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 rustc::middle::region::CodeExtent;
13 use rustc::middle::ty::Ty;
14 use rustc_data_structures::fnv::FnvHashMap;
18 use syntax::codemap::Span;
19 use tcx::{Cx, PatNode};
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 ast_block: &'tcx hir::Block)
85 let cfg = CFG { basic_blocks: vec![] };
87 // it's handy to have a temporary of type `()` sometimes, so make
88 // one from the start and keep it available
89 let temp_decls = vec![TempDecl::<'tcx> { ty: hir.unit_ty() }];
90 let unit_temp = Lvalue::Temp(0);
92 let mut builder = Builder {
95 extents: FnvHashMap(),
98 temp_decls: temp_decls,
100 var_indices: FnvHashMap(),
101 unit_temp: unit_temp,
104 assert_eq!(builder.cfg.start_new_block(), START_BLOCK);
105 assert_eq!(builder.cfg.start_new_block(), END_BLOCK);
106 assert_eq!(builder.cfg.start_new_block(), DIVERGE_BLOCK);
108 let mut block = START_BLOCK;
109 let arg_decls = unpack!(block = builder.args_and_body(block,
115 builder.cfg.terminate(block, Terminator::Goto { target: END_BLOCK });
116 builder.cfg.terminate(END_BLOCK, Terminator::Return);
119 basic_blocks: builder.cfg.basic_blocks,
120 extents: builder.extents,
121 var_decls: builder.var_decls,
122 arg_decls: arg_decls,
123 temp_decls: builder.temp_decls,
127 impl<'a,'tcx> Builder<'a,'tcx> {
128 fn args_and_body(&mut self,
129 mut block: BasicBlock,
130 implicit_arguments: Vec<Ty<'tcx>>,
131 explicit_arguments: Vec<(Ty<'tcx>, PatNode<'tcx>)>,
132 argument_extent: CodeExtent,
133 ast_block: &'tcx hir::Block)
134 -> BlockAnd<Vec<ArgDecl<'tcx>>>
136 self.in_scope(argument_extent, block, |this| {
138 let implicit_arg_decls = implicit_arguments.into_iter()
139 .map(|ty| ArgDecl { ty: ty });
141 // to start, translate the argument patterns and collect the
143 let explicit_arg_decls =
147 .map(|(index, (ty, pattern))| {
148 let lvalue = Lvalue::Arg(index as u32);
149 unpack!(block = this.lvalue_into_pattern(block,
151 hair::PatternRef::Hair(pattern),
156 implicit_arg_decls.chain(explicit_arg_decls).collect()
159 // start the first basic block and translate the body
160 unpack!(block = this.ast_block(&Lvalue::ReturnPointer, block, ast_block));
167 ///////////////////////////////////////////////////////////////////////////
168 // Builder methods are broken up into modules, depending on what kind
169 // of thing is being translated. Note that they use the `unpack` macro
170 // above extensively.