Add const expression utilities to binaryen-c/.js (#1288)

3 files changed, 85 insertions, 0 deletions

diff --git a/src/binaryen-c.cpp b/src/binaryen-c.cpp
index 9883aef71..f4084eb82 100644
--- a/src/binaryen-c.cpp
+++ b/src/binaryen-c.cpp
@@ -797,6 +797,60 @@ void BinaryenExpressionPrint(BinaryenExpressionRef expr) {
   WasmPrinter::printExpression((Expression*)expr, std::cout);
   std::cout << '\n';
 }
+int32_t BinaryenConstGetValueI32(BinaryenExpressionRef expr) {
+  if (tracing) {
+    std::cout << "  BinaryenConstGetValueI32(expressions[" << expressions[expr] << "]);\n";
+  }
+
+  auto* expression = (Expression*)expr;
+  assert(expression->is<Const>());
+  return static_cast<Const*>(expression)->value.geti32();
+}
+int64_t BinaryenConstGetValueI64(BinaryenExpressionRef expr) {
+  if (tracing) {
+    std::cout << "  BinaryenConstGetValueI64(expressions[" << expressions[expr] << "]);\n";
+  }
+
+  auto* expression = (Expression*)expr;
+  assert(expression->is<Const>());
+  return static_cast<Const*>(expression)->value.geti64();
+}
+int32_t BinaryenConstGetValueI64Low(BinaryenExpressionRef expr) {
+  if (tracing) {
+    std::cout << "  BinaryenConstGetValueI64Low(expressions[" << expressions[expr] << "]);\n";
+  }
+
+  auto* expression = (Expression*)expr;
+  assert(expression->is<Const>());
+  return (int32_t)(static_cast<Const*>(expression)->value.geti64() & 0xffffffff);
+}
+int32_t BinaryenConstGetValueI64High(BinaryenExpressionRef expr) {
+  if (tracing) {
+    std::cout << "  BinaryenConstGetValueI64High(expressions[" << expressions[expr] << "]);\n";
+  }
+
+  auto* expression = (Expression*)expr;
+  assert(expression->is<Const>());
+  return (int32_t)(static_cast<Const*>(expression)->value.geti64() >> 32);
+}
+float BinaryenConstGetValueF32(BinaryenExpressionRef expr) {
+  if (tracing) {
+    std::cout << "  BinaryenConstGetValueF32(expressions[" << expressions[expr] << "]);\n";
+  }
+
+  auto* expression = (Expression*)expr;
+  assert(expression->is<Const>());
+  return static_cast<Const*>(expression)->value.getf32();
+}
+double BinaryenConstGetValueF64(BinaryenExpressionRef expr) {
+  if (tracing) {
+    std::cout << "  BinaryenConstGetValueF64(expressions[" << expressions[expr] << "]);\n";
+  }
+
+  auto* expression = (Expression*)expr;
+  assert(expression->is<Const>());
+  return static_cast<Const*>(expression)->value.getf64();
+}
 
 // Functions
 
diff --git a/src/binaryen-c.h b/src/binaryen-c.h
index c136b5f70..88fe8904c 100644
--- a/src/binaryen-c.h
+++ b/src/binaryen-c.h
@@ -371,6 +371,18 @@ BinaryenExpressionId BinaryenExpressionGetId(BinaryenExpressionRef expr);
 BinaryenType BinaryenExpressionGetType(BinaryenExpressionRef expr);
 // Print an expression to stdout. Useful for debugging.
 void BinaryenExpressionPrint(BinaryenExpressionRef expr);
+// Gets the 32-bit integer value of the specified `Const` expression.
+int32_t BinaryenConstGetValueI32(BinaryenExpressionRef expr);
+// Gets the 64-bit integer value of the specified `Const` expression.
+int64_t BinaryenConstGetValueI64(BinaryenExpressionRef expr);
+// Gets the low 32-bits of a 64-bit integer value of the specified `Const` expression. Useful where I64 returning exports are illegal, i.e. binaryen.js.
+int32_t BinaryenConstGetValueI64Low(BinaryenExpressionRef expr);
+// Gets the high 32-bits of a 64-bit integer value of the specified `Const` expression. Useful where I64 returning exports are illegal, i.e. binaryen.js.
+int32_t BinaryenConstGetValueI64High(BinaryenExpressionRef expr);
+// Gets the 32-bit float value of the specified `Const` expression.
+float BinaryenConstGetValueF32(BinaryenExpressionRef expr);
+// Gets the 64-bit float value of the specified `Const` expression.
+double BinaryenConstGetValueF64(BinaryenExpressionRef expr);
 
 // Functions
 
diff --git a/src/js/binaryen.js-post.js b/src/js/binaryen.js-post.js
index a29a035c6..352da1c0a 100644
--- a/src/js/binaryen.js-post.js
+++ b/src/js/binaryen.js-post.js
@@ -1111,6 +1111,25 @@
     return Module['_BinaryenExpressionGetType'](expr);
   };
 
+  Module['getConstValueI32'] = function(expr) {
+    return Module['_BinaryenConstGetValueI32'](expr);
+  };
+
+  Module['getConstValueI64'] = function(expr) {
+    return {
+      'low': Module['_BinaryenConstGetValueI64Low'](expr),
+      'high': Module['_BinaryenConstGetValueI64High'](expr)
+    };
+  };
+
+  Module['getConstValueF32'] = function(expr) {
+    return Module['_BinaryenConstGetValueF32'](expr);
+  };
+
+  Module['getConstValueF64'] = function(expr) {
+    return Module['_BinaryenConstGetValueF64'](expr);
+  };
+
   // emit text of an expression or a module
   Module['emitText'] = function(expr) {
     if (typeof expr === 'object') {