[CMake] Simplify CMake handling for libxml2

This matches the changes made to handling of zlib done in 10b1b4a
where we rely on find_package and the imported target rather than
manually appending the library and include paths. The use of
LLVM_LIBXML2_ENABLED has been replaced by LLVM_ENABLE_LIBXML2
thus reducing the number of variables.

Differential Revision: https://reviews.llvm.org/D84563

cmake/config-ix.cmake

@@ -137,6 +137,27 @@ if(LLVM_ENABLE_ZLIB)
   set(LLVM_ENABLE_ZLIB "${HAVE_ZLIB}")
 endif()
 
+if(LLVM_ENABLE_LIBXML2)
+  if(LLVM_ENABLE_LIBXML2 STREQUAL FORCE_ON)
+    find_package(LibXml2 REQUIRED)
+  elseif(NOT LLVM_USE_SANITIZER MATCHES "Memory.*")
+    find_package(LibXml2)
+  endif()
+  if(LibXml2_FOUND)
+    # Check if libxml2 we found is usable; for example, we may have found a 32-bit
+    # library on a 64-bit system which would result in a link-time failure.
+    cmake_push_check_state()
+    set(CMAKE_REQUIRED_INCLUDES ${LIBXML2_INCLUDE_DIRS})
+    set(CMAKE_REQUIRED_LIBRARIES ${LIBXML2_LIBRARIES})
+    check_symbol_exists(xmlReadMemory libxml/xmlreader.h HAVE_LIBXML2)
+    cmake_pop_check_state()
+    if(LLVM_ENABLE_LIBXML2 STREQUAL FORCE_ON AND NOT HAVE_LIBXML2)
+      message(FATAL_ERROR "Failed to configure libxml2")
+    endif()
+  endif()
+  set(LLVM_ENABLE_LIBXML2 "${HAVE_LIBXML2}")
+endif()
+
 # Don't look for these libraries if we're using MSan, since uninstrumented third
 # party code may call MSan interceptors like strlen, leading to false positives.
 if(NOT LLVM_USE_SANITIZER MATCHES "Memory.*")
@@ -161,21 +182,6 @@ if(NOT LLVM_USE_SANITIZER MATCHES "Memory.*")
     else()
       set(LLVM_ENABLE_TERMINFO 0)
     endif()
-
-    find_library(ICONV_LIBRARY_PATH NAMES iconv libiconv libiconv-2 c)
-    set(LLVM_LIBXML2_ENABLED 0)
-    set(LIBXML2_FOUND 0)
-    if((LLVM_ENABLE_LIBXML2) AND ((CMAKE_SYSTEM_NAME MATCHES "Linux") AND (ICONV_LIBRARY_PATH) OR APPLE))
-      find_package(LibXml2)
-      if (LIBXML2_FOUND)
-        set(LLVM_LIBXML2_ENABLED 1)
-        if ((CMAKE_OSX_SYSROOT) AND (EXISTS ${CMAKE_OSX_SYSROOT}/${LIBXML2_INCLUDE_DIR}))
-          include_directories(${CMAKE_OSX_SYSROOT}/${LIBXML2_INCLUDE_DIR})
-        else()
-          include_directories(${LIBXML2_INCLUDE_DIR})
-        endif()
-      endif()
-    endif()
   else()
     set(LLVM_ENABLE_TERMINFO 0)
   endif()
@@ -183,10 +189,6 @@ else()
   set(LLVM_ENABLE_TERMINFO 0)
 endif()
 
-if (LLVM_ENABLE_LIBXML2 STREQUAL "FORCE_ON" AND NOT LLVM_LIBXML2_ENABLED)
-  message(FATAL_ERROR "Failed to congifure libxml2")
-endif()
-
 check_library_exists(xar xar_open "" HAVE_LIBXAR)
 if(HAVE_LIBXAR)
   set(XAR_LIB xar)

cmake/modules/GetLibraryName.cmake

@@ -0,0 +1,17 @@
+# Returns library name for a given path.
+function(get_library_name path name)
+  get_filename_component(path ${path} NAME)
+  set(prefixes ${CMAKE_FIND_LIBRARY_PREFIXES})
+  set(suffixes ${CMAKE_FIND_LIBRARY_SUFFIXES})
+  list(FILTER prefixes EXCLUDE REGEX "^\\s*$")
+  list(FILTER suffixes EXCLUDE REGEX "^\\s*$")
+  if(prefixes)
+    string(REPLACE ";" "|" prefixes "${prefixes}")
+    string(REGEX REPLACE "^(${prefixes})" "" path ${path})
+  endif()
+  if(suffixes)
+    string(REPLACE ";" "|" suffixes "${suffixes}")
+    string(REGEX REPLACE "(${suffixes})$" "" path ${path})
+  endif()
+  set(${name} "${path}" PARENT_SCOPE)
+endfunction()

cmake/modules/LLVMConfig.cmake.in

@@ -55,7 +55,10 @@ if(LLVM_ENABLE_ZLIB)
   find_package(ZLIB)
 endif()
 
-set(LLVM_LIBXML2_ENABLED @LLVM_LIBXML2_ENABLED@)
+set(LLVM_ENABLE_LIBXML2 @LLVM_ENABLE_LIBXML2@)
+if(LLVM_ENABLE_LIBXML2)
+  find_package(LibXml2)
+endif()
 
 set(LLVM_WITH_Z3 @LLVM_WITH_Z3@)
 

include/llvm/Config/config.h.cmake

@@ -306,7 +306,7 @@
 #cmakedefine01 LLVM_VERSION_PRINTER_SHOW_HOST_TARGET_INFO
 
 /* Define if libxml2 is supported on this platform. */
-#cmakedefine LLVM_LIBXML2_ENABLED ${LLVM_LIBXML2_ENABLED}
+#cmakedefine LLVM_ENABLE_LIBXML2 ${LLVM_ENABLE_LIBXML2}
 
 /* Define to the extension used for shared libraries, say, ".so". */
 #cmakedefine LTDL_SHLIB_EXT "${LTDL_SHLIB_EXT}"

lib/Support/CMakeLists.txt

@@ -1,24 +1,9 @@
+include(GetLibraryName)
+
 if(LLVM_ENABLE_ZLIB)
   set(imported_libs ZLIB::ZLIB)
 endif()
 
-function(get_system_libname libpath libname)
-  get_filename_component(libpath ${libpath} NAME)
-  set(prefixes ${CMAKE_FIND_LIBRARY_PREFIXES})
-  set(suffixes ${CMAKE_FIND_LIBRARY_SUFFIXES})
-  list(FILTER prefixes EXCLUDE REGEX "^\\s*$")
-  list(FILTER suffixes EXCLUDE REGEX "^\\s*$")
-  if( prefixes )
-    string(REPLACE ";" "|" prefixes "${prefixes}")
-    string(REGEX REPLACE "^(${prefixes})" "" libpath ${libpath})
-  endif()
-  if( suffixes )
-    string(REPLACE ";" "|" suffixes "${suffixes}")
-    string(REGEX REPLACE "(${suffixes})$" "" libpath ${libpath})
-  endif()
-  set(${libname} "${libpath}" PARENT_SCOPE)
-endfunction()
-
 if( MSVC OR MINGW )
   # libuuid required for FOLDERID_Profile usage in lib/Support/Windows/Path.inc.
   # advapi32 required for CryptAcquireContextW in lib/Support/Windows/Path.inc.
@@ -242,6 +227,8 @@ add_llvm_component_library(LLVMSupport
 
 set(llvm_system_libs ${system_libs})
 
+# This block is only needed for llvm-config. When we deprecate llvm-config and
+# move to using CMake export, this block can be removed.
 if(LLVM_ENABLE_ZLIB)
   # CMAKE_BUILD_TYPE is only meaningful to single-configuration generators.
   if(CMAKE_BUILD_TYPE)
@@ -251,12 +238,12 @@ if(LLVM_ENABLE_ZLIB)
   if(NOT zlib_library)
     get_property(zlib_library TARGET ZLIB::ZLIB PROPERTY LOCATION)
   endif()
-  get_system_libname(${zlib_library} zlib_library)
+  get_library_name(${zlib_library} zlib_library)
   set(llvm_system_libs ${llvm_system_libs} "${zlib_library}")
 endif()
 
 if(LLVM_ENABLE_TERMINFO)
-  get_system_libname(${TERMINFO_LIB} terminfo_library)
+  get_library_name(${TERMINFO_LIB} terminfo_library)
   set(llvm_system_libs ${llvm_system_libs} "${terminfo_library}")
 endif()
 

lib/WindowsManifest/CMakeLists.txt

@@ -1,23 +1,28 @@
+include(GetLibraryName)
+
+if(LLVM_ENABLE_LIBXML2)
+  set(imported_libs LibXml2::LibXml2)
+endif()
+
 add_llvm_component_library(LLVMWindowsManifest
   WindowsManifestMerger.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/WindowsManifest
-  ${Backtrace_INCLUDE_DIRS})
+  ${Backtrace_INCLUDE_DIRS}
+  LINK_LIBS ${imported_libs})
 
-if(LIBXML2_LIBRARIES)
+# This block is only needed for llvm-config. When we deprecate llvm-config and
-  target_link_libraries(LLVMWindowsManifest PUBLIC ${LIBXML2_LIBRARIES})
+# move to using CMake export, this block can be removed.
-
+if(LLVM_ENABLE_LIBXML2)
-  get_filename_component(xml2_library ${LIBXML2_LIBRARIES} NAME)
+  # CMAKE_BUILD_TYPE is only meaningful to single-configuration generators.
-  if (CMAKE_STATIC_LIBRARY_PREFIX AND
+  if(CMAKE_BUILD_TYPE)
-      xml2_library MATCHES "^${CMAKE_STATIC_LIBRARY_PREFIX}.*${CMAKE_STATIC_LIBRARY_SUFFIX}$")
+    string(TOUPPER ${CMAKE_BUILD_TYPE} build_type)
-    string(REGEX REPLACE "^${CMAKE_STATIC_LIBRARY_PREFIX}" "" xml2_library ${xml2_library})
+    get_property(libxml2_library TARGET LibXml2::LibXml2 PROPERTY LOCATION_${build_type})
-    string(REGEX REPLACE "${CMAKE_STATIC_LIBRARY_SUFFIX}$" "" xml2_library ${xml2_library})
-  elseif (CMAKE_SHARED_LIBRARY_PREFIX AND
-          xml2_library MATCHES "^${CMAKE_SHARED_LIBRARY_PREFIX}.*${CMAKE_SHARED_LIBRARY_SUFFIX}$")
-    string(REGEX REPLACE "^${CMAKE_SHARED_LIBRARY_PREFIX}" "" xml2_library ${xml2_library})
-    string(REGEX REPLACE "${CMAKE_SHARED_LIBRARY_SUFFIX}$" "" xml2_library ${xml2_library})
   endif()
-  set_property(TARGET LLVMWindowsManifest PROPERTY
+  if(NOT zlib_library)
-    LLVM_SYSTEM_LIBS ${xml2_library})
+    get_property(libxml2_library TARGET LibXml2::LibXml2 PROPERTY LOCATION)
+  endif()
+  get_library_name(${libxml2_library} libxml2_library)
+  set_property(TARGET LLVMWindowsManifest PROPERTY LLVM_SYSTEM_LIBS ${libxml2_library})
 endif()

lib/WindowsManifest/WindowsManifestMerger.cpp

@@ -16,7 +16,7 @@
 
 #include <map>
 
-#if LLVM_LIBXML2_ENABLED
+#if LLVM_ENABLE_LIBXML2
 #include <libxml/xmlreader.h>
 #endif
 
@@ -41,7 +41,7 @@ public:
 private:
   static void errorCallback(void *Ctx, const char *Format, ...);
   Error getParseError();
-#if LLVM_LIBXML2_ENABLED
+#if LLVM_ENABLE_LIBXML2
   xmlDocPtr CombinedDoc = nullptr;
   std::vector<xmlDocPtr> MergedDocs;
 
@@ -56,7 +56,7 @@ private:
   bool ParseErrorOccurred = false;
 };
 
-#if LLVM_LIBXML2_ENABLED
+#if LLVM_ENABLE_LIBXML2
 
 static constexpr std::pair<StringLiteral, StringLiteral> MtNsHrefsPrefixes[] = {
     {"urn:schemas-microsoft-com:asm.v1", "ms_asmv1"},

test/CMakeLists.txt

@@ -7,8 +7,8 @@ llvm_canonicalize_cmake_booleans(
   LLVM_ENABLE_FFI
   LLVM_ENABLE_THREADS
   LLVM_ENABLE_ZLIB
+  LLVM_ENABLE_LIBXML2
   LLVM_INCLUDE_GO_TESTS
-  LLVM_LIBXML2_ENABLED
   LLVM_LINK_LLVM_DYLIB
   LLVM_TOOL_LTO_BUILD
   LLVM_USE_INTEL_JITEVENTS

test/lit.cfg.py

@@ -356,7 +356,7 @@ if config.have_libxar:
 if config.enable_threads:
     config.available_features.add('thread_support')
 
-if config.llvm_libxml2_enabled:
+if config.have_libxml2:
     config.available_features.add('libxml2')
 
 if config.have_opt_viewer_modules:

test/lit.site.cfg.py.in

@@ -35,13 +35,13 @@ config.llvm_use_intel_jitevents = @LLVM_USE_INTEL_JITEVENTS@
 config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@"
 config.have_zlib = @LLVM_ENABLE_ZLIB@
 config.have_libxar = @HAVE_LIBXAR@
+config.have_libxml2 = @LLVM_ENABLE_LIBXML2@
 config.have_dia_sdk = @LLVM_ENABLE_DIA_SDK@
 config.enable_ffi = @LLVM_ENABLE_FFI@
 config.build_examples = @LLVM_BUILD_EXAMPLES@
 config.enable_threads = @LLVM_ENABLE_THREADS@
 config.build_shared_libs = @BUILD_SHARED_LIBS@
 config.link_llvm_dylib = @LLVM_LINK_LLVM_DYLIB@
-config.llvm_libxml2_enabled = @LLVM_LIBXML2_ENABLED@
 config.llvm_host_triple = '@LLVM_HOST_TRIPLE@'
 config.host_arch = "@HOST_ARCH@"
 config.have_opt_viewer_modules = @LLVM_HAVE_OPT_VIEWER_MODULES@

utils/gn/secondary/lld/test/BUILD.gn

@@ -43,9 +43,9 @@ write_lit_cfg("lit_site_cfg") {
   }
 
   if (llvm_enable_libxml2) {
-    extra_values += [ "LLVM_LIBXML2_ENABLED=1" ]
+    extra_values += [ "LLVM_ENABLE_LIBXML2=1" ]
   } else {
-    extra_values += [ "LLVM_LIBXML2_ENABLED=0" ]  # Must be 0.
+    extra_values += [ "LLVM_ENABLE_LIBXML2=0" ]  # Must be 0.
   }
 
   if (llvm_enable_zlib) {

utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn

@@ -304,9 +304,9 @@ write_cmake_config("config") {
   }
 
   if (llvm_enable_libxml2) {
-    values += [ "LLVM_LIBXML2_ENABLED=1" ]
+    values += [ "LLVM_ENABLE_LIBXML2=1" ]
   } else {
-    values += [ "LLVM_LIBXML2_ENABLED=" ]
+    values += [ "LLVM_ENABLE_LIBXML2=" ]
   }
 }
 

utils/gn/secondary/llvm/test/BUILD.gn

@@ -162,9 +162,9 @@ write_lit_config("lit_site_cfg") {
   }
 
   if (llvm_enable_libxml2) {
-    extra_values += [ "LLVM_LIBXML2_ENABLED=1" ]
+    extra_values += [ "LLVM_ENABLE_LIBXML2=1" ]
   } else {
-    extra_values += [ "LLVM_LIBXML2_ENABLED=0" ]  # Must be 0.
+    extra_values += [ "LLVM_ENABLE_LIBXML2=0" ]  # Must be 0.
   }
 
   if (llvm_enable_threads) {