixes -dynamic %s -### -o %t.o 2>&1 | FileCheck %s -check-prefix=DYNAMIC
+// RUN: %clang -miamcu -rtlib=platform -no-canonical-prefixes  -target armv8-eabi %s -### -o %t.o 2>&1 | FileCheck %s -check-prefix=NOT-X86
 // RUN: %clang -miamcu -mno-iamcu -no-canonical-prefixes -target x86_64-unknown-linux-gnu %s -### -o %t.o 2>&1 | FileCheck %s -check-prefix=MNOIAMCU
 
 // M64: error: invalid argument '-miamcu' not allowed with '-m64'
 
 // DYNAMIC: error: invalid argument '-dynamic' not allowed with '-static'
 
 // NOT-X86: error: unsupported option '-miamcu' for target 'armv8---eabi'
 

test/Driver/miamcu-opt.cpp

-// RUN: %clang -miamcu %s -### -o %t.o 2>&1 | FileCheck %s
+// RUN: %clang -miamcu -rtlib=platform %s -### -o %t.o 2>&1 | FileCheck %s
 
 // CHECK: error: the clang compiler does not support 'C++ for IAMCU'

test/Driver/mingw-libgcc.c

 // Test if mingw toolchain driver emits static linking (-lgcc -lgcc_eh) or dynamic linking (-lgcc_s -lgcc).
 // Verified with gcc version 5.1.0 (i686-posix-dwarf-rev0, Built by MinGW-W64 project).
 
 // gcc, static
-// RUN: %clang -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
-// RUN: %clang -static -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
-// RUN: %clang -static-libgcc -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
-// RUN: %clang -static -shared -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
-// RUN: %clang -static-libgcc -shared -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static-libgcc -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static -shared -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static-libgcc -shared -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
 
 // gcc, dynamic
-// RUN: %clang -shared -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_DYNAMIC %s
+// RUN: %clang -shared -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_DYNAMIC %s
 
 // g++, static
-// RUN: %clang -static --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
-// RUN: %clang -static-libgcc --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
-// RUN: %clang -static -shared --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
-// RUN: %clang -static-libgcc -shared --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static --driver-mode=g++ -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static-libgcc --driver-mode=g++ -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static -shared --driver-mode=g++ -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
+// RUN: %clang -static-libgcc -shared --driver-mode=g++ -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_STATIC %s
 
 // g++, dynamic
-// RUN: %clang --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_DYNAMIC %s
-// RUN: %clang -shared --driver-mode=g++ -v -target i686-pc-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_DYNAMIC %s
+// RUN: %clang --driver-mode=g++ -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_DYNAMIC %s
+// RUN: %clang -shared --driver-mode=g++ -v -target i686-pc-windows-gnu -rtlib=platform -### %s 2>&1 | FileCheck -check-prefix=CHECK_DYNAMIC %s
 
 // CHECK_STATIC: "-lgcc" "-lgcc_eh"
 // CHECK_DYNAMIC: "-lgcc_s" "-lgcc"

test/Driver/mingw.cpp

-// RUN: %clang -target i686-windows-gnu -c -### --sysroot=%S/Inputs/mingw_clang_tree/mingw32 %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_CLANG_TREE %s
+// RUN: %clang -target i686-windows-gnu -rtlib=platform -c -### --sysroot=%S/Inputs/mingw_clang_tree/mingw32 %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_CLANG_TREE %s
 // CHECK_MINGW_CLANG_TREE: "{{.*}}/Inputs/mingw_clang_tree/mingw32{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}include"
 // CHECK_MINGW_CLANG_TREE: "{{.*}}/Inputs/mingw_clang_tree/mingw32{{/|\\\\}}include"
 
 
-// RUN: %clang -target i686-pc-windows-gnu -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_mingw_org_tree/mingw %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_ORG_TREE %s
+// RUN: %clang -target i686-pc-windows-gnu -rtlib=platform -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_mingw_org_tree/mingw %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_ORG_TREE %s
 // CHECK_MINGW_ORG_TREE: "{{.*}}/Inputs/mingw_mingw_org_tree/mingw{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}mingw32{{/|\\\\}}4.8.1{{/|\\\\}}include{{/|\\\\}}c++"
 // CHECK_MINGW_ORG_TREE: "{{.*}}/Inputs/mingw_mingw_org_tree/mingw{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}mingw32{{/|\\\\}}4.8.1{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}mingw32"
 // CHECK_MINGW_ORG_TREE: "{{.*}}{{/|\\\\}}Inputs/mingw_mingw_org_tree/mingw{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}mingw32{{/|\\\\}}4.8.1{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}backward"
 // CHECK_MINGW_ORG_TREE: "{{.*}}/Inputs/mingw_mingw_org_tree/mingw{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}mingw32{{/|\\\\}}4.8.1{{/|\\\\}}include"
 // CHECK_MINGW_ORG_TREE: "{{.*}}/Inputs/mingw_mingw_org_tree/mingw{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}mingw32{{/|\\\\}}4.8.1{{/|\\\\}}include-fixed"
 // CHECK_MINGW_ORG_TREE: "{{.*}}/Inputs/mingw_mingw_org_tree/mingw{{/|\\\\}}mingw32{{/|\\\\}}include"
 // CHECK_MINGW_ORG_TREE: {{.*}}/Inputs/mingw_mingw_org_tree/mingw{{/|\\\\}}include
 
 
-// RUN: %clang -target i686-pc-windows-gnu -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_mingw_builds_tree/mingw32 %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_BUILDS_TREE %s
+// RUN: %clang -target i686-pc-windows-gnu -rtlib=platform -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_mingw_builds_tree/mingw32 %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_BUILDS_TREE %s
 // CHECK_MINGW_BUILDS_TREE: "{{.*}}/Inputs/mingw_mingw_builds_tree/mingw32{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}include{{/|\\\\}}c++"
 // CHECK_MINGW_BUILDS_TREE: "{{.*}}/Inputs/mingw_mingw_builds_tree/mingw32{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}i686-w64-mingw32"
 // CHECK_MINGW_BUILDS_TREE: "{{.*}}/Inputs/mingw_mingw_builds_tree/mingw32{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}backward"
 // CHECK_MINGW_BUILDS_TREE: "{{.*}}/Inputs/mingw_mingw_builds_tree/mingw32{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}4.9.1{{/|\\\\}}include"
 // CHECK_MINGW_BUILDS_TREE: "{{.*}}/Inputs/mingw_mingw_builds_tree/mingw32{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}4.9.1{{/|\\\\}}include-fixed"
 // CHECK_MINGW_BUILDS_TREE: "{{.*}}/Inputs/mingw_mingw_builds_tree/mingw32{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}include"
 
 
-// RUN: %clang -target i686-pc-windows-gnu -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_msys2_tree/msys64/mingw32 %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_MSYS_TREE %s
+// RUN: %clang -target i686-pc-windows-gnu -rtlib=platform -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_msys2_tree/msys64/mingw32 %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_MSYS_TREE %s
 // CHECK_MINGW_MSYS_TREE: "{{.*}}/Inputs/mingw_msys2_tree/msys64{{/|\\\\}}mingw32{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}4.9.2"
 // CHECK_MINGW_MSYS_TREE: "{{.*}}/Inputs/mingw_msys2_tree/msys64/mingw32{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}4.9.2{{/|\\\\}}i686-w64-mingw32"
 // CHECK_MINGW_MSYS_TREE: "{{.*}}/Inputs/mingw_msys2_tree/msys64/mingw32{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}4.9.2{{/|\\\\}}backward"
 // CHECK_MINGW_MSYS_TREE:  "{{.*}}/Inputs/mingw_msys2_tree/msys64/mingw32{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}4.9.2{{/|\\\\}}include"
 // CHECK_MINGW_MSYS_TREE:  "{{.*}}/Inputs/mingw_msys2_tree/msys64/mingw32{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}4.9.2{{/|\\\\}}include-fixed"
 // CHECK_MINGW_MSYS_TREE: "{{.*}}/Inputs/mingw_msys2_tree/msys64/mingw32{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}include"
 // CHECK_MINGW_MSYS_TREE: "{{.*}}/Inputs/mingw_msys2_tree/msys64/mingw32{{/|\\\\}}include"
 
 
-// RUN: %clang -target x86_64-pc-windows-gnu -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_opensuse_tree/usr %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_OPENSUSE_TREE %s
+// RUN: %clang -target x86_64-pc-windows-gnu -rtlib=platform -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_opensuse_tree/usr %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_OPENSUSE_TREE %s
 // CHECK_MINGW_OPENSUSE_TREE: "{{.*}}/Inputs/mingw_opensuse_tree/usr{{/|\\\\}}lib64{{/|\\\\}}gcc{{/|\\\\}}x86_64-w64-mingw32{{/|\\\\}}5.1.0{{/|\\\\}}include{{/|\\\\}}c++"
 // CHECK_MINGW_OPENSUSE_TREE: "{{.*}}/Inputs/mingw_opensuse_tree/usr{{/|\\\\}}lib64{{/|\\\\}}gcc{{/|\\\\}}x86_64-w64-mingw32{{/|\\\\}}5.1.0{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}x86_64-w64-mingw32"
 // CHECK_MINGW_OPENSUSE_TREE: "{{.*}}/Inputs/mingw_opensuse_tree/usr{{/|\\\\}}lib64{{/|\\\\}}gcc{{/|\\\\}}x86_64-w64-mingw32{{/|\\\\}}5.1.0{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}backward"
 // CHECK_MINGW_OPENSUSE_TREE: "{{.*}}/Inputs/mingw_opensuse_tree/usr{{/|\\\\}}lib64{{/|\\\\}}gcc{{/|\\\\}}x86_64-w64-mingw32{{/|\\\\}}5.1.0{{/|\\\\}}include"
 // CHECK_MINGW_OPENSUSE_TREE: "{{.*}}/Inputs/mingw_opensuse_tree/usr{{/|\\\\}}x86_64-w64-mingw32/sys-root/mingw/include"
 // CHECK_MINGW_OPENSUSE_TREE: "{{.*}}/Inputs/mingw_opensuse_tree/usr{{/|\\\\}}lib64{{/|\\\\}}gcc{{/|\\\\}}x86_64-w64-mingw32{{/|\\\\}}5.1.0{{/|\\\\}}include-fixed"
 
 
-// RUN: %clang -target i686-pc-windows-gnu -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_arch_tree/usr %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_ARCH_TREE %s
+// RUN: %clang -target i686-pc-windows-gnu -rtlib=platform -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_arch_tree/usr %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_ARCH_TREE %s
 // CHECK_MINGW_ARCH_TREE: "{{.*}}/Inputs/mingw_arch_tree/usr{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}5.1.0"
 // CHECK_MINGW_ARCH_TREE: "{{.*}}/Inputs/mingw_arch_tree/usr{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}5.1.0{{/|\\\\}}i686-w64-mingw32"
 // CHECK_MINGW_ARCH_TREE: "{{.*}}/Inputs/mingw_arch_tree/usr{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}5.1.0{{/|\\\\}}backward"
 // CHECK_MINGW_ARCH_TREE: "{{.*}}/Inputs/mingw_arch_tree/usr{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}5.1.0{{/|\\\\}}include"
 // CHECK_MINGW_ARCH_TREE: "{{.*}}/Inputs/mingw_arch_tree/usr{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}5.1.0{{/|\\\\}}include-fixed"
 // CHECK_MINGW_ARCH_TREE: "{{.*}}/Inputs/mingw_arch_tree/usr{{/|\\\\}}i686-w64-mingw32{{/|\\\\}}include"
 
 
-// RUN: %clang -target x86_64-pc-windows-gnu -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_ubuntu_tree/usr %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_UBUNTU_TREE %s
+// RUN: %clang -target x86_64-pc-windows-gnu -rtlib=platform -stdlib=libstdc++ -c -### --sysroot=%S/Inputs/mingw_ubuntu_tree/usr %s 2>&1 | FileCheck -check-prefix=CHECK_MINGW_UBUNTU_TREE %s
 // CHECK_MINGW_UBUNTU_TREE: "{{.*}}/Inputs/mingw_ubuntu_tree/usr{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}4.8"
 // CHECK_MINGW_UBUNTU_TREE: "{{.*}}/Inputs/mingw_ubuntu_tree/usr{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}4.8{{/|\\\\}}x86_64-w64-mingw32"
 // CHECK_MINGW_UBUNTU_TREE: "{{.*}}/Inputs/mingw_ubuntu_tree/usr{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}4.8{{/|\\\\}}backward"
 // CHECK_MINGW_UBUNTU_TREE: "{{.*}}/Inputs/mingw_ubuntu_tree/usr{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}x86_64-w64-mingw32{{/|\\\\}}4.8{{/|\\\\}}include"
 // CHECK_MINGW_UBUNTU_TREE: "{{.*}}/Inputs/mingw_ubuntu_tree/usr{{/|\\\\}}lib{{/|\\\\}}gcc{{/|\\\\}}x86_64-w64-mingw32{{/|\\\\}}4.8{{/|\\\\}}include-fixed"
 // CHECK_MINGW_UBUNTU_TREE: "{{.*}}/Inputs/mingw_ubuntu_tree/usr{{/|\\\\}}x86_64-w64-mingw32{{/|\\\\}}include"

test/Driver/mips-mti-linux.c

 // Check frontend and linker invocations on GPL-free MIPS toolchain.
 //
 // FIXME: Using --sysroot with this toolchain/triple isn't supported. We use
 //        it here to test that we are producing the correct paths/flags.
 //        Ideally, we'd like to have an --llvm-toolchain option similar to
 //        the --gcc-toolchain one.
 // REQUIRES: mips-registered-target
 
 // = Big-endian, mips32r2, hard float
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mips-mti-linux -mips32r2 -mhard-float \
+// RUN:     --target=mips-mti-linux -mips32r2 -mhard-float -rtlib=platform \
 // RUN:     --sysroot=%S/Inputs/mips_mti_linux/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-BE-HF-32R2 %s
 //
 // CHECK-BE-HF-32R2: "{{[^"]*}}clang{{[^"]*}}" {{.*}} "-triple" "mips-mti-linux"
 // CHECK-BE-HF-32R2-SAME: "-fuse-init-array" "-target-cpu" "mips32r2"
 // CHECK-BE-HF-32R2-SAME: "-isysroot" "{{.*}}mips_mti_linux/sysroot"
 // CHECK-BE-HF-32R2: "{{[^"]*}}lld{{[^"]*}}" "-flavor" "old-gnu" "-target" "mips-mti-linux"
 // CHECK-BE-HF-32R2-SAME: "--sysroot=[[SYSROOT:[^"]+]]" {{.*}} "-dynamic-linker" "/lib/ld-musl-mips.so.1"
 // CHECK-BE-HF-32R2-SAME: "[[SYSROOT]]/mips-r2-hard-musl/usr/lib{{/|\\\\}}crt1.o"
 // CHECK-BE-HF-32R2-SAME: "[[SYSROOT]]/mips-r2-hard-musl/usr/lib{{/|\\\\}}crti.o"
 // CHECK-BE-HF-32R2-SAME: "-L[[SYSROOT]]/mips-r2-hard-musl/usr/lib"
 // CHECK-BE-HF-32R2-SAME: "{{[^"]+}}/mips-r2-hard-musl{{/|\\\\}}lib{{/|\\\\}}linux{{/|\\\\}}libclang_rt.builtins-mips.a"
 // CHECK-BE-HF-32R2-SAME: "-lc"
 // CHECK-BE-HF-32R2-SAME: "[[SYSROOT]]/mips-r2-hard-musl/usr/lib{{/|\\\\}}crtn.o"
 
 // = Little-endian, mips32r2, hard float
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     --target=mips-mti-linux -mips32r2 -EL -mhard-float \
+// RUN:     --target=mips-mti-linux -mips32r2 -EL -mhard-float -rtlib=platform \
 // RUN:     --sysroot=%S/Inputs/mips_mti_linux/sysroot \
 // RUN:   | FileCheck --check-prefix=CHECK-LE-HF-32R2 %s
 //
 // CHECK-LE-HF-32R2: "{{[^"]*}}clang{{[^"]*}}" {{.*}} "-triple" "mipsel-mti-linux"
 // CHECK-LE-HF-32R2-SAME: "-fuse-init-array" "-target-cpu" "mips32r2"
 // CHECK-LE-HF-32R2-SAME: "-isysroot" "{{.*}}mips_mti_linux/sysroot"
 // CHECK-LE-HF-32R2: "{{[^"]*}}lld{{[^"]*}}" "-flavor" "old-gnu" "-target" "mipsel-mti-linux"
 // CHECK-LE-HF-32R2-SAME: "--sysroot=[[SYSROOT:[^"]+]]" {{.*}} "-dynamic-linker" "/lib/ld-musl-mipsel.so.1"
 // CHECK-LE-HF-32R2-SAME: "[[SYSROOT]]/mipsel-r2-hard-musl/usr/lib{{/|\\\\}}crt1.o"
 // CHECK-LE-HF-32R2-SAME: "[[SYSROOT]]/mipsel-r2-hard-musl/usr/lib{{/|\\\\}}crti.o"
 // CHECK-LE-HF-32R2-SAME: "-L[[SYSROOT]]/mipsel-r2-hard-musl/usr/lib"
 // CHECK-LE-HF-32R2-SAME: "{{[^"]+}}/mipsel-r2-hard-musl{{/|\\\\}}lib{{/|\\\\}}linux{{/|\\\\}}libclang_rt.builtins-mips.a"
 // CHECK-LE-HF-32R2-SAME: "-lc"
 // CHECK-LE-HF-32R2-SAME: "[[SYSROOT]]/mipsel-r2-hard-musl/usr/lib{{/|\\\\}}crtn.o"

test/Driver/sanitizer-ld.c

 // RUN:   | FileCheck --check-prefix=CHECK-COV-LINUX %s
 // CHECK-COV-LINUX: "{{.*}}ld{{(.exe)?}}"
 // CHECK-COV-LINUX: "-whole-archive" "{{.*}}libclang_rt.ubsan_standalone-x86_64.a" "-no-whole-archive"
 // CHECK-COV-LINUX-NOT: "-lstdc++"
 // CHECK-COV-LINUX: "-lpthread"
 
 // CFI by itself does not link runtime libraries.
 // RUN: %clang -fsanitize=cfi %s -### -o %t.o 2>&1 \
-// RUN:     -target x86_64-unknown-linux \
+// RUN:     -target x86_64-unknown-linux -rtlib=platform \
 // RUN:     --sysroot=%S/Inputs/basic_linux_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-CFI-LINUX %s
 // CHECK-CFI-LINUX: "{{.*}}ld{{(.exe)?}}"
 // CHECK-CFI-LINUX-NOT: libclang_rt.
 
 // CFI with diagnostics links the UBSan runtime.
 // RUN: %clang -fsanitize=cfi -fno-sanitize-trap=cfi -fsanitize-recover=cfi \
 // RUN:     %s -### -o %t.o 2>&1\

test/Driver/windows-cross.c

-// RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -stdlib=libstdc++ -o /dev/null %s 2>&1 \
+// RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -stdlib=libstdc++ -rtlib=platform -o /dev/null %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-BASIC
 
 // CHECK-BASIC: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{.*}}/Inputs/Windows/ARM/8.1/usr/lib/crtbegin.obj" "-L{{.*}}/Inputs/Windows/ARM/8.1/usr/lib" "-L{{.*}}/Inputs/Windows/ARM/8.1/usr/lib/gcc" "{{.*}}.o" "-lmsvcrt" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed"
 
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %s/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -rtlib=compiler-rt -stdlib=libstdc++ -o /dev/null %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-RTLIB
 
 // CHECK-RTLIB: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{.*}}/Inputs/Windows/ARM/8.1/usr/lib/crtbegin.obj" "-L{{.*}}/Inputs/Windows/ARM/8.1/usr/lib" "-L{{.*}}/Inputs/Windows/ARM/8.1/usr/lib/gcc" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"

test/OpenMP/linking.c

 // Test the that the driver produces reasonable linker invocations with
 // -fopenmp or -fopenmp|libgomp.
 //
 // FIXME: Replace DEFAULT_OPENMP_LIB below with the value chosen at configure time.
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     -fopenmp -target i386-unknown-linux \
+// RUN:     -fopenmp -target i386-unknown-linux -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-32 %s
 // CHECK-LD-32: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-32: "-l[[DEFAULT_OPENMP_LIB:[^"]*]]" "-lgcc"
 // CHECK-LD-32: "-lpthread" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     -fopenmp -target x86_64-unknown-linux \
+// RUN:     -fopenmp -target x86_64-unknown-linux -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-64 %s
 // CHECK-LD-64: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-64: "-l[[DEFAULT_OPENMP_LIB:[^"]*]]" "-lgcc"
 // CHECK-LD-64: "-lpthread" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     -fopenmp=libgomp -target i386-unknown-linux \
+// RUN:     -fopenmp=libgomp -target i386-unknown-linux -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-GOMP-LD-32 %s
 // CHECK-GOMP-LD-32: "{{.*}}ld{{(.exe)?}}"
 // CHECK-GOMP-LD-32: "-lgomp" "-lrt" "-lgcc"
 // CHECK-GOMP-LD-32: "-lpthread" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     -fopenmp=libgomp -target x86_64-unknown-linux \
+// RUN:     -fopenmp=libgomp -target x86_64-unknown-linux -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-GOMP-LD-64 %s
 // CHECK-GOMP-LD-64: "{{.*}}ld{{(.exe)?}}"
 // CHECK-GOMP-LD-64: "-lgomp" "-lrt" "-lgcc"
 // CHECK-GOMP-LD-64: "-lpthread" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     -fopenmp -target i386-unknown-linux \
+// RUN:     -fopenmp -target i386-unknown-linux -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-IOMP5-LD-32 %s
 // CHECK-IOMP5-LD-32: "{{.*}}ld{{(.exe)?}}"
 // CHECK-IOMP5-LD-32: "-l[[DEFAULT_OPENMP_LIB:[^"]*]]" "-lgcc"
 // CHECK-IOMP5-LD-32: "-lpthread" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     -fopenmp -target x86_64-unknown-linux \
+// RUN:     -fopenmp -target x86_64-unknown-linux -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-IOMP5-LD-64 %s
 // CHECK-IOMP5-LD-64: "{{.*}}ld{{(.exe)?}}"
 // CHECK-IOMP5-LD-64: "-l[[DEFAULT_OPENMP_LIB:[^"]*]]" "-lgcc"
 // CHECK-IOMP5-LD-64: "-lpthread" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp=lib -target i386-unknown-linux \
 // RUN:   | FileCheck --check-prefix=CHECK-LIB-LD-32 %s
 // CHECK-LIB-LD-32: error: unsupported argument 'lib' to option 'fopenmp='
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp=lib -target x86_64-unknown-linux \
 // RUN:   | FileCheck --check-prefix=CHECK-LIB-LD-64 %s
 // CHECK-LIB-LD-64: error: unsupported argument 'lib' to option 'fopenmp='
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp -fopenmp=libgomp -target i386-unknown-linux \
+// RUN:     -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-OVERRIDE-32 %s
 // CHECK-LD-OVERRIDE-32: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-OVERRIDE-32: "-lgomp" "-lrt" "-lgcc"
 // CHECK-LD-OVERRIDE-32: "-lpthread" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -fopenmp -fopenmp=libgomp -target x86_64-unknown-linux \
+// RUN:     -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-LD-OVERRIDE-64 %s
 // CHECK-LD-OVERRIDE-64: "{{.*}}ld{{(.exe)?}}"
 // CHECK-LD-OVERRIDE-64: "-lgomp" "-lrt" "-lgcc"
 // CHECK-LD-OVERRIDE-64: "-lpthread" "-lc"
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     -fopenmp=libomp -target x86_64-msvc-win32 \
+// RUN:     -fopenmp=libomp -target x86_64-msvc-win32 -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-MSVC-LINK-64 %s
 // CHECK-MSVC-LINK-64: link.exe
 // CHECK-MSVC-LINK-64-SAME: -nodefaultlib:vcomp.lib
 // CHECK-MSVC-LINK-64-SAME: -nodefaultlib:vcompd.lib
 // CHECK-MSVC-LINK-64-SAME: -libpath:{{.+}}/../lib
 // CHECK-MSVC-LINK-64-SAME: -defaultlib:libomp.lib
 //
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
-// RUN:     -fopenmp=libiomp5 -target x86_64-msvc-win32 \
+// RUN:     -fopenmp=libiomp5 -target x86_64-msvc-win32 -rtlib=platform \
 // RUN:   | FileCheck --check-prefix=CHECK-MSVC-ILINK-64 %s
 // CHECK-MSVC-ILINK-64: link.exe
 // CHECK-MSVC-ILINK-64-SAME: -nodefaultlib:vcomp.lib
 // CHECK-MSVC-ILINK-64-SAME: -nodefaultlib:vcompd.lib
 // CHECK-MSVC-ILINK-64-SAME: -libpath:{{.+}}/../lib
 // CHECK-MSVC-ILINK-64-SAME: -defaultlib:libiomp5md.lib
 //