Re: gcc corrections for better pie support

["Peter S. Mazinger" <ps dot m at gmx dot net>]

Hello!

I have updated the earlier sent patches to apply to 3.4.0 up to 3.4.3. 
These patches are in "production" on Gentoo since gcc-3.3.3
Read further what it does.

Consider applying, thanks Peter

On Mon, 10 May 2004, Peter S. Mazinger wrote:

> Hello!
> 
> The attached patches correct gcc's behaviour if some weird CFLAGS/LDFLAGS 
> are used. They only manipulate the created specs file.
> 
> The logic of the patch is as used by gcc in the specs link section:
> if shared is defined we are trying to build shlib, else if static is 
> defined, we try to build a static exec, else if pie is defined we build 
> ET_DYN, else old standard build.
> 
> The current implementation of the specs does not do that consistently.
> 
> What this patch corrects/offers:
> 
> 1. startfile/endfile usage problem
> If more then one of the flags shared/static/pie are used, we could end up 
> w/ 2 startfiles or endfiles, or use the false ones
> 
> 2. the link section tries to filter out some incompatible flags by using 
> %{<flag:} to not propagate them to the link_command (there are remaining 
> cases where this could happen)
> 
> 3. the cc1 options patch parts blocks some incompat flags, like using 
> -fPIE and -shared (the dyn lib will surely end up w/ TEXTREL, test-case 
> zlib <= 1.2.1.1) or -pg/-p/-profile along w/ -pie, useless unless we 
> have a profiling -pie compliant implementation of gcrt1.o
> 
> 4. correction of the HAVE_LD_PIE logic, if binutils' ld does not support 
> -pie, then pie is useless, so added ifdefs to endfile section too and 
> removed the usage of *S.o in startfile too.
> 
> 5. the link_command section should support pie propagation, but it should 
> allow adding -pie to ld only for the case when the startfile/endfile are 
> added, based on the current implementation it is 
> !A/!nostdlib/!nostartfiles(in link_command) and !static/!ibcs/!shared 
> (from link section) 
> This patch is not added to the currently sent tarball.
> 
> 6. some changes to archs are generic PIC modifications (like changing the 
> PIC support for arm and adding -pie). I do not have enough C knowledge 
> to make this correcty, and it needs some more changes to be correct for 
> all archs, sparc[64] needs a full rewrite of this part that I am not able 
> to do.
> My idea of this is to use flag_pic/builtin_define everywhere were possible 
> (cc1 section: instead of -fPIC|-fpic|-fPIE|-fpie and asm section: using -K 
> PIC or similar)
> 
> I would be grateful, if I would get an answer/reaction from you, knowing 
> that it will be considered for addition upstream or not.
> Please cc to me, I am not on any gcc list.
> 
> The patches should apply after 20040412 branch update.
> 
> Peter
> 
> 

-- 
Peter S. Mazinger <ps dot m at gmx dot net>           ID: 0xA5F059F2
Key fingerprint = 92A4 31E1 56BC 3D5A 2D08  BB6E C389 975E A5F0 59F2

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