[cfe-commits] r46859 - in /cfe/trunk: CodeGen/CGExpr.cpp CodeGen/CodeGenTypes.cpp test/CodeGen/bitfield.c

[Chris Lattner]

I think we also need alignment info in there, Duncan did you recently  
run into this in llvm-gcc?

-Chris

On Feb 8, 2008, at 7:15 PM, Eli Friedman wrote:

> On Feb 8, 2008 12:02 PM, Lauro Ramos Venancio <lauro.venancio at gmail.com 
> > wrote:
>> Nowadays, I think we should change the placeBitfield function
>> (CodeGenType.cpp) to provide more information making easier to
>> implement bitfield initializer.
>
> Okay.  Ideally, what I would need is, for every declared field in a
> bitfield, something like the following:
>
> struct BitFieldPiece {
>  unsigned LLVMFieldNo;
>  unsigned StartBit;
>  unsigned EndBit;
> }
> typedef std::vector<BitFieldPiece> BitFieldLayoutData;
>
> This data makes the initializers relatively easy to implement, and
> avoids any dependency on platform-specific bitfield layout rules, no
> matter how strange they are. (I don't know how strange the rules can
> get, though, so I'm not sure if this much generality is needed.)
>
> -Eli
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