| use rustc_hir::LangItem; |
| use rustc_middle::mir; |
| use rustc_middle::query::TyCtxtAt; |
| use rustc_middle::ty; |
| use rustc_middle::ty::layout::LayoutOf; |
| use rustc_span::symbol::Symbol; |
| use rustc_type_ir::Mutability; |
| |
| use crate::const_eval::{mk_eval_cx, CanAccessStatics, CompileTimeEvalContext}; |
| use crate::interpret::*; |
| |
| /// Allocate a `const core::panic::Location` with the provided filename and line/column numbers. |
| fn alloc_caller_location<'mir, 'tcx>( |
| ecx: &mut CompileTimeEvalContext<'mir, 'tcx>, |
| filename: Symbol, |
| line: u32, |
| col: u32, |
| ) -> MPlaceTy<'tcx> { |
| let loc_details = ecx.tcx.sess.opts.unstable_opts.location_detail; |
| // This can fail if rustc runs out of memory right here. Trying to emit an error would be |
| // pointless, since that would require allocating more memory than these short strings. |
| let file = if loc_details.file { |
| ecx.allocate_str(filename.as_str(), MemoryKind::CallerLocation, Mutability::Not).unwrap() |
| } else { |
| // FIXME: This creates a new allocation each time. It might be preferable to |
| // perform this allocation only once, and re-use the `MPlaceTy`. |
| // See https://github.com/rust-lang/rust/pull/89920#discussion_r730012398 |
| ecx.allocate_str("<redacted>", MemoryKind::CallerLocation, Mutability::Not).unwrap() |
| }; |
| let line = if loc_details.line { Scalar::from_u32(line) } else { Scalar::from_u32(0) }; |
| let col = if loc_details.column { Scalar::from_u32(col) } else { Scalar::from_u32(0) }; |
| |
| // Allocate memory for `CallerLocation` struct. |
| let loc_ty = ecx |
| .tcx |
| .type_of(ecx.tcx.require_lang_item(LangItem::PanicLocation, None)) |
| .instantiate(*ecx.tcx, ecx.tcx.mk_args(&[ecx.tcx.lifetimes.re_erased.into()])); |
| let loc_layout = ecx.layout_of(loc_ty).unwrap(); |
| let location = ecx.allocate(loc_layout, MemoryKind::CallerLocation).unwrap(); |
| |
| // Initialize fields. |
| ecx.write_immediate(file.to_ref(ecx), &ecx.project_field(&location, 0).unwrap()) |
| .expect("writing to memory we just allocated cannot fail"); |
| ecx.write_scalar(line, &ecx.project_field(&location, 1).unwrap()) |
| .expect("writing to memory we just allocated cannot fail"); |
| ecx.write_scalar(col, &ecx.project_field(&location, 2).unwrap()) |
| .expect("writing to memory we just allocated cannot fail"); |
| |
| location |
| } |
| |
| pub(crate) fn const_caller_location_provider( |
| tcx: TyCtxtAt<'_>, |
| file: Symbol, |
| line: u32, |
| col: u32, |
| ) -> mir::ConstValue<'_> { |
| trace!("const_caller_location: {}:{}:{}", file, line, col); |
| let mut ecx = mk_eval_cx(tcx.tcx, tcx.span, ty::ParamEnv::reveal_all(), CanAccessStatics::No); |
| |
| let loc_place = alloc_caller_location(&mut ecx, file, line, col); |
| if intern_const_alloc_recursive(&mut ecx, InternKind::Constant, &loc_place).is_err() { |
| bug!("intern_const_alloc_recursive should not error in this case") |
| } |
| mir::ConstValue::Scalar(Scalar::from_maybe_pointer(loc_place.ptr(), &tcx)) |
| } |