Revert "Move all js library decisions to a single location (emscripte…

…n-core#8428)"

This reverts commit fb9b1dd.

emcc.py

@@ -981,7 +981,7 @@ def get_last_setting_change(setting):
     if error_on_missing_libraries_cmdline:
       shared.Settings.ERROR_ON_MISSING_LIBRARIES = int(error_on_missing_libraries_cmdline[len('ERROR_ON_MISSING_LIBRARIES='):])
 
-    settings_changes.append(process_libraries(libs, lib_dirs, input_files))
+    settings_changes.append(process_libraries(libs, lib_dirs, settings_changes, input_files))
 
     # If not compiling to JS, then we are compiling to an intermediate bitcode objects or library, so
     # ignore dynamic linking, since multiple dynamic linkings can interfere with each other
@@ -3138,7 +3138,7 @@ def worker_js_script(proxy_worker_filename):
   return web_gl_client_src + '\n' + proxy_client_src
 
 
-def process_libraries(libs, lib_dirs, input_files):
+def process_libraries(libs, lib_dirs, settings_changes, input_files):
   libraries = []
 
   # Find library files
@@ -3162,6 +3162,8 @@ def process_libraries(libs, lib_dirs, input_files):
     if not found:
       libraries += shared.Building.path_to_system_js_libraries(lib)
 
+  # Certain linker flags imply some link libraries to be pulled in by default.
+  libraries += shared.Building.path_to_system_js_libraries_for_settings(settings_changes)
   return 'SYSTEM_JS_LIBRARIES="' + ','.join(libraries) + '"'
 
 

src/modules.js

@@ -83,6 +83,9 @@ var LibraryManager = {
 
       // Additional filesystem libraries (in strict mode, link to these explicitly via -lxxx.js)
       if (!STRICT && !MINIMAL_RUNTIME) {
+        libraries = libraries.concat([
+          'library_lz4.js',
+        ]);
         if (ENVIRONMENT_MAY_BE_WEB || ENVIRONMENT_MAY_BE_WORKER) {
           libraries = libraries.concat([
             'library_idbfs.js',
@@ -118,27 +121,13 @@ var LibraryManager = {
         'library_idbstore.js',
         'library_async.js'
       ]);
-    } else {
-      if (EMTERPRETIFY_ASYNC || ASYNCIFY) {
-        libraries.push('library_async.js');
-      }
-      if (USE_SDL == 1) {
-        libraries.push('library_sdl.js');
-      }
-      if (USE_SDL == 2) {
-        libraries.push('library_egl.js', 'library_webgl.js');
-      }
     }
 
     // If there are any explicitly specified system JS libraries to link to, add those to link.
     if (SYSTEM_JS_LIBRARIES) {
       libraries = libraries.concat(SYSTEM_JS_LIBRARIES.split(','));
     }
 
-    if (LZ4) {
-      libraries.push('library_lz4.js');
-    }
-
     if (USE_WEBGL2) {
       libraries.push('library_webgl2.js');
     }
@@ -155,8 +144,6 @@ var LibraryManager = {
       LibraryManager.library = {};
     }
 
-    // TODO: deduplicate libraries (not needed for correctness, but avoids unnecessary work)
-
     // Save the list for has() queries later.
     this.libraries = libraries;
 

tools/shared.py

@@ -2664,6 +2664,25 @@ def path_to_system_js_libraries(library_name):
 
     return library_files
 
+  @staticmethod
+  # Given a list of Emscripten link settings, returns a list of paths to system JS libraries
+  # that should get linked automatically in to the build when those link settings are present.
+  def path_to_system_js_libraries_for_settings(link_settings):
+    system_js_libraries = []
+    if 'EMTERPRETIFY_ASYNC=1' in link_settings:
+      system_js_libraries += ['library_async.js']
+    if 'ASYNCIFY=1' in link_settings:
+      system_js_libraries += ['library_async.js']
+    if 'LZ4=1' in link_settings:
+      system_js_libraries += ['library_lz4.js']
+    if 'USE_SDL=1' in link_settings:
+      system_js_libraries += ['library_sdl.js']
+    if 'USE_SDL=2' in link_settings:
+      system_js_libraries += ['library_egl.js', 'library_webgl.js']
+    if 'USE_WEBGL2=1' in link_settings:
+      system_js_libraries += ['library_webgl2.js']
+    return [path_from_root('src', x) for x in system_js_libraries]
+
   @staticmethod
   def get_binaryen_feature_flags():
     # start with the MVP features, add the rest as needed