LLVM红外打印一个号码(LLVM IR printing a number)

LLVM红外打印一个号码(LLVM IR printing a number)

我试图打印一个数字，但是我收到错误，说我的打印功能是错误的：

define i32 @main() { entry: %d = shl i32 2, 3 %call = call i32 (i8*, ...)* @printf(i8* %d) ret i32 1 } declare i32 @printf(i8*, ...)

这是错误：

Error in compilation: /bin/this.program: llvm.ll:4:44: error: '%d' defined with type 'i8' %call = call i32 (i8*, ...)* @printf(i8* %d) ^

是否有其他打印功能修复此问题？

I'm trying to print a number, but I'm getting errors saying my print function is wrong:

define i32 @main() { entry: %d = shl i32 2, 3 %call = call i32 (i8*, ...)* @printf(i8* %d) ret i32 1 } declare i32 @printf(i8*, ...)

And here's the error:

Error in compilation: /bin/this.program: llvm.ll:4:44: error: '%d' defined with type 'i8' %call = call i32 (i8*, ...)* @printf(i8* %d) ^

Is there some other print function that fixes this?

最满意答案

LLVM IR没有隐式转换（显式转换是单独的指令）。 您的%d变量的类型为i32 ，来自第一条指令（奇怪的是错误消息是'%d' defined with type 'i8' ，可能您的示例不是您的真实代码？）。

至于printf函数，它恰好是C printf 。 你应该传递完全相同的参数 - 一个格式字符串（ i8*指向空终止的"%d" ）和一个数字。

对于字符串，你应该定义全局

@formatString = private constant [2 x i8] c"%d"

并将其作为printf第一个参数传递给：

%call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @formatString , i32 0, i32 0), i32 %d)

完整代码：

@formatString = private constant [2 x i8] c"%d" define i32 @main() { entry: %d = shl i32 2, 3 %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @formatString , i32 0, i32 0), i32 %d) ret i32 1 } declare i32 @printf(i8*, ...)

LLVM IR has no implicit casts (and explicit casts are separate instructions). Your %d variable has type i32, from the first instruction (it's odd that error message is '%d' defined with type 'i8', probably your example is not your real code?).

As for printf function, it is exactly C printf. And you should pass exactly the same arguments - a format string (i8* pointing to null terminated "%d"), and a number.

For string, you should define global

@formatString = private constant [2 x i8] c"%d"

And pass it as first argument to printf:

%call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @formatString , i32 0, i32 0), i32 %d)

Full code:

@formatString = private constant [2 x i8] c"%d" define i32 @main() { entry: %d = shl i32 2, 3 %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @formatString , i32 0, i32 0), i32 %d) ret i32 1 } declare i32 @printf(i8*, ...)