clang: Use sysroot relative paths for getArchSpecificLibPaths and getRuntimePath

Clang's default sysroot implementation differs that what we do in OE,
and we do it with gcc as well where we install c++ runtime headers in
target sysroot, clang does not by default it puts them relative to its
own installation and uses resourcedir to point to it. In order to solve
this we have to raise this question with respective upstreams or rethink
about how we package compiler runtime.

Upstream-Status: Inappropriate [OE-Specific]

Signed-off-by: Khem Raj <[email protected]>

Author: kraj

clang/lib/Driver/ToolChain.cpp

@@ -1025,7 +1025,10 @@ ToolChain::getTargetSubDirPath(StringRef BaseDir) const {
 }
 
 std::optional<std::string> ToolChain::getRuntimePath() const {
-  SmallString<128> P(D.ResourceDir);
+  SmallString<128> P(D.SysRoot);
+  StringRef ClangLibdirBasename(CLANG_INSTALL_LIBDIR_BASENAME);
+  llvm::sys::path::append(P, "/usr/", ClangLibdirBasename, "clang",
+                          CLANG_VERSION_STRING);
   llvm::sys::path::append(P, "lib");
   if (auto Ret = getTargetSubDirPath(P))
     return Ret;
@@ -1053,7 +1056,10 @@ ToolChain::path_list ToolChain::getArchSpecificLibPaths() const {
   path_list Paths;
 
   auto AddPath = [&](const ArrayRef<StringRef> &SS) {
-    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);
     llvm::sys::path::append(Path, "lib");
     for (auto &S : SS)
       llvm::sys::path::append(Path, S);