Handles libffi on the CMake build.

Patch by arrowdodger!

llvm-svn: 123976

CMakeLists.txt

@@ -114,6 +114,10 @@ if(LLVM_ENABLE_TIMESTAMPS)
   set(ENABLE_TIMESTAMPS 1)
 endif()
 
+option(LLVM_ENABLE_FFI "Use libffi to call external functions from the interpreter" OFF)
+set(FFI_LIBRARY_DIR "" CACHE PATH "Additional directory, where CMake should search for libffi.so")
+set(FFI_INCLUDE_DIR "" CACHE PATH "Additional directory, where CMake should search for ffi.h or ffi/ffi.h")
+
 set(C_INCLUDE_DIRS "" CACHE STRING
   "Colon separated list of directories clang will search for headers.")
 

cmake/config-ix.cmake

@@ -190,6 +190,35 @@ llvm_find_program(fdp)
 llvm_find_program(dot)
 llvm_find_program(dotty)
 
+if( LLVM_ENABLE_FFI )
+  find_path(FFI_INCLUDE_PATH ffi.h PATHS ${FFI_INCLUDE_DIR})
+  if( FFI_INCLUDE_PATH )
+    set(FFI_HEADER ffi.h CACHE INTERNAL "")
+    set(HAVE_FFI_H 1 CACHE INTERNAL "")
+  else()
+    find_path(FFI_INCLUDE_PATH ffi/ffi.h PATHS ${FFI_INCLUDE_DIR})
+    if( FFI_INCLUDE_PATH )
+      set(FFI_HEADER ffi/ffi.h CACHE INTERNAL "")
+      set(HAVE_FFI_FFI_H 1 CACHE INTERNAL "")
+    endif()
+  endif()
+
+  if( NOT FFI_HEADER )
+    message(FATAL_ERROR "libffi includes are not found.")
+  endif()
+
+  find_library(FFI_LIBRARY_PATH ffi PATHS ${FFI_LIBRARY_DIR})
+  if( NOT FFI_LIBRARY_PATH )
+    message(FATAL_ERROR "libffi is not found.")
+  endif()
+
+  list(APPEND CMAKE_REQUIRED_LIBRARIES ${FFI_LIBRARY_PATH})
+  list(APPEND CMAKE_REQUIRED_INCLUDES ${FFI_INCLUDE_PATH})
+  check_symbol_exists(ffi_call ${FFI_HEADER} HAVE_FFI_CALL)
+  list(REMOVE_ITEM CMAKE_REQUIRED_INCLUDES ${FFI_INCLUDE_PATH})
+  list(REMOVE_ITEM CMAKE_REQUIRED_LIBRARIES ${FFI_LIBRARY_PATH})
+endif( LLVM_ENABLE_FFI )
+
 # Define LLVM_MULTITHREADED if gcc atomic builtins exists.
 include(CheckAtomic)
 

docs/CMake.html

@@ -338,6 +338,12 @@
     By default, <tt>&quot;-sv --no-progress-bar&quot;</tt>
     on Visual C++ and Xcode,
     <tt>&quot;-sv&quot;</tt> on others.</dd>
+
+  <dt><b>LLVM_ENABLE_FFI</b>:BOOL</dt>
+  <dd>Indicates whether LLVM Interpreter will be linked with Foreign
+    Function Interface library. If the library or its headers are
+    installed on a custom location, you can set the variables
+    FFI_INCLUDE_DIR and FFI_LIBRARY_DIR. Defaults to OFF.</dd>
 </dl>
 
 </div>

include/llvm/Config/config.h.cmake

@@ -130,13 +130,13 @@
 #cmakedefine HAVE_FENV_H ${HAVE_FENV_H}
 
 /* Define if libffi is available on this platform. */
-#undef HAVE_FFI_CALL
+#cmakedefine HAVE_FFI_CALL ${HAVE_FFI_CALL}
 
 /* Define to 1 if you have the <ffi/ffi.h> header file. */
-#undef HAVE_FFI_FFI_H
+#cmakedefine HAVE_FFI_FFI_H ${HAVE_FFI_FFI_H}
 
 /* Define to 1 if you have the <ffi.h> header file. */
-#undef HAVE_FFI_H
+#cmakedefine HAVE_FFI_H ${HAVE_FFI_H}
 
 /* Set to 1 if the finite function is found in <ieeefp.h> */
 #cmakedefine HAVE_FINITE_IN_IEEEFP_H ${HAVE_FINITE_IN_IEEEFP_H}

lib/ExecutionEngine/Interpreter/CMakeLists.txt

@@ -1,5 +1,21 @@
+# If the user required a custom path for ffi headers, use it on its
+# abolute form (see config-ix.cmake):
+if( FFI_INCLUDE_DIR )
+  include_directories( ${FFI_INCLUDE_PATH} )
+endif()
+
+# If the user required a custom path for libffi, use it on its abolute
+# form (see config-ix.cmake):
+if( FFI_LIBRARY_DIR )
+  link_directories( ${FFI_LIBRARY_PATH} )
+endif()
+
 add_llvm_library(LLVMInterpreter
   Execution.cpp
   ExternalFunctions.cpp
   Interpreter.cpp
   )
+
+if( LLVM_ENABLE_FFI )
+  target_link_libraries( LLVMInterpreter ffi )
+endif()