Issue 5131 - [emscripten] Clean separation of bindings code and runtime code

compile

Index: compile
===================================================================
--- a/compile
+++ b/compile
@@ -17,22 +17,16 @@
 
 import argparse
 import os
 import subprocess
 import sys
 
 BASE_DIR = os.path.dirname(__file__)
 SOURCE_DIR = os.path.join(BASE_DIR, 'compiled')
-SOURCE_FILES = [
-    os.path.join(path, f)
-    for (path, dirs, files) in os.walk(SOURCE_DIR)
-    for f in files
-    if f.endswith('.cpp')
-]
 BINDINGS_GENERATOR = os.path.join(SOURCE_DIR, 'bindings.cpp.js')
 BINDINGS_OUTPUT = os.path.join(SOURCE_DIR, 'bindings.js')
 COMPILER_OUTPUT = os.path.join(BASE_DIR, 'lib', 'compiled.js')
 GENERATION_PARAMS = {
     'SHELL_FILE': "'{}'".format(os.path.abspath(os.path.join(SOURCE_DIR,
                                                              'shell.js'))),
     'ASM_JS': 2,  # "almost asm"
     'TOTAL_MEMORY': 16*1024*1024,
@@ -45,16 +39,29 @@ GENERATION_PARAMS = {
     'TEXTDECODER': 0,
     'EXPORTED_RUNTIME_METHODS': ['cwrap', 'ccall', 'stringToAscii'],
 }
 DEFINES = []
 ADDITIONAL_PARAMS = ['-O3', '-m32', '-std=gnu++14', '--memory-init-file', '0',
                      '--emit-symbol-map']
 
 
+def get_source_files(phase):
+    for (path, dirs, files) in os.walk(SOURCE_DIR):
+        for f in files:
+            if os.path.splitext(f)[1] != '.cpp':
+                continue
+            if (
+                phase != 'bindings' and
+                os.path.basename(path) == 'bindings' and
+                not f.startswith('runtime_')
+            ):
+                continue
+            yield os.path.join(path, f)
+
 def getenv(emscripten_config):
     scope = {}
     execfile(emscripten_config, scope, scope)
     env = os.environ.copy()
     env.update({
         'EM_CONFIG': emscripten_config,
         'EMSCRIPTEN': scope['EMSCRIPTEN_ROOT'],
         'PYTHON': scope.get('PYTHON', sys.executable),
@@ -62,33 +69,33 @@ def getenv(emscripten_config):
     })
     return env
 
 
 def generate_bindings(env):
     params = [
         env['PYTHON'], os.path.join(env['EMSCRIPTEN'], 'emcc'),
         '-o', BINDINGS_GENERATOR, '-std=gnu++14', '-DPRINT_BINDINGS',
-    ] + SOURCE_FILES
+    ] + list(get_source_files('bindings'))
     subprocess.check_call(params, env=env)
 
     with open(BINDINGS_OUTPUT, 'w') as file:
         subprocess.check_call([env['NODE_JS'], BINDINGS_GENERATOR],
                               stdout=file)
 
 
 def run_compiler(env, debug=False, tracing=False):
     params = [
         env['PYTHON'], os.path.join(env['EMSCRIPTEN'], 'emcc'),
         '-o', COMPILER_OUTPUT,
         '--post-js', BINDINGS_OUTPUT,
     ]
     # Order matters. We sort source files so that we always get the same
     # results for the same source code.
-    params.extend(sorted(SOURCE_FILES))
+    params.extend(sorted(get_source_files('compile')))
     params.extend('-D' + flag for flag in DEFINES)
     for key, value in GENERATION_PARAMS.iteritems():
         params.extend(['-s', '{}={}'.format(key, str(value))])
     if debug:
         params.append('-g3')
     if tracing:
         params.append('--tracing')
     params.extend(ADDITIONAL_PARAMS)