xpcom/analysis/mayreturn.js@6474c204b198 (annotated)
xpcom/analysis/mayreturn.js
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 2 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 3 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 4 | |
| michael@0 | 5 | /* May-return analysis. |
| michael@0 | 6 | * This makes sense only for functions that return a value. The analysis |
| michael@0 | 7 | * determines the set of variables that may transitively reach the return |
| michael@0 | 8 | * statement. */ |
| michael@0 | 9 | |
| michael@0 | 10 | function MayReturnAnalysis() { |
| michael@0 | 11 | BackwardAnalysis.apply(this, arguments); |
| michael@0 | 12 | // May-return variables. We collect them all here. |
| michael@0 | 13 | this.vbls = create_decl_set(); |
| michael@0 | 14 | // The return value variable itself |
| michael@0 | 15 | this.retvar = undefined; |
| michael@0 | 16 | } |
| michael@0 | 17 | |
| michael@0 | 18 | MayReturnAnalysis.prototype = new BackwardAnalysis; |
| michael@0 | 19 | |
| michael@0 | 20 | MayReturnAnalysis.prototype.flowState = function(isn, state) { |
| michael@0 | 21 | if (TREE_CODE(isn) == GIMPLE_RETURN) { |
| michael@0 | 22 | let v = return_expr(isn); |
| michael@0 | 23 | if (!v) |
| michael@0 | 24 | return; |
| michael@0 | 25 | if (v.tree_code() == RESULT_DECL) // only an issue with 4.3 |
| michael@0 | 26 | throw new Error("Weird case hit"); |
| michael@0 | 27 | this.vbls.add(v); |
| michael@0 | 28 | state.add(v); |
| michael@0 | 29 | this.retvar = v; |
| michael@0 | 30 | } else if (TREE_CODE(isn) == GIMPLE_ASSIGN) { |
| michael@0 | 31 | let lhs = gimple_op(isn, 0); |
| michael@0 | 32 | let rhs = gimple_op(isn, 1); |
| michael@0 | 33 | if (DECL_P(rhs) && DECL_P(lhs) && state.has(lhs)) { |
| michael@0 | 34 | this.vbls.add(rhs); |
| michael@0 | 35 | state.add(rhs); |
| michael@0 | 36 | } |
| michael@0 | 37 | |
| michael@0 | 38 | for (let e in isn_defs(isn, 'strong')) { |
| michael@0 | 39 | if (DECL_P(e)) { |
| michael@0 | 40 | state.remove(e); |
| michael@0 | 41 | } |
| michael@0 | 42 | } |
| michael@0 | 43 | } |
| michael@0 | 44 | }; |
