From 2be8ab460378455f82d719a872420fb5053f1bd5 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Wed, 2 Oct 2013 14:04:38 +0000
Subject: [PATCH] Enable building LTO on WIN32.

Enable building the LTO library (.lib and.dll) and llvm-lto.exe on Windows with
MSVC and Mingw as well as re-enabling the associated test.

Patch by Greg Bedwell!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191823 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/LTO/cfi_endproc.ll  |  1 -
 test/LTO/lit.local.cfg   |  2 +-
 tools/CMakeLists.txt     |  2 +-
 tools/lto/CMakeLists.txt | 20 +++++++++++++++++---
 4 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/test/LTO/cfi_endproc.ll b/test/LTO/cfi_endproc.ll
index 0a47b0225ee..ecb0ed506e6 100644
--- a/test/LTO/cfi_endproc.ll
+++ b/test/LTO/cfi_endproc.ll
@@ -17,4 +17,3 @@ define i32 @main(i32 %argc, i8** %argv) {
   call void @PR14512()
   ret i32 0
 }
-; XFAIL: win32
diff --git a/test/LTO/lit.local.cfg b/test/LTO/lit.local.cfg
index f61943a77af..7a70736aeac 100644
--- a/test/LTO/lit.local.cfg
+++ b/test/LTO/lit.local.cfg
@@ -2,5 +2,5 @@ targets = set(config.root.targets_to_build.split())
 if not 'X86' in targets:
   config.unsupported = True
 
-if config.root.host_os in ['Cygwin', 'MingW', 'Windows']:
+if config.root.host_os in ['Cygwin']:
   config.unsupported = True
diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index 468d396b59a..d8001e75a70 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -43,7 +43,7 @@ add_llvm_tool_subdirectory(llvm-symbolizer)
 add_llvm_tool_subdirectory(obj2yaml)
 add_llvm_tool_subdirectory(yaml2obj)
 
-if( NOT WIN32 )
+if( NOT CYGWIN )
   add_llvm_tool_subdirectory(lto)
   add_llvm_tool_subdirectory(llvm-lto)
 else()
diff --git a/tools/lto/CMakeLists.txt b/tools/lto/CMakeLists.txt
index 8b26ddd57e8..89160ee0239 100644
--- a/tools/lto/CMakeLists.txt
+++ b/tools/lto/CMakeLists.txt
@@ -9,10 +9,24 @@ set(SOURCES
   lto.cpp
   )
 
-if( NOT WIN32 AND LLVM_ENABLE_PIC )
+if( NOT CYGWIN AND LLVM_ENABLE_PIC )
+  if ( WIN32 )
+    # Create .def file containing a list of exports preceeded by
+    # 'EXPORTS'.  The file "lto.exports" already contains the list, so we
+    # massage it into the correct format here to create "lto.exports.def".
+    set(LTO_EXPORTS_DEF ${CMAKE_CURRENT_BINARY_DIR}/lto.exports.def)
+    file(READ "lto.exports" exports_list)
+    file(WRITE ${LTO_EXPORTS_DEF} "LIBRARY LTO\n")
+    file(APPEND ${LTO_EXPORTS_DEF} "EXPORTS\n")
+    file(APPEND ${LTO_EXPORTS_DEF} ${exports_list})
+    set(SHARED_LIB_SOURCES ${SOURCES} ${LTO_EXPORTS_DEF})
+  else()
+    set(SHARED_LIB_SOURCES ${SOURCES})
+  endif()
+
   set(bsl ${BUILD_SHARED_LIBS})
   set(BUILD_SHARED_LIBS ON)
-  add_llvm_library(LTO ${SOURCES})
+  add_llvm_library(LTO ${SHARED_LIB_SOURCES})
   set_property(TARGET LTO PROPERTY OUTPUT_NAME "LTO")
   set(BUILD_SHARED_LIBS ${bsl})
   set(LTO_STATIC_TARGET_NAME LTO_static)
@@ -25,7 +39,7 @@ if( NOT BUILD_SHARED_LIBS )
   set_property(TARGET ${LTO_STATIC_TARGET_NAME} PROPERTY OUTPUT_NAME "LTO")
 endif()
 
-if( NOT WIN32 )
+if( NOT CYGWIN )
   install(FILES ${LLVM_MAIN_INCLUDE_DIR}/llvm-c/lto.h
           DESTINATION include/llvm-c)
 endif()
-- 
2.34.1