diff --git a/clang/test/Index/record-completion-invocation.c b/clang/test/Index/record-completion-invocation.c
--- a/clang/test/Index/record-completion-invocation.c
+++ b/clang/test/Index/record-completion-invocation.c
@@ -8,4 +8,4 @@
 // RUN: env LIBCLANG_DISABLE_CRASH_RECOVERY=1 CINDEXTEST_INVOCATION_EMISSION_PATH=%t not --crash c-index-test -code-completion-at=%s:10:1 "-remap-file=%s,%S/Inputs/record-parsing-invocation-remap.c" %s
 // RUN: cat %t/libclang-* | FileCheck %s
 
-// CHECK: {"toolchain":"{{.*}}","libclang.operation":"complete","libclang.opts":1,"args":["clang","-fno-spell-checking","{{.*}}record-completion-invocation.c","-Xclang","-detailed-preprocessing-record","-fallow-editor-placeholders"],"invocation-args":["-code-completion-at={{.*}}record-completion-invocation.c:10:1"],"unsaved_file_hashes":[{"name":"{{.*}}record-completion-invocation.c","md5":"aee23773de90e665992b48209351d70e"}]}
+// CHECK: {"toolchain":"{{.*}}","libclang.operation":"complete","libclang.opts":1,"args":["{{.*}}clang","-fno-spell-checking","{{.*}}record-completion-invocation.c","-Xclang","-detailed-preprocessing-record","-fallow-editor-placeholders"],"invocation-args":["-code-completion-at={{.*}}record-completion-invocation.c:10:1"],"unsaved_file_hashes":[{"name":"{{.*}}record-completion-invocation.c","md5":"aee23773de90e665992b48209351d70e"}]}
diff --git a/clang/test/Index/record-parsing-invocation.c b/clang/test/Index/record-parsing-invocation.c
--- a/clang/test/Index/record-parsing-invocation.c
+++ b/clang/test/Index/record-parsing-invocation.c
@@ -24,5 +24,5 @@
 #  pragma clang __debug parser_crash
 #endif
 
-// CHECK: {"toolchain":"{{.*}}","libclang.operation":"parse","libclang.opts":1,"args":["clang","-fno-spell-checking","{{.*}}record-parsing-invocation.c","-Xclang","-detailed-preprocessing-record","-fallow-editor-placeholders"]}
-// CHECK-UNSAVED: {"toolchain":"{{.*}}","libclang.operation":"parse","libclang.opts":1,"args":["clang","-fno-spell-checking","{{.*}}record-parsing-invocation.c","-Xclang","-detailed-preprocessing-record","-fallow-editor-placeholders"],"unsaved_file_hashes":[{"name":"{{.*}}record-parsing-invocation.c","md5":"aee23773de90e665992b48209351d70e"}]}
+// CHECK: {"toolchain":"{{.*}}","libclang.operation":"parse","libclang.opts":1,"args":["{{.*}}clang","-fno-spell-checking","{{.*}}record-parsing-invocation.c","-Xclang","-detailed-preprocessing-record","-fallow-editor-placeholders"]}
+// CHECK-UNSAVED: {"toolchain":"{{.*}}","libclang.operation":"parse","libclang.opts":1,"args":["{{.*}}clang","-fno-spell-checking","{{.*}}record-parsing-invocation.c","-Xclang","-detailed-preprocessing-record","-fallow-editor-placeholders"],"unsaved_file_hashes":[{"name":"{{.*}}record-parsing-invocation.c","md5":"aee23773de90e665992b48209351d70e"}]}
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -3543,12 +3543,15 @@
     const char *const *command_line_args, int num_command_line_args,
     struct CXUnsavedFile *unsaved_files, unsigned num_unsaved_files,
     unsigned options, CXTranslationUnit *out_TU) {
+  if (!CIdx)
+    return CXError_InvalidArguments;
   SmallVector<const char *, 4> Args;
-  Args.push_back("clang");
+  Args.push_back(static_cast<CIndexer *>(CIdx)->getClangBinaryPath().c_str());
   Args.append(command_line_args, command_line_args + num_command_line_args);
-  return clang_parseTranslationUnit2FullArgv(
+  CXErrorCode Ret = clang_parseTranslationUnit2FullArgv(
       CIdx, source_filename, Args.data(), Args.size(), unsaved_files,
       num_unsaved_files, options, out_TU);
+  return Ret;
 }
 
 enum CXErrorCode clang_parseTranslationUnit2FullArgv(
diff --git a/clang/tools/libclang/CIndexer.h b/clang/tools/libclang/CIndexer.h
--- a/clang/tools/libclang/CIndexer.h
+++ b/clang/tools/libclang/CIndexer.h
@@ -41,6 +41,7 @@
   std::shared_ptr<PCHContainerOperations> PCHContainerOps;
 
   std::string ToolchainPath;
+  std::string ClangBinaryPath;
 
   std::string InvocationEmissionPath;
 
@@ -56,7 +57,7 @@
   /// declarations.
   bool getOnlyLocalDecls() const { return OnlyLocalDecls; }
   void setOnlyLocalDecls(bool Local = true) { OnlyLocalDecls = Local; }
-  
+
   bool getDisplayDiagnostics() const { return DisplayDiagnostics; }
   void setDisplayDiagnostics(bool Display = true) {
     DisplayDiagnostics = Display;
@@ -78,6 +79,9 @@
 
   StringRef getClangToolchainPath();
 
+  /// Returns <ToolchainPath>/bin/clang.
+  const std::string &getClangBinaryPath();
+
   void setInvocationEmissionPath(StringRef Str) {
     InvocationEmissionPath = Str;
   }
diff --git a/clang/tools/libclang/CIndexer.cpp b/clang/tools/libclang/CIndexer.cpp
--- a/clang/tools/libclang/CIndexer.cpp
+++ b/clang/tools/libclang/CIndexer.cpp
@@ -88,6 +88,15 @@
   return ToolchainPath;
 }
 
+const std::string &CIndexer::getClangBinaryPath() {
+  if (!ClangBinaryPath.empty())
+    return ClangBinaryPath;
+  llvm::SmallString<128> Path;
+  llvm::sys::path::append(Path, getClangToolchainPath(), "bin", "clang");
+  ClangBinaryPath = Path.str();
+  return ClangBinaryPath;
+}
+
 LibclangInvocationReporter::LibclangInvocationReporter(
     CIndexer &Idx, OperationKind Op, unsigned ParseOptions,
     llvm::ArrayRef<const char *> Args,