1 // Copyright 2012-2014 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.
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.
12 use hair::cx::{Cx, PatNode};
13 use rustc::middle::region::CodeExtent;
14 use rustc::middle::ty::{FnOutput, Ty};
15 use rustc_data_structures::fnv::FnvHashMap;
19 use syntax::codemap::Span;
21 struct Builder<'a, 'tcx: 'a> {
23 extents: FnvHashMap<CodeExtent, Vec<GraphExtent>>,
25 scopes: Vec<scope::Scope<'tcx>>,
26 loop_scopes: Vec<scope::LoopScope>,
27 unit_temp: Lvalue<'tcx>,
28 var_decls: Vec<VarDecl<'tcx>>,
29 var_indices: FnvHashMap<ast::NodeId, u32>,
30 temp_decls: Vec<TempDecl<'tcx>>,
34 basic_blocks: Vec<BasicBlockData<'tcx>>,
37 ///////////////////////////////////////////////////////////////////////////
38 // The `BlockAnd` "monad" packages up the new basic block along with a
39 // produced value (sometimes just unit, of course). The `unpack!`
40 // macro (and methods below) makes working with `BlockAnd` much more
43 #[must_use] // if you don't use one of these results, you're leaving a dangling edge
44 struct BlockAnd<T>(BasicBlock, T);
47 fn and<T>(self, v: T) -> BlockAnd<T> {
51 fn unit(self) -> BlockAnd<()> {
56 /// Update a block pointer and return the value.
57 /// Use it like `let x = unpack!(block = self.foo(block, foo))`.
59 ($x:ident = $c:expr) => {
61 let BlockAnd(b, v) = $c;
69 let BlockAnd(b, ()) = $c;
75 ///////////////////////////////////////////////////////////////////////////
76 // construct() -- the main entry point for building MIR for a function
78 pub fn construct<'a,'tcx>(mut hir: Cx<'a,'tcx>,
80 implicit_arguments: Vec<Ty<'tcx>>,
81 explicit_arguments: Vec<(Ty<'tcx>, PatNode<'tcx>)>,
82 argument_extent: CodeExtent,
83 return_ty: FnOutput<'tcx>,
84 ast_block: &'tcx hir::Block)
86 let cfg = CFG { basic_blocks: vec![] };
88 // it's handy to have a temporary of type `()` sometimes, so make
89 // one from the start and keep it available
90 let temp_decls = vec![TempDecl::<'tcx> { ty: hir.unit_ty() }];
91 let unit_temp = Lvalue::Temp(0);
93 let mut builder = Builder {
96 extents: FnvHashMap(),
99 temp_decls: temp_decls,
101 var_indices: FnvHashMap(),
102 unit_temp: unit_temp,
105 assert_eq!(builder.cfg.start_new_block(), START_BLOCK);
106 assert_eq!(builder.cfg.start_new_block(), END_BLOCK);
107 assert_eq!(builder.cfg.start_new_block(), DIVERGE_BLOCK);
109 let mut block = START_BLOCK;
110 let arg_decls = unpack!(block = builder.args_and_body(block,
116 builder.cfg.terminate(block, Terminator::Goto { target: END_BLOCK });
117 builder.cfg.terminate(END_BLOCK, Terminator::Return);
120 basic_blocks: builder.cfg.basic_blocks,
121 extents: builder.extents,
122 var_decls: builder.var_decls,
123 arg_decls: arg_decls,
124 temp_decls: builder.temp_decls,
125 return_ty: return_ty,
129 impl<'a,'tcx> Builder<'a,'tcx> {
130 fn args_and_body(&mut self,
131 mut block: BasicBlock,
132 implicit_arguments: Vec<Ty<'tcx>>,
133 explicit_arguments: Vec<(Ty<'tcx>, PatNode<'tcx>)>,
134 argument_extent: CodeExtent,
135 ast_block: &'tcx hir::Block)
136 -> BlockAnd<Vec<ArgDecl<'tcx>>>
138 self.in_scope(argument_extent, block, |this| {
140 let implicit_arg_decls = implicit_arguments.into_iter()
141 .map(|ty| ArgDecl { ty: ty });
143 // to start, translate the argument patterns and collect the
145 let explicit_arg_decls =
149 .map(|(index, (ty, pattern))| {
150 let lvalue = Lvalue::Arg(index as u32);
151 unpack!(block = this.lvalue_into_pattern(block,
153 hair::PatternRef::Hair(pattern),
158 implicit_arg_decls.chain(explicit_arg_decls).collect()
161 // start the first basic block and translate the body
162 unpack!(block = this.ast_block(&Lvalue::ReturnPointer, block, ast_block));
169 ///////////////////////////////////////////////////////////////////////////
170 // Builder methods are broken up into modules, depending on what kind
171 // of thing is being translated. Note that they use the `unpack` macro
172 // above extensively.