Library Forwarding: Allow building guest libs in isolation

CMakeLists.txt

@@ -7,8 +7,9 @@ CHECK_INCLUDE_FILES ("gdb/jit-reader.h" HAVE_GDB_JIT_READER_H)
 option(BUILD_TESTS "Build unit tests to ensure sanity" TRUE)
 option(BUILD_FEX_LINUX_TESTS "Build FEXLinuxTests, requires x86 compiler" FALSE)
 option(BUILD_THUNKS "Build thunks" FALSE)
-option(BUILD_FEXCONFIG "Build FEXConfig, requires SDL2 and X11" TRUE)
 option(ENABLE_CLANG_THUNKS "Build thunks with clang" FALSE)
+option(BUILD_GUEST_LIBS "Build guest library wrappers as part of the main project" TRUE)
+option(BUILD_FEXCONFIG "Build FEXConfig, requires SDL2 and X11" TRUE)
 option(ENABLE_IWYU "Enables include what you use program" FALSE)
 option(ENABLE_LTO "Enable LTO with compilation" TRUE)
 option(ENABLE_XRAY "Enable building with LLVM X-Ray" FALSE)

ThunkLibs/CMakeLists.txt

@@ -1,19 +1,44 @@
-  include(ExternalProject)
+cmake_minimum_required(VERSION 3.14)
+project(FEXLibWrappers)
+
+set(CMAKE_CXX_STANDARD 20)
+set(FEX_PROJECT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/..)
+
+add_subdirectory(Generator)
 
-  set (FEX_PROJECT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/..)
-  add_subdirectory(Generator)
+# Two methods of building guest library wrappers are supported:
+# - build as part of the main project (recommended)
+# - build in isolation from a dedicated build folder
+# The second method is useful when it's difficult to set up a full
+# cross-compiling environment targeting x86. In those cases, guest library
+# compilation can be moved to a different machine / VM.
+if (NOT CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
+  # When included during a regular FEX build, build both guest and host libs
+  # unless requested otherwise
+  set(BUILD_HOST_LIBS TRUE)
+  set(BUILD_GUEST_LIBS ${BUILD_GUEST_LIBS})
 
-  # Thunk targets for IDE integration of guest code, only
+  # However, include targets for IDE integration of guest libs
   add_subdirectory(GuestLibs)
+else()
+  # When included on our own, only build guest libraries
+  set(BUILD_HOST_LIBS FALSE)
+  set(BUILD_GUEST_LIBS TRUE)
+endif()
 
-  # Thunk targets for both host libraries and IDE integration
+if (BUILD_HOST_LIBS)
+  # Targets for building host libraries and for IDE integration
   add_subdirectory(HostLibs)
+endif()
+
+if (BUILD_GUEST_LIBS)
+  # Targets for building guest libraries
+  include(ExternalProject)
 
-  # Thunk targets for guest libraries
   ExternalProject_Add(guest-libs
     PREFIX Guest/guest-libs
     SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/GuestLibs"
-    BINARY_DIR "Guest"
+    BINARY_DIR "../Guest"
     CMAKE_ARGS
       "-DBITNESS=64"
       "-DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}"
@@ -31,7 +56,7 @@
   ExternalProject_Add(guest-libs-32
     PREFIX Guest_32/guest-libs-32
     SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/GuestLibs"
-    BINARY_DIR "Guest_32"
+    BINARY_DIR "../Guest_32"
     CMAKE_ARGS
       "-DBITNESS=32"
       "-DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}"
@@ -64,15 +89,18 @@
     DEPENDS guest-libs-32
   )
 
-  add_custom_target(uninstall_guest-libs
-    COMMAND ${CMAKE_COMMAND} "--build" "." "--target" "uninstall"
-    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/Guest
-  )
+  if (TARGET uninstall)
+    add_custom_target(uninstall_guest-libs
+      COMMAND ${CMAKE_COMMAND} "--build" "." "--target" "uninstall"
+      WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/Guest
+    )
 
-  add_custom_target(uninstall_guest-libs-32
-    COMMAND ${CMAKE_COMMAND} "--build" "." "--target" "uninstall"
-    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/Guest_32
-  )
+    add_custom_target(uninstall_guest-libs-32
+      COMMAND ${CMAKE_COMMAND} "--build" "." "--target" "uninstall"
+      WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/Guest_32
+    )
 
-  add_dependencies(uninstall uninstall_guest-libs)
-  add_dependencies(uninstall uninstall_guest-libs-32)
+    add_dependencies(uninstall uninstall_guest-libs)
+    add_dependencies(uninstall uninstall_guest-libs-32)
+  endif ()
+endif()

ThunkLibs/Generator/CMakeLists.txt

@@ -1,3 +1,8 @@
+if (NOT TARGET fmt)
+  set(FMT_INSTALL OFF)
+  add_subdirectory(../../External/fmt/ fmt)
+endif ()
+
 find_package(Clang REQUIRED CONFIG)
 find_package(OpenSSL REQUIRED COMPONENTS Crypto)