我可以獲取簡單的asm.js代碼嗎？ 使用emscripten編譯簡單的c api代碼時

Question

首先，檢查我的知識

1. C / C ++代碼>>編譯（emscripten [emcc]）>> asm.js代碼
   我可以將c / c ++代碼轉換為asm.js代碼，對嗎？

2. asm.js代碼>>編譯（binaryen [asm2wasm]）>> wasm代碼
   我可以將asm.js代碼轉換為wasm代碼，對嗎？

其次，我的主要問題是，如何獲得簡單的asm.js代碼？

我試圖按照步驟進行操作，但是我無法獲得簡單的asm.js代碼...使用emcc編譯時，我總是會得到復雜的asm.js代碼（多出5000行...）。

我的嘗試步驟

A.制作簡單的C api代碼// // my_add.c

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

B.將my_add.c代碼編譯為asm.js代碼（使用emcc）
我正在嘗試許多emcc選項...

emcc my_add.c

emcc my_add.c -s WASM = 1

等等...

我期望的...簡單的asm.js代碼（類似於遵循代碼...）

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

但是符合emcc的結果是復雜的asm.js代碼

  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 (eg case 4 above). We also need to check if Module 11 // already exists (eg 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 ++代碼是5〜6行..但是編譯的asm.js代碼是5000〜10000行...
我只想在編譯結果中使用簡單的'asm.js'代碼...
可能嗎？
而且...我該怎么做？

Answer 1

我找到了解決方案！

使用ONLY_MY_CODE和--separate-asm選項，

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

創建了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頻道 #emscripten
“ pdox”回答我。

pdox：emcc -O2-分析

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

emcc -O2-分析

命令執行簡單的功能..但是..但是它仍然會產生很長的代碼。（3000行...）（比較結果文件'a.out.js'是3000行....）