CODEWITHSUNDEEP
llvmllvm-ir
John Galt
John Galt

Reputation: 125

LLVM pointer as a function parameter

I am trying to pass a global variable to a function as a parameter and modify this variable inside of a function

i have IR code as follows 

@n = common global i32 0

declare i32 @readln(i32)

declare i32 @writeln(i32)

define i32 @main() {
entry:
  %n = load i32, i32* @n, align 4
  %calltmp = call i32 @readln(i32 %n)
  %n1 = load i32, i32* @n, align 4
  %calltmp2 = call i32 @writeln(i32 %n1)
  ret i32 0
}

readln defined in separate module as a C function 

int readln(int * x) {
    return  scanf("%d", x);
}

upon running i get segmentation fault 11 What am I doing wrong ?

Upvotes: 1

Views: 812

Answers (1)

Atyoum Ustainof
Atyoum Ustainof

Reputation: 394

comment is correct. inspire by this 

Builder.CreateLoad(Builder.CreateIntToPtr(Value,Type::getInt32PtrTy(TheContext)), "ptr");
Builder.CreateIntToPtr(Value,Type::getInt32PtrTy(TheContext));

Upvotes: 1

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