All new elements except the last one initialized to NULL. Ideally, once parsing is complete, all elements should be non-NULL.

To safe-guard BitcodeReader, this patch adds null check for all access to these list.
Patch by Dinesh Dwivedi!

llvm-svn: 204920

1 files changed, 7 insertions, 7 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index ab0a1249f2d..f712d9db641 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -960,7 +960,7 @@ error_code BitcodeReader::ParseValueSymbolTable() {
       if (ConvertToString(Record, 1, ValueName))
         return Error(InvalidRecord);
       unsigned ValueID = Record[0];
-      if (ValueID >= ValueList.size())
+      if (ValueID >= ValueList.size() || !ValueList[ValueID])
         return Error(InvalidRecord);
       Value *V = ValueList[ValueID];
 
@@ -1027,7 +1027,7 @@ error_code BitcodeReader::ParseMetadata() {
       unsigned Size = Record.size();
       NamedMDNode *NMD = TheModule->getOrInsertNamedMetadata(Name);
       for (unsigned i = 0; i != Size; ++i) {
-        MDNode *MD = dyn_cast<MDNode>(MDValueList.getValueFwdRef(Record[i]));
+        MDNode *MD = dyn_cast_or_null<MDNode>(MDValueList.getValueFwdRef(Record[i]));
         if (MD == 0)
           return Error(InvalidRecord);
         NMD->addOperand(MD);
@@ -1109,7 +1109,7 @@ error_code BitcodeReader::ResolveGlobalAndAliasInits() {
       // Not ready to resolve this yet, it requires something later in the file.
       GlobalInits.push_back(GlobalInitWorklist.back());
     } else {
-      if (Constant *C = dyn_cast<Constant>(ValueList[ValID]))
+      if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
         GlobalInitWorklist.back().first->setInitializer(C);
       else
         return Error(ExpectedConstant);
@@ -1122,7 +1122,7 @@ error_code BitcodeReader::ResolveGlobalAndAliasInits() {
     if (ValID >= ValueList.size()) {
       AliasInits.push_back(AliasInitWorklist.back());
     } else {
-      if (Constant *C = dyn_cast<Constant>(ValueList[ValID]))
+      if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
         AliasInitWorklist.back().first->setAliasee(C);
       else
         return Error(ExpectedConstant);
@@ -1135,7 +1135,7 @@ error_code BitcodeReader::ResolveGlobalAndAliasInits() {
     if (ValID >= ValueList.size()) {
       FunctionPrefixes.push_back(FunctionPrefixWorklist.back());
     } else {
-      if (Constant *C = dyn_cast<Constant>(ValueList[ValID]))
+      if (Constant *C = dyn_cast_or_null<Constant>(ValueList[ValID]))
         FunctionPrefixWorklist.back().first->setPrefixData(C);
       else
         return Error(ExpectedConstant);
@@ -1195,7 +1195,7 @@ error_code BitcodeReader::ParseConstants() {
     case bitc::CST_CODE_SETTYPE:   // SETTYPE: [typeid]
       if (Record.empty())
         return Error(InvalidRecord);
-      if (Record[0] >= TypeList.size())
+      if (Record[0] >= TypeList.size() || !TypeList[Record[0]])
         return Error(InvalidRecord);
       CurTy = TypeList[Record[0]];
       continue;  // Skip the ValueList manipulation.
@@ -3039,7 +3039,7 @@ OutOfRecordLoop:
     if (A->getParent() == 0) {
       // We found at least one unresolved value.  Nuke them all to avoid leaks.
       for (unsigned i = ModuleValueListSize, e = ValueList.size(); i != e; ++i){
-        if ((A = dyn_cast<Argument>(ValueList[i])) && A->getParent() == 0) {
+        if ((A = dyn_cast_or_null<Argument>(ValueList[i])) && A->getParent() == 0) {
           A->replaceAllUsesWith(UndefValue::get(A->getType()));
           delete A;
         }