auto generate a phi config header (#52224)

.gitignore

@@ -28,6 +28,7 @@ paddle/phi/api/lib/sparse_bw_api.cc
 paddle/phi/api/lib/tensor_api.cc
 paddle/phi/api/lib/tensor_operants.cc
 paddle/phi/extension.h
+paddle/phi/config.h
 paddle/phi/include/*
 paddle/phi/infermeta/generated.*
 paddle/fluid/prim/api/generated_prim/*.cc

paddle/phi/CMakeLists.txt

+configure_file(config.h.in ${CMAKE_CURRENT_SOURCE_DIR}/config.h)
+
 # phi auto cmake utils
 include(phi)
 
@@ -52,6 +54,7 @@ file(
   "// Header file generated by paddle/phi/CMakeLists.txt for external users,\n// DO NOT edit or include it within paddle.\n\n#pragma once\n\n"
 )
 
+file(APPEND ${phi_extension_header_file} "#include \"paddle/phi/config.h\"\n\n")
 # generate inner headers include dir for users
 generate_unify_header(backends EXCLUDES context_pool_utils.h)
 generate_unify_header(core EXCLUDES cuda_stream.h)

paddle/phi/config.h.in

+// Header file generated by paddle/phi/CMakeLists.txt
+
+// Generate a compilation configuration to avoid compilation errors or
+// incompatibilities caused by using phi without defining a phi compilation
+// macro. At the same time, configuration file definition macros are more
+// readable than those defined through the compilation option `-D`.
+
+#pragma once
+
+#undef ON
+#undef OFF
+#define ON 1
+#define OFF 0
+
+// WITH_MKLDNN
+#if @WITH_MKLDNN@
+#undef PADDLE_WITH_MKLDNN
+#define PADDLE_WITH_MKLDNN
+#endif
+
+// WITH_CUSTOM_DEVICE
+#if @WITH_CUSTOM_DEVICE@
+#undef PADDLE_WITH_CUSTOM_DEVICE
+#undef PADDLE_WITH_CUSTOM_KERNEL
+#define PADDLE_WITH_CUSTOM_DEVICE
+#define PADDLE_WITH_CUSTOM_KERNEL
+#endif
+
+// WITH_ARM
+#if @WITH_ARM@
+#undef PADDLE_WITH_ARM
+#define PADDLE_WITH_ARM
+#endif
+
+#undef ON
+#undef OFF