Honor -Bstatic and -Bdynamic and pass these down the wasm-ld

Author: sbc100

emcc.py

@@ -370,7 +370,7 @@ def get_next_arg():
         add_link_arg(flag)
     elif arg == '-Xlinker':
       add_link_arg(get_next_arg())
-    elif arg == '-s' or arg.startswith(('-l', '-L', '--js-library=', '-z', '-u')):
+    elif arg in {'-s', '-Bstatic', '-Bdynamic'} or arg.startswith(('-l', '-L', '--js-library=', '-z', '-u')):
       add_link_arg(arg)
     elif not arg.startswith('-o') and arg not in {'-nostdlib', '-nostartfiles', '-nolibc', '-nodefaultlibs', '-s'}:
       # All other flags are for the compiler

test/test_other.py

@@ -2428,6 +2428,44 @@ def test_dylink_LEGACY_GL_EMULATION(self):
 }''')
     self.do_runf('test.c', 'done\n', cflags=['-sLEGACY_GL_EMULATION', '-sMAIN_MODULE=2'])
 
+  def test_dylink_library_search(self):
+    # Test library resolution in the case when both static and dynamic library are present.
+    create_file('side_dyn.c', r'''
+      #include <stdio.h>
+      void side_func() {
+        printf("dynamic linking used\n");
+      }
+    ''')
+    create_file('side_static.c', r'''
+      #include <stdio.h>
+      void side_func() {
+        printf("static linking used\n");
+      }
+    ''')
+    self.emcc('side_dyn.c', ['-sSIDE_MODULE', '-olibside.so'])
+    self.emcc('side_static.c', ['-oside_static.o', '-c'])
+    self.run_process([EMAR, 'rc', 'libside.a', 'side_static.o'])
+
+    create_file('main.c', '''
+      void side_func();
+      int main() {
+        side_func();
+        return 0;
+      }
+    ''')
+
+    # By deafult we use static linking and prefer libside.a
+    self.do_runf('main.c', 'static linking used\n', cflags=['-L.', '-lside'])
+
+    # When using -sMAIN_MODULE we choose the dyanmic library
+    self.do_runf('main.c', 'dynamic linking used\n', cflags=['-sMAIN_MODULE=2', '-L.', '-lside'])
+
+    # Same for `-sFAKE_DYLIBC=0
+    self.do_runf('main.c', 'dynamic linking used\n', cflags=['-sFAKE_DYLIBS=0', '-L.', '-lside'])
+
+    # With can also force static linking using `-Bstatic` linker falgs
+    self.do_runf('main.c', 'static linking used\n', cflags=['-sMAIN_MODULE=2', '-L.', '-Bstatic', '-lside'])
+
   def test_js_link(self):
     create_file('before.js', '''
       var MESSAGE = 'hello from js';
@@ -12086,7 +12124,7 @@ def test_shared_flag(self):
     self.assertContained('emcc: warning: ignoring dynamic library libother.so when generating an object file, this will need to be included explicitly in the final link', err)
     self.assertIsObjectFile('out.foo')
 
-    # Test that adding `-sFAKE_DYIBS=0` build a real side module
+    # Test that adding `-sFAKE_DYLIBS=0` build a real side module
     err = self.run_process([EMCC, '-shared', '-fPIC', '-sFAKE_DYLIBS=0', test_file('hello_world.c'), '-o', 'out.foo', 'libother.so'], stderr=PIPE).stderr
     self.assertNotContained('linking a library with `-shared` will emit a static object', err)
     self.assertNotContained('emcc: warning: ignoring dynamic library libother.so when generating an object file, this will need to be included explicitly in the final link', err)

tools/link.py

@@ -773,12 +773,19 @@ def get_dylibs(options, linker_args):
   This can either be via `-lfoo` or via `libfoo.so` directly.
   """
   dylibs = []
+  # Mimic the behavior of the native linker WRT to the `-Bstack/-Bdynamic` flags.
+  search_for_dylibs = True
   for arg in linker_args:
-    if arg.startswith('-l'):
-      for ext in DYLIB_EXTENSIONS:
-        path = find_library('lib' + arg[2:] + ext, options.lib_dirs)
-        if path and building.is_wasm_dylib(path):
-          dylibs.append(path)
+    if arg in {'-Bstatic', '-static'}:
+      search_for_dylibs = False
+    elif arg == '-Bdynamic':
+      search_for_dylibs = True
+    elif arg.startswith('-l'):
+      if search_for_dylibs:
+        for ext in DYLIB_EXTENSIONS:
+          path = find_library('lib' + arg[2:] + ext, options.lib_dirs)
+          if path and building.is_wasm_dylib(path):
+            dylibs.append(path)
     elif building.is_wasm_dylib(arg):
       dylibs.append(arg)
   return dylibs