[CMake] Move check for dlfcn.h and dladdr to clang

[abhina-sree]

This patch checks for the presence of dlfcn.h and dladdr in clang to be used in clang/tools/libclang/CIndexer.cpp

[llvmbot]

@llvm/pr-subscribers-clang

Author: Abhina Sree (abhina-sree)

Changes

This patch checks for the presence of dlfcn.h and dladdr in clang to be used in clang/tools/libclang/CIndexer.cpp

---

Full diff: https://github.com/llvm/llvm-project/pull/76163.diff

5 Files Affected:

• (modified) clang/CMakeLists.txt (+17)
• (modified) clang/include/clang/Config/config.h.cmake (+6)
• (modified) clang/tools/libclang/CIndexer.cpp (+2-2)
• (modified) llvm/include/llvm/Config/config.h.cmake (+6)
• (modified) llvm/include/llvm/Config/llvm-config.h.cmake (-6)

diff --git a/clang/CMakeLists.txt b/clang/CMakeLists.txt
index 2ca6db02e58791..9f814478c45503 100644
--- a/clang/CMakeLists.txt
+++ b/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.")
 
diff --git a/clang/include/clang/Config/config.h.cmake b/clang/include/clang/Config/config.h.cmake
index a54a26cd32ffe4..4015ac8040861c 100644
--- a/clang/include/clang/Config/config.h.cmake
+++ b/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}"
 
diff --git a/clang/tools/libclang/CIndexer.cpp b/clang/tools/libclang/CIndexer.cpp
index 430147b2aa77af..12d9d418dea51d 100644
--- a/clang/tools/libclang/CIndexer.cpp
+++ b/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/llvm-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) {
diff --git a/llvm/include/llvm/Config/config.h.cmake b/llvm/include/llvm/Config/config.h.cmake
index d464263c190a73..fc1f9bf342f8d5 100644
--- a/llvm/include/llvm/Config/config.h.cmake
+++ b/llvm/include/llvm/Config/config.h.cmake
@@ -50,9 +50,15 @@
    don't. */
 #cmakedefine01 HAVE_DECL_STRERROR_S
 
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#cmakedefine HAVE_DLFCN_H ${HAVE_DLFCN_H}
+
 /* Define if dlopen() is available on this platform. */
 #cmakedefine HAVE_DLOPEN ${HAVE_DLOPEN}
 
+/* Define if dladdr() is available on this platform. */
+#cmakedefine HAVE_DLADDR ${HAVE_DLADDR}
+
 /* Define to 1 if we can register EH frames on this platform. */
 #cmakedefine HAVE_REGISTER_FRAME ${HAVE_REGISTER_FRAME}
 
diff --git a/llvm/include/llvm/Config/llvm-config.h.cmake b/llvm/include/llvm/Config/llvm-config.h.cmake
index 483c5adc99ca80..6605ea60df99e1 100644
--- a/llvm/include/llvm/Config/llvm-config.h.cmake
+++ b/llvm/include/llvm/Config/llvm-config.h.cmake
@@ -198,10 +198,4 @@
 /* Define if plugins enabled */
 #cmakedefine LLVM_ENABLE_PLUGINS
 
-/* Define to 1 if you have the <dlfcn.h> header file. */
-#cmakedefine HAVE_DLFCN_H ${HAVE_DLFCN_H}
-
-/* Define if dladdr() is available on this platform. */
-#cmakedefine HAVE_DLADDR ${HAVE_DLADDR}
-
 #endif

[chapuni]

Thanks.

[abhina-sree]

CI failure is unrelated to my patch, so I will go ahead and commit

[nico]

Can you say what motivated this? Change looks fine, but it looks like it fixes a problem someone reported somewhere but this doesn't say what the problem is.

[abhina-sree]

Can you say what motivated this? Change looks fine, but it looks like it fixes a problem someone reported somewhere but this doesn't say what the problem is.

Yes, there was a concern about exposing prefix-less macros in the llvm-config.h here #75928 (comment)

[nico]

Thanks!