Triage and enable all possible wasm backend tests (#9040)

I went through all the tests marked as no_wasm_backend. A fair bit now work! Those are enabled here.

I clarified some comments on the non-working ones, and filed issues for the small number that seem like they should pass, or at least are in need of looking into, and linked them.

Some tiny test fixes were needed in some cases. I also fixed a tiny bug in llvm_opt for the wasm backend, which it turns out is only used in the one place in one test.

Author: kripken

tests/test_browser.py

@@ -144,7 +144,6 @@ def test_sdl1(self):
   # Deliberately named as test_zzz_* to make this test the last one
   # as this test may take the focus away from the main test window
   # by opening a new window and possibly not closing it.
-  @no_wasm_backend('wasm source maps')
   def test_zzz_html_source_map(self):
     if not has_browser():
       self.skipTest('need a browser')
@@ -174,9 +173,9 @@ def test_zzz_html_source_map(self):
     # sourceContent when the maps are relative paths
     try_delete(html_file)
     try_delete(html_file + '.map')
-    self.compile_btest(['src.cpp', '-o', 'src.html', '-g4', '-s', 'WASM=0'])
+    self.compile_btest(['src.cpp', '-o', 'src.html', '-g4'])
     self.assertExists(html_file)
-    self.assertExists(html_file + '.map')
+    self.assertExists('src.wasm.map')
     webbrowser.open_new('file://' + html_file)
     print('''
 If manually bisecting:
@@ -187,10 +186,9 @@ def test_zzz_html_source_map(self):
 
   @no_wasm_backend('wasm source maps')
   def test_emscripten_log(self):
-    # TODO: wasm support for source maps
+    # TODO: wasm support for source maps. emscripten_loadSourceMap looks at $HTML.map but it should be $NAME.wasm.map.
     src = 'src.cpp'
     create_test_file(src, self.with_report_result(open(path_from_root('tests', 'emscripten_log', 'emscripten_log.cpp')).read()))
-
     self.compile_btest([src, '--pre-js', path_from_root('src', 'emscripten-source-map.min.js'), '-g', '-o', 'page.html', '-s', 'DEMANGLE_SUPPORT=1', '-s', 'WASM=0'])
     self.run_browser('page.html', None, '/report_result?1')
 
@@ -2194,9 +2192,10 @@ def test_openal_error(self):
   def test_openal_capture_sanity(self):
     self.btest('openal_capture_sanity.c', expected='0')
 
-  @no_wasm_backend('dynamic linking')
   def test_runtimelink(self):
     for wasm in [0, 1]:
+      if not wasm and self.is_wasm_backend():
+        continue
       print(wasm)
       main, supp = self.setup_runtimelink_test()
       create_test_file('supp.cpp', supp)
@@ -2395,7 +2394,6 @@ def test_module(self):
     self.compile_btest([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', '-s', 'EXPORT_ALL=1'], expected='8')
 
-  @no_wasm_backend('dynamic linking')
   def test_preload_module(self):
     create_test_file('library.c', r'''
       #include <stdio.h>
@@ -3415,7 +3413,6 @@ def test_webidl(self):
       print(opts)
       self.btest(os.path.join('webidl', 'test.cpp'), '1', args=['--post-js', 'glue.js', '-I.', '-DBROWSER'] + opts)
 
-  @no_wasm_backend('dynamic linking')
   @requires_sync_compilation
   def test_dynamic_link(self):
     create_test_file('pre.js', '''
@@ -3529,7 +3526,6 @@ def do_run(src, expected_output):
 
     super(browser, self)._test_dylink_dso_needed(do_run)
 
-  @no_wasm_backend('dynamic linking')
   @requires_graphics_hardware
   @requires_sync_compilation
   def test_dynamic_link_glemu(self):

tests/test_core.py

@@ -1981,13 +1981,11 @@ def test_biggerswitch(self):
 59899: 598995989959899
 Success!''')
 
-  @no_wasm_backend('no implementation of computed gotos')
   def test_indirectbr(self):
       self.emcc_args = [x for x in self.emcc_args if x != '-g']
 
       self.do_run_in_out_file_test('tests', 'core', 'test_indirectbr')
 
-  @no_wasm_backend('no implementation of computed gotos')
   def test_indirectbr_many(self):
       self.do_run_in_out_file_test('tests', 'core', 'test_indirectbr_many')
 
@@ -2316,7 +2314,7 @@ def test_flexarray_struct(self):
   def test_bsearch(self):
     self.do_run_in_out_file_test('tests', 'core', 'test_bsearch')
 
-  @no_wasm_backend("wasm backend has no support for fastcomp's -emscripten-assertions flag")
+  @no_wasm_backend("https://github.com/emscripten-core/emscripten/issues/9039")
   def test_stack_overflow(self):
     self.set_setting('ASSERTIONS', 1)
     self.do_run(open(path_from_root('tests', 'core', 'stack_overflow.cpp')).read(), 'Stack overflow!')
@@ -3717,7 +3715,6 @@ def test():
       self.assertNotContained("trying to dynamically load symbol '__ZN5ClassC2EPKc' (from 'liblib.so') that already exists", full)
 
   @needs_dlfcn
-  @no_wasm_backend('some kind of issue with dylink and i64')
   def test_dylink_i64(self):
     self.dylink_test(r'''
       #include <stdio.h>
@@ -3749,7 +3746,6 @@ def test_dylink_i64(self):
     ''', 'other says 175a1ddee82b8c31.')
 
   @needs_dlfcn
-  @no_wasm_backend('some kind of issue with dylink and i64')
   def test_dylink_i64_b(self):
     self.dylink_test(r'''
       #include <stdio.h>
@@ -4031,7 +4027,6 @@ def test_dylink_iostream(self):
     ''', expected=['hello from main and hello from side\n'])
 
   @needs_dlfcn
-  @no_wasm_backend('current fails in __dynamic_cast')
   def test_dylink_dynamic_cast(self): # issue 3465
     self.dylink_test(header=r'''
       class Base {
@@ -4113,7 +4108,7 @@ def test_dylink_raii_exceptions(self):
     ''', expected=['special 2.182810 3.141590 42\ndestroy\nfrom side: 1337.\n'])
 
   @needs_dlfcn
-  @no_wasm_backend('wasm backend resolved symbols greedily on startup')
+  @no_wasm_backend('wasm backend resolves symbols greedily on startup')
   def test_dylink_hyper_dupe(self):
     self.set_setting('TOTAL_MEMORY', 64 * 1024 * 1024)
     if not self.has_changed_setting('ASSERTIONS'):
@@ -4187,7 +4182,7 @@ def test_dylink_hyper_dupe(self):
       self.assertContained("warning: symbol '_sideg' from '%s' already exists" % libname, full)
 
   @needs_dlfcn
-  @no_wasm_backend('not implemented yet')
+  @no_wasm_backend('possible https://github.com/emscripten-core/emscripten/issues/9038')
   def test_dylink_dso_needed(self):
     def do_run(src, expected_output):
       self.do_run(src + 'int main() { return _main(); }', expected_output)
@@ -6538,7 +6533,6 @@ def test_demangle_stacks(self):
       self.do_run_in_out_file_test('tests', 'core', 'test_demangle_stacks_noassert')
 
   @no_emterpreter
-  @no_wasm_backend('lld does not generate symbol maps')
   def test_demangle_stacks_symbol_map(self):
     self.set_setting('DEMANGLE_SUPPORT', 1)
     if '-O' in str(self.emcc_args) and '-O0' not in self.emcc_args and '-O1' not in self.emcc_args and '-g' not in self.emcc_args:
@@ -6552,7 +6546,8 @@ def test_demangle_stacks_symbol_map(self):
     for line in symbols:
       if ':' not in line:
         continue
-      short, full = line.split(':')
+      # split by the first ':' (wasm backend demangling may include more :'s later on)
+      short, full = line.split(':', 1)
       if 'Aborter' in full:
         short_aborter = short
         full_aborter = full
@@ -7274,8 +7269,7 @@ def test_async(self, emterpretify=False):
 ''')
       self.do_run(src, 'first\nsecond\n6.4')
 
-  @no_wasm_backend('EMTERPRETIFY causes JSOptimizer to run, which is '
-                   'unsupported with Wasm backend')
+  @no_wasm_backend('EMTERPRETIFY')
   def test_async_emterpretify(self):
     self.test_async(emterpretify=True)
 
@@ -7584,7 +7578,7 @@ def test_fs_dict(self):
     self.do_run('int main() { return 0; }', 'object\nobject\nobject')
 
   @sync
-  @no_wasm_backend("wasm backend has no support for fastcomp's -emscripten-assertions flag")
+  @no_wasm_backend("https://github.com/emscripten-core/emscripten/issues/9039")
   def test_stack_overflow_check(self):
     args = self.emcc_args + ['-s', 'TOTAL_STACK=1048576']