Expose ExpressionAnalyzer in C-/JS-API (#2585)

Instead of reinventing the wheel on our side, this adds ExpressionAnalyzer
bindings to the C- and JS-APIs, which can be useful for generators. For
example, a generator may decide to simplify a compilation step if a
subexpression doesn't have any side effects, or simply skip emitting
something that is likely to compile to a drop or an empty block right away.

1 files changed, 23 insertions, 0 deletions

diff --git a/src/js/binaryen.js-post.js b/src/js/binaryen.js-post.js
index 2993573d1..54f21ed07 100644
--- a/src/js/binaryen.js-post.js
+++ b/src/js/binaryen.js-post.js
@@ -457,6 +457,24 @@ function initializeConstants() {
   ].forEach(function(name) {
     Module['Operations'][name] = Module[name] = Module['_Binaryen' + name]();
   });
+
+  // Expression side effects
+  Module['SideEffects'] = {};
+  [ 'None',
+    'Branches',
+    'Calls',
+    'ReadsLocal',
+    'WritesLocal',
+    'ReadsGlobal',
+    'WritesGlobal',
+    'ReadsMemory',
+    'WritesMemory',
+    'ImplicitTrap',
+    'IsAtomic',
+    'Any'
+  ].forEach(function(name) {
+    Module['SideEffects'][name] = Module['_BinaryenSideEffect' + name]();
+  });
 }
 
 // 'Module' interface
@@ -2739,6 +2757,11 @@ Module['getExpressionInfo'] = function(expr) {
   }
 };
 
+// Gets the side effects of the specified expression
+Module['getSideEffects'] = function(expr) {
+  return Module['_BinaryenExpressionGetSideEffects'](expr);
+};
+
 Module['createType'] = function(types) {
   return preserveStack(function() {
     var array = i32sToStack(types);