diff --git a/mozilla/base/src/nsByteBufferInputStream.cpp b/mozilla/base/src/nsByteBufferInputStream.cpp
index 161015b1b01..acbef95e5aa 100644
--- a/mozilla/base/src/nsByteBufferInputStream.cpp
+++ b/mozilla/base/src/nsByteBufferInputStream.cpp
@@ -167,7 +167,7 @@ public:
     // nsDummyBufferStream methods:
     nsDummyBufferStream(const char* buffer, PRUint32 length)
         : mBuffer(buffer), mLength(length) {}
-    ~nsDummyBufferStream() {}
+    virtual ~nsDummyBufferStream() {}
 
 protected:
     const char* mBuffer;
diff --git a/mozilla/base/src/nsStr.cpp b/mozilla/base/src/nsStr.cpp
index 153e0240e69..528d321c2ee 100644
--- a/mozilla/base/src/nsStr.cpp
+++ b/mozilla/base/src/nsStr.cpp
@@ -65,7 +65,7 @@ public:
     memset(mPools,0,sizeof(mPools));
   }
 
-  ~nsPoolingMemoryAgent() {
+  virtual ~nsPoolingMemoryAgent() {
     nsBufferDeallocator theDeallocator;
     int i=0;
     for(i=0;i<10;i++){
diff --git a/mozilla/modules/libimg/public_com/nsImgDCallbk.h b/mozilla/modules/libimg/public_com/nsImgDCallbk.h
index e4f14157b67..4335a6e53bc 100644
--- a/mozilla/modules/libimg/public_com/nsImgDCallbk.h
+++ b/mozilla/modules/libimg/public_com/nsImgDCallbk.h
@@ -31,7 +31,7 @@ class ImgDCallbk : public nsIImgDCallbk
 public:
   NS_DECL_ISUPPORTS
   ImgDCallbk(il_container *aContainer) { NS_INIT_ISUPPORTS(); mContainer=aContainer; };
-  ~ImgDCallbk(){};
+  virtual ~ImgDCallbk(){};
 
 
   NS_IMETHOD ImgDCBFlushImage();
diff --git a/mozilla/string/obsolete/nsStr.cpp b/mozilla/string/obsolete/nsStr.cpp
index 153e0240e69..528d321c2ee 100644
--- a/mozilla/string/obsolete/nsStr.cpp
+++ b/mozilla/string/obsolete/nsStr.cpp
@@ -65,7 +65,7 @@ public:
     memset(mPools,0,sizeof(mPools));
   }
 
-  ~nsPoolingMemoryAgent() {
+  virtual ~nsPoolingMemoryAgent() {
     nsBufferDeallocator theDeallocator;
     int i=0;
     for(i=0;i<10;i++){
diff --git a/mozilla/xpcom/ds/nsStr.cpp b/mozilla/xpcom/ds/nsStr.cpp
index 153e0240e69..528d321c2ee 100644
--- a/mozilla/xpcom/ds/nsStr.cpp
+++ b/mozilla/xpcom/ds/nsStr.cpp
@@ -65,7 +65,7 @@ public:
     memset(mPools,0,sizeof(mPools));
   }
 
-  ~nsPoolingMemoryAgent() {
+  virtual ~nsPoolingMemoryAgent() {
     nsBufferDeallocator theDeallocator;
     int i=0;
     for(i=0;i<10;i++){
diff --git a/mozilla/xpcom/io/nsByteBufferInputStream.cpp b/mozilla/xpcom/io/nsByteBufferInputStream.cpp
index 161015b1b01..acbef95e5aa 100644
--- a/mozilla/xpcom/io/nsByteBufferInputStream.cpp
+++ b/mozilla/xpcom/io/nsByteBufferInputStream.cpp
@@ -167,7 +167,7 @@ public:
     // nsDummyBufferStream methods:
     nsDummyBufferStream(const char* buffer, PRUint32 length)
         : mBuffer(buffer), mLength(length) {}
-    ~nsDummyBufferStream() {}
+    virtual ~nsDummyBufferStream() {}
 
 protected:
     const char* mBuffer;
diff --git a/mozilla/xpcom/string/obsolete/nsStr.cpp b/mozilla/xpcom/string/obsolete/nsStr.cpp
index 153e0240e69..528d321c2ee 100644
--- a/mozilla/xpcom/string/obsolete/nsStr.cpp
+++ b/mozilla/xpcom/string/obsolete/nsStr.cpp
@@ -65,7 +65,7 @@ public:
     memset(mPools,0,sizeof(mPools));
   }
 
-  ~nsPoolingMemoryAgent() {
+  virtual ~nsPoolingMemoryAgent() {
     nsBufferDeallocator theDeallocator;
     int i=0;
     for(i=0;i<10;i++){
diff --git a/mozilla/xpcom/tests/dynamic/TestDynamic.cpp b/mozilla/xpcom/tests/dynamic/TestDynamic.cpp
index 968ffd232ec..53e0a49596b 100644
--- a/mozilla/xpcom/tests/dynamic/TestDynamic.cpp
+++ b/mozilla/xpcom/tests/dynamic/TestDynamic.cpp
@@ -65,7 +65,7 @@ class TestDynamicFactory: public nsIFactory {
     PR_AtomicIncrement(&g_FactoryCount);
   }
 
-  ~TestDynamicFactory() {
+  virtual ~TestDynamicFactory() {
     PR_AtomicDecrement(&g_FactoryCount);
   }