diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp
index eecaaa9a42930..7b0f2bc2fd389 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.cpp
+++ b/clang/lib/Driver/ToolChains/BareMetal.cpp
@@ -97,7 +97,8 @@ static bool findRISCVMultilibs(const Driver &D,
   return false;
 }
 
-static std::string computeBaseSysRoot(const Driver &D, bool IncludeTriple) {
+static std::string computeInstalledToolchainSysRoot(const Driver &D,
+                                                    bool IncludeTriple) {
   if (!D.SysRoot.empty())
     return D.SysRoot;
 
@@ -110,20 +111,93 @@ static std::string computeBaseSysRoot(const Driver &D, bool IncludeTriple) {
   return std::string(SysRootDir);
 }
 
+// GCC sysroot here means form sysroot from either --gcc-install-dir, or from
+// --gcc-toolchain or if the toolchain is installed alongside clang in
+// bin/../<TargetTriple> directory if it is not explicitly specified on the
+// command line through `--sysroot` option. libc here will be newlib.
+std::string BareMetal::computeGCCSysRoot() const {
+  if (!getDriver().SysRoot.empty())
+    return getDriver().SysRoot;
+
+  SmallString<128> SysRootDir;
+  if (GCCInstallation.isValid()) {
+    StringRef LibDir = GCCInstallation.getParentLibPath();
+    StringRef TripleStr = GCCInstallation.getTriple().str();
+    llvm::sys::path::append(SysRootDir, LibDir, "..", TripleStr);
+  } else {
+    // Use the triple as provided to the driver. Unlike the parsed triple
+    // this has not been normalized to always contain every field.
+    llvm::sys::path::append(SysRootDir, getDriver().Dir, "..",
+                            getDriver().getTargetTriple());
+  }
+
+  if (!llvm::sys::fs::exists(SysRootDir))
+    return std::string();
+
+  return std::string(SysRootDir);
+}
+
+std::string BareMetal::computeSysRoot() const {
+  if (!SysRoot.empty())
+    return SysRoot;
+
+  std::string SysRoot = getDriver().SysRoot;
+  if (!SysRoot.empty() && llvm::sys::fs::exists(SysRoot))
+    return SysRoot;
+
+  // Verify the GCC installation from -gcc-install-dir, --gcc-toolchain, or
+  // alongside clang. If valid, form the sysroot. Otherwise, check
+  // lib/clang-runtimes above the driver.
+  SysRoot = computeGCCSysRoot();
+  if (!SysRoot.empty())
+    return SysRoot;
+
+  SysRoot =
+      computeInstalledToolchainSysRoot(getDriver(), /*IncludeTriple*/ true);
+
+  return SysRoot;
+}
+
+static void addMultilibsFilePaths(const Driver &D, const MultilibSet &Multilibs,
+                                  const Multilib &Multilib,
+                                  StringRef InstallPath,
+                                  ToolChain::path_list &Paths) {
+  if (const auto &PathsCallback = Multilibs.filePathsCallback())
+    for (const auto &Path : PathsCallback(Multilib))
+      addPathIfExists(D, InstallPath + Path, Paths);
+}
+
 BareMetal::BareMetal(const Driver &D, const llvm::Triple &Triple,
                      const ArgList &Args)
-    : ToolChain(D, Triple, Args),
-      SysRoot(computeBaseSysRoot(D, /*IncludeTriple=*/true)) {
-  getProgramPaths().push_back(getDriver().Dir);
-
-  findMultilibs(D, Triple, Args);
-  SmallString<128> SysRoot(computeSysRoot());
-  if (!SysRoot.empty()) {
-    for (const Multilib &M : getOrderedMultilibs()) {
-      SmallString<128> Dir(SysRoot);
-      llvm::sys::path::append(Dir, M.osSuffix(), "lib");
-      getFilePaths().push_back(std::string(Dir));
-      getLibraryPaths().push_back(std::string(Dir));
+    : Generic_ELF(D, Triple, Args) {
+  GCCInstallation.init(Triple, Args);
+  SysRoot = computeSysRoot();
+  if (GCCInstallation.isValid()) {
+    Multilibs = GCCInstallation.getMultilibs();
+    SelectedMultilibs.assign({GCCInstallation.getMultilib()});
+    path_list &Paths = getFilePaths();
+    // Add toolchain/multilib specific file paths.
+    addMultilibsFilePaths(D, Multilibs, SelectedMultilibs.back(),
+                          GCCInstallation.getInstallPath(), Paths);
+    getFilePaths().push_back(GCCInstallation.getInstallPath().str());
+    ToolChain::path_list &PPaths = getProgramPaths();
+    // Multilib cross-compiler GCC installations put ld in a triple-prefixed
+    // directory off of the parent of the GCC installation.
+    PPaths.push_back(Twine(GCCInstallation.getParentLibPath() + "/../" +
+                           GCCInstallation.getTriple().str() + "/bin")
+                         .str());
+    PPaths.push_back((GCCInstallation.getParentLibPath() + "/../bin").str());
+    getFilePaths().push_back(computeSysRoot() + "/lib");
+  } else {
+    getProgramPaths().push_back(getDriver().Dir);
+    findMultilibs(D, Triple, Args);
+    if (!SysRoot.empty()) {
+      for (const Multilib &M : getOrderedMultilibs()) {
+        SmallString<128> Dir(SysRoot);
+        llvm::sys::path::append(Dir, M.osSuffix(), "lib");
+        getFilePaths().push_back(std::string(Dir));
+        getLibraryPaths().push_back(std::string(Dir));
+      }
     }
   }
 }
@@ -215,7 +289,7 @@ getMultilibConfigPath(const Driver &D, const llvm::Triple &Triple,
       return {};
     }
   } else {
-    MultilibPath = computeBaseSysRoot(D, /*IncludeTriple=*/false);
+    MultilibPath = computeInstalledToolchainSysRoot(D, /*IncludeTriple=*/false);
     llvm::sys::path::append(MultilibPath, MultilibFilename);
   }
   return MultilibPath;
@@ -233,7 +307,7 @@ void BareMetal::findMultilibs(const Driver &D, const llvm::Triple &Triple,
   if (D.getVFS().exists(*MultilibPath)) {
     // If multilib.yaml is found, update sysroot so it doesn't use a target
     // specific suffix
-    SysRoot = computeBaseSysRoot(D, /*IncludeTriple=*/false);
+    SysRoot = computeInstalledToolchainSysRoot(D, /*IncludeTriple=*/false);
     findMultilibsFromYAML(*this, D, *MultilibPath, Args, Result);
     SelectedMultilibs = Result.SelectedMultilibs;
     Multilibs = Result.Multilibs;
@@ -258,8 +332,6 @@ Tool *BareMetal::buildStaticLibTool() const {
   return new tools::baremetal::StaticLibTool(*this);
 }
 
-std::string BareMetal::computeSysRoot() const { return SysRoot; }
-
 BareMetal::OrderedMultilibs BareMetal::getOrderedMultilibs() const {
   // Get multilibs in reverse order because they're ordered most-specific last.
   if (!SelectedMultilibs.empty())
@@ -304,6 +376,19 @@ void BareMetal::addClangTargetOptions(const ArgList &DriverArgs,
   CC1Args.push_back("-nostdsysteminc");
 }
 
+void BareMetal::addLibStdCxxIncludePaths(
+    const llvm::opt::ArgList &DriverArgs,
+    llvm::opt::ArgStringList &CC1Args) const {
+  if (!GCCInstallation.isValid())
+    return;
+  const GCCVersion &Version = GCCInstallation.getVersion();
+  StringRef TripleStr = GCCInstallation.getTriple().str();
+  const Multilib &Multilib = GCCInstallation.getMultilib();
+  addLibStdCXXIncludePaths(computeSysRoot() + "/include/c++/" + Version.Text,
+                           TripleStr, Multilib.includeSuffix(), DriverArgs,
+                           CC1Args);
+}
+
 void BareMetal::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
                                              ArgStringList &CC1Args) const {
   if (DriverArgs.hasArg(options::OPT_nostdinc, options::OPT_nostdlibinc,
@@ -341,7 +426,7 @@ void BareMetal::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
       break;
     }
     case ToolChain::CST_Libstdcxx:
-      // We only support libc++ toolchain installation.
+      addLibStdCxxIncludePaths(DriverArgs, CC1Args);
       break;
   }
 
diff --git a/clang/lib/Driver/ToolChains/BareMetal.h b/clang/lib/Driver/ToolChains/BareMetal.h
index 483b5efab5e6e..de3b1b267c8e7 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.h
+++ b/clang/lib/Driver/ToolChains/BareMetal.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_BAREMETAL_H
 #define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_BAREMETAL_H
 
+#include "ToolChains/Gnu.h"
 #include "clang/Driver/Tool.h"
 #include "clang/Driver/ToolChain.h"
 
@@ -19,7 +20,7 @@ namespace driver {
 
 namespace toolchains {
 
-class LLVM_LIBRARY_VISIBILITY BareMetal : public ToolChain {
+class LLVM_LIBRARY_VISIBILITY BareMetal : public Generic_ELF {
 public:
   BareMetal(const Driver &D, const llvm::Triple &Triple,
             const llvm::opt::ArgList &Args);
@@ -35,7 +36,6 @@ class LLVM_LIBRARY_VISIBILITY BareMetal : public ToolChain {
   Tool *buildStaticLibTool() const override;
 
 public:
-  bool useIntegratedAs() const override { return true; }
   bool isBareMetal() const override { return true; }
   bool isCrossCompiling() const override { return true; }
   bool HasNativeLLVMSupport() const override { return true; }
@@ -67,6 +67,9 @@ class LLVM_LIBRARY_VISIBILITY BareMetal : public ToolChain {
   void AddClangCXXStdlibIncludeArgs(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
+  void
+  addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                           llvm::opt::ArgStringList &CC1Args) const override;
   std::string computeSysRoot() const override;
   SanitizerMask getSupportedSanitizers() const override;
 
@@ -76,6 +79,7 @@ class LLVM_LIBRARY_VISIBILITY BareMetal : public ToolChain {
   OrderedMultilibs getOrderedMultilibs() const;
 
   std::string SysRoot;
+  std::string computeGCCSysRoot() const;
 };
 
 } // namespace toolchains
diff --git a/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/bin/ld b/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/bin/ld
new file mode 100644
index 0000000000000..b23e55619b2ff
--- /dev/null
+++ b/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/bin/ld
@@ -0,0 +1 @@
+#!/bin/true
diff --git a/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/8.2.1/.keep b/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/8.2.1/.keep
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/.keep b/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/.keep
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/crt0.o b/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/lib/crt0.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o b/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtbegin.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o b/clang/test/Driver/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/crtend.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf/bin/ld b/clang/test/Driver/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf/bin/ld
new file mode 100644
index 0000000000000..b23e55619b2ff
--- /dev/null
+++ b/clang/test/Driver/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf/bin/ld
@@ -0,0 +1 @@
+#!/bin/true
diff --git a/clang/test/Driver/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf/lib/.keep b/clang/test/Driver/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf/lib/.keep
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf/lib/crt0.o b/clang/test/Driver/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf/lib/crt0.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf/lib/crtbegin.o b/clang/test/Driver/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf/lib/crtbegin.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf/lib/crtend.o b/clang/test/Driver/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf/lib/crtend.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/bin/ld b/clang/test/Driver/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/bin/ld
new file mode 100644
index 0000000000000..b23e55619b2ff
--- /dev/null
+++ b/clang/test/Driver/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/bin/ld
@@ -0,0 +1 @@
+#!/bin/true
diff --git a/clang/test/Driver/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include/c++/8.2.1/.keep b/clang/test/Driver/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include/c++/8.2.1/.keep
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/.keep b/clang/test/Driver/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/.keep
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/crt0.o b/clang/test/Driver/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/crt0.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/libstdc++.a b/clang/test/Driver/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/lib/libstdc++.a
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtbegin.o b/clang/test/Driver/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtbegin.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtend.o b/clang/test/Driver/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/crtend.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi/bin/ld b/clang/test/Driver/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi/bin/ld
new file mode 100644
index 0000000000000..b23e55619b2ff
--- /dev/null
+++ b/clang/test/Driver/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi/bin/ld
@@ -0,0 +1 @@
+#!/bin/true
diff --git a/clang/test/Driver/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi/lib/.keep b/clang/test/Driver/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi/lib/.keep
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi/lib/crt0.o b/clang/test/Driver/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi/lib/crt0.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi/lib/crtbegin.o b/clang/test/Driver/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi/lib/crtbegin.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi/lib/crtend.o b/clang/test/Driver/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi/lib/crtend.o
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/clang/test/Driver/aarch64-toolchain-extra.c b/clang/test/Driver/aarch64-toolchain-extra.c
new file mode 100644
index 0000000000000..c4e05fd5d1043
--- /dev/null
+++ b/clang/test/Driver/aarch64-toolchain-extra.c
@@ -0,0 +1,28 @@
+// A basic clang -cc1 command-line, and simple environment check.
+
+// The tests here are similar to those in aarch64-toolchain.c, however
+// these tests need to create symlinks to test directory trees in order to
+// set up the environment and therefore shell support is required.
+// REQUIRES: shell
+// UNSUPPORTED: system-windows
+
+// If there is no GCC install detected then the driver searches for executables
+// and runtime starting from the directory tree above the driver itself.
+// The test below checks that the driver correctly finds the linker and
+// runtime if and only if they exist.
+//
+// RUN: rm -rf %t
+// RUN: mkdir -p %t/aarch64-nogcc/bin
+// RUN: ln -s %clang %t/aarch64-nogcc/bin/clang
+// RUN: ln -s %S/Inputs/basic_aarch64_nogcc_tree/aarch64-none-elf %t/aarch64-nogcc/aarch64-none-elf
+// RUN: %t/aarch64-nogcc/bin/clang %s -### -no-canonical-prefixes \
+// RUN:    --gcc-toolchain=%t/aarch64-nogcc/invalid \
+// RUN:    --target=aarch64-none-elf --rtlib=libgcc -fuse-ld=ld 2>&1 \
+// RUN:    | FileCheck -check-prefix=C-ARM-BAREMETAL-NOGCC %s
+
+// RUN: %t/aarch64-nogcc/bin/clang %s -### -no-canonical-prefixes \
+// RUN:    --sysroot=%t/aarch64-nogcc/bin/../aarch64-none-elf \
+// RUN:    --target=aarch64-none-elf --rtlib=libgcc -fuse-ld=ld 2>&1 \
+// RUN:    | FileCheck -check-prefix=C-ARM-BAREMETAL-NOGCC %s
+
+// C-ARM-BAREMETAL-NOGCC: "-internal-isystem" "{{.*}}/aarch64-nogcc/bin/../aarch64-none-elf/include"
\ No newline at end of file
diff --git a/clang/test/Driver/aarch64-toolchain.c b/clang/test/Driver/aarch64-toolchain.c
new file mode 100644
index 0000000000000..b850e0fe8954e
--- /dev/null
+++ b/clang/test/Driver/aarch64-toolchain.c
@@ -0,0 +1,61 @@
+// UNSUPPORTED: system-windows
+
+// RUN: %clang -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf 2>&1 \
+// RUN:   | FileCheck -check-prefix=C-AARCH64-BAREMETAL %s
+
+// C-AARCH64-BAREMETAL: "-cc1" "-triple" "aarch64-unknown-none-elf"
+// C-AARCH64-BAREMETAL: "-isysroot" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf"
+// C-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include"
+
+// RUN: %clang -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=  2>&1 \
+// RUN:   | FileCheck -check-prefix=C-AARCH64-BAREMETAL-NOSYSROOT %s
+
+// C-AARCH64-BAREMETAL-NOSYSROOT: "-cc1" "-triple" "aarch64-unknown-none-elf"
+// C-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include"
+
+// RUN: %clangxx -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf -stdlib=libstdc++ --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf 2>&1 \
+// RUN:   | FileCheck -check-prefix=CXX-AARCH64-BAREMETAL %s
+
+// CXX-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/8.2.1/aarch64-none-elf"
+// CXX-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/8.2.1/backward"
+// CXX-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/8.2.1"
+// CXX-AARCH64-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include"
+
+// RUN: %clangxx -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf -stdlib=libstdc++ --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=  2>&1 \
+// RUN:   | FileCheck -check-prefix=CXX-AARCH64-BAREMETAL-NOSYSROOT %s
+
+// CXX-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include/c++/8.2.1/aarch64-none-elf"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include/c++/8.2.1/backward"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include/c++/8.2.1"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include"
+
+// RUN: %clangxx -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf -stdlib=libc++ --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf 2>&1 \
+// RUN:   | FileCheck -check-prefix=CXX-AARCH64-BAREMETAL-LIBCXX %s
+
+// CXX-AARCH64-BAREMETAL-LIBCXX: "-isysroot" "{{.*}}Inputs/basic_aarch64_gcc_tree/aarch64-none-elf"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include/c++/v1"
+// CXX-AARCH64-BAREMETAL-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/aarch64-none-elf/include"
+
+// RUN: %clangxx -### %s -fuse-ld= \
+// RUN:   --target=aarch64-none-elf -stdlib=libc++ --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_aarch64_gcc_tree \
+// RUN:   --sysroot=  2>&1 \
+// RUN:   | FileCheck -check-prefix=CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX %s
+
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include/c++/v1"
+// CXX-AARCH64-BAREMETAL-NOSYSROOT-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_aarch64_gcc_tree/lib/gcc/aarch64-none-elf/8.2.1/../../../../aarch64-none-elf/include"
\ No newline at end of file
diff --git a/clang/test/Driver/arm-gnutools.c b/clang/test/Driver/arm-gnutools.c
new file mode 100644
index 0000000000000..127e40dc74da7
--- /dev/null
+++ b/clang/test/Driver/arm-gnutools.c
@@ -0,0 +1,12 @@
+// check that gnu assembler is invoked with arm baremetal as well
+
+// RUN: %clang --target=armv6m-none-eabi  --gcc-toolchain=%S/Inputs/basic_riscv32_tree -fno-integrated-as %s -### -c \
+// RUN: 2>&1 | FileCheck %s
+
+// RUN: %clang --target=armv7-none-eabi  --gcc-toolchain=%S/Inputs/basic_riscv32_tree -fno-integrated-as %s -### -c \
+// RUN: 2>&1 | FileCheck %s
+
+// RUN: %clang --target=aarch64-none-elf  --gcc-toolchain=%S/Inputs/basic_riscv32_tree -fno-integrated-as %s -### -c \
+// RUN: 2>&1 | FileCheck %s
+
+// CHECK: "{{.*}}as{{(.exe)?}}"
\ No newline at end of file
diff --git a/clang/test/Driver/arm-toolchain-extra.c b/clang/test/Driver/arm-toolchain-extra.c
new file mode 100644
index 0000000000000..cd1b76bdb0866
--- /dev/null
+++ b/clang/test/Driver/arm-toolchain-extra.c
@@ -0,0 +1,28 @@
+// A basic clang -cc1 command-line, and simple environment check.
+
+// The tests here are similar to those in arm-toolchain.c, however
+// these tests need to create symlinks to test directory trees in order to
+// set up the environment and therefore shell support is required.
+// REQUIRES: shell
+// UNSUPPORTED: system-windows
+
+// If there is no GCC install detected then the driver searches for executables
+// and runtime starting from the directory tree above the driver itself.
+// The test below checks that the driver correctly finds the linker and
+// runtime if and only if they exist.
+//
+// RUN: rm -rf %t
+// RUN: mkdir -p %t/arm-nogcc/bin
+// RUN: ln -s %clang %t/arm-nogcc/bin/clang
+// RUN: ln -s %S/Inputs/basic_arm_nogcc_tree/armv6m-none-eabi %t/arm-nogcc/armv6m-none-eabi
+// RUN: %t/arm-nogcc/bin/clang %s -### -no-canonical-prefixes \
+// RUN:    --gcc-toolchain=%t/arm-nogcc/invalid \
+// RUN:    --target=armv6m-none-eabi --rtlib=libgcc -fuse-ld=ld 2>&1 \
+// RUN:    | FileCheck -check-prefix=C-ARM-BAREMETAL-NOGCC %s
+
+// RUN: %t/arm-nogcc/bin/clang %s -### -no-canonical-prefixes \
+// RUN:    --sysroot=%t/arm-nogcc/bin/../armv6m-none-eabi \
+// RUN:    --target=armv6m-none-eabi --rtlib=libgcc -fuse-ld=ld 2>&1 \
+// RUN:    | FileCheck -check-prefix=C-ARM-BAREMETAL-NOGCC %s
+
+// C-ARM-BAREMETAL-NOGCC: "-internal-isystem" "{{.*}}/arm-nogcc/bin/../armv6m-none-eabi/include"
diff --git a/clang/test/Driver/arm-toolchain.c b/clang/test/Driver/arm-toolchain.c
new file mode 100644
index 0000000000000..f3bde17a83c64
--- /dev/null
+++ b/clang/test/Driver/arm-toolchain.c
@@ -0,0 +1,62 @@
+// UNSUPPORTED: system-windows
+
+// RUN: %clang -### %s -fuse-ld= \
+// RUN:   --target=armv6m-none-eabi --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_arm_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_arm_gcc_tree/armv6m-none-eabi 2>&1 \
+// RUN:   | FileCheck -check-prefix=C-ARM-BAREMETAL %s
+
+// C-ARM-BAREMETAL: "-cc1" "-triple" "thumbv6m-unknown-none-eabi"
+// C-ARM-BAREMETAL: "-isysroot" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi"
+// C-ARM-BAREMETAL: "-internal-isystem" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include"
+
+// RUN: %clang -### %s -fuse-ld= \
+// RUN:   --target=armv6m-none-eabi --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_arm_gcc_tree \
+// RUN:   --sysroot=  2>&1 \
+// RUN:   | FileCheck -check-prefix=C-ARM-BAREMETAL-NOSYSROOT %s
+
+// C-ARM-BAREMETAL-NOSYSROOT: "-cc1" "-triple" "thumbv6m-unknown-none-eabi"
+// C-ARM-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../armv6m-none-eabi/include"
+
+// RUN: %clangxx -### %s -fuse-ld= \
+// RUN:   --target=armv6m-none-eabi -stdlib=libstdc++ --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_arm_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_arm_gcc_tree/armv6m-none-eabi 2>&1 \
+// RUN:   | FileCheck -check-prefix=CXX-ARM-BAREMETAL %s
+
+// CXX-ARM-BAREMETAL: "-isysroot" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi"
+// CXX-ARM-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include/c++/8.2.1/armv6m-none-eabi"
+// CXX-ARM-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include/c++/8.2.1/backward"
+// CXX-ARM-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include/c++/8.2.1" 
+// CXX-ARM-BAREMETAL: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include"
+
+// RUN: %clangxx -### %s -fuse-ld= \
+// RUN:   --target=armv6m-none-eabi -stdlib=libstdc++ --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_arm_gcc_tree \
+// RUN:   --sysroot=  2>&1 \
+// RUN:   | FileCheck -check-prefix=CXX-ARM-BAREMETAL-NOSYSROOT %s
+
+// CXX-ARM-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../armv6m-none-eabi/include/c++/8.2.1/armv6m-none-eabi"
+// CXX-ARM-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../armv6m-none-eabi/include/c++/8.2.1/backward"
+// CXX-ARM-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../armv6m-none-eabi/include/c++/8.2.1"
+// CXX-ARM-BAREMETAL-NOSYSROOT: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../armv6m-none-eabi/include"
+
+// RUN: %clangxx -### %s -fuse-ld= \
+// RUN:   --target=armv6m-none-eabi -stdlib=libc++ --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_arm_gcc_tree \
+// RUN:   --sysroot=%S/Inputs/basic_arm_gcc_tree/armv6m-none-eabi 2>&1 \
+// RUN:   | FileCheck -check-prefix=CXX-ARM-BAREMETAL-LIBCXX %s
+
+// CXX-ARM-BAREMETAL-LIBCXX: "-isysroot" "{{.*}}Inputs/basic_arm_gcc_tree/armv6m-none-eabi"
+// CXX-ARM-BAREMETAL-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include/c++/v1"
+// CXX-ARM-BAREMETAL-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/armv6m-none-eabi/include"
+
+// RUN: %clangxx -### %s -fuse-ld= \
+// RUN:   --target=armv6m-none-eabi -stdlib=libc++ --rtlib=libgcc \
+// RUN:   --gcc-toolchain=%S/Inputs/basic_arm_gcc_tree \
+// RUN:   --sysroot=  2>&1 \
+// RUN:   | FileCheck -check-prefix=CXX-ARM-BAREMETAL-NOSYSROOT-LIBCXX %s
+
+// CXX-ARM-BAREMETAL-NOSYSROOT-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../armv6m-none-eabi/include/c++/v1"
+// CXX-ARM-BAREMETAL-NOSYSROOT-LIBCXX: "-internal-isystem" "{{.*}}/Inputs/basic_arm_gcc_tree/lib/gcc/armv6m-none-eabi/8.2.1/../../../../armv6m-none-eabi/include
\ No newline at end of file
diff --git a/clang/test/Driver/baremetal.cpp b/clang/test/Driver/baremetal.cpp
index 6d6255ef5970f..aa1d020333f36 100644
--- a/clang/test/Driver/baremetal.cpp
+++ b/clang/test/Driver/baremetal.cpp
@@ -196,6 +196,22 @@
 // CHECK-AARCH64-NO-HOST-INC-SAME: "-internal-isystem" "[[RESOURCE]]{{[/\\]+}}include"
 // CHECK-AARCH64-NO-HOST-INC-SAME: "-internal-isystem" "[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}include"
 
+// RUN: %clang -no-canonical-prefixes %s -### --target=riscv32-unknown-elf 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RISCV32-NO-HOST-INC %s
+// CHECK-RISCV32-NO-HOST-INC: InstalledDir: [[INSTALLEDDIR:.+]]
+// CHECK-RISCV32-NO-HOST-INC: "-resource-dir" "[[RESOURCE:[^"]+]]"
+// CHECK-RISCV32-NO-HOST-INC-SAME: "-internal-isystem" "[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}include{{[/\\]+}}c++{{[/\\]+}}v1"
+// CHECK-RISCV32-NO-HOST-INC-SAME: "-internal-isystem" "[[RESOURCE]]{{[/\\]+}}include"
+// CHECK-RISCV32-NO-HOST-INC-SAME: "-internal-isystem" "[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}include"
+
+// RUN: %clang -no-canonical-prefixes %s -### --target=riscv64-unknown-elf 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-RISCV64-NO-HOST-INC %s
+// CHECK-RISCV64-NO-HOST-INC: InstalledDir: [[INSTALLEDDIR:.+]]
+// CHECK-RISCV64-NO-HOST-INC: "-resource-dir" "[[RESOURCE:[^"]+]]"
+// CHECK-RISCV64-NO-HOST-INC-SAME: "-internal-isystem" "[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}include{{[/\\]+}}c++{{[/\\]+}}v1"
+// CHECK-RISCV64-NO-HOST-INC-SAME: "-internal-isystem" "[[RESOURCE]]{{[/\\]+}}include"
+// CHECK-RISCV64-NO-HOST-INC-SAME: "-internal-isystem" "[[INSTALLEDDIR]]{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}clang-runtimes{{[/\\]+[^"]*}}include"
+
 // RUN: %clang %s -### --target=riscv64-unknown-elf -o %t.out -L some/directory/user/asked/for \
 // RUN:     --sysroot=%S/Inputs/basic_riscv64_tree/riscv64-unknown-elf 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-RV64 %s