* [Buildroot] [PATCH 1/1] gcc: Support configure option --with-linker-hash-style @ 2017-12-15 23:25 Stefan Fröberg 2017-12-15 23:27 ` [Buildroot] FW: " Kees van Unen 2017-12-16 15:23 ` [Buildroot] " Thomas Petazzoni 0 siblings, 2 replies; 10+ messages in thread From: Stefan Fröberg @ 2017-12-15 23:25 UTC (permalink / raw) To: buildroot This will set the default hash style that GCC will always use during linking. Signed-off-by: Stefan Fr?berg <stefan.froberg@petroprogram.com> --- package/gcc/Config.in.host | 27 +++++++++++++++++++++++++++ package/gcc/gcc.mk | 12 ++++++++++++ 2 files changed, 39 insertions(+) diff --git a/package/gcc/Config.in.host b/package/gcc/Config.in.host index 70cce0a5c5..b9391392e1 100644 --- a/package/gcc/Config.in.host +++ b/package/gcc/Config.in.host @@ -152,3 +152,30 @@ config BR2_GCC_ENABLE_GRAPHITE comment "graphite support needs gcc >= 5.x" depends on !BR2_TOOLCHAIN_GCC_AT_LEAST_5 + +choice + prompt "Hash style used during linking" + default BR2_GCC_HASH_STYLE_GNU + help + This tells GCC to pass --hash-style=choice option to the + linker for all final links where choice can be one of + "gnu", "sysv" or "both". + Using "gnu" should give best application startup time. + +config BR2_GCC_HASH_STYLE_GNU + bool "gnu" + help + For new style GNU ".gnu.hash" section. + +config BR2_GCC_HASH_STYLE_SYSV + bool "sysv" + help + For classic ELF ".hash" section. + +config BR2_GCC_HASH_STYLE_BOTH + bool "both" + help + For both the classic ELF ".hash" and + new style GNU ".gnu.hash". + +endchoice diff --git a/package/gcc/gcc.mk b/package/gcc/gcc.mk index 27fc1e987c..51bb22d0e9 100644 --- a/package/gcc/gcc.mk +++ b/package/gcc/gcc.mk @@ -183,6 +183,18 @@ else HOST_GCC_COMMON_CONF_OPTS += --without-isl --without-cloog endif +ifeq ((BR2_GCC_HASH_STYLE_GNU),y) +HOST_GCC_COMMON_CONF_OPTS += --with-linker-hash-style=gnu +endif + +ifeq ((BR2_GCC_HASH_STYLE_SYSV),y) +HOST_GCC_COMMON_CONF_OPTS += --with-linker-hash-style=sysv +endif + +ifeq ((BR2_GCC_HASH_STYLE_BOTH),y) +HOST_GCC_COMMON_CONF_OPTS += --with-linker-hash-style=both +endif + ifeq ($(BR2_arc)$(BR2_or1k),y) HOST_GCC_COMMON_DEPENDENCIES += host-flex host-bison endif -- 2.13.6 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [Buildroot] FW: [PATCH 1/1] gcc: Support configure option --with-linker-hash-style 2017-12-15 23:25 [Buildroot] [PATCH 1/1] gcc: Support configure option --with-linker-hash-style Stefan Fröberg @ 2017-12-15 23:27 ` Kees van Unen 2017-12-16 1:50 ` Carlos Santos 2017-12-16 15:23 ` [Buildroot] " Thomas Petazzoni 1 sibling, 1 reply; 10+ messages in thread From: Kees van Unen @ 2017-12-15 23:27 UTC (permalink / raw) To: buildroot ________________________________________ Van: buildrootNamensStefan Fr?berg Verzonden: zaterdag 16 december 2017 00:25:30 (UTC+01:00) Amsterdam, Berlijn, Bern, Rome, Stockholm, Wenen Aan: buildroot at buildroot.org CC: thomas.petazzoni at free-electrons.com; Stefan Fr?berg Onderwerp: [Buildroot] [PATCH 1/1] gcc: Support configure option --with-linker-hash-style This will set the default hash style that GCC will always use during linking. Signed-off-by: Stefan Fr?berg <stefan.froberg@petroprogram.com> --- package/gcc/Config.in.host | 27 +++++++++++++++++++++++++++ package/gcc/gcc.mk | 12 ++++++++++++ 2 files changed, 39 insertions(+) diff --git a/package/gcc/Config.in.host b/package/gcc/Config.in.host index 70cce0a5c5..b9391392e1 100644 --- a/package/gcc/Config.in.host +++ b/package/gcc/Config.in.host @@ -152,3 +152,30 @@ config BR2_GCC_ENABLE_GRAPHITE comment "graphite support needs gcc >= 5.x" depends on !BR2_TOOLCHAIN_GCC_AT_LEAST_5 + +choice + prompt "Hash style used during linking" + default BR2_GCC_HASH_STYLE_GNU + help + This tells GCC to pass --hash-style=choice option to the + linker for all final links where choice can be one of + "gnu", "sysv" or "both". + Using "gnu" should give best application startup time. + +config BR2_GCC_HASH_STYLE_GNU + bool "gnu" + help + For new style GNU ".gnu.hash" section. + +config BR2_GCC_HASH_STYLE_SYSV + bool "sysv" + help + For classic ELF ".hash" section. + +config BR2_GCC_HASH_STYLE_BOTH + bool "both" + help + For both the classic ELF ".hash" and + new style GNU ".gnu.hash". + +endchoice diff --git a/package/gcc/gcc.mk b/package/gcc/gcc.mk index 27fc1e987c..51bb22d0e9 100644 --- a/package/gcc/gcc.mk +++ b/package/gcc/gcc.mk @@ -183,6 +183,18 @@ else HOST_GCC_COMMON_CONF_OPTS += --without-isl --without-cloog endif +ifeq ((BR2_GCC_HASH_STYLE_GNU),y) +HOST_GCC_COMMON_CONF_OPTS += --with-linker-hash-style=gnu +endif + +ifeq ((BR2_GCC_HASH_STYLE_SYSV),y) +HOST_GCC_COMMON_CONF_OPTS += --with-linker-hash-style=sysv +endif + +ifeq ((BR2_GCC_HASH_STYLE_BOTH),y) +HOST_GCC_COMMON_CONF_OPTS += --with-linker-hash-style=both +endif + ifeq ($(BR2_arc)$(BR2_or1k),y) HOST_GCC_COMMON_DEPENDENCIES += host-flex host-bison endif -- 2.13.6 _______________________________________________ buildroot mailing list buildroot at busybox.net http://lists.busybox.net/mailman/listinfo/buildroot ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [Buildroot] FW: [PATCH 1/1] gcc: Support configure option --with-linker-hash-style 2017-12-15 23:27 ` [Buildroot] FW: " Kees van Unen @ 2017-12-16 1:50 ` Carlos Santos 2017-12-16 1:51 ` [Buildroot] FW: " Kees van Unen 2017-12-16 12:11 ` [Buildroot] " Thomas Petazzoni 0 siblings, 2 replies; 10+ messages in thread From: Carlos Santos @ 2017-12-16 1:50 UTC (permalink / raw) To: buildroot ----- Original Message ----- > From: "Kees van Unen" <keesvanunen@hotmail.com> > To: buildroot at buildroot.org > Sent: Friday, December 15, 2017 9:27:57 PM > Subject: [Buildroot] FW: [PATCH 1/1] gcc: Support configure option --with-linker-hash-style > ________________________________________ > Van: buildrootNamensStefan Fr?berg > Verzonden: zaterdag 16 december 2017 00:25:30 (UTC+01:00) Amsterdam, Berlijn, > Bern, Rome, Stockholm, Wenen > Aan: buildroot at buildroot.org > CC: thomas.petazzoni at free-electrons.com; Stefan Fr?berg > Onderwerp: [Buildroot] [PATCH 1/1] gcc: Support configure option > --with-linker-hash-style [...] Why the hell are these messages being sent to the list? Isn't it possible to block them? -- Carlos Santos (Casantos) - DATACOM, P&D ?The greatest triumph that modern PR can offer is the transcendent success of having your words and actions judged by your reputation, rather than the other way about.? ? Christopher Hitchens ^ permalink raw reply [flat|nested] 10+ messages in thread
* [Buildroot] FW: FW: [PATCH 1/1] gcc: Support configure option --with-linker-hash-style 2017-12-16 1:50 ` Carlos Santos @ 2017-12-16 1:51 ` Kees van Unen 2017-12-16 12:11 ` [Buildroot] " Thomas Petazzoni 1 sibling, 0 replies; 10+ messages in thread From: Kees van Unen @ 2017-12-16 1:51 UTC (permalink / raw) To: buildroot ________________________________________ Van: buildrootNamensCarlos Santos Verzonden: zaterdag 16 december 2017 02:50:36 (UTC+01:00) Amsterdam, Berlijn, Bern, Rome, Stockholm, Wenen Aan: buildroot at buildroot.org Onderwerp: Re: [Buildroot] FW: [PATCH 1/1] gcc: Support configure option --with-linker-hash-style ----- Original Message ----- > From: "Kees van Unen" <keesvanunen@hotmail.com> > To: buildroot at buildroot.org > Sent: Friday, December 15, 2017 9:27:57 PM > Subject: [Buildroot] FW: [PATCH 1/1] gcc: Support configure option --with-linker-hash-style > ________________________________________ > Van: buildrootNamensStefan Fr?berg > Verzonden: zaterdag 16 december 2017 00:25:30 (UTC+01:00) Amsterdam, Berlijn, > Bern, Rome, Stockholm, Wenen > Aan: buildroot at buildroot.org > CC: thomas.petazzoni at free-electrons.com; Stefan Fr?berg > Onderwerp: [Buildroot] [PATCH 1/1] gcc: Support configure option > --with-linker-hash-style [...] Why the hell are these messages being sent to the list? Isn't it possible to block them? -- Carlos Santos (Casantos) - DATACOM, P&D ?The greatest triumph that modern PR can offer is the transcendent success of having your words and actions judged by your reputation, rather than the other way about.? ? Christopher Hitchens _______________________________________________ buildroot mailing list buildroot at busybox.net http://lists.busybox.net/mailman/listinfo/buildroot ^ permalink raw reply [flat|nested] 10+ messages in thread
* [Buildroot] FW: [PATCH 1/1] gcc: Support configure option --with-linker-hash-style 2017-12-16 1:50 ` Carlos Santos 2017-12-16 1:51 ` [Buildroot] FW: " Kees van Unen @ 2017-12-16 12:11 ` Thomas Petazzoni 1 sibling, 0 replies; 10+ messages in thread From: Thomas Petazzoni @ 2017-12-16 12:11 UTC (permalink / raw) To: buildroot Hello, On Fri, 15 Dec 2017 23:50:36 -0200 (BRST), Carlos Santos wrote: > Why the hell are these messages being sent to the list? > > Isn't it possible to block them? I've removed this person from the list of subscribers. Unless he resubscribes, that should be enough to stop the messages. Best regards, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com ^ permalink raw reply [flat|nested] 10+ messages in thread
* [Buildroot] [PATCH 1/1] gcc: Support configure option --with-linker-hash-style 2017-12-15 23:25 [Buildroot] [PATCH 1/1] gcc: Support configure option --with-linker-hash-style Stefan Fröberg 2017-12-15 23:27 ` [Buildroot] FW: " Kees van Unen @ 2017-12-16 15:23 ` Thomas Petazzoni 2017-12-17 14:30 ` Stefan Fröberg 1 sibling, 1 reply; 10+ messages in thread From: Thomas Petazzoni @ 2017-12-16 15:23 UTC (permalink / raw) To: buildroot Hello, On Sat, 16 Dec 2017 01:25:30 +0200, Stefan Fr?berg wrote: > This will set the default hash style that GCC will > always use during linking. > > Signed-off-by: Stefan Fr?berg <stefan.froberg@petroprogram.com> Could you explain the motivation for configuring the default hash style? If "gnu" gives the best application startup time, why would we use a different one? Generally, the commit log lacks a bit of background, i.e the "why" we would want such a change. Thanks! Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com ^ permalink raw reply [flat|nested] 10+ messages in thread
* [Buildroot] [PATCH 1/1] gcc: Support configure option --with-linker-hash-style 2017-12-16 15:23 ` [Buildroot] " Thomas Petazzoni @ 2017-12-17 14:30 ` Stefan Fröberg 2018-11-08 23:49 ` Romain Naour 0 siblings, 1 reply; 10+ messages in thread From: Stefan Fröberg @ 2017-12-17 14:30 UTC (permalink / raw) To: buildroot Hi Thomas Well, I was just worried that if setting the linking hash style to stone (aka "gnu") then could it maybe break builds in some other archs than x86, x86_64 and ARM ? So I played carefull and made it configurable by choice. Im not sure but I think that option has been hiding in GCC since 4.x and buildroot lowest is 4.9. So if it's okay I can cook another patch where it just set's it in stone without choice ? -S- Thomas Petazzoni kirjoitti 16.12.2017 klo 17:23: > Hello, > > On Sat, 16 Dec 2017 01:25:30 +0200, Stefan Fr?berg wrote: >> This will set the default hash style that GCC will >> always use during linking. >> >> Signed-off-by: Stefan Fr?berg <stefan.froberg@petroprogram.com> > Could you explain the motivation for configuring the default hash > style? If "gnu" gives the best application startup time, why would we > use a different one? > > Generally, the commit log lacks a bit of background, i.e the "why" we > would want such a change. > > Thanks! > > Thomas ^ permalink raw reply [flat|nested] 10+ messages in thread
* [Buildroot] [PATCH 1/1] gcc: Support configure option --with-linker-hash-style 2017-12-17 14:30 ` Stefan Fröberg @ 2018-11-08 23:49 ` Romain Naour 2018-11-09 21:35 ` Arnout Vandecappelle 0 siblings, 1 reply; 10+ messages in thread From: Romain Naour @ 2018-11-08 23:49 UTC (permalink / raw) To: buildroot Hi Thomas, I'm looking at this oldest patch in the patchwork... So, at the moment we use both hash (sysv and gnu) by default for toolchains with binutils >= 2.30, except for mips architecure which still use sysv hash. See [1]: # Enable gnu hash only on GNU targets, but not mips mips*-*-*) enable_default_hash_style=sysv ;; *-*-gnu* | *-*-linux* | *-*-nacl*) enable_default_hash_style=both ;; *) enable_default_hash_style=sysv ;; gnu hash style was introduced by [2] (binutils 2.18) The gnu hash style is enabled by default since binutils 2.30 [3] along with sysv hash style. If --hash-style option is supported by the compiler, glibc use both hash (sysv and gnu) [4]. But this doesn't mean that all binaries will be build with gnu style hash if binutils < 2.30. So, I'm not sure we want to enable only gnu style for all binaries on the target (especially the libc). Binaries that contains only gnu hash style are incompatible with binaries that contains only sysv hash style. The default for the choice should be BR2_GCC_HASH_STYLE_BOTH instead of BR2_GCC_HASH_STYLE_GNU if we want to make this option configurable. Best regards, Romain [1] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=blob;f=ld/configure;h=e46248cd089e71323ed20bc33ab0efdde526a2bc;hb=refs/heads/binutils-2_31-branch#l15884 [2] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=fdc90cb46b0f96dd4444ec3d126c87de75fb6e6b [3] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=2760f24c4942853eac7b921e4b8843d57a602654 [4] https://sourceware.org/git/?p=glibc.git;a=commit;h=871b91589bf4f6dfe19d5987b0a05bd7cf936ecc Le 17/12/2017 ? 15:30, Stefan Fr?berg a ?crit?: > Hi Thomas > > Well, I was just worried that if setting the linking hash style to stone > (aka "gnu") then could > it maybe break builds in some other archs than x86, x86_64 and ARM ? > > So I played carefull and made it configurable by choice. > > Im not sure but I think that option has been hiding in GCC since 4.x and > buildroot lowest is 4.9. > So if it's okay I can cook another patch where it just set's it in stone > without choice ? > > -S- > > Thomas Petazzoni kirjoitti 16.12.2017 klo 17:23: >> Hello, >> >> On Sat, 16 Dec 2017 01:25:30 +0200, Stefan Fr?berg wrote: >>> This will set the default hash style that GCC will >>> always use during linking. >>> >>> Signed-off-by: Stefan Fr?berg <stefan.froberg@petroprogram.com> >> Could you explain the motivation for configuring the default hash >> style? If "gnu" gives the best application startup time, why would we >> use a different one? >> >> Generally, the commit log lacks a bit of background, i.e the "why" we >> would want such a change. >> >> Thanks! >> >> Thomas > > _______________________________________________ > buildroot mailing list > buildroot at busybox.net > http://lists.busybox.net/mailman/listinfo/buildroot > ^ permalink raw reply [flat|nested] 10+ messages in thread
* [Buildroot] [PATCH 1/1] gcc: Support configure option --with-linker-hash-style 2018-11-08 23:49 ` Romain Naour @ 2018-11-09 21:35 ` Arnout Vandecappelle 2018-11-10 11:30 ` Romain Naour 0 siblings, 1 reply; 10+ messages in thread From: Arnout Vandecappelle @ 2018-11-09 21:35 UTC (permalink / raw) To: buildroot On 09/11/2018 00:49, Romain Naour wrote: > Hi Thomas, > > I'm looking at this oldest patch in the patchwork... Great! > > So, at the moment we use both hash (sysv and gnu) by default for toolchains with > binutils >= 2.30, except for mips architecure which still use sysv hash. > > See [1]: > # Enable gnu hash only on GNU targets, but not mips > mips*-*-*) enable_default_hash_style=sysv ;; > *-*-gnu* | *-*-linux* | *-*-nacl*) enable_default_hash_style=both ;; > *) enable_default_hash_style=sysv ;; > > gnu hash style was introduced by [2] (binutils 2.18) > > The gnu hash style is enabled by default since binutils 2.30 [3] along with sysv > hash style. To be exact: since 2.30, binutils has an option for the default hash style, and that default is "both" (except for mips), while before the default was "sysv". > If --hash-style option is supported by the compiler, ... which it is for all gcc versions we support... > glibc use both hash (sysv > and gnu) [4]. But this doesn't mean that all binaries will be build with gnu > style hash if binutils < 2.30. ... or if it is mips. However, if GCC is configured with --with-linker-hash-style=foo, then all binaries *will* actually be built with that hash style, no? > So, I'm not sure we want to enable only gnu style for all binaries on the target > (especially the libc). But if I understand correctly, glibc overrides it anyway and always sets "both"? So for glibc, at least, there shouldn't be a problem? As far as I understand, there shouldn't be a problem because all libraries and executables *will* be built with the same hash style. There may be three problems though: 1. If binutils defaults to "sysv" for mips, perhaps the GNU hash style is broken there? So perhaps we should disable the option for mips? 2. Some packages may (actually do) override the default hash style. So if you select hash style sysv in gcc, and use a libc which doesn't override it, and then try to link a program that itself overrides to hash style gnu, it will fail. 3. Similar for binary packages: we don't build them, so we don't control the hash style. Probably, though, binary packages will use hash style both. > Binaries that contains only gnu hash style are > incompatible with binaries that contains only sysv hash style. > > The default for the choice should be BR2_GCC_HASH_STYLE_BOTH instead of > BR2_GCC_HASH_STYLE_GNU if we want to make this option configurable. Or we could just bite the bullet and see how it goes wrong :-) It makes some kind of sense to make it configurable for now, so that there is a way out if there are a few packages that fail with the wrong hash style. But then at least we should randomize the options in the autobuilders. The good thing is that any problems will be immediately visible at link time (I think at least that that's the case; I hope it's not at dynamic load time that the problem occurs... And of course, dlopen()'ed libraries will only have runtime problems.) Regards, Arnout > > Best regards, > Romain > > [1] > https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=blob;f=ld/configure;h=e46248cd089e71323ed20bc33ab0efdde526a2bc;hb=refs/heads/binutils-2_31-branch#l15884 > [2] > https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=fdc90cb46b0f96dd4444ec3d126c87de75fb6e6b > [3] > https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=2760f24c4942853eac7b921e4b8843d57a602654 > [4] > https://sourceware.org/git/?p=glibc.git;a=commit;h=871b91589bf4f6dfe19d5987b0a05bd7cf936ecc > > Le 17/12/2017 ? 15:30, Stefan Fr?berg a ?crit?: >> Hi Thomas >> >> Well, I was just worried that if setting the linking hash style to stone >> (aka "gnu") then could >> it maybe break builds in some other archs than x86, x86_64 and ARM ? >> >> So I played carefull and made it configurable by choice. >> >> Im not sure but I think that option has been hiding in GCC since 4.x and >> buildroot lowest is 4.9. >> So if it's okay I can cook another patch where it just set's it in stone >> without choice ? >> >> -S- >> >> Thomas Petazzoni kirjoitti 16.12.2017 klo 17:23: >>> Hello, >>> >>> On Sat, 16 Dec 2017 01:25:30 +0200, Stefan Fr?berg wrote: >>>> This will set the default hash style that GCC will >>>> always use during linking. >>>> >>>> Signed-off-by: Stefan Fr?berg <stefan.froberg@petroprogram.com> >>> Could you explain the motivation for configuring the default hash >>> style? If "gnu" gives the best application startup time, why would we >>> use a different one? >>> >>> Generally, the commit log lacks a bit of background, i.e the "why" we >>> would want such a change. >>> >>> Thanks! >>> >>> Thomas >> >> _______________________________________________ >> buildroot mailing list >> buildroot at busybox.net >> http://lists.busybox.net/mailman/listinfo/buildroot >> > > _______________________________________________ > buildroot mailing list > buildroot at busybox.net > http://lists.busybox.net/mailman/listinfo/buildroot > ^ permalink raw reply [flat|nested] 10+ messages in thread
* [Buildroot] [PATCH 1/1] gcc: Support configure option --with-linker-hash-style 2018-11-09 21:35 ` Arnout Vandecappelle @ 2018-11-10 11:30 ` Romain Naour 0 siblings, 0 replies; 10+ messages in thread From: Romain Naour @ 2018-11-10 11:30 UTC (permalink / raw) To: buildroot Hi Arnout, Le 09/11/2018 ? 22:35, Arnout Vandecappelle a ?crit?: > > > On 09/11/2018 00:49, Romain Naour wrote: >> Hi Thomas, >> >> I'm looking at this oldest patch in the patchwork... > > Great! > >> >> So, at the moment we use both hash (sysv and gnu) by default for toolchains with >> binutils >= 2.30, except for mips architecure which still use sysv hash. >> >> See [1]: >> # Enable gnu hash only on GNU targets, but not mips >> mips*-*-*) enable_default_hash_style=sysv ;; >> *-*-gnu* | *-*-linux* | *-*-nacl*) enable_default_hash_style=both ;; >> *) enable_default_hash_style=sysv ;; >> >> gnu hash style was introduced by [2] (binutils 2.18) >> >> The gnu hash style is enabled by default since binutils 2.30 [3] along with sysv >> hash style. > > To be exact: since 2.30, binutils has an option for the default hash style, and > that default is "both" (except for mips), while before the default was "sysv". Indeed. > > >> If --hash-style option is supported by the compiler, > > ... which it is for all gcc versions we support... > >> glibc use both hash (sysv >> and gnu) [4]. But this doesn't mean that all binaries will be build with gnu >> style hash if binutils < 2.30. > > ... or if it is mips. > > However, if GCC is configured with --with-linker-hash-style=foo, then all > binaries *will* actually be built with that hash style, no? I'm not sure if gcc's "--with-linker-hash-style=foo" (added in 4.7.0 [1]) win against "-Wl,--hash-style=bar" added by glibc. (This also mean --with-linker-hash-style needs gcc >= 4.7.0). "Prepend --hash-style=LINKER_HASH_STYLE to whatever link_spec we had before." We should have : "--hash-style=foo --hash-style=bar" on the linker command line. ("bar" should be used in this case I believe) [1] https://github.com/gcc-mirror/gcc/commit/3cb9bbfa927aa187048534f9069202c017a78e38 > > >> So, I'm not sure we want to enable only gnu style for all binaries on the target >> (especially the libc). > > But if I understand correctly, glibc overrides it anyway and always sets > "both"? So for glibc, at least, there shouldn't be a problem? This must be verified. > > > As far as I understand, there shouldn't be a problem because all libraries and > executables *will* be built with the same hash style. There may be three > problems though: > > 1. If binutils defaults to "sysv" for mips, perhaps the GNU hash style is broken > there? So perhaps we should disable the option for mips? Well, we don't have any explanation in the commit log adding the --enable-default-hash-style option about mips. We don't know why we need to use sysv on mips. > > 2. Some packages may (actually do) override the default hash style. So if you > select hash style sysv in gcc, and use a libc which doesn't override it, and > then try to link a program that itself overrides to hash style gnu, it will fail. Indeed. IIUC it should be a runtime problem with the dynamic loader. I haven't tested this patch so far... > > 3. Similar for binary packages: we don't build them, so we don't control the > hash style. Probably, though, binary packages will use hash style both. Maybe we have to check each binary package (ex opengl Mali). > > >> Binaries that contains only gnu hash style are >> incompatible with binaries that contains only sysv hash style. >> >> The default for the choice should be BR2_GCC_HASH_STYLE_BOTH instead of >> BR2_GCC_HASH_STYLE_GNU if we want to make this option configurable. > > Or we could just bite the bullet and see how it goes wrong :-) :) > > It makes some kind of sense to make it configurable for now, so that there is a > way out if there are a few packages that fail with the wrong hash style. But > then at least we should randomize the options in the autobuilders. The good > thing is that any problems will be immediately visible at link time (I think at > least that that's the case; I hope it's not at dynamic load time that the > problem occurs... And of course, dlopen()'ed libraries will only have runtime > problems.) Actually, it's not clear to me about the need of using hash sysv only or gnu only, why using both hash is not sufficient? Best regards, Romain > > > Regards, > Arnout > > >> >> Best regards, >> Romain >> >> [1] >> https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=blob;f=ld/configure;h=e46248cd089e71323ed20bc33ab0efdde526a2bc;hb=refs/heads/binutils-2_31-branch#l15884 >> [2] >> https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=fdc90cb46b0f96dd4444ec3d126c87de75fb6e6b >> [3] >> https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=2760f24c4942853eac7b921e4b8843d57a602654 >> [4] >> https://sourceware.org/git/?p=glibc.git;a=commit;h=871b91589bf4f6dfe19d5987b0a05bd7cf936ecc >> >> Le 17/12/2017 ? 15:30, Stefan Fr?berg a ?crit?: >>> Hi Thomas >>> >>> Well, I was just worried that if setting the linking hash style to stone >>> (aka "gnu") then could >>> it maybe break builds in some other archs than x86, x86_64 and ARM ? >>> >>> So I played carefull and made it configurable by choice. >>> >>> Im not sure but I think that option has been hiding in GCC since 4.x and >>> buildroot lowest is 4.9. >>> So if it's okay I can cook another patch where it just set's it in stone >>> without choice ? >>> >>> -S- >>> >>> Thomas Petazzoni kirjoitti 16.12.2017 klo 17:23: >>>> Hello, >>>> >>>> On Sat, 16 Dec 2017 01:25:30 +0200, Stefan Fr?berg wrote: >>>>> This will set the default hash style that GCC will >>>>> always use during linking. >>>>> >>>>> Signed-off-by: Stefan Fr?berg <stefan.froberg@petroprogram.com> >>>> Could you explain the motivation for configuring the default hash >>>> style? If "gnu" gives the best application startup time, why would we >>>> use a different one? >>>> >>>> Generally, the commit log lacks a bit of background, i.e the "why" we >>>> would want such a change. >>>> >>>> Thanks! >>>> >>>> Thomas >>> >>> _______________________________________________ >>> buildroot mailing list >>> buildroot at busybox.net >>> http://lists.busybox.net/mailman/listinfo/buildroot >>> >> >> _______________________________________________ >> buildroot mailing list >> buildroot at busybox.net >> http://lists.busybox.net/mailman/listinfo/buildroot >> > _______________________________________________ > buildroot mailing list > buildroot at busybox.net > http://lists.busybox.net/mailman/listinfo/buildroot > ^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2018-11-10 11:30 UTC | newest] Thread overview: 10+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2017-12-15 23:25 [Buildroot] [PATCH 1/1] gcc: Support configure option --with-linker-hash-style Stefan Fröberg 2017-12-15 23:27 ` [Buildroot] FW: " Kees van Unen 2017-12-16 1:50 ` Carlos Santos 2017-12-16 1:51 ` [Buildroot] FW: " Kees van Unen 2017-12-16 12:11 ` [Buildroot] " Thomas Petazzoni 2017-12-16 15:23 ` [Buildroot] " Thomas Petazzoni 2017-12-17 14:30 ` Stefan Fröberg 2018-11-08 23:49 ` Romain Naour 2018-11-09 21:35 ` Arnout Vandecappelle 2018-11-10 11:30 ` Romain Naour
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox