clang: Look inside the target sysroot for compiler runtime

In OE compiler-rt and libc++ are built and staged into target
sysroot and not into resourcedir which is relative to clang
driver installation where the libraries are not instlled

Specific to cross compiling the way yocto/OE works

Upstream-Status: Pending
Signed-off-by: Khem Raj <raj.khem@gmail.com>

Author: kraj

clang/lib/Driver/ToolChain.cpp

@@ -16,6 +16,7 @@
 #include "ToolChains/InterfaceStubs.h"
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Sanitizers.h"
+#include "clang/Basic/Version.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/Action.h"
 #include "clang/Driver/Driver.h"
@@ -708,7 +709,10 @@ StringRef ToolChain::getOSLibName() const {
 }
 
 std::string ToolChain::getCompilerRTPath() const {
-  SmallString<128> Path(getDriver().ResourceDir);
+  SmallString<128> Path(getDriver().SysRoot);
+  StringRef ClangLibdirBasename(CLANG_INSTALL_LIBDIR_BASENAME);
+  llvm::sys::path::append(Path, "/usr/", ClangLibdirBasename, "clang",
+                            CLANG_VERSION_STRING);
   if (isBareMetal()) {
     llvm::sys::path::append(Path, "lib", getOSLibName());
     if (!SelectedMultilibs.empty()) {