[cfe-dev] DWARF2_FRAME_REG_OUT

Jack Howarth howarth at bromo.med.uc.edu
Tue Feb 8 13:06:44 PST 2011


On Tue, Feb 08, 2011 at 11:27:21PM +0300, Anton Korobeynikov wrote:
> Hi Jack,
> 
> > is still present in config/i386/darwin.h for llvm-gcc42, but I can't find an analogous code in clang.
> > Does clang handle this issue differently than llvm-gcc42?
> No, clang handle this issue exactly the same way as llvm-gcc. The
> answer is simple: this part of code is for gcc backend, which is not
> used by llvm code at all.
> LLVM backend can have the arbitrary list of register numbers. Right
> now they are (on x86): "for 64 bit", "for 32 bit debug", "for 32 bit
> eh".

Anton,
   My understanding is that DWARF2_FRAME_REG_OUT existed on darwin 
because the register 4 (EBP) and register 5 (ESP) got swapped long ago
and that macro existed because the eh_frame register numbering and the
DWARF debug info registering numbering were different for those two.
Was this issue FSF gcc specific or in the standards themselves?
                  Jack

> 
> -- 
> With best regards, Anton Korobeynikov
> Faculty of Mathematics and Mechanics, Saint Petersburg State University



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