Nested Functions?

IR & Optimizations
1

Hi friend,
Good day,

Does anyone know how to implement “Nested Function” in “LLVM IR”?

Nested functions are functions that have access to locals and params in outer function. For example consider C like bellow code:

void Func()
{

int X;
int AddToX(int y)
{

    return X+y;

}
X=2;
std::cout <<  AddToX(5);

}

2

closures are a similar concept. There is no native support for them. You have to build your nested functions on top of LLMV IR.

1 Like
3

You should be able to “slap on” some leading text so the scoped symbols are not visible external to the scoping boundary (conceptually not much different than labels within a function.

decorating your function::

void Func()
{
int X;
int Func_BB3_AddToX(int y)
{
return X+y;
}
X=2;
std::cout << Func_BB3_AddToX(5);
}

You may need to slap on some basic block information in case someone uses the same inner function names in nested scopes.