Don't EXPORT_ALL for linkable code (#7371)

This is a breaking change, in which we no longer set EXPORT_ALL in MAIN_MODULEs and SIDE_MODULEs. This makes our linking behavior more "standard", and is more future-proof for wasm backend linking.

Fixes #5586, fixes #7189. See more context there.

Author: kripken

ChangeLog.md

@@ -15,6 +15,13 @@ full changeset diff at the end of each section.
 
 Current Trunk
 -------------
+ - Breaking change: Do not automatically set EXPORT_ALL for MAIN_MODULES or
+   SIDE_MODULES. This means that you must explicitly export things that will
+   be called from outside (normally, on EXPORTED_FUNCTIONS), or
+   you can manually enable EXPORT_ALL yourself (which returns to the exact
+   same behavior as before). This change brings us in line with more standard
+   dynamic linking, and will match what the LLVM wasm backend will have.
+   See #7312.
 
 v1.38.14: 10/22/2018
 --------------------

emcc.py

@@ -1164,7 +1164,6 @@ def check(input_file):
         if shared.Settings.EMULATED_FUNCTION_POINTERS == 0:
           shared.Settings.EMULATED_FUNCTION_POINTERS = 2 # by default, use optimized function pointer emulation
         shared.Settings.ERROR_ON_UNDEFINED_SYMBOLS = shared.Settings.WARN_ON_UNDEFINED_SYMBOLS = 0
-        shared.Settings.EXPORT_ALL = 1
 
       if shared.Settings.EMTERPRETIFY:
         shared.Settings.FINALIZE_ASM_JS = 0

tests/test_browser.py

@@ -2126,8 +2126,8 @@ def test_runtimelink(self):
       print(wasm)
       main, supp = self.setup_runtimelink_test()
       open('supp.cpp', 'w').write(supp)
-      run_process([PYTHON, EMCC, 'supp.cpp', '-o', 'supp.' + ('wasm' if wasm else 'js'), '-s', 'SIDE_MODULE=1', '-O2', '-s', 'WASM=%d' % wasm])
-      self.btest(main, args=['-DBROWSER=1', '-s', 'MAIN_MODULE=1', '-O2', '-s', 'WASM=%d' % wasm, '-s', 'RUNTIME_LINKED_LIBS=["supp.' + ('wasm' if wasm else 'js') + '"]'], expected='76')
+      run_process([PYTHON, EMCC, 'supp.cpp', '-o', 'supp.' + ('wasm' if wasm else 'js'), '-s', 'SIDE_MODULE=1', '-O2', '-s', 'WASM=%d' % wasm, '-s', 'EXPORT_ALL=1'])
+      self.btest(main, args=['-DBROWSER=1', '-s', 'MAIN_MODULE=1', '-O2', '-s', 'WASM=%d' % wasm, '-s', 'RUNTIME_LINKED_LIBS=["supp.' + ('wasm' if wasm else 'js') + '"]', '-s', 'EXPORT_ALL=1'], expected='76')
 
   def test_pre_run_deps(self):
     # Adding a dependency in preRun will delay run
@@ -2319,7 +2319,7 @@ def test_emscripten_async_wget2(self):
   @unittest.skip('non-fastcomp is deprecated and fails in 3.5')
   def test_module(self):
     run_process([PYTHON, EMCC, path_from_root('tests', 'browser_module.cpp'), '-o', 'module.js', '-O2', '-s', 'SIDE_MODULE=1', '-s', 'DLOPEN_SUPPORT=1', '-s', 'EXPORTED_FUNCTIONS=["_one", "_two"]'])
-    self.btest('browser_main.cpp', args=['-O2', '-s', 'MAIN_MODULE=1', '-s', 'DLOPEN_SUPPORT=1'], expected='8')
+    self.btest('browser_main.cpp', args=['-O2', '-s', 'MAIN_MODULE=1', '-s', 'DLOPEN_SUPPORT=1', '-s', 'EXPORT_ALL=1'], expected='8')
 
   def test_preload_module(self):
     open('library.c', 'w').write(r'''
@@ -2328,7 +2328,7 @@ def test_preload_module(self):
         return 42;
       }
     ''')
-    run_process([PYTHON, EMCC, 'library.c', '-s', 'SIDE_MODULE=1', '-O2', '-o', 'library.wasm', '-s', 'WASM=1'])
+    run_process([PYTHON, EMCC, 'library.c', '-s', 'SIDE_MODULE=1', '-O2', '-o', 'library.wasm', '-s', 'WASM=1', '-s', 'EXPORT_ALL=1'])
     os.rename('library.wasm', 'library.so')
     main = r'''
       #include <dlfcn.h>
@@ -2359,7 +2359,7 @@ def test_preload_module(self):
     '''
     self.btest(
       main,
-      args=['-s', 'MAIN_MODULE=1', '--preload-file', '.@/', '-O2', '-s', 'WASM=1', '--use-preload-plugins'],
+      args=['-s', 'MAIN_MODULE=1', '--preload-file', '.@/', '-O2', '-s', 'WASM=1', '--use-preload-plugins', '-s', 'EXPORT_ALL=1'],
       expected='0')
 
   def test_mmap_file(self):
@@ -3277,24 +3277,24 @@ def test_dynamic_link(self):
         return ret;
       }
     ''')
-    run_process([PYTHON, EMCC, 'side.cpp', '-s', 'SIDE_MODULE=1', '-O2', '-o', 'side.wasm'])
-    self.btest(self.in_dir('main.cpp'), '2', args=['-s', 'MAIN_MODULE=1', '-O2', '--pre-js', 'pre.js'])
+    run_process([PYTHON, EMCC, 'side.cpp', '-s', 'SIDE_MODULE=1', '-O2', '-o', 'side.wasm', '-s', 'EXPORT_ALL=1'])
+    self.btest(self.in_dir('main.cpp'), '2', args=['-s', 'MAIN_MODULE=1', '-O2', '--pre-js', 'pre.js', '-s', 'EXPORT_ALL=1'])
 
     print('wasm in worker (we can read binary data synchronously there)')
 
     open('pre.js', 'w').write('''
       var Module = { dynamicLibraries: ['side.wasm'] };
   ''')
-    run_process([PYTHON, EMCC, 'side.cpp', '-s', 'SIDE_MODULE=1', '-O2', '-o', 'side.wasm', '-s', 'WASM=1'])
-    self.btest(self.in_dir('main.cpp'), '2', args=['-s', 'MAIN_MODULE=1', '-O2', '--pre-js', 'pre.js', '-s', 'WASM=1', '--proxy-to-worker'])
+    run_process([PYTHON, EMCC, 'side.cpp', '-s', 'SIDE_MODULE=1', '-O2', '-o', 'side.wasm', '-s', 'WASM=1', '-s', 'EXPORT_ALL=1'])
+    self.btest(self.in_dir('main.cpp'), '2', args=['-s', 'MAIN_MODULE=1', '-O2', '--pre-js', 'pre.js', '-s', 'WASM=1', '--proxy-to-worker', '-s', 'EXPORT_ALL=1'])
 
     print('wasm (will auto-preload since no sync binary reading)')
 
     open('pre.js', 'w').write('''
       Module.dynamicLibraries = ['side.wasm'];
   ''')
     # same wasm side module works
-    self.btest(self.in_dir('main.cpp'), '2', args=['-s', 'MAIN_MODULE=1', '-O2', '--pre-js', 'pre.js', '-s', 'WASM=1'])
+    self.btest(self.in_dir('main.cpp'), '2', args=['-s', 'MAIN_MODULE=1', '-O2', '--pre-js', 'pre.js', '-s', 'WASM=1', '-s', 'EXPORT_ALL=1'])
 
   @requires_graphics_hardware
   @requires_sync_compilation
@@ -3324,9 +3324,9 @@ def test_dynamic_link_glemu(self):
         return (const char *)glGetString(GL_EXTENSIONS);
       }
     ''')
-    run_process([PYTHON, EMCC, 'side.cpp', '-s', 'SIDE_MODULE=1', '-O2', '-o', 'side.wasm', '-lSDL'])
+    run_process([PYTHON, EMCC, 'side.cpp', '-s', 'SIDE_MODULE=1', '-O2', '-o', 'side.wasm', '-lSDL', '-s', 'EXPORT_ALL=1'])
 
-    self.btest(self.in_dir('main.cpp'), '1', args=['-s', 'MAIN_MODULE=1', '-O2', '-s', 'LEGACY_GL_EMULATION=1', '-lSDL', '-lGL', '--pre-js', 'pre.js'])
+    self.btest(self.in_dir('main.cpp'), '1', args=['-s', 'MAIN_MODULE=1', '-O2', '-s', 'LEGACY_GL_EMULATION=1', '-lSDL', '-lGL', '--pre-js', 'pre.js', '-s', 'EXPORT_ALL=1'])
 
   def test_memory_growth_during_startup(self):
     open('data.dat', 'w').write('X' * (30 * 1024 * 1024))

tests/test_core.py

@@ -2426,10 +2426,12 @@ def test_runtimelink(self):
   def prep_dlfcn_lib(self):
     self.set_setting('MAIN_MODULE', 0)
     self.set_setting('SIDE_MODULE', 1)
+    self.set_setting('EXPORT_ALL', 1)
 
   def prep_dlfcn_main(self):
     self.set_setting('MAIN_MODULE', 1)
     self.set_setting('SIDE_MODULE', 0)
+    self.set_setting('EXPORT_ALL', 1)
 
     with open('lib_so_pre.js', 'w') as f:
       f.write('''
@@ -3325,6 +3327,9 @@ def zzztest_dlfcn_exceptions(self): # TODO: make this work. need to forward temp
 ''')
 
   def dylink_test(self, main, side, expected, header=None, main_emcc_args=[], force_c=False, need_reverse=True, auto_load=True):
+    # shared settings
+    self.set_setting('EXPORT_ALL', 1)
+
     if header:
       open('header.h', 'w').write(header)
 
@@ -3800,7 +3805,7 @@ def test_dylink_global_var_jslib(self):
       void call_side() {
         printf("side: jslib_x is %d.\n", jslib_x);
       }
-    ''', expected=['main: jslib_x is 148.\nside: jslib_x is 148.\n'], main_emcc_args=['--js-library', 'lib.js'])
+    ''', expected=['main: jslib_x is 148.\nside: jslib_x is 148.\n'], main_emcc_args=['--js-library', 'lib.js', '-s', 'EXPORTED_FUNCTIONS=["_main", "_jslib_x"]'])
 
   @needs_dlfcn
   def test_dylink_many_postSets(self):
@@ -4034,7 +4039,7 @@ def test_dylink_hyper_dupe(self):
         printf("only_in_third_1: %d, %d, %d, %d\n", sidef(), sideg, second_to_third, x);
       }
     ''')
-    run_process([PYTHON, EMCC, 'third.cpp', '-s', 'SIDE_MODULE=1'] + Building.COMPILER_TEST_OPTS + self.emcc_args + ['-o', 'third' + dylib_suffix])
+    run_process([PYTHON, EMCC, 'third.cpp', '-s', 'SIDE_MODULE=1', '-s', 'EXPORT_ALL=1'] + Building.COMPILER_TEST_OPTS + self.emcc_args + ['-o', 'third' + dylib_suffix])
 
     self.dylink_test(main=r'''
       #include <stdio.h>

tests/test_other.py

@@ -3004,7 +3004,8 @@ def test_proxyfs(self):
                  '--embed-file', 'proxyfs_embed.txt', '--pre-js', 'proxyfs_pre.js',
                  '-s', 'EXTRA_EXPORTED_RUNTIME_METHODS=["ccall", "cwrap"]',
                  '-s', 'BINARYEN_ASYNC_COMPILATION=0',
-                 '-s', 'MAIN_MODULE=1'])
+                 '-s', 'MAIN_MODULE=1',
+                 '-s', 'EXPORT_ALL=1'])
     # Following shutil.copyfile just prevent 'require' of node.js from caching js-object.
     # See https://nodejs.org/api/modules.html
     shutil.copyfile('proxyfs_test.js', 'proxyfs_test1.js')
@@ -6230,7 +6231,7 @@ def test(main_args=[], library_args=[], expected='hello from main\nhello from li
           #endif
           }
         ''')
-        run_process([PYTHON, EMCC, 'library.c', '-s', 'SIDE_MODULE=1', '-O2', '-o', library_file, '-s', 'WASM=' + str(wasm)] + library_args)
+        run_process([PYTHON, EMCC, 'library.c', '-s', 'SIDE_MODULE=1', '-O2', '-o', library_file, '-s', 'WASM=' + str(wasm), '-s', 'EXPORT_ALL=1'] + library_args)
         open('main.c', 'w').write(r'''
           #include <dlfcn.h>
           #include <stdio.h>
@@ -6266,12 +6267,14 @@ def percent_diff(x, y):
       full = test()
       # printf is not used in main, but libc was linked in, so it's there
       printf = test(library_args=['-DUSE_PRINTF'])
-      # dce in main, and side happens to be ok since it uses puts as well
-      dce = test(main_args=['-s', 'MAIN_MODULE=2'])
+      # dce in main, and it fails since puts is not exported
+      dce = test(main_args=['-s', 'MAIN_MODULE=2'], expected=('cannot', 'undefined'))
+      # with exporting, it works
+      dce = test(main_args=['-s', 'MAIN_MODULE=2', '-s', 'EXPORTED_FUNCTIONS=["_main", "_puts"]'])
       # printf is not used in main, and we dce, so we failz
       dce_fail = test(main_args=['-s', 'MAIN_MODULE=2'], library_args=['-DUSE_PRINTF'], expected=('cannot', 'undefined'))
       # exporting printf in main keeps it alive for the library
-      dce_save = test(main_args=['-s', 'MAIN_MODULE=2', '-s', 'EXPORTED_FUNCTIONS=["_main", "_printf"]'], library_args=['-DUSE_PRINTF'])
+      dce_save = test(main_args=['-s', 'MAIN_MODULE=2', '-s', 'EXPORTED_FUNCTIONS=["_main", "_printf", "_puts"]'], library_args=['-DUSE_PRINTF'])
 
       assert percent_diff(full[0], printf[0]) < 4
       assert percent_diff(dce[0], dce_fail[0]) < 4
@@ -6377,10 +6380,10 @@ def test_ld_library_path(self):
 
 ''')
 
-    run_process([PYTHON, EMCC, '-o', 'libhello1.wasm', 'hello1.c', '-s', 'SIDE_MODULE=1'])
-    run_process([PYTHON, EMCC, '-o', 'libhello2.wasm', 'hello2.c', '-s', 'SIDE_MODULE=1'])
-    run_process([PYTHON, EMCC, '-o', 'libhello3.wasm', 'hello3.c', '-s', 'SIDE_MODULE=1'])
-    run_process([PYTHON, EMCC, '-o', 'libhello4.wasm', 'hello4.c', '-s', 'SIDE_MODULE=1'])
+    run_process([PYTHON, EMCC, '-o', 'libhello1.wasm', 'hello1.c', '-s', 'SIDE_MODULE=1', '-s', 'EXPORT_ALL=1'])
+    run_process([PYTHON, EMCC, '-o', 'libhello2.wasm', 'hello2.c', '-s', 'SIDE_MODULE=1', '-s', 'EXPORT_ALL=1'])
+    run_process([PYTHON, EMCC, '-o', 'libhello3.wasm', 'hello3.c', '-s', 'SIDE_MODULE=1', '-s', 'EXPORT_ALL=1'])
+    run_process([PYTHON, EMCC, '-o', 'libhello4.wasm', 'hello4.c', '-s', 'SIDE_MODULE=1', '-s', 'EXPORT_ALL=1'])
     run_process([PYTHON, EMCC, '-o', 'main.js', 'main.c', '-s', 'MAIN_MODULE=1', '-s', 'TOTAL_MEMORY=' + str(32 * 1024 * 1024),
                  '--embed-file', 'libhello1.wasm@/lib/libhello1.wasm',
                  '--embed-file', 'libhello2.wasm@/usr/lib/libhello2.wasm',
@@ -6453,8 +6456,8 @@ def test_dlopen_rtld_global(self):
 }
 ''')
 
-    run_process([PYTHON, EMCC, '-o', 'libhello1.js', 'hello1.c', '-s', 'SIDE_MODULE=1', '-s', 'WASM=0'])
-    run_process([PYTHON, EMCC, '-o', 'libhello2.js', 'hello2.c', '-s', 'SIDE_MODULE=1', '-s', 'WASM=0'])
+    run_process([PYTHON, EMCC, '-o', 'libhello1.js', 'hello1.c', '-s', 'SIDE_MODULE=1', '-s', 'WASM=0', '-s', 'EXPORT_ALL=1'])
+    run_process([PYTHON, EMCC, '-o', 'libhello2.js', 'hello2.c', '-s', 'SIDE_MODULE=1', '-s', 'WASM=0', '-s', 'EXPORT_ALL=1'])
     run_process([PYTHON, EMCC, '-o', 'main.js', 'main.c', '-s', 'MAIN_MODULE=1', '-s', 'WASM=0',
                  '--embed-file', 'libhello1.js',
                  '--embed-file', 'libhello2.js'])
@@ -8245,7 +8248,7 @@ def test(filename, expectations):
                  0, [],                         ['tempDoublePtr', 'waka'],     8,   0,    0, 0), # noqa; totally empty!
       # but we don't metadce with linkable code! other modules may want it
       (['-O3', '-s', 'MAIN_MODULE=1'],
-              1489, ['invoke_v'],               ['waka'],                 469663, 149, 1443, None), # noqa; don't compare the # of functions in a main module, which changes a lot
+              1489, ['invoke_v'],               ['waka'],                 226057,  30,   75, None), # noqa; don't compare the # of functions in a main module, which changes a lot
     ]) # noqa
 
     print('test on a minimal pure computational thing')
@@ -8286,9 +8289,9 @@ def test_legalize_js_ffi(self):
     # test disabling of JS FFI legalization
     wasm_dis = os.path.join(Building.get_binaryen_bin(), 'wasm-dis')
     for (args, js_ffi) in [
-        (['-s', 'LEGALIZE_JS_FFI=1', '-s', 'SIDE_MODULE=1', '-O2'], True),
-        (['-s', 'LEGALIZE_JS_FFI=0', '-s', 'SIDE_MODULE=1', '-O2'], False),
-        (['-s', 'LEGALIZE_JS_FFI=0', '-s', 'SIDE_MODULE=1', '-O0'], False),
+        (['-s', 'LEGALIZE_JS_FFI=1', '-s', 'SIDE_MODULE=1', '-O2', '-s', 'EXPORT_ALL=1'], True),
+        (['-s', 'LEGALIZE_JS_FFI=0', '-s', 'SIDE_MODULE=1', '-O2', '-s', 'EXPORT_ALL=1'], False),
+        (['-s', 'LEGALIZE_JS_FFI=0', '-s', 'SIDE_MODULE=1', '-O0', '-s', 'EXPORT_ALL=1'], False),
         (['-s', 'LEGALIZE_JS_FFI=0', '-s', 'WARN_ON_UNDEFINED_SYMBOLS=0', '-O0'], False),
       ]:
       if self.is_wasm_backend() and 'SIDE_MODULE=1' in args: