1 // Copyright 2017 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.
11 // This is a small "shim" program which is used when wasm32 unit tests are run
12 // in this repository. This program is intended to be run in node.js and will
13 // load a wasm module into memory, instantiate it with a set of imports, and
16 // There's a bunch of helper functions defined here in `imports.env`, but note
17 // that most of them aren't actually needed to execute most programs. Many of
18 // these are just intended for completeness or debugging. Hopefully over time
19 // nothing here is needed for completeness.
21 const fs = require('fs');
22 const process = require('process');
23 const buffer = fs.readFileSync(process.argv[2]);
25 Error.stackTraceLimit = 20;
27 let m = new WebAssembly.Module(buffer);
31 function viewstruct(data, fields) {
32 return new Uint32Array(memory.buffer).subarray(data/4, data/4 + fields);
35 function copystr(a, b) {
36 let view = new Uint8Array(memory.buffer).subarray(a, a + b);
37 return String.fromCharCode.apply(null, view);
40 function syscall_write([fd, ptr, len]) {
41 let s = copystr(ptr, len);
43 case 1: process.stdout.write(s); break;
44 case 2: process.stderr.write(s); break;
48 function syscall_exit([code]) {
52 function syscall_args(params) {
53 let [ptr, len] = params;
55 // Calculate total required buffer size
57 for (let i = 2; i < process.argv.length; ++i) {
58 totalLen += Buffer.byteLength(process.argv[i]) + 1;
60 if (totalLen < 0) { totalLen = 0; }
63 // If buffer is large enough, copy data
64 if (len >= totalLen) {
65 let view = new Uint8Array(memory.buffer);
66 for (let i = 2; i < process.argv.length; ++i) {
67 let value = process.argv[i];
68 Buffer.from(value).copy(view, ptr);
69 ptr += Buffer.byteLength(process.argv[i]) + 1;
74 function syscall_getenv(params) {
75 let [keyPtr, keyLen, valuePtr, valueLen] = params;
77 let key = copystr(keyPtr, keyLen);
78 let value = process.env[key];
81 params[4] = 0xFFFFFFFF;
83 let view = new Uint8Array(memory.buffer);
84 let totalLen = Buffer.byteLength(value);
86 if (valueLen >= totalLen) {
87 Buffer.from(value).copy(view, valuePtr);
92 function syscall_time(params) {
94 let secs = Math.floor(t / 1000);
95 let millis = t % 1000;
96 params[1] = Math.floor(secs / 0x100000000);
97 params[2] = secs % 0x100000000;
98 params[3] = Math.floor(millis * 1000000);
103 // These are generated by LLVM itself for various intrinsic calls. Hopefully
104 // one day this is not necessary and something will automatically do this.
105 fmod: function(x, y) { return x % y; },
106 exp2: function(x) { return Math.pow(2, x); },
107 exp2f: function(x) { return Math.pow(2, x); },
108 ldexp: function(x, y) { return x * Math.pow(2, y); },
109 ldexpf: function(x, y) { return x * Math.pow(2, y); },
119 rust_wasm_syscall: function(index, data) {
121 case 1: syscall_write(viewstruct(data, 3)); return true;
122 case 2: syscall_exit(viewstruct(data, 1)); return true;
123 case 3: syscall_args(viewstruct(data, 3)); return true;
124 case 4: syscall_getenv(viewstruct(data, 5)); return true;
125 case 6: syscall_time(viewstruct(data, 4)); return true;
127 console.log("Unsupported syscall: " + index);
133 let instance = new WebAssembly.Instance(m, imports);
134 memory = instance.exports.memory;
136 instance.exports.main();