斯威夫特用什么语言写的?

Well, like the title says, what language is Swift (Apple's language, not the other Swift thing) written in? More specifically, what is the compiler written in. Is it written in C (like every other language) or some other magical, unknown-til-now Super Language? Or is it some strange recursive, boot-strapped version of Swift? The web is strangely quiet on this issue.

就像题目说的，Swift是用什么语言写的?更具体地说，编译器用什么来编写。它是用C语言写的(像其他语言一样)还是其他一些神奇的、未知的、现在的超级语言?或者它是某种奇怪的递归的、启动绑定的Swift版本?奇怪的是，网络在这个问题上保持沉默。

3 个解决方案

#1

The source code has just been made available on Github, and it appears that Swift itself is primarily written in C++, and its standard library is written in Swift.

该源代码刚刚在Github上公开，看来Swift本身主要是用c++编写的，其标准库也是用Swift编写的。

For more info, see this press release from Apple, and the new Swift.org web site.

有关更多信息，请参见苹果的新闻稿和新的Swift.org网站。

#2

Swift is implemented in C. You can see an overview of one person's analysis here: https://github.com/rodionovd/SWRoute/wiki/Function-hooking-in-Swift

Swift是在c中实现的。您可以在这里看到一个人分析的概述:https://github.com/rodionovd/SWRoute/wiki/Function-hooking-in-Swift

With Swift going open-source, I imagine this question will be answered more completely at that point.

随着Swift开源，我想这个问题将在那时得到更完整的答案。

I'll include a portion below, but definitely read the whole analysis if you're interested:

我将包括下面的部分，但如果你感兴趣的话，一定要阅读整个分析:

func call_function(f : () -> Int) {
    let b = f()
}

func someFunction() -> Int {
    return 0
}

In Swift we just write call_function(someFunction). But rather than performing the call as call_function(&someFunction), Swift compiler produces the code:

在Swift中，我们只写call_function(someFunction)。但是，Swift编译器不是将调用执行为call_function(&someFunction)，而是生成代码:

struct swift_func_wrapper *wrapper =  ... /* configure wrapper for someFunction() */
struct swift_func_type_metadata *type_metadata = ... /* information about function's arguments and return type */
call_function(wrapper->trampoline, type_metadata);

A wrapper has the following structure:

包装具有以下结构:

struct swift_func_wrapper {
    uint64_t **trampoline_ptr_ptr; // = &trampoline_ptr
    uint64_t *trampoline_ptr;
    struct swift_func_object *object;
}

And what is the swift_func_object type? To create this object, Swift runtime uses a global constant named metadata[N] (which is unique for each function call that takes your func as an argument of a generic type , so for this code:

swift_func_object类型是什么?为了创建这个对象，Swift运行时使用一个名为metadata[N]的全局常量(对于每个函数调用来说，这是惟一的，它将您的func作为泛型类型的参数，所以对于这段代码:

func callf(f: () -> ()) {
    f();
}
callf(someFunction);
callf(someFunction);

two constants metadata and metadata2 will be created).

将创建两个常量元数据和元数据)。

A metadata[N]’s structure is kinda this:

元数据[N]的结构是这样的:

struct metadata {
    uint64_t *destructor_func;
    uint64_t *unknown0;
    const char type:1; // I'm not sure about this and padding,
    char padding[7];   // maybe it's just a uint64_t too...
    uint64_t *self; 
}

Initially metadataN has only two fields set: destructor_func and type. The first is a pointer to a function that will be used to deallocate all the memory for an object created with swift_allocObject(). And the latter is the object's type identifer (0x40 or '@' for functions/methods), and is (somehow) used by swift_allocObject() to create a right object for our func:

最初，metadataN只设置了两个字段:析构函数和类型。第一个是指向一个函数的指针，该函数用于释放使用swift_allocObject()创建的对象的所有内存。后者是对象的类型标识符(用于函数/方法的0x40或“@”)，它(以某种方式)被swift_allocObject()用于为我们的func创建一个正确的对象:

swift_allocObject(&metadata2->type, 0x20, 0x7);

Once the func object is created it has the following structure:

一旦创建了func对象，它具有以下结构:

struct swift_func_object {
    uint64_t *original_type_ptr;
    uint64_t *unknown0;
    uint64_t function_address;
    uint64_t *self;
}

The first field is a pointer to a corresponding metadata[N]->type value, the second one seems to be 0x4 | 1 << 24 (0x100000004) and that's indicates something maybe (dunno what). function_address is what we actually interested in for hooking, and self is (suddenly) a pointer to the self (if our object represents a plain function this field is NULL).

第一个字段是指向相应元数据的指针[N]->类型值，第二个字段似乎是0x4 | 1 < 24 (0x100000004)，这表明可能有什么(不知道什么)。function_address是我们真正感兴趣的连接，而self(突然)是指向self的指针(如果我们的对象表示一个普通函数，那么这个字段为NULL)。

#3

-9

It is built with the LLVM compiler framework included in Xcode 6, and uses the Objective-C runtime, allowing C, Objective-C, C++ and Swift code to run within a single program.

它使用Xcode 6中包含的LLVM编译器框架构建，并使用Objective-C运行时，允许C、Objective-C、c++和Swift代码在单个程序中运行。

from swift wikipedia

迅速从*

#1