Enable cross-compilation

helium · Feb 18, 2021 · cdc3a10 · cdc3a10
1 parent 66a4903
commit cdc3a10
Show file tree

Hide file tree

Showing 2 changed files with 38 additions and 97 deletions.
diff --git a/README.md b/README.md
@@ -24,6 +24,11 @@ need `cmake` installed to build the required h3 core package.
 
 To run the tests run `make test`.
 
+## Cross compilation
+
+Cross-compilation requires the environment variable `ERTS_INCLUDE_DIR`
+defined as the target directory containing `erl_nif.h`,
+e.g. `ERTS_INCLUDE_DIR=target/usr/lib/erlang/erts-<VERSION>/include`.
 
 Usage
 -----

diff --git a/c_src/cmake/FindErlang.cmake b/c_src/cmake/FindErlang.cmake
@@ -15,126 +15,62 @@ This module provides the following imported targets, if found:
 ``Erlang::Erlang``
   Header only interface library suitible for compiling NIFs.
 
-``Erlang::EI``
-  Erlang interface library.
-
-``Erlang::ERTS``
-  Erlang runtime system library.
-
 Result Variables
 ^^^^^^^^^^^^^^^^
 
 This will define the following variables:
 
 ``Erlang_FOUND``
   True if the system has the Erlang library.
-``Erlang_RUNTIME``
-  The path to the Erlang runtime.
-``Erlang_COMPILE``
-  The path to the Erlang compiler.
-``Erlang_EI_PATH``
-  The path to the Erlang erl_interface path.
-``Erlang_ERTS_PATH``
-  The path to the Erlang erts path.
-``Erlang_EI_INCLUDE_DIRS``
-  /include appended to Erlang_EI_PATH.
-``Erlang_EI_LIBRARY_PATH``
-  /lib appended to Erlang_EI_PATH.
-``Erlang_ERTS_INCLUDE_DIRS``
-  /include appended to Erlang_ERTS_PATH.
-``Erlang_ERTS_LIBRARY_PATH``
-  /lib appended to Erlang_ERTS_PATH.
-
-#]=======================================================================]
-include(FindPackageHandleStandardArgs)
-
-SET(Erlang_BIN_PATH
-  $ENV{ERLANG_HOME}/bin
-  /opt/bin
-  /sw/bin
-  /usr/bin
-  /usr/local/bin
-  /opt/local/bin
-  )
 
-FIND_PROGRAM(Erlang_RUNTIME
-  NAMES erl
-  PATHS ${Erlang_BIN_PATH}
-  )
-
-FIND_PROGRAM(Erlang_COMPILE
-  NAMES erlc
-  PATHS ${Erlang_BIN_PATH}
-  )
+Cache Variables
+^^^^^^^^^^^^^^^
 
-EXECUTE_PROCESS(
-  COMMAND         erl -noshell -eval "io:format(\"~s\", [code:lib_dir()])" -s erlang halt
-  OUTPUT_VARIABLE Erlang_OTP_LIB_DIR
-  )
+The following cache variables may also be set:
 
-EXECUTE_PROCESS(
-  COMMAND         erl -noshell -eval "io:format(\"~s\", [code:root_dir()])" -s erlang halt
-  OUTPUT_VARIABLE Erlang_OTP_ROOT_DIR
-  )
-
-EXECUTE_PROCESS(
-  COMMAND         erl -noshell -eval "io:format(\"~s\",[filename:basename(code:lib_dir('erl_interface'))])" -s erlang halt
-  OUTPUT_VARIABLE Erlang_EI_DIR
-  )
+``Erlang_ERTS_INCLUDE_DIR``
+  Path to Erlang Runtime System headers.
 
-EXECUTE_PROCESS(
-  COMMAND         erl -noshell -eval "io:format(\"~s\",[filename:basename(code:lib_dir('erts'))])" -s erlang halt
-  OUTPUT_VARIABLE Erlang_ERTS_DIR
-  )
-
-SET(Erlang_EI_PATH           ${Erlang_OTP_LIB_DIR}/${Erlang_EI_DIR})
-SET(Erlang_EI_INCLUDE_DIRS   ${Erlang_OTP_LIB_DIR}/${Erlang_EI_DIR}/include)
-SET(Erlang_EI_LIBRARY_PATH   ${Erlang_OTP_LIB_DIR}/${Erlang_EI_DIR}/lib)
+#]=======================================================================]
+include(FindPackageHandleStandardArgs)
 
-SET(Erlang_ERTS_PATH         ${Erlang_OTP_ROOT_DIR}/${Erlang_ERTS_DIR})
-SET(Erlang_ERTS_INCLUDE_DIRS ${Erlang_OTP_ROOT_DIR}/${Erlang_ERTS_DIR}/include)
-SET(Erlang_ERTS_LIBRARY_PATH ${Erlang_OTP_ROOT_DIR}/${Erlang_ERTS_DIR}/lib)
+if(DEFINED ENV{ERTS_INCLUDE_DIR})
+  SET(Erlang_ERTS_INCLUDE_DIR $ENV{ERTS_INCLUDE_DIR})
+else()
+  SET(Erlang_BIN_PATH
+    $ENV{ERLANG_HOME}/bin
+    /opt/bin
+    /sw/bin
+    /usr/bin
+    /usr/local/bin
+    /opt/local/bin
+    )
+
+  EXECUTE_PROCESS(
+    COMMAND         erl -noshell -eval "io:format(\"~s\", [code:root_dir()])" -s erlang halt
+    OUTPUT_VARIABLE Erlang_OTP_ROOT_DIR
+    )
+
+  EXECUTE_PROCESS(
+    COMMAND         erl -noshell -eval "io:format(\"~s\",[filename:basename(code:lib_dir('erts'))])" -s erlang halt
+    OUTPUT_VARIABLE Erlang_ERTS_DIR
+    )
+
+  SET(Erlang_ERTS_INCLUDE_DIR ${Erlang_OTP_ROOT_DIR}/${Erlang_ERTS_DIR}/include)
+endif()
 
 FIND_PACKAGE_HANDLE_STANDARD_ARGS(
   Erlang
   DEFAULT_MSG
-  Erlang_RUNTIME
-  Erlang_COMPILE
-  Erlang_OTP_LIB_DIR
-  Erlang_OTP_ROOT_DIR
-  Erlang_EI_DIR
-  Erlang_ERTS_DIR
+  Erlang_ERTS_INCLUDE_DIR
   )
 
 if(Erlang_FOUND)
   if(NOT TARGET Erlang::Erlang)
     add_library(Erlang::Erlang INTERFACE IMPORTED)
     set_target_properties(Erlang::Erlang
       PROPERTIES
-      INTERFACE_INCLUDE_DIRECTORIES ${Erlang_OTP_ROOT_DIR}/usr/include
-      )
-  endif()
-
-  if(NOT TARGET Erlang::ERTS)
-    add_library(Erlang::ERTS STATIC IMPORTED)
-    set_target_properties(Erlang::ERTS
-      PROPERTIES
-      INTERFACE_INCLUDE_DIRECTORIES ${Erlang_ERTS_INCLUDE_DIRS}
-      IMPORTED_LOCATION             ${Erlang_ERTS_LIBRARY_PATH}/liberts.a
-      )
-  endif()
-
-  if(NOT TARGET Erlang::EI)
-    add_library(erlang_ei STATIC IMPORTED)
-    set_property(TARGET erlang_ei PROPERTY
-      IMPORTED_LOCATION ${Erlang_EI_LIBRARY_PATH}/libei.a
-      )
-    add_library(Erlang::EI INTERFACE IMPORTED)
-    set_property(TARGET Erlang::EI PROPERTY
-      INTERFACE_INCLUDE_DIRECTORIES ${Erlang_EI_INCLUDE_DIRS}
-      )
-    set_property(TARGET Erlang::EI PROPERTY
-      INTERFACE_LINK_LIBRARIES erlang_ei
+      INTERFACE_INCLUDE_DIRECTORIES ${Erlang_ERTS_INCLUDE_DIR}
       )
   endif()
 endif(Erlang_FOUND)