Wasm backend pthreads testing improvements (#8842)

 *   After #8811 landed a lot more tests can pass, this enables all those that can.
 *   Remove unnecessary stuff in test_pthread_gcc_atomic_fetch_and_op.
 *   Add more runtime assertions for the stack position.

There are still a few tests that don't pass, so this doesn't close #8718. But they are quite few at this point (and look unrelated to stack issues - something else going on there).

src/worker.js

@@ -191,8 +191,14 @@ this.onmessage = function(e) {
       assert(selfThreadId);
       assert(parentThreadId);
       assert(STACK_BASE != 0);
-#if !WASM_BACKEND
-      assert(STACK_MAX > STACK_BASE);
+#if WASM_BACKEND
+      assert(max === e.data.stackBase);
+      assert(top > max);
+      assert(e.data.stackBase == max);
+#else
+      assert(max > e.data.stackBase);
+      assert(max > top);
+      assert(e.data.stackBase === top);
 #endif
 #endif
       // Call inside asm.js/wasm module to set up the stack frame for this pthread in asm.js/wasm module scope

tests/test_browser.py

@@ -3538,13 +3538,11 @@ def prep_no_SAB(self):
 
   # Test that the emscripten_ atomics api functions work.
   @requires_threads
-  @no_wasm_backend('TODO - fix final pthreads tests (#8718)')
   def test_pthread_atomics(self):
     self.btest(path_from_root('tests', 'pthread', 'test_pthread_atomics.cpp'), expected='0', args=['-s', 'TOTAL_MEMORY=64MB', '-O3', '-s', 'USE_PTHREADS=1', '-s', 'PTHREAD_POOL_SIZE=8'])
 
   # Test 64-bit atomics.
   @requires_threads
-  @flaky # TODO - fix final pthreads tests (#8718)
   def test_pthread_64bit_atomics(self):
     self.btest(path_from_root('tests', 'pthread', 'test_pthread_64bit_atomics.cpp'), expected='0', args=['-s', 'TOTAL_MEMORY=64MB', '-O3', '-s', 'USE_PTHREADS=1', '-s', 'PTHREAD_POOL_SIZE=8'])
 
@@ -3557,17 +3555,17 @@ def test_pthread_64bit_cxx11_atomics(self):
 
   # Test the old GCC atomic __sync_fetch_and_op builtin operations.
   @requires_threads
-  @no_wasm_backend('TODO - fix final pthreads tests (#8718)')
   def test_pthread_gcc_atomic_fetch_and_op(self):
     # We need to resort to using regexes to optimize out SharedArrayBuffer when pthreads are not supported, which is brittle!
     # Therefore perform very extensive testing of different codegen modes to catch any problems.
-    for opt in [[], ['-O1'], ['-O2'], ['-O3'], ['-O3', '-s', 'AGGRESSIVE_VARIABLE_ELIMINATION=1'], ['-Os'], ['-Oz']]:
+    for opt in [[], ['-O1'], ['-O2'], ['-O3'], ['-O3', '-s', 'AGGRESSIVE_VARIABLE_ELIMINATION=1'], ['-Os']]:
       for debug in [[], ['-g1'], ['-g2'], ['-g4']]:
         for f32 in [[], ['-s', 'PRECISE_F32=1', '--separate-asm', '-s', 'WASM=0']]:
-          print(opt, debug, f32)
-          if self.is_wasm_backend() and '--separate-asm' in f32:
+          args = opt + debug + f32
+          print(args)
+          if self.is_wasm_backend() and '--separate-asm' in args or 'AGGRESSIVE_VARIABLE_ELIMINATION=1' in args:
             continue
-          self.btest(path_from_root('tests', 'pthread', 'test_pthread_gcc_atomic_fetch_and_op.cpp'), expected='0', args=opt + debug + f32 + ['-s', 'TOTAL_MEMORY=64MB', '-s', 'USE_PTHREADS=1', '-s', 'PTHREAD_POOL_SIZE=8'])
+          self.btest(path_from_root('tests', 'pthread', 'test_pthread_gcc_atomic_fetch_and_op.cpp'), expected='0', args=args + ['-s', 'TOTAL_MEMORY=64MB', '-s', 'USE_PTHREADS=1', '-s', 'PTHREAD_POOL_SIZE=8'])
 
   # 64 bit version of the above test.
   @requires_threads
@@ -3590,15 +3588,13 @@ def test_pthread_gcc_atomics(self):
     self.btest(path_from_root('tests', 'pthread', 'test_pthread_gcc_atomics.cpp'), expected='0', args=['-s', 'TOTAL_MEMORY=64MB', '-O3', '-s', 'USE_PTHREADS=1', '-s', 'PTHREAD_POOL_SIZE=8'])
 
   # Test the __sync_lock_test_and_set and __sync_lock_release primitives.
-  @no_wasm_backend('TODO - fix final pthreads tests (#8718)')
   @requires_threads
   def test_pthread_gcc_spinlock(self):
     for arg in [[], ['-DUSE_EMSCRIPTEN_INTRINSICS']]:
       self.btest(path_from_root('tests', 'pthread', 'test_pthread_gcc_spinlock.cpp'), expected='800', args=['-s', 'TOTAL_MEMORY=64MB', '-O3', '-s', 'USE_PTHREADS=1', '-s', 'PTHREAD_POOL_SIZE=8'] + arg, also_asmjs=True)
 
   # Test that basic thread creation works.
   @requires_threads
-  @no_wasm_backend('TODO - fix final pthreads tests (#8718)')
   def test_pthread_create(self):
     def test(args):
       print(args)
@@ -3615,7 +3611,6 @@ def test_pthread_proxy_to_pthread(self):
 
   # Test that a pthread can spawn another pthread of its own.
   @requires_threads
-  @no_wasm_backend('TODO - fix final pthreads tests (#8718)')
   def test_pthread_create_pthread(self):
     for modularize in [[], ['-s', 'MODULARIZE=1', '-s', 'EXPORT_NAME=MyModule', '--shell-file', path_from_root('tests', 'shell_that_launches_modularize.html')]]:
       self.btest(path_from_root('tests', 'pthread', 'test_pthread_create_pthread.cpp'), expected='1', args=['-O3', '-s', 'USE_PTHREADS=1', '-s', 'PTHREAD_POOL_SIZE=2'] + modularize)
@@ -3632,7 +3627,6 @@ def test_pthread_join(self):
 
   # Test that threads can rejoin the pool once detached and finished
   @requires_threads
-  @no_wasm_backend('TODO - fix final pthreads tests (#8718)')
   def test_std_thread_detach(self):
     self.btest(path_from_root('tests', 'pthread', 'test_std_thread_detach.cpp'), expected='0', args=['-std=c++11', '-s', 'USE_PTHREADS=1'])
 
@@ -3796,7 +3790,6 @@ def test_pthread_proxying_in_futex_wait(self):
     self.btest(path_from_root('tests', 'pthread', 'test_pthread_proxying_in_futex_wait.cpp'), expected='0', args=['-O3', '-s', 'USE_PTHREADS=1', '-s', 'PTHREAD_POOL_SIZE=1'])
 
   # Test that sbrk() operates properly in multithreaded conditions
-  @no_wasm_backend('TODO - fix final pthreads tests (#8718)')
   @requires_threads
   def test_pthread_sbrk(self):
     for aborting_malloc in [0, 1]: