Bug 1759206 - Part 1: Add module variant of JS::FinishIncrementalEncoding. r=nbp

Depends on D141742

Differential Revision: https://phabricator.services.mozilla.com/D141743

js/public/Transcoding.h

@@ -83,10 +83,24 @@ inline bool IsTranscodingBytecodeAligned(const void* offset) {
 
 // Finish incremental encoding started by one of:
 //   * JS::CompileAndStartIncrementalEncoding
-//   * JS::FinishOffThreadScriptAndStartIncrementalEncoding
+//   * JS::StartIncrementalEncoding
 //
-// The |script| argument of |FinishIncrementalEncoding| should be the top-level
-// script returned from one of the above.
+// For |JS::CompileAndStartIncrementalEncoding| case, the |script|
+// argument of |FinishIncrementalEncoding| must be the top-level script
+// returned from it.
+//
+// For |JS::StartIncrementalEncoding| case:
+//   * Regular script case
+//     the |script| argument must be the top-level script returned from
+//     |JS::InstantiateGlobalStencil| with the same stencil
+//   * Module script case
+//     the |script| argument must be the script returned by
+//     |JS::GetModuleScript| called on the module returned by
+//     |JS::InstantiateModuleStencil| with the same stencil
+//
+//     NOTE: |JS::GetModuleScript| doesn't work after evaluating the
+//           module script.  For the case, use Handle<JSObject*> variant of
+//           this function below.
 //
 // The |buffer| argument of |FinishIncrementalEncoding| is used for appending
 // the encoded bytecode into the buffer. If any of these functions failed, the
@@ -106,6 +120,15 @@ extern JS_PUBLIC_API bool FinishIncrementalEncoding(JSContext* cx,
                                                     Handle<JSScript*> script,
                                                     TranscodeBuffer& buffer);
 
+// Similar to |JS::FinishIncrementalEncoding|, but receives module obect.
+//
+// The |module| argument must be the module returned by
+// |JS::InstantiateModuleStencil| with the same stencil that's passed to
+// |JS::StartIncrementalEncoding|.
+extern JS_PUBLIC_API bool FinishIncrementalEncoding(JSContext* cx,
+                                                    Handle<JSObject*> module,
+                                                    TranscodeBuffer& buffer);
+
 // Check if the compile options and script's flag matches.
 //
 // JS::DecodeScript* and JS::DecodeOffThreadScript internally check this.

js/src/jsapi.cpp

@@ -4516,6 +4516,18 @@ JS_PUBLIC_API bool JS::FinishIncrementalEncoding(JSContext* cx,
   return true;
 }
 
+JS_PUBLIC_API bool JS::FinishIncrementalEncoding(JSContext* cx,
+                                                 JS::Handle<JSObject*> module,
+                                                 TranscodeBuffer& buffer) {
+  if (!module->as<ModuleObject>()
+           .scriptSourceObject()
+           ->source()
+           ->xdrFinalizeEncoder(cx, buffer)) {
+    return false;
+  }
+  return true;
+}
+
 bool JS::IsWasmModuleObject(HandleObject obj) {
   return obj->canUnwrapAs<WasmModuleObject>();
 }