137 lines
4.2 KiB
Markdown
137 lines
4.2 KiB
Markdown
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# Prepare WASM building environments
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WASI-SDK version 7.0+ is the major tool supported by WAMR for building WASM applications. There are some other WASM compilers such as the standard clang compiler and Emscripten might also work [here](./other_wasm_compilers.md).
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Install WASI SDK: Download the [wasi-sdk](https://github.com/CraneStation/wasi-sdk/releases) and extract the archive to default path `/opt/wasi-sdk`
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Build WASM applications
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=========================
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You can write a simple ```test.c``` as the first sample.
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``` C
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#include <stdio.h>
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#include <stdlib.h>
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int main(int argc, char **argv)
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{
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char *buf;
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printf("Hello world!\n");
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buf = malloc(1024);
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if (!buf) {
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printf("malloc buf failed\n");
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return -1;
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}
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printf("buf ptr: %p\n", buf);
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sprintf(buf, "%s", "1234\n");
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printf("buf: %s", buf);
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free(buf);
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return 0;
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}
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```
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To build the source file to WASM bytecode, input following command:
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``` Bash
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/opt/wasi-sdk/bin/clang test.c -o test.wasm
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```
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# Build a project with cmake
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If you have complex WASM application project which contains dozens of source files, you can consider using cmake for project building.
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You can cross compile your project by using the toolchain provided by WAMR.
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We can generate a `CMakeLists.txt` file for `test.c`:
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``` cmake
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cmake_minimum_required (VERSION 3.5)
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project(hello_world)
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set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS},--export=main")
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add_executable(hello_world test.c)
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```
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It is simple to build this project by cmake:
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``` Bash
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mkdir build && cd build
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cmake .. -DCMAKE_TOOLCHAIN_FILE=$WAMR_ROOT/wamr-sdk/app/wamr_toolchain.cmake
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make
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```
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You will get ```hello_world``` which is the WASM app binary.
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> Note: If you have already built a SDK profile, then the **DCMAKE_TOOLCHAIN_FILE** should be changed into `$WAMR_ROOT/wamr-sdk/out/${PROFILE}/app-sdk/wamr_toolchain.cmake`
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# Compile WASM to AoT module
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Please ensure the wamrc was already generated and available in your shell PATH. Then we can use wamrc to compile WASM app binary to WAMR AoT binary.
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``` Bash
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wamrc -o test.aot test.wasm
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```
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wamrc supports a number of compilation options through the command line arguments:
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``` Bash
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wamrc --help
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Usage: wamrc [options] -o output_file wasm_file
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--target=<arch-name> Set the target arch, which has the general format: <arch><sub>
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<arch> = x86_64, i386, arm, thumb, mips.
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Default is host arch, e.g. x86_64
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<sub> = for ex. on arm or thumb: v5, v6m, v7a, v7m, etc.
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Use --target=help to list supported targets
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--target-abi=<abi> Set the target ABI, e.g. gnu, eabi, gnueabihf, etc. (default: gnu)
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Use --target-abi=help to list all the ABI supported
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--cpu=<cpu> Set the target CPU (default: host CPU, e.g. skylake)
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Use --cpu=help to list all the CPU supported
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--cpu-features=<features> Enable or disable the CPU features
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Use +feature to enable a feature, or -feature to disable it
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For example, --cpu-features=+feature1,-feature2
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Use --cpu-features=+help to list all the features supported
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--opt-level=n Set the optimization level (0 to 3, default: 3)
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--format=<format> Specifies the format of the output file
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The format supported:
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aot (default) AoT file
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object Native object file
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llvmir-unopt Unoptimized LLVM IR
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llvmir-opt Optimized LLVM IR
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Examples: wamrc -o test.aot test.wasm
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wamrc --target=i386 -o test.aot test.wasm
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wamrc --target=i386 --format=object -o test.o test.wasm
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```
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Run WASM app in WAMR mini product build
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========================
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Run the test.wasm or test.aot with WAMR mini product build:
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``` Bash
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./iwasm test.wasm or
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./iwasm test.aot
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```
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You will get the following output:
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```
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Hello world!
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buf ptr: 0x400002b0
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buf: 1234
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```
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If you would like to run the test app on Zephyr, we have embedded a test sample into its OS image. You will need to execute:
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```
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ninja run
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```
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