Update Clang to change in ReadAbbrevBlock API (bug 20485)

[david2050]

Summary

Modified ReadAbbrevBlock to return "true' when an error is identified (instead of crashing). Propagate that error appropriately

[filcab]

Hi David,

Can you make a test for this? At the very least the "malformed abbrev record in AST file" branch.

[• rafael]

lib/Serialization/ASTReader.cpp

1344

This should not be needed. The idea of having a diagnostic handler is that the diagnostic has to be issued only once. With this clang would be printing two errors.This one and one from the bitcode reader.

[david2050]

simple change already committed to LLVM

lib/Frontend/SerializedDiagnosticReader.cpp

case llvm::bitc::ENTER_SUBBLOCK:
       return Cursor::BlockBegin;
 
     case llvm::bitc::END_BLOCK:
       if (Stream.ReadBlockEnd())
         return SDError::InvalidDiagnostics;
       return Cursor::BlockEnd;
 
     case llvm::bitc::DEFINE_ABBREV:
-      Stream.ReadAbbrevRecord();
+      if (Stream.ReadAbbrevRecord()) 
+        return SDError::InvalidDiagnostics;
       continue;
 
     case llvm::bitc::UNABBREV_RECORD:
       return SDError::UnsupportedConstruct;
 
     default:
       // We found a record.
       BlockOrRecordID = Code;

lib/Serialization/ASTReader.cpp

while (true) {
     uint64_t Offset = Cursor.GetCurrentBitNo();
     unsigned Code = Cursor.ReadCode();
 
     // We expect all abbrevs to be at the start of the block.
     if (Code != llvm::bitc::DEFINE_ABBREV) {
       Cursor.JumpToBit(Offset);
       return false;
     }
-    Cursor.ReadAbbrevRecord();
+    if (Cursor.ReadAbbrevRecord()) {
+      Error("malformed abbrev record in AST file");
+      return Failure;
+    }
   }
 }
 
 Token ASTReader::ReadToken(ModuleFile &F, const RecordDataImpl &Record,
                            unsigned &Idx) {
   Token Tok;
   Tok.startToken();
   Tok.setLocation(ReadSourceLocation(F, Record, Idx));
while (true) {
       uint64_t Offset = InputFilesCursor.GetCurrentBitNo();
       unsigned Code = InputFilesCursor.ReadCode();
 
       // We expect all abbrevs to be at the start of the block.
       if (Code != llvm::bitc::DEFINE_ABBREV) {
         InputFilesCursor.JumpToBit(Offset);
         break;
       }
-      InputFilesCursor.ReadAbbrevRecord();
+      if (InputFilesCursor.ReadAbbrevRecord())
+        return true;
     }
   }
   
   // Scan for ORIGINAL_FILE inside the control block.
   RecordData Record;
   std::string ModuleDir;
   while (1) {
     llvm::BitstreamEntry Entry = Stream.advanceSkippingSubblocks();