[R-package] replaced gendef.exe with R code to create R.def (fixes mi…

…crosoft#3064)

.gitignore

@@ -406,6 +406,7 @@ R-package/src-i386
 lightgbm_r/*
 lightgbm*.tar.gz
 lightgbm.Rcheck/
+*.def
 
 # Files created by R examples and tests
 **/lgb-Dataset.data

R-package/src/cmake/modules/FindLibR.cmake

@@ -41,20 +41,26 @@ function(create_rlib_for_msvc)
     message(FATAL_ERROR "LIBR_CORE_LIBRARY, '${LIBR_CORE_LIBRARY}', not found")
   endif()
 
-  find_program(GENDEF_EXE gendef)
+  # find_program(GENDEF_EXE gendef)
   find_program(DLLTOOL_EXE dlltool)
 
-  if(NOT GENDEF_EXE OR NOT DLLTOOL_EXE)
+  #if(NOT GENDEF_EXE OR NOT DLLTOOL_EXE)
+  if(NOT DLLTOOL_EXE)
     message(FATAL_ERROR "Either gendef.exe or dlltool.exe not found!\
       \nDo you have Rtools installed with its MinGW's bin/ in PATH?")
   endif()
 
   set(LIBR_MSVC_CORE_LIBRARY "${CMAKE_CURRENT_BINARY_DIR}/R.lib" CACHE PATH "R.lib filepath")
 
   # extract symbols from R.dll into R.def and R.lib import library
-  execute_process(COMMAND ${GENDEF_EXE}
-    "-" "${LIBR_CORE_LIBRARY}"
-    OUTPUT_FILE "${CMAKE_CURRENT_BINARY_DIR}/R.def"
+  #execute_process(COMMAND ${GENDEF_EXE}
+  #  "-" "${LIBR_CORE_LIBRARY}"
+  #  OUTPUT_FILE "${CMAKE_CURRENT_BINARY_DIR}/R.def"
+  #)
+  execute_process(
+    COMMAND "${LIBR_HOME}/bin/Rscript"
+    "${CMAKE_CURRENT_BINARY_DIR}/make-r-def.R"
+    "${LIBR_CORE_LIBRARY}" "${CMAKE_CURRENT_BINARY_DIR}/R.def"
   )
   execute_process(COMMAND ${DLLTOOL_EXE}
     "--input-def" "${CMAKE_CURRENT_BINARY_DIR}/R.def"

R-package/src/install.libs.R

@@ -109,6 +109,19 @@ if (!use_precompile) {
     , showWarnings = FALSE
   )
   setwd(build_dir)
+
+  # If using MSVC to build, pull in the file used
+  # to create R.def from R.dll
+  if (WINDOWS && !use_mingw){
+    write_succeeded <- file.copy(
+      "../../inst/bin/make-r-def.R"
+      , file.path(build_dir, "make-r-def.R")
+      , overwrite = TRUE
+    )
+    if (!write_succeeded) {
+      stop("Copying make-r-def.R failed")
+    }
+  }
 
   # Prepare installation steps
   cmake_args <- NULL

R-package/src/make-r-def.R

@@ -0,0 +1,64 @@
+# [description]
+#     Create a definition file (.def) from a .dll file, using objdump.
+#
+# [usage]
+# 
+#     Rscript make-r-def.R something.dll something.def
+#
+# [references]
+#    * https://www.cs.colorado.edu/~main/cs1300/doc/mingwfaq.html
+
+args <- commandArgs(trailingOnly = TRUE)
+
+IN_DLL_FILE <- args[[1]]
+OUT_DEF_FILE <- args[[2]]
+print(sprintf("Creating '%s' from '%s'", IN_DLL_FILE, OUT_DEF_FILE))
+
+# Creates a .def file from R.dll, using tools bundled with R4.0
+#LIBR_CORE_LIBRARY <- "C:/Program Files/R/R-3.6.1/bin/x64/R.dll"
+
+# use objdump to dump all the symbols
+OBJDUMP_FILE <- "R.fil"
+exit_code <- system2(
+    command = "objdump"
+    , args = c(
+        "-p"
+        , shQuote(IN_DLL_FILE)
+    )
+    , stdout = OBJDUMP_FILE
+)
+
+objdump_results <- readLines(OBJDUMP_FILE)
+file.remove(OBJDUMP_FILE)
+
+# Name Pointer table start
+# https://www.cs.colorado.edu/~main/cs1300/doc/mingwfaq.html
+start_index <- which(
+    grepl(
+        pattern = "[Ordinal/Name Pointer] Table"
+        , x = objdump_results
+        , fixed = TRUE
+    )
+)
+empty_lines <- which(objdump_results == "")
+end_of_table <- empty_lines[empty_lines > start_index][1]
+
+# Read the contents of the table
+exported_symbols <- objdump_results[(start_index + 1):end_of_table]
+exported_symbols <- gsub("\t", "", exported_symbols)
+exported_symbols <- gsub(".*\\] ", "", exported_symbols)
+exported_symbols <- gsub(" ", "", exported_symbols)
+
+# Write R.def file
+write_succeeded <- writeLines(
+    text = c(
+        paste0("LIBRARY ", '\"R.dll\"')
+        , "EXPORTS"
+        , exported_symbols
+    )
+    , con = OUT_DEF_FILE
+    , sep = "\n"
+)
+if (!isTRUE(write_succeeded)){
+    stop("Failed to create R.def")
+}

build_r.R

@@ -115,6 +115,13 @@ for (src_file in c("lightgbm_R.cpp", "lightgbm_R.h", "R_object_helper.h")) {
   .handle_result(result)
 }
 
+result <- file.copy(
+  from = file.path("R-package", "src", "make-r-def.R")
+  , to = file.path("lightgbm_r", "inst", "bin/")
+  , overwrite = TRUE
+)
+.handle_result(result)
+
 # NOTE: --keep-empty-dirs is necessary to keep the deep paths expected
 #       by CMake while also meeting the CRAN req to create object files
 #       on demand