[Comgr] Specify clang exe path in Driver creation

Manually specifying ClangIncludePath is not needed if the driver
is created with the correct clang binary path as first argument.
This allows the driver to get the correct clang resource directory.

Fixes ROCm/ROCm-CompilerSupport#48
Submitting on behalf of github user @littlewu2508

Change-Id: I381e76d82f8acb3a1dd2969e837723554d6ff2ed

Author: lamb-j

amd/comgr/src/comgr-compiler.cpp

@@ -667,7 +667,8 @@ AMDGPUCompiler::executeInProcessDriver(ArrayRef<const char *> Args) {
   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs);
   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
   ProcessWarningOptions(Diags, *DiagOpts, /*ReportDiags=*/false);
-  Driver TheDriver("", "", Diags);
+
+  Driver TheDriver((Twine(env::getLLVMPath()) + "/bin/clang").str(), "", Diags);
   TheDriver.setTitle("AMDGPU Code Object Manager");
   TheDriver.setCheckInputsExist(false);
 
@@ -1030,11 +1031,6 @@ amd_comgr_status_t AMDGPUCompiler::addCompilationFlags() {
   HIPIncludePath = (Twine(env::getHIPPath()) + "/include").str();
   // HIP headers depend on hsa.h which is in ROCM_DIR/include.
   ROCMIncludePath = (Twine(env::getROCMPath()) + "/include").str();
-  ClangIncludePath =
-      (Twine(env::getLLVMPath()) + "/lib/clang/" + CLANG_VERSION_STRING).str();
-  ClangIncludePath2 = (Twine(env::getLLVMPath()) + "/lib/clang/" +
-                       CLANG_VERSION_STRING + "/include")
-                          .str();
 
   Args.push_back("-x");
 
@@ -1062,10 +1058,6 @@ amd_comgr_status_t AMDGPUCompiler::addCompilationFlags() {
     Args.push_back(ROCMIncludePath.c_str());
     Args.push_back("-isystem");
     Args.push_back(HIPIncludePath.c_str());
-    Args.push_back("-isystem");
-    Args.push_back(ClangIncludePath.c_str());
-    Args.push_back("-isystem");
-    Args.push_back(ClangIncludePath2.c_str());
     break;
   default:
     return AMD_COMGR_STATUS_ERROR_INVALID_ARGUMENT;