[llvm] r237614 - [YAML] Plug a memory leak

[Benjamin Kramer]

On Mon, May 18, 2015 at 11:22 PM, David Blaikie <dblaikie at gmail.com> wrote:
>
>
> On Mon, May 18, 2015 at 2:11 PM, Benjamin Kramer <benny.kra at googlemail.com>
> wrote:
>>
>> Author: d0k
>> Date: Mon May 18 16:11:27 2015
>> New Revision: 237614
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=237614&view=rev
>> Log:
>> [YAML] Plug a memory leak
>>
>> The destructor of BlockScalarNode is never called. Store the contained
>> string in BumpPtrAllocated memory instead.
>
>
> Reckon we could put a static_assert in BumpPtrAllocator that checks that
> objects allocated with it have trivial destruction? I suppose that'd work in
> SpecificBumpPtrAllocator - but maybe we could template the allocate
> operation of the non-specificBumpPtrAllocator to catch them there too...

There are places in LLVM that use a BumpPtrAllocator and call the
destructor manually (crazy, isn't it?). Also global 'operator new'
overloads don't have any type information, so adding type trait checks
would require massive code churn :(

- Ben

>>
>>
>> Modified:
>>     llvm/trunk/include/llvm/Support/YAMLParser.h
>>     llvm/trunk/lib/Support/YAMLParser.cpp
>>
>> Modified: llvm/trunk/include/llvm/Support/YAMLParser.h
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/YAMLParser.h?rev=237614&r1=237613&r2=237614&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/include/llvm/Support/YAMLParser.h (original)
>> +++ llvm/trunk/include/llvm/Support/YAMLParser.h Mon May 18 16:11:27 2015
>> @@ -235,8 +235,8 @@ class BlockScalarNode : public Node {
>>
>>  public:
>>    BlockScalarNode(std::unique_ptr<Document> &D, StringRef Anchor,
>> StringRef Tag,
>> -                  std::string &Value, StringRef RawVal)
>> -      : Node(NK_BlockScalar, D, Anchor, Tag), Value(std::move(Value)) {
>> +                  StringRef Value, StringRef RawVal)
>> +      : Node(NK_BlockScalar, D, Anchor, Tag), Value(Value) {
>>      SMLoc Start = SMLoc::getFromPointer(RawVal.begin());
>>      SMLoc End = SMLoc::getFromPointer(RawVal.end());
>>      SourceRange = SMRange(Start, End);
>> @@ -250,7 +250,7 @@ public:
>>    }
>>
>>  private:
>> -  std::string Value;
>> +  StringRef Value;
>>  };
>>
>>  /// \brief A key and value pair. While not technically a Node under the
>> YAML
>>
>> Modified: llvm/trunk/lib/Support/YAMLParser.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/YAMLParser.cpp?rev=237614&r1=237613&r2=237614&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/Support/YAMLParser.cpp (original)
>> +++ llvm/trunk/lib/Support/YAMLParser.cpp Mon May 18 16:11:27 2015
>> @@ -2377,11 +2377,13 @@ parse_property:
>>                  , AnchorInfo.Range.substr(1)
>>                  , TagInfo.Range
>>                  , T.Range);
>> -  case Token::TK_BlockScalar:
>> +  case Token::TK_BlockScalar: {
>>      getNext();
>> +    StringRef StrCopy = StringRef(T.Value).copy(NodeAllocator);
>>      return new (NodeAllocator)
>>          BlockScalarNode(stream.CurrentDoc, AnchorInfo.Range.substr(1),
>> -                        TagInfo.Range, T.Value, T.Range);
>> +                        TagInfo.Range, StrCopy, T.Range);
>> +  }
>>    case Token::TK_Key:
>>      // Don't eat the TK_Key, KeyValueNode expects it.
>>      return new (NodeAllocator)
>>
>>
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>
>