https://github.com/ejunjsh/kaleidoscope

My First Language Frontend with LLVM Tutorial
https://github.com/ejunjsh/kaleidoscope

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My First Language Frontend with LLVM Tutorial

• Host: GitHub
• URL: https://github.com/ejunjsh/kaleidoscope
• Owner: ejunjsh
• Created: 2022-08-12T03:01:32.000Z (about 2 years ago)
• Default Branch: main
• Last Pushed: 2022-10-05T06:23:21.000Z (about 2 years ago)
• Last Synced: 2023-03-05T02:28:17.605Z (over 1 year ago)
• Language: C++
• Size: 88.9 KB
• Stars: 3
• Watchers: 1
• Forks: 0
• Open Issues: 3
• Metadata Files:
  • Readme: README.md

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README

        
# kaleidoscope

My First Language Frontend with LLVM Tutorial

## 前提

根据下面链接安装llvm

https://llvm.org/docs/CMake.html#quick-start 

## 编译

````

$ mkdir build

$ cd build

$ cmake -DCMAKE_BUILD_TYPE=Release -DLLVM_DIR={path to llvm config cmake} .. && cmake --build .

# {path to llvm config cmake} 是llvm的安装路径下LLVMConfig.cmake所在的目录，

# 一般你llvm是安装到标准的目录，cmake在查找包能找到话，可以不加-DLLVM_DIR 这个选项

````

这时候就会生成一个可执行文件kaleidocscope,运行它

````

$ ./kaleidocscope

````

## 语法

只有一个类型，浮点类型

### 支持函数定义：

````

ready> def add(x y) x+y;

ready> add(1,3);

ready> Evaluated to 4.000000

````

### 支持外部函数：

````

ready> extern sin(x);

ready> sin(1.0);

ready> Evaluated to 0.841471

````

### 支持条件判断

````

ready> def fib(x)                          

        if x < 3 then

            1

        else

            fib(x-1)+fib(x-2);

ready> fib(4);  

ready> Evaluated to 3.000000

````

### 支持循环

````

extern putchard(char);

def printstar(n)

  for i = 1, i < n, 1.0 in

    putchard(42);  # ascii 42 = '*'

# print 100 '*' characters

printstar(100);

````

### 支持操作符重载

#### 二元操作符重载

下面代码实现了对`:`的重载，实现了类似多表达式的（多条语句）语法

````

ready> extern printd(x);

ready> def binary : 1 (x y) 0;  # Low-precedence operator that ignores operands.

ready> printd(123) : printd(456) : printd(789);

123.000000

456.000000

789.000000

Evaluated to 0.000000

````

#### 一元操作符重载

````

ready> def unary!(v)

  if v then

    0

  else

    1;

ready> !1;

ready> Evaluated to 0.000000

ready> !0;

ready> Evaluated to 1.000000

````

### 支持定义变量

````

# Define ':' for sequencing: as a low-precedence operator that ignores operands

# and just returns the RHS.

def binary : 1 (x y) y;

def fibi(x)

  var a = 1, b = 1, c in

  (for i = 3, i < x in

     c = a + b :

     a = b :

     b = c) :

  b;

# Call it.

fibi(10);

# Evaluated to 55.000000

````

## 参考

https://llvm.org/docs/tutorial/MyFirstLanguageFrontend/index.html