diff options
Diffstat (limited to 'src/librustc_codegen_llvm/mir/mod.rs')
| -rw-r--r-- | src/librustc_codegen_llvm/mir/mod.rs | 58 |
1 files changed, 46 insertions, 12 deletions
diff --git a/src/librustc_codegen_llvm/mir/mod.rs b/src/librustc_codegen_llvm/mir/mod.rs index 8bb049be305..d7bad05a66c 100644 --- a/src/librustc_codegen_llvm/mir/mod.rs +++ b/src/librustc_codegen_llvm/mir/mod.rs @@ -180,6 +180,11 @@ impl FunctionCx<'a, 'll, 'tcx> { enum LocalRef<'ll, 'tcx> { Place(PlaceRef<'ll, 'tcx>), + /// `UnsizedPlace(p)`: `p` itself is a thin pointer (indirect place). + /// `*p` is the fat pointer that references the actual unsized place. + /// Every time it is initialized, we have to reallocate the place + /// and update the fat pointer. That's the reason why it is indirect. + UnsizedPlace(PlaceRef<'ll, 'tcx>), Operand(Option<OperandRef<'ll, 'tcx>>), } @@ -275,17 +280,24 @@ pub fn codegen_mir( } debug!("alloc: {:?} ({}) -> place", local, name); - let place = PlaceRef::alloca(&bx, layout, &name.as_str()); - if dbg { - let (scope, span) = fx.debug_loc(mir::SourceInfo { - span: decl.source_info.span, - scope: decl.visibility_scope, - }); - declare_local(&bx, &fx.debug_context, name, layout.ty, scope.unwrap(), - VariableAccess::DirectVariable { alloca: place.llval }, - VariableKind::LocalVariable, span); + if layout.is_unsized() { + let indirect_place = + PlaceRef::alloca_unsized_indirect(&bx, layout, &name.as_str()); + // FIXME: add an appropriate debuginfo + LocalRef::UnsizedPlace(indirect_place) + } else { + let place = PlaceRef::alloca(&bx, layout, &name.as_str()); + if dbg { + let (scope, span) = fx.debug_loc(mir::SourceInfo { + span: decl.source_info.span, + scope: decl.visibility_scope, + }); + declare_local(&bx, &fx.debug_context, name, layout.ty, scope.unwrap(), + VariableAccess::DirectVariable { alloca: place.llval }, + VariableKind::LocalVariable, span); + } + LocalRef::Place(place) } - LocalRef::Place(place) } else { // Temporary or return place if local == mir::RETURN_PLACE && fx.fn_ty.ret.is_indirect() { @@ -294,7 +306,13 @@ pub fn codegen_mir( LocalRef::Place(PlaceRef::new_sized(llretptr, layout, layout.align)) } else if memory_locals.contains(local) { debug!("alloc: {:?} -> place", local); - LocalRef::Place(PlaceRef::alloca(&bx, layout, &format!("{:?}", local))) + if layout.is_unsized() { + let indirect_place = + PlaceRef::alloca_unsized_indirect(&bx, layout, &format!("{:?}", local)); + LocalRef::UnsizedPlace(indirect_place) + } else { + LocalRef::Place(PlaceRef::alloca(&bx, layout, &format!("{:?}", local))) + } } else { // If this is an immediate local, we do not create an // alloca in advance. Instead we wait until we see the @@ -531,6 +549,18 @@ fn arg_local_refs( bx.set_value_name(llarg, &name); llarg_idx += 1; PlaceRef::new_sized(llarg, arg.layout, arg.layout.align) + } else if arg.is_unsized_indirect() { + // As the storage for the indirect argument lives during + // the whole function call, we just copy the fat pointer. + let llarg = llvm::get_param(bx.llfn(), llarg_idx as c_uint); + llarg_idx += 1; + let llextra = llvm::get_param(bx.llfn(), llarg_idx as c_uint); + llarg_idx += 1; + let indirect_operand = OperandValue::Pair(llarg, llextra); + + let tmp = PlaceRef::alloca_unsized_indirect(bx, arg.layout, &name); + indirect_operand.store(&bx, tmp); + tmp } else { let tmp = PlaceRef::alloca(bx, arg.layout, &name); arg.store_fn_arg(bx, &mut llarg_idx, tmp); @@ -632,7 +662,11 @@ fn arg_local_refs( ); } }); - LocalRef::Place(place) + if arg.is_unsized_indirect() { + LocalRef::UnsizedPlace(place) + } else { + LocalRef::Place(place) + } }).collect() } |