Question

首先，检查我的知识

c / c ++代码＆gt;＆gt;编译（emscripten [emcc]）＆gt;＆gt; asm.js代码
我可以获得asm.js代码的c / c ++代码，是不是？
asm.js code＆gt;＆gt;编译（binaryen [asm2wasm]）＆gt;＆gt; wasm代码
我可以将asm.js代码输入到代码中，是不是？

其次，我的主要问题是，如何获得简单的asm.js代码？

我试着按照步骤，但我不能简单的asm.js代码...... 当使用emcc编译时，我总是得到复杂的asm.js代码（5000行以上......）

我的尝试步骤

甲。制作简单的C api代码// my_add.c

#include <stdio.h>
#include <emscripten.h>

EMSCRIPTEN_KEEPALIVE
double my_add(double num1, double num2) {
    return num1 + num2;
}

B中。将my_add.c代码编译为asm.js代码（使用emcc）
我尝试了很多emcc选项...

emcc my_add.c

emcc my_add.c -s WASM = 1

等...

我的预期...简单的asm.js代码（类似于代码......）

function my_add(num1, num2) {
    "use asm";
    num1 = num1|0;
    num2 = num2|0;
    retrurn (num1 + num2)|0;
}

但emcc编译结果是复杂的asm.js代码

  1 // The Module object: Our interface to the outside world. We import
   2 // and export values on it, and do the work to get that through
   3 // closure compiler if necessary. There are various ways Module can be used:
   4 // 1. Not defined. We create it here
   5 // 2. A function parameter, function(Module) { ..generated code.. }
   6 // 3. pre-run appended it, var Module = {}; ..generated code..
   7 // 4. External script tag defines var Module.
   8 // We need to do an eval in order to handle the closure compiler
   9 // case, where this code here is minified but Module was defined
  10 // elsewhere (e.g. case 4 above). We also need to check if Module
  11 // already exists (e.g. case 3 above).
  12 // Note that if you want to run closure, and also to use Module
  13 // after the generated code, you will need to define   var Module = {};
  14 // before the code. Then that object will be used in the code, and you
  15 // can continue to use Module afterwards as well.
  16 var Module;
  17 if (!Module) Module = (typeof Module !== 'undefined' ? Module : null) || {};
  18 
  19 // Sometimes an existing Module object exists with properties
  20 // meant to overwrite the default module functionality. Here
  21 // we collect those properties and reapply _after_ we configure
  22 // the current environment's defaults to avoid having to be so
  23 // defensive during initialization.
  24 var moduleOverrides = {};
  25 for (var key in Module) {
  26   if (Module.hasOwnProperty(key)) {
  27     moduleOverrides[key] = Module[key];
  28   }
  29 }
  30 
  31 // The environment setup code below is customized to use Module.
  32 // *** Environment setup code ***
  33 var ENVIRONMENT_IS_WEB = false;
  34 var ENVIRONMENT_IS_WORKER = false;
  35 var ENVIRONMENT_IS_NODE = false;
  36 var ENVIRONMENT_IS_SHELL = false;
  37 

  ......
  
  
  2038 function _my_add($num1,$num2) {
2039  $num1 = +$num1;
2040  $num2 = +$num2;
2041  var $0 = 0.0, $1 = 0.0, $2 = 0.0, $3 = 0.0, $4 = 0.0, label = 0, sp = 0;
2042  sp = STACKTOP;
2043  STACKTOP = STACKTOP + 16|0; if ((STACKTOP|0) >= (STACK_MAX|0)) abort();
2044  $0 = $num1;
2045  $1 = $num2;
2046  $2 = $0;
2047  $3 = $1;
2048  $4 = $2 + $3;
2049  STACKTOP = sp;return (+$4);
2050 }

 .......

我的C / C ++代码是5~6行..但是编译asm.js代码是5000~10000行...
我只是想在编译结果中使用简单的'asm.js'代码...
有可能吗？
而且......我怎么能这样做？

Answer 1

我找到了解决方案！

使用ONLY_MY_CODE和--separate-asm选项，

emcc my_add.c -O2 -profiling -s ONLY_MY_CODE=1 -g2 --separate-asm -o abc.js

创建abc.asm.js文件：

Module["asm"] = (function(global, env, buffer) {
 "use asm";

 function _my_add(d1, d2) {
  d1 = +d1;
  d2 = +d2;
  return +(d1 + d2);
 }
 return {
  _my_add: _my_add
 };
});

Answer 2

IRC ch。 #emscripten
＆＃39; pdox＆＃39;回答我..

pdox：emcc -O2 -profiling

＆＃13;

3601 function _my_add(d1, d2) {
3602  d1 = +d1;
3603  d2 = +d2;
3604  return +(d1 + d2);
3605 }

＆＃13;

emcc -O2 -profiling

命令make simple function .. 但..但它仍然产生一个长代码。（3000线...）（complie结果文件＆＃39; a.out.js＆＃39;是3000行....）

我可以获得简单的asm.js代码吗？当简单的c api代码使用emscripten编译时

2 个答案: