| use crate::monomorphize::Instance; |
| use rustc::hir; |
| use rustc::hir::def_id::{DefId, LOCAL_CRATE}; |
| use rustc::mir::interpret::ConstValue; |
| use rustc::session::config::OptLevel; |
| use rustc::ty::{self, Ty, TyCtxt, Const, ClosureSubsts, GeneratorSubsts, ParamConst}; |
| use rustc::ty::subst::{SubstsRef, InternalSubsts}; |
| use syntax::ast; |
| use syntax::attr::InlineAttr; |
| use std::fmt::{self, Write}; |
| use std::iter; |
| use rustc::mir::mono::Linkage; |
| use syntax_pos::symbol::Symbol; |
| use syntax::source_map::Span; |
| pub use rustc::mir::mono::MonoItem; |
| |
| /// Describes how a monomorphization will be instantiated in object files. |
| #[derive(PartialEq, Eq, Clone, Copy, Debug, Hash)] |
| pub enum InstantiationMode { |
| /// There will be exactly one instance of the given MonoItem. It will have |
| /// external linkage so that it can be linked to from other codegen units. |
| GloballyShared { |
| /// In some compilation scenarios we may decide to take functions that |
| /// are typically `LocalCopy` and instead move them to `GloballyShared` |
| /// to avoid codegenning them a bunch of times. In this situation, |
| /// however, our local copy may conflict with other crates also |
| /// inlining the same function. |
| /// |
| /// This flag indicates that this situation is occurring, and informs |
| /// symbol name calculation that some extra mangling is needed to |
| /// avoid conflicts. Note that this may eventually go away entirely if |
| /// ThinLTO enables us to *always* have a globally shared instance of a |
| /// function within one crate's compilation. |
| may_conflict: bool, |
| }, |
| |
| /// Each codegen unit containing a reference to the given MonoItem will |
| /// have its own private copy of the function (with internal linkage). |
| LocalCopy, |
| } |
| |
| pub trait MonoItemExt<'a, 'tcx>: fmt::Debug { |
| fn as_mono_item(&self) -> &MonoItem<'tcx>; |
| |
| fn is_generic_fn(&self) -> bool { |
| match *self.as_mono_item() { |
| MonoItem::Fn(ref instance) => { |
| instance.substs.non_erasable_generics().next().is_some() |
| } |
| MonoItem::Static(..) | |
| MonoItem::GlobalAsm(..) => false, |
| } |
| } |
| |
| fn symbol_name(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> ty::SymbolName { |
| match *self.as_mono_item() { |
| MonoItem::Fn(instance) => tcx.symbol_name(instance), |
| MonoItem::Static(def_id) => { |
| tcx.symbol_name(Instance::mono(tcx, def_id)) |
| } |
| MonoItem::GlobalAsm(hir_id) => { |
| let def_id = tcx.hir().local_def_id_from_hir_id(hir_id); |
| ty::SymbolName { |
| name: Symbol::intern(&format!("global_asm_{:?}", def_id)).as_interned_str() |
| } |
| } |
| } |
| } |
| fn instantiation_mode(&self, |
| tcx: TyCtxt<'a, 'tcx, 'tcx>) |
| -> InstantiationMode { |
| let inline_in_all_cgus = |
| tcx.sess.opts.debugging_opts.inline_in_all_cgus.unwrap_or_else(|| { |
| tcx.sess.opts.optimize != OptLevel::No |
| }) && !tcx.sess.opts.cg.link_dead_code; |
| |
| match *self.as_mono_item() { |
| MonoItem::Fn(ref instance) => { |
| let entry_def_id = tcx.entry_fn(LOCAL_CRATE).map(|(id, _)| id); |
| // If this function isn't inlined or otherwise has explicit |
| // linkage, then we'll be creating a globally shared version. |
| if self.explicit_linkage(tcx).is_some() || |
| !instance.def.requires_local(tcx) || |
| Some(instance.def_id()) == entry_def_id |
| { |
| return InstantiationMode::GloballyShared { may_conflict: false } |
| } |
| |
| // At this point we don't have explicit linkage and we're an |
| // inlined function. If we're inlining into all CGUs then we'll |
| // be creating a local copy per CGU |
| if inline_in_all_cgus { |
| return InstantiationMode::LocalCopy |
| } |
| |
| // Finally, if this is `#[inline(always)]` we're sure to respect |
| // that with an inline copy per CGU, but otherwise we'll be |
| // creating one copy of this `#[inline]` function which may |
| // conflict with upstream crates as it could be an exported |
| // symbol. |
| match tcx.codegen_fn_attrs(instance.def_id()).inline { |
| InlineAttr::Always => InstantiationMode::LocalCopy, |
| _ => { |
| InstantiationMode::GloballyShared { may_conflict: true } |
| } |
| } |
| } |
| MonoItem::Static(..) | |
| MonoItem::GlobalAsm(..) => { |
| InstantiationMode::GloballyShared { may_conflict: false } |
| } |
| } |
| } |
| |
| fn explicit_linkage(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Option<Linkage> { |
| let def_id = match *self.as_mono_item() { |
| MonoItem::Fn(ref instance) => instance.def_id(), |
| MonoItem::Static(def_id) => def_id, |
| MonoItem::GlobalAsm(..) => return None, |
| }; |
| |
| let codegen_fn_attrs = tcx.codegen_fn_attrs(def_id); |
| codegen_fn_attrs.linkage |
| } |
| |
| /// Returns `true` if this instance is instantiable - whether it has no unsatisfied |
| /// predicates. |
| /// |
| /// In order to codegen an item, all of its predicates must hold, because |
| /// otherwise the item does not make sense. Type-checking ensures that |
| /// the predicates of every item that is *used by* a valid item *do* |
| /// hold, so we can rely on that. |
| /// |
| /// However, we codegen collector roots (reachable items) and functions |
| /// in vtables when they are seen, even if they are not used, and so they |
| /// might not be instantiable. For example, a programmer can define this |
| /// public function: |
| /// |
| /// pub fn foo<'a>(s: &'a mut ()) where &'a mut (): Clone { |
| /// <&mut () as Clone>::clone(&s); |
| /// } |
| /// |
| /// That function can't be codegened, because the method `<&mut () as Clone>::clone` |
| /// does not exist. Luckily for us, that function can't ever be used, |
| /// because that would require for `&'a mut (): Clone` to hold, so we |
| /// can just not emit any code, or even a linker reference for it. |
| /// |
| /// Similarly, if a vtable method has such a signature, and therefore can't |
| /// be used, we can just not emit it and have a placeholder (a null pointer, |
| /// which will never be accessed) in its place. |
| fn is_instantiable(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> bool { |
| debug!("is_instantiable({:?})", self); |
| let (def_id, substs) = match *self.as_mono_item() { |
| MonoItem::Fn(ref instance) => (instance.def_id(), instance.substs), |
| MonoItem::Static(def_id) => (def_id, InternalSubsts::empty()), |
| // global asm never has predicates |
| MonoItem::GlobalAsm(..) => return true |
| }; |
| |
| tcx.substitute_normalize_and_test_predicates((def_id, &substs)) |
| } |
| |
| fn to_string(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, debug: bool) -> String { |
| return match *self.as_mono_item() { |
| MonoItem::Fn(instance) => { |
| to_string_internal(tcx, "fn ", instance, debug) |
| }, |
| MonoItem::Static(def_id) => { |
| let instance = Instance::new(def_id, tcx.intern_substs(&[])); |
| to_string_internal(tcx, "static ", instance, debug) |
| }, |
| MonoItem::GlobalAsm(..) => { |
| "global_asm".to_string() |
| } |
| }; |
| |
| fn to_string_internal<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| prefix: &str, |
| instance: Instance<'tcx>, |
| debug: bool) |
| -> String { |
| let mut result = String::with_capacity(32); |
| result.push_str(prefix); |
| let printer = DefPathBasedNames::new(tcx, false, false); |
| printer.push_instance_as_string(instance, &mut result, debug); |
| result |
| } |
| } |
| |
| fn local_span(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Option<Span> { |
| match *self.as_mono_item() { |
| MonoItem::Fn(Instance { def, .. }) => { |
| tcx.hir().as_local_hir_id(def.def_id()) |
| } |
| MonoItem::Static(def_id) => { |
| tcx.hir().as_local_hir_id(def_id) |
| } |
| MonoItem::GlobalAsm(hir_id) => { |
| Some(hir_id) |
| } |
| }.map(|hir_id| tcx.hir().span_by_hir_id(hir_id)) |
| } |
| } |
| |
| impl<'a, 'tcx> MonoItemExt<'a, 'tcx> for MonoItem<'tcx> { |
| fn as_mono_item(&self) -> &MonoItem<'tcx> { |
| self |
| } |
| } |
| |
| //=----------------------------------------------------------------------------- |
| // MonoItem String Keys |
| //=----------------------------------------------------------------------------- |
| |
| // The code below allows for producing a unique string key for a mono item. |
| // These keys are used by the handwritten auto-tests, so they need to be |
| // predictable and human-readable. |
| // |
| // Note: A lot of this could looks very similar to what's already in `ty::print`. |
| // FIXME(eddyb) implement a custom `PrettyPrinter` for this. |
| |
| /// Same as `unique_type_name()` but with the result pushed onto the given |
| /// `output` parameter. |
| pub struct DefPathBasedNames<'a, 'tcx: 'a> { |
| tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| omit_disambiguators: bool, |
| omit_local_crate_name: bool, |
| } |
| |
| impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> { |
| pub fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| omit_disambiguators: bool, |
| omit_local_crate_name: bool) |
| -> Self { |
| DefPathBasedNames { |
| tcx, |
| omit_disambiguators, |
| omit_local_crate_name, |
| } |
| } |
| |
| // Pushes the type name of the specified type to the provided string. |
| // If 'debug' is true, printing normally unprintable types is allowed |
| // (e.g. ty::GeneratorWitness). This parameter should only be set when |
| // this method is being used for logging purposes (e.g. with debug! or info!) |
| // When being used for codegen purposes, 'debug' should be set to 'false' |
| // in order to catch unexpected types that should never end up in a type name |
| pub fn push_type_name(&self, t: Ty<'tcx>, output: &mut String, debug: bool) { |
| match t.sty { |
| ty::Bool => output.push_str("bool"), |
| ty::Char => output.push_str("char"), |
| ty::Str => output.push_str("str"), |
| ty::Never => output.push_str("!"), |
| ty::Int(ast::IntTy::Isize) => output.push_str("isize"), |
| ty::Int(ast::IntTy::I8) => output.push_str("i8"), |
| ty::Int(ast::IntTy::I16) => output.push_str("i16"), |
| ty::Int(ast::IntTy::I32) => output.push_str("i32"), |
| ty::Int(ast::IntTy::I64) => output.push_str("i64"), |
| ty::Int(ast::IntTy::I128) => output.push_str("i128"), |
| ty::Uint(ast::UintTy::Usize) => output.push_str("usize"), |
| ty::Uint(ast::UintTy::U8) => output.push_str("u8"), |
| ty::Uint(ast::UintTy::U16) => output.push_str("u16"), |
| ty::Uint(ast::UintTy::U32) => output.push_str("u32"), |
| ty::Uint(ast::UintTy::U64) => output.push_str("u64"), |
| ty::Uint(ast::UintTy::U128) => output.push_str("u128"), |
| ty::Float(ast::FloatTy::F32) => output.push_str("f32"), |
| ty::Float(ast::FloatTy::F64) => output.push_str("f64"), |
| ty::Adt(adt_def, substs) => { |
| self.push_def_path(adt_def.did, output); |
| self.push_generic_params(substs, iter::empty(), output, debug); |
| }, |
| ty::Tuple(component_types) => { |
| output.push('('); |
| for &component_type in component_types { |
| self.push_type_name(component_type, output, debug); |
| output.push_str(", "); |
| } |
| if !component_types.is_empty() { |
| output.pop(); |
| output.pop(); |
| } |
| output.push(')'); |
| }, |
| ty::RawPtr(ty::TypeAndMut { ty: inner_type, mutbl } ) => { |
| output.push('*'); |
| match mutbl { |
| hir::MutImmutable => output.push_str("const "), |
| hir::MutMutable => output.push_str("mut "), |
| } |
| |
| self.push_type_name(inner_type, output, debug); |
| }, |
| ty::Ref(_, inner_type, mutbl) => { |
| output.push('&'); |
| if mutbl == hir::MutMutable { |
| output.push_str("mut "); |
| } |
| |
| self.push_type_name(inner_type, output, debug); |
| }, |
| ty::Array(inner_type, len) => { |
| output.push('['); |
| self.push_type_name(inner_type, output, debug); |
| write!(output, "; {}", len.unwrap_usize(self.tcx)).unwrap(); |
| output.push(']'); |
| }, |
| ty::Slice(inner_type) => { |
| output.push('['); |
| self.push_type_name(inner_type, output, debug); |
| output.push(']'); |
| }, |
| ty::Dynamic(ref trait_data, ..) => { |
| if let Some(principal) = trait_data.principal() { |
| self.push_def_path(principal.def_id(), output); |
| self.push_generic_params( |
| principal.skip_binder().substs, |
| trait_data.projection_bounds(), |
| output, |
| debug |
| ); |
| } else { |
| output.push_str("dyn '_"); |
| } |
| }, |
| ty::Foreign(did) => self.push_def_path(did, output), |
| ty::FnDef(..) | |
| ty::FnPtr(_) => { |
| let sig = t.fn_sig(self.tcx); |
| if sig.unsafety() == hir::Unsafety::Unsafe { |
| output.push_str("unsafe "); |
| } |
| |
| let abi = sig.abi(); |
| if abi != ::rustc_target::spec::abi::Abi::Rust { |
| output.push_str("extern \""); |
| output.push_str(abi.name()); |
| output.push_str("\" "); |
| } |
| |
| output.push_str("fn("); |
| |
| let sig = self.tcx.normalize_erasing_late_bound_regions( |
| ty::ParamEnv::reveal_all(), |
| &sig, |
| ); |
| |
| if !sig.inputs().is_empty() { |
| for ¶meter_type in sig.inputs() { |
| self.push_type_name(parameter_type, output, debug); |
| output.push_str(", "); |
| } |
| output.pop(); |
| output.pop(); |
| } |
| |
| if sig.c_variadic { |
| if !sig.inputs().is_empty() { |
| output.push_str(", ..."); |
| } else { |
| output.push_str("..."); |
| } |
| } |
| |
| output.push(')'); |
| |
| if !sig.output().is_unit() { |
| output.push_str(" -> "); |
| self.push_type_name(sig.output(), output, debug); |
| } |
| }, |
| ty::Generator(def_id, GeneratorSubsts { ref substs }, _) | |
| ty::Closure(def_id, ClosureSubsts { ref substs }) => { |
| self.push_def_path(def_id, output); |
| let generics = self.tcx.generics_of(self.tcx.closure_base_def_id(def_id)); |
| let substs = substs.truncate_to(self.tcx, generics); |
| self.push_generic_params(substs, iter::empty(), output, debug); |
| } |
| ty::Error | |
| ty::Bound(..) | |
| ty::Infer(_) | |
| ty::Placeholder(..) | |
| ty::UnnormalizedProjection(..) | |
| ty::Projection(..) | |
| ty::Param(_) | |
| ty::GeneratorWitness(_) | |
| ty::Opaque(..) => { |
| if debug { |
| output.push_str(&format!("`{:?}`", t)); |
| } else { |
| bug!("DefPathBasedNames: Trying to create type name for \ |
| unexpected type: {:?}", t); |
| } |
| } |
| } |
| } |
| |
| // FIXME(const_generics): handle debug printing. |
| pub fn push_const_name(&self, c: &Const<'tcx>, output: &mut String, debug: bool) { |
| match c.val { |
| ConstValue::Infer(..) => output.push_str("_"), |
| ConstValue::Param(ParamConst { name, .. }) => { |
| write!(output, "{}", name).unwrap(); |
| } |
| ConstValue::Unevaluated(..) => output.push_str("_: _"), |
| _ => write!(output, "{:?}", c).unwrap(), |
| } |
| output.push_str(": "); |
| self.push_type_name(c.ty, output, debug); |
| } |
| |
| pub fn push_def_path(&self, |
| def_id: DefId, |
| output: &mut String) { |
| let def_path = self.tcx.def_path(def_id); |
| |
| // some_crate:: |
| if !(self.omit_local_crate_name && def_id.is_local()) { |
| output.push_str(&self.tcx.crate_name(def_path.krate).as_str()); |
| output.push_str("::"); |
| } |
| |
| // foo::bar::ItemName:: |
| for part in self.tcx.def_path(def_id).data { |
| if self.omit_disambiguators { |
| write!(output, "{}::", part.data.as_interned_str()).unwrap(); |
| } else { |
| write!(output, "{}[{}]::", |
| part.data.as_interned_str(), |
| part.disambiguator).unwrap(); |
| } |
| } |
| |
| // remove final "::" |
| output.pop(); |
| output.pop(); |
| } |
| |
| fn push_generic_params<I>( |
| &self, |
| substs: SubstsRef<'tcx>, |
| projections: I, |
| output: &mut String, |
| debug: bool, |
| ) where I: Iterator<Item=ty::PolyExistentialProjection<'tcx>> { |
| let mut projections = projections.peekable(); |
| if substs.non_erasable_generics().next().is_none() && projections.peek().is_none() { |
| return; |
| } |
| |
| output.push('<'); |
| |
| for type_parameter in substs.types() { |
| self.push_type_name(type_parameter, output, debug); |
| output.push_str(", "); |
| } |
| |
| for projection in projections { |
| let projection = projection.skip_binder(); |
| let name = &self.tcx.associated_item(projection.item_def_id).ident.as_str(); |
| output.push_str(name); |
| output.push_str("="); |
| self.push_type_name(projection.ty, output, debug); |
| output.push_str(", "); |
| } |
| |
| for const_parameter in substs.consts() { |
| self.push_const_name(const_parameter, output, debug); |
| output.push_str(", "); |
| } |
| |
| output.pop(); |
| output.pop(); |
| |
| output.push('>'); |
| } |
| |
| pub fn push_instance_as_string(&self, |
| instance: Instance<'tcx>, |
| output: &mut String, |
| debug: bool) { |
| self.push_def_path(instance.def_id(), output); |
| self.push_generic_params(instance.substs, iter::empty(), output, debug); |
| } |
| } |
