25cd982263
When building statically against LLVM, LLD is also included now. When included, the built in wasm-ld will automatically be used instead of the external command. There is also support for linking ELF files but because lld does not fully support armv6m this is not yet enabled (it produces a warning).
107 строки
4,3 КиБ
Markdown
107 строки
4,3 КиБ
Markdown
# Building TinyGo
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TinyGo depends on LLVM and libclang, which are both big C++ libraries. It can
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also optionally use a built-in lld to ease cross compiling. There are two ways
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these can be linked: dynamically and statically. The default is dynamic linking
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because it is fast and works almost out of the box on Debian-based systems with
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the right libraries installed.
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This guide describes how to statically link TinyGo against LLVM, libclang and
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lld so that the binary can be easily moved between systems.
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## Dependencies
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LLVM, Clang and LLD are quite light on dependencies, requiring only standard
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build tools to be built. Go is of course necessary to build TinyGo itself.
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* Go (1.11+)
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* [dep](https://golang.github.io/dep/)
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* Standard build tools (gcc/clang)
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* git or subversion
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* CMake
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* [Ninja](https://ninja-build.org/) or make (preferably Ninja)
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The rest of this guide assumes you're running Linux, but it should be equivalent
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on a different system like Mac.
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## Download the source
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The first step is to get the source code. Place it in some directory, assuming
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`$HOME/src` here, but you can pick a different one of course:
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git clone -b release_70 https://github.com/llvm-mirror/llvm.git $HOME/src/llvm
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git clone -b release_70 https://github.com/llvm-mirror/clang.git $HOME/src/llvm/tools/clang
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git clone -b release_70 https://github.com/llvm-mirror/lld.git $HOME/src/llvm/tools/lld
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go get -d github.com/tinygo-org/tinygo
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cd $HOME/go/src/github.com/tinygo-org/tinygo
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dep ensure -vendor-only # download dependencies
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Note that Clang and LLD must be placed inside the tools subdirectory of LLVM to
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be automatically built with the rest of the system.
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## Build LLVM, Clang, LLD
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Building LLVM is quite easy compared to some other software packages. However,
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the default configuration is _not_ optimized for distribution. It is optimized
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for development, meaning that binaries produce accurate error messages at the
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cost of huge binaries and slow compiles.
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Before configuring, you may want to set the following environment variables to
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speed up the build. Most Linux distributions ship with GCC as the default
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compiler, but Clang is significantly faster and uses much less memory while
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producing binaries that are about as fast.
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export CC=clang
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export CXX=clang++
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Make a build directory. LLVM requires out-of-tree builds:
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mkdir $HOME/src/llvm-build
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cd $HOME/src/llvm-build
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Configure LLVM with CMake:
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cmake -G Ninja ../llvm "-DLLVM_TARGETS_TO_BUILD=X86;ARM;AArch64" "-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=AVR;WebAssembly" -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_ASSERTIONS=OFF -DLIBCLANG_BUILD_STATIC=ON
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You can also choose a different build system than Ninja, but Ninja is fast.
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There are various options you can tune here, but the options given above are
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preferable for releases. Here is what they do:
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* `LLVM_TARGETS_TO_BUILD` and `LLVM_EXPERIMENTAL_TARGETS_TO_BUILD`: the
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targets that are natively supported by the LLVM code generators. The targets
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listed here are the ones supported by TinyGo. Note that LLVM is a cross
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compiler by default, unlike some other compilers.
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* `CMAKE_BUILD_TYPE`: the default is Debug, which produces large inefficient
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binaries that are easy to debug. We want small and fast binaries.
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* `LLVM_ENABLE_ASSERTIONS`: the default is ON, which greatly slows down LLVM
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and is only really useful during development. Disable them here.
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* `LIBCLANG_BUILD_STATIC`: unlike LLVM, libclang is built as a shared library
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by default. We want a static library for easy distribution.
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Now build it:
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ninja # or make, if you choose make in the previous step
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This can take over an hour depending on the speed of your system.
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## Build TinyGo
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Now that you have a working version of LLVM, build TinyGo using it. You need to
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specify the directories to the LLVM build directory and to the Clang and LLD source.
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cd $HOME/go/src/github.com/tinygo-org/tinygo
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make static LLVM_BUILDDIR=$HOME/src/llvm-build CLANG_SRC=$HOME/src/llvm/tools/clang LLD_SRC=$HOME/src/llvm/tools/lld
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## Verify TinyGo
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Try running TinyGo:
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./build/tinygo help
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Also, make sure the `tinygo` binary really is statically linked. Check this
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using `ldd` (not to be confused with `lld`):
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ldd ./build/tinygo
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The result should not contain libclang or libLLVM.
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