[dpdk-dev] [PATCH v2 7/7] doc: guide for Windows build using MinGW-w64

[Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>]

Instructions for different toolchains presented as options on the
corresponging steps of the guide, so that common parts may be reused.

Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
---
 doc/guides/windows_gsg/build_dpdk.rst | 65 +++++++++++++++++++++++----
 1 file changed, 56 insertions(+), 9 deletions(-)

diff --git a/doc/guides/windows_gsg/build_dpdk.rst b/doc/guides/windows_gsg/build_dpdk.rst
index 6711e07e2..6d093d235 100644
--- a/doc/guides/windows_gsg/build_dpdk.rst
+++ b/doc/guides/windows_gsg/build_dpdk.rst
@@ -7,15 +7,22 @@ Compiling the DPDK Target from Source
 System Requirements
 -------------------
 
-The DPDK and its applications require the Clang-LLVM C compiler
-and Microsoft MSVC linker.
+Building the DPDK and its applications requires one of the following
+environments:
+
+* The Clang-LLVM C compiler and Microsoft MSVC linker.
+* The MinGW-w64 toolchain (either native or cross).
+
 The Meson Build system is used to prepare the sources for compilation
 with the Ninja backend.
 The installation of these tools is covered in this section.
 
 
+Option 1. Clang-LLVM C Compiler and Microsoft MSVC Linker
+---------------------------------------------------------
+
 Install the Compiler
---------------------
+~~~~~~~~~~~~~~~~~~~~
 
 Download and install the clang compiler from
 `LLVM website <http://releases.llvm.org/download.html>`_.
@@ -25,7 +32,7 @@ For example, Clang-LLVM direct download link::
 
 
 Install the Linker
-------------------
+~~~~~~~~~~~~~~~~~~
 
 Download and install the Build Tools for Visual Studio to link and build the
 files on windows,
@@ -34,6 +41,15 @@ When installing build tools, select the "Visual C++ build tools" option
 and ensure the Windows SDK is selected.
 
 
+Option 2. MinGW-w64 Toolchain
+-----------------------------
+
+Obtain the latest version from
+`MinGW-w64 website <http://mingw-w64.org/doku.php/download>`_.
+On Windows, install to a folder without spaces in its name, like ``C:\MinGW``.
+This path is assumed for the rest of this guide.
+
+
 Install the Build System
 ------------------------
 
@@ -43,6 +59,14 @@ A good option to choose is the MSI installer for both meson and ninja together::
 
 	http://mesonbuild.com/Getting-meson.html#installing-meson-and-ninja-with-the-msi-installer%22
 
+.. warning::
+
+    Meson 0.53 has `issue #6431 <https://github.com/mesonbuild/meson/issues/6431>`_
+    that prevents cross-compilation and another linker issue with Clang
+    (`workaround patch <https://github.com/mesonbuild/meson/pull/6483>`_).
+    Meson 0.47.1 is recommended, Meson 0.52 can also be used if new features
+    are required.
+
 Install the Backend
 -------------------
 
@@ -56,23 +80,41 @@ Build the code
 The build environment is setup to build the EAL and the helloworld example by
 default.
 
-Using the ninja backend
-~~~~~~~~~~~~~~~~~~~~~~~~
+Option 1. Native Build on Windows
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Specifying the compiler might be required to complete the meson command.
+When using Clang-LLVM, specifying the compiler might be required to complete
+the meson command:
 
 .. code-block:: console
 
     set CC=clang
 
+When using MinGW-w64, it is sufficient to have toolchain executables in PATH:
+
+.. code-block:: console
+
+    set PATH=C:\MinGW\mingw64\bin;%PATH%
+
 To compile the examples, the flag ``-Dexamples`` is required.
 
 .. code-block:: console
 
     cd C:\Users\me\dpdk
     meson -Dexamples=helloworld build
-    cd build
-    ninja
+    ninja -C build
+
+Option 2. Cross-Compile with MinGW-w64
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The cross-file option must be specified for Meson.
+Depending on the distribution, paths in this file may need adjustments.
+
+.. code-block:: console
+
+    meson --cross-file config/x86/meson_mingw.txt -Dexamples=helloworld build
+    ninja -C build
+
 
 Run the helloworld example
 ==========================
@@ -87,3 +129,8 @@ Navigate to the examples in the build directory and run `dpdk-helloworld.exe`.
     hello from core 3
     hello from core 0
     hello from core 2
+
+Note for MinGW-w64: applications are linked to ``libwinpthread-1.dll``
+by default. To run the example, either add toolchain executables directory
+to the PATH or copy the library to the working directory.
+Alternatively, static linking may be used (mind the LGPLv2.1 license).
-- 
2.25.0