此處只是提供簡單的範例。
有時編譯 Open-source 常會遇到某些語法不清楚或錯誤時，上網路也找不著相關的教學，這時便是寫個相似的語法進行除錯，剛好這個範例提供了框架，方便進行修改和測試。
網路上有討論各個編譯時的快或慢，但在絕對的電腦下，速度不是問題；反而好除錯、好移植才是好的“自動化構建”。
構建工具只是輔助工具，我們要的是完成構建後的成果。身為軟體工程師的職責不應該花大時間去學寫構建工具，而構建工具越多 functions 和變異，越是造成進入門檻，請大家認真去思考這問題。
就想像是 Shell Script 的進化版本，提供相依性，除錯相對的直覺化。
flowchart LR
Start([Start])
subgraph make[make]
Makefile[Makefile]
end
End([End])
environment[environment variable]
style environment fill:#bbf,color:#000000,stroke:#f66,stroke-width:4px,stroke-dasharray: 5 2
Start --> make --> |make|Target -->End
make -..- environment
其實已經習慣 make 的運作，cmake 反而是多餘。
請勿在 install - DESTINATION (CMakeLists.txt) 加入 CMAKE_INSTALL_PREFIX。
flowchart LR
Start([Start])
subgraph cmake[cmake]
direction LR
CMakeLists[CMakeLists.txt]
cross[-DCMAKE_TOOLCHAIN_FILE=./cmake/build_x86.cmake]
end
End([End])
environment[environment variable]
style environment fill:#bbf,color:#000000,stroke:#f66,stroke-width:4px,stroke-dasharray: 5 2
Start --> cmake --> build_xxx --> |make|Target --> End
cmake -..- environment
meson_options.txt 要與 meson.build (第一個讀取的) 放在同一層目錄。
meson 的限制很多，如
不支援讀取 environment variable。
meson.build:1:0: ERROR: prefix value './install' must be an absolute path。
這些都對於 Cross-Compilation 是很不友善的。
另外對於一個大專案，有 make, Perl, shell script, cmake 等混合之編譯環境， 就是這麼困難修改。
有時要解決 python 版本的問題，真的很浪費時間。
flowchart LR
Start([Start])
subgraph meson[meson]
direction LR
meson_build[00 - meson.build]
meson_options[meson_options.txt]
cross[--cross-file build.meson]
subgraph meson_public[./meson_public]
meson_build_public[01 - meson.build]
end
meson_build_public-..-meson_options
style meson_options fill:#bbf,color:#000000,stroke:#f66,stroke-width:4px,stroke-dasharray: 5 2
end
End([End])
Start --> meson --> build_xxx --> |ninja|Target --> End
# meson 0.53 在 cross 時會出問題，請不要使用
# upgrade meson to 0.63
$ pip3 install meson==0.631.4. GN (Generate Ninja)
GN is a meta-build system that generates build files for Ninja.
對於老古板的我，擁有 make 和 Shellscript 就已經很滿足了，而且也很夠用。而使用 GN 也只是要處理 Open-source 附加需要的工具。
學習另一套構建工具，只會佔用開發時間，就算號稱編譯時的神速，也是九牛一毛。另外如 meson 時所提及的，在混合編譯環境下，這些構建工具反而是阻礙。所以在你還沒把現有的專案轉至這些構建工具，請三思而後行。
連安裝都很麻煩，請確定真的要用。
所有 .gn、BUILD.gn 都要用 space 來縮排。
gn 建構後，檔案無法從 output 中 copy 出來，所以沒有 ninja install。
排除官方的 guide，市面上可找到的說明或範例，少！而且不精確的地方都跟官網一樣。
$ sudo apt install -y ninja-build
$ ninja --version
1.10.0
# 自編
$ sudo apt install -y clang
$ clang --version
clang version 10.0.0-4ubuntu1
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
$ git clone https://gn.googlesource.com/gn
$ cd gn
$ python build/gen.py
$ ninja -C out
$ sudo cp out/gn /usr/bin
$ sudo cp out/gn_unittests /usr/bin
$ gn --version
2124 (e4702d740906)
flowchart LR
Start([Start])
subgraph GN[GN]
direction LR
.gn[00 - .gn]
BUILD.gn[02 - BUILD.gn]
subgraph gnX[./gnX]
direction LR
BUILD.gn-gnX[03 - BUILD.gn]
BUILDCONFIG.gn[01 - BUILDCONFIG.gn]
subgraph toolchain[./gnX/toolchain]
BUILD.gn-toolchain[03 - BUILD.gn]
end
end
subgraph cCaller[./cppTest]
BUILD.gn-cCaller[03 - BUILD.gn]
end
.gn --> BUILDCONFIG.gn --> BUILD.gn
end
End([End])
environment[environment variable]
style environment fill:#bbf,color:#000000,stroke:#f66,stroke-width:4px,stroke-dasharray: 5 2
Start --> GN --> build_xxx --> |ninja|Target --> End
GN -..- environment
flowchart TD
subgraph helloworld
helloworld.c
end
subgraph pipe2
pipe2.c
end
subgraph helloworld-123
helloworld-123.c
subgraph libhelloworld.so
helloworld_dbg.c
end
end
$ ./build-make.sh distclean
$ ./build-make.sh build
$ tree install/
install/
├── bin
│ ├── helloworld
│ ├── helloworld-123
│ └── pipe2
├── include
│ └── helloworld_dbg.h
└── lib
├── libhelloworld.so -> libhelloworld.so.0
├── libhelloworld.so.0 -> libhelloworld.so.0.0.1
└── libhelloworld.so.0.0.1
3 directories, 7 files
大致的命令如下
$ . confs/simple_x86.conf
$ (make )
$ (make install)$ ./build-cmake.sh distclean
$ ./build-cmake.sh build
$ tree install/
install/
├── bin
│ ├── helloworld
│ ├── helloworld-123
│ └── pipe2
├── include
│ └── helloworld_dbg.h
└── lib
├── libhelloworld.so -> libhelloworld.so.0
├── libhelloworld.so.0 -> libhelloworld.so.0.0.1
└── libhelloworld.so.0.0.1
3 directories, 7 files
$ ll install_Cpack/
total 80
drwxrwxr-x 3 lanka lanka 4096 十一 20 10:11 ./
drwxrwxr-x 12 lanka lanka 4096 十一 20 10:11 ../
drwxrwxr-x 3 lanka lanka 4096 十一 20 10:06 _CPack_Packages/
-rw-rw-r-- 1 lanka lanka 18578 十一 20 10:11 helloworld-123-0.0.1-Linux.deb
-rw-rw-r-- 1 lanka lanka 17856 十一 20 10:11 helloworld-123-0.0.1-Linux.tar.gz
-rw-rw-r-- 1 lanka lanka 24714 十一 20 10:11 helloworld-123-0.0.1-Linux.zip
大致的命令如下
$ . confs/simple_x86.conf
$ (mkdir -p build_xxx)
$ (cd build_xxx; cmake -DCMAKE_INSTALL_PREFIX=/work/codebase/lankahsu520-gitlab/helloworld/install -DCMAKE_TOOLCHAIN_FILE=/work/codebase/lankahsu520-gitlab/helloworld/cmake/build_x86.cmake ..)
$ (cd build_xxx; make )
$ (cd build_xxx; make install)
$ (cd build_xxx; make package)
$ ./build-meson.sh distclean
$ ./build-meson.sh build
$ tree install/
install/
├── bin
│ ├── helloworld
│ ├── helloworld-123
│ └── pipe2
├── include
│ └── helloworld_dbg.h
└── lib
├── libhelloworld_dbg.so -> libhelloworld_dbg.so.0
├── libhelloworld_dbg.so.0 -> libhelloworld_dbg.so.0.0.1
└── libhelloworld_dbg.so.0.0.1
3 directories, 7 files
大致的命令如下
$ . confs/simple_x86.conf
$ (mkdir -p build_xxx)
$ (cp -vf /work/codebase/lankahsu520-gitlab/helloworld/meson_public/meson_options.txt /work/codebase/lankahsu520-gitlab/helloworld/meson_options.txt)
$ (cp -vf /work/codebase/lankahsu520/makeXcmakeXmesonXgn/meson_public/build_x86.meson /work/codebase/lankahsu520/makeXcmakeXmesonXgn/build.meson)
$ (meson build_xxx --prefix /work/codebase/lankahsu520/helloworld/install --cross-file /work/codebase/lankahsu520/helloworld/build.meson)
$ (ninja -C build_xxx)
$ (ninja -C build_xxx install)
$ ./build-gn.sh distclean
$ ./build-gn.sh build
$ tree install/
install/
├── bin
│ ├── cppCaller
│ ├── cppHelloWorldv2
│ ├── helloworld
│ ├── helloworld-123
│ └── pipe2
├── include
│ └── helloworld_dbg.h
└── lib
└── libhelloworld.so
3 directories, 7 file
大致的命令如下
$ . confs/simple_x86.conf
$ (mkdir -p build_xxx)
$ (gn gen -C build_xxx)
$ (ninja -v -C build_xxx)
$ (mkdir -p /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/bin; cp -avr build_xxx/bin/* /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/bin)
$ (mkdir -p /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/include; cp -avr build_xxx/include/* /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/include)
$ (mkdir -p /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/lib; cp -avr build_xxx/lib/* /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/lib)
Please install aarch64-buildroot-linux-gnu_sdk-buildroot.tar.gz into your system.
You can check helper_Buildroot-RaspberryPi3.md - Buildroot Raspberry Pi 3 helper,
2.2. To Generate Toolchain.
$ ./build-make.sh distclean
$ ./build-make.sh build aarch64
$ tree install/
install/
├── bin
│ ├── helloworld
│ ├── helloworld-123
│ └── pipe2
├── include
│ └── helloworld_dbg.h
└── lib
├── libhelloworld.so -> libhelloworld.so.0
├── libhelloworld.so.0 -> libhelloworld.so.0.0.1
└── libhelloworld.so.0.0.1
3 directories, 7 files
$ file install/bin/helloworld
install/bin/helloworld: ELF 64-bit LSB shared object, ARM aarch64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-aarch64.so.1, for GNU/Linux 5.10.0, stripped
大致的命令如下
$ . confs/simple-aarch64.conf
$ (make )
$ (make install)$ ./build-cmake.sh distclean
$ ./build-cmake.sh build aarch64
$ tree install/
install/
├── bin
│ ├── helloworld
│ ├── helloworld-123
│ └── pipe2
├── include
│ └── helloworld_dbg.h
└── lib
├── libhelloworld.so -> libhelloworld.so.0
├── libhelloworld.so.0 -> libhelloworld.so.0.0.1
└── libhelloworld.so.0.0.1
3 directories, 7 files
$ ll install_Cpack/
total 68
drwxrwxr-x 3 lanka lanka 4096 十一 20 10:22 ./
drwxrwxr-x 12 lanka lanka 4096 十一 20 10:22 ../
drwxrwxr-x 3 lanka lanka 4096 十一 20 10:22 _CPack_Packages/
-rw-rw-r-- 1 lanka lanka 16336 十一 20 10:22 helloworld-123-0.0.1-Linux.deb
-rw-rw-r-- 1 lanka lanka 15677 十一 20 10:22 helloworld-123-0.0.1-Linux.tar.gz
-rw-rw-r-- 1 lanka lanka 21736 十一 20 10:22 helloworld-123-0.0.1-Linux.zip
$ file install/bin/helloworld
install/bin/helloworld: ELF 64-bit LSB shared object, ARM aarch64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-aarch64.so.1, for GNU/Linux 5.10.0, with debug_info, not stripped
大致的命令如下
$ . confs/simple-aarch64.conf
$ (mkdir -p build_xxx)
$ (cd build_xxx; cmake -DCMAKE_INSTALL_PREFIX=/work/codebase/lankahsu520/makeXcmakeXmesonXgn/install -DCMAKE_TOOLCHAIN_FILE=/work/codebase/lankahsu520/makeXcmakeXmesonXgn/cmake/build_aarch64.cmake ..)
$ (cd build_xxx; make )
$ (cd build_xxx; make install)
$ (cd build_xxx; make package)
$ ./build-meson.sh distclean
$ ./build-meson.sh build aarch64
$ tree install/
install/
├── bin
│ ├── helloworld
│ ├── helloworld-123
│ └── pipe2
├── include
│ └── helloworld_dbg.h
└── lib
├── libhelloworld_dbg.so -> libhelloworld_dbg.so.0
├── libhelloworld_dbg.so.0 -> libhelloworld_dbg.so.0.0.1
└── libhelloworld_dbg.so.0.0.1
3 directories, 7 files
$ file install/bin/helloworld
install/bin/helloworld: ELF 64-bit LSB shared object, ARM aarch64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-aarch64.so.1, for GNU/Linux 5.10.0, with debug_info, not stripped
大致的命令如下
$ . confs/simple_aarch64.conf
$ (mkdir -p build_xxx)
$ (cp -vf /work/codebase/lankahsu520/makeXcmakeXmesonXgn/meson_public/meson_options.txt /work/codebase/lankahsu520/makeXcmakeXmesonXgn/meson_options.txt)
$ (cp -vf /work/codebase/lankahsu520/makeXcmakeXmesonXgn/meson_public/build_aarch64.meson /work/codebase/lankahsu520/makeXcmakeXmesonXgn/build.meson)
$ (meson build_xxx --prefix /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install --cross-file /work/codebase/lankahsu520/makeXcmakeXmesonXgn/build.meson)
$ (ninja -C build_xxx)
$ (ninja -C build_xxx install)
$ ./build-gn.sh distclean
$ ./build-gn.sh build aarch64
$ tree install/
install
├── bin
│ ├── cppCaller
│ ├── cppHelloWorldv2
│ ├── helloworld
│ ├── helloworld-123
│ └── pipe2
├── include
│ └── helloworld_dbg.h
└── lib
└── libhelloworld.so
3 directories, 7 files
$ file install/bin/helloworld
install/bin/helloworld: ELF 64-bit LSB shared object, ARM aarch64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-aarch64.so.1, for GNU/Linux 5.10.0, with debug_info, not stripped
大致的命令如下
$ . confs/simple_aarch64.conf
$ (mkdir -p build_xxx)
$ (gn gen -C build_xxx)
$ (ninja -v -C build_xxx)
$ (mkdir -p /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/bin; cp -avr build_xxx/bin/* /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/bin)
$ (mkdir -p /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/include; cp -avr build_xxx/include/* /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/include)
$ (mkdir -p /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/lib; cp -avr build_xxx/lib/* /work/codebase/lankahsu520/makeXcmakeXmesonXgn/install/lib)
只要參數換成 i486，其它操作相同。
雖然 x86_64 能向下相容，gcc -m32也能編譯出 32-Bit，但還是特別把 i486 當成 Cross。因為32-Bit 和 64-Bit 有很大的差異，另外對應的作業系統也相當的老舊，那怕那一天拿到一台10年前的電腦，也能有所應付。
$ ./build-make.sh build i486$ ./build-cmake.sh build i486$ ./build-meson.sh build aarch64$ ./build-gn.sh build aarch64Run an example and read it.
I.3. GN
參考的範例很少，官網
這是很失敗的 guide，短短一篇文章，在對 gn 還沒有一定的熟悉下，是完全不知其所道。
舉例，如在章節 Passing build arguments，
gn args out/my_build照著指示操作，新增了 args - is_debug，但是呢 ? 怎麼用 ? 而且 "gn args --list" 也沒有相應的資料，總之從一開始到放棄只要10分鐘。
這邊告訴各位，沒有在 BUILDCONFIG.gn 先宣告 is_debug，之後你在編譯目錄 out/my_build 修改也是沒用的。
B. GN Reference
$ objdump -f build_xxx/libhelloworld.so
build_xxx/libhelloworld.so: file format elf64-x86-64
architecture: i386:x86-64, flags 0x00000150:
HAS_SYMS, DYNAMIC, D_PAGED
start address 0x0000000000001040
$ objdump -f build_xxx/libhelloworld.a
In archive build_xxx/libhelloworld.a:
helloworld_dbg.c.o: file format elf64-x86-64
architecture: i386:x86-64, flags 0x00000011:
HAS_RELOC, HAS_SYMS
start address 0x0000000000000000
$ file build_xxx/libhelloworld.so.0.0.1
build_xxx/libhelloworld.so.0.0.1: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=a40027cd19af73a2a7e8a278b3f060dae18a594a, with debug_info, not stripped
$ file build_xxx/libhelloworld.a
build_xxx/libhelloworld.a: current ar archive
II.1. The variable "is_component_build" was set as a build argument but never appeared in a declare_args() block in any buildfile.
WARNING at build arg file (use "gn args <out_dir>" to edit):2:22: Build argument has no effect. is_component_build = true ^--- The variable "is_component_build" was set as a build argument but never appeared in a declare_args() block in any buildfile.
To view all possible args, run "gn args --list <out_dir>"
The build continued as if that argument was unspecified.
建議在 gnX/BUILDCONFIG.gn 新增
declare_args()
{
is_component_build = true
is_debug = false
}II.2. WARNING: Running the setup command as meson [options] instead of meson setup [options] is ambiguous and deprecated.
這就是為什麼不是很喜歡用 meson；才出市沒多久，就要一直追著版本修改。
$ mkdir build_xxx
# 原本
$ meson build_xxx
# 換成
$ meson setup build_xxx
$ meson setup --reconfigure build_xxxCreated and designed by Lanka Hsu.
makeXcmakeXmesonXgn is available under the BSD-3-Clause license. See the LICENSE file for more info.