detect dlfcn.h and dladdr in clang

Author: abhina-sree

clang/CMakeLists.txt

@@ -167,6 +167,23 @@ endif()
 include(CheckIncludeFile)
 check_include_file(sys/resource.h CLANG_HAVE_RLIMITS)
 
+# This check requires _GNU_SOURCE on linux
+check_include_file(dlfcn.h CLANG_HAVE_DLFCN_H)
+if( CLANG_HAVE_DLFCN_H )
+  include(CheckLibraryExists)
+  include(CheckSymbolExists)
+  check_library_exists(dl dlopen "" HAVE_LIBDL)
+  if( HAVE_LIBDL )
+    list(APPEND CMAKE_REQUIRED_LIBRARIES dl)
+  endif()
+  list(APPEND CMAKE_REQUIRED_DEFINITIONS -D_GNU_SOURCE)
+  check_symbol_exists(dladdr dlfcn.h CLANG_HAVE_DLADDR)
+  list(REMOVE_ITEM CMAKE_REQUIRED_DEFINITIONS -D_GNU_SOURCE)
+  if( HAVE_LIBDL )
+    list(REMOVE_ITEM CMAKE_REQUIRED_LIBRARIES dl)
+  endif()
+endif()
+
 set(CLANG_RESOURCE_DIR "" CACHE STRING
   "Relative directory from the Clang binary to its resource files.")
 

clang/include/clang/Config/config.h.cmake

@@ -57,6 +57,12 @@
 /* Define if we have sys/resource.h (rlimits) */
 #cmakedefine CLANG_HAVE_RLIMITS ${CLANG_HAVE_RLIMITS}
 
+/* Define if we have dlfcn.h */
+#cmakedefine CLANG_HAVE_DLFCN_H ${CLANG_HAVE_DLFCN_H}
+
+/* Define if dladdr() is available on this platform. */
+#cmakedefine CLANG_HAVE_DLADDR ${CLANG_HAVE_DLADDR}
+
 /* Linker version detected at compile time. */
 #cmakedefine HOST_LINK_VERSION "${HOST_LINK_VERSION}"
 

clang/tools/libclang/CIndexer.cpp

@@ -14,10 +14,10 @@
 #include "CXString.h"
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/Version.h"
+#include "clang/Config/config.h"
 #include "clang/Driver/Driver.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
-#include "llvm/Config/config.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MD5.h"
 #include "llvm/Support/Path.h"
@@ -127,7 +127,7 @@ const std::string &CIndexer::getClangResourcesPath() {
   getClangResourcesPathImplAIX(LibClangPath);
 #else
   bool PathFound = false;
-#if defined(HAVE_DLFCN_H) && defined(HAVE_DLADDR)
+#if defined(CLANG_HAVE_DLFCN_H) && defined(CLANG_HAVE_DLADDR)
   Dl_info info;
   // This silly cast below avoids a C++ warning.
   if (dladdr((void *)(uintptr_t)clang_createTranslationUnit, &info) != 0) {