From: jont@harlequin.co.uk (Jon Thackray) Subject: Re: Section attributes from ld 16 Jul 1997 08:33:19 -0700 Approved: cygnus.gnu-win32@cygnus.com Distribution: cygnus Message-ID: <199707161317.OAA27491.cygnus.gnu-win32@zaphod.long.harlequin.co.uk> References: <199707151105.MAA14711@zaphod.long.harlequin.co.uk> <199707152216.SAA07402@tweedledumb.cygnus.com> <199707161156.MAA27248@zaphod.long.harlequin.co.uk> Original-To: ian@cygnus.com, gnu-win32@cygnus.com In-Reply-To: <199707161156.MAA27248@zaphod.long.harlequin.co.uk> Original-Sender: owner-gnu-win32@cygnus.com Jon Thackray writes: > ian@cygnus.com writes: > > >How does ld determine which attributes sections are to have? By > > >attributes, I mean things like:- > > > > >Contains code, contains initialised data, should be laoded with > > >execute permission, should be loaded with read permission, should be > > >loaded with write permission etc. > > > > The attributes are based on the attributes of the input sections which > > are mapped into the output sections. Take a look at > > gas/config/obj-coff.c to see how to use the .section directive in an > > assembler file. > > As far as I can see, this allows me no control over the flags I'm > talking about. The ones I mean are documented in MSDN as:- > > IMAGE_SCN_MEM_DISCARDABLE 0x02000000 > IMAGE_SCN_MEM_NOT_CACHED 0x04000000 > IMAGE_SCN_MEM_NOT_PAGED 0x08000000 > IMAGE_SCN_MEM_SHARED 0x10000000 > IMAGE_SCN_MEM_EXECUTE 0x20000000 > IMAGE_SCN_MEM_READ 0x40000000 > IMAGE_SCN_MEM_WRITE 0x80000000 > > It would appear that as automatcially puts MEM_READ and MEM_EXECUTE on > the .text section, MEM_READ and MEM_WRITE on the .data section and the > same on the .bss section. For sections it doesn't know about (eg I > have one called .dyfix), it outs none of these. However, my compiler, > when generating these sections, does add attributes such as MEM_READ > and MEM_WRITE, but then ld appears to throw them away (at least binary > editing the resulting executable or looking at it with any of the > tools available shows them to have gone away). As an experiment, I made an object file without the MEM_EXECUTE flag for the .text section, and then linked it (with nothing else at all). ld put the MEM_EXECUTE flag back on the .text section, which suggests that the attributes aren't entirely based on those incoming. - For help on using this list (especially unsubscribing), send a message to "gnu-win32-request@cygnus.com" with one line of text: "help".