[cfe-commits] [PATCH] Fixed SrcMgr::FileInfo pointer magic issue in getContentCache()

[Matthieu Monrocq]

On Tue, Nov 13, 2012 at 9:47 AM, Riku Palomäki <riku at multitouch.fi> wrote:

> Hi,
>
> uintptr_t SrcMgr::FileInfo::Data is used to store both a pointer value
> and some additional flags. getContentCache-function tries to get only
> the raw pointer value from Data, but fails to do so since it uses
> wrong size int. At least on Windows 8 with 64-bit Visual Studio 2012
> this function always returns corrupted pointers.
>
> On some platforms unsigned long long would be actually too large for
> this use. If this triggers a warning on gcc, maybe it should be
> written like ~uintptr_t(7UL).
>
> Btw, why on earth would you like to store pointers and additional
> flags to the same variable, ran out of bits?
>
> --
> Riku Palomäki
> MultiTouch
>
>
The LLVM and Clang compilers are highly optimized for speed and low-memory
consumption, so classes that tend to be instantiated "en masse" often
contain either bit fields or pack bits into the pointers.

I would suggest using ~uintptr_t, just to be on the safe side, however I am
unsure about the suffix of the literal in this case. I believe no suffix at
all would be safe given the cast.

-- Matthieu
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