Merge pull request #2486 from karwa/cross-compiling-modmap

Generate native glibc.modulemap when cross-compiling

Author: gribozavr

cmake/modules/AddSwift.cmake

@@ -180,7 +180,8 @@ function(_add_variant_swift_compile_flags
 
   list(APPEND result
       "-sdk" "${SWIFT_SDK_${sdk}_PATH}"
-      "-target" "${SWIFT_SDK_${sdk}_ARCH_${arch}_TRIPLE}")
+      "-target" "${SWIFT_SDK_${sdk}_ARCH_${arch}_TRIPLE}"
+      "-resource-dir" "${SWIFTLIB_DIR}")
 
   if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
     list(APPEND result

stdlib/public/Platform/CMakeLists.txt

@@ -37,29 +37,26 @@ foreach(sdk ${SWIFT_SDKS})
     foreach(arch ${SWIFT_SDK_${sdk}_ARCHITECTURES})
       set(arch_subdir "${SWIFT_SDK_${sdk}_LIB_SUBDIR}/${arch}")
       set(module_dir "${SWIFTLIB_DIR}/${arch_subdir}")
-
-      # Determine the location of glibc based on the target.
-      if(${sdk} STREQUAL "ANDROID")
-        set(GLIBC_INCLUDE_PATH "${SWIFT_ANDROID_SDK_PATH}/usr/include")
-        set(GLIBC_ARCH_INCLUDE_PATH ${GLIBC_INCLUDE_PATH})
-      else()
-        set(GLIBC_INCLUDE_PATH "/usr/include")
-        set(GLIBC_ARCH_INCLUDE_PATH ${GLIBC_INCLUDE_PATH})
-        if((${sdk} STREQUAL "LINUX" OR ${sdk} STREQUAL "FREEBSD") AND CMAKE_LIBRARY_ARCHITECTURE)
-          # FIXME: Some distributions install headers in
-          #        "/usr/include/x86_64-linux-gnu/sys/...". Here we use the host
-          #        machine's path, regardless of the SDK target we're building for.
-          #        This will break if cross-compiling from a distro that uses the
-          #        architecture as part of the path to a distro that does not.
-          set(GLIBC_ARCH_INCLUDE_PATH "${GLIBC_INCLUDE_PATH}/${CMAKE_LIBRARY_ARCHITECTURE}")
-        endif()
+      
+      # Determine the location of glibc headers based on the target.
+      set(GLIBC_SYSROOT_RELATIVE_INCLUDE_PATH "/usr/include")
+      set(GLIBC_SYSROOT_REALTIVE_ARCH_INCLUDE_PATH ${GLIBC_SYSROOT_RELATIVE_INCLUDE_PATH})
+      
+      # Some SDKs place their headers in architecture-specific subfolders.
+      if((${sdk} STREQUAL "LINUX" OR ${sdk} STREQUAL "FREEBSD") AND CMAKE_LIBRARY_ARCHITECTURE)
+        set(GLIBC_SYSROOT_REALTIVE_ARCH_INCLUDE_PATH "${GLIBC_SYSROOT_REALTIVE_ARCH_INCLUDE_PATH}/${CMAKE_LIBRARY_ARCHITECTURE}")
       endif()
 
+      set(GLIBC_INCLUDE_PATH "${SWIFT_SDK_${sdk}_PATH}/${GLIBC_SYSROOT_RELATIVE_INCLUDE_PATH}")
+      set(GLIBC_ARCH_INCLUDE_PATH "${SWIFT_SDK_${sdk}_PATH}/${GLIBC_SYSROOT_REALTIVE_ARCH_INCLUDE_PATH}")
+
       set(glibc_modulemap_source "glibc.modulemap.gyb")
       set(glibc_modulemap_out "${module_dir}/glibc.modulemap")
 
       # Configure the module map based on the target. Each platform needs to
       # reference different headers, based on what's available in their glibc.
+      # This is the 'glibc.modulemap' in the 'resource-dir', so 
+      # it's the one we'll look at during the build process.
       handle_gyb_source_single(glibc_modulemap_target
           SOURCE "${glibc_modulemap_source}"
           OUTPUT "${glibc_modulemap_out}"
@@ -68,11 +65,34 @@ foreach(sdk ${SWIFT_SDKS})
               "-DGLIBC_INCLUDE_PATH=${GLIBC_INCLUDE_PATH}"
               "-DGLIBC_ARCH_INCLUDE_PATH=${GLIBC_ARCH_INCLUDE_PATH}")
 
+      list(APPEND glibc_modulemap_target_list ${glibc_modulemap_target})
+
+      # If this SDK is a target for a non-native host, create a native modulemap 
+      # without a sysroot prefix. This is the one we'll install instead.
+      if(NOT "${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_PATH}" STREQUAL "/")
+
+        set(glibc_sysroot_relative_modulemap_out "${module_dir}/sysroot-relative-modulemaps/glibc.modulemap")
+        handle_gyb_source_single(glibc_modulemap_native_target
+            SOURCE "${glibc_modulemap_source}"
+            OUTPUT "${glibc_sysroot_relative_modulemap_out}"
+            FLAGS
+                "-DCMAKE_SDK=${sdk}"
+                "-DGLIBC_INCLUDE_PATH=${GLIBC_SYSROOT_RELATIVE_INCLUDE_PATH}"
+                "-DGLIBC_ARCH_INCLUDE_PATH=${GLIBC_SYSROOT_REALTIVE_ARCH_INCLUDE_PATH}")
+
+        list(APPEND glibc_modulemap_target_list ${glibc_modulemap_native_target})
+        set(glibc_modulemap_out ${glibc_sysroot_relative_modulemap_out})
+      endif()
+
+      # FIXME: When SDK is a cross-compile target (SDK != Host), the generated
+      #        modulemap will be relative to the Host, with hardcoded paths.
+      #        It is not relocatable to the target platform itself.
+      #        This only affects ANDROID right now, but could affect cross-compiled LINUX targets
+        
       swift_install_in_component(sdk-overlay
           FILES "${glibc_modulemap_out}"
           DESTINATION "lib/swift/${arch_subdir}")
 
-      list(APPEND glibc_modulemap_target_list ${glibc_modulemap_target})
     endforeach()
   endif()
 endforeach()