Building and hacking LDC on Windows using MSVC

LDC on Windows is work in progress. This page documents how to build, test and hack LDC2 on Windows x64.

Pre-built LDC

If you just want to download the very latest pre-built LDC for Win64, head over to Latest pre-built LDC for Win64.

Building LDC

Required software

• Windows x64, of course!
• Visual Studio (e.g. VS Community 2015)
• git 1.8+ (I use PortableGit)
• Python 2.7.x or Python 3.3.x (I use Portable Python)
• CMake 2.8+
• Ninja, a neat little and fast build system
• Curl library (just use a precompiled one)
  • Put 64-bit curl.lib in a LIB/LIBPATH directory (e.g., C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\lib\amd64)...
  • ... and 64-bit libcurl.dll in a PATH directory (e.g., C:\LDC\LDC-x64\bin).

Shell environment

I use a little batch file to set up my LDC build environment. It's located in the root of my LDC environment: C:\LDC\shell.cmd. It sets up the PATH environment variable (I've installed the portable tools into C:\LDC\Tools) and then spawns a new VS 2015 x64 Native Tools Command Prompt with a below-normal process priority, so that my system stays responsive while building. I use a shortcut on my desktop to this batch file. Please adjust it to your needs (and note that %~dp0 is the directory containing the script, i.e., C:\LDC\).

@echo off
set PATH=%~dp0LDC-x64\bin;%~dp0LLVM-x64\bin;%~dp0Tools\Ninja 1.6.0;%~dp0Tools\make-3.81\bin;%~dp0Tools\PortableGit-1.8.1.2-preview20130201\bin;%~dp0Tools\cmake-3.3.0-win32-x86\bin;%~dp0Tools\Portable Python 2.7.5.1\App;%PATH%
if not exist "%TERM%" set TERM=msys
start /belownormal %comspec% /k "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" amd64

Open a shell by executing the batch file.

• Running cl should display the banner from the MS compiler.
• Running git --version should display the banner from git.
• Running python --version should display the banner from python.
• Running cmake --version should display the banner from cmake.
• Running ninja --version should display the ninja version.

Build LLVM

To build LLVM from the command line, just execute the following steps (from C:\LDC):

• Get the source: git clone http://llvm.org/git/llvm.git llvm
• Check out the LLVM 3.7 branch: git checkout release_37
• Create a build directory: md build-llvm-x64
• Change into it: cd build-llvm-x64

• Use a command like this (in one line) to create the Ninja build files:

  cmake -G Ninja -DCMAKE_INSTALL_PREFIX="C:\LDC\LLVM-x64" -DCMAKE_BUILD_TYPE="RelWithDebInfo"
        -DPYTHON_EXECUTABLE="C:\LDC\Tools\Portable Python 2.7.5.1\App\python.exe"
        -DLLVM_TARGETS_TO_BUILD="X86" -DLLVM_INCLUDE_TESTS=OFF -DLLVM_INCLUDE_EXAMPLES=OFF
        -DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_APPEND_VC_REV=ON ..\llvm

  Omit the CMAKE_BUILD_TYPE definition to build a debug version. The LLVM page on CMake documents other variables you can change. The most common is to add more targets. E.g. to build a target for ARM you change the targets to build to -DLLVM_TARGETS_TO_BUILD="X86;ARM".

• Build LLVM: ninja
• Install it: ninja install

Build libconfig

• cd C:\LDC
• git clone https://github.com/hyperrealm/libconfig.git libconfig
• cd libconfig
• Build the static C library: msbuild lib\libconfig.vcxproj /t:Rebuild /p:Configuration=ReleaseStatic /p:Platform=x64
  • Use configuration DebugStatic for debug LDC builds to ensure we link against the same runtime library

Build LDC

• cd C:\LDC
• git clone --recursive git://github.com/ldc-developers/ldc.git ldc
• md build-ldc-x64
• cd build-ldc-x64

• Use a command like this (in one line):

  cmake -G Ninja -DCMAKE_INSTALL_PREFIX="C:\LDC\LDC-x64" -DCMAKE_BUILD_TYPE="RelWithDebInfo"
        -DLLVM_ROOT_DIR="C:/LDC/LLVM-x64" -DLIBCONFIG_INCLUDE_DIR="C:/LDC/libconfig/lib"
        -DLIBCONFIG_LIBRARY="C:/LDC/libconfig/lib/x64/ReleaseStatic/libconfig.lib" ..\ldc

• Build LDC and the runtimes: ninja
• If you want to install it: ninja install

Tests

Running the IR codegen tests

• You'll need to have lit installed for Python.
• cd C:\LDC\build-ldc-x64\tests\ir
• python runlit.py -v .

Running the runtime unit tests

• cd C:\LDC\build-ldc-x64
• Build the unit tests: ninja druntime-ldc-unittest druntime-ldc-unittest-debug phobos2-ldc-unittest phobos2-ldc-unittest-debug
• Run the tests, excluding the dmd-testsuite ones: ctest -E dmd-testsuite

For troubleshooting be sure to examine the file C:\LDC\build-ldc-x64\Testing\Temporary\LastTest.log.

Running the dmd-testsuite tests

dmd-testsuite requires a minimalistic GNU environment. bash is shipped with git. Additionally, we need GNU make and reasonably recent GNU diffutils and coreutils:

• Download GNU make for Windows: binary + dependencies
• Download GNU diffutils for Windows: binaries (same dependencies as make)
• Download GNU coreutils for Windows: binaries (same dependencies as make)
• Extract all 4 ZIP archives into a common root folder, e.g., C:\LDC\Tools\make
• Edit your shell batch script and add the bin subdirectory to your PATH, e.g., set PATH=%~dp0Tools\make\bin;%PATH%
  • Make sure that directory preceeds the git bin directory in the PATH environment variable, so that the more recent executables in C:\LDC\Tools\make\bin are preferred over the (in my case, ancient) versions shipped with git.
• Spawn a new shell and make sure make --version prints its banner.

Now that we have extended our LDC build environment, we're able to run the dmd-testsuite tests. I prefer to run them manually, outside of ctest.

• cd C:\LDC\build-ldc-x64
• If you want to reset the results, delete the folder: rmdir /S dmd-testsuite(-debug)
• Get the command line from C:\LDC\build-ldc-x64\tests\d2\CTestTestfile.cmake (e.g., "make" "-k" "-C" "C:/LDC/ldc/tests/d2/dmd-testsuite" "RESULTS_DIR=C:/LDC/build-ldc-x64/dmd-testsuite-debug" ... "quick")
  • You may want to redirect stdout and stderr to a log file by appending something like  > dmd-testsuite.log 2>&1
• Start the tests.
• Run the tests a second time without resetting the results to get a list of the failures and disabled tests.

Developing/debugging LDC/LLVM with Visual Studio

• cd C:\LDC
• md vs-ldc-x64
• cd vs-ldc-x64
• Use the cmake command from the Build LDC section, but use the VS generator instead of Ninja this time: cmake -G "Visual Studio 14 Win64" ...
• This creates the VS solution C:\LDC\vs-ldc-x64\ldc.sln.

A Visual Studio solution for LLVM can be created the same way.

Known bugs/limitations

• Structured Exception Handling is only available for LLVM 3.7. Support in ldc.eh.win64 has still alpha quality and is known to crash your application under certain circumstances. LLVM is getting native support for MSVCRT exceptions, so we'll wait for that.
• Visual Studio 2015 is greatly encouraged due to improved C99 support.
• State as of September 26th 2015: 4 issues left in runtime unittests and dmd-testsuite

Example

The simple D program hello.d

import std.stdio;

int main()
{
    writefln("Hello LDC2");
    return 0;
}

can be compiled and linked with the commands:

ldc2 -c hello.d
link hello2.obj phobos-ldc.lib shell32.lib

or simply with: ldc2 hello.d

The resulting hello.exe produces the expected output.

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Windows MSVC