Re: gcc conformance to HP-PA ABI

[hainque at ACT-Europe dot FR (Olivier Hainque)]

Thank you very much for your extensive comments :)

This one :

>    * The unwind table information being generated from the
>         compiler-generated .CALLINFO directives is incorrect:
>           (a) the SAVE_SP argument should not be set when the FP is
>               manifested in %r3.  It should only be set when the old
>               SP has been saved at -4 in the frame marker.  Normally,
>               only low-level assembler code does this.

Indeed explains the behavior I observed on a very simple example with
respect to using -fomit-frame-pointer or not.

> If PA-RISC gcc were changed to fix these issues (and I'm not saying that
> it should be changed), you would be able to use the HP unwind library with
> gcc generated code.  Even then, you would be restricted to unwinding only
> from the body of functions.  You would not be able to unwind from, say, a
> fault in prologue or epilogue code, which the HP unwind library allows.
> To support prologue and epilogue unwinding, the compiler would have to
> generate a highly stereotyped series of prologue and epilogue
> instructions.  HP's runtime architecture document doesn't document these,
> but instead invites readers to inspect how the HP assembler expands the
> .ENTER and .LEAVE directives. 
>               

Ok.


Thanks again for all the responses I got.

Olivier