[C API] Add APIs for getting/setting function types, and a CallRef example (#6721)

Fixes #6718

Author: kripken

src/binaryen-c.cpp

@@ -5684,6 +5684,12 @@ void BinaryenFunctionSetBody(BinaryenFunctionRef func,
   assert(body);
   ((Function*)func)->body = (Expression*)body;
 }
+BinaryenHeapType BinaryenFunctionGetType(BinaryenFunctionRef func) {
+  return ((Function*)func)->type.getID();
+}
+void BinaryenFunctionSetType(BinaryenFunctionRef func, BinaryenHeapType type) {
+  ((Function*)func)->type = HeapType(type);
+}
 void BinaryenFunctionOptimize(BinaryenFunctionRef func,
                               BinaryenModuleRef module) {
   PassRunner passRunner((Module*)module);

src/binaryen-c.h

@@ -3136,6 +3136,11 @@ BinaryenFunctionGetBody(BinaryenFunctionRef func);
 // Sets the body of the specified `Function`.
 BINARYEN_API void BinaryenFunctionSetBody(BinaryenFunctionRef func,
                                           BinaryenExpressionRef body);
+// Gets the type of the specified `Function`.
+BINARYEN_API BinaryenHeapType BinaryenFunctionGetType(BinaryenFunctionRef func);
+// Sets the type of the specified `Function`.
+BINARYEN_API void BinaryenFunctionSetType(BinaryenFunctionRef func,
+                                          BinaryenHeapType type);
 
 // Runs the standard optimization passes on the function. Uses the currently set
 // global optimize and shrink level.

test/example/c-api-kitchen-sink.c

@@ -2194,6 +2194,42 @@ void test_typebuilder() {
   BinaryenModuleDispose(module);
 }
 
+void test_callref_and_types() {
+  BinaryenModuleRef module = BinaryenModuleCreate();
+  BinaryenModuleSetFeatures(module, BinaryenFeatureAll());
+
+  // Create a tiny function.
+  BinaryenFunctionRef tiny = BinaryenAddFunction(module,
+                                                 "tiny",
+                                                 BinaryenTypeNone(),
+                                                 BinaryenTypeNone(),
+                                                 NULL,
+                                                 0,
+                                                 BinaryenNop(module));
+
+  // Get a non-nullable type with that function's heap type.
+  BinaryenHeapType funcType =
+    BinaryenTypeFromHeapType(BinaryenFunctionGetType(tiny), false);
+
+  // Add a CallRef with that function and that type. Note that the RefFunc must
+  // use that type (and not generic funcref, as in the IR the type must always
+  // be precise).
+  BinaryenExpressionRef callRef =
+    BinaryenCallRef(module,
+                    BinaryenRefFunc(module, "tiny", funcType),
+                    NULL,
+                    0,
+                    BinaryenTypeNone(),
+                    false);
+  BinaryenFunctionSetBody(tiny, callRef);
+
+  bool didValidate = BinaryenModuleValidate(module);
+  assert(didValidate);
+  printf("module with a call_ref:\n");
+  BinaryenModulePrint(module);
+  BinaryenModuleDispose(module);
+}
+
 int main() {
   test_types();
   test_features();
@@ -2207,6 +2243,7 @@ int main() {
   test_for_each();
   test_func_opt();
   test_typebuilder();
+  test_callref_and_types();
 
   return 0;
 }

test/example/c-api-kitchen-sink.txt

@@ -3053,3 +3053,13 @@ module with recursive GC types:
   (unreachable)
  )
 )
+module with a call_ref:
+(module
+ (type $0 (func))
+ (elem declare func $tiny)
+ (func $tiny (type $0)
+  (call_ref $0
+   (ref.func $tiny)
+  )
+ )
+)