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* [Bug preprocessor/58379] New: default mmap based implementation (mmap_gt_pch_get_address/mmap_gt_pch_use_address) is useless @ 2013-09-10 10:19 martin at netbsd dot org 2013-09-10 11:32 ` [Bug preprocessor/58379] " rguenth at gcc dot gnu.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: martin at netbsd dot org @ 2013-09-10 10:19 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58379 Bug ID: 58379 Summary: default mmap based implementation (mmap_gt_pch_get_address/mmap_gt_pch_use_address) is useless Product: gcc Version: 4.8.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: preprocessor Assignee: unassigned at gcc dot gnu.org Reporter: martin at netbsd dot org I may be misunderstanding the interface - but it looks to me like it lets the kernel chose an arbitrary mapping address for different compiler invocations but relies on the assumption that the returned address will be the same. If not, the compiler fails with a fatal_error when trying to read a precompiled header file ("had to relocate PCH"). I can not imagine a host system where this would work reliably (or even typically twice in a row). Please tell me I misunderstood, or consider disabling PCH support for host platforms without host_hooks overriding this function. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug preprocessor/58379] default mmap based implementation (mmap_gt_pch_get_address/mmap_gt_pch_use_address) is useless 2013-09-10 10:19 [Bug preprocessor/58379] New: default mmap based implementation (mmap_gt_pch_get_address/mmap_gt_pch_use_address) is useless martin at netbsd dot org @ 2013-09-10 11:32 ` rguenth at gcc dot gnu.org 2013-09-10 13:13 ` martin at netbsd dot org 2021-12-08 18:21 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2013-09-10 11:32 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58379 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- Well, it doesn't _rely_ on it - it basically makes systems where that is the case work out of the box (every system pre address-space-randomization area). If you have a system that randomizes then you have to re-define the hook. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug preprocessor/58379] default mmap based implementation (mmap_gt_pch_get_address/mmap_gt_pch_use_address) is useless 2013-09-10 10:19 [Bug preprocessor/58379] New: default mmap based implementation (mmap_gt_pch_get_address/mmap_gt_pch_use_address) is useless martin at netbsd dot org 2013-09-10 11:32 ` [Bug preprocessor/58379] " rguenth at gcc dot gnu.org @ 2013-09-10 13:13 ` martin at netbsd dot org 2021-12-08 18:21 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: martin at netbsd dot org @ 2013-09-10 13:13 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58379 --- Comment #2 from Martin Husemann <martin at netbsd dot org> --- (In reply to Richard Biener from comment #1) > If you have a system that randomizes then you have to re-define the hook. Besides ASLR there are various things out of control of the compiler that do result in varying mapping adresses (like malloc using mmap instead of brk), so chances are low in any modern system. I'm not opposed to create a hook for NetBSD, but I have a hard time seeing a possible sensible implementation. Look at the #ifdef cascade in config/host-openbsd.c for a disgusting example of code that should not be in a compiler (IMHO). How hard is making the externalized format address neutral? ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug preprocessor/58379] default mmap based implementation (mmap_gt_pch_get_address/mmap_gt_pch_use_address) is useless 2013-09-10 10:19 [Bug preprocessor/58379] New: default mmap based implementation (mmap_gt_pch_get_address/mmap_gt_pch_use_address) is useless martin at netbsd dot org 2013-09-10 11:32 ` [Bug preprocessor/58379] " rguenth at gcc dot gnu.org 2013-09-10 13:13 ` martin at netbsd dot org @ 2021-12-08 18:21 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-12-08 18:21 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58379 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- See Also| |https://gcc.gnu.org/bugzill | |a/show_bug.cgi?id=71934 --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- I think this is getting fixed via PR 71934. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-12-08 18:21 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2013-09-10 10:19 [Bug preprocessor/58379] New: default mmap based implementation (mmap_gt_pch_get_address/mmap_gt_pch_use_address) is useless martin at netbsd dot org 2013-09-10 11:32 ` [Bug preprocessor/58379] " rguenth at gcc dot gnu.org 2013-09-10 13:13 ` martin at netbsd dot org 2021-12-08 18:21 ` pinskia at gcc dot gnu.org
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