Build embind/fetch/etc as system libraries rather than compile-on-demand during linking (#8817)

Author: sbc100

emcc.py

@@ -224,7 +224,6 @@ def __init__(self):
     self.shell_path = shared.path_from_root('src', 'shell.html')
     self.source_map_base = ''
     self.js_libraries = []
-    self.bind = False
     self.emrun = False
     self.cpu_profiler = False
     self.thread_profiler = False
@@ -1077,13 +1076,6 @@ def check(input_file):
     # Note the exports the user requested
     shared.Building.user_requested_exports = shared.Settings.EXPORTED_FUNCTIONS[:]
 
-    if options.bind:
-      shared.Settings.EMBIND = 1
-      # If we are using embind and generating JS, now is the time to link in bind.cpp
-      if final_suffix in JS_CONTAINING_ENDINGS:
-        input_files.append((next_arg_index, shared.path_from_root('system', 'lib', 'embind', 'bind.cpp')))
-        next_arg_index += 1
-
     # -s ASSERTIONS=1 implies the heaviest stack overflow check mode. Set the implication here explicitly to avoid having to
     # do preprocessor "#if defined(ASSERTIONS) || defined(STACK_OVERFLOW_CHECK)" in .js files, which is not supported.
     if shared.Settings.ASSERTIONS:
@@ -1183,8 +1175,10 @@ def check(input_file):
       # stb_image 2.x need to have STB_IMAGE_IMPLEMENTATION defined to include the implementation when compiling
       newargs.append('-DSTB_IMAGE_IMPLEMENTATION')
 
+    forced_stdlibs = []
+
     if shared.Settings.ASMFS and final_suffix in JS_CONTAINING_ENDINGS:
-      input_files.append((next_arg_index, shared.path_from_root('system', 'lib', 'fetch', 'asmfs.cpp')))
+      forced_stdlibs.append('libasmfs')
       newargs.append('-D__EMSCRIPTEN_ASMFS__=1')
       next_arg_index += 1
       shared.Settings.FILESYSTEM = 0
@@ -1193,16 +1187,18 @@ def check(input_file):
       options.js_libraries.append(shared.path_from_root('src', 'library_asmfs.js'))
 
     if shared.Settings.FETCH and final_suffix in JS_CONTAINING_ENDINGS:
-      input_files.append((next_arg_index, shared.path_from_root('system', 'lib', 'fetch', 'emscripten_fetch.cpp')))
+      forced_stdlibs.append('libfetch')
       next_arg_index += 1
       options.js_libraries.append(shared.path_from_root('src', 'library_fetch.js'))
       if shared.Settings.USE_PTHREADS:
         shared.Settings.FETCH_WORKER_FILE = unsuffixed(os.path.basename(target)) + '.fetch.js'
 
-    forced_stdlibs = []
     if shared.Settings.DEMANGLE_SUPPORT:
       shared.Settings.EXPORTED_FUNCTIONS += ['___cxa_demangle']
-      forced_stdlibs += ['libc++abi']
+      forced_stdlibs.append('libc++abi')
+
+    if shared.Settings.EMBIND:
+      forced_stdlibs.append('libembind')
 
     if not shared.Settings.ONLY_MY_CODE and not shared.Settings.MINIMAL_RUNTIME:
       # Always need malloc and free to be kept alive and exported, for internal use and other modules
@@ -2503,7 +2499,7 @@ def check_bad_eq(arg):
       shared.Settings.EMIT_SYMBOL_MAP = 1
       newargs[i] = ''
     elif newargs[i] == '--bind':
-      options.bind = True
+      shared.Settings.EMBIND = 1
       newargs[i] = ''
       options.js_libraries.append(shared.path_from_root('src', 'embind', 'emval.js'))
       options.js_libraries.append(shared.path_from_root('src', 'embind', 'embind.js'))

tools/system_libs.py

@@ -341,13 +341,13 @@ def get_ext(self):
     """
     Return the appropriate file extension for this library.
     """
-    return 'a' if shared.Settings.WASM_BACKEND and shared.Settings.WASM_OBJECT_FILES else 'bc'
+    return '.a' if shared.Settings.WASM_BACKEND and shared.Settings.WASM_OBJECT_FILES else '.bc'
 
   def get_name(self):
     """
     Return the full name of the library file, including the file extension.
     """
-    return self.get_base_name() + '.' + self.get_ext()
+    return self.get_base_name() + self.get_ext()
 
   def get_symbols(self):
     """
@@ -549,7 +549,7 @@ class NoBCLibrary(Library):
   # libraries, only the object files, and by extension, their contained global constructors, that are actually needed
   # will be linked in.
   def get_ext(self):
-    return 'a'
+    return '.a'
 
 
 class libcompiler_rt(Library):
@@ -907,6 +907,34 @@ def get_default_variation(cls, **kwargs):
     )
 
 
+class libembind(CXXLibrary):
+  name = 'libembind'
+  cflags = ['-std=c++11']
+  depends = ['libc++abi']
+  never_force = True
+
+  def get_files(self):
+    return [shared.path_from_root('system', 'lib', 'embind', 'bind.cpp')]
+
+
+class libfetch(CXXLibrary, MTLibrary):
+  name = 'libfetch'
+  depends = ['libc++abi']
+  never_force = True
+
+  def get_files(self):
+    return [shared.path_from_root('system', 'lib', 'fetch', 'emscripten_fetch.cpp')]
+
+
+class libasmfs(CXXLibrary, MTLibrary):
+  name = 'libasmfs'
+  depends = ['libc++abi']
+  never_force = True
+
+  def get_files(self):
+    return [shared.path_from_root('system', 'lib', 'fetch', 'asmfs.cpp')]
+
+
 class libhtml5(Library):
   name = 'libhtml5'
   symbols = read_symbols(shared.path_from_root('system', 'lib', 'html5.symbols'))
@@ -1162,12 +1190,14 @@ class Dummy(object):
   system_libs_map = Library.get_usable_variations()
   system_libs = sorted(system_libs_map.values(), key=lambda lib: lib.name)
 
-  # Setting this in the environment will avoid checking dependencies and make building big projects a little faster
-  # 1 means include everything; otherwise it can be the name of a lib (libc++, etc.)
-  # You can provide 1 to include everything, or a comma-separated list with the ones you want
+  # Setting this in the environment will avoid checking dependencies and make
+  # building big projects a little faster 1 means include everything; otherwise
+  # it can be the name of a lib (libc++, etc.).
+  # You can provide 1 to include everything, or a comma-separated list with the
+  # ones you want
   force = os.environ.get('EMCC_FORCE_STDLIBS')
   if force == '1':
-    force = ','.join(key for key, lib in system_libs_map.items() if not lib.never_force)
+    force = ','.join(name for name, lib in system_libs_map.items() if not lib.never_force)
   force_include = set((force.split(',') if force else []) + forced)
   if force_include:
     logger.debug('forcing stdlibs: ' + str(force_include))
@@ -1186,7 +1216,7 @@ def add_library(lib):
 
     logger.debug('including %s (%s)' % (lib.name, lib.get_name()))
 
-    need_whole_archive = lib.name in force_include and lib.get_ext() != 'bc'
+    need_whole_archive = lib.name in force_include and lib.get_ext() == '.a'
     libs_to_link.append((lib.get_path(), need_whole_archive))
 
     # Recursively add dependencies