diff options
| -rw-r--r-- | src/librustc_middle/ty/instance.rs | 46 | ||||
| -rw-r--r-- | src/test/codegen-units/polymorphization/pr-75255.rs | 37 |
2 files changed, 45 insertions, 38 deletions
diff --git a/src/librustc_middle/ty/instance.rs b/src/librustc_middle/ty/instance.rs index bdacc04c291..294bdd76d93 100644 --- a/src/librustc_middle/ty/instance.rs +++ b/src/librustc_middle/ty/instance.rs @@ -492,25 +492,6 @@ fn polymorphize<'tcx>( let unused = tcx.unused_generic_params(def_id); debug!("polymorphize: unused={:?}", unused); - if unused.is_empty() { - // Exit early if every parameter was used. - return substs; - } - - // If this is a closure or generator then we need to handle the case where another closure - // from the function is captured as an upvar and hasn't been polymorphized. In this case, - // the unpolymorphized upvar closure would result in a polymorphized closure producing - // multiple mono items (and eventually symbol clashes). - let upvars_ty = if tcx.is_closure(def_id) { - Some(substs.as_closure().tupled_upvars_ty()) - } else if tcx.type_of(def_id).is_generator() { - Some(substs.as_generator().tupled_upvars_ty()) - } else { - None - }; - let has_upvars = upvars_ty.map(|ty| ty.tuple_fields().count() > 0).unwrap_or(false); - debug!("polymorphize: upvars_ty={:?} has_upvars={:?}", upvars_ty, has_upvars); - struct PolymorphizationFolder<'tcx> { tcx: TyCtxt<'tcx>, }; @@ -540,31 +521,20 @@ fn polymorphize<'tcx>( let is_unused = unused.contains(param.index).unwrap_or(false); debug!("polymorphize: param={:?} is_unused={:?}", param, is_unused); match param.kind { - // Upvar case: If parameter is a type parameter.. - ty::GenericParamDefKind::Type { .. } if - // ..and has upvars.. - has_upvars && - // ..and this param has the same type as the tupled upvars.. - upvars_ty == Some(substs[param.index as usize].expect_ty()) => { - // ..then double-check that polymorphization marked it used.. - debug_assert!(!is_unused); - // ..and polymorphize any closures/generators captured as upvars. - let upvars_ty = upvars_ty.unwrap(); - let polymorphized_upvars_ty = upvars_ty.fold_with( - &mut PolymorphizationFolder { tcx }); - debug!("polymorphize: polymorphized_upvars_ty={:?}", polymorphized_upvars_ty); - ty::GenericArg::from(polymorphized_upvars_ty) - }, - - // Simple case: If parameter is a const or type parameter.. + // If parameter is a const or type parameter.. ty::GenericParamDefKind::Const | ty::GenericParamDefKind::Type { .. } if // ..and is within range and unused.. unused.contains(param.index).unwrap_or(false) => // ..then use the identity for this parameter. tcx.mk_param_from_def(param), - // Otherwise, use the parameter as before. - _ => substs[param.index as usize], + // Otherwise, use the parameter as before (polymorphizing any closures or generators). + _ => { + let arg = substs[param.index as usize]; + let polymorphized_arg = arg.fold_with(&mut PolymorphizationFolder { tcx }); + debug!("polymorphize: arg={:?} polymorphized_arg={:?}", arg, polymorphized_arg); + ty::GenericArg::from(polymorphized_arg) + } } }) } diff --git a/src/test/codegen-units/polymorphization/pr-75255.rs b/src/test/codegen-units/polymorphization/pr-75255.rs new file mode 100644 index 00000000000..ea9a6e8b181 --- /dev/null +++ b/src/test/codegen-units/polymorphization/pr-75255.rs @@ -0,0 +1,37 @@ +// compile-flags:-Zpolymorphize=on -Zprint-mono-items=lazy -Copt-level=1 +// ignore-tidy-linelength + +#![crate_type = "rlib"] + +// Test that only one copy of `Iter::map` is generated. + +fn foo<T>() { + let x = [1, 2, 3, std::mem::size_of::<T>()]; + x.iter().map(|_| ()); +} + +pub fn dispatch() { + foo::<String>(); + foo::<Vec<String>>(); +} + +//~ MONO_ITEM fn core::iter[0]::adapters[0]::{{impl}}[29]::new[0]<core::slice[0]::Iter[0]<usize>, pr_75255::foo[0]::{{closure}}[0]<T>> @@ pr_75255-cgu.0[External] +//~ MONO_ITEM fn core::iter[0]::traits[0]::iterator[0]::Iterator[0]::map[0]<core::slice[0]::Iter[0]<usize>, (), pr_75255::foo[0]::{{closure}}[0]<T>> @@ pr_75255-cgu.1[Internal] + +// These are all the items that aren't relevant to the test. +//~ MONO_ITEM fn core::mem[0]::size_of[0]<alloc::string[0]::String[0]> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::mem[0]::size_of[0]<alloc::vec[0]::Vec[0]<alloc::string[0]::String[0]>> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::mem[0]::size_of[0]<usize> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::ptr[0]::const_ptr[0]::{{impl}}[0]::add[0]<usize> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::ptr[0]::const_ptr[0]::{{impl}}[0]::is_null[0]<usize> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::ptr[0]::const_ptr[0]::{{impl}}[0]::offset[0]<usize> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::ptr[0]::const_ptr[0]::{{impl}}[0]::wrapping_add[0]<u8> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::ptr[0]::const_ptr[0]::{{impl}}[0]::wrapping_offset[0]<u8> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::ptr[0]::non_null[0]::{{impl}}[3]::new_unchecked[0]<usize> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::ptr[0]::null[0]<u8> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::slice[0]::{{impl}}[0]::as_ptr[0]<usize> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::slice[0]::{{impl}}[0]::iter[0]<usize> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn core::slice[0]::{{impl}}[0]::len[0]<usize> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn pr_75255::dispatch[0] @@ pr_75255-cgu.1[External] +//~ MONO_ITEM fn pr_75255::foo[0]<alloc::string[0]::String[0]> @@ pr_75255-cgu.1[Internal] +//~ MONO_ITEM fn pr_75255::foo[0]<alloc::vec[0]::Vec[0]<alloc::string[0]::String[0]>> @@ pr_75255-cgu.1[Internal] |