Recently I was using inkwell to write a code generator with the help from LLVM.
I first parse my code into a Abstract Syntax Tree (AST), and I planned to walk through the tree to generate code.
Here is what I implemented:
I create a struct that warp Inkwell's context, builder, module inside. I have to add the explicit 'ctx lifetime because builder/module belong to context. This is limited by Inkwell library.
pub struct LLVMCodeGen<'ctx> {
pub context : Context,
pub builder : Builder<'ctx>,
pub module : Module<'ctx>
}
Later I can add a trait ToLLVM, which implement the function walk through the AST
trait ToLLVM {
fn compile(&self, visit: &mut LLVMCodeGen);
}
and I can implement each struct in AST for this trait, and inside call LLVMCodeGen's function to generate code.
However, when I really call function in LLVMCodeGen, I got some lifetime error.
impl ToLLVM for FuncDef { //FuncDef is one of struct in AST
fn compile(&self, visit: &mut LLVMCodeGen) {
let fn_type = visiti.context.i32_type().fn_type(&[], false);
visit.module.add_function("foo", fn_type, None);
}
}
However, this will give me compile error related to lifetime, with mysterious message.
84 | fn compile(&self, visit: &mut LLVMCodeGen) {
| ----------------
| |
| these two types are declared with different lifetimes...
...
96 | visit.module.add_function(&self.fun_name, fn_type, None);
| ^^^^^^^^^^^^ ...but data from `visit` flows into `visit` here
I place the link to Inwell document below:
add_function
I am not quite sure what rustc want to told me. I only got ONE, not TWO, type, that is LLVMCodeGen in my code. and what does it means that data from visit flow into visit here.
I search the error message and I got some similar post or question, but none of them can solve the issue I faced.