* [PATCH] riscv: fix vdso build with lld
@ 2020-04-02 8:55 Ilie Halip
2020-04-02 17:35 ` Nick Desaulniers
0 siblings, 1 reply; 3+ messages in thread
From: Ilie Halip @ 2020-04-02 8:55 UTC (permalink / raw)
To: linux-riscv
Cc: Ilie Halip, Paul Walmsley, Palmer Dabbelt, Albert Ou,
Greg Kroah-Hartman, Mao Han, Nick Desaulniers, Thomas Gleixner,
linux-kernel, clang-built-linux
When building with the LLVM linker this error occurrs:
LD arch/riscv/kernel/vdso/vdso-syms.o
ld.lld: error: no input files
This happens because the lld treats -R as an alias to -rpath, as opposed
to ld where -R means --just-symbols.
Use the long option name for compatibility between the two.
Link: https://github.com/ClangBuiltLinux/linux/issues/805
Reported-by: Dmitry Golovin <dima@golovin.in>
Signed-off-by: Ilie Halip <ilie.halip@gmail.com>
---
arch/riscv/kernel/vdso/Makefile | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index 33b16f4212f7..19f7b9ea10ab 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -41,7 +41,8 @@ SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
$(obj)/vdso-dummy.o: $(src)/vdso.lds $(obj)/rt_sigreturn.o FORCE
$(call if_changed,vdsold)
-LDFLAGS_vdso-syms.o := -r -R
+# lld aliases -R to -rpath; use the longer option name
+LDFLAGS_vdso-syms.o := -r --just-symbols
$(obj)/vdso-syms.o: $(obj)/vdso-dummy.o FORCE
$(call if_changed,ld)
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] riscv: fix vdso build with lld 2020-04-02 8:55 [PATCH] riscv: fix vdso build with lld Ilie Halip @ 2020-04-02 17:35 ` Nick Desaulniers 2020-04-02 17:53 ` Fangrui Song 0 siblings, 1 reply; 3+ messages in thread From: Nick Desaulniers @ 2020-04-02 17:35 UTC (permalink / raw) To: Ilie Halip Cc: linux-riscv, Paul Walmsley, Palmer Dabbelt, Albert Ou, Greg Kroah-Hartman, Mao Han, Thomas Gleixner, LKML, clang-built-linux, Jordan Rupprecht, Fangrui Song + Jordan, Fangrui On Thu, Apr 2, 2020 at 1:56 AM Ilie Halip <ilie.halip@gmail.com> wrote: > > When building with the LLVM linker this error occurrs: > LD arch/riscv/kernel/vdso/vdso-syms.o > ld.lld: error: no input files > > This happens because the lld treats -R as an alias to -rpath, as opposed > to ld where -R means --just-symbols. > > Use the long option name for compatibility between the two. > > Link: https://github.com/ClangBuiltLinux/linux/issues/805 > Reported-by: Dmitry Golovin <dima@golovin.in> > Signed-off-by: Ilie Halip <ilie.halip@gmail.com> > --- > arch/riscv/kernel/vdso/Makefile | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile > index 33b16f4212f7..19f7b9ea10ab 100644 > --- a/arch/riscv/kernel/vdso/Makefile > +++ b/arch/riscv/kernel/vdso/Makefile > @@ -41,7 +41,8 @@ SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \ > $(obj)/vdso-dummy.o: $(src)/vdso.lds $(obj)/rt_sigreturn.o FORCE > $(call if_changed,vdsold) > > -LDFLAGS_vdso-syms.o := -r -R > +# lld aliases -R to -rpath; use the longer option name Thanks for the patch. Maybe the comment can be dropped? It doesn't make sense if there's no -R in the source file you're touching. If someone cares about why `--just-symbols` is spelled out, that's what `git log` or vim fugitive is for. Maybe the maintainer would be kind enough to just drop that line for you when merging? Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Jordan, Fangrui, thoughts on this? Sounds like something other users of LLD might run into porting their codebase to LLVM's linker. $ ld.lld --help | grep \\-R -R <value> Alias for --rpath $ ld.bfd --help | grep \\-R -R FILE, --just-symbols FILE > +LDFLAGS_vdso-syms.o := -r --just-symbols > $(obj)/vdso-syms.o: $(obj)/vdso-dummy.o FORCE > $(call if_changed,ld) > > -- > 2.17.1 > -- Thanks, ~Nick Desaulniers ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] riscv: fix vdso build with lld 2020-04-02 17:35 ` Nick Desaulniers @ 2020-04-02 17:53 ` Fangrui Song 0 siblings, 0 replies; 3+ messages in thread From: Fangrui Song @ 2020-04-02 17:53 UTC (permalink / raw) To: Nick Desaulniers, Ilie Halip Cc: linux-riscv, Paul Walmsley, Palmer Dabbelt, Albert Ou, Greg Kroah-Hartman, Mao Han, Thomas Gleixner, LKML, clang-built-linux, Jordan Rupprecht The comment of `With ld -R we can then ...` should be fixed as well. On 2020-04-02, Nick Desaulniers wrote: >+ Jordan, Fangrui > >On Thu, Apr 2, 2020 at 1:56 AM Ilie Halip <ilie.halip@gmail.com> wrote: >> >> When building with the LLVM linker this error occurrs: >> LD arch/riscv/kernel/vdso/vdso-syms.o >> ld.lld: error: no input files >> >> This happens because the lld treats -R as an alias to -rpath, as opposed >> to ld where -R means --just-symbols. >> >> Use the long option name for compatibility between the two. >> >> Link: https://github.com/ClangBuiltLinux/linux/issues/805 >> Reported-by: Dmitry Golovin <dima@golovin.in> >> Signed-off-by: Ilie Halip <ilie.halip@gmail.com> >> --- >> arch/riscv/kernel/vdso/Makefile | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile >> index 33b16f4212f7..19f7b9ea10ab 100644 >> --- a/arch/riscv/kernel/vdso/Makefile >> +++ b/arch/riscv/kernel/vdso/Makefile >> @@ -41,7 +41,8 @@ SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \ >> $(obj)/vdso-dummy.o: $(src)/vdso.lds $(obj)/rt_sigreturn.o FORCE >> $(call if_changed,vdsold) >> >> -LDFLAGS_vdso-syms.o := -r -R >> +# lld aliases -R to -rpath; use the longer option name > >Thanks for the patch. Maybe the comment can be dropped? It doesn't >make sense if there's no -R in the source file you're touching. If >someone cares about why `--just-symbols` is spelled out, that's what >`git log` or vim fugitive is for. Maybe the maintainer would be kind >enough to just drop that line for you when merging? > >Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > >Jordan, Fangrui, thoughts on this? Sounds like something other users >of LLD might run into porting their codebase to LLVM's linker. Independently, I noticed this ~2 days ago. https://reviews.llvm.org/D76885#1952860 GNU ld parses options with getopt_long and -j is recognized as --just-symbols ('R') because there is no other long options prefixed with -j. Now, the following comment applies. Basically, --just-symbols/-R is an overloaded option. It can be used as an -rpath if the argument is a directory. The best practice is to use either -rpath or --just-symbols, never -R. // binutils-gdb/ld/lexsup.c case 'R': /* The GNU linker traditionally uses -R to mean to include only the symbols from a file. The Solaris linker uses -R to set the path used by the runtime linker to find libraries. This is the GNU linker -rpath argument. We try to support both simultaneously by checking the file named. If it is a directory, rather than a regular file, we assume -rpath was meant. */ { struct stat s; if (stat (optarg, &s) >= 0 && ! S_ISDIR (s.st_mode)) { lang_add_input_file (optarg, lang_input_file_is_symbols_only_enum, NULL); break; } } >$ ld.lld --help | grep \\-R > -R <value> Alias for --rpath >$ ld.bfd --help | grep \\-R > -R FILE, --just-symbols FILE > >> +LDFLAGS_vdso-syms.o := -r --just-symbols >> $(obj)/vdso-syms.o: $(obj)/vdso-dummy.o FORCE >> $(call if_changed,ld) >> >> -- >> 2.17.1 >> > > >-- >Thanks, >~Nick Desaulniers ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-04-02 17:54 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-04-02 8:55 [PATCH] riscv: fix vdso build with lld Ilie Halip 2020-04-02 17:35 ` Nick Desaulniers 2020-04-02 17:53 ` Fangrui Song
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