diff options
| -rw-r--r-- | compiler/rustc_const_eval/src/interpret/util.rs | 3 | ||||
| -rw-r--r-- | compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs | 6 | ||||
| -rw-r--r-- | compiler/rustc_metadata/src/rmeta/encoder.rs | 4 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/mono.rs | 8 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/query/mod.rs | 6 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/ty/instance.rs | 45 | ||||
| -rw-r--r-- | compiler/rustc_monomorphize/src/collector.rs | 24 | ||||
| -rw-r--r-- | compiler/rustc_monomorphize/src/partitioning/default.rs | 25 | ||||
| -rw-r--r-- | compiler/rustc_monomorphize/src/polymorphize.rs | 125 | ||||
| -rw-r--r-- | src/test/ui/polymorphization/predicates.rs | 5 | ||||
| -rw-r--r-- | src/test/ui/polymorphization/predicates.stderr | 39 |
11 files changed, 182 insertions, 108 deletions
diff --git a/compiler/rustc_const_eval/src/interpret/util.rs b/compiler/rustc_const_eval/src/interpret/util.rs index eb0fdebb665..a16388d5de2 100644 --- a/compiler/rustc_const_eval/src/interpret/util.rs +++ b/compiler/rustc_const_eval/src/interpret/util.rs @@ -35,7 +35,8 @@ where ty::Closure(def_id, substs) | ty::Generator(def_id, substs, ..) | ty::FnDef(def_id, substs) => { - let unused_params = self.tcx.unused_generic_params(def_id); + let instance = ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)); + let unused_params = self.tcx.unused_generic_params(instance); for (index, subst) in substs.into_iter().enumerate() { let index = index .try_into() diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs index 4e7f85d2c37..e12f049a90b 100644 --- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs +++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs @@ -83,6 +83,12 @@ impl IntoArgs for (CrateNum, DefId) { } } +impl IntoArgs for ty::InstanceDef<'tcx> { + fn into_args(self) -> (DefId, DefId) { + (self.def_id(), self.def_id()) + } +} + provide! { <'tcx> tcx, def_id, other, cdata, type_of => { cdata.get_type(def_id.index, tcx) } generics_of => { cdata.get_generics(def_id.index, tcx.sess) } diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs index dacb1e4029c..20f7b059b56 100644 --- a/compiler/rustc_metadata/src/rmeta/encoder.rs +++ b/compiler/rustc_metadata/src/rmeta/encoder.rs @@ -1319,7 +1319,9 @@ impl EncodeContext<'a, 'tcx> { } record!(self.tables.promoted_mir[def_id.to_def_id()] <- self.tcx.promoted_mir(def_id)); - let unused = self.tcx.unused_generic_params(def_id); + let instance = + ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id.to_def_id())); + let unused = self.tcx.unused_generic_params(instance); if !unused.is_empty() { record!(self.tables.unused_generic_params[def_id.to_def_id()] <- unused); } diff --git a/compiler/rustc_middle/src/mir/mono.rs b/compiler/rustc_middle/src/mir/mono.rs index 67a20d72905..06b42320049 100644 --- a/compiler/rustc_middle/src/mir/mono.rs +++ b/compiler/rustc_middle/src/mir/mono.rs @@ -47,6 +47,14 @@ pub enum MonoItem<'tcx> { } impl<'tcx> MonoItem<'tcx> { + /// Returns `true` if the mono item is user-defined (i.e. not compiler-generated, like shims). + pub fn is_user_defined(&self) -> bool { + match *self { + MonoItem::Fn(instance) => matches!(instance.def, InstanceDef::Item(..)), + MonoItem::Static(..) | MonoItem::GlobalAsm(..) => true, + } + } + pub fn size_estimate(&self, tcx: TyCtxt<'tcx>) -> usize { match *self { MonoItem::Fn(instance) => { diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs index e3eda8483b6..4145cbd4249 100644 --- a/compiler/rustc_middle/src/query/mod.rs +++ b/compiler/rustc_middle/src/query/mod.rs @@ -1558,11 +1558,11 @@ rustc_queries! { query codegen_unit(_: Symbol) -> &'tcx CodegenUnit<'tcx> { desc { "codegen_unit" } } - query unused_generic_params(key: DefId) -> FiniteBitSet<u32> { - cache_on_disk_if { key.is_local() } + query unused_generic_params(key: ty::InstanceDef<'tcx>) -> FiniteBitSet<u32> { + cache_on_disk_if { key.def_id().is_local() } desc { |tcx| "determining which generic parameters are unused by `{}`", - tcx.def_path_str(key) + tcx.def_path_str(key.def_id()) } } query backend_optimization_level(_: ()) -> OptLevel { diff --git a/compiler/rustc_middle/src/ty/instance.rs b/compiler/rustc_middle/src/ty/instance.rs index 9b8247fd028..4b38105e447 100644 --- a/compiler/rustc_middle/src/ty/instance.rs +++ b/compiler/rustc_middle/src/ty/instance.rs @@ -152,6 +152,22 @@ impl<'tcx> InstanceDef<'tcx> { } } + /// Returns the `DefId` of instances which might not require codegen locally. + pub fn def_id_if_not_guaranteed_local_codegen(self) -> Option<DefId> { + match self { + ty::InstanceDef::Item(def) => Some(def.did), + ty::InstanceDef::DropGlue(def_id, Some(_)) => Some(def_id), + InstanceDef::VtableShim(..) + | InstanceDef::ReifyShim(..) + | InstanceDef::FnPtrShim(..) + | InstanceDef::Virtual(..) + | InstanceDef::Intrinsic(..) + | InstanceDef::ClosureOnceShim { .. } + | InstanceDef::DropGlue(..) + | InstanceDef::CloneShim(..) => None, + } + } + #[inline] pub fn with_opt_param(self) -> ty::WithOptConstParam<DefId> { match self { @@ -567,29 +583,26 @@ impl<'tcx> Instance<'tcx> { return self; } - if let InstanceDef::Item(def) = self.def { - let polymorphized_substs = polymorphize(tcx, def.did, self.substs); - debug!("polymorphize: self={:?} polymorphized_substs={:?}", self, polymorphized_substs); - Self { def: self.def, substs: polymorphized_substs } - } else { - self - } + let polymorphized_substs = polymorphize(tcx, self.def, self.substs); + debug!("polymorphize: self={:?} polymorphized_substs={:?}", self, polymorphized_substs); + Self { def: self.def, substs: polymorphized_substs } } } fn polymorphize<'tcx>( tcx: TyCtxt<'tcx>, - def_id: DefId, + instance: ty::InstanceDef<'tcx>, substs: SubstsRef<'tcx>, ) -> SubstsRef<'tcx> { - debug!("polymorphize({:?}, {:?})", def_id, substs); - let unused = tcx.unused_generic_params(def_id); + debug!("polymorphize({:?}, {:?})", instance, substs); + let unused = tcx.unused_generic_params(instance); debug!("polymorphize: unused={:?}", unused); // 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 def_id = instance.def_id(); 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() { @@ -613,7 +626,11 @@ fn polymorphize<'tcx>( debug!("fold_ty: ty={:?}", ty); match ty.kind { ty::Closure(def_id, substs) => { - let polymorphized_substs = polymorphize(self.tcx, def_id, substs); + let polymorphized_substs = polymorphize( + self.tcx, + ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)), + substs, + ); if substs == polymorphized_substs { ty } else { @@ -621,7 +638,11 @@ fn polymorphize<'tcx>( } } ty::Generator(def_id, substs, movability) => { - let polymorphized_substs = polymorphize(self.tcx, def_id, substs); + let polymorphized_substs = polymorphize( + self.tcx, + ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)), + substs, + ); if substs == polymorphized_substs { ty } else { diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs index f06426308a2..5147408210e 100644 --- a/compiler/rustc_monomorphize/src/collector.rs +++ b/compiler/rustc_monomorphize/src/collector.rs @@ -450,7 +450,9 @@ fn collect_items_rec<'tcx>( // involving a dependency, and the lack of context is confusing) in this MVP, we focus on // diagnostics on edges crossing a crate boundary: the collected mono items which are not // defined in the local crate. - if tcx.sess.diagnostic().err_count() > error_count && starting_point.node.krate() != LOCAL_CRATE + if tcx.sess.diagnostic().err_count() > error_count + && starting_point.node.krate() != LOCAL_CRATE + && starting_point.node.is_user_defined() { let formatted_item = with_no_trimmed_paths(|| starting_point.node.to_string()); tcx.sess.span_note_without_error( @@ -934,21 +936,13 @@ fn visit_instance_use<'tcx>( } } -// Returns `true` if we should codegen an instance in the local crate. -// Returns `false` if we can just link to the upstream crate and therefore don't -// need a mono item. +/// Returns `true` if we should codegen an instance in the local crate, or returns `false` if we +/// can just link to the upstream crate and therefore don't need a mono item. fn should_codegen_locally<'tcx>(tcx: TyCtxt<'tcx>, instance: &Instance<'tcx>) -> bool { - let def_id = match instance.def { - ty::InstanceDef::Item(def) => def.did, - ty::InstanceDef::DropGlue(def_id, Some(_)) => def_id, - ty::InstanceDef::VtableShim(..) - | ty::InstanceDef::ReifyShim(..) - | ty::InstanceDef::ClosureOnceShim { .. } - | ty::InstanceDef::Virtual(..) - | ty::InstanceDef::FnPtrShim(..) - | ty::InstanceDef::DropGlue(..) - | ty::InstanceDef::Intrinsic(_) - | ty::InstanceDef::CloneShim(..) => return true, + let def_id = if let Some(def_id) = instance.def.def_id_if_not_guaranteed_local_codegen() { + def_id + } else { + return true; }; if tcx.is_foreign_item(def_id) { diff --git a/compiler/rustc_monomorphize/src/partitioning/default.rs b/compiler/rustc_monomorphize/src/partitioning/default.rs index 429ed53d379..be682082258 100644 --- a/compiler/rustc_monomorphize/src/partitioning/default.rs +++ b/compiler/rustc_monomorphize/src/partitioning/default.rs @@ -9,7 +9,7 @@ use rustc_middle::middle::exported_symbols::SymbolExportLevel; use rustc_middle::mir::mono::{CodegenUnit, CodegenUnitNameBuilder, Linkage, Visibility}; use rustc_middle::mir::mono::{InstantiationMode, MonoItem}; use rustc_middle::ty::print::characteristic_def_id_of_type; -use rustc_middle::ty::{self, DefIdTree, InstanceDef, TyCtxt}; +use rustc_middle::ty::{self, fold::TypeFoldable, DefIdTree, InstanceDef, TyCtxt}; use rustc_span::symbol::Symbol; use super::PartitioningCx; @@ -300,14 +300,21 @@ fn characteristic_def_id_of_mono_item<'tcx>( // call it. return None; } - // This is a method within an impl, find out what the self-type is: - let impl_self_ty = tcx.subst_and_normalize_erasing_regions( - instance.substs, - ty::ParamEnv::reveal_all(), - tcx.type_of(impl_def_id), - ); - if let Some(def_id) = characteristic_def_id_of_type(impl_self_ty) { - return Some(def_id); + + // When polymorphization is enabled, methods which do not depend on their generic + // parameters, but the self-type of their impl block do will fail to normalize. + if !tcx.sess.opts.debugging_opts.polymorphize + || !instance.definitely_needs_subst(tcx) + { + // This is a method within an impl, find out what the self-type is: + let impl_self_ty = tcx.subst_and_normalize_erasing_regions( + instance.substs, + ty::ParamEnv::reveal_all(), + tcx.type_of(impl_def_id), + ); + if let Some(def_id) = characteristic_def_id_of_type(impl_self_ty) { + return Some(def_id); + } } } diff --git a/compiler/rustc_monomorphize/src/polymorphize.rs b/compiler/rustc_monomorphize/src/polymorphize.rs index 0f768b7819b..e6e4438b6d4 100644 --- a/compiler/rustc_monomorphize/src/polymorphize.rs +++ b/compiler/rustc_monomorphize/src/polymorphize.rs @@ -27,20 +27,23 @@ pub fn provide(providers: &mut Providers) { providers.unused_generic_params = unused_generic_params; } -/// Determine which generic parameters are used by the function/method/closure represented by -/// `def_id`. Returns a bitset where bits representing unused parameters are set (`is_empty` -/// indicates all parameters are used). +/// Determine which generic parameters are used by the instance. +/// +/// Returns a bitset where bits representing unused parameters are set (`is_empty` indicates all +/// parameters are used). #[instrument(level = "debug", skip(tcx))] -fn unused_generic_params(tcx: TyCtxt<'_>, def_id: DefId) -> FiniteBitSet<u32> { +fn unused_generic_params<'tcx>( + tcx: TyCtxt<'tcx>, + instance: ty::InstanceDef<'tcx>, +) -> FiniteBitSet<u32> { if !tcx.sess.opts.debugging_opts.polymorphize { // If polymorphization disabled, then all parameters are used. return FiniteBitSet::new_empty(); } - // Polymorphization results are stored in cross-crate metadata only when there are unused - // parameters, so assume that non-local items must have only used parameters (else this query - // would not be invoked, and the cross-crate metadata used instead). - if !def_id.is_local() { + let def_id = instance.def_id(); + // Exit early if this instance should not be polymorphized. + if !should_polymorphize(tcx, def_id, instance) { return FiniteBitSet::new_empty(); } @@ -52,41 +55,25 @@ fn unused_generic_params(tcx: TyCtxt<'_>, def_id: DefId) -> FiniteBitSet<u32> { return FiniteBitSet::new_empty(); } - // Exit early when there is no MIR available. - let context = tcx.hir().body_const_context(def_id.expect_local()); - match context { - Some(ConstContext::ConstFn) | None if !tcx.is_mir_available(def_id) => { - debug!("no mir available"); - return FiniteBitSet::new_empty(); - } - Some(_) if !tcx.is_ctfe_mir_available(def_id) => { - debug!("no ctfe mir available"); - return FiniteBitSet::new_empty(); - } - _ => {} - } - // Create a bitset with N rightmost ones for each parameter. let generics_count: u32 = generics.count().try_into().expect("more generic parameters than can fit into a `u32`"); let mut unused_parameters = FiniteBitSet::<u32>::new_empty(); unused_parameters.set_range(0..generics_count); debug!(?unused_parameters, "(start)"); + mark_used_by_default_parameters(tcx, def_id, generics, &mut unused_parameters); debug!(?unused_parameters, "(after default)"); // Visit MIR and accumululate used generic parameters. - let body = match context { + let body = match tcx.hir().body_const_context(def_id.expect_local()) { // Const functions are actually called and should thus be considered for polymorphization - // via their runtime MIR + // via their runtime MIR. Some(ConstContext::ConstFn) | None => tcx.optimized_mir(def_id), Some(_) => tcx.mir_for_ctfe(def_id), }; let mut vis = MarkUsedGenericParams { tcx, def_id, unused_parameters: &mut unused_parameters }; vis.visit_body(body); - debug!(?unused_parameters, "(after visitor)"); - - mark_used_by_predicates(tcx, def_id, &mut unused_parameters); debug!(?unused_parameters, "(end)"); // Emit errors for debugging and testing if enabled. @@ -97,6 +84,49 @@ fn unused_generic_params(tcx: TyCtxt<'_>, def_id: DefId) -> FiniteBitSet<u32> { unused_parameters } +/// Returns `true` if the instance should be polymorphized. +fn should_polymorphize<'tcx>( + tcx: TyCtxt<'tcx>, + def_id: DefId, + instance: ty::InstanceDef<'tcx>, +) -> bool { + // If an instance's MIR body is not polymorphic then the modified substitutions that are + // derived from polymorphization's result won't make any difference. + if !instance.has_polymorphic_mir_body() { + return false; + } + + // Don't polymorphize intrinsics or virtual calls - calling `instance_mir` will panic. + if matches!(instance, ty::InstanceDef::Intrinsic(..) | ty::InstanceDef::Virtual(..)) { + return false; + } + + // Polymorphization results are stored in cross-crate metadata only when there are unused + // parameters, so assume that non-local items must have only used parameters (else this query + // would not be invoked, and the cross-crate metadata used instead). + if !def_id.is_local() { + return false; + } + + // Foreign items have no bodies to analyze. + if tcx.is_foreign_item(def_id) { + return false; + } + + // Make sure there is MIR available. + match tcx.hir().body_const_context(def_id.expect_local()) { + Some(ConstContext::ConstFn) | None if !tcx.is_mir_available(def_id) => { + debug!("no mir available"); + return false; + } + Some(_) if !tcx.is_ctfe_mir_available(def_id) => { + debug!("no ctfe mir available"); + return false; + } + _ => true, + } +} + /// Some parameters are considered used-by-default, such as non-generic parameters and the dummy /// generic parameters from closures, this function marks them as used. `leaf_is_closure` should /// be `true` if the item that `unused_generic_params` was invoked on is a closure. @@ -156,44 +186,6 @@ fn mark_used_by_default_parameters<'tcx>( } } -/// Search the predicates on used generic parameters for any unused generic parameters, and mark -/// those as used. -#[instrument(level = "debug", skip(tcx, def_id))] -fn mark_used_by_predicates<'tcx>( - tcx: TyCtxt<'tcx>, - def_id: DefId, - unused_parameters: &mut FiniteBitSet<u32>, -) { - let def_id = tcx.closure_base_def_id(def_id); - let predicates = tcx.explicit_predicates_of(def_id); - - let mut current_unused_parameters = FiniteBitSet::new_empty(); - // Run to a fixed point to support `where T: Trait<U>, U: Trait<V>`, starting with an empty - // bit set so that this is skipped if all parameters are already used. - while current_unused_parameters != *unused_parameters { - debug!(?current_unused_parameters, ?unused_parameters); - current_unused_parameters = *unused_parameters; - - for (predicate, _) in predicates.predicates { - // Consider all generic params in a predicate as used if any other parameter in the - // predicate is used. - let any_param_used = { - let mut vis = HasUsedGenericParams { tcx, unused_parameters }; - predicate.visit_with(&mut vis).is_break() - }; - - if any_param_used { - let mut vis = MarkUsedGenericParams { tcx, def_id, unused_parameters }; - predicate.visit_with(&mut vis); - } - } - } - - if let Some(parent) = predicates.parent { - mark_used_by_predicates(tcx, parent, unused_parameters); - } -} - /// Emit errors for the function annotated by `#[rustc_polymorphize_error]`, labelling each generic /// parameter which was unused. #[instrument(level = "debug", skip(tcx, generics))] @@ -243,7 +235,8 @@ impl<'a, 'tcx> MarkUsedGenericParams<'a, 'tcx> { /// a closure, generator or constant). #[instrument(level = "debug", skip(self, def_id, substs))] fn visit_child_body(&mut self, def_id: DefId, substs: SubstsRef<'tcx>) { - let unused = self.tcx.unused_generic_params(def_id); + let instance = ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)); + let unused = self.tcx.unused_generic_params(instance); debug!(?self.unused_parameters, ?unused); for (i, arg) in substs.iter().enumerate() { let i = i.try_into().unwrap(); diff --git a/src/test/ui/polymorphization/predicates.rs b/src/test/ui/polymorphization/predicates.rs index 97f1ef2c90a..dea1e21e77f 100644 --- a/src/test/ui/polymorphization/predicates.rs +++ b/src/test/ui/polymorphization/predicates.rs @@ -12,6 +12,7 @@ fn bar<I>() { #[rustc_polymorphize_error] fn foo<I, T>(_: I) +//~^ ERROR item has unused generic parameters where I: Iterator<Item = T>, { @@ -20,6 +21,7 @@ where #[rustc_polymorphize_error] fn baz<I, T>(_: I) +//~^ ERROR item has unused generic parameters where std::iter::Repeat<I>: Iterator<Item = T>, { @@ -40,6 +42,7 @@ where #[rustc_polymorphize_error] fn next(&mut self) -> Option<Self::Item> { self.find(|_| true) + //~^ ERROR item has unused generic parameters } } @@ -53,6 +56,7 @@ impl Baz<u32> for u16 {} #[rustc_polymorphize_error] fn quux<A, B, C: Default>() -> usize +//~^ ERROR item has unused generic parameters where A: Baz<B>, B: Baz<C>, @@ -69,6 +73,7 @@ impl Foobar<u32, u32> for () {} #[rustc_polymorphize_error] fn foobar<F, G>() -> usize +//~^ ERROR item has unused generic parameters where (): Foobar<F, G>, { diff --git a/src/test/ui/polymorphization/predicates.stderr b/src/test/ui/polymorphization/predicates.stderr index c23730fc995..5fc51e58d72 100644 --- a/src/test/ui/polymorphization/predicates.stderr +++ b/src/test/ui/polymorphization/predicates.stderr @@ -1,8 +1,45 @@ error: item has unused generic parameters + --> $DIR/predicates.rs:14:4 + | +LL | fn foo<I, T>(_: I) + | ^^^ - generic parameter `T` is unused + +error: item has unused generic parameters + --> $DIR/predicates.rs:23:4 + | +LL | fn baz<I, T>(_: I) + | ^^^ - generic parameter `T` is unused + +error: item has unused generic parameters + --> $DIR/predicates.rs:44:19 + | +LL | impl<'a, I, T: 'a, E> Iterator for Foo<'a, I, E> + | - - generic parameter `E` is unused + | | + | generic parameter `I` is unused +... +LL | self.find(|_| true) + | ^^^^^^^^ + +error: item has unused generic parameters + --> $DIR/predicates.rs:58:4 + | +LL | fn quux<A, B, C: Default>() -> usize + | ^^^^ - - generic parameter `B` is unused + | | + | generic parameter `A` is unused + +error: item has unused generic parameters + --> $DIR/predicates.rs:75:4 + | +LL | fn foobar<F, G>() -> usize + | ^^^^^^ - generic parameter `F` is unused + +error: item has unused generic parameters --> $DIR/predicates.rs:9:4 | LL | fn bar<I>() { | ^^^ - generic parameter `I` is unused -error: aborting due to previous error +error: aborting due to 6 previous errors |