Enable longjmp + pthreads + dylink

The underlying bug that caused this configuration
not to work (lack of TLS import/export) was fixed
in #14971.

Fixes: #14461

Author: sbc100

emcc.py

@@ -2015,10 +2015,6 @@ def include_and_export(name):
       elif settings.LINKABLE:
         diagnostics.warning('experimental', '-s LINKABLE + pthreads is experimental')
 
-      default_setting('SUPPORT_LONGJMP', 0)
-      if settings.SUPPORT_LONGJMP:
-        exit_with_error('SUPPORT_LONGJMP is not compatible with pthreads + dynamic linking')
-
     if settings.PROXY_TO_WORKER:
       exit_with_error('--proxy-to-worker is not supported with -s USE_PTHREADS>0! Use the option -s PROXY_TO_PTHREAD=1 if you want to run the main thread of a multithreaded application in a web worker.')
   elif settings.PROXY_TO_PTHREAD:

tests/core/pthread/test_pthread_dylink_longjmp.c

@@ -0,0 +1,24 @@
+#include <assert.h>
+#include <setjmp.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+void longjmp_side();
+
+int main() {
+  jmp_buf buf;
+  int jmpval = setjmp(buf);
+  if (!jmpval) {
+    printf("setjmp done\n");
+    longjmp_side(&buf);
+    // should never get here
+    assert(false);
+  } else if (jmpval == 42) {
+    printf("longjmp done\n");
+  } else {
+    assert(false);
+  }
+
+  printf("Done");
+  return 0;
+}

tests/core/pthread/test_pthread_dylink_longjmp.out

@@ -0,0 +1,3 @@
+setjmp done
+longjmp done
+Done

tests/core/pthread/test_pthread_dylink_longjmp_side.c

@@ -0,0 +1,5 @@
+#include <setjmp.h>
+
+void longjmp_side(jmp_buf* buf) {
+  longjmp(*buf, 42); // jumps back to where setjmp was called
+}

tests/test_core.py

@@ -8549,6 +8549,16 @@ def test_pthread_dylink_tls(self):
     main = test_file('core/pthread/test_pthread_dylink_tls.c')
     self.dylink_testf(main, need_reverse=False)
 
+  @needs_dylink
+  @node_pthreads
+  def test_pthread_dylink_longjmp(self):
+    self.emcc_args.append('-Wno-experimental')
+    self.set_setting('EXIT_RUNTIME')
+    self.set_setting('USE_PTHREADS')
+    self.set_setting('PTHREAD_POOL_SIZE=1')
+    main = test_file('core/pthread/test_pthread_dylink_longjmp.c')
+    self.dylink_testf(main, need_reverse=False)
+
   @needs_dylink
   @node_pthreads
   def test_Module_dynamicLibraries_pthreads(self):

tests/test_other.py

@@ -1675,10 +1675,6 @@ def test_dylink_pthread_warning(self):
     err = self.expect_fail([EMCC, '-Werror', '-sMAIN_MODULE', '-sUSE_PTHREADS', test_file('hello_world.c')])
     self.assertContained('error: -s MAIN_MODULE + pthreads is experimental', err)
 
-  def test_dylink_pthread_longjmp(self):
-    err = self.expect_fail([EMCC, '-sMAIN_MODULE', '-sUSE_PTHREADS', '-sSUPPORT_LONGJMP', test_file('hello_world.c')])
-    self.assertContained('SUPPORT_LONGJMP is not compatible with pthreads + dynamic linking', err)
-
   def test_dylink_no_autoload(self):
     create_file('main.c', r'''
       #include <stdio.h>