topic Re: i64 image unwind info duplication? in Operating System - OpenVMS

i64 image unwind info duplication?

Douglas Rupp — Mon, 12 Mar 2007 21:36:06 GMT

Given a null C program test1.c: main(){;}, which is compiled and linked cc test1, link/map/full test1.

The map file shows a program segment #1 with [UNWIND] info and a segment #3 of type DYNAMIC.

anal/image/seg=num=1 test1.exe gives only a raw data dump, with no indication that its unwind info.

anal/image/seg=num=3 dumps, among other things, some unwind info, nicely translated that looks like it might be a duplication of what's in segment #1.

Why the (apparent) duplication of data?

Re: i64 image unwind info duplication?

John Gillings — Tue, 13 Mar 2007 16:12:32 GMT

Douglas,

Maybe you need to show an example of the apparent duplication?

Just a guess, perhaps one is static and the other (as labelled?) dynamic. The static copy may be required to reset the dynamic copy (though I'm having trouble thinking up circumstances under which it might need resetting, but then Itaniums are strange beasts).

Re: i64 image unwind info duplication?

Douglas Rupp — Tue, 13 Mar 2007 16:23:27 GMT

I received a private email from an HP engineer. The answer is the dynamic segment contains some info that allows analyze to interpret the info contained in segment #1. So the same info gets dumped twice, once in order in raw format and later, out of order, in interpreted format.