Re: [libunwind] How does libunwind find the PFS, the return address and the alloc instruction?

[David Mosberger]

>>>>> On Mon, 08 Dec 2003 10:46:12 +0100, Johan Walles <address@hidden> said:

  Johan> When unwinding the stack on IA64, how does libunwind find the
  Johan> alloc instruction, the register in which the PFS is stored,
  Johan> and the register in which the return address is stored?

Based on the later mail, I think this part has been answered already.
The answer lies in the unwind info (whether static or dynamic).

  Johan> More specifically, regarding the dynamic unwinding, do I need
  Johan> to tell libunwind about these things, or does it figure them
  Johan> out by itself (by disassembling the function)?

It definitely does NOT disassemble the function.  Unwinding needs to
work reliably and code-reading can't really be reliable (unless you
place unreasonable restrictions on compilers/code-generators).  Also,
some code may be mapped with EXECUTE-ONLY privilege, so disassembling
may not even be possible (true for the Linux kernel's gate page, for
example).

        --david