Implement self-dlopen.

5 files changed, 88 insertions, 37 deletions

diff --git a/emscripten.py b/emscripten.py
index d9367566..921ab879 100755
--- a/emscripten.py
+++ b/emscripten.py
@@ -620,6 +620,16 @@ Runtime.stackRestore = function(top) { asm['stackRestore'](top) };
 // EMSCRIPTEN_END_FUNCS
 ''']
 
+  # Create symbol table for self-dlopen
+  if settings.get('LINKABLE'):
+    GLOBAL_BASE = forwarded_json['Runtime']['GLOBAL_BASE']
+    symbol_table = {k:v+8 for k,v in forwarded_json['Variables']['indexedGlobals'].iteritems()}
+    for raw in last_forwarded_json['Functions']['tables'].itervalues():
+      table = raw[raw.find('[')+1:raw.find(']')].split(",")
+      symbol_table.update(map(lambda x: (x[1], x[0]),
+        filter(lambda x: x[1] != '0', enumerate(table))))
+    outfile.write("var SYMBOL_TABLE = %s;" % json.dumps(symbol_table))
+
   for funcs_js_item in funcs_js: # do this loop carefully to save memory
     funcs_js_item = indexize(funcs_js_item)
     funcs_js_item = blockaddrsize(funcs_js_item)
diff --git a/src/jsifier.js b/src/jsifier.js
index 82b78d0a..bc073aaa 100644
--- a/src/jsifier.js
+++ b/src/jsifier.js
@@ -602,6 +602,8 @@ function JSify(data, functionsOnly, givenFunctions) {
           var associatedSourceFile = "NO_SOURCE";
       }
       
+      if (LINKABLE) Functions.getIndex(func.ident);
+
       func.JS += 'function ' + func.ident + '(' + paramIdents.join(', ') + ') {\n';
 
       if (PGO) {
diff --git a/src/library.js b/src/library.js
index bf969fd7..19452bb1 100644
--- a/src/library.js
+++ b/src/library.js
@@ -5886,7 +5886,7 @@ LibraryManager.library = {
   dlopen: function(filename, flag) {
     // void *dlopen(const char *file, int mode);
     // http://pubs.opengroup.org/onlinepubs/009695399/functions/dlopen.html
-    filename = (ENV['LD_LIBRARY_PATH'] || '/') + Pointer_stringify(filename);
+    filename = filename === 0 ? '__self__' : (ENV['LD_LIBRARY_PATH'] || '/') + Pointer_stringify(filename);
 
     if (DLFCN_DATA.loadedLibNames[filename]) {
       // Already loaded; increment ref count and return.
@@ -5895,48 +5895,55 @@ LibraryManager.library = {
       return handle;
     }
 
-    var target = FS.findObject(filename);
-    if (!target || target.isFolder || target.isDevice) {
-      DLFCN_DATA.errorMsg = 'Could not find dynamic lib: ' + filename;
-      return 0;
+    if (filename === '__self__') {
+      var handle = -1;
+      var lib_module = Module;
+      var cached_functions = SYMBOL_TABLE;
     } else {
-      FS.forceLoadFile(target);
-      var lib_data = intArrayToString(target.contents);
-    }
+      var target = FS.findObject(filename);
+      if (!target || target.isFolder || target.isDevice) {
+        DLFCN_DATA.errorMsg = 'Could not find dynamic lib: ' + filename;
+        return 0;
+      } else {
+        FS.forceLoadFile(target);
+        var lib_data = intArrayToString(target.contents);
+      }
 
-    try {
-      var lib_module = eval(lib_data)({{{ Functions.getTable('x') }}}.length);
-    } catch (e) {
+      try {
+        var lib_module = eval(lib_data)({{{ Functions.getTable('x') }}}.length);
+      } catch (e) {
 #if ASSERTIONS
-      Module.printErr('Error in loading dynamic library: ' + e);
+        Module.printErr('Error in loading dynamic library: ' + e);
 #endif
-      DLFCN_DATA.errorMsg = 'Could not evaluate dynamic lib: ' + filename;
-      return 0;
-    }
+        DLFCN_DATA.errorMsg = 'Could not evaluate dynamic lib: ' + filename;
+        return 0;
+      }
 
-    // Not all browsers support Object.keys().
-    var handle = 1;
-    for (var key in DLFCN_DATA.loadedLibs) {
-      if (DLFCN_DATA.loadedLibs.hasOwnProperty(key)) handle++;
-    }
+      // Not all browsers support Object.keys().
+      var handle = 1;
+      for (var key in DLFCN_DATA.loadedLibs) {
+        if (DLFCN_DATA.loadedLibs.hasOwnProperty(key)) handle++;
+      }
 
+      // We don't care about RTLD_NOW and RTLD_LAZY.
+      if (flag & 256) { // RTLD_GLOBAL
+        for (var ident in lib_module) {
+          if (lib_module.hasOwnProperty(ident)) {
+            Module[ident] = lib_module[ident];
+          }
+        }
+      }
+
+      var cached_functions = {};
+    }
     DLFCN_DATA.loadedLibs[handle] = {
       refcount: 1,
       name: filename,
       module: lib_module,
-      cached_functions: {}
+      cached_functions: cached_functions
     };
     DLFCN_DATA.loadedLibNames[filename] = handle;
 
-    // We don't care about RTLD_NOW and RTLD_LAZY.
-    if (flag & 256) { // RTLD_GLOBAL
-      for (var ident in lib_module) {
-        if (lib_module.hasOwnProperty(ident)) {
-          Module[ident] = lib_module[ident];
-        }
-      }
-    }
-
     return handle;
   },
   // int dlclose(void* handle);
@@ -5968,13 +5975,15 @@ LibraryManager.library = {
       return 0;
     } else {
       var lib = DLFCN_DATA.loadedLibs[handle];
-      if (!lib.module.hasOwnProperty(symbol)) {
-        DLFCN_DATA.errorMsg = ('Tried to lookup unknown symbol "' + symbol +
-                               '" in dynamic lib: ' + lib.name);
-        return 0;
+      // self-dlopen means that lib.module is not a superset of
+      // cached_functions, so check the latter first
+      if (lib.cached_functions.hasOwnProperty(symbol)) {
+        return lib.cached_functions[symbol];
       } else {
-        if (lib.cached_functions.hasOwnProperty(symbol)) {
-          return lib.cached_functions[symbol];
+        if (!lib.module.hasOwnProperty(symbol)) {
+          DLFCN_DATA.errorMsg = ('Tried to lookup unknown symbol "' + symbol +
+                                 '" in dynamic lib: ' + lib.name);
+          return 0;
         } else {
           var result = lib.module[symbol];
           if (typeof result == 'function') {
diff --git a/src/modules.js b/src/modules.js
index a6aa2644..53d97817 100644
--- a/src/modules.js
+++ b/src/modules.js
@@ -449,7 +449,8 @@ var PassManager = {
         Types: Types,
         Variables: Variables,
         Functions: Functions,
-        EXPORTED_FUNCTIONS: EXPORTED_FUNCTIONS // needed for asm.js global constructors (ctors)
+        EXPORTED_FUNCTIONS: EXPORTED_FUNCTIONS, // needed for asm.js global constructors (ctors)
+        Runtime: { GLOBAL_BASE: Runtime.GLOBAL_BASE }
       }));
     } else if (phase == 'funcs') {
       print('\n//FORWARDED_DATA:' + JSON.stringify({
diff --git a/tests/runner.py b/tests/runner.py
index b21eee08..a892eb56 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -5885,6 +5885,35 @@ def process(filename):
       self.do_run(src, '100\n200\n13\n42\n',
                   post_build=add_pre_run_and_checks)
 
+    def test_dlfcn_self(self):
+      if Settings.USE_TYPED_ARRAYS == 1: return self.skip('Does not work with USE_TYPED_ARRAYS=1')
+      Settings.LINKABLE = 1
+
+      src = r'''
+#include <stdio.h>
+#include <dlfcn.h>
+
+int global = 123;
+
+extern "C" __attribute__((noinline)) void foo(int x) {
+  printf("%d\n", x);
+}
+
+void repeatable() {
+  void* self = dlopen(NULL, RTLD_LAZY);
+  int* global_ptr = (int*)dlsym(self, "global");
+  void (*foo_ptr)(int) = (void (*)(int))dlsym(self, "foo");
+  foo_ptr(*global_ptr);
+  dlclose(self);
+}
+
+int main() {
+  repeatable();
+  repeatable();
+  return 0;
+}'''
+      self.do_run(src, '123\n123')
+
     def test_rand(self):
       return self.skip('rand() is now random') # FIXME