1262 lines
52 KiB
Rust
1262 lines
52 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! Translation Item Collection
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//! ===========================
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//!
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//! This module is responsible for discovering all items that will contribute to
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//! to code generation of the crate. The important part here is that it not only
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//! needs to find syntax-level items (functions, structs, etc) but also all
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//! their monomorphized instantiations. Every non-generic, non-const function
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//! maps to one LLVM artifact. Every generic function can produce
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//! from zero to N artifacts, depending on the sets of type arguments it
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//! is instantiated with.
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//! This also applies to generic items from other crates: A generic definition
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//! in crate X might produce monomorphizations that are compiled into crate Y.
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//! We also have to collect these here.
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//!
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//! The following kinds of "translation items" are handled here:
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//!
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//! - Functions
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//! - Methods
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//! - Closures
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//! - Statics
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//! - Drop glue
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//!
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//! The following things also result in LLVM artifacts, but are not collected
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//! here, since we instantiate them locally on demand when needed in a given
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//! codegen unit:
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//!
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//! - Constants
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//! - Vtables
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//! - Object Shims
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//!
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//!
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//! General Algorithm
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//! -----------------
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//! Let's define some terms first:
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//!
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//! - A "translation item" is something that results in a function or global in
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//! the LLVM IR of a codegen unit. Translation items do not stand on their
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//! own, they can reference other translation items. For example, if function
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//! `foo()` calls function `bar()` then the translation item for `foo()`
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//! references the translation item for function `bar()`. In general, the
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//! definition for translation item A referencing a translation item B is that
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//! the LLVM artifact produced for A references the LLVM artifact produced
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//! for B.
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//!
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//! - Translation items and the references between them for a directed graph,
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//! where the translation items are the nodes and references form the edges.
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//! Let's call this graph the "translation item graph".
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//!
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//! - The translation item graph for a program contains all translation items
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//! that are needed in order to produce the complete LLVM IR of the program.
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//!
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//! The purpose of the algorithm implemented in this module is to build the
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//! translation item graph for the current crate. It runs in two phases:
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//!
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//! 1. Discover the roots of the graph by traversing the HIR of the crate.
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//! 2. Starting from the roots, find neighboring nodes by inspecting the MIR
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//! representation of the item corresponding to a given node, until no more
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//! new nodes are found.
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//!
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//! ### Discovering roots
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//!
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//! The roots of the translation item graph correspond to the non-generic
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//! syntactic items in the source code. We find them by walking the HIR of the
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//! crate, and whenever we hit upon a function, method, or static item, we
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//! create a translation item consisting of the items DefId and, since we only
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//! consider non-generic items, an empty type-substitution set.
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//!
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//! ### Finding neighbor nodes
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//! Given a translation item node, we can discover neighbors by inspecting its
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//! MIR. We walk the MIR and any time we hit upon something that signifies a
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//! reference to another translation item, we have found a neighbor. Since the
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//! translation item we are currently at is always monomorphic, we also know the
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//! concrete type arguments of its neighbors, and so all neighbors again will be
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//! monomorphic. The specific forms a reference to a neighboring node can take
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//! in MIR are quite diverse. Here is an overview:
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//!
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//! #### Calling Functions/Methods
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//! The most obvious form of one translation item referencing another is a
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//! function or method call (represented by a CALL terminator in MIR). But
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//! calls are not the only thing that might introduce a reference between two
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//! function translation items, and as we will see below, they are just a
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//! specialized of the form described next, and consequently will don't get any
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//! special treatment in the algorithm.
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//!
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//! #### Taking a reference to a function or method
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//! A function does not need to actually be called in order to be a neighbor of
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//! another function. It suffices to just take a reference in order to introduce
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//! an edge. Consider the following example:
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//!
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//! ```rust
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//! fn print_val<T: Display>(x: T) {
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//! println!("{}", x);
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//! }
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//!
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//! fn call_fn(f: &Fn(i32), x: i32) {
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//! f(x);
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//! }
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//!
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//! fn main() {
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//! let print_i32 = print_val::<i32>;
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//! call_fn(&print_i32, 0);
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//! }
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//! ```
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//! The MIR of none of these functions will contain an explicit call to
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//! `print_val::<i32>`. Nonetheless, in order to translate this program, we need
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//! an instance of this function. Thus, whenever we encounter a function or
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//! method in operand position, we treat it as a neighbor of the current
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//! translation item. Calls are just a special case of that.
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//!
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//! #### Closures
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//! In a way, closures are a simple case. Since every closure object needs to be
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//! constructed somewhere, we can reliably discover them by observing
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//! `RValue::Aggregate` expressions with `AggregateKind::Closure`. This is also
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//! true for closures inlined from other crates.
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//!
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//! #### Drop glue
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//! Drop glue translation items are introduced by MIR drop-statements. The
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//! generated translation item will again have drop-glue item neighbors if the
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//! type to be dropped contains nested values that also need to be dropped. It
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//! might also have a function item neighbor for the explicit `Drop::drop`
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//! implementation of its type.
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//!
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//! #### Unsizing Casts
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//! A subtle way of introducing neighbor edges is by casting to a trait object.
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//! Since the resulting fat-pointer contains a reference to a vtable, we need to
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//! instantiate all object-save methods of the trait, as we need to store
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//! pointers to these functions even if they never get called anywhere. This can
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//! be seen as a special case of taking a function reference.
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//!
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//! #### Boxes
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//! Since `Box` expression have special compiler support, no explicit calls to
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//! `exchange_malloc()` and `exchange_free()` may show up in MIR, even if the
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//! compiler will generate them. We have to observe `Rvalue::Box` expressions
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//! and Box-typed drop-statements for that purpose.
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//!
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//!
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//! Interaction with Cross-Crate Inlining
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//! -------------------------------------
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//! The binary of a crate will not only contain machine code for the items
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//! defined in the source code of that crate. It will also contain monomorphic
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//! instantiations of any extern generic functions and of functions marked with
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//! #[inline].
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//! The collection algorithm handles this more or less transparently. If it is
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//! about to create a translation item for something with an external `DefId`,
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//! it will take a look if the MIR for that item is available, and if so just
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//! proceed normally. If the MIR is not available, it assumes that the item is
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//! just linked to and no node is created; which is exactly what we want, since
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//! no machine code should be generated in the current crate for such an item.
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//!
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//! Eager and Lazy Collection Mode
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//! ------------------------------
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//! Translation item collection can be performed in one of two modes:
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//!
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//! - Lazy mode means that items will only be instantiated when actually
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//! referenced. The goal is to produce the least amount of machine code
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//! possible.
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//!
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//! - Eager mode is meant to be used in conjunction with incremental compilation
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//! where a stable set of translation items is more important than a minimal
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//! one. Thus, eager mode will instantiate drop-glue for every drop-able type
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//! in the crate, even of no drop call for that type exists (yet). It will
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//! also instantiate default implementations of trait methods, something that
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//! otherwise is only done on demand.
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//!
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//!
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//! Open Issues
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//! -----------
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//! Some things are not yet fully implemented in the current version of this
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//! module.
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//!
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//! ### Initializers of Constants and Statics
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//! Since no MIR is constructed yet for initializer expressions of constants and
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//! statics we cannot inspect these properly.
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//!
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//! ### Const Fns
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//! Ideally, no translation item should be generated for const fns unless there
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//! is a call to them that cannot be evaluated at compile time. At the moment
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//! this is not implemented however: a translation item will be produced
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//! regardless of whether it is actually needed or not.
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use rustc::hir;
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use rustc::hir::intravisit as hir_visit;
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use rustc::hir::map as hir_map;
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use rustc::hir::def_id::DefId;
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use rustc::middle::lang_items::{ExchangeFreeFnLangItem, ExchangeMallocFnLangItem};
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use rustc::traits;
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use rustc::ty::subst::{Substs, Subst};
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use rustc::ty::{self, TypeFoldable, TyCtxt};
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use rustc::ty::adjustment::CustomCoerceUnsized;
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use rustc::mir::{self, Location};
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use rustc::mir::visit as mir_visit;
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use rustc::mir::visit::Visitor as MirVisitor;
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use rustc_const_eval as const_eval;
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use syntax::abi::Abi;
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use syntax_pos::DUMMY_SP;
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use base::custom_coerce_unsize_info;
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use context::SharedCrateContext;
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use common::{fulfill_obligation, type_is_sized};
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use glue::{self, DropGlueKind};
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use monomorphize::{self, Instance};
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use util::nodemap::{FnvHashSet, FnvHashMap, DefIdMap};
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use trans_item::{TransItem, type_to_string, def_id_to_string};
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#[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)]
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pub enum TransItemCollectionMode {
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Eager,
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Lazy
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}
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/// Maps every translation item to all translation items it references in its
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/// body.
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pub struct InliningMap<'tcx> {
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// Maps a source translation item to a range of target translation items
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// that are potentially inlined by LLVM into the source.
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// The two numbers in the tuple are the start (inclusive) and
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// end index (exclusive) within the `targets` vecs.
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index: FnvHashMap<TransItem<'tcx>, (usize, usize)>,
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targets: Vec<TransItem<'tcx>>,
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}
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impl<'tcx> InliningMap<'tcx> {
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fn new() -> InliningMap<'tcx> {
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InliningMap {
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index: FnvHashMap(),
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targets: Vec::new(),
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}
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}
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fn record_inlining_canditates<I>(&mut self,
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source: TransItem<'tcx>,
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targets: I)
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where I: Iterator<Item=TransItem<'tcx>>
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{
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assert!(!self.index.contains_key(&source));
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let start_index = self.targets.len();
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self.targets.extend(targets);
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let end_index = self.targets.len();
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self.index.insert(source, (start_index, end_index));
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}
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// Internally iterate over all items referenced by `source` which will be
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// made available for inlining.
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pub fn with_inlining_candidates<F>(&self, source: TransItem<'tcx>, mut f: F)
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where F: FnMut(TransItem<'tcx>) {
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if let Some(&(start_index, end_index)) = self.index.get(&source)
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{
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for candidate in &self.targets[start_index .. end_index] {
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f(*candidate)
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}
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}
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}
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}
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pub fn collect_crate_translation_items<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
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mode: TransItemCollectionMode)
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-> (FnvHashSet<TransItem<'tcx>>,
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InliningMap<'tcx>) {
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// We are not tracking dependencies of this pass as it has to be re-executed
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// every time no matter what.
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scx.tcx().dep_graph.with_ignore(|| {
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let roots = collect_roots(scx, mode);
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debug!("Building translation item graph, beginning at roots");
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let mut visited = FnvHashSet();
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let mut recursion_depths = DefIdMap();
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let mut inlining_map = InliningMap::new();
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for root in roots {
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collect_items_rec(scx,
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root,
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&mut visited,
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&mut recursion_depths,
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&mut inlining_map);
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}
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(visited, inlining_map)
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})
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}
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// Find all non-generic items by walking the HIR. These items serve as roots to
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// start monomorphizing from.
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fn collect_roots<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
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mode: TransItemCollectionMode)
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-> Vec<TransItem<'tcx>> {
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debug!("Collecting roots");
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let mut roots = Vec::new();
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{
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let mut visitor = RootCollector {
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scx: scx,
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mode: mode,
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output: &mut roots,
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enclosing_item: None,
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};
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scx.tcx().map.krate().visit_all_items(&mut visitor);
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}
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roots
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}
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// Collect all monomorphized translation items reachable from `starting_point`
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fn collect_items_rec<'a, 'tcx: 'a>(scx: &SharedCrateContext<'a, 'tcx>,
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starting_point: TransItem<'tcx>,
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visited: &mut FnvHashSet<TransItem<'tcx>>,
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recursion_depths: &mut DefIdMap<usize>,
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inlining_map: &mut InliningMap<'tcx>) {
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if !visited.insert(starting_point.clone()) {
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// We've been here already, no need to search again.
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return;
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}
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debug!("BEGIN collect_items_rec({})", starting_point.to_string(scx.tcx()));
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let mut neighbors = Vec::new();
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let recursion_depth_reset;
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match starting_point {
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TransItem::DropGlue(t) => {
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find_drop_glue_neighbors(scx, t, &mut neighbors);
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recursion_depth_reset = None;
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}
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TransItem::Static(node_id) => {
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let def_id = scx.tcx().map.local_def_id(node_id);
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let ty = scx.tcx().lookup_item_type(def_id).ty;
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let ty = glue::get_drop_glue_type(scx.tcx(), ty);
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neighbors.push(TransItem::DropGlue(DropGlueKind::Ty(ty)));
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recursion_depth_reset = None;
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// Scan the MIR in order to find function calls, closures, and
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// drop-glue
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let mir = scx.tcx().item_mir(def_id);
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let empty_substs = scx.empty_substs_for_def_id(def_id);
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let visitor = MirNeighborCollector {
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scx: scx,
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mir: &mir,
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output: &mut neighbors,
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param_substs: empty_substs
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};
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visit_mir_and_promoted(visitor, &mir);
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}
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TransItem::Fn(instance) => {
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// Keep track of the monomorphization recursion depth
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recursion_depth_reset = Some(check_recursion_limit(scx.tcx(),
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instance,
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recursion_depths));
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// Scan the MIR in order to find function calls, closures, and
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// drop-glue
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let mir = scx.tcx().item_mir(instance.def);
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let visitor = MirNeighborCollector {
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scx: scx,
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mir: &mir,
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output: &mut neighbors,
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param_substs: instance.substs
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};
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visit_mir_and_promoted(visitor, &mir);
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}
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}
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record_inlining_canditates(scx.tcx(), starting_point, &neighbors[..], inlining_map);
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for neighbour in neighbors {
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collect_items_rec(scx, neighbour, visited, recursion_depths, inlining_map);
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}
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if let Some((def_id, depth)) = recursion_depth_reset {
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recursion_depths.insert(def_id, depth);
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}
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debug!("END collect_items_rec({})", starting_point.to_string(scx.tcx()));
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}
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fn record_inlining_canditates<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
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caller: TransItem<'tcx>,
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callees: &[TransItem<'tcx>],
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inlining_map: &mut InliningMap<'tcx>) {
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let is_inlining_candidate = |trans_item: &TransItem<'tcx>| {
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trans_item.needs_local_copy(tcx)
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};
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let inlining_candidates = callees.into_iter()
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.map(|x| *x)
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.filter(is_inlining_candidate);
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inlining_map.record_inlining_canditates(caller, inlining_candidates);
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}
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fn check_recursion_limit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
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instance: Instance<'tcx>,
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recursion_depths: &mut DefIdMap<usize>)
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-> (DefId, usize) {
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let recursion_depth = recursion_depths.get(&instance.def)
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.map(|x| *x)
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.unwrap_or(0);
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debug!(" => recursion depth={}", recursion_depth);
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// Code that needs to instantiate the same function recursively
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// more than the recursion limit is assumed to be causing an
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// infinite expansion.
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if recursion_depth > tcx.sess.recursion_limit.get() {
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let error = format!("reached the recursion limit while instantiating `{}`",
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instance);
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if let Some(node_id) = tcx.map.as_local_node_id(instance.def) {
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tcx.sess.span_fatal(tcx.map.span(node_id), &error);
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} else {
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tcx.sess.fatal(&error);
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}
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}
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recursion_depths.insert(instance.def, recursion_depth + 1);
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(instance.def, recursion_depth)
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}
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struct MirNeighborCollector<'a, 'tcx: 'a> {
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scx: &'a SharedCrateContext<'a, 'tcx>,
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mir: &'a mir::Mir<'tcx>,
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output: &'a mut Vec<TransItem<'tcx>>,
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param_substs: &'tcx Substs<'tcx>
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}
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impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
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fn visit_rvalue(&mut self, rvalue: &mir::Rvalue<'tcx>, location: Location) {
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debug!("visiting rvalue {:?}", *rvalue);
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match *rvalue {
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mir::Rvalue::Aggregate(mir::AggregateKind::Closure(def_id,
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ref substs), _) => {
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let mir = self.scx.tcx().item_mir(def_id);
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let concrete_substs = monomorphize::apply_param_substs(self.scx,
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self.param_substs,
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&substs.func_substs);
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let concrete_substs = self.scx.tcx().erase_regions(&concrete_substs);
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let visitor = MirNeighborCollector {
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scx: self.scx,
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mir: &mir,
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output: self.output,
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param_substs: concrete_substs
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};
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visit_mir_and_promoted(visitor, &mir);
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}
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// When doing an cast from a regular pointer to a fat pointer, we
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// have to instantiate all methods of the trait being cast to, so we
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// can build the appropriate vtable.
|
|
mir::Rvalue::Cast(mir::CastKind::Unsize, ref operand, target_ty) => {
|
|
let target_ty = monomorphize::apply_param_substs(self.scx,
|
|
self.param_substs,
|
|
&target_ty);
|
|
let source_ty = operand.ty(self.mir, self.scx.tcx());
|
|
let source_ty = monomorphize::apply_param_substs(self.scx,
|
|
self.param_substs,
|
|
&source_ty);
|
|
let (source_ty, target_ty) = find_vtable_types_for_unsizing(self.scx,
|
|
source_ty,
|
|
target_ty);
|
|
// This could also be a different Unsize instruction, like
|
|
// from a fixed sized array to a slice. But we are only
|
|
// interested in things that produce a vtable.
|
|
if target_ty.is_trait() && !source_ty.is_trait() {
|
|
create_trans_items_for_vtable_methods(self.scx,
|
|
target_ty,
|
|
source_ty,
|
|
self.output);
|
|
}
|
|
}
|
|
mir::Rvalue::Box(..) => {
|
|
let exchange_malloc_fn_def_id =
|
|
self.scx
|
|
.tcx()
|
|
.lang_items
|
|
.require(ExchangeMallocFnLangItem)
|
|
.unwrap_or_else(|e| self.scx.sess().fatal(&e));
|
|
|
|
assert!(can_have_local_instance(self.scx.tcx(), exchange_malloc_fn_def_id));
|
|
let empty_substs = self.scx.empty_substs_for_def_id(exchange_malloc_fn_def_id);
|
|
let exchange_malloc_fn_trans_item =
|
|
create_fn_trans_item(self.scx,
|
|
exchange_malloc_fn_def_id,
|
|
empty_substs,
|
|
self.param_substs);
|
|
|
|
self.output.push(exchange_malloc_fn_trans_item);
|
|
}
|
|
_ => { /* not interesting */ }
|
|
}
|
|
|
|
self.super_rvalue(rvalue, location);
|
|
}
|
|
|
|
fn visit_lvalue(&mut self,
|
|
lvalue: &mir::Lvalue<'tcx>,
|
|
context: mir_visit::LvalueContext<'tcx>,
|
|
location: Location) {
|
|
debug!("visiting lvalue {:?}", *lvalue);
|
|
|
|
if let mir_visit::LvalueContext::Drop = context {
|
|
let ty = lvalue.ty(self.mir, self.scx.tcx())
|
|
.to_ty(self.scx.tcx());
|
|
|
|
let ty = monomorphize::apply_param_substs(self.scx,
|
|
self.param_substs,
|
|
&ty);
|
|
assert!(ty.is_normalized_for_trans());
|
|
let ty = glue::get_drop_glue_type(self.scx.tcx(), ty);
|
|
self.output.push(TransItem::DropGlue(DropGlueKind::Ty(ty)));
|
|
}
|
|
|
|
self.super_lvalue(lvalue, context, location);
|
|
}
|
|
|
|
fn visit_operand(&mut self, operand: &mir::Operand<'tcx>, location: Location) {
|
|
debug!("visiting operand {:?}", *operand);
|
|
|
|
let callee = match *operand {
|
|
mir::Operand::Constant(ref constant) => {
|
|
if let ty::TyFnDef(def_id, substs, _) = constant.ty.sty {
|
|
// This is something that can act as a callee, proceed
|
|
Some((def_id, substs))
|
|
} else {
|
|
// This is not a callee, but we still have to look for
|
|
// references to `const` items
|
|
if let mir::Literal::Item { def_id, substs } = constant.literal {
|
|
let tcx = self.scx.tcx();
|
|
let substs = monomorphize::apply_param_substs(self.scx,
|
|
self.param_substs,
|
|
&substs);
|
|
|
|
// If the constant referred to here is an associated
|
|
// item of a trait, we need to resolve it to the actual
|
|
// constant in the corresponding impl. Luckily
|
|
// const_eval::lookup_const_by_id() does that for us.
|
|
if let Some((expr, _)) = const_eval::lookup_const_by_id(tcx,
|
|
def_id,
|
|
Some(substs)) {
|
|
// The hir::Expr we get here is the initializer of
|
|
// the constant, what we really want is the item
|
|
// DefId.
|
|
let const_node_id = tcx.map.get_parent(expr.id);
|
|
let def_id = if tcx.map.is_inlined_node_id(const_node_id) {
|
|
tcx.sess.cstore.defid_for_inlined_node(const_node_id).unwrap()
|
|
} else {
|
|
tcx.map.local_def_id(const_node_id)
|
|
};
|
|
|
|
collect_const_item_neighbours(self.scx,
|
|
def_id,
|
|
substs,
|
|
self.output);
|
|
}
|
|
}
|
|
|
|
None
|
|
}
|
|
}
|
|
_ => None
|
|
};
|
|
|
|
if let Some((callee_def_id, callee_substs)) = callee {
|
|
debug!(" => operand is callable");
|
|
|
|
// `callee_def_id` might refer to a trait method instead of a
|
|
// concrete implementation, so we have to find the actual
|
|
// implementation. For example, the call might look like
|
|
//
|
|
// std::cmp::partial_cmp(0i32, 1i32)
|
|
//
|
|
// Calling do_static_dispatch() here will map the def_id of
|
|
// `std::cmp::partial_cmp` to the def_id of `i32::partial_cmp<i32>`
|
|
let dispatched = do_static_dispatch(self.scx,
|
|
callee_def_id,
|
|
callee_substs,
|
|
self.param_substs);
|
|
|
|
if let Some((callee_def_id, callee_substs)) = dispatched {
|
|
// if we have a concrete impl (which we might not have
|
|
// in the case of something compiler generated like an
|
|
// object shim or a closure that is handled differently),
|
|
// we check if the callee is something that will actually
|
|
// result in a translation item ...
|
|
if can_result_in_trans_item(self.scx.tcx(), callee_def_id) {
|
|
// ... and create one if it does.
|
|
let trans_item = create_fn_trans_item(self.scx,
|
|
callee_def_id,
|
|
callee_substs,
|
|
self.param_substs);
|
|
self.output.push(trans_item);
|
|
}
|
|
}
|
|
}
|
|
|
|
self.super_operand(operand, location);
|
|
|
|
fn can_result_in_trans_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
|
def_id: DefId)
|
|
-> bool {
|
|
match tcx.lookup_item_type(def_id).ty.sty {
|
|
ty::TyFnDef(def_id, _, f) => {
|
|
// Some constructors also have type TyFnDef but they are
|
|
// always instantiated inline and don't result in
|
|
// translation item. Same for FFI functions.
|
|
if let Some(hir_map::NodeForeignItem(_)) = tcx.map.get_if_local(def_id) {
|
|
return false;
|
|
}
|
|
|
|
if let Some(adt_def) = f.sig.output().skip_binder().ty_adt_def() {
|
|
if adt_def.variants.iter().any(|v| def_id == v.did) {
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
ty::TyClosure(..) => {}
|
|
_ => return false
|
|
}
|
|
|
|
can_have_local_instance(tcx, def_id)
|
|
}
|
|
}
|
|
|
|
// This takes care of the "drop_in_place" intrinsic for which we otherwise
|
|
// we would not register drop-glues.
|
|
fn visit_terminator_kind(&mut self,
|
|
block: mir::BasicBlock,
|
|
kind: &mir::TerminatorKind<'tcx>,
|
|
location: Location) {
|
|
let tcx = self.scx.tcx();
|
|
match *kind {
|
|
mir::TerminatorKind::Call {
|
|
func: mir::Operand::Constant(ref constant),
|
|
ref args,
|
|
..
|
|
} => {
|
|
match constant.ty.sty {
|
|
ty::TyFnDef(def_id, _, bare_fn_ty)
|
|
if is_drop_in_place_intrinsic(tcx, def_id, bare_fn_ty) => {
|
|
let operand_ty = args[0].ty(self.mir, tcx);
|
|
if let ty::TyRawPtr(mt) = operand_ty.sty {
|
|
let operand_ty = monomorphize::apply_param_substs(self.scx,
|
|
self.param_substs,
|
|
&mt.ty);
|
|
let ty = glue::get_drop_glue_type(tcx, operand_ty);
|
|
self.output.push(TransItem::DropGlue(DropGlueKind::Ty(ty)));
|
|
} else {
|
|
bug!("Has the drop_in_place() intrinsic's signature changed?")
|
|
}
|
|
}
|
|
_ => { /* Nothing to do. */ }
|
|
}
|
|
}
|
|
_ => { /* Nothing to do. */ }
|
|
}
|
|
|
|
self.super_terminator_kind(block, kind, location);
|
|
|
|
fn is_drop_in_place_intrinsic<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
|
def_id: DefId,
|
|
bare_fn_ty: &ty::BareFnTy<'tcx>)
|
|
-> bool {
|
|
(bare_fn_ty.abi == Abi::RustIntrinsic ||
|
|
bare_fn_ty.abi == Abi::PlatformIntrinsic) &&
|
|
tcx.item_name(def_id).as_str() == "drop_in_place"
|
|
}
|
|
}
|
|
}
|
|
|
|
fn can_have_local_instance<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
|
def_id: DefId)
|
|
-> bool {
|
|
// Take a look if we have the definition available. If not, we
|
|
// will not emit code for this item in the local crate, and thus
|
|
// don't create a translation item for it.
|
|
def_id.is_local() || tcx.sess.cstore.is_item_mir_available(def_id)
|
|
}
|
|
|
|
fn find_drop_glue_neighbors<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
|
|
dg: DropGlueKind<'tcx>,
|
|
output: &mut Vec<TransItem<'tcx>>) {
|
|
let ty = match dg {
|
|
DropGlueKind::Ty(ty) => ty,
|
|
DropGlueKind::TyContents(_) => {
|
|
// We already collected the neighbors of this item via the
|
|
// DropGlueKind::Ty variant.
|
|
return
|
|
}
|
|
};
|
|
|
|
debug!("find_drop_glue_neighbors: {}", type_to_string(scx.tcx(), ty));
|
|
|
|
// Make sure the exchange_free_fn() lang-item gets translated if
|
|
// there is a boxed value.
|
|
if let ty::TyBox(_) = ty.sty {
|
|
let exchange_free_fn_def_id = scx.tcx()
|
|
.lang_items
|
|
.require(ExchangeFreeFnLangItem)
|
|
.unwrap_or_else(|e| scx.sess().fatal(&e));
|
|
|
|
assert!(can_have_local_instance(scx.tcx(), exchange_free_fn_def_id));
|
|
let fn_substs = scx.empty_substs_for_def_id(exchange_free_fn_def_id);
|
|
let exchange_free_fn_trans_item =
|
|
create_fn_trans_item(scx,
|
|
exchange_free_fn_def_id,
|
|
fn_substs,
|
|
scx.tcx().intern_substs(&[]));
|
|
|
|
output.push(exchange_free_fn_trans_item);
|
|
}
|
|
|
|
// If the type implements Drop, also add a translation item for the
|
|
// monomorphized Drop::drop() implementation.
|
|
let destructor_did = match ty.sty {
|
|
ty::TyAdt(def, _) => def.destructor(),
|
|
_ => None
|
|
};
|
|
|
|
if let Some(destructor_did) = destructor_did {
|
|
use rustc::ty::ToPolyTraitRef;
|
|
|
|
let drop_trait_def_id = scx.tcx()
|
|
.lang_items
|
|
.drop_trait()
|
|
.unwrap();
|
|
|
|
let self_type_substs = scx.tcx().mk_substs_trait(ty, &[]);
|
|
|
|
let trait_ref = ty::TraitRef {
|
|
def_id: drop_trait_def_id,
|
|
substs: self_type_substs,
|
|
}.to_poly_trait_ref();
|
|
|
|
let substs = match fulfill_obligation(scx, DUMMY_SP, trait_ref) {
|
|
traits::VtableImpl(data) => data.substs,
|
|
_ => bug!()
|
|
};
|
|
|
|
if can_have_local_instance(scx.tcx(), destructor_did) {
|
|
let trans_item = create_fn_trans_item(scx,
|
|
destructor_did,
|
|
substs,
|
|
scx.tcx().intern_substs(&[]));
|
|
output.push(trans_item);
|
|
}
|
|
|
|
// This type has a Drop implementation, we'll need the contents-only
|
|
// version of the glue too.
|
|
output.push(TransItem::DropGlue(DropGlueKind::TyContents(ty)));
|
|
}
|
|
|
|
// Finally add the types of nested values
|
|
match ty.sty {
|
|
ty::TyBool |
|
|
ty::TyChar |
|
|
ty::TyInt(_) |
|
|
ty::TyUint(_) |
|
|
ty::TyStr |
|
|
ty::TyFloat(_) |
|
|
ty::TyRawPtr(_) |
|
|
ty::TyRef(..) |
|
|
ty::TyFnDef(..) |
|
|
ty::TyFnPtr(_) |
|
|
ty::TyNever |
|
|
ty::TyTrait(_) => {
|
|
/* nothing to do */
|
|
}
|
|
ty::TyAdt(adt_def, substs) => {
|
|
for field in adt_def.all_fields() {
|
|
let field_type = monomorphize::apply_param_substs(scx,
|
|
substs,
|
|
&field.unsubst_ty());
|
|
let field_type = glue::get_drop_glue_type(scx.tcx(), field_type);
|
|
|
|
if glue::type_needs_drop(scx.tcx(), field_type) {
|
|
output.push(TransItem::DropGlue(DropGlueKind::Ty(field_type)));
|
|
}
|
|
}
|
|
}
|
|
ty::TyClosure(_, substs) => {
|
|
for upvar_ty in substs.upvar_tys {
|
|
let upvar_ty = glue::get_drop_glue_type(scx.tcx(), upvar_ty);
|
|
if glue::type_needs_drop(scx.tcx(), upvar_ty) {
|
|
output.push(TransItem::DropGlue(DropGlueKind::Ty(upvar_ty)));
|
|
}
|
|
}
|
|
}
|
|
ty::TyBox(inner_type) |
|
|
ty::TySlice(inner_type) |
|
|
ty::TyArray(inner_type, _) => {
|
|
let inner_type = glue::get_drop_glue_type(scx.tcx(), inner_type);
|
|
if glue::type_needs_drop(scx.tcx(), inner_type) {
|
|
output.push(TransItem::DropGlue(DropGlueKind::Ty(inner_type)));
|
|
}
|
|
}
|
|
ty::TyTuple(args) => {
|
|
for arg in args {
|
|
let arg = glue::get_drop_glue_type(scx.tcx(), arg);
|
|
if glue::type_needs_drop(scx.tcx(), arg) {
|
|
output.push(TransItem::DropGlue(DropGlueKind::Ty(arg)));
|
|
}
|
|
}
|
|
}
|
|
ty::TyProjection(_) |
|
|
ty::TyParam(_) |
|
|
ty::TyInfer(_) |
|
|
ty::TyAnon(..) |
|
|
ty::TyError => {
|
|
bug!("encountered unexpected type");
|
|
}
|
|
}
|
|
|
|
|
|
}
|
|
|
|
fn do_static_dispatch<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
|
|
fn_def_id: DefId,
|
|
fn_substs: &'tcx Substs<'tcx>,
|
|
param_substs: &'tcx Substs<'tcx>)
|
|
-> Option<(DefId, &'tcx Substs<'tcx>)> {
|
|
debug!("do_static_dispatch(fn_def_id={}, fn_substs={:?}, param_substs={:?})",
|
|
def_id_to_string(scx.tcx(), fn_def_id),
|
|
fn_substs,
|
|
param_substs);
|
|
|
|
if let Some(trait_def_id) = scx.tcx().trait_of_item(fn_def_id) {
|
|
match scx.tcx().impl_or_trait_item(fn_def_id) {
|
|
ty::MethodTraitItem(ref method) => {
|
|
debug!(" => trait method, attempting to find impl");
|
|
do_static_trait_method_dispatch(scx,
|
|
method,
|
|
trait_def_id,
|
|
fn_substs,
|
|
param_substs)
|
|
}
|
|
_ => bug!()
|
|
}
|
|
} else {
|
|
debug!(" => regular function");
|
|
// The function is not part of an impl or trait, no dispatching
|
|
// to be done
|
|
Some((fn_def_id, fn_substs))
|
|
}
|
|
}
|
|
|
|
// Given a trait-method and substitution information, find out the actual
|
|
// implementation of the trait method.
|
|
fn do_static_trait_method_dispatch<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
|
|
trait_method: &ty::Method,
|
|
trait_id: DefId,
|
|
callee_substs: &'tcx Substs<'tcx>,
|
|
param_substs: &'tcx Substs<'tcx>)
|
|
-> Option<(DefId, &'tcx Substs<'tcx>)> {
|
|
let tcx = scx.tcx();
|
|
debug!("do_static_trait_method_dispatch(trait_method={}, \
|
|
trait_id={}, \
|
|
callee_substs={:?}, \
|
|
param_substs={:?}",
|
|
def_id_to_string(scx.tcx(), trait_method.def_id),
|
|
def_id_to_string(scx.tcx(), trait_id),
|
|
callee_substs,
|
|
param_substs);
|
|
|
|
let rcvr_substs = monomorphize::apply_param_substs(scx,
|
|
param_substs,
|
|
&callee_substs);
|
|
let trait_ref = ty::TraitRef::from_method(tcx, trait_id, rcvr_substs);
|
|
let vtbl = fulfill_obligation(scx, DUMMY_SP, ty::Binder(trait_ref));
|
|
|
|
// Now that we know which impl is being used, we can dispatch to
|
|
// the actual function:
|
|
match vtbl {
|
|
traits::VtableImpl(impl_data) => {
|
|
Some(traits::find_method(tcx, trait_method.name, rcvr_substs, &impl_data))
|
|
}
|
|
// If we have a closure or a function pointer, we will also encounter
|
|
// the concrete closure/function somewhere else (during closure or fn
|
|
// pointer construction). That's where we track those things.
|
|
traits::VtableClosure(..) |
|
|
traits::VtableFnPointer(..) |
|
|
traits::VtableObject(..) => {
|
|
None
|
|
}
|
|
_ => {
|
|
bug!("static call to invalid vtable: {:?}", vtbl)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// For given pair of source and target type that occur in an unsizing coercion,
|
|
/// this function finds the pair of types that determines the vtable linking
|
|
/// them.
|
|
///
|
|
/// For example, the source type might be `&SomeStruct` and the target type\
|
|
/// might be `&SomeTrait` in a cast like:
|
|
///
|
|
/// let src: &SomeStruct = ...;
|
|
/// let target = src as &SomeTrait;
|
|
///
|
|
/// Then the output of this function would be (SomeStruct, SomeTrait) since for
|
|
/// constructing the `target` fat-pointer we need the vtable for that pair.
|
|
///
|
|
/// Things can get more complicated though because there's also the case where
|
|
/// the unsized type occurs as a field:
|
|
///
|
|
/// ```rust
|
|
/// struct ComplexStruct<T: ?Sized> {
|
|
/// a: u32,
|
|
/// b: f64,
|
|
/// c: T
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// In this case, if `T` is sized, `&ComplexStruct<T>` is a thin pointer. If `T`
|
|
/// is unsized, `&SomeStruct` is a fat pointer, and the vtable it points to is
|
|
/// for the pair of `T` (which is a trait) and the concrete type that `T` was
|
|
/// originally coerced from:
|
|
///
|
|
/// let src: &ComplexStruct<SomeStruct> = ...;
|
|
/// let target = src as &ComplexStruct<SomeTrait>;
|
|
///
|
|
/// Again, we want this `find_vtable_types_for_unsizing()` to provide the pair
|
|
/// `(SomeStruct, SomeTrait)`.
|
|
///
|
|
/// Finally, there is also the case of custom unsizing coercions, e.g. for
|
|
/// smart pointers such as `Rc` and `Arc`.
|
|
fn find_vtable_types_for_unsizing<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
|
|
source_ty: ty::Ty<'tcx>,
|
|
target_ty: ty::Ty<'tcx>)
|
|
-> (ty::Ty<'tcx>, ty::Ty<'tcx>) {
|
|
match (&source_ty.sty, &target_ty.sty) {
|
|
(&ty::TyBox(a), &ty::TyBox(b)) |
|
|
(&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
|
|
&ty::TyRef(_, ty::TypeAndMut { ty: b, .. })) |
|
|
(&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
|
|
&ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) |
|
|
(&ty::TyRawPtr(ty::TypeAndMut { ty: a, .. }),
|
|
&ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) => {
|
|
let (inner_source, inner_target) = (a, b);
|
|
|
|
if !type_is_sized(scx.tcx(), inner_source) {
|
|
(inner_source, inner_target)
|
|
} else {
|
|
scx.tcx().struct_lockstep_tails(inner_source, inner_target)
|
|
}
|
|
}
|
|
|
|
(&ty::TyAdt(source_adt_def, source_substs),
|
|
&ty::TyAdt(target_adt_def, target_substs)) => {
|
|
assert_eq!(source_adt_def, target_adt_def);
|
|
|
|
let kind = custom_coerce_unsize_info(scx, source_ty, target_ty);
|
|
|
|
let coerce_index = match kind {
|
|
CustomCoerceUnsized::Struct(i) => i
|
|
};
|
|
|
|
let source_fields = &source_adt_def.struct_variant().fields;
|
|
let target_fields = &target_adt_def.struct_variant().fields;
|
|
|
|
assert!(coerce_index < source_fields.len() &&
|
|
source_fields.len() == target_fields.len());
|
|
|
|
find_vtable_types_for_unsizing(scx,
|
|
source_fields[coerce_index].ty(scx.tcx(),
|
|
source_substs),
|
|
target_fields[coerce_index].ty(scx.tcx(),
|
|
target_substs))
|
|
}
|
|
_ => bug!("find_vtable_types_for_unsizing: invalid coercion {:?} -> {:?}",
|
|
source_ty,
|
|
target_ty)
|
|
}
|
|
}
|
|
|
|
fn create_fn_trans_item<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
|
|
def_id: DefId,
|
|
fn_substs: &'tcx Substs<'tcx>,
|
|
param_substs: &'tcx Substs<'tcx>)
|
|
-> TransItem<'tcx> {
|
|
let tcx = scx.tcx();
|
|
|
|
debug!("create_fn_trans_item(def_id={}, fn_substs={:?}, param_substs={:?})",
|
|
def_id_to_string(tcx, def_id),
|
|
fn_substs,
|
|
param_substs);
|
|
|
|
// We only get here, if fn_def_id either designates a local item or
|
|
// an inlineable external item. Non-inlineable external items are
|
|
// ignored because we don't want to generate any code for them.
|
|
let concrete_substs = monomorphize::apply_param_substs(scx,
|
|
param_substs,
|
|
&fn_substs);
|
|
assert!(concrete_substs.is_normalized_for_trans(),
|
|
"concrete_substs not normalized for trans: {:?}",
|
|
concrete_substs);
|
|
TransItem::Fn(Instance::new(def_id, concrete_substs))
|
|
}
|
|
|
|
/// Creates a `TransItem` for each method that is referenced by the vtable for
|
|
/// the given trait/impl pair.
|
|
fn create_trans_items_for_vtable_methods<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
|
|
trait_ty: ty::Ty<'tcx>,
|
|
impl_ty: ty::Ty<'tcx>,
|
|
output: &mut Vec<TransItem<'tcx>>) {
|
|
assert!(!trait_ty.needs_subst() && !impl_ty.needs_subst());
|
|
|
|
if let ty::TyTrait(ref trait_ty) = trait_ty.sty {
|
|
let poly_trait_ref = trait_ty.principal.with_self_ty(scx.tcx(), impl_ty);
|
|
let param_substs = scx.tcx().intern_substs(&[]);
|
|
|
|
// Walk all methods of the trait, including those of its supertraits
|
|
let methods = traits::get_vtable_methods(scx.tcx(), poly_trait_ref);
|
|
let methods = methods.filter_map(|method| method)
|
|
.filter_map(|(def_id, substs)| do_static_dispatch(scx, def_id, substs, param_substs))
|
|
.filter(|&(def_id, _)| can_have_local_instance(scx.tcx(), def_id))
|
|
.map(|(def_id, substs)| create_fn_trans_item(scx, def_id, substs, param_substs));
|
|
output.extend(methods);
|
|
|
|
// Also add the destructor
|
|
let dg_type = glue::get_drop_glue_type(scx.tcx(), impl_ty);
|
|
output.push(TransItem::DropGlue(DropGlueKind::Ty(dg_type)));
|
|
}
|
|
}
|
|
|
|
//=-----------------------------------------------------------------------------
|
|
// Root Collection
|
|
//=-----------------------------------------------------------------------------
|
|
|
|
struct RootCollector<'b, 'a: 'b, 'tcx: 'a + 'b> {
|
|
scx: &'b SharedCrateContext<'a, 'tcx>,
|
|
mode: TransItemCollectionMode,
|
|
output: &'b mut Vec<TransItem<'tcx>>,
|
|
enclosing_item: Option<&'tcx hir::Item>,
|
|
}
|
|
|
|
impl<'b, 'a, 'v> hir_visit::Visitor<'v> for RootCollector<'b, 'a, 'v> {
|
|
fn visit_item(&mut self, item: &'v hir::Item) {
|
|
let old_enclosing_item = self.enclosing_item;
|
|
self.enclosing_item = Some(item);
|
|
|
|
match item.node {
|
|
hir::ItemExternCrate(..) |
|
|
hir::ItemUse(..) |
|
|
hir::ItemForeignMod(..) |
|
|
hir::ItemTy(..) |
|
|
hir::ItemDefaultImpl(..) |
|
|
hir::ItemTrait(..) |
|
|
hir::ItemMod(..) => {
|
|
// Nothing to do, just keep recursing...
|
|
}
|
|
|
|
hir::ItemImpl(..) => {
|
|
if self.mode == TransItemCollectionMode::Eager {
|
|
create_trans_items_for_default_impls(self.scx,
|
|
item,
|
|
self.output);
|
|
}
|
|
}
|
|
|
|
hir::ItemEnum(_, ref generics) |
|
|
hir::ItemStruct(_, ref generics) |
|
|
hir::ItemUnion(_, ref generics) => {
|
|
if !generics.is_parameterized() {
|
|
let ty = {
|
|
let tables = self.scx.tcx().tables.borrow();
|
|
tables.node_types[&item.id]
|
|
};
|
|
|
|
if self.mode == TransItemCollectionMode::Eager {
|
|
debug!("RootCollector: ADT drop-glue for {}",
|
|
def_id_to_string(self.scx.tcx(),
|
|
self.scx.tcx().map.local_def_id(item.id)));
|
|
|
|
let ty = glue::get_drop_glue_type(self.scx.tcx(), ty);
|
|
self.output.push(TransItem::DropGlue(DropGlueKind::Ty(ty)));
|
|
}
|
|
}
|
|
}
|
|
hir::ItemStatic(..) => {
|
|
debug!("RootCollector: ItemStatic({})",
|
|
def_id_to_string(self.scx.tcx(),
|
|
self.scx.tcx().map.local_def_id(item.id)));
|
|
self.output.push(TransItem::Static(item.id));
|
|
}
|
|
hir::ItemConst(..) => {
|
|
// const items only generate translation items if they are
|
|
// actually used somewhere. Just declaring them is insufficient.
|
|
}
|
|
hir::ItemFn(.., ref generics, _) => {
|
|
if !generics.is_type_parameterized() {
|
|
let def_id = self.scx.tcx().map.local_def_id(item.id);
|
|
|
|
debug!("RootCollector: ItemFn({})",
|
|
def_id_to_string(self.scx.tcx(), def_id));
|
|
|
|
let instance = Instance::mono(self.scx, def_id);
|
|
self.output.push(TransItem::Fn(instance));
|
|
}
|
|
}
|
|
}
|
|
|
|
hir_visit::walk_item(self, item);
|
|
self.enclosing_item = old_enclosing_item;
|
|
}
|
|
|
|
fn visit_impl_item(&mut self, ii: &'v hir::ImplItem) {
|
|
match ii.node {
|
|
hir::ImplItemKind::Method(hir::MethodSig {
|
|
ref generics,
|
|
..
|
|
}, _) => {
|
|
let hir_map = &self.scx.tcx().map;
|
|
let parent_node_id = hir_map.get_parent_node(ii.id);
|
|
let is_impl_generic = match hir_map.expect_item(parent_node_id) {
|
|
&hir::Item {
|
|
node: hir::ItemImpl(_, _, ref generics, ..),
|
|
..
|
|
} => {
|
|
generics.is_type_parameterized()
|
|
}
|
|
_ => {
|
|
bug!()
|
|
}
|
|
};
|
|
|
|
if !generics.is_type_parameterized() && !is_impl_generic {
|
|
let def_id = self.scx.tcx().map.local_def_id(ii.id);
|
|
|
|
debug!("RootCollector: MethodImplItem({})",
|
|
def_id_to_string(self.scx.tcx(), def_id));
|
|
|
|
let instance = Instance::mono(self.scx, def_id);
|
|
self.output.push(TransItem::Fn(instance));
|
|
}
|
|
}
|
|
_ => { /* Nothing to do here */ }
|
|
}
|
|
|
|
hir_visit::walk_impl_item(self, ii)
|
|
}
|
|
}
|
|
|
|
fn create_trans_items_for_default_impls<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
|
|
item: &'tcx hir::Item,
|
|
output: &mut Vec<TransItem<'tcx>>) {
|
|
let tcx = scx.tcx();
|
|
match item.node {
|
|
hir::ItemImpl(_,
|
|
_,
|
|
ref generics,
|
|
..,
|
|
ref items) => {
|
|
if generics.is_type_parameterized() {
|
|
return
|
|
}
|
|
|
|
let impl_def_id = tcx.map.local_def_id(item.id);
|
|
|
|
debug!("create_trans_items_for_default_impls(item={})",
|
|
def_id_to_string(tcx, impl_def_id));
|
|
|
|
if let Some(trait_ref) = tcx.impl_trait_ref(impl_def_id) {
|
|
let callee_substs = tcx.erase_regions(&trait_ref.substs);
|
|
let overridden_methods: FnvHashSet<_> = items.iter()
|
|
.map(|item| item.name)
|
|
.collect();
|
|
for method in tcx.provided_trait_methods(trait_ref.def_id) {
|
|
if overridden_methods.contains(&method.name) {
|
|
continue;
|
|
}
|
|
|
|
if !method.generics.types.is_empty() {
|
|
continue;
|
|
}
|
|
|
|
// The substitutions we have are on the impl, so we grab
|
|
// the method type from the impl to substitute into.
|
|
let impl_substs = Substs::for_item(tcx, impl_def_id,
|
|
|_, _| tcx.mk_region(ty::ReErased),
|
|
|_, _| tcx.types.err);
|
|
let impl_data = traits::VtableImplData {
|
|
impl_def_id: impl_def_id,
|
|
substs: impl_substs,
|
|
nested: vec![]
|
|
};
|
|
let (def_id, substs) = traits::find_method(tcx,
|
|
method.name,
|
|
callee_substs,
|
|
&impl_data);
|
|
|
|
let predicates = tcx.lookup_predicates(def_id).predicates
|
|
.subst(tcx, substs);
|
|
if !traits::normalize_and_test_predicates(tcx, predicates) {
|
|
continue;
|
|
}
|
|
|
|
if can_have_local_instance(tcx, method.def_id) {
|
|
let item = create_fn_trans_item(scx,
|
|
method.def_id,
|
|
callee_substs,
|
|
tcx.erase_regions(&substs));
|
|
output.push(item);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
_ => {
|
|
bug!()
|
|
}
|
|
}
|
|
}
|
|
|
|
// There are no translation items for constants themselves but their
|
|
// initializers might still contain something that produces translation items,
|
|
// such as cast that introduce a new vtable.
|
|
fn collect_const_item_neighbours<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
|
|
def_id: DefId,
|
|
substs: &'tcx Substs<'tcx>,
|
|
output: &mut Vec<TransItem<'tcx>>)
|
|
{
|
|
// Scan the MIR in order to find function calls, closures, and
|
|
// drop-glue
|
|
let mir = scx.tcx().item_mir(def_id);
|
|
|
|
let visitor = MirNeighborCollector {
|
|
scx: scx,
|
|
mir: &mir,
|
|
output: output,
|
|
param_substs: substs
|
|
};
|
|
|
|
visit_mir_and_promoted(visitor, &mir);
|
|
}
|
|
|
|
fn visit_mir_and_promoted<'tcx, V: MirVisitor<'tcx>>(mut visitor: V, mir: &mir::Mir<'tcx>) {
|
|
visitor.visit_mir(&mir);
|
|
for promoted in &mir.promoted {
|
|
visitor.visit_mir(promoted);
|
|
}
|
|
}
|