BUG#31761: Code for cluster is not safe for strict-alias optimization in new gcc

Fix problem with AttributeHeader::init() seen with gcc 4.2.1.

Using the same object as both Uint32 and class AttributeHeader violates
strict aliasing rule.

ndb/include/kernel/AttributeHeader.hpp

@@ -42,8 +42,7 @@ public:
   STATIC_CONST( FRAGMENT_MEMORY= 0xFFF9 );
 
   /** Initialize AttributeHeader at location aHeaderPtr */
-  static AttributeHeader& init(void* aHeaderPtr, Uint32 anAttributeId, 
-			       Uint32 aDataSize);
+  static void init(Uint32* aHeaderPtr, Uint32 anAttributeId, Uint32 aDataSize);
 
   /** Returns size of AttributeHeader (usually one or two words) */
   Uint32 getHeaderSize() const; // In 32-bit words
@@ -101,10 +100,11 @@ public:
  */
 
 inline
-AttributeHeader& AttributeHeader::init(void* aHeaderPtr, Uint32 anAttributeId, 
-				       Uint32 aDataSize)
+void AttributeHeader::init(Uint32* aHeaderPtr, Uint32 anAttributeId, 
+                           Uint32 aDataSize)
 {
-  return * new (aHeaderPtr) AttributeHeader(anAttributeId, aDataSize);
+  AttributeHeader ah(anAttributeId, aDataSize);
+  *aHeaderPtr = ah.m_value;
 }
 
 inline

ndb/src/kernel/blocks/dbtup/DbtupExecQuery.cpp

@@ -1578,8 +1578,8 @@ int Dbtup::interpreterNextLab(Signal* signal,
 	  Uint32 TdataForUpdate[3];
 	  Uint32 Tlen;
 
-	  AttributeHeader& ah = AttributeHeader::init(&TdataForUpdate[0], 
-						      TattrId, TattrNoOfWords);
+	  AttributeHeader ah(TattrId, TattrNoOfWords);
+          TdataForUpdate[0] = ah.m_value;
 	  TdataForUpdate[1] = TregMemBuffer[theRegister + 2];
 	  TdataForUpdate[2] = TregMemBuffer[theRegister + 3];
 	  Tlen = TattrNoOfWords + 1;
@@ -1595,6 +1595,7 @@ int Dbtup::interpreterNextLab(Signal* signal,
 		// Write a NULL value into the attribute
 		/* --------------------------------------------------------- */
 		ah.setNULL();
+                TdataForUpdate[0] = ah.m_value;
 		Tlen = 1;
 	      }//if
 	      int TnoDataRW= updateAttributes(pagePtr,

ndb/src/kernel/blocks/dbtup/DbtupRoutines.cpp

@@ -677,8 +677,6 @@ bool
 Dbtup::checkUpdateOfPrimaryKey(Uint32* updateBuffer, Tablerec* const regTabPtr)
 {
   Uint32 keyReadBuffer[MAX_KEY_SIZE_IN_WORDS];
-  Uint32 attributeHeader;
-  AttributeHeader* ahOut = (AttributeHeader*)&attributeHeader;
   AttributeHeader ahIn(*updateBuffer);
   Uint32 attributeId = ahIn.getAttributeId();
   Uint32 attrDescriptorIndex = regTabPtr->tabDescriptor + (attributeId << ZAD_LOG_SIZE);
@@ -701,16 +699,17 @@ Dbtup::checkUpdateOfPrimaryKey(Uint32* updateBuffer, Tablerec* const regTabPtr)
 
   ReadFunction f = regTabPtr->readFunctionArray[attributeId];
 
-  AttributeHeader::init(&attributeHeader, attributeId, 0);
+  AttributeHeader attributeHeader(attributeId, 0);
   tOutBufIndex = 0;
   tMaxRead = MAX_KEY_SIZE_IN_WORDS;
 
   bool tmp = tXfrmFlag;
   tXfrmFlag = true;
-  ndbrequire((this->*f)(&keyReadBuffer[0], ahOut, attrDescriptor, attributeOffset));
+  ndbrequire((this->*f)(&keyReadBuffer[0], &attributeHeader, attrDescriptor,
+                        attributeOffset));
   tXfrmFlag = tmp;
-  ndbrequire(tOutBufIndex == ahOut->getDataSize());
-  if (ahIn.getDataSize() != ahOut->getDataSize()) {
+  ndbrequire(tOutBufIndex == attributeHeader.getDataSize());
+  if (ahIn.getDataSize() != attributeHeader.getDataSize()) {
     ljam();
     return true;
   }//if

ndb/src/kernel/blocks/dbutil/DbUtil.cpp

@@ -1169,9 +1169,7 @@ DbUtil::prepareOperation(Signal* signal, PreparePtr prepPtr)
     /**************************************************************
      * Attribute found - store in mapping  (AttributeId, Position)
      **************************************************************/
-    AttributeHeader & attrMap = 
-      AttributeHeader::init(attrMappingIt.data, 
-			    attrDesc.AttributeId,    // 1. Store AttrId
+    AttributeHeader attrMap(attrDesc.AttributeId,    // 1. Store AttrId
 			    0);
     
     if (attrDesc.AttributeKeyFlag) {
@@ -1200,6 +1198,7 @@ DbUtil::prepareOperation(Signal* signal, PreparePtr prepPtr)
 	return;
       }
     }
+    *(attrMappingIt.data) = attrMap.m_value;
 #if 0
     ndbout << "BEFORE: attrLength: " << attrLength << endl;
 #endif

ndb/src/ndbapi/NdbOperationDefine.cpp

@@ -363,9 +363,8 @@ NdbOperation::getValue_impl(const NdbColumnImpl* tAttrInfo, char* aValue)
 	return NULL;
       }//if
     }//if
-    Uint32 ah;
-    AttributeHeader::init(&ah, tAttrInfo->m_attrId, 0);
-    if (insertATTRINFO(ah) != -1) {	
+    AttributeHeader ah(tAttrInfo->m_attrId, 0);
+    if (insertATTRINFO(ah.m_value) != -1) {	
       // Insert Attribute Id into ATTRINFO part. 
       
       /************************************************************************
@@ -496,12 +495,11 @@ NdbOperation::setValue( const NdbColumnImpl* tAttrInfo,
   
   tAttrId = tAttrInfo->m_attrId;
   const char *aValue = aValuePassed; 
-  Uint32 ahValue;
   if (aValue == NULL) {
     if (tAttrInfo->m_nullable) {
-      AttributeHeader& ah = AttributeHeader::init(&ahValue, tAttrId, 0);
+      AttributeHeader ah(tAttrId, 0);
       ah.setNULL();
-      insertATTRINFO(ahValue);
+      insertATTRINFO(ah.m_value);
       // Insert Attribute Id with the value
       // NULL into ATTRINFO part. 
       DBUG_RETURN(0);
@@ -534,9 +532,8 @@ NdbOperation::setValue( const NdbColumnImpl* tAttrInfo,
   }//if
   const Uint32 totalSizeInWords = (sizeInBytes + 3)/4; // Including bits in last word
   const Uint32 sizeInWords = sizeInBytes / 4;          // Excluding bits in last word
-  AttributeHeader& ah = AttributeHeader::init(&ahValue, tAttrId, 
-					      totalSizeInWords);
-  insertATTRINFO( ahValue );
+  AttributeHeader ah(tAttrId, totalSizeInWords);
+  insertATTRINFO( ah.m_value );
 
   /***********************************************************************
    * Check if the pointer of the value passed is aligned on a 4 byte boundary.