Add C/JS APIs to copy expressions (#2840)

This API enables use cases where we want to keep the original expression, yet utilize passes like `vacuum` or `precompute` to evaluate it without implicitly modifying the original.

C-API: **BinaryenExpressionCopy**(expr, module)
JS-API: **Module#copyExpression**(expr)

1 files changed, 3 insertions, 0 deletions

diff --git a/src/js/binaryen.js-post.js b/src/js/binaryen.js-post.js
index 75d6bf401..1706d2b97 100644
--- a/src/js/binaryen.js-post.js
+++ b/src/js/binaryen.js-post.js
@@ -2407,6 +2407,9 @@ function wrapModule(module, self) {
   self['setDebugLocation'] = function(func, expr, fileIndex, lineNumber, columnNumber) {
     return Module['_BinaryenFunctionSetDebugLocation'](func, expr, fileIndex, lineNumber, columnNumber);
   };
+  self['copyExpression'] = function(expr) {
+    return Module['_BinaryenExpressionCopy'](expr, module);
+  };
 
   return self;
 }