fixup! [Clang][Driver] Fix the missing Target-Triple-Level include path resolution in Baremetal Driver

Author: simpal01

clang/lib/Driver/ToolChains/BareMetal.cpp

@@ -494,8 +494,13 @@ void BareMetal::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
   if (SysRootDir.empty())
     return;
 
+  SmallString<128> Dir(SysRootDir);
+  llvm::sys::path::append(Dir, Target, "include", "c++", "v1");
+  if (D.getVFS().exists(Dir))
+    addSystemInclude(DriverArgs, CC1Args, Dir.str());
+
   for (const Multilib &M : getOrderedMultilibs()) {
-    SmallString<128> Dir(SysRootDir);
+    Dir = SysRootDir;
     llvm::sys::path::append(Dir, M.gccSuffix());
     switch (GetCXXStdlibType(DriverArgs)) {
     case ToolChain::CST_Libcxx: {
@@ -509,10 +514,6 @@ void BareMetal::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
       // Add generic paths if nothing else succeeded so far.
       llvm::sys::path::append(Dir, "include", "c++", "v1");
       addSystemInclude(DriverArgs, CC1Args, Dir.str());
-      Dir = SysRootDir;
-      llvm::sys::path::append(Dir, Target, "include", "c++", "v1");
-      if (D.getVFS().exists(Dir))
-        addSystemInclude(DriverArgs, CC1Args, Dir.str());
       break;
     }
     case ToolChain::CST_Libstdcxx: {

clang/test/Driver/Inputs/multiarch-sysroot-tree/aarch64-unknown-none-elf/include/c++/v1/.keep

@@ -4,6 +4,18 @@
 // RUN:   | FileCheck -check-prefixes=CHECK-STATIC-LIB %s
 // CHECK-STATIC-LIB: {{.*}}llvm-ar{{.*}}" "rcsD"
 
+// RUN: %clang %s -### --target=arm-none-eabi -o %t.out 2>&1 \
+// RUN:     --sysroot=%S/Inputs/multiarch-sysroot-tree \
+// RUN:   | FileCheck --check-prefix=CHECK-ARM %s
+// CHECK-ARM: "-internal-isystem" "{{[^"]+}}multiarch-sysroot-tree{{[/\\]+}}arm-unknown-none-eabi{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
+// CHECK-ARM: "-internal-isystem" "{{[^"]+}}multiarch-sysroot-tree{{[/\\]+}}arm-unknown-none-eabi{{[/\\]+}}include"
+
+// RUN: %clang %s -### --target=aarch64-none-elf -o %t.out 2>&1 \
+// RUN:     --sysroot=%S/Inputs/multiarch-sysroot-tree \
+// RUN:   | FileCheck --check-prefix=CHECK-AARCH64 %s
+// CHECK-AARCH64: "-internal-isystem" "{{[^"]+}}multiarch-sysroot-tree{{[/\\]+}}aarch64-unknown-none-elf{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
+// CHECK-AARCH64: "-internal-isystem" "{{[^"]+}}multiarch-sysroot-tree{{[/\\]+}}aarch64-unknown-none-elf{{[/\\]+}}include"
+
 // RUN: %clang %s -### --target=armv6m-none-eabi -o %t.out 2>&1 \
 // RUN:     -T semihosted.lds \
 // RUN:     -L some/directory/user/asked/for \