let (file_name, start_line, start_col, end_line, end_col) = self.code_region(&span);
+ // FIXME(richkadel): Note that `const_str()` results in the creation of an `Allocation` to
+ // hold one copy of each unique filename. It looks like that `Allocation` may translate into
+ // the creation of an `@alloc` in LLVM IR that is never actually used by runtime code.
+ //
+ // Example LLVM IR:
+ //
+ // @alloc4 = private unnamed_addr constant <{ [43 x i8] }> \
+ // <{ [43 x i8] c"C:\\msys64\\home\\richkadel\\rust\\rust_basic.rs" }>, align 1
+ //
+ // Can I flag the alloc as something not to be added to codegen? Or somehow remove it before
+ // it gets added to the LLVM IR? Do we need some kind of reference counting to know it's
+ // not used by any runtime code?
+ //
+ // This question is moot if I convert the Call Terminators to Statements, I believe:
+ // https://rust-lang.zulipchat.com/#narrow/stream/233931-t-compiler.2Fmajor-changes/topic/Implement.20LLVM-compatible.20source-based.20cod.20compiler-team.23278/near/206731748
args.push(self.const_str(&file_name, inject_at));
args.push(self.const_u32(start_line, inject_at));
args.push(self.const_u32(start_col, inject_at));