2253 lines
82 KiB
Rust
2253 lines
82 KiB
Rust
// Copyright 2012 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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/*!
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*
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* # Compilation of match statements
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*
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* I will endeavor to explain the code as best I can. I have only a loose
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* understanding of some parts of it.
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*
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* ## Matching
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*
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* The basic state of the code is maintained in an array `m` of `Match`
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* objects. Each `Match` describes some list of patterns, all of which must
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* match against the current list of values. If those patterns match, then
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* the arm listed in the match is the correct arm. A given arm may have
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* multiple corresponding match entries, one for each alternative that
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* remains. As we proceed these sets of matches are adjusted by the various
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* `enter_XXX()` functions, each of which adjusts the set of options given
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* some information about the value which has been matched.
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*
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* So, initially, there is one value and N matches, each of which have one
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* constituent pattern. N here is usually the number of arms but may be
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* greater, if some arms have multiple alternatives. For example, here:
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*
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* enum Foo { A, B(int), C(uint, uint) }
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* match foo {
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* A => ...,
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* B(x) => ...,
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* C(1u, 2) => ...,
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* C(_) => ...
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* }
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*
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* The value would be `foo`. There would be four matches, each of which
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* contains one pattern (and, in one case, a guard). We could collect the
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* various options and then compile the code for the case where `foo` is an
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* `A`, a `B`, and a `C`. When we generate the code for `C`, we would (1)
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* drop the two matches that do not match a `C` and (2) expand the other two
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* into two patterns each. In the first case, the two patterns would be `1u`
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* and `2`, and the in the second case the _ pattern would be expanded into
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* `_` and `_`. The two values are of course the arguments to `C`.
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*
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* Here is a quick guide to the various functions:
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*
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* - `compile_submatch()`: The main workhouse. It takes a list of values and
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* a list of matches and finds the various possibilities that could occur.
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*
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* - `enter_XXX()`: modifies the list of matches based on some information
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* about the value that has been matched. For example,
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* `enter_rec_or_struct()` adjusts the values given that a record or struct
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* has been matched. This is an infallible pattern, so *all* of the matches
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* must be either wildcards or record/struct patterns. `enter_opt()`
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* handles the fallible cases, and it is correspondingly more complex.
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*
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* ## Bindings
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*
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* We store information about the bound variables for each arm as part of the
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* per-arm `ArmData` struct. There is a mapping from identifiers to
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* `BindingInfo` structs. These structs contain the mode/id/type of the
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* binding, but they also contain up to two LLVM values, called `llmatch` and
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* `llbinding` respectively (the `llbinding`, as will be described shortly, is
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* optional and only present for by-value bindings---therefore it is bundled
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* up as part of the `TransBindingMode` type). Both point at allocas.
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*
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* The `llmatch` binding always stores a pointer into the value being matched
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* which points at the data for the binding. If the value being matched has
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* type `T`, then, `llmatch` will point at an alloca of type `T*` (and hence
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* `llmatch` has type `T**`). So, if you have a pattern like:
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*
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* let a: A = ...;
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* let b: B = ...;
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* match (a, b) { (ref c, d) => { ... } }
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*
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* For `c` and `d`, we would generate allocas of type `C*` and `D*`
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* respectively. These are called the `llmatch`. As we match, when we come
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* up against an identifier, we store the current pointer into the
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* corresponding alloca.
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*
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* In addition, for each by-value binding (copy or move), we will create a
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* second alloca (`llbinding`) that will hold the final value. In this
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* example, that means that `d` would have this second alloca of type `D` (and
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* hence `llbinding` has type `D*`).
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*
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* Once a pattern is completely matched, and assuming that there is no guard
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* pattern, we will branch to a block that leads to the body itself. For any
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* by-value bindings, this block will first load the ptr from `llmatch` (the
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* one of type `D*`) and copy/move the value into `llbinding` (the one of type
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* `D`). The second alloca then becomes the value of the local variable. For
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* by ref bindings, the value of the local variable is simply the first
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* alloca.
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*
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* So, for the example above, we would generate a setup kind of like this:
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*
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* +-------+
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* | Entry |
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* +-------+
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* |
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* +-------------------------------------------+
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* | llmatch_c = (addr of first half of tuple) |
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* | llmatch_d = (addr of first half of tuple) |
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* +-------------------------------------------+
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* |
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* +--------------------------------------+
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* | *llbinding_d = **llmatch_dlbinding_d |
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* +--------------------------------------+
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*
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* If there is a guard, the situation is slightly different, because we must
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* execute the guard code. Moreover, we need to do so once for each of the
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* alternatives that lead to the arm, because if the guard fails, they may
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* have different points from which to continue the search. Therefore, in that
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* case, we generate code that looks more like:
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*
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* +-------+
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* | Entry |
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* +-------+
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* |
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* +-------------------------------------------+
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* | llmatch_c = (addr of first half of tuple) |
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* | llmatch_d = (addr of first half of tuple) |
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* +-------------------------------------------+
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* |
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* +-------------------------------------------------+
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* | *llbinding_d = **llmatch_dlbinding_d |
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* | check condition |
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* | if false { free *llbinding_d, goto next case } |
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* | if true { goto body } |
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* +-------------------------------------------------+
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*
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* The handling for the cleanups is a bit... sensitive. Basically, the body
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* is the one that invokes `add_clean()` for each binding. During the guard
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* evaluation, we add temporary cleanups and revoke them after the guard is
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* evaluated (it could fail, after all). Presuming the guard fails, we drop
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* the various values we copied explicitly. Note that guards and moves are
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* just plain incompatible.
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*
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* Some relevant helper functions that manage bindings:
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* - `create_bindings_map()`
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* - `store_non_ref_bindings()`
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* - `insert_lllocals()`
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*
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*
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* ## Notes on vector pattern matching.
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*
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* Vector pattern matching is surprisingly tricky. The problem is that
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* the structure of the vector isn't fully known, and slice matches
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* can be done on subparts of it.
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*
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* The way that vector pattern matches are dealt with, then, is as
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* follows. First, we make the actual condition associated with a
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* vector pattern simply a vector length comparison. So the pattern
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* [1, .. x] gets the condition "vec len >= 1", and the pattern
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* [.. x] gets the condition "vec len >= 0". The problem here is that
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* having the condition "vec len >= 1" hold clearly does not mean that
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* only a pattern that has exactly that condition will match. This
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* means that it may well be the case that a condition holds, but none
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* of the patterns matching that condition match; to deal with this,
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* when doing vector length matches, we have match failures proceed to
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* the next condition to check.
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*
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* There are a couple more subtleties to deal with. While the "actual"
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* condition associated with vector length tests is simply a test on
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* the vector length, the actual vec_len Opt entry contains more
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* information used to restrict which matches are associated with it.
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* So that all matches in a submatch are matching against the same
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* values from inside the vector, they are split up by how many
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* elements they match at the front and at the back of the vector. In
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* order to make sure that arms are properly checked in order, even
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* with the overmatching conditions, each vec_len Opt entry is
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* associated with a range of matches.
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* Consider the following:
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*
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* match &[1, 2, 3] {
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* [1, 1, .. _] => 0,
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* [1, 2, 2, .. _] => 1,
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* [1, 2, 3, .. _] => 2,
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* [1, 2, .. _] => 3,
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* _ => 4
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* }
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* The proper arm to match is arm 2, but arms 0 and 3 both have the
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* condition "len >= 2". If arm 3 was lumped in with arm 0, then the
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* wrong branch would be taken. Instead, vec_len Opts are associated
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* with a contiguous range of matches that have the same "shape".
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* This is sort of ugly and requires a bunch of special handling of
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* vec_len options.
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*
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*/
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use back::abi;
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use lib::llvm::{llvm, ValueRef, BasicBlockRef};
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use middle::const_eval;
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use middle::borrowck::root_map_key;
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use middle::lang_items::{UniqStrEqFnLangItem, StrEqFnLangItem};
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use middle::pat_util::*;
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use middle::resolve::DefMap;
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use middle::trans::adt;
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use middle::trans::base::*;
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use middle::trans::build::*;
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use middle::trans::callee;
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use middle::trans::common::*;
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use middle::trans::consts;
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use middle::trans::controlflow;
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use middle::trans::datum;
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use middle::trans::datum::*;
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use middle::trans::expr::Dest;
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use middle::trans::expr;
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use middle::trans::glue;
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use middle::trans::tvec;
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use middle::trans::type_of;
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use middle::trans::debuginfo;
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use middle::ty;
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use util::common::indenter;
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use util::ppaux::{Repr, vec_map_to_str};
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use std::hashmap::HashMap;
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use std::vec;
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use syntax::ast;
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use syntax::ast::Ident;
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use syntax::ast_util::path_to_ident;
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use syntax::ast_util;
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use syntax::codemap::{Span, dummy_sp};
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// An option identifying a literal: either a unit-like struct or an
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// expression.
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enum Lit {
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UnitLikeStructLit(ast::NodeId), // the node ID of the pattern
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ExprLit(@ast::Expr),
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ConstLit(ast::DefId), // the def ID of the constant
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}
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#[deriving(Eq)]
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pub enum VecLenOpt {
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vec_len_eq,
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vec_len_ge(/* length of prefix */uint)
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}
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// An option identifying a branch (either a literal, a enum variant or a
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// range)
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enum Opt {
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lit(Lit),
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var(ty::Disr, @adt::Repr),
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range(@ast::Expr, @ast::Expr),
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vec_len(/* length */ uint, VecLenOpt, /*range of matches*/(uint, uint))
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}
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fn opt_eq(tcx: ty::ctxt, a: &Opt, b: &Opt) -> bool {
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match (a, b) {
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(&lit(a), &lit(b)) => {
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match (a, b) {
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(UnitLikeStructLit(a), UnitLikeStructLit(b)) => a == b,
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_ => {
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let a_expr;
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match a {
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ExprLit(existing_a_expr) => a_expr = existing_a_expr,
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ConstLit(a_const) => {
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let e = const_eval::lookup_const_by_id(tcx, a_const);
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a_expr = e.unwrap();
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}
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UnitLikeStructLit(_) => {
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fail!("UnitLikeStructLit should have been handled \
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above")
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}
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}
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let b_expr;
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match b {
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ExprLit(existing_b_expr) => b_expr = existing_b_expr,
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ConstLit(b_const) => {
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let e = const_eval::lookup_const_by_id(tcx, b_const);
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b_expr = e.unwrap();
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}
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UnitLikeStructLit(_) => {
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fail!("UnitLikeStructLit should have been handled \
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above")
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}
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}
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match const_eval::compare_lit_exprs(tcx, a_expr, b_expr) {
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Some(val1) => val1 == 0,
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None => fail!("compare_list_exprs: type mismatch"),
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}
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}
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}
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}
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(&range(a1, a2), &range(b1, b2)) => {
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let m1 = const_eval::compare_lit_exprs(tcx, a1, b1);
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let m2 = const_eval::compare_lit_exprs(tcx, a2, b2);
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match (m1, m2) {
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(Some(val1), Some(val2)) => (val1 == 0 && val2 == 0),
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_ => fail!("compare_list_exprs: type mismatch"),
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}
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}
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(&var(a, _), &var(b, _)) => a == b,
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(&vec_len(a1, a2, _), &vec_len(b1, b2, _)) =>
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a1 == b1 && a2 == b2,
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_ => false
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}
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}
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pub enum opt_result {
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single_result(Result),
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lower_bound(Result),
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range_result(Result, Result),
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}
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fn trans_opt(bcx: @mut Block, o: &Opt) -> opt_result {
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let _icx = push_ctxt("match::trans_opt");
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let ccx = bcx.ccx();
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let bcx = bcx;
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match *o {
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lit(ExprLit(lit_expr)) => {
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let datumblock = expr::trans_to_datum(bcx, lit_expr);
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return single_result(datumblock.to_result());
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}
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lit(UnitLikeStructLit(pat_id)) => {
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let struct_ty = ty::node_id_to_type(bcx.tcx(), pat_id);
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let datumblock = datum::scratch_datum(bcx, struct_ty, "", true);
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return single_result(datumblock.to_result(bcx));
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}
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lit(ConstLit(lit_id)) => {
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let (llval, _) = consts::get_const_val(bcx.ccx(), lit_id);
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return single_result(rslt(bcx, llval));
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}
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var(disr_val, repr) => {
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return adt::trans_case(bcx, repr, disr_val);
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}
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range(l1, l2) => {
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let (l1, _) = consts::const_expr(ccx, l1);
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let (l2, _) = consts::const_expr(ccx, l2);
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return range_result(rslt(bcx, l1), rslt(bcx, l2));
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}
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vec_len(n, vec_len_eq, _) => {
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return single_result(rslt(bcx, C_int(ccx, n as int)));
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}
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vec_len(n, vec_len_ge(_), _) => {
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return lower_bound(rslt(bcx, C_int(ccx, n as int)));
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}
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}
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}
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fn variant_opt(bcx: @mut Block, pat_id: ast::NodeId)
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-> Opt {
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let ccx = bcx.ccx();
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match ccx.tcx.def_map.get_copy(&pat_id) {
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ast::DefVariant(enum_id, var_id, _) => {
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let variants = ty::enum_variants(ccx.tcx, enum_id);
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for v in (*variants).iter() {
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if var_id == v.id {
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return var(v.disr_val,
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adt::represent_node(bcx, pat_id))
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}
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}
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unreachable!();
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}
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ast::DefFn(*) |
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ast::DefStruct(_) => {
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return lit(UnitLikeStructLit(pat_id));
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}
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_ => {
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ccx.sess.bug("non-variant or struct in variant_opt()");
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}
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}
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}
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#[deriving(Clone)]
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enum TransBindingMode {
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TrByValue(/*llbinding:*/ ValueRef),
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TrByRef,
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}
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/**
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* Information about a pattern binding:
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* - `llmatch` is a pointer to a stack slot. The stack slot contains a
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* pointer into the value being matched. Hence, llmatch has type `T**`
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* where `T` is the value being matched.
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* - `trmode` is the trans binding mode
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* - `id` is the node id of the binding
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* - `ty` is the Rust type of the binding */
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#[deriving(Clone)]
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struct BindingInfo {
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llmatch: ValueRef,
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trmode: TransBindingMode,
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id: ast::NodeId,
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span: Span,
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ty: ty::t,
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}
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type BindingsMap = HashMap<Ident, BindingInfo>;
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#[deriving(Clone)]
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struct ArmData<'self> {
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bodycx: @mut Block,
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arm: &'self ast::Arm,
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bindings_map: @BindingsMap
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}
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/**
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* Info about Match.
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* If all `pats` are matched then arm `data` will be executed.
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* As we proceed `bound_ptrs` are filled with pointers to values to be bound,
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* these pointers are stored in llmatch variables just before executing `data` arm.
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*/
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#[deriving(Clone)]
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struct Match<'self> {
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pats: ~[@ast::Pat],
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data: ArmData<'self>,
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bound_ptrs: ~[(Ident, ValueRef)]
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}
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impl<'self> Repr for Match<'self> {
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fn repr(&self, tcx: ty::ctxt) -> ~str {
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if tcx.sess.verbose() {
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// for many programs, this just take too long to serialize
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self.pats.repr(tcx)
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} else {
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format!("{} pats", self.pats.len())
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}
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}
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}
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fn has_nested_bindings(m: &[Match], col: uint) -> bool {
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for br in m.iter() {
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match br.pats[col].node {
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ast::PatIdent(_, _, Some(_)) => return true,
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_ => ()
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}
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}
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return false;
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}
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fn expand_nested_bindings<'r>(bcx: @mut Block,
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m: &[Match<'r>],
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col: uint,
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val: ValueRef)
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-> ~[Match<'r>] {
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debug!("expand_nested_bindings(bcx={}, m={}, col={}, val={})",
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bcx.to_str(),
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m.repr(bcx.tcx()),
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col,
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bcx.val_to_str(val));
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let _indenter = indenter();
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do m.map |br| {
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match br.pats[col].node {
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ast::PatIdent(_, ref path, Some(inner)) => {
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let pats = vec::append(
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br.pats.slice(0u, col).to_owned(),
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vec::append(~[inner],
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br.pats.slice(col + 1u,
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br.pats.len())));
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let mut res = Match {
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pats: pats,
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data: br.data.clone(),
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bound_ptrs: br.bound_ptrs.clone()
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};
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res.bound_ptrs.push((path_to_ident(path), val));
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res
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}
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_ => (*br).clone(),
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}
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}
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}
|
|
|
|
fn assert_is_binding_or_wild(bcx: @mut Block, p: @ast::Pat) {
|
|
if !pat_is_binding_or_wild(bcx.tcx().def_map, p) {
|
|
bcx.sess().span_bug(
|
|
p.span,
|
|
format!("Expected an identifier pattern but found p: {}",
|
|
p.repr(bcx.tcx())));
|
|
}
|
|
}
|
|
|
|
type enter_pat<'self> = &'self fn(@ast::Pat) -> Option<~[@ast::Pat]>;
|
|
|
|
fn enter_match<'r>(bcx: @mut Block,
|
|
dm: DefMap,
|
|
m: &[Match<'r>],
|
|
col: uint,
|
|
val: ValueRef,
|
|
e: enter_pat)
|
|
-> ~[Match<'r>] {
|
|
debug!("enter_match(bcx={}, m={}, col={}, val={})",
|
|
bcx.to_str(),
|
|
m.repr(bcx.tcx()),
|
|
col,
|
|
bcx.val_to_str(val));
|
|
let _indenter = indenter();
|
|
|
|
let mut result = ~[];
|
|
for br in m.iter() {
|
|
match e(br.pats[col]) {
|
|
Some(sub) => {
|
|
let pats =
|
|
vec::append(
|
|
vec::append(sub, br.pats.slice(0u, col)),
|
|
br.pats.slice(col + 1u, br.pats.len()));
|
|
|
|
let this = br.pats[col];
|
|
let mut bound_ptrs = br.bound_ptrs.clone();
|
|
match this.node {
|
|
ast::PatIdent(_, ref path, None) => {
|
|
if pat_is_binding(dm, this) {
|
|
bound_ptrs.push((path_to_ident(path), val));
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
|
|
result.push(Match {
|
|
pats: pats,
|
|
data: br.data.clone(),
|
|
bound_ptrs: bound_ptrs
|
|
});
|
|
}
|
|
None => ()
|
|
}
|
|
}
|
|
|
|
debug!("result={}", result.repr(bcx.tcx()));
|
|
|
|
return result;
|
|
}
|
|
|
|
fn enter_default<'r>(bcx: @mut Block,
|
|
dm: DefMap,
|
|
m: &[Match<'r>],
|
|
col: uint,
|
|
val: ValueRef,
|
|
chk: FailureHandler)
|
|
-> ~[Match<'r>] {
|
|
debug!("enter_default(bcx={}, m={}, col={}, val={})",
|
|
bcx.to_str(),
|
|
m.repr(bcx.tcx()),
|
|
col,
|
|
bcx.val_to_str(val));
|
|
let _indenter = indenter();
|
|
|
|
// Collect all of the matches that can match against anything.
|
|
let matches = do enter_match(bcx, dm, m, col, val) |p| {
|
|
match p.node {
|
|
ast::PatWild | ast::PatTup(_) => Some(~[]),
|
|
ast::PatIdent(_, _, None) if pat_is_binding(dm, p) => Some(~[]),
|
|
_ => None
|
|
}
|
|
};
|
|
|
|
// Ok, now, this is pretty subtle. A "default" match is a match
|
|
// that needs to be considered if none of the actual checks on the
|
|
// value being considered succeed. The subtlety lies in that sometimes
|
|
// identifier/wildcard matches are *not* default matches. Consider:
|
|
// "match x { _ if something => foo, true => bar, false => baz }".
|
|
// There is a wildcard match, but it is *not* a default case. The boolean
|
|
// case on the value being considered is exhaustive. If the case is
|
|
// exhaustive, then there are no defaults.
|
|
//
|
|
// We detect whether the case is exhaustive in the following
|
|
// somewhat kludgy way: if the last wildcard/binding match has a
|
|
// guard, then by non-redundancy, we know that there aren't any
|
|
// non guarded matches, and thus by exhaustiveness, we know that
|
|
// we don't need any default cases. If the check *isn't* nonexhaustive
|
|
// (because chk is Some), then we need the defaults anyways.
|
|
let is_exhaustive = match matches.last_opt() {
|
|
Some(m) if m.data.arm.guard.is_some() && chk.is_infallible() => true,
|
|
_ => false
|
|
};
|
|
|
|
if is_exhaustive { ~[] } else { matches }
|
|
}
|
|
|
|
// <pcwalton> nmatsakis: what does enter_opt do?
|
|
// <pcwalton> in trans/match
|
|
// <pcwalton> trans/match.rs is like stumbling around in a dark cave
|
|
// <nmatsakis> pcwalton: the enter family of functions adjust the set of
|
|
// patterns as needed
|
|
// <nmatsakis> yeah, at some point I kind of achieved some level of
|
|
// understanding
|
|
// <nmatsakis> anyhow, they adjust the patterns given that something of that
|
|
// kind has been found
|
|
// <nmatsakis> pcwalton: ok, right, so enter_XXX() adjusts the patterns, as I
|
|
// said
|
|
// <nmatsakis> enter_match() kind of embodies the generic code
|
|
// <nmatsakis> it is provided with a function that tests each pattern to see
|
|
// if it might possibly apply and so forth
|
|
// <nmatsakis> so, if you have a pattern like {a: _, b: _, _} and one like _
|
|
// <nmatsakis> then _ would be expanded to (_, _)
|
|
// <nmatsakis> one spot for each of the sub-patterns
|
|
// <nmatsakis> enter_opt() is one of the more complex; it covers the fallible
|
|
// cases
|
|
// <nmatsakis> enter_rec_or_struct() or enter_tuple() are simpler, since they
|
|
// are infallible patterns
|
|
// <nmatsakis> so all patterns must either be records (resp. tuples) or
|
|
// wildcards
|
|
|
|
fn enter_opt<'r>(bcx: @mut Block,
|
|
m: &[Match<'r>],
|
|
opt: &Opt,
|
|
col: uint,
|
|
variant_size: uint,
|
|
val: ValueRef)
|
|
-> ~[Match<'r>] {
|
|
debug!("enter_opt(bcx={}, m={}, opt={:?}, col={}, val={})",
|
|
bcx.to_str(),
|
|
m.repr(bcx.tcx()),
|
|
*opt,
|
|
col,
|
|
bcx.val_to_str(val));
|
|
let _indenter = indenter();
|
|
|
|
let tcx = bcx.tcx();
|
|
let dummy = @ast::Pat {id: 0, node: ast::PatWild, span: dummy_sp()};
|
|
let mut i = 0;
|
|
do enter_match(bcx, tcx.def_map, m, col, val) |p| {
|
|
let answer = match p.node {
|
|
ast::PatEnum(*) |
|
|
ast::PatIdent(_, _, None) if pat_is_const(tcx.def_map, p) => {
|
|
let const_def = tcx.def_map.get_copy(&p.id);
|
|
let const_def_id = ast_util::def_id_of_def(const_def);
|
|
if opt_eq(tcx, &lit(ConstLit(const_def_id)), opt) {
|
|
Some(~[])
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
ast::PatEnum(_, ref subpats) => {
|
|
if opt_eq(tcx, &variant_opt(bcx, p.id), opt) {
|
|
// XXX: Must we clone?
|
|
match *subpats {
|
|
None => Some(vec::from_elem(variant_size, dummy)),
|
|
_ => (*subpats).clone(),
|
|
}
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
ast::PatIdent(_, _, None)
|
|
if pat_is_variant_or_struct(tcx.def_map, p) => {
|
|
if opt_eq(tcx, &variant_opt(bcx, p.id), opt) {
|
|
Some(~[])
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
ast::PatLit(l) => {
|
|
if opt_eq(tcx, &lit(ExprLit(l)), opt) {Some(~[])} else {None}
|
|
}
|
|
ast::PatRange(l1, l2) => {
|
|
if opt_eq(tcx, &range(l1, l2), opt) {Some(~[])} else {None}
|
|
}
|
|
ast::PatStruct(_, ref field_pats, _) => {
|
|
if opt_eq(tcx, &variant_opt(bcx, p.id), opt) {
|
|
// Look up the struct variant ID.
|
|
let struct_id;
|
|
match tcx.def_map.get_copy(&p.id) {
|
|
ast::DefVariant(_, found_struct_id, _) => {
|
|
struct_id = found_struct_id;
|
|
}
|
|
_ => {
|
|
tcx.sess.span_bug(p.span, "expected enum variant def");
|
|
}
|
|
}
|
|
|
|
// Reorder the patterns into the same order they were
|
|
// specified in the struct definition. Also fill in
|
|
// unspecified fields with dummy.
|
|
let mut reordered_patterns = ~[];
|
|
let r = ty::lookup_struct_fields(tcx, struct_id);
|
|
for field in r.iter() {
|
|
match field_pats.iter().find(|p| p.ident.name
|
|
== field.name) {
|
|
None => reordered_patterns.push(dummy),
|
|
Some(fp) => reordered_patterns.push(fp.pat)
|
|
}
|
|
}
|
|
Some(reordered_patterns)
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
ast::PatVec(ref before, slice, ref after) => {
|
|
let (lo, hi) = match *opt {
|
|
vec_len(_, _, (lo, hi)) => (lo, hi),
|
|
_ => tcx.sess.span_bug(p.span,
|
|
"vec pattern but not vec opt")
|
|
};
|
|
|
|
match slice {
|
|
Some(slice) if i >= lo && i <= hi => {
|
|
let n = before.len() + after.len();
|
|
let this_opt = vec_len(n, vec_len_ge(before.len()),
|
|
(lo, hi));
|
|
if opt_eq(tcx, &this_opt, opt) {
|
|
Some(vec::append_one((*before).clone(), slice) +
|
|
*after)
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
None if i >= lo && i <= hi => {
|
|
let n = before.len();
|
|
if opt_eq(tcx, &vec_len(n, vec_len_eq, (lo,hi)), opt) {
|
|
Some((*before).clone())
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
_ => None
|
|
}
|
|
}
|
|
_ => {
|
|
assert_is_binding_or_wild(bcx, p);
|
|
// In most cases, a binding/wildcard match be
|
|
// considered to match against any Opt. However, when
|
|
// doing vector pattern matching, submatches are
|
|
// considered even if the eventual match might be from
|
|
// a different submatch. Thus, when a submatch fails
|
|
// when doing a vector match, we proceed to the next
|
|
// submatch. Thus, including a default match would
|
|
// cause the default match to fire spuriously.
|
|
match *opt {
|
|
vec_len(*) => None,
|
|
_ => Some(vec::from_elem(variant_size, dummy))
|
|
}
|
|
}
|
|
};
|
|
i += 1;
|
|
answer
|
|
}
|
|
}
|
|
|
|
fn enter_rec_or_struct<'r>(bcx: @mut Block,
|
|
dm: DefMap,
|
|
m: &[Match<'r>],
|
|
col: uint,
|
|
fields: &[ast::Ident],
|
|
val: ValueRef)
|
|
-> ~[Match<'r>] {
|
|
debug!("enter_rec_or_struct(bcx={}, m={}, col={}, val={})",
|
|
bcx.to_str(),
|
|
m.repr(bcx.tcx()),
|
|
col,
|
|
bcx.val_to_str(val));
|
|
let _indenter = indenter();
|
|
|
|
let dummy = @ast::Pat {id: 0, node: ast::PatWild, span: dummy_sp()};
|
|
do enter_match(bcx, dm, m, col, val) |p| {
|
|
match p.node {
|
|
ast::PatStruct(_, ref fpats, _) => {
|
|
let mut pats = ~[];
|
|
for fname in fields.iter() {
|
|
match fpats.iter().find(|p| p.ident.name == fname.name) {
|
|
None => pats.push(dummy),
|
|
Some(pat) => pats.push(pat.pat)
|
|
}
|
|
}
|
|
Some(pats)
|
|
}
|
|
_ => {
|
|
assert_is_binding_or_wild(bcx, p);
|
|
Some(vec::from_elem(fields.len(), dummy))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn enter_tup<'r>(bcx: @mut Block,
|
|
dm: DefMap,
|
|
m: &[Match<'r>],
|
|
col: uint,
|
|
val: ValueRef,
|
|
n_elts: uint)
|
|
-> ~[Match<'r>] {
|
|
debug!("enter_tup(bcx={}, m={}, col={}, val={})",
|
|
bcx.to_str(),
|
|
m.repr(bcx.tcx()),
|
|
col,
|
|
bcx.val_to_str(val));
|
|
let _indenter = indenter();
|
|
|
|
let dummy = @ast::Pat {id: 0, node: ast::PatWild, span: dummy_sp()};
|
|
do enter_match(bcx, dm, m, col, val) |p| {
|
|
match p.node {
|
|
ast::PatTup(ref elts) => Some((*elts).clone()),
|
|
_ => {
|
|
assert_is_binding_or_wild(bcx, p);
|
|
Some(vec::from_elem(n_elts, dummy))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn enter_tuple_struct<'r>(bcx: @mut Block,
|
|
dm: DefMap,
|
|
m: &[Match<'r>],
|
|
col: uint,
|
|
val: ValueRef,
|
|
n_elts: uint)
|
|
-> ~[Match<'r>] {
|
|
debug!("enter_tuple_struct(bcx={}, m={}, col={}, val={})",
|
|
bcx.to_str(),
|
|
m.repr(bcx.tcx()),
|
|
col,
|
|
bcx.val_to_str(val));
|
|
let _indenter = indenter();
|
|
|
|
let dummy = @ast::Pat {id: 0, node: ast::PatWild, span: dummy_sp()};
|
|
do enter_match(bcx, dm, m, col, val) |p| {
|
|
match p.node {
|
|
ast::PatEnum(_, Some(ref elts)) => Some((*elts).clone()),
|
|
_ => {
|
|
assert_is_binding_or_wild(bcx, p);
|
|
Some(vec::from_elem(n_elts, dummy))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn enter_box<'r>(bcx: @mut Block,
|
|
dm: DefMap,
|
|
m: &[Match<'r>],
|
|
col: uint,
|
|
val: ValueRef)
|
|
-> ~[Match<'r>] {
|
|
debug!("enter_box(bcx={}, m={}, col={}, val={})",
|
|
bcx.to_str(),
|
|
m.repr(bcx.tcx()),
|
|
col,
|
|
bcx.val_to_str(val));
|
|
let _indenter = indenter();
|
|
|
|
let dummy = @ast::Pat {id: 0, node: ast::PatWild, span: dummy_sp()};
|
|
do enter_match(bcx, dm, m, col, val) |p| {
|
|
match p.node {
|
|
ast::PatBox(sub) => {
|
|
Some(~[sub])
|
|
}
|
|
_ => {
|
|
assert_is_binding_or_wild(bcx, p);
|
|
Some(~[dummy])
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn enter_uniq<'r>(bcx: @mut Block,
|
|
dm: DefMap,
|
|
m: &[Match<'r>],
|
|
col: uint,
|
|
val: ValueRef)
|
|
-> ~[Match<'r>] {
|
|
debug!("enter_uniq(bcx={}, m={}, col={}, val={})",
|
|
bcx.to_str(),
|
|
m.repr(bcx.tcx()),
|
|
col,
|
|
bcx.val_to_str(val));
|
|
let _indenter = indenter();
|
|
|
|
let dummy = @ast::Pat {id: 0, node: ast::PatWild, span: dummy_sp()};
|
|
do enter_match(bcx, dm, m, col, val) |p| {
|
|
match p.node {
|
|
ast::PatUniq(sub) => {
|
|
Some(~[sub])
|
|
}
|
|
_ => {
|
|
assert_is_binding_or_wild(bcx, p);
|
|
Some(~[dummy])
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn enter_region<'r>(bcx: @mut Block,
|
|
dm: DefMap,
|
|
m: &[Match<'r>],
|
|
col: uint,
|
|
val: ValueRef)
|
|
-> ~[Match<'r>] {
|
|
debug!("enter_region(bcx={}, m={}, col={}, val={})",
|
|
bcx.to_str(),
|
|
m.repr(bcx.tcx()),
|
|
col,
|
|
bcx.val_to_str(val));
|
|
let _indenter = indenter();
|
|
|
|
let dummy = @ast::Pat { id: 0, node: ast::PatWild, span: dummy_sp() };
|
|
do enter_match(bcx, dm, m, col, val) |p| {
|
|
match p.node {
|
|
ast::PatRegion(sub) => {
|
|
Some(~[sub])
|
|
}
|
|
_ => {
|
|
assert_is_binding_or_wild(bcx, p);
|
|
Some(~[dummy])
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Returns the options in one column of matches. An option is something that
|
|
// needs to be conditionally matched at runtime; for example, the discriminant
|
|
// on a set of enum variants or a literal.
|
|
fn get_options(bcx: @mut Block, m: &[Match], col: uint) -> ~[Opt] {
|
|
let ccx = bcx.ccx();
|
|
fn add_to_set(tcx: ty::ctxt, set: &mut ~[Opt], val: Opt) {
|
|
if set.iter().any(|l| opt_eq(tcx, l, &val)) {return;}
|
|
set.push(val);
|
|
}
|
|
// Vector comparisions are special in that since the actual
|
|
// conditions over-match, we need to be careful about them. This
|
|
// means that in order to properly handle things in order, we need
|
|
// to not always merge conditions.
|
|
fn add_veclen_to_set(set: &mut ~[Opt], i: uint,
|
|
len: uint, vlo: VecLenOpt) {
|
|
match set.last_opt() {
|
|
// If the last condition in the list matches the one we want
|
|
// to add, then extend its range. Otherwise, make a new
|
|
// vec_len with a range just covering the new entry.
|
|
Some(&vec_len(len2, vlo2, (start, end)))
|
|
if len == len2 && vlo == vlo2 =>
|
|
set[set.len() - 1] = vec_len(len, vlo, (start, end+1)),
|
|
_ => set.push(vec_len(len, vlo, (i, i)))
|
|
}
|
|
}
|
|
|
|
let mut found = ~[];
|
|
for (i, br) in m.iter().enumerate() {
|
|
let cur = br.pats[col];
|
|
match cur.node {
|
|
ast::PatLit(l) => {
|
|
add_to_set(ccx.tcx, &mut found, lit(ExprLit(l)));
|
|
}
|
|
ast::PatIdent(*) => {
|
|
// This is one of: an enum variant, a unit-like struct, or a
|
|
// variable binding.
|
|
match ccx.tcx.def_map.find(&cur.id) {
|
|
Some(&ast::DefVariant(*)) => {
|
|
add_to_set(ccx.tcx, &mut found,
|
|
variant_opt(bcx, cur.id));
|
|
}
|
|
Some(&ast::DefStruct(*)) => {
|
|
add_to_set(ccx.tcx, &mut found,
|
|
lit(UnitLikeStructLit(cur.id)));
|
|
}
|
|
Some(&ast::DefStatic(const_did, false)) => {
|
|
add_to_set(ccx.tcx, &mut found,
|
|
lit(ConstLit(const_did)));
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
ast::PatEnum(*) | ast::PatStruct(*) => {
|
|
// This could be one of: a tuple-like enum variant, a
|
|
// struct-like enum variant, or a struct.
|
|
match ccx.tcx.def_map.find(&cur.id) {
|
|
Some(&ast::DefFn(*)) |
|
|
Some(&ast::DefVariant(*)) => {
|
|
add_to_set(ccx.tcx, &mut found,
|
|
variant_opt(bcx, cur.id));
|
|
}
|
|
Some(&ast::DefStatic(const_did, false)) => {
|
|
add_to_set(ccx.tcx, &mut found,
|
|
lit(ConstLit(const_did)));
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
ast::PatRange(l1, l2) => {
|
|
add_to_set(ccx.tcx, &mut found, range(l1, l2));
|
|
}
|
|
ast::PatVec(ref before, slice, ref after) => {
|
|
let (len, vec_opt) = match slice {
|
|
None => (before.len(), vec_len_eq),
|
|
Some(_) => (before.len() + after.len(),
|
|
vec_len_ge(before.len()))
|
|
};
|
|
add_veclen_to_set(&mut found, i, len, vec_opt);
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
return found;
|
|
}
|
|
|
|
struct ExtractedBlock {
|
|
vals: ~[ValueRef],
|
|
bcx: @mut Block
|
|
}
|
|
|
|
fn extract_variant_args(bcx: @mut Block,
|
|
repr: &adt::Repr,
|
|
disr_val: ty::Disr,
|
|
val: ValueRef)
|
|
-> ExtractedBlock {
|
|
let _icx = push_ctxt("match::extract_variant_args");
|
|
let args = do vec::from_fn(adt::num_args(repr, disr_val)) |i| {
|
|
adt::trans_field_ptr(bcx, repr, val, disr_val, i)
|
|
};
|
|
|
|
ExtractedBlock { vals: args, bcx: bcx }
|
|
}
|
|
|
|
fn match_datum(bcx: @mut Block, val: ValueRef, pat_id: ast::NodeId) -> Datum {
|
|
//! Helper for converting from the ValueRef that we pass around in
|
|
//! the match code, which is always by ref, into a Datum. Eventually
|
|
//! we should just pass around a Datum and be done with it.
|
|
|
|
let ty = node_id_type(bcx, pat_id);
|
|
Datum {val: val, ty: ty, mode: datum::ByRef(RevokeClean)}
|
|
}
|
|
|
|
|
|
fn extract_vec_elems(bcx: @mut Block,
|
|
pat_span: Span,
|
|
pat_id: ast::NodeId,
|
|
elem_count: uint,
|
|
slice: Option<uint>,
|
|
val: ValueRef,
|
|
count: ValueRef)
|
|
-> ExtractedBlock {
|
|
let _icx = push_ctxt("match::extract_vec_elems");
|
|
let vec_datum = match_datum(bcx, val, pat_id);
|
|
let (bcx, base, len) = vec_datum.get_vec_base_and_len(bcx, pat_span, pat_id, 0);
|
|
let vt = tvec::vec_types(bcx, node_id_type(bcx, pat_id));
|
|
|
|
let mut elems = do vec::from_fn(elem_count) |i| {
|
|
match slice {
|
|
None => GEPi(bcx, base, [i]),
|
|
Some(n) if i < n => GEPi(bcx, base, [i]),
|
|
Some(n) if i > n => {
|
|
InBoundsGEP(bcx, base, [
|
|
Sub(bcx, count,
|
|
C_int(bcx.ccx(), (elem_count - i) as int))])
|
|
}
|
|
_ => unsafe { llvm::LLVMGetUndef(vt.llunit_ty.to_ref()) }
|
|
}
|
|
};
|
|
if slice.is_some() {
|
|
let n = slice.unwrap();
|
|
let slice_byte_offset = Mul(bcx, vt.llunit_size, C_uint(bcx.ccx(), n));
|
|
let slice_begin = tvec::pointer_add_byte(bcx, base, slice_byte_offset);
|
|
let slice_len_offset = C_uint(bcx.ccx(), elem_count - 1u);
|
|
let slice_len = Sub(bcx, len, slice_len_offset);
|
|
let slice_ty = ty::mk_evec(bcx.tcx(),
|
|
ty::mt {ty: vt.unit_ty, mutbl: ast::MutImmutable},
|
|
ty::vstore_slice(ty::re_static)
|
|
);
|
|
let scratch = scratch_datum(bcx, slice_ty, "", false);
|
|
Store(bcx, slice_begin,
|
|
GEPi(bcx, scratch.val, [0u, abi::slice_elt_base])
|
|
);
|
|
Store(bcx, slice_len, GEPi(bcx, scratch.val, [0u, abi::slice_elt_len]));
|
|
elems[n] = scratch.val;
|
|
scratch.add_clean(bcx);
|
|
}
|
|
|
|
ExtractedBlock { vals: elems, bcx: bcx }
|
|
}
|
|
|
|
/// Checks every pattern in `m` at `col` column.
|
|
/// If there are a struct pattern among them function
|
|
/// returns list of all fields that are matched in these patterns.
|
|
/// Function returns None if there is no struct pattern.
|
|
/// Function doesn't collect fields from struct-like enum variants.
|
|
/// Function can return empty list if there is only wildcard struct pattern.
|
|
fn collect_record_or_struct_fields(bcx: @mut Block,
|
|
m: &[Match],
|
|
col: uint)
|
|
-> Option<~[ast::Ident]> {
|
|
let mut fields: ~[ast::Ident] = ~[];
|
|
let mut found = false;
|
|
for br in m.iter() {
|
|
match br.pats[col].node {
|
|
ast::PatStruct(_, ref fs, _) => {
|
|
match ty::get(node_id_type(bcx, br.pats[col].id)).sty {
|
|
ty::ty_struct(*) => {
|
|
extend(&mut fields, *fs);
|
|
found = true;
|
|
}
|
|
_ => ()
|
|
}
|
|
}
|
|
_ => ()
|
|
}
|
|
}
|
|
if found {
|
|
return Some(fields);
|
|
} else {
|
|
return None;
|
|
}
|
|
|
|
fn extend(idents: &mut ~[ast::Ident], field_pats: &[ast::FieldPat]) {
|
|
for field_pat in field_pats.iter() {
|
|
let field_ident = field_pat.ident;
|
|
if !idents.iter().any(|x| x.name == field_ident.name) {
|
|
idents.push(field_ident);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn pats_require_rooting(bcx: @mut Block,
|
|
m: &[Match],
|
|
col: uint)
|
|
-> bool {
|
|
do m.iter().any |br| {
|
|
let pat_id = br.pats[col].id;
|
|
let key = root_map_key {id: pat_id, derefs: 0u };
|
|
bcx.ccx().maps.root_map.contains_key(&key)
|
|
}
|
|
}
|
|
|
|
fn root_pats_as_necessary(mut bcx: @mut Block,
|
|
m: &[Match],
|
|
col: uint,
|
|
val: ValueRef)
|
|
-> @mut Block {
|
|
for br in m.iter() {
|
|
let pat_id = br.pats[col].id;
|
|
if pat_id != 0 {
|
|
let datum = Datum {val: val, ty: node_id_type(bcx, pat_id),
|
|
mode: ByRef(ZeroMem)};
|
|
bcx = datum.root_and_write_guard(bcx, br.pats[col].span, pat_id, 0);
|
|
}
|
|
}
|
|
return bcx;
|
|
}
|
|
|
|
// Macro for deciding whether any of the remaining matches fit a given kind of
|
|
// pattern. Note that, because the macro is well-typed, either ALL of the
|
|
// matches should fit that sort of pattern or NONE (however, some of the
|
|
// matches may be wildcards like _ or identifiers).
|
|
macro_rules! any_pat (
|
|
($m:expr, $pattern:pat) => (
|
|
do ($m).iter().any |br| {
|
|
match br.pats[col].node {
|
|
$pattern => true,
|
|
_ => false
|
|
}
|
|
}
|
|
)
|
|
)
|
|
|
|
fn any_box_pat(m: &[Match], col: uint) -> bool {
|
|
any_pat!(m, ast::PatBox(_))
|
|
}
|
|
|
|
fn any_uniq_pat(m: &[Match], col: uint) -> bool {
|
|
any_pat!(m, ast::PatUniq(_))
|
|
}
|
|
|
|
fn any_region_pat(m: &[Match], col: uint) -> bool {
|
|
any_pat!(m, ast::PatRegion(_))
|
|
}
|
|
|
|
fn any_tup_pat(m: &[Match], col: uint) -> bool {
|
|
any_pat!(m, ast::PatTup(_))
|
|
}
|
|
|
|
fn any_tuple_struct_pat(bcx: @mut Block, m: &[Match], col: uint) -> bool {
|
|
do m.iter().any |br| {
|
|
let pat = br.pats[col];
|
|
match pat.node {
|
|
ast::PatEnum(_, Some(_)) => {
|
|
match bcx.tcx().def_map.find(&pat.id) {
|
|
Some(&ast::DefFn(*)) |
|
|
Some(&ast::DefStruct(*)) => true,
|
|
_ => false
|
|
}
|
|
}
|
|
_ => false
|
|
}
|
|
}
|
|
}
|
|
|
|
trait CustomFailureHandler {
|
|
fn handle_fail(&self) -> BasicBlockRef;
|
|
}
|
|
|
|
struct DynamicFailureHandler {
|
|
bcx: @mut Block,
|
|
sp: Span,
|
|
msg: @str,
|
|
finished: @mut Option<BasicBlockRef>,
|
|
}
|
|
|
|
impl CustomFailureHandler for DynamicFailureHandler {
|
|
fn handle_fail(&self) -> BasicBlockRef {
|
|
match *self.finished {
|
|
Some(bb) => return bb,
|
|
_ => (),
|
|
}
|
|
|
|
let fail_cx = sub_block(self.bcx, "case_fallthrough");
|
|
controlflow::trans_fail(fail_cx, Some(self.sp), self.msg);
|
|
*self.finished = Some(fail_cx.llbb);
|
|
fail_cx.llbb
|
|
}
|
|
}
|
|
|
|
/// What to do when the pattern match fails.
|
|
enum FailureHandler {
|
|
Infallible,
|
|
JumpToBasicBlock(BasicBlockRef),
|
|
CustomFailureHandlerClass(@CustomFailureHandler),
|
|
}
|
|
|
|
impl FailureHandler {
|
|
fn is_infallible(&self) -> bool {
|
|
match *self {
|
|
Infallible => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
fn is_fallible(&self) -> bool {
|
|
!self.is_infallible()
|
|
}
|
|
|
|
fn handle_fail(&self) -> BasicBlockRef {
|
|
match *self {
|
|
Infallible => {
|
|
fail!("attempted to fail in infallible failure handler!")
|
|
}
|
|
JumpToBasicBlock(basic_block) => basic_block,
|
|
CustomFailureHandlerClass(custom_failure_handler) => {
|
|
custom_failure_handler.handle_fail()
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn pick_col(m: &[Match]) -> uint {
|
|
fn score(p: &ast::Pat) -> uint {
|
|
match p.node {
|
|
ast::PatLit(_) | ast::PatEnum(_, _) | ast::PatRange(_, _) => 1u,
|
|
ast::PatIdent(_, _, Some(p)) => score(p),
|
|
_ => 0u
|
|
}
|
|
}
|
|
let mut scores = vec::from_elem(m[0].pats.len(), 0u);
|
|
for br in m.iter() {
|
|
for (i, p) in br.pats.iter().enumerate() {
|
|
scores[i] += score(*p);
|
|
}
|
|
}
|
|
let mut max_score = 0u;
|
|
let mut best_col = 0u;
|
|
for (i, score) in scores.iter().enumerate() {
|
|
let score = *score;
|
|
|
|
// Irrefutable columns always go first, they'd only be duplicated in
|
|
// the branches.
|
|
if score == 0u { return i; }
|
|
// If no irrefutable ones are found, we pick the one with the biggest
|
|
// branching factor.
|
|
if score > max_score { max_score = score; best_col = i; }
|
|
}
|
|
return best_col;
|
|
}
|
|
|
|
#[deriving(Eq)]
|
|
pub enum branch_kind { no_branch, single, switch, compare, compare_vec_len, }
|
|
|
|
// Compiles a comparison between two things.
|
|
//
|
|
// NB: This must produce an i1, not a Rust bool (i8).
|
|
fn compare_values(cx: @mut Block,
|
|
lhs: ValueRef,
|
|
rhs: ValueRef,
|
|
rhs_t: ty::t)
|
|
-> Result {
|
|
let _icx = push_ctxt("compare_values");
|
|
if ty::type_is_scalar(rhs_t) {
|
|
let rs = compare_scalar_types(cx, lhs, rhs, rhs_t, ast::BiEq);
|
|
return rslt(rs.bcx, rs.val);
|
|
}
|
|
|
|
match ty::get(rhs_t).sty {
|
|
ty::ty_estr(ty::vstore_uniq) => {
|
|
let scratch_lhs = alloca(cx, val_ty(lhs), "__lhs");
|
|
Store(cx, lhs, scratch_lhs);
|
|
let scratch_rhs = alloca(cx, val_ty(rhs), "__rhs");
|
|
Store(cx, rhs, scratch_rhs);
|
|
let did = langcall(cx, None,
|
|
format!("comparison of `{}`", cx.ty_to_str(rhs_t)),
|
|
UniqStrEqFnLangItem);
|
|
let result = callee::trans_lang_call(cx, did, [scratch_lhs, scratch_rhs], None);
|
|
Result {
|
|
bcx: result.bcx,
|
|
val: bool_to_i1(result.bcx, result.val)
|
|
}
|
|
}
|
|
ty::ty_estr(_) => {
|
|
let did = langcall(cx, None,
|
|
format!("comparison of `{}`", cx.ty_to_str(rhs_t)),
|
|
StrEqFnLangItem);
|
|
let result = callee::trans_lang_call(cx, did, [lhs, rhs], None);
|
|
Result {
|
|
bcx: result.bcx,
|
|
val: bool_to_i1(result.bcx, result.val)
|
|
}
|
|
}
|
|
_ => {
|
|
cx.tcx().sess.bug("only scalars and strings supported in \
|
|
compare_values");
|
|
}
|
|
}
|
|
}
|
|
|
|
fn store_non_ref_bindings(bcx: @mut Block,
|
|
bindings_map: &BindingsMap,
|
|
mut opt_temp_cleanups: Option<&mut ~[ValueRef]>)
|
|
-> @mut Block
|
|
{
|
|
/*!
|
|
*
|
|
* For each copy/move binding, copy the value from the value
|
|
* being matched into its final home. This code executes once
|
|
* one of the patterns for a given arm has completely matched.
|
|
* It adds temporary cleanups to the `temp_cleanups` array,
|
|
* if one is provided.
|
|
*/
|
|
|
|
let mut bcx = bcx;
|
|
for (_, &binding_info) in bindings_map.iter() {
|
|
match binding_info.trmode {
|
|
TrByValue(lldest) => {
|
|
let llval = Load(bcx, binding_info.llmatch); // get a T*
|
|
let datum = Datum {val: llval, ty: binding_info.ty,
|
|
mode: ByRef(ZeroMem)};
|
|
bcx = datum.store_to(bcx, INIT, lldest);
|
|
do opt_temp_cleanups.mutate |temp_cleanups| {
|
|
add_clean_temp_mem(bcx, lldest, binding_info.ty);
|
|
temp_cleanups.push(lldest);
|
|
temp_cleanups
|
|
};
|
|
}
|
|
TrByRef => {}
|
|
}
|
|
}
|
|
return bcx;
|
|
}
|
|
|
|
fn insert_lllocals(bcx: @mut Block,
|
|
bindings_map: &BindingsMap,
|
|
add_cleans: bool) -> @mut Block {
|
|
/*!
|
|
* For each binding in `data.bindings_map`, adds an appropriate entry into
|
|
* the `fcx.lllocals` map. If add_cleans is true, then adds cleanups for
|
|
* the bindings.
|
|
*/
|
|
|
|
let llmap = bcx.fcx.lllocals;
|
|
|
|
for (&ident, &binding_info) in bindings_map.iter() {
|
|
let llval = match binding_info.trmode {
|
|
// By value bindings: use the stack slot that we
|
|
// copied/moved the value into
|
|
TrByValue(lldest) => {
|
|
if add_cleans {
|
|
add_clean(bcx, lldest, binding_info.ty);
|
|
}
|
|
|
|
lldest
|
|
}
|
|
|
|
// By ref binding: use the ptr into the matched value
|
|
TrByRef => {
|
|
binding_info.llmatch
|
|
}
|
|
};
|
|
|
|
debug!("binding {:?} to {}", binding_info.id, bcx.val_to_str(llval));
|
|
llmap.insert(binding_info.id, llval);
|
|
|
|
if bcx.sess().opts.extra_debuginfo {
|
|
debuginfo::create_match_binding_metadata(bcx,
|
|
ident,
|
|
binding_info.id,
|
|
binding_info.ty,
|
|
binding_info.span);
|
|
}
|
|
}
|
|
return bcx;
|
|
}
|
|
|
|
fn compile_guard(bcx: @mut Block,
|
|
guard_expr: &ast::Expr,
|
|
data: &ArmData,
|
|
m: &[Match],
|
|
vals: &[ValueRef],
|
|
chk: FailureHandler)
|
|
-> @mut Block {
|
|
debug!("compile_guard(bcx={}, guard_expr={}, m={}, vals={})",
|
|
bcx.to_str(),
|
|
bcx.expr_to_str(guard_expr),
|
|
m.repr(bcx.tcx()),
|
|
vec_map_to_str(vals, |v| bcx.val_to_str(*v)));
|
|
let _indenter = indenter();
|
|
|
|
let mut bcx = bcx;
|
|
let mut temp_cleanups = ~[];
|
|
bcx = store_non_ref_bindings(bcx,
|
|
data.bindings_map,
|
|
Some(&mut temp_cleanups));
|
|
bcx = insert_lllocals(bcx, data.bindings_map, false);
|
|
|
|
let val = unpack_result!(bcx, {
|
|
do with_scope_result(bcx, guard_expr.info(),
|
|
"guard") |bcx| {
|
|
expr::trans_to_datum(bcx, guard_expr).to_result()
|
|
}
|
|
});
|
|
let val = bool_to_i1(bcx, val);
|
|
|
|
// Revoke the temp cleanups now that the guard successfully executed.
|
|
for llval in temp_cleanups.iter() {
|
|
revoke_clean(bcx, *llval);
|
|
}
|
|
|
|
return do with_cond(bcx, Not(bcx, val)) |bcx| {
|
|
// Guard does not match: free the values we copied,
|
|
// and remove all bindings from the lllocals table
|
|
let bcx = drop_bindings(bcx, data);
|
|
compile_submatch(bcx, m, vals, chk);
|
|
bcx
|
|
};
|
|
|
|
fn drop_bindings(bcx: @mut Block, data: &ArmData) -> @mut Block {
|
|
let mut bcx = bcx;
|
|
for (_, &binding_info) in data.bindings_map.iter() {
|
|
match binding_info.trmode {
|
|
TrByValue(llval) => {
|
|
bcx = glue::drop_ty(bcx, llval, binding_info.ty);
|
|
}
|
|
TrByRef => {}
|
|
}
|
|
bcx.fcx.lllocals.remove(&binding_info.id);
|
|
}
|
|
return bcx;
|
|
}
|
|
}
|
|
|
|
fn compile_submatch(bcx: @mut Block,
|
|
m: &[Match],
|
|
vals: &[ValueRef],
|
|
chk: FailureHandler) {
|
|
debug!("compile_submatch(bcx={}, m={}, vals={})",
|
|
bcx.to_str(),
|
|
m.repr(bcx.tcx()),
|
|
vec_map_to_str(vals, |v| bcx.val_to_str(*v)));
|
|
let _indenter = indenter();
|
|
|
|
/*
|
|
For an empty match, a fall-through case must exist
|
|
*/
|
|
assert!((m.len() > 0u || chk.is_fallible()));
|
|
let _icx = push_ctxt("match::compile_submatch");
|
|
let mut bcx = bcx;
|
|
if m.len() == 0u {
|
|
Br(bcx, chk.handle_fail());
|
|
return;
|
|
}
|
|
if m[0].pats.len() == 0u {
|
|
let data = &m[0].data;
|
|
for &(ref ident, ref value_ptr) in m[0].bound_ptrs.iter() {
|
|
let llmatch = data.bindings_map.get(ident).llmatch;
|
|
Store(bcx, *value_ptr, llmatch);
|
|
}
|
|
match data.arm.guard {
|
|
Some(guard_expr) => {
|
|
bcx = compile_guard(bcx,
|
|
guard_expr,
|
|
&m[0].data,
|
|
m.slice(1, m.len()),
|
|
vals,
|
|
chk);
|
|
}
|
|
_ => ()
|
|
}
|
|
Br(bcx, data.bodycx.llbb);
|
|
return;
|
|
}
|
|
|
|
let col = pick_col(m);
|
|
let val = vals[col];
|
|
|
|
if has_nested_bindings(m, col) {
|
|
let expanded = expand_nested_bindings(bcx, m, col, val);
|
|
compile_submatch_continue(bcx, expanded, vals, chk, col, val)
|
|
} else {
|
|
compile_submatch_continue(bcx, m, vals, chk, col, val)
|
|
}
|
|
}
|
|
|
|
fn compile_submatch_continue(mut bcx: @mut Block,
|
|
m: &[Match],
|
|
vals: &[ValueRef],
|
|
chk: FailureHandler,
|
|
col: uint,
|
|
val: ValueRef) {
|
|
let tcx = bcx.tcx();
|
|
let dm = tcx.def_map;
|
|
|
|
let vals_left = vec::append(vals.slice(0u, col).to_owned(),
|
|
vals.slice(col + 1u, vals.len()));
|
|
let ccx = bcx.fcx.ccx;
|
|
let mut pat_id = 0;
|
|
let mut pat_span = dummy_sp();
|
|
for br in m.iter() {
|
|
// Find a real id (we're adding placeholder wildcard patterns, but
|
|
// each column is guaranteed to have at least one real pattern)
|
|
if pat_id == 0 {
|
|
pat_id = br.pats[col].id;
|
|
pat_span = br.pats[col].span;
|
|
}
|
|
}
|
|
|
|
// If we are not matching against an `@T`, we should not be
|
|
// required to root any values.
|
|
assert!(any_box_pat(m, col) || !pats_require_rooting(bcx, m, col));
|
|
|
|
match collect_record_or_struct_fields(bcx, m, col) {
|
|
Some(ref rec_fields) => {
|
|
let pat_ty = node_id_type(bcx, pat_id);
|
|
let pat_repr = adt::represent_type(bcx.ccx(), pat_ty);
|
|
do expr::with_field_tys(tcx, pat_ty, None) |discr, field_tys| {
|
|
let rec_vals = rec_fields.map(|field_name| {
|
|
let ix = ty::field_idx_strict(tcx, field_name.name, field_tys);
|
|
adt::trans_field_ptr(bcx, pat_repr, val, discr, ix)
|
|
});
|
|
compile_submatch(
|
|
bcx,
|
|
enter_rec_or_struct(bcx, dm, m, col, *rec_fields, val),
|
|
vec::append(rec_vals, vals_left),
|
|
chk);
|
|
}
|
|
return;
|
|
}
|
|
None => {}
|
|
}
|
|
|
|
if any_tup_pat(m, col) {
|
|
let tup_ty = node_id_type(bcx, pat_id);
|
|
let tup_repr = adt::represent_type(bcx.ccx(), tup_ty);
|
|
let n_tup_elts = match ty::get(tup_ty).sty {
|
|
ty::ty_tup(ref elts) => elts.len(),
|
|
_ => ccx.sess.bug("non-tuple type in tuple pattern")
|
|
};
|
|
let tup_vals = do vec::from_fn(n_tup_elts) |i| {
|
|
adt::trans_field_ptr(bcx, tup_repr, val, 0, i)
|
|
};
|
|
compile_submatch(bcx, enter_tup(bcx, dm, m, col, val, n_tup_elts),
|
|
vec::append(tup_vals, vals_left), chk);
|
|
return;
|
|
}
|
|
|
|
if any_tuple_struct_pat(bcx, m, col) {
|
|
let struct_ty = node_id_type(bcx, pat_id);
|
|
let struct_element_count;
|
|
match ty::get(struct_ty).sty {
|
|
ty::ty_struct(struct_id, _) => {
|
|
struct_element_count =
|
|
ty::lookup_struct_fields(tcx, struct_id).len();
|
|
}
|
|
_ => {
|
|
ccx.sess.bug("non-struct type in tuple struct pattern");
|
|
}
|
|
}
|
|
|
|
let struct_repr = adt::represent_type(bcx.ccx(), struct_ty);
|
|
let llstructvals = do vec::from_fn(struct_element_count) |i| {
|
|
adt::trans_field_ptr(bcx, struct_repr, val, 0, i)
|
|
};
|
|
compile_submatch(bcx,
|
|
enter_tuple_struct(bcx, dm, m, col, val,
|
|
struct_element_count),
|
|
vec::append(llstructvals, vals_left),
|
|
chk);
|
|
return;
|
|
}
|
|
|
|
// Unbox in case of a box field
|
|
if any_box_pat(m, col) {
|
|
bcx = root_pats_as_necessary(bcx, m, col, val);
|
|
let llbox = Load(bcx, val);
|
|
let unboxed = GEPi(bcx, llbox, [0u, abi::box_field_body]);
|
|
compile_submatch(bcx, enter_box(bcx, dm, m, col, val),
|
|
vec::append(~[unboxed], vals_left), chk);
|
|
return;
|
|
}
|
|
|
|
if any_uniq_pat(m, col) {
|
|
let pat_ty = node_id_type(bcx, pat_id);
|
|
let llbox = Load(bcx, val);
|
|
let unboxed = match ty::get(pat_ty).sty {
|
|
ty::ty_uniq(*) if !ty::type_contents(bcx.tcx(), pat_ty).contains_managed() => llbox,
|
|
_ => GEPi(bcx, llbox, [0u, abi::box_field_body])
|
|
};
|
|
compile_submatch(bcx, enter_uniq(bcx, dm, m, col, val),
|
|
vec::append(~[unboxed], vals_left), chk);
|
|
return;
|
|
}
|
|
|
|
if any_region_pat(m, col) {
|
|
let loaded_val = Load(bcx, val);
|
|
compile_submatch(bcx, enter_region(bcx, dm, m, col, val),
|
|
vec::append(~[loaded_val], vals_left), chk);
|
|
return;
|
|
}
|
|
|
|
// Decide what kind of branch we need
|
|
let opts = get_options(bcx, m, col);
|
|
debug!("options={:?}", opts);
|
|
let mut kind = no_branch;
|
|
let mut test_val = val;
|
|
if opts.len() > 0u {
|
|
match opts[0] {
|
|
var(_, repr) => {
|
|
let (the_kind, val_opt) = adt::trans_switch(bcx, repr, val);
|
|
kind = the_kind;
|
|
for &tval in val_opt.iter() { test_val = tval; }
|
|
}
|
|
lit(_) => {
|
|
let pty = node_id_type(bcx, pat_id);
|
|
test_val = load_if_immediate(bcx, val, pty);
|
|
kind = if ty::type_is_integral(pty) { switch }
|
|
else { compare };
|
|
}
|
|
range(_, _) => {
|
|
test_val = Load(bcx, val);
|
|
kind = compare;
|
|
},
|
|
vec_len(*) => {
|
|
let vt = tvec::vec_types(bcx, node_id_type(bcx, pat_id));
|
|
let unboxed = load_if_immediate(bcx, val, vt.vec_ty);
|
|
let (_, len) = tvec::get_base_and_len(bcx, unboxed, vt.vec_ty);
|
|
test_val = len;
|
|
kind = compare_vec_len;
|
|
}
|
|
}
|
|
}
|
|
for o in opts.iter() {
|
|
match *o {
|
|
range(_, _) => { kind = compare; break }
|
|
_ => ()
|
|
}
|
|
}
|
|
let else_cx = match kind {
|
|
no_branch | single => bcx,
|
|
_ => sub_block(bcx, "match_else")
|
|
};
|
|
let sw = if kind == switch {
|
|
Switch(bcx, test_val, else_cx.llbb, opts.len())
|
|
} else {
|
|
C_int(ccx, 0) // Placeholder for when not using a switch
|
|
};
|
|
|
|
let defaults = enter_default(else_cx, dm, m, col, val, chk);
|
|
let exhaustive = chk.is_infallible() && defaults.len() == 0u;
|
|
let len = opts.len();
|
|
|
|
// Compile subtrees for each option
|
|
for (i, opt) in opts.iter().enumerate() {
|
|
// In some cases in vector pattern matching, we need to override
|
|
// the failure case so that instead of failing, it proceeds to
|
|
// try more matching. branch_chk, then, is the proper failure case
|
|
// for the current conditional branch.
|
|
let mut branch_chk = chk;
|
|
let mut opt_cx = else_cx;
|
|
if !exhaustive || i+1 < len {
|
|
opt_cx = sub_block(bcx, "match_case");
|
|
match kind {
|
|
single => Br(bcx, opt_cx.llbb),
|
|
switch => {
|
|
match trans_opt(bcx, opt) {
|
|
single_result(r) => {
|
|
unsafe {
|
|
llvm::LLVMAddCase(sw, r.val, opt_cx.llbb);
|
|
bcx = r.bcx;
|
|
}
|
|
}
|
|
_ => {
|
|
bcx.sess().bug(
|
|
"in compile_submatch, expected \
|
|
trans_opt to return a single_result")
|
|
}
|
|
}
|
|
}
|
|
compare => {
|
|
let t = node_id_type(bcx, pat_id);
|
|
let Result {bcx: after_cx, val: matches} = {
|
|
do with_scope_result(bcx, None,
|
|
"compare_scope") |bcx| {
|
|
match trans_opt(bcx, opt) {
|
|
single_result(
|
|
Result {bcx, val}) => {
|
|
compare_values(bcx, test_val, val, t)
|
|
}
|
|
lower_bound(
|
|
Result {bcx, val}) => {
|
|
compare_scalar_types(
|
|
bcx, test_val, val,
|
|
t, ast::BiGe)
|
|
}
|
|
range_result(
|
|
Result {val: vbegin, _},
|
|
Result {bcx, val: vend}) => {
|
|
let Result {bcx, val: llge} =
|
|
compare_scalar_types(
|
|
bcx, test_val,
|
|
vbegin, t, ast::BiGe);
|
|
let Result {bcx, val: llle} =
|
|
compare_scalar_types(
|
|
bcx, test_val, vend,
|
|
t, ast::BiLe);
|
|
rslt(bcx, And(bcx, llge, llle))
|
|
}
|
|
}
|
|
}
|
|
};
|
|
bcx = sub_block(after_cx, "compare_next");
|
|
CondBr(after_cx, matches, opt_cx.llbb, bcx.llbb);
|
|
}
|
|
compare_vec_len => {
|
|
let Result {bcx: after_cx, val: matches} = {
|
|
do with_scope_result(bcx, None,
|
|
"compare_vec_len_scope") |bcx| {
|
|
match trans_opt(bcx, opt) {
|
|
single_result(
|
|
Result {bcx, val}) => {
|
|
let value = compare_scalar_values(
|
|
bcx, test_val, val,
|
|
signed_int, ast::BiEq);
|
|
rslt(bcx, value)
|
|
}
|
|
lower_bound(
|
|
Result {bcx, val: val}) => {
|
|
let value = compare_scalar_values(
|
|
bcx, test_val, val,
|
|
signed_int, ast::BiGe);
|
|
rslt(bcx, value)
|
|
}
|
|
range_result(
|
|
Result {val: vbegin, _},
|
|
Result {bcx, val: vend}) => {
|
|
let llge =
|
|
compare_scalar_values(
|
|
bcx, test_val,
|
|
vbegin, signed_int, ast::BiGe);
|
|
let llle =
|
|
compare_scalar_values(
|
|
bcx, test_val, vend,
|
|
signed_int, ast::BiLe);
|
|
rslt(bcx, And(bcx, llge, llle))
|
|
}
|
|
}
|
|
}
|
|
};
|
|
bcx = sub_block(after_cx, "compare_vec_len_next");
|
|
|
|
// If none of these subcases match, move on to the
|
|
// next condition.
|
|
branch_chk = JumpToBasicBlock(bcx.llbb);
|
|
CondBr(after_cx, matches, opt_cx.llbb, bcx.llbb);
|
|
}
|
|
_ => ()
|
|
}
|
|
} else if kind == compare || kind == compare_vec_len {
|
|
Br(bcx, else_cx.llbb);
|
|
}
|
|
|
|
let mut size = 0u;
|
|
let mut unpacked = ~[];
|
|
match *opt {
|
|
var(disr_val, repr) => {
|
|
let ExtractedBlock {vals: argvals, bcx: new_bcx} =
|
|
extract_variant_args(opt_cx, repr, disr_val, val);
|
|
size = argvals.len();
|
|
unpacked = argvals;
|
|
opt_cx = new_bcx;
|
|
}
|
|
vec_len(n, vt, _) => {
|
|
let (n, slice) = match vt {
|
|
vec_len_ge(i) => (n + 1u, Some(i)),
|
|
vec_len_eq => (n, None)
|
|
};
|
|
let args = extract_vec_elems(opt_cx, pat_span, pat_id, n,
|
|
slice, val, test_val);
|
|
size = args.vals.len();
|
|
unpacked = args.vals.clone();
|
|
opt_cx = args.bcx;
|
|
}
|
|
lit(_) | range(_, _) => ()
|
|
}
|
|
let opt_ms = enter_opt(opt_cx, m, opt, col, size, val);
|
|
let opt_vals = vec::append(unpacked, vals_left);
|
|
compile_submatch(opt_cx, opt_ms, opt_vals, branch_chk);
|
|
}
|
|
|
|
// Compile the fall-through case, if any
|
|
if !exhaustive {
|
|
if kind == compare || kind == compare_vec_len {
|
|
Br(bcx, else_cx.llbb);
|
|
}
|
|
if kind != single {
|
|
compile_submatch(else_cx, defaults, vals_left, chk);
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn trans_match(bcx: @mut Block,
|
|
match_expr: &ast::Expr,
|
|
discr_expr: &ast::Expr,
|
|
arms: &[ast::Arm],
|
|
dest: Dest) -> @mut Block {
|
|
let _icx = push_ctxt("match::trans_match");
|
|
do with_scope(bcx, match_expr.info(), "match") |bcx| {
|
|
trans_match_inner(bcx, discr_expr, arms, dest)
|
|
}
|
|
}
|
|
|
|
fn create_bindings_map(bcx: @mut Block, pat: @ast::Pat) -> BindingsMap {
|
|
// Create the bindings map, which is a mapping from each binding name
|
|
// to an alloca() that will be the value for that local variable.
|
|
// Note that we use the names because each binding will have many ids
|
|
// from the various alternatives.
|
|
let ccx = bcx.ccx();
|
|
let tcx = bcx.tcx();
|
|
let mut bindings_map = HashMap::new();
|
|
do pat_bindings(tcx.def_map, pat) |bm, p_id, span, path| {
|
|
let ident = path_to_ident(path);
|
|
let variable_ty = node_id_type(bcx, p_id);
|
|
let llvariable_ty = type_of::type_of(ccx, variable_ty);
|
|
|
|
let llmatch;
|
|
let trmode;
|
|
match bm {
|
|
ast::BindInfer => {
|
|
// in this case, the final type of the variable will be T,
|
|
// but during matching we need to store a *T as explained
|
|
// above
|
|
llmatch = alloca(bcx, llvariable_ty.ptr_to(), "__llmatch");
|
|
trmode = TrByValue(alloca(bcx, llvariable_ty,
|
|
bcx.ident(ident)));
|
|
}
|
|
ast::BindByRef(_) => {
|
|
llmatch = alloca(bcx, llvariable_ty, bcx.ident(ident));
|
|
trmode = TrByRef;
|
|
}
|
|
};
|
|
bindings_map.insert(ident, BindingInfo {
|
|
llmatch: llmatch,
|
|
trmode: trmode,
|
|
id: p_id,
|
|
span: span,
|
|
ty: variable_ty
|
|
});
|
|
}
|
|
return bindings_map;
|
|
}
|
|
|
|
fn trans_match_inner(scope_cx: @mut Block,
|
|
discr_expr: &ast::Expr,
|
|
arms: &[ast::Arm],
|
|
dest: Dest) -> @mut Block {
|
|
let _icx = push_ctxt("match::trans_match_inner");
|
|
let mut bcx = scope_cx;
|
|
let tcx = bcx.tcx();
|
|
|
|
let discr_datum = unpack_datum!(bcx, {
|
|
expr::trans_to_datum(bcx, discr_expr)
|
|
});
|
|
if bcx.unreachable {
|
|
return bcx;
|
|
}
|
|
|
|
let mut arm_datas = ~[];
|
|
let mut matches = ~[];
|
|
for arm in arms.iter() {
|
|
let body = scope_block(bcx, arm.body.info(), "case_body");
|
|
let bindings_map = create_bindings_map(bcx, arm.pats[0]);
|
|
let arm_data = ArmData {
|
|
bodycx: body,
|
|
arm: arm,
|
|
bindings_map: @bindings_map
|
|
};
|
|
arm_datas.push(arm_data.clone());
|
|
for p in arm.pats.iter() {
|
|
matches.push(Match {
|
|
pats: ~[*p],
|
|
data: arm_data.clone(),
|
|
bound_ptrs: ~[],
|
|
});
|
|
}
|
|
}
|
|
|
|
let t = node_id_type(bcx, discr_expr.id);
|
|
let chk = {
|
|
if ty::type_is_empty(tcx, t) {
|
|
// Special case for empty types
|
|
let fail_cx = @mut None;
|
|
let fail_handler = @DynamicFailureHandler {
|
|
bcx: scope_cx,
|
|
sp: discr_expr.span,
|
|
msg: @"scrutinizing value that can't exist",
|
|
finished: fail_cx,
|
|
} as @CustomFailureHandler;
|
|
CustomFailureHandlerClass(fail_handler)
|
|
} else {
|
|
Infallible
|
|
}
|
|
};
|
|
let lldiscr = discr_datum.to_ref_llval(bcx);
|
|
compile_submatch(bcx, matches, [lldiscr], chk);
|
|
|
|
let mut arm_cxs = ~[];
|
|
for arm_data in arm_datas.iter() {
|
|
let mut bcx = arm_data.bodycx;
|
|
|
|
// If this arm has a guard, then the various by-value bindings have
|
|
// already been copied into their homes. If not, we do it here. This
|
|
// is just to reduce code space. See extensive comment at the start
|
|
// of the file for more details.
|
|
if arm_data.arm.guard.is_none() {
|
|
bcx = store_non_ref_bindings(bcx, arm_data.bindings_map, None);
|
|
}
|
|
|
|
// insert bindings into the lllocals map and add cleanups
|
|
bcx = insert_lllocals(bcx, arm_data.bindings_map, true);
|
|
|
|
bcx = controlflow::trans_block(bcx, &arm_data.arm.body, dest);
|
|
bcx = trans_block_cleanups(bcx, block_cleanups(arm_data.bodycx));
|
|
arm_cxs.push(bcx);
|
|
}
|
|
|
|
bcx = controlflow::join_blocks(scope_cx, arm_cxs);
|
|
return bcx;
|
|
}
|
|
|
|
enum IrrefutablePatternBindingMode {
|
|
// Stores the association between node ID and LLVM value in `lllocals`.
|
|
BindLocal,
|
|
// Stores the association between node ID and LLVM value in `llargs`.
|
|
BindArgument
|
|
}
|
|
|
|
pub fn store_local(bcx: @mut Block,
|
|
pat: @ast::Pat,
|
|
opt_init_expr: Option<@ast::Expr>)
|
|
-> @mut Block {
|
|
/*!
|
|
* Generates code for a local variable declaration like
|
|
* `let <pat>;` or `let <pat> = <opt_init_expr>`.
|
|
*/
|
|
let _icx = push_ctxt("match::store_local");
|
|
let mut bcx = bcx;
|
|
|
|
return match opt_init_expr {
|
|
Some(init_expr) => {
|
|
// Optimize the "let x = expr" case. This just writes
|
|
// the result of evaluating `expr` directly into the alloca
|
|
// for `x`. Often the general path results in similar or the
|
|
// same code post-optimization, but not always. In particular,
|
|
// in unsafe code, you can have expressions like
|
|
//
|
|
// let x = intrinsics::uninit();
|
|
//
|
|
// In such cases, the more general path is unsafe, because
|
|
// it assumes it is matching against a valid value.
|
|
match simple_identifier(pat) {
|
|
Some(path) => {
|
|
return mk_binding_alloca(
|
|
bcx, pat.id, path, BindLocal,
|
|
|bcx, _, llval| expr::trans_into(bcx, init_expr,
|
|
expr::SaveIn(llval)));
|
|
}
|
|
|
|
None => {}
|
|
}
|
|
|
|
// General path.
|
|
let init_datum =
|
|
unpack_datum!(
|
|
bcx,
|
|
expr::trans_to_datum(bcx, init_expr));
|
|
if ty::type_is_bot(expr_ty(bcx, init_expr)) {
|
|
create_dummy_locals(bcx, pat)
|
|
} else {
|
|
if bcx.sess().asm_comments() {
|
|
add_comment(bcx, "creating zeroable ref llval");
|
|
}
|
|
let llptr = init_datum.to_ref_llval(bcx);
|
|
return bind_irrefutable_pat(bcx, pat, llptr, BindLocal);
|
|
}
|
|
}
|
|
None => {
|
|
create_dummy_locals(bcx, pat)
|
|
}
|
|
};
|
|
|
|
fn create_dummy_locals(mut bcx: @mut Block, pat: @ast::Pat) -> @mut Block {
|
|
// create dummy memory for the variables if we have no
|
|
// value to store into them immediately
|
|
let tcx = bcx.tcx();
|
|
do pat_bindings(tcx.def_map, pat) |_, p_id, _, path| {
|
|
bcx = mk_binding_alloca(
|
|
bcx, p_id, path, BindLocal,
|
|
|bcx, var_ty, llval| { zero_mem(bcx, llval, var_ty); bcx });
|
|
}
|
|
bcx
|
|
}
|
|
}
|
|
|
|
pub fn store_arg(mut bcx: @mut Block,
|
|
pat: @ast::Pat,
|
|
llval: ValueRef)
|
|
-> @mut Block {
|
|
/*!
|
|
* Generates code for argument patterns like `fn foo(<pat>: T)`.
|
|
* Creates entries in the `llargs` map for each of the bindings
|
|
* in `pat`.
|
|
*
|
|
* # Arguments
|
|
*
|
|
* - `pat` is the argument pattern
|
|
* - `llval` is a pointer to the argument value (in other words,
|
|
* if the argument type is `T`, then `llval` is a `T*`). In some
|
|
* cases, this code may zero out the memory `llval` points at.
|
|
*/
|
|
let _icx = push_ctxt("match::store_arg");
|
|
|
|
// We always need to cleanup the argument as we exit the fn scope.
|
|
// Note that we cannot do it before for fear of a fn like
|
|
// fn getaddr(~ref x: ~uint) -> *uint {....}
|
|
// (From test `run-pass/func-arg-ref-pattern.rs`)
|
|
let arg_ty = node_id_type(bcx, pat.id);
|
|
add_clean(bcx, llval, arg_ty);
|
|
|
|
// Debug information (the llvm.dbg.declare intrinsic to be precise) always expects to get an
|
|
// alloca, which only is the case on the general path, so lets disable the optimized path when
|
|
// debug info is enabled.
|
|
let fast_path = !bcx.ccx().sess.opts.extra_debuginfo && simple_identifier(pat).is_some();
|
|
|
|
if fast_path {
|
|
// Optimized path for `x: T` case. This just adopts
|
|
// `llval` wholesale as the pointer for `x`, avoiding the
|
|
// general logic which may copy out of `llval`.
|
|
bcx.fcx.llargs.insert(pat.id, llval);
|
|
} else {
|
|
// General path. Copy out the values that are used in the
|
|
// pattern.
|
|
bcx = bind_irrefutable_pat(bcx, pat, llval, BindArgument);
|
|
}
|
|
|
|
return bcx;
|
|
}
|
|
|
|
fn mk_binding_alloca(mut bcx: @mut Block,
|
|
p_id: ast::NodeId,
|
|
path: &ast::Path,
|
|
binding_mode: IrrefutablePatternBindingMode,
|
|
populate: &fn(@mut Block, ty::t, ValueRef) -> @mut Block) -> @mut Block {
|
|
let var_ty = node_id_type(bcx, p_id);
|
|
let ident = ast_util::path_to_ident(path);
|
|
let llval = alloc_ty(bcx, var_ty, bcx.ident(ident));
|
|
bcx = populate(bcx, var_ty, llval);
|
|
let llmap = match binding_mode {
|
|
BindLocal => bcx.fcx.lllocals,
|
|
BindArgument => bcx.fcx.llargs
|
|
};
|
|
llmap.insert(p_id, llval);
|
|
add_clean(bcx, llval, var_ty);
|
|
return bcx;
|
|
}
|
|
|
|
fn bind_irrefutable_pat(bcx: @mut Block,
|
|
pat: @ast::Pat,
|
|
val: ValueRef,
|
|
binding_mode: IrrefutablePatternBindingMode)
|
|
-> @mut Block {
|
|
/*!
|
|
* A simple version of the pattern matching code that only handles
|
|
* irrefutable patterns. This is used in let/argument patterns,
|
|
* not in match statements. Unifying this code with the code above
|
|
* sounds nice, but in practice it produces very inefficient code,
|
|
* since the match code is so much more general. In most cases,
|
|
* LLVM is able to optimize the code, but it causes longer compile
|
|
* times and makes the generated code nigh impossible to read.
|
|
*
|
|
* # Arguments
|
|
* - bcx: starting basic block context
|
|
* - pat: the irrefutable pattern being matched.
|
|
* - val: a pointer to the value being matched. If pat matches a value
|
|
* of type T, then this is a T*. If the value is moved from `pat`,
|
|
* then `*pat` will be zeroed; otherwise, it's existing cleanup
|
|
* applies.
|
|
* - binding_mode: is this for an argument or a local variable?
|
|
*/
|
|
|
|
debug!("bind_irrefutable_pat(bcx={}, pat={}, binding_mode={:?})",
|
|
bcx.to_str(),
|
|
pat.repr(bcx.tcx()),
|
|
binding_mode);
|
|
|
|
if bcx.sess().asm_comments() {
|
|
add_comment(bcx, format!("bind_irrefutable_pat(pat={})",
|
|
pat.repr(bcx.tcx())));
|
|
}
|
|
|
|
let _indenter = indenter();
|
|
|
|
let _icx = push_ctxt("alt::bind_irrefutable_pat");
|
|
let mut bcx = bcx;
|
|
let tcx = bcx.tcx();
|
|
let ccx = bcx.ccx();
|
|
match pat.node {
|
|
ast::PatIdent(pat_binding_mode, ref path, inner) => {
|
|
if pat_is_binding(tcx.def_map, pat) {
|
|
// Allocate the stack slot where the value of this
|
|
// binding will live and place it into the appropriate
|
|
// map.
|
|
bcx = mk_binding_alloca(
|
|
bcx, pat.id, path, binding_mode,
|
|
|bcx, variable_ty, llvariable_val| {
|
|
match pat_binding_mode {
|
|
ast::BindInfer => {
|
|
// By value binding: move the value that `val`
|
|
// points at into the binding's stack slot.
|
|
let datum = Datum {val: val,
|
|
ty: variable_ty,
|
|
mode: ByRef(ZeroMem)};
|
|
datum.store_to(bcx, INIT, llvariable_val)
|
|
}
|
|
|
|
ast::BindByRef(_) => {
|
|
// By ref binding: the value of the variable
|
|
// is the pointer `val` itself.
|
|
Store(bcx, val, llvariable_val);
|
|
bcx
|
|
}
|
|
}
|
|
});
|
|
}
|
|
|
|
for &inner_pat in inner.iter() {
|
|
bcx = bind_irrefutable_pat(bcx, inner_pat, val, binding_mode);
|
|
}
|
|
}
|
|
ast::PatEnum(_, ref sub_pats) => {
|
|
match bcx.tcx().def_map.find(&pat.id) {
|
|
Some(&ast::DefVariant(enum_id, var_id, _)) => {
|
|
let repr = adt::represent_node(bcx, pat.id);
|
|
let vinfo = ty::enum_variant_with_id(ccx.tcx,
|
|
enum_id,
|
|
var_id);
|
|
let args = extract_variant_args(bcx,
|
|
repr,
|
|
vinfo.disr_val,
|
|
val);
|
|
for sub_pat in sub_pats.iter() {
|
|
for (i, argval) in args.vals.iter().enumerate() {
|
|
bcx = bind_irrefutable_pat(bcx, sub_pat[i],
|
|
*argval, binding_mode);
|
|
}
|
|
}
|
|
}
|
|
Some(&ast::DefFn(*)) |
|
|
Some(&ast::DefStruct(*)) => {
|
|
match *sub_pats {
|
|
None => {
|
|
// This is a unit-like struct. Nothing to do here.
|
|
}
|
|
Some(ref elems) => {
|
|
// This is the tuple struct case.
|
|
let repr = adt::represent_node(bcx, pat.id);
|
|
for (i, elem) in elems.iter().enumerate() {
|
|
let fldptr = adt::trans_field_ptr(bcx, repr,
|
|
val, 0, i);
|
|
bcx = bind_irrefutable_pat(bcx, *elem,
|
|
fldptr, binding_mode);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
Some(&ast::DefStatic(_, false)) => {
|
|
}
|
|
_ => {
|
|
// Nothing to do here.
|
|
}
|
|
}
|
|
}
|
|
ast::PatStruct(_, ref fields, _) => {
|
|
let tcx = bcx.tcx();
|
|
let pat_ty = node_id_type(bcx, pat.id);
|
|
let pat_repr = adt::represent_type(bcx.ccx(), pat_ty);
|
|
do expr::with_field_tys(tcx, pat_ty, None) |discr, field_tys| {
|
|
for f in fields.iter() {
|
|
let ix = ty::field_idx_strict(tcx, f.ident.name, field_tys);
|
|
let fldptr = adt::trans_field_ptr(bcx, pat_repr, val,
|
|
discr, ix);
|
|
bcx = bind_irrefutable_pat(bcx, f.pat, fldptr, binding_mode);
|
|
}
|
|
}
|
|
}
|
|
ast::PatTup(ref elems) => {
|
|
let repr = adt::represent_node(bcx, pat.id);
|
|
for (i, elem) in elems.iter().enumerate() {
|
|
let fldptr = adt::trans_field_ptr(bcx, repr, val, 0, i);
|
|
bcx = bind_irrefutable_pat(bcx, *elem, fldptr, binding_mode);
|
|
}
|
|
}
|
|
ast::PatBox(inner) | ast::PatUniq(inner) => {
|
|
let pat_ty = node_id_type(bcx, pat.id);
|
|
let llbox = Load(bcx, val);
|
|
let unboxed = match ty::get(pat_ty).sty {
|
|
ty::ty_uniq(*) if !ty::type_contents(bcx.tcx(), pat_ty).contains_managed() => llbox,
|
|
_ => GEPi(bcx, llbox, [0u, abi::box_field_body])
|
|
};
|
|
bcx = bind_irrefutable_pat(bcx, inner, unboxed, binding_mode);
|
|
}
|
|
ast::PatRegion(inner) => {
|
|
let loaded_val = Load(bcx, val);
|
|
bcx = bind_irrefutable_pat(bcx, inner, loaded_val, binding_mode);
|
|
}
|
|
ast::PatVec(*) => {
|
|
bcx.tcx().sess.span_bug(
|
|
pat.span,
|
|
format!("vector patterns are never irrefutable!"));
|
|
}
|
|
ast::PatWild | ast::PatLit(_) | ast::PatRange(_, _) => ()
|
|
}
|
|
return bcx;
|
|
}
|
|
|
|
fn simple_identifier<'a>(pat: &'a ast::Pat) -> Option<&'a ast::Path> {
|
|
match pat.node {
|
|
ast::PatIdent(ast::BindInfer, ref path, None) => {
|
|
Some(path)
|
|
}
|
|
_ => {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|