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1 | // Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
2 | // file at the top-level directory of this distribution and at | |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
10 | ||
11 | //! See docs in build/expr/mod.rs | |
12 | ||
13 | use build::{BlockAnd, Builder}; | |
14 | use build::expr::category::Category; | |
15 | use hair::*; | |
16 | use repr::*; | |
17 | ||
b039eaaf | 18 | impl<'a,'tcx> Builder<'a,'tcx> { |
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19 | /// Compile `expr`, yielding an lvalue that we can move from etc. |
20 | pub fn as_lvalue<M>(&mut self, | |
21 | block: BasicBlock, | |
22 | expr: M) | |
b039eaaf SL |
23 | -> BlockAnd<Lvalue<'tcx>> |
24 | where M: Mirror<'tcx, Output=Expr<'tcx>> | |
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25 | { |
26 | let expr = self.hir.mirror(expr); | |
27 | self.expr_as_lvalue(block, expr) | |
28 | } | |
29 | ||
30 | fn expr_as_lvalue(&mut self, | |
31 | mut block: BasicBlock, | |
b039eaaf SL |
32 | expr: Expr<'tcx>) |
33 | -> BlockAnd<Lvalue<'tcx>> { | |
34 | debug!("expr_as_lvalue(block={:?}, expr={:?})", block, expr); | |
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35 | |
36 | let this = self; | |
37 | let expr_span = expr.span; | |
38 | match expr.kind { | |
39 | ExprKind::Scope { extent, value } => { | |
b039eaaf | 40 | this.in_scope(extent, block, |this| this.as_lvalue(block, value)) |
e9174d1e SL |
41 | } |
42 | ExprKind::Field { lhs, name } => { | |
43 | let lvalue = unpack!(block = this.as_lvalue(block, lhs)); | |
44 | let lvalue = lvalue.field(name); | |
45 | block.and(lvalue) | |
46 | } | |
47 | ExprKind::Deref { arg } => { | |
48 | let lvalue = unpack!(block = this.as_lvalue(block, arg)); | |
49 | let lvalue = lvalue.deref(); | |
50 | block.and(lvalue) | |
51 | } | |
52 | ExprKind::Index { lhs, index } => { | |
53 | let (usize_ty, bool_ty) = (this.hir.usize_ty(), this.hir.bool_ty()); | |
54 | ||
55 | let slice = unpack!(block = this.as_lvalue(block, lhs)); | |
56 | ||
57 | let idx = unpack!(block = this.as_operand(block, index)); | |
58 | ||
59 | // bounds check: | |
60 | let (len, lt) = (this.temp(usize_ty.clone()), this.temp(bool_ty)); | |
61 | this.cfg.push_assign(block, expr_span, // len = len(slice) | |
62 | &len, Rvalue::Len(slice.clone())); | |
63 | this.cfg.push_assign(block, expr_span, // lt = idx < len | |
64 | <, Rvalue::BinaryOp(BinOp::Lt, | |
65 | idx.clone(), | |
66 | Operand::Consume(len))); | |
67 | ||
b039eaaf | 68 | let (success, failure) = (this.cfg.start_new_block(), this.cfg.start_new_block()); |
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69 | this.cfg.terminate(block, |
70 | Terminator::If { | |
71 | cond: Operand::Consume(lt), | |
b039eaaf | 72 | targets: [success, failure], |
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73 | }); |
74 | this.panic(failure); | |
75 | success.and(slice.index(idx)) | |
76 | } | |
77 | ExprKind::SelfRef => { | |
78 | block.and(Lvalue::Arg(0)) | |
79 | } | |
80 | ExprKind::VarRef { id } => { | |
81 | let index = this.var_indices[&id]; | |
82 | block.and(Lvalue::Var(index)) | |
83 | } | |
84 | ExprKind::StaticRef { id } => { | |
85 | block.and(Lvalue::Static(id)) | |
86 | } | |
87 | ||
88 | ExprKind::Vec { .. } | | |
89 | ExprKind::Tuple { .. } | | |
90 | ExprKind::Adt { .. } | | |
91 | ExprKind::Closure { .. } | | |
92 | ExprKind::Unary { .. } | | |
93 | ExprKind::Binary { .. } | | |
94 | ExprKind::LogicalOp { .. } | | |
95 | ExprKind::Box { .. } | | |
96 | ExprKind::Cast { .. } | | |
97 | ExprKind::ReifyFnPointer { .. } | | |
98 | ExprKind::UnsafeFnPointer { .. } | | |
99 | ExprKind::Unsize { .. } | | |
100 | ExprKind::Repeat { .. } | | |
101 | ExprKind::Borrow { .. } | | |
102 | ExprKind::If { .. } | | |
103 | ExprKind::Match { .. } | | |
104 | ExprKind::Loop { .. } | | |
105 | ExprKind::Block { .. } | | |
106 | ExprKind::Assign { .. } | | |
107 | ExprKind::AssignOp { .. } | | |
108 | ExprKind::Break { .. } | | |
109 | ExprKind::Continue { .. } | | |
110 | ExprKind::Return { .. } | | |
111 | ExprKind::Literal { .. } | | |
112 | ExprKind::InlineAsm { .. } | | |
113 | ExprKind::Call { .. } => { | |
114 | // these are not lvalues, so we need to make a temporary. | |
115 | debug_assert!(match Category::of(&expr.kind) { | |
116 | Some(Category::Lvalue) => false, | |
117 | _ => true, | |
118 | }); | |
119 | this.as_temp(block, expr) | |
120 | } | |
121 | } | |
122 | } | |
123 | } |