--- a/js/src/builtin/Boolean.h
+++ b/js/src/builtin/Boolean.h
@@ -1,23 +1,23 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  * vim: set ts=8 sts=2 et sw=2 tw=80:
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+/* JS boolean interface. */
+
 #ifndef builtin_Boolean_h
 #define builtin_Boolean_h
 
-/*
- * JS boolean interface.
- */
+#include "jstypes.h"  // JS_PUBLIC_API
 
-struct JSContext;
-class JSString;
+struct JS_PUBLIC_API JSContext;
+class JS_PUBLIC_API JSString;
 
 namespace js {
 
 extern JSString* BooleanToString(JSContext* cx, bool b);
 
 }  // namespace js
 
 #endif /* builtin_Boolean_h */

--- a/js/src/builtin/intl/LanguageTag.h
+++ b/js/src/builtin/intl/LanguageTag.h
@@ -23,20 +23,20 @@
 
 #include "js/AllocPolicy.h"
 #include "js/GCAPI.h"
 #include "js/Result.h"
 #include "js/RootingAPI.h"
 #include "js/Utility.h"
 #include "js/Vector.h"
 
-struct JSContext;
+struct JS_PUBLIC_API JSContext;
 class JSLinearString;
-class JSString;
-class JSTracer;
+class JS_PUBLIC_API JSString;
+class JS_PUBLIC_API JSTracer;
 
 namespace js {
 
 namespace intl {
 
 /**
  * Return true if |language| is a valid language subtag.
  */

--- a/js/src/builtin/streams/WritableStream-inl.h
+++ b/js/src/builtin/streams/WritableStream-inl.h
@@ -9,24 +9,26 @@
 #ifndef builtin_streams_WritableStream_inl_h
 #define builtin_streams_WritableStream_inl_h
 
 #include "builtin/streams/WritableStream.h"
 
 #include "mozilla/Assertions.h"  // MOZ_ASSERT
 #include "mozilla/Attributes.h"  // MOZ_MUST_USE
 
+#include "jstypes.h"  // JS_PUBLIC_API
+
 #include "builtin/Promise.h"                              // js::PromiseObject
 #include "builtin/streams/WritableStreamDefaultWriter.h"  // js::WritableStreamDefaultWriter
 #include "js/RootingAPI.h"                                // JS::Handle
 #include "js/Value.h"                                     // JS::{,Object}Value
 
 #include "vm/Compartment-inl.h"  // js::UnwrapInternalSlot
 
-struct JSContext;
+struct JS_PUBLIC_API JSContext;
 
 namespace js {
 
 /**
  * Returns the writer associated with the given stream.
  *
  * Must only be called on WritableStreams that already have a writer
  * associated with them.

--- a/js/src/frontend/BinASTRuntimeSupport.h
+++ b/js/src/frontend/BinASTRuntimeSupport.h
@@ -20,17 +20,17 @@
 #include "js/AllocPolicy.h"  // SystemAllocPolicy
 #include "js/HashTable.h"    // HashMap, HashNumber
 #include "js/Result.h"       // JS::Result
 #include "js/TracingAPI.h"   // JSTracer
 #include "js/UniquePtr.h"    // UniquePtr
 #include "js/Vector.h"       // Vector
 
 class JSAtom;
-struct JSContext;
+struct JS_PUBLIC_API JSContext;
 
 namespace js {
 
 class ScriptSource;
 
 // Support for parsing JS Binary ASTs.
 struct BinaryASTSupport {
   using BinASTVariant = js::frontend::BinASTVariant;

--- a/js/src/jsapi-tests/testScriptSourceCompression.cpp
+++ b/js/src/jsapi-tests/testScriptSourceCompression.cpp
@@ -10,16 +10,17 @@
 #include "mozilla/Utf8.h"        // mozilla::Utf8Unit
 
 #include <algorithm>  // std::all_of, std::equal, std::move, std::transform
 #include <memory>     // std::uninitialized_fill_n
 #include <stddef.h>   // size_t
 #include <stdint.h>   // uint32_t
 
 #include "jsapi.h"  // JS_EnsureLinearString, JS_GC, JS_Get{Latin1,TwoByte}LinearStringChars, JS_GetStringLength, JS_ValueToFunction
+#include "jstypes.h"  // JS_PUBLIC_API
 
 #include "js/CompilationAndEvaluation.h"  // JS::Evaluate{,DontInflate}
 #include "js/CompileOptions.h"            // JS::CompileOptions
 #include "js/Conversions.h"               // JS::ToString
 #include "js/MemoryFunctions.h"           // JS_malloc
 #include "js/RootingAPI.h"                // JS::MutableHandle, JS::Rooted
 #include "js/SourceText.h"                // JS::SourceOwnership, JS::SourceText
 #include "js/UniquePtr.h"                 // js::UniquePtr
@@ -28,18 +29,18 @@
 #include "jsapi-tests/tests.h"
 #include "vm/Compression.h"  // js::Compressor::CHUNK_SIZE
 #include "vm/JSFunction.h"   // JSFunction::getOrCreateScript
 #include "vm/JSScript.h"  // JSScript, js::ScriptSource::MinimumCompressibleLength, js::SynchronouslyCompressSource
 
 using mozilla::ArrayLength;
 using mozilla::Utf8Unit;
 
-struct JSContext;
-class JSString;
+struct JS_PUBLIC_API JSContext;
+class JS_PUBLIC_API JSString;
 
 template <typename Unit>
 using Source = js::UniquePtr<Unit[], JS::FreePolicy>;
 
 constexpr size_t ChunkSize = js::Compressor::CHUNK_SIZE;
 constexpr size_t MinimumCompressibleLength =
     js::ScriptSource::MinimumCompressibleLength;
 

--- a/js/src/vm/JSContext.h
+++ b/js/src/vm/JSContext.h
@@ -6,32 +6,36 @@
 
 /* JS execution context. */
 
 #ifndef vm_JSContext_h
 #define vm_JSContext_h
 
 #include "mozilla/MemoryReporting.h"
 
+#include "jstypes.h"  // JS_PUBLIC_API
+
 #include "ds/TraceableFifo.h"
 #include "gc/Memory.h"
 #include "js/CharacterEncoding.h"
 #include "js/ContextOptions.h"  // JS::ContextOptions
 #include "js/GCVector.h"
 #include "js/Promise.h"
 #include "js/Result.h"
 #include "js/Utility.h"
 #include "js/Vector.h"
 #include "threading/ProtectedData.h"
 #include "util/StructuredSpewer.h"
 #include "vm/Activation.h"  // js::Activation
 #include "vm/ErrorReporting.h"
 #include "vm/MallocProvider.h"
 #include "vm/Runtime.h"
 
+struct JS_PUBLIC_API JSContext;
+
 struct DtoaState;
 
 namespace js {
 
 class AutoAllocInAtomsZone;
 class AutoMaybeLeaveAtomsZone;
 class AutoRealm;
 
@@ -142,18 +146,18 @@ enum class InterruptReason : uint32_t {
 };
 
 } /* namespace js */
 
 /*
  * A JSContext encapsulates the thread local state used when using the JS
  * runtime.
  */
-struct JSContext : public JS::RootingContext,
-                   public js::MallocProvider<JSContext> {
+struct JS_PUBLIC_API JSContext : public JS::RootingContext,
+                                 public js::MallocProvider<JSContext> {
   JSContext(JSRuntime* runtime, const JS::ContextOptions& options);
   ~JSContext();
 
   bool init(js::ContextKind kind);
 
  private:
   js::UnprotectedData<JSRuntime*> runtime_;
   js::WriteOnceData<js::ContextKind> kind_;