ObjWriter integration (#4891)

- remove CoreCLR dependence
	- fix build with the latest LLVM 5 version
	- add documentation

Signed-off-by: Petr Bred <bredpetr@gmail.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/Documentation/how-to-build-ObjectWriter.md b/Documentation/how-to-build-ObjectWriter.md
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+++ b/Documentation/how-to-build-ObjectWriter.md
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+# Build ObjectWriter library #
+
+ObjWriter is based on LLVM, so it requires recent CMake and GCC/Clang to build LLVM.
+See http://llvm.org/docs/GettingStarted.html#requirements for more details.
+
+1. Clone LLVM from official LLVM mirror github git repository:
+
+    ```
+    $ git clone -b release_50 https://github.com/llvm-mirror/llvm.git
+    ```
+
+2. Copy ObjWriter directory from CoreRT into LLVM tree
+
+    ```
+    $ cp -r CoreRT/src/Native/ObjWriter llvm/tools/
+    ```
+
+3. Apply the patch to LLVM:
+
+    ```
+    $ cd llvm
+    $ git apply tools/ObjWriter/llvm.patch
+    ```
+
+4. Configure and build LLVM with ObjWriter:
+
+    ```
+    $ mkdir build
+    $ cd build
+    $ cmake ../ -DCMAKE_BUILD_TYPE=Release -DLLVM_OPTIMIZED_TABLEGEN=1 -DHAVE_POSIX_SPAWN=0 -DLLVM_ENABLE_PIC=1 -DLLVM_BUILD_TESTS=0 -DLLVM_ENABLE_DOXYGEN=0 -DLLVM_INCLUDE_DOCS=0 -DLLVM_INCLUDE_TESTS=0
+    $ make -j10 objwriter
+    $ cd ..
+    ```
+
+* You can change the building type(CMAKE_BUILD_TYPE) to the debugging type(Debug), if necessary to debug ObjWriter.
+* Also, you can do this under chroot to building ObjWriter for other platforms.
+
+5. Get ObjWriter:
+
+   If all goes well, the build will complete in the previous step and you will get ObjWriter library as llvm/build/lib/libobjwriter.so