basic support for dynamic_cast

emscripten-core · Nov 8, 2011 · 6fe0acc · 6fe0acc
1 parent 938b121
commit 6fe0acc
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diff --git a/src/library.js b/src/library.js
@@ -4051,6 +4051,27 @@ LibraryManager.library = {
     return 1;
   },
 
+  _ZTVN10__cxxabiv117__class_type_infoE: [1], // no inherited classes
+  _ZTVN10__cxxabiv120__si_class_type_infoE: [2], // yes inherited classes
+
+  __dynamic_cast: function(ptr, knownTI, attemptedTI, idunno) {
+    var ptrTV = {{{ makeGetValue('ptr', '0', '*') }}};
+    var count = {{{ makeGetValue('ptrTV', '0', '*') }}};
+    ptrTV -= {{{ QUANTUM_SIZE }}};
+    var TI = {{{ makeGetValue('ptrTV', '0', '*') }}};
+    do {
+      if (TI == attemptedTI) return 1;
+      // Go to parent class
+      var type_infoAddr = {{{ makeGetValue('TI', '0', '*') }}} - {{{ QUANTUM_SIZE*2 }}};
+      var type_info = {{{ makeGetValue('type_infoAddr', '0', '*') }}};
+      if (type_info == 1) return 0; // no parent class
+      var TIAddr = TI + {{{ QUANTUM_SIZE*2 }}};
+      var TI = {{{ makeGetValue('TIAddr', '0', '*') }}};
+    } while (1);
+
+    return 0;
+  },
+
   // Exceptions
   __cxa_allocate_exception: function(size) {
     return _malloc(size);

diff --git a/tests/runner.py b/tests/runner.py
@@ -1063,6 +1063,37 @@ def test_polymorph(self):
         '''
         self.do_run(src, '*11,74,32,1012*\n*11*\n*22*')
 
+    def test_dynamic_cast(self):
+        src = '''
+          #include <stdio.h>
+
+          class CBase { virtual void dummy() {} };
+          class CDerived : public CBase { int a; };
+          class CDerivedest : public CDerived { float b; };
+
+          int main ()
+          {
+            CBase *pa = new CBase;
+            CBase *pb = new CDerived;
+            CBase *pc = new CDerivedest;
+
+            printf("a1: %d\\n", dynamic_cast<CDerivedest*>(pa) != NULL);
+            printf("a2: %d\\n", dynamic_cast<CDerived*>(pa) != NULL);
+            printf("a3: %d\\n", dynamic_cast<CBase*>(pa) != NULL);
+
+            printf("b1: %d\\n", dynamic_cast<CDerivedest*>(pb) != NULL);
+            printf("b2: %d\\n", dynamic_cast<CDerived*>(pb) != NULL);
+            printf("b3: %d\\n", dynamic_cast<CBase*>(pb) != NULL);
+
+            printf("c1: %d\\n", dynamic_cast<CDerivedest*>(pc) != NULL);
+            printf("c2: %d\\n", dynamic_cast<CDerived*>(pc) != NULL);
+            printf("c3: %d\\n", dynamic_cast<CBase*>(pc) != NULL);
+
+            return 0;
+          }
+        '''
+        self.do_run(src, 'a1: 0\na2: 0\na3: 1\nb1: 0\nb2: 1\nb3: 1\nc1: 1\nc2: 1\nc3: 1\n')
+
     def test_funcptr(self):
         src = '''
           #include <stdio.h>