[PATCH] Inconsistency in Preprocessor::ReleaseMacroInfo(MacroInfo *MI)

[Yaron Keren]

Hi Vassil,

Do you mean double destruction (not deletion) of MacroInfo first time in
ReleaseMacroInfo and the second time in ~Preprocessor via  ~MacroInfoChain?

  while (MacroInfoChain *I = MIChainHead) {
    MIChainHead = I->Next;
    I->~MacroInfoChain();
  }

or something else?

Yaron



2014-08-02 23:05 GMT+03:00 Vassil Vassilev <vvasilev at cern.ch>:

> Hi,
>   In cases where ReleaseMacroInfo gets called and it doesn't cleanup the
> Preprocessor's MIChainHead can lead to double deletion. I am sending the
> patch that fixes the problem for me.
> Vassil
>
>
> diff --git a/lib/Lex/PPDirectives.cpp b/lib/Lex/PPDirectives.cpp
> index 5f38387..1a9b5eb 100644
> --- a/lib/Lex/PPDirectives.cpp
> +++ b/lib/Lex/PPDirectives.cpp
> @@ -94,6 +94,14 @@ Preprocessor::AllocateVisibilityMacroDirective(SourceLocation
> Loc,
>  /// error in the macro definition.
>  void Preprocessor::ReleaseMacroInfo(MacroInfo *MI) {
>    // Don't try to reuse the storage; this only happens on error paths.
> +
> +  // If this is on the macro info chain, avoid double deletion on
> teardown.
> +  while (MacroInfoChain *I = MIChainHead) {
> +    if (&(I->MI) == MI)
> +      I->Next = (I->Next) ? I->Next->Next : 0;
> +    MIChainHead = I->Next;
> +  }
> +
>    MI->~MacroInfo();
>  }
>
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