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::{FnOutput, Ty};
14 use rustc_data_structures::fnv::FnvHashMap;
18 use syntax::codemap::Span;
20 struct Builder<'a, 'tcx: 'a> {
23 scopes: Vec<scope::Scope<'tcx>>,
24 loop_scopes: Vec<scope::LoopScope>,
25 unit_temp: Lvalue<'tcx>,
26 var_decls: Vec<VarDecl<'tcx>>,
27 var_indices: FnvHashMap<ast::NodeId, u32>,
28 temp_decls: Vec<TempDecl<'tcx>>,
32 basic_blocks: Vec<BasicBlockData<'tcx>>,
35 ///////////////////////////////////////////////////////////////////////////
36 // The `BlockAnd` "monad" packages up the new basic block along with a
37 // produced value (sometimes just unit, of course). The `unpack!`
38 // macro (and methods below) makes working with `BlockAnd` much more
41 #[must_use] // if you don't use one of these results, you're leaving a dangling edge
42 struct BlockAnd<T>(BasicBlock, T);
45 fn and<T>(self, v: T) -> BlockAnd<T> {
49 fn unit(self) -> BlockAnd<()> {
54 /// Update a block pointer and return the value.
55 /// Use it like `let x = unpack!(block = self.foo(block, foo))`.
57 ($x:ident = $c:expr) => {
59 let BlockAnd(b, v) = $c;
67 let BlockAnd(b, ()) = $c;
73 ///////////////////////////////////////////////////////////////////////////
74 // construct() -- the main entry point for building MIR for a function
76 pub fn construct<'a,'tcx>(mut hir: Cx<'a,'tcx>,
78 implicit_arguments: Vec<Ty<'tcx>>,
79 explicit_arguments: Vec<(Ty<'tcx>, &'tcx hir::Pat)>,
80 argument_extent: CodeExtent,
81 return_ty: FnOutput<'tcx>,
82 ast_block: &'tcx hir::Block)
84 let cfg = CFG { basic_blocks: vec![] };
86 // it's handy to have a temporary of type `()` sometimes, so make
87 // one from the start and keep it available
88 let temp_decls = vec![TempDecl::<'tcx> { ty: hir.unit_ty() }];
89 let unit_temp = Lvalue::Temp(0);
91 let mut builder = Builder {
96 temp_decls: temp_decls,
98 var_indices: FnvHashMap(),
102 assert_eq!(builder.cfg.start_new_block(), START_BLOCK);
103 assert_eq!(builder.cfg.start_new_block(), END_BLOCK);
104 assert_eq!(builder.cfg.start_new_block(), DIVERGE_BLOCK);
106 let mut block = START_BLOCK;
107 let arg_decls = unpack!(block = builder.args_and_body(block,
113 builder.cfg.terminate(block, Terminator::Goto { target: END_BLOCK });
114 builder.cfg.terminate(END_BLOCK, Terminator::Return);
117 basic_blocks: builder.cfg.basic_blocks,
118 var_decls: builder.var_decls,
119 arg_decls: arg_decls,
120 temp_decls: builder.temp_decls,
121 return_ty: return_ty,
125 impl<'a,'tcx> Builder<'a,'tcx> {
126 fn args_and_body(&mut self,
127 mut block: BasicBlock,
128 implicit_arguments: Vec<Ty<'tcx>>,
129 explicit_arguments: Vec<(Ty<'tcx>, &'tcx hir::Pat)>,
130 argument_extent: CodeExtent,
131 ast_block: &'tcx hir::Block)
132 -> BlockAnd<Vec<ArgDecl<'tcx>>>
134 self.in_scope(argument_extent, block, |this| {
136 let implicit_arg_decls = implicit_arguments.into_iter()
137 .map(|ty| ArgDecl { ty: ty });
139 // to start, translate the argument patterns and collect the
141 let explicit_arg_decls =
145 .map(|(index, (ty, pattern))| {
146 let lvalue = Lvalue::Arg(index as u32);
147 let pattern = this.hir.irrefutable_pat(pattern);
148 unpack!(block = this.lvalue_into_pattern(block,
155 implicit_arg_decls.chain(explicit_arg_decls).collect()
158 // start the first basic block and translate the body
159 unpack!(block = this.ast_block(&Lvalue::ReturnPointer, block, ast_block));
166 ///////////////////////////////////////////////////////////////////////////
167 // Builder methods are broken up into modules, depending on what kind
168 // of thing is being translated. Note that they use the `unpack` macro
169 // above extensively.