861 lines
29 KiB
Rust
861 lines
29 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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* A `Datum` contains all the information you need to describe the LLVM
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* translation of a Rust value. It describes where the value is stored,
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* what Rust type the value has, whether it is addressed by reference,
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* and so forth.
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*
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* The idea of a datum is that, to the extent possible, you should not
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* care about these details, but rather use the methods on the Datum
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* type to "do what you want to do". For example, you can simply call
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* `copy_to()` or `move_to()` to copy or move the value into a new
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* home.
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*
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* # Datum location
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*
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* The primary two fields of a datum are the `val` and the `mode`.
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* The `val` is an LLVM value ref. It may either *be the value* that
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* is being tracked, or it may be a *pointer to the value being
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* tracked*. This is specified in the `mode` field, which can either
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* be `ByValue` or `ByRef`, respectively. The (Rust) type of the
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* value stored in the datum is indicated in the field `ty`.
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*
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* Generally speaking, you probably do not want to access the `val` field
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* unless you know what mode the value is in. Instead you should use one
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* of the following accessors:
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*
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* - `to_value_llval()` converts to by-value
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* - `to_ref_llval()` converts to by-ref, allocating a stack slot if necessary
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* - `to_appropriate_llval()` converts to by-value if this is an
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* immediate type, by-ref otherwise. This is particularly
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* convenient for interfacing with the various code floating around
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* that predates datums.
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*
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* # Datum cleanup styles
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*
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* Each datum carries with it an idea of how its value will be cleaned
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* up. This is primarily determined by the mode: a `ByValue` datum
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* will always be cleaned up by revoking cleanup using
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* `revoke_clean()`, because there is no other option. By ref datums
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* can sometimes be cleaned up via `revoke_clean` (in particular,
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* by-ref datums that originated from rvalues), but sometimes they
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* must be zeroed. This is indicated by the `DatumCleanup`
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* parameter. Note that zeroing a by-ref datum *always works* to
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* cancel the cleanup, but using `revoke_clean` is preferable since
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* there is no runtime cost. Some older parts of the code (notably
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* `match_`, at least at the time of this writing) rely on this and
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* only use zeroing.
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*
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* # Copying, moving, and storing
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*
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* There are three methods for moving the value into a new
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* location:
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*
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* - `copy_to()` will copy the value into a new location, meaning that
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* the value is first mem-copied and then the new location is "taken"
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* via the take glue, in effect creating a deep clone.
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*
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* - `move_to()` will copy the value, meaning that the value is mem-copied
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* into its new home and then the cleanup on the this datum is revoked.
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* This is a "shallow" clone. After `move_to()`, the current datum
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* is invalid and should no longer be used.
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*
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* - `store_to()` either performs a copy or a move depending on the
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* Rust type of the datum.
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*
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* # Scratch datum
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*
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* Sometimes you just need some temporary scratch space. The
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* `scratch_datum()` function will yield you up a by-ref datum that
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* points into the stack. It's your responsibility to ensure that
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* whatever you put in there gets cleaned up etc.
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*
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* # Other actions
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*
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* There are various other helper methods on Datum, such as `deref()`,
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* `get_base_and_len()` and so forth. These are documented on the
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* methods themselves. Most are only suitable for some types of
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* values. */
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use lib;
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use lib::llvm::ValueRef;
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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::common::*;
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use middle::trans::common;
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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::write_guard;
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use middle::ty;
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use util::common::indenter;
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use util::ppaux::ty_to_str;
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use std::uint;
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use syntax::ast;
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use syntax::codemap::Span;
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use syntax::parse::token::special_idents;
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#[deriving(Eq)]
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pub enum CopyAction {
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INIT,
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DROP_EXISTING
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}
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pub struct Datum {
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/// The llvm value. This is either a pointer to the Rust value or
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/// the value itself, depending on `mode` below.
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val: ValueRef,
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/// The rust type of the value.
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ty: ty::t,
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/// Indicates whether this is by-ref or by-value.
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mode: DatumMode,
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}
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pub struct DatumBlock {
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bcx: @mut Block,
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datum: Datum,
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}
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#[deriving(Eq, IterBytes)]
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pub enum DatumMode {
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/// `val` is a pointer to the actual value (and thus has type *T).
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/// The argument indicates how to cancel cleanup of this datum if
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/// the value is moved elsewhere, which can either be by zeroing
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/// the memory or by canceling a registered cleanup.
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ByRef(DatumCleanup),
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/// `val` is the actual value (*only used for immediates* like ints, ptrs)
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ByValue,
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}
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impl DatumMode {
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pub fn is_by_ref(&self) -> bool {
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match *self { ByRef(_) => true, ByValue => false }
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}
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pub fn is_by_value(&self) -> bool {
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match *self { ByRef(_) => false, ByValue => true }
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}
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}
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/// See `Datum cleanup styles` section at the head of this module.
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#[deriving(Eq, IterBytes)]
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pub enum DatumCleanup {
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RevokeClean,
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ZeroMem
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}
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pub fn immediate_rvalue(val: ValueRef, ty: ty::t) -> Datum {
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return Datum {val: val, ty: ty, mode: ByValue};
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}
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pub fn immediate_rvalue_bcx(bcx: @mut Block,
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val: ValueRef,
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ty: ty::t)
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-> DatumBlock {
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return DatumBlock {bcx: bcx, datum: immediate_rvalue(val, ty)};
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}
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pub fn scratch_datum(bcx: @mut Block, ty: ty::t, name: &str, zero: bool) -> Datum {
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/*!
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* Allocates temporary space on the stack using alloca() and
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* returns a by-ref Datum pointing to it. If `zero` is true, the
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* space will be zeroed when it is allocated; this is normally not
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* necessary, but in the case of automatic rooting in match
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* statements it is possible to have temporaries that may not get
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* initialized if a certain arm is not taken, so we must zero
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* them. You must arrange any cleanups etc yourself!
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*/
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let llty = type_of::type_of(bcx.ccx(), ty);
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let scratch = alloca_maybe_zeroed(bcx, llty, name, zero);
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Datum { val: scratch, ty: ty, mode: ByRef(RevokeClean) }
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}
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pub fn appropriate_mode(tcx: ty::ctxt, ty: ty::t) -> DatumMode {
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/*!
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* Indicates the "appropriate" mode for this value,
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* which is either by ref or by value, depending
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* on whether type is immediate or not.
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*/
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if ty::type_is_voidish(ty) {
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ByValue
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} else if ty::type_is_immediate(tcx, ty) {
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ByValue
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} else {
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ByRef(RevokeClean)
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}
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}
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impl Datum {
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pub fn store_to(&self,
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bcx: @mut Block,
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action: CopyAction,
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dst: ValueRef)
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-> @mut Block {
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/*!
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*
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* Stores this value into its final home. This moves if
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* `id` is located in the move table, but copies otherwise.
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*/
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if ty::type_moves_by_default(bcx.tcx(), self.ty) {
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self.move_to(bcx, action, dst)
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} else {
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self.copy_to(bcx, action, dst)
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}
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}
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pub fn store_to_dest(&self,
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bcx: @mut Block,
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dest: expr::Dest)
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-> @mut Block {
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match dest {
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expr::Ignore => {
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return bcx;
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}
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expr::SaveIn(addr) => {
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return self.store_to(bcx, INIT, addr);
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}
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}
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}
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pub fn store_to_datum(&self,
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bcx: @mut Block,
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action: CopyAction,
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datum: Datum)
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-> @mut Block {
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debug!("store_to_datum(self=%s, action=%?, datum=%s)",
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self.to_str(bcx.ccx()), action, datum.to_str(bcx.ccx()));
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assert!(datum.mode.is_by_ref());
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self.store_to(bcx, action, datum.val)
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}
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pub fn move_to_datum(&self, bcx: @mut Block, action: CopyAction, datum: Datum)
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-> @mut Block {
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assert!(datum.mode.is_by_ref());
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self.move_to(bcx, action, datum.val)
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}
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pub fn copy_to_datum(&self, bcx: @mut Block, action: CopyAction, datum: Datum)
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-> @mut Block {
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assert!(datum.mode.is_by_ref());
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self.copy_to(bcx, action, datum.val)
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}
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pub fn copy_to(&self, bcx: @mut Block, action: CopyAction, dst: ValueRef)
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-> @mut Block {
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/*!
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*
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* Copies the value into `dst`, which should be a pointer to a
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* memory location suitable for `self.ty`. You PROBABLY want
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* `store_to()` instead, which will move if possible but copy if
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* neccessary. */
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let _icx = push_ctxt("copy_to");
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if ty::type_is_voidish(self.ty) {
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return bcx;
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}
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debug!("copy_to(self=%s, action=%?, dst=%s)",
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self.to_str(bcx.ccx()), action, bcx.val_to_str(dst));
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// Watch out for the case where we are writing the copying the
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// value into the same location we read it out from. We want
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// to avoid the case where we drop the existing value, which
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// frees it, and then overwrite it with itself (which has been
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// freed).
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if action == DROP_EXISTING &&
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ty::type_needs_drop(bcx.tcx(), self.ty)
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{
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match self.mode {
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ByRef(_) => {
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let cast = PointerCast(bcx, dst, val_ty(self.val));
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let cmp = ICmp(bcx, lib::llvm::IntNE, cast, self.val);
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do with_cond(bcx, cmp) |bcx| {
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self.copy_to_no_check(bcx, action, dst)
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}
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}
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ByValue => {
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self.copy_to_no_check(bcx, action, dst)
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}
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}
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} else {
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self.copy_to_no_check(bcx, action, dst)
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}
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}
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pub fn copy_to_no_check(&self,
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bcx: @mut Block,
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action: CopyAction,
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dst: ValueRef)
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-> @mut Block {
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/*!
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*
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* A helper for `copy_to()` which does not check to see if we
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* are copying to/from the same value. */
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let _icx = push_ctxt("copy_to_no_check");
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let mut bcx = bcx;
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if action == DROP_EXISTING {
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bcx = glue::drop_ty(bcx, dst, self.ty);
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}
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match self.mode {
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ByValue => {
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Store(bcx, self.val, dst);
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}
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ByRef(_) => {
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memcpy_ty(bcx, dst, self.val, self.ty);
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}
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}
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return glue::take_ty(bcx, dst, self.ty);
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}
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// This works like copy_val, except that it deinitializes the source.
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// Since it needs to zero out the source, src also needs to be an lval.
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//
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pub fn move_to(&self, bcx: @mut Block, action: CopyAction, dst: ValueRef)
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-> @mut Block {
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let _icx = push_ctxt("move_to");
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let mut bcx = bcx;
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debug!("move_to(self=%s, action=%?, dst=%s)",
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self.to_str(bcx.ccx()), action, bcx.val_to_str(dst));
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if ty::type_is_voidish(self.ty) {
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return bcx;
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}
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if action == DROP_EXISTING {
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bcx = glue::drop_ty(bcx, dst, self.ty);
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}
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match self.mode {
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ByRef(_) => {
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memcpy_ty(bcx, dst, self.val, self.ty);
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}
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ByValue => {
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Store(bcx, self.val, dst);
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}
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}
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self.cancel_clean(bcx);
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return bcx;
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}
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pub fn add_clean(&self, bcx: @mut Block) {
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/*!
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* Schedules this datum for cleanup in `bcx`. The datum
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* must be an rvalue.
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*/
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match self.mode {
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ByValue => {
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add_clean_temp_immediate(bcx, self.val, self.ty);
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}
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ByRef(RevokeClean) => {
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add_clean_temp_mem(bcx, self.val, self.ty);
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}
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ByRef(ZeroMem) => {
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bcx.tcx().sess.bug(
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fmt!("Cannot add clean to a 'zero-mem' datum"));
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}
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}
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}
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pub fn cancel_clean(&self, bcx: @mut Block) {
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if ty::type_needs_drop(bcx.tcx(), self.ty) {
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match self.mode {
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ByValue |
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ByRef(RevokeClean) => {
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revoke_clean(bcx, self.val);
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}
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ByRef(ZeroMem) => {
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// Lvalues which potentially need to be dropped
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// must be passed by ref, so that we can zero them
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// out.
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assert!(self.mode.is_by_ref());
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zero_mem(bcx, self.val, self.ty);
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}
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}
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}
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}
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pub fn to_str(&self, ccx: &CrateContext) -> ~str {
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fmt!("Datum { val=%s, ty=%s, mode=%? }",
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ccx.tn.val_to_str(self.val),
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ty_to_str(ccx.tcx, self.ty),
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self.mode)
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}
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pub fn to_value_datum(&self, bcx: @mut Block) -> Datum {
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/*!
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*
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* Yields a by-value form of this datum. This may involve
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* creation of a temporary stack slot. The value returned by
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* this function is not separately rooted from this datum, so
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* it will not live longer than the current datum. */
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match self.mode {
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ByValue => *self,
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ByRef(_) => {
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Datum {val: self.to_value_llval(bcx), mode: ByValue,
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ty: self.ty}
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}
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}
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}
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pub fn to_value_llval(&self, bcx: @mut Block) -> ValueRef {
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/*!
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*
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* Yields the value itself. */
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if ty::type_is_voidish(self.ty) {
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C_nil()
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} else {
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match self.mode {
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ByValue => self.val,
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ByRef(_) => {
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if ty::type_is_bool(self.ty) {
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LoadRangeAssert(bcx, self.val, 0, 2, lib::llvm::True)
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} else {
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Load(bcx, self.val)
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}
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}
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}
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}
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}
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pub fn to_ref_datum(&self, bcx: @mut Block) -> Datum {
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/*!
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* Yields a by-ref form of this datum. This may involve
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* creation of a temporary stack slot. The value returned by
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* this function is not separately rooted from this datum, so
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* it will not live longer than the current datum.
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*/
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match self.mode {
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ByRef(_) => *self,
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ByValue => {
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Datum {val: self.to_ref_llval(bcx), mode: ByRef(RevokeClean),
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ty: self.ty}
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}
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}
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}
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pub fn to_ref_llval(&self, bcx: @mut Block) -> ValueRef {
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match self.mode {
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ByRef(_) => self.val,
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ByValue => {
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if ty::type_is_voidish(self.ty) {
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C_null(type_of::type_of(bcx.ccx(), self.ty).ptr_to())
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} else {
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let slot = alloc_ty(bcx, self.ty, "");
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Store(bcx, self.val, slot);
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slot
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}
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}
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}
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}
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pub fn to_zeroable_ref_llval(&self, bcx: @mut Block) -> ValueRef {
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/*!
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* Returns a by-ref llvalue that can be zeroed in order to
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* cancel cleanup. This is a kind of hokey bridge used
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* to adapt to the match code. Please don't use it for new code.
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*/
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match self.mode {
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// All by-ref datums are zeroable, even if we *could* just
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// cancel the cleanup.
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ByRef(_) => self.val,
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// By value datums can't be zeroed (where would you store
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// the zero?) so we have to spill them. Add a temp cleanup
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// for this spilled value and cancel the cleanup on this
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// current value.
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ByValue => {
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let slot = self.to_ref_llval(bcx);
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self.cancel_clean(bcx);
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add_clean_temp_mem(bcx, slot, self.ty);
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slot
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}
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}
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}
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pub fn appropriate_mode(&self, tcx: ty::ctxt) -> DatumMode {
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/*! See the `appropriate_mode()` function */
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appropriate_mode(tcx, self.ty)
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}
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pub fn to_appropriate_llval(&self, bcx: @mut Block) -> ValueRef {
|
|
/*!
|
|
*
|
|
* Yields an llvalue with the `appropriate_mode()`. */
|
|
|
|
match self.appropriate_mode(bcx.tcx()) {
|
|
ByValue => self.to_value_llval(bcx),
|
|
ByRef(_) => self.to_ref_llval(bcx)
|
|
}
|
|
}
|
|
|
|
pub fn to_appropriate_datum(&self, bcx: @mut Block) -> Datum {
|
|
/*!
|
|
*
|
|
* Yields a datum with the `appropriate_mode()`. */
|
|
|
|
match self.appropriate_mode(bcx.tcx()) {
|
|
ByValue => self.to_value_datum(bcx),
|
|
ByRef(_) => self.to_ref_datum(bcx)
|
|
}
|
|
}
|
|
|
|
pub fn get_element(&self,
|
|
bcx: @mut Block,
|
|
ty: ty::t,
|
|
source: DatumCleanup,
|
|
gep: &fn(ValueRef) -> ValueRef)
|
|
-> Datum {
|
|
let base_val = self.to_ref_llval(bcx);
|
|
Datum {
|
|
val: gep(base_val),
|
|
mode: ByRef(source),
|
|
ty: ty,
|
|
}
|
|
}
|
|
|
|
pub fn drop_val(&self, bcx: @mut Block) -> @mut Block {
|
|
if !ty::type_needs_drop(bcx.tcx(), self.ty) {
|
|
return bcx;
|
|
}
|
|
|
|
return match self.mode {
|
|
ByRef(_) => glue::drop_ty(bcx, self.val, self.ty),
|
|
ByValue => glue::drop_ty_immediate(bcx, self.val, self.ty)
|
|
};
|
|
}
|
|
|
|
pub fn box_body(&self, bcx: @mut Block) -> Datum {
|
|
/*!
|
|
*
|
|
* This datum must represent an @T or ~T box. Returns a new
|
|
* by-ref datum of type T, pointing at the contents. */
|
|
|
|
let (content_ty, header) = match ty::get(self.ty).sty {
|
|
ty::ty_box(mt) => (mt.ty, true),
|
|
ty::ty_uniq(mt) => (mt.ty, false),
|
|
ty::ty_evec(_, ty::vstore_uniq) | ty::ty_estr(ty::vstore_uniq) => {
|
|
let unit_ty = ty::sequence_element_type(bcx.tcx(), self.ty);
|
|
let unboxed_vec_ty = ty::mk_mut_unboxed_vec(bcx.tcx(), unit_ty);
|
|
(unboxed_vec_ty, true)
|
|
}
|
|
_ => {
|
|
bcx.tcx().sess.bug(fmt!(
|
|
"box_body() invoked on non-box type %s",
|
|
ty_to_str(bcx.tcx(), self.ty)));
|
|
}
|
|
};
|
|
|
|
if !header && !ty::type_contents(bcx.tcx(), content_ty).contains_managed() {
|
|
let ptr = self.to_value_llval(bcx);
|
|
let ty = type_of(bcx.ccx(), content_ty);
|
|
let body = PointerCast(bcx, ptr, ty.ptr_to());
|
|
Datum {val: body, ty: content_ty, mode: ByRef(ZeroMem)}
|
|
} else { // has a header
|
|
let ptr = self.to_value_llval(bcx);
|
|
let body = opaque_box_body(bcx, content_ty, ptr);
|
|
Datum {val: body, ty: content_ty, mode: ByRef(ZeroMem)}
|
|
}
|
|
}
|
|
|
|
pub fn to_rptr(&self, bcx: @mut Block) -> Datum {
|
|
//! Returns a new datum of region-pointer type containing the
|
|
//! the same ptr as this datum (after converting to by-ref
|
|
//! using `to_ref_llval()`).
|
|
|
|
// Convert to ref, yielding lltype *T. Then create a Rust
|
|
// type &'static T (which translates to *T). Construct new
|
|
// result (which will be by-value). Note that it is not
|
|
// significant *which* region we pick here.
|
|
let llval = self.to_ref_llval(bcx);
|
|
let rptr_ty = ty::mk_imm_rptr(bcx.tcx(), ty::re_static,
|
|
self.ty);
|
|
Datum {val: llval, ty: rptr_ty, mode: ByValue}
|
|
}
|
|
|
|
/// bcx: Block wherein to generate insns.
|
|
/// span: Location where deref occurs.
|
|
/// expr_id: ID of deref expr.
|
|
/// derefs: Number of times deref'd already.
|
|
/// is_auto: If true, only deref if auto-derefable.
|
|
pub fn try_deref(&self,
|
|
bcx: @mut Block,
|
|
span: Span,
|
|
expr_id: ast::NodeId,
|
|
derefs: uint,
|
|
is_auto: bool)
|
|
-> (Option<Datum>, @mut Block) {
|
|
let ccx = bcx.ccx();
|
|
|
|
debug!("try_deref(expr_id=%?, derefs=%?, is_auto=%b, self=%?)",
|
|
expr_id, derefs, is_auto, self.to_str(bcx.ccx()));
|
|
|
|
let bcx =
|
|
write_guard::root_and_write_guard(
|
|
self, bcx, span, expr_id, derefs);
|
|
|
|
match ty::get(self.ty).sty {
|
|
ty::ty_box(_) | ty::ty_uniq(_) => {
|
|
return (Some(self.box_body(bcx)), bcx);
|
|
}
|
|
ty::ty_ptr(mt) => {
|
|
if is_auto { // unsafe ptrs are not AUTO-derefable
|
|
return (None, bcx);
|
|
} else {
|
|
return (Some(deref_ptr(bcx, self, mt.ty)), bcx);
|
|
}
|
|
}
|
|
ty::ty_rptr(_, mt) => {
|
|
return (Some(deref_ptr(bcx, self, mt.ty)), bcx);
|
|
}
|
|
ty::ty_enum(did, ref substs) => {
|
|
// Check whether this enum is a newtype enum:
|
|
let variants = ty::enum_variants(ccx.tcx, did);
|
|
if (*variants).len() != 1 || variants[0].args.len() != 1 {
|
|
return (None, bcx);
|
|
}
|
|
|
|
let repr = adt::represent_type(ccx, self.ty);
|
|
let ty = ty::subst(ccx.tcx, substs, variants[0].args[0]);
|
|
return match self.mode {
|
|
ByRef(_) => {
|
|
// Recast lv.val as a pointer to the newtype
|
|
// rather than a ptr to the enum type.
|
|
(
|
|
Some(Datum {
|
|
val: adt::trans_field_ptr(bcx, repr, self.val,
|
|
0, 0),
|
|
ty: ty,
|
|
mode: ByRef(ZeroMem)
|
|
}),
|
|
bcx
|
|
)
|
|
}
|
|
ByValue => {
|
|
// Actually, this case cannot happen right
|
|
// now, because enums are never immediate.
|
|
assert!(ty::type_is_immediate(bcx.tcx(), ty));
|
|
(Some(Datum {ty: ty, ..*self}), bcx)
|
|
}
|
|
};
|
|
}
|
|
ty::ty_struct(did, ref substs) => {
|
|
// Check whether this struct is a newtype struct.
|
|
let fields = ty::struct_fields(ccx.tcx, did, substs);
|
|
if fields.len() != 1 || fields[0].ident !=
|
|
special_idents::unnamed_field {
|
|
return (None, bcx);
|
|
}
|
|
|
|
let repr = adt::represent_type(ccx, self.ty);
|
|
let ty = fields[0].mt.ty;
|
|
return match self.mode {
|
|
ByRef(_) => {
|
|
// Recast lv.val as a pointer to the newtype rather
|
|
// than a pointer to the struct type.
|
|
// FIXME #6572: This isn't correct for structs with
|
|
// destructors.
|
|
(
|
|
Some(Datum {
|
|
val: adt::trans_field_ptr(bcx, repr, self.val,
|
|
0, 0),
|
|
ty: ty,
|
|
mode: ByRef(ZeroMem)
|
|
}),
|
|
bcx
|
|
)
|
|
}
|
|
ByValue => {
|
|
assert!(ty::type_is_immediate(bcx.tcx(), ty));
|
|
(
|
|
Some(Datum {
|
|
val: ExtractValue(bcx, self.val, 0),
|
|
ty: ty,
|
|
mode: ByValue
|
|
}),
|
|
bcx
|
|
)
|
|
}
|
|
}
|
|
}
|
|
_ => { // not derefable.
|
|
return (None, bcx);
|
|
}
|
|
}
|
|
|
|
fn deref_ptr(bcx: @mut Block, lv: &Datum, ty: ty::t) -> Datum {
|
|
Datum {
|
|
val: lv.to_value_llval(bcx),
|
|
ty: ty,
|
|
mode: ByRef(ZeroMem)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// expr: The deref expression.
|
|
pub fn deref(&self, bcx: @mut Block, expr: &ast::Expr, derefs: uint)
|
|
-> DatumBlock {
|
|
match self.try_deref(bcx, expr.span, expr.id, derefs, false) {
|
|
(Some(lvres), bcx) => DatumBlock { bcx: bcx, datum: lvres },
|
|
(None, _) => {
|
|
bcx.ccx().sess.span_bug(expr.span,
|
|
"Cannot deref this expression");
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn autoderef(&self,
|
|
bcx: @mut Block,
|
|
span: Span,
|
|
expr_id: ast::NodeId,
|
|
max: uint)
|
|
-> DatumBlock {
|
|
let _icx = push_ctxt("autoderef");
|
|
|
|
debug!("autoderef(expr_id=%d, max=%?, self=%?)",
|
|
expr_id, max, self.to_str(bcx.ccx()));
|
|
let _indenter = indenter();
|
|
|
|
let mut datum = *self;
|
|
let mut derefs = 0u;
|
|
let mut bcx = bcx;
|
|
while derefs < max {
|
|
derefs += 1u;
|
|
match datum.try_deref(bcx, span, expr_id, derefs, true) {
|
|
(None, new_bcx) => { bcx = new_bcx; break }
|
|
(Some(datum_deref), new_bcx) => {
|
|
datum = datum_deref;
|
|
bcx = new_bcx;
|
|
}
|
|
}
|
|
}
|
|
|
|
// either we were asked to deref a specific number of times,
|
|
// in which case we should have, or we asked to deref as many
|
|
// times as we can
|
|
assert!(derefs == max || max == uint::max_value);
|
|
DatumBlock { bcx: bcx, datum: datum }
|
|
}
|
|
|
|
pub fn get_vec_base_and_len(&self,
|
|
mut bcx: @mut Block,
|
|
span: Span,
|
|
expr_id: ast::NodeId,
|
|
derefs: uint)
|
|
-> (@mut Block, ValueRef, ValueRef) {
|
|
//! Converts a vector into the slice pair. Performs rooting
|
|
//! and write guards checks.
|
|
|
|
// only imp't for @[] and @str, but harmless
|
|
bcx = write_guard::root_and_write_guard(self, bcx, span, expr_id, derefs);
|
|
let (base, len) = self.get_vec_base_and_len_no_root(bcx);
|
|
(bcx, base, len)
|
|
}
|
|
|
|
pub fn get_vec_base_and_len_no_root(&self, bcx: @mut Block)
|
|
-> (ValueRef, ValueRef) {
|
|
//! Converts a vector into the slice pair. Des not root
|
|
//! nor perform write guard checks.
|
|
|
|
let llval = self.to_appropriate_llval(bcx);
|
|
tvec::get_base_and_len(bcx, llval, self.ty)
|
|
}
|
|
|
|
pub fn root_and_write_guard(&self,
|
|
bcx: @mut Block,
|
|
span: Span,
|
|
expr_id: ast::NodeId,
|
|
derefs: uint)
|
|
-> @mut Block {
|
|
write_guard::root_and_write_guard(self, bcx, span, expr_id, derefs)
|
|
}
|
|
|
|
pub fn to_result(&self, bcx: @mut Block) -> common::Result {
|
|
rslt(bcx, self.to_appropriate_llval(bcx))
|
|
}
|
|
}
|
|
|
|
impl DatumBlock {
|
|
pub fn unpack(&self, bcx: &mut @mut Block) -> Datum {
|
|
*bcx = self.bcx;
|
|
return self.datum;
|
|
}
|
|
|
|
pub fn assert_by_ref(&self) -> DatumBlock {
|
|
assert!(self.datum.mode.is_by_ref());
|
|
*self
|
|
}
|
|
|
|
pub fn drop_val(&self) -> @mut Block {
|
|
self.datum.drop_val(self.bcx)
|
|
}
|
|
|
|
pub fn store_to(&self,
|
|
action: CopyAction,
|
|
dst: ValueRef)
|
|
-> @mut Block {
|
|
self.datum.store_to(self.bcx, action, dst)
|
|
}
|
|
|
|
pub fn copy_to(&self, action: CopyAction, dst: ValueRef) -> @mut Block {
|
|
self.datum.copy_to(self.bcx, action, dst)
|
|
}
|
|
|
|
pub fn move_to(&self, action: CopyAction, dst: ValueRef) -> @mut Block {
|
|
self.datum.move_to(self.bcx, action, dst)
|
|
}
|
|
|
|
pub fn to_value_llval(&self) -> ValueRef {
|
|
self.datum.to_value_llval(self.bcx)
|
|
}
|
|
|
|
pub fn to_result(&self) -> common::Result {
|
|
rslt(self.bcx, self.datum.to_appropriate_llval(self.bcx))
|
|
}
|
|
|
|
pub fn ccx(&self) -> @mut CrateContext {
|
|
self.bcx.ccx()
|
|
}
|
|
|
|
pub fn tcx(&self) -> ty::ctxt {
|
|
self.bcx.tcx()
|
|
}
|
|
|
|
pub fn to_str(&self) -> ~str {
|
|
self.datum.to_str(self.ccx())
|
|
}
|
|
}
|