WASMLITE (WASM TO LLVM)

该项目旨在提供编译wasm二进制到LLVM IR所需的工具，这些LLVM IR可以进一步编译为特定机器的代码。

该项目旨在使编译到wasm的语言能够利用LLVM基础设施变得更加容易。

它还允许去除昂贵的wasm运行时元素，以便在不希望完全遵守wasm规范的情况下。

最后，它是一个了解WebAssembly、LLVM以及它们如何协同工作的平台。

可能的API（非最终版本）

// Create compiler flags.
let compiler_flags = Some(CompilerOptions {
    optimization_level: 3,
    exclude_passes: vec![
        LLVMPass::InstCombine,
    ],
    runtime_ignores: vec![
        RuntimeProperty::SignatureChecks,
        RuntimeProperty::MemoryBoundsChecks,
    ],
    strategy: CompilationStrategy::Normal,
});

// Create wasm instance options.
let instance_options = Some(InstanceOptions {
    compiler_flags,
    abi: vec![ABI::LLVMMusl],
});

// JIT compile module in current process.
let (module, instance) = Runtime::instantiate(wasm_binary, imports, instance_options);

// Get the exported main function from instance.
let main = instance.get_func("main");

// Store array of items in wasm memory 0
let wasm_array = instance.set_array(&arguments);

// Call the function.
main.call(5, wasm_array);

// Create compiler flags.
let compiler_flags = Some(CompilerOptions {
    strategy: CompilationStrategy::AheadOfTime,
    ..
});

// Create wasm instance options.
let instance_options = Some(InstanceOptions { compiler_flags, .. });

// instance holds an in-memory object code of the entire wasm program.
// Possibly generates a dylib for known imports as well.
let (module, instantiate) = Runtime::instantiate(wasm_binary, imports, instance_options);

// Create executables.
let (imports_dylib, wasm_exe) = module.create_executables();

// Create compiler flags.
let compiler_flags = Some(CompilerOptions {
    strategy: CompilationStrategy::LazyCompilation,
    ..
});

// Create wasm instance options.
let instance_options = Some(InstanceOptions { compiler_flags, .. });

// Functions are not compiled until their first call.
let (module, instance) = Runtime::instantiate(wasm_binary, imports, instance_options);

// Create compiler flags.
let compiler_flags = Some(CompilerOptions {
    strategy: CompilationStrategy::REPL,
    ..
});

// Create wasm instance options.
let instance_options = Some(InstanceOptions { compiler_flags, .. });

// Lazily compiles the entire wasm instance.
let (module, instance) = Runtime::instantiate(wasm_binary, imports, instance_options);

// ???
let func = module.add_function(wasm_function_binary, instance);
let expression = module.add_expression(wasm_expression_binary, instance);

非目标

• 拥有多个后端

策略

• 单遍解析、验证和从wasm二进制到LLVM IR的代码生成

当前支持

• 解析器

  • 前缀
  • 类型
  • 导入
  • 内部内存、表
  • 元素、数据、全局变量
  • 函数体
  • 导出

• 代码生成

• 运行时

• 编译策略

• 编译标志

• 一个ABI

• 其他功能

待办事项

• wasm32 to LLVMIR to machine code

• 模糊测试

• 单元测试

• 验证（utf8 [Unicode标准11.0，第3.9节，表3-7。有效的UTF-8字节序列]和语义）

  • https://www.unicode.org/versions/Unicode11.0.0/ch03.pdf
  • https://github.webassembly.net.cn/spec/core/binary/values.html#names

• 错误消息和将错误位置指向错误位置而不是起始位置