diff --git a/clang/lib/Driver/CMakeLists.txt b/clang/lib/Driver/CMakeLists.txt
--- a/clang/lib/Driver/CMakeLists.txt
+++ b/clang/lib/Driver/CMakeLists.txt
@@ -30,6 +30,7 @@
   ToolChains/Arch/Sparc.cpp
   ToolChains/Arch/SystemZ.cpp
   ToolChains/Arch/X86.cpp
+  ToolChains/AIX.cpp
   ToolChains/Ananas.cpp
   ToolChains/AMDGPU.cpp
   ToolChains/AVR.cpp
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -8,6 +8,7 @@
 
 #include "clang/Driver/Driver.h"
 #include "InputInfo.h"
+#include "ToolChains/AIX.h"
 #include "ToolChains/AMDGPU.h"
 #include "ToolChains/AVR.h"
 #include "ToolChains/Ananas.h"
@@ -4612,6 +4613,9 @@
   auto &TC = ToolChains[Target.str()];
   if (!TC) {
     switch (Target.getOS()) {
+    case llvm::Triple::AIX:
+      TC = std::make_unique<toolchains::AIX>(*this, Target, Args);
+      break;
     case llvm::Triple::Haiku:
       TC = std::make_unique<toolchains::Haiku>(*this, Target, Args);
       break;
diff --git a/clang/lib/Driver/ToolChains/AIX.h b/clang/lib/Driver/ToolChains/AIX.h
new file mode 100644
--- /dev/null
+++ b/clang/lib/Driver/ToolChains/AIX.h
@@ -0,0 +1,63 @@
+//===--- AIX.h - AIX ToolChain Implementations ------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AIX_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AIX_H
+
+#include "clang/Driver/Tool.h"
+#include "clang/Driver/ToolChain.h"
+
+namespace clang {
+namespace driver {
+namespace tools {
+
+/// aix -- Directly call system default and linker.
+// TODO: Enable direct call to system default assembler.
+namespace aix {
+
+class LLVM_LIBRARY_VISIBILITY Linker : public Tool {
+public:
+  Linker(const ToolChain &TC) : Tool("aix::Linker", "linker", TC) {}
+
+  bool hasIntegratedCPP() const override { return false; }
+  bool isLinkJob() const override { return true; }
+
+  void ConstructJob(Compilation &C, const JobAction &JA,
+                    const InputInfo &Output, const InputInfoList &Inputs,
+                    const llvm::opt::ArgList &TCArgs,
+                    const char *LinkingOutput) const override;
+};
+
+} // end namespace aix.
+
+} // end namespace tools.
+} // end namespace driver.
+} // end namespace clang.
+
+namespace clang {
+namespace driver {
+namespace toolchains {
+
+class LLVM_LIBRARY_VISIBILITY AIX : public ToolChain {
+public:
+  AIX(const Driver &D, const llvm::Triple &Triple,
+      const llvm::opt::ArgList &Args);
+
+  bool isPICDefault() const override { return true; }
+  bool isPIEDefault() const override { return false; }
+  bool isPICDefaultForced() const override { return true; }
+
+protected:
+  Tool *buildLinker() const override;
+};
+
+} // end namespace toolchains.
+} // end namespace driver.
+} // end namespace clang.
+
+#endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_AIX_H.
diff --git a/clang/lib/Driver/ToolChains/AIX.cpp b/clang/lib/Driver/ToolChains/AIX.cpp
new file mode 100644
--- /dev/null
+++ b/clang/lib/Driver/ToolChains/AIX.cpp
@@ -0,0 +1,101 @@
+//===--- AIX.cpp - AIX ToolChain Implementations ----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "AIX.h"
+#include "Arch/PPC.h"
+#include "CommonArgs.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Options.h"
+#include "clang/Driver/SanitizerArgs.h"
+#include "llvm/Option/ArgList.h"
+
+namespace aix = clang::driver::tools::aix;
+using AIX = clang::driver::toolchains::AIX;
+
+using namespace llvm::opt;
+
+void aix::Linker::ConstructJob(Compilation &C, const JobAction &JA,
+                               const InputInfo &Output,
+                               const InputInfoList &Inputs, const ArgList &Args,
+                               const char *LinkingOutput) const {
+  const AIX &ToolChain = static_cast<const AIX &>(getToolChain());
+  ArgStringList CmdArgs;
+
+  const bool IsArch32Bit = ToolChain.getTriple().isArch32Bit();
+  const bool IsArch64Bit = ToolChain.getTriple().isArch64Bit();
+  // Only support 32 and 64 bit.
+  if (!IsArch32Bit && !IsArch64Bit)
+    llvm_unreachable("Unsupported bit width value.");
+
+  // Force static linking when "-static" is present.
+  if (Args.hasArg(options::OPT_static))
+    CmdArgs.push_back("-bnso");
+
+  // Specify linker output file.
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Invalid output.");
+  }
+
+  // Set linking mode (i.e., 32/64-bit) and the address of
+  // text and data sections based on arch bit width.
+  if (IsArch32Bit) {
+    CmdArgs.push_back("-b32");
+    CmdArgs.push_back("-bpT:0x10000000");
+    CmdArgs.push_back("-bpD:0x20000000");
+  } else {
+    // Must be 64-bit, otherwise asserted already.
+    CmdArgs.push_back("-b64");
+    CmdArgs.push_back("-bpT:0x100000000");
+    CmdArgs.push_back("-bpD:0x110000000");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib)) {
+    const char *crt0 = nullptr;
+    // Enable gprofiling when "-pg" is specified.
+    if (Args.hasArg(options::OPT_pg))
+      crt0 = IsArch32Bit ? "gcrt0.o" : "gcrt0_64.o";
+    // Enable profiling when "-p" is specified.
+    else if (Args.hasArg(options::OPT_p))
+      crt0 = IsArch32Bit ? "mcrt0.o" : "mcrt0_64.o";
+    else
+      crt0 = IsArch32Bit ? "crt0.o" : "crt0_64.o";
+
+    if (crt0)
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(crt0)));
+  }
+
+  // Specify linker input file(s).
+  AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
+
+  // Add directory to library search path.
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  ToolChain.AddFilePathLibArgs(Args, CmdArgs);
+
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
+    // Support POSIX threads if "-pthreads" or "-pthread" is present.
+    if (Args.hasArg(options::OPT_pthreads, options::OPT_pthread))
+      CmdArgs.push_back("-lpthreads");
+
+    CmdArgs.push_back("-lc");
+  }
+
+  const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
+  C.addCommand(std::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
+}
+
+/// AIX - AIX tool chain which can call ld(1) directly.
+// TODO: Enable direct call to as(1).
+AIX::AIX(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
+    : ToolChain(D, Triple, Args) {
+  getFilePaths().push_back(getDriver().SysRoot + "/usr/lib");
+}
+
+auto AIX::buildLinker() const -> Tool * { return new aix::Linker(*this); }
diff --git a/clang/test/Driver/Inputs/aix_ppc_tree/powerpc-ibm-aix7.1.0.0/dummy.a b/clang/test/Driver/Inputs/aix_ppc_tree/powerpc-ibm-aix7.1.0.0/dummy.a
new file mode 100644
diff --git a/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/crt0.o b/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/crt0.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/crt0_64.o b/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/crt0_64.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/crti.o b/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/crti.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/crti_64.o b/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/crti_64.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/gcrt0.o b/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/gcrt0.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/gcrt0_64.o b/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/gcrt0_64.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/mcrt0.o b/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/mcrt0.o
new file mode 100644
diff --git a/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/mcrt0_64.o b/clang/test/Driver/Inputs/aix_ppc_tree/usr/lib/mcrt0_64.o
new file mode 100644
diff --git a/clang/test/Driver/aix-ld.c b/clang/test/Driver/aix-ld.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Driver/aix-ld.c
@@ -0,0 +1,177 @@
+// General tests that ld invocations on AIX targets are sane. Note that we use
+// sysroot to make these tests independent of the host system.
+
+// Check powerpc-ibm-aix7.1.0.0, 32-bit.
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:         -target powerpc-ibm-aix7.1.0.0 \
+// RUN:         --sysroot %S/Inputs/aix_ppc_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD32 %s
+// CHECK-LD32-NOT: warning:
+// CHECK-LD32: {{.*}}clang{{(.exe)?}}" "-cc1" "-triple" "powerpc-ibm-aix7.1.0.0"
+// CHECK-LD32: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-LD32: "{{.*}}ld{{(.exe)?}}" 
+// CHECK-LD32-NOT: "-bnso"
+// CHECK-LD32: "-b32" 
+// CHECK-LD32: "-bpT:0x10000000" "-bpD:0x20000000" 
+// CHECK-LD32: "[[SYSROOT]]/usr/lib{{/|\\\\}}crt0.o"
+// CHECK-LD32: "-L[[SYSROOT]]/usr/lib" 
+// CHECK-LD32: "-lc"
+
+// Check powerpc64-ibm-aix7.1.0.0, 64-bit.
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:         -target powerpc64-ibm-aix7.1.0.0 \
+// RUN:         --sysroot %S/Inputs/aix_ppc_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD64 %s
+// CHECK-LD64-NOT: warning:
+// CHECK-LD64: {{.*}}clang{{(.exe)?}}" "-cc1" "-triple" "powerpc64-ibm-aix7.1.0.0"
+// CHECK-LD64: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-LD64: "{{.*}}ld{{(.exe)?}}" 
+// CHECK-LD64-NOT: "-bnso"
+// CHECK-LD64: "-b64" 
+// CHECK-LD64: "-bpT:0x100000000" "-bpD:0x110000000" 
+// CHECK-LD64: "[[SYSROOT]]/usr/lib{{/|\\\\}}crt0_64.o"
+// CHECK-LD64: "-L[[SYSROOT]]/usr/lib" 
+// CHECK-LD64: "-lc"
+
+// Check powerpc-ibm-aix7.1.0.0, 32-bit. Enable POSIX thread support.
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:         -pthread \
+// RUN:         -target powerpc-ibm-aix7.1.0.0 \
+// RUN:         --sysroot %S/Inputs/aix_ppc_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD32-PTHREAD %s
+// CHECK-LD32-PTHREAD-NOT: warning:
+// CHECK-LD32-PTHREAD: {{.*}}clang{{(.exe)?}}" "-cc1" "-triple" "powerpc-ibm-aix7.1.0.0"
+// CHECK-LD32-PTHREAD: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-LD32-PTHREAD: "{{.*}}ld{{(.exe)?}}" 
+// CHECK-LD32-PTHREAD-NOT: "-bnso"
+// CHECK-LD32-PTHREAD: "-b32" 
+// CHECK-LD32-PTHREAD: "-bpT:0x10000000" "-bpD:0x20000000" 
+// CHECK-LD32-PTHREAD: "[[SYSROOT]]/usr/lib{{/|\\\\}}crt0.o"
+// CHECK-LD32-PTHREAD: "-L[[SYSROOT]]/usr/lib"
+// CHECK-LD32-PTHREAD: "-lpthreads"
+// CHECK-LD32-PTHREAD: "-lc"
+
+// Check powerpc-ibm-aix7.1.0.0, 64-bit. POSIX thread alias.
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:         -pthreads \
+// RUN:         -target powerpc64-ibm-aix7.1.0.0 \
+// RUN:         --sysroot %S/Inputs/aix_ppc_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD64-PTHREAD %s
+// CHECK-LD64-PTHREAD-NOT: warning:
+// CHECK-LD64-PTHREAD: {{.*}}clang{{(.exe)?}}" "-cc1" "-triple" "powerpc64-ibm-aix7.1.0.0"
+// CHECK-LD64-PTHREAD: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-LD64-PTHREAD: "{{.*}}ld{{(.exe)?}}" 
+// CHECK-LD64-PTHREAD-NOT: "-bnso"
+// CHECK-LD64-PTHREAD: "-b64" 
+// CHECK-LD64-PTHREAD: "-bpT:0x100000000" "-bpD:0x110000000" 
+// CHECK-LD64-PTHREAD: "[[SYSROOT]]/usr/lib{{/|\\\\}}crt0_64.o"
+// CHECK-LD64-PTHREAD: "-L[[SYSROOT]]/usr/lib"
+// CHECK-LD64-PTHREAD: "-lpthreads"
+// CHECK-LD64-PTHREAD: "-lc"
+
+// Check powerpc-ibm-aix7.1.0.0, 32-bit. Enable profiling.
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:         -p \
+// RUN:         -target powerpc-ibm-aix7.1.0.0 \
+// RUN:         --sysroot %S/Inputs/aix_ppc_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD32-PROF %s
+// CHECK-LD32-PROF-NOT: warning:
+// CHECK-LD32-PROF: {{.*}}clang{{(.exe)?}}" "-cc1" "-triple" "powerpc-ibm-aix7.1.0.0"
+// CHECK-LD32-PROF: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-LD32-PROF: "{{.*}}ld{{(.exe)?}}" 
+// CHECK-LD32-PROF-NOT: "-bnso"
+// CHECK-LD32-PROF: "-b32" 
+// CHECK-LD32-PROF: "-bpT:0x10000000" "-bpD:0x20000000" 
+// CHECK-LD32-PROF: "[[SYSROOT]]/usr/lib{{/|\\\\}}mcrt0.o"
+// CHECK-LD32-PROF: "-L[[SYSROOT]]/usr/lib" 
+// CHECK-LD32-PROF: "-lc"
+
+// Check powerpc64-ibm-aix7.1.0.0, 64-bit. Enable g-profiling.
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:         -pg \
+// RUN:         -target powerpc64-ibm-aix7.1.0.0 \
+// RUN:         --sysroot %S/Inputs/aix_ppc_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD64-GPROF %s
+// CHECK-LD64-GPROF-NOT: warning:
+// CHECK-LD64-GPROF: {{.*}}clang{{(.exe)?}}" "-cc1" "-triple" "powerpc64-ibm-aix7.1.0.0"
+// CHECK-LD64-GPROF: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-LD64-GPROF: "{{.*}}ld{{(.exe)?}}" 
+// CHECK-LD64-GPROF-NOT: "-bnso"
+// CHECK-LD64-GPROF: "-b64" 
+// CHECK-LD64-GPROF: "-bpT:0x100000000" "-bpD:0x110000000" 
+// CHECK-LD64-GPROF: "[[SYSROOT]]/usr/lib{{/|\\\\}}gcrt0_64.o"
+// CHECK-LD64-GPROF: "-L[[SYSROOT]]/usr/lib" 
+// CHECK-LD64-GPROF: "-lc"
+
+// Check powerpc-ibm-aix7.1.0.0, 32-bit. Static linking.
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:         -static \
+// RUN:         -target powerpc-ibm-aix7.1.0.0 \
+// RUN:         --sysroot %S/Inputs/aix_ppc_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD32-STATIC %s
+// CHECK-LD32-STATIC-NOT: warning:
+// CHECK-LD32-STATIC: {{.*}}clang{{(.exe)?}}" "-cc1" "-triple" "powerpc-ibm-aix7.1.0.0"
+// CHECK-LD32-STATIC: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-LD32-STATIC: "{{.*}}ld{{(.exe)?}}" 
+// CHECK-LD32-STATIC: "-bnso"
+// CHECK-LD32-STATIC: "-b32" 
+// CHECK-LD32-STATIC: "-bpT:0x10000000" "-bpD:0x20000000" 
+// CHECK-LD32-STATIC: "[[SYSROOT]]/usr/lib{{/|\\\\}}crt0.o"
+// CHECK-LD32-STATIC: "-L[[SYSROOT]]/usr/lib" 
+// CHECK-LD32-STATIC: "-lc"
+
+// Check powerpc-ibm-aix7.1.0.0, 32-bit. Library search path.
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:         -L%S/Inputs/aix_ppc_tree/powerpc-ibm-aix7.1.0.0 \
+// RUN:         -target powerpc-ibm-aix7.1.0.0 \
+// RUN:         --sysroot %S/Inputs/aix_ppc_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD32-LIBP %s
+// CHECK-LD32-LIBP-NOT: warning:
+// CHECK-LD32-LIBP: {{.*}}clang{{(.exe)?}}" "-cc1" "-triple" "powerpc-ibm-aix7.1.0.0"
+// CHECK-LD32-LIBP: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-LD32-LIBP: "{{.*}}ld{{(.exe)?}}" 
+// CHECK-LD32-LIBP-NOT: "-bnso"
+// CHECK-LD32-LIBP: "-b32" 
+// CHECK-LD32-LIBP: "-bpT:0x10000000" "-bpD:0x20000000" 
+// CHECK-LD32-LIBP: "[[SYSROOT]]/usr/lib{{/|\\\\}}crt0.o"
+// CHECK-LD32-LIBP: "-L[[SYSROOT]]/powerpc-ibm-aix7.1.0.0" 
+// CHECK-LD32-LIBP: "-L[[SYSROOT]]/usr/lib" 
+// CHECK-LD32-LIBP: "-lc"
+
+// Check powerpc-ibm-aix7.1.0.0, 32-bit. nostdlib
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:         -nostdlib \
+// RUN:         -pthread \
+// RUN:         -target powerpc-ibm-aix7.1.0.0 \
+// RUN:         --sysroot %S/Inputs/aix_ppc_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD32-NO-STD-LIB %s
+// CHECK-LD32-NO-STD-LIB-NOT: warning:
+// CHECK-LD32-NO-STD-LIB: {{.*}}clang{{(.exe)?}}" "-cc1" "-triple" "powerpc-ibm-aix7.1.0.0"
+// CHECK-LD32-NO-STD-LIB: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-LD32-NO-STD-LIB: "{{.*}}ld{{(.exe)?}}" 
+// CHECK-LD32-NO-STD-LIB-NOT: "-bnso"
+// CHECK-LD32-NO-STD-LIB: "-b32" 
+// CHECK-LD32-NO-STD-LIB: "-bpT:0x10000000" "-bpD:0x20000000" 
+// CHECK-LD32-NO-STD-LIB-NOT: "[[SYSROOT]]/usr/lib{{/|\\\\}}crt0.o"
+// CHECK-LD32-NO-STD-LIB: "-L[[SYSROOT]]/usr/lib" 
+// CHECK-LD32-NO-STD-LIB-NOT: "-lpthreads"
+// CHECK-LD32-NO-STD-LIB-NOT: "-lc"
+
+// Check powerpc-ibm-aix7.1.0.0, 64-bit. nodefaultlibs
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:         -nodefaultlibs \
+// RUN:         -pthread \
+// RUN:         -target powerpc64-ibm-aix7.1.0.0 \
+// RUN:         --sysroot %S/Inputs/aix_ppc_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-LD64-NO-DEFAULT-LIBS %s
+// CHECK-LD64-NO-DEFAULT-LIBS-NOT: warning:
+// CHECK-LD64-NO-DEFAULT-LIBS: {{.*}}clang{{(.exe)?}}" "-cc1" "-triple" "powerpc64-ibm-aix7.1.0.0"
+// CHECK-LD64-NO-DEFAULT-LIBS: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-LD64-NO-DEFAULT-LIBS: "{{.*}}ld{{(.exe)?}}" 
+// CHECK-LD64-NO-DEFAULT-LIBS-NOT: "-bnso"
+// CHECK-LD64-NO-DEFAULT-LIBS: "-b64" 
+// CHECK-LD64-NO-DEFAULT-LIBS: "-bpT:0x100000000" "-bpD:0x110000000" 
+// CHECK-LD64-NO-DEFAULT-LIBS: "[[SYSROOT]]/usr/lib{{/|\\\\}}crt0_64.o"
+// CHECK-LD64-NO-DEFAULT-LIBS: "-L[[SYSROOT]]/usr/lib" 
+// CHECK-LD64-NO-DEFAULT-LIBS-NOT: "-lpthreads"
+// CHECK-LD64-NO-DEFAULT-LIBS-NOT: "-lc"