Avoid setting EXPORTED_FUNCTIONS with MAIN_MODULE=1 (#15257)

This setting is meaningless with MAIN_MODULE=1 or SIDE_MODULE=1.
Hopefully this will be a warning soon:
#10075

Also avoid using C++ in some tests that don't need it.

Author: sbc100

tests/test_core.py

@@ -2722,8 +2722,7 @@ class Bar {
 
   @needs_dylink
   def test_dlfcn_qsort(self):
-    self.set_setting('EXPORTED_FUNCTIONS', ['_get_cmp'])
-    create_file('liblib.cpp', '''
+    create_file('liblib.c', '''
       int lib_cmp(const void* left, const void* right) {
         const int* a = (const int*) left;
         const int* b = (const int*) right;
@@ -2734,14 +2733,13 @@ def test_dlfcn_qsort(self):
 
       typedef int (*CMP_TYPE)(const void*, const void*);
 
-      extern "C" CMP_TYPE get_cmp() {
+      CMP_TYPE get_cmp() {
         return lib_cmp;
       }
       ''')
-    self.build_dlfcn_lib('liblib.cpp')
+    self.build_dlfcn_lib('liblib.c')
 
     self.prep_dlfcn_main()
-    self.set_setting('EXPORTED_FUNCTIONS', ['_main', '_malloc'])
     src = '''
       #include <stdio.h>
       #include <stdlib.h>
@@ -2800,7 +2798,7 @@ def test_dlfcn_data_and_fptr(self):
     if self.is_wasm():
       self.banned_js_engines = [config.V8_ENGINE]
 
-    create_file('liblib.cpp', r'''
+    create_file('liblib.c', r'''
       #include <stdio.h>
 
       int theglobal = 42;
@@ -2820,14 +2818,13 @@ def test_dlfcn_data_and_fptr(self):
         p_f();
       }
 
-      extern "C" void (*func(int x, void(*fptr)()))() {
+      void (*func(int x, void(*fptr)()))() {
         printf("In func: %d\n", x);
         fptr();
         return lib_fptr;
       }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_func'])
-    self.build_dlfcn_lib('liblib.cpp')
+    self.build_dlfcn_lib('liblib.c')
 
     self.prep_dlfcn_main()
     src = r'''
@@ -2883,29 +2880,27 @@ def test_dlfcn_data_and_fptr(self):
         return 0;
       }
       '''
-    self.set_setting('EXPORTED_FUNCTIONS', ['_main'])
     self.do_run(src, '''\
 In func: 13
 First calling main_fptr from lib.
 Second calling lib_fptr from main.
 parent_func called from child
 parent_func called from child
 Var: 42
-''')
+''', force_c=True)
 
   @needs_dylink
   def test_dlfcn_varargs(self):
     # this test is not actually valid - it fails natively. the child should fail
     # to be loaded, not load and successfully see the parent print_ints func
 
-    create_file('liblib.cpp', r'''
+    create_file('liblib.c', r'''
       void print_ints(int n, ...);
-      extern "C" void func() {
+      void func() {
         print_ints(2, 13, 42);
       }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_func'])
-    self.build_dlfcn_lib('liblib.cpp')
+    self.build_dlfcn_lib('liblib.c')
 
     self.prep_dlfcn_main()
     src = r'''
@@ -2937,8 +2932,7 @@ def test_dlfcn_varargs(self):
         return 0;
       }
       '''
-    self.set_setting('EXPORTED_FUNCTIONS', ['_main'])
-    self.do_run(src, '100\n200\n13\n42\n')
+    self.do_run(src, '100\n200\n13\n42\n', force_c=True)
 
   @needs_dylink
   def test_dlfcn_alignment_and_zeroing(self):
@@ -3040,7 +3034,6 @@ def test_dlfcn_unique_sig(self):
         return 13;
       }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_myfunc'])
     self.build_dlfcn_lib('liblib.c')
 
     self.prep_dlfcn_main()
@@ -3067,7 +3060,6 @@ def test_dlfcn_unique_sig(self):
         return 0;
       }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_main', '_malloc'])
     self.do_runf('main.c', 'success')
 
   @needs_dylink
@@ -3079,7 +3071,6 @@ def test_dlfcn_info(self):
         return 13;
       }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_myfunc'])
     self.build_dlfcn_lib('liblib.c')
 
     self.prep_dlfcn_main()
@@ -3121,7 +3112,6 @@ def test_dlfcn_info(self):
         return 0;
       }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_main', '_malloc'])
     self.do_runf('main.c', 'success')
 
   @needs_dylink
@@ -3141,7 +3131,6 @@ def test_dlfcn_stacks(self):
         return strlen(bigstack);
       }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_myfunc'])
     self.build_dlfcn_lib('liblib.c')
 
     self.prep_dlfcn_main()
@@ -3176,7 +3165,6 @@ def test_dlfcn_stacks(self):
         return 0;
       }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_main', '_malloc', '_strcmp'])
     self.do_runf('main.c', 'success')
 
   @needs_dylink
@@ -3212,7 +3200,6 @@ def test_dlfcn_funcs(self):
         }
       }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_callvoid', '_callint', '_getvoid', '_getint'])
     self.build_dlfcn_lib('liblib.c')
 
     self.prep_dlfcn_main()
@@ -3263,7 +3250,6 @@ def test_dlfcn_funcs(self):
         return 0;
       }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_main', '_malloc'])
     self.do_runf('main.c', '''go
 void_main.
 int_main 201
@@ -3288,11 +3274,9 @@ def test_dlfcn_mallocs(self):
       void *mallocproxy(int n) { return malloc(n); }
       void freeproxy(void *p) { free(p); }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_mallocproxy', '_freeproxy'])
     self.build_dlfcn_lib('liblib.c')
 
     self.prep_dlfcn_main()
-    self.set_setting('EXPORTED_FUNCTIONS', ['_main', '_malloc', '_free'])
     self.do_runf(test_file('dlmalloc_proxy.c'), '*294,153*')
 
   @needs_dylink
@@ -3340,7 +3324,6 @@ def test_dlfcn_longjmp(self):
         return 0;
       }
       ''')
-    self.set_setting('EXPORTED_FUNCTIONS', ['_main', '_malloc', '_free'])
     self.do_runf('main.c', '''go!
 pre 1
 pre 2
@@ -3412,7 +3395,6 @@ def zzztest_dlfcn_exceptions(self):
         return 0;
       }
       '''
-    self.set_setting('EXPORTED_FUNCTIONS', ['_main', '_malloc', '_free'])
     self.do_run(src, '''go!
 ok: 65
 int 123
@@ -3430,8 +3412,9 @@ def indir(name):
     create_file('a.cpp', r'''
       #include <stdio.h>
 
-      static struct a {
-        a() {
+      static class A {
+      public:
+        A() {
           puts("a: loaded");
         }
       } _;
@@ -3440,8 +3423,9 @@ def indir(name):
     create_file('b.cpp', r'''
       #include <stdio.h>
 
-      static struct b {
-        b() {
+      static class B {
+      public:
+        B() {
           puts("b: loaded");
         }
       } _;
@@ -3490,12 +3474,12 @@ def indir(name):
   def test_dlfcn_feature_in_lib(self):
     self.emcc_args.append('-mnontrapping-fptoint')
 
-    create_file('liblib.cpp', r'''
-        extern "C" int magic(float x) {
+    create_file('liblib.c', r'''
+        int magic(float x) {
           return __builtin_wasm_trunc_saturate_s_i32_f32(x);
         }
       ''')
-    self.build_dlfcn_lib('liblib.cpp')
+    self.build_dlfcn_lib('liblib.c')
 
     self.prep_dlfcn_main()
     src = r'''