[lld] r262910 - ELF: Add /lib and /usr/lib as default search paths.
Rui Ueyama via llvm-commits
llvm-commits at lists.llvm.org
Tue Mar 8 13:10:50 PST 2016
OK, so the default search path is more complicated than I thought.
It seems that gold has built-in search paths that can be configured at
./configure time. I don't think we want to do that because we generally
don't solve an issue by adding more knobs and handles which inevitably
increase complexity.
It is probably the same situation as --dynamic-linker? We expect that the
compiler always passes the correct dynamic linker path through the option
or we do not create .interp section.
On Tue, Mar 8, 2016 at 9:20 AM, Rafael Espíndola <rafael.espindola at gmail.com
> wrote:
> Sorry, I reverted this.
>
> The problem is that it broke linking on Fedora 64 bits. There the
> default search path should be /lib64 /usr/lib64.
>
> It is probably better to try to stay out of the business of knowing
> the defaults of multiple systems. The vast majority or links are
> started by the driver and it passes all the necessary -L options.
>
> Cheers,
> Rafael
>
>
> On 7 March 2016 at 23:06, Rui Ueyama via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
> > Author: ruiu
> > Date: Mon Mar 7 22:06:27 2016
> > New Revision: 262910
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=262910&view=rev
> > Log:
> > ELF: Add /lib and /usr/lib as default search paths.
> >
> > GNU ld and gold have these paths as default search paths.
> > If you don't want these directories, pass -nostdlib.
> >
> > Added:
> > lld/trunk/test/ELF/Inputs/nostdlib.s
> > lld/trunk/test/ELF/nostdlib.s
> > Modified:
> > lld/trunk/ELF/Config.h
> > lld/trunk/ELF/Driver.cpp
> > lld/trunk/ELF/LinkerScript.cpp
> > lld/trunk/ELF/Options.td
> >
> > Modified: lld/trunk/ELF/Config.h
> > URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Config.h?rev=262910&r1=262909&r2=262910&view=diff
> >
> ==============================================================================
> > --- lld/trunk/ELF/Config.h (original)
> > +++ lld/trunk/ELF/Config.h Mon Mar 7 22:06:27 2016
> > @@ -67,6 +67,7 @@ struct Configuration {
> > bool Mips64EL = false;
> > bool NoInhibitExec;
> > bool NoUndefined;
> > + bool Nostdlib;
> > bool PrintGcSections;
> > bool Relocatable;
> > bool Shared;
> >
> > Modified: lld/trunk/ELF/Driver.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Driver.cpp?rev=262910&r1=262909&r2=262910&view=diff
> >
> ==============================================================================
> > --- lld/trunk/ELF/Driver.cpp (original)
> > +++ lld/trunk/ELF/Driver.cpp Mon Mar 7 22:06:27 2016
> > @@ -207,9 +207,6 @@ void LinkerDriver::main(ArrayRef<const c
> >
> > // Initializes Config members by the command line options.
> > void LinkerDriver::readConfigs(opt::InputArgList &Args) {
> > - for (auto *Arg : Args.filtered(OPT_L))
> > - Config->SearchPaths.push_back(Arg->getValue());
> > -
> > std::vector<StringRef> RPaths;
> > for (auto *Arg : Args.filtered(OPT_rpath))
> > RPaths.push_back(Arg->getValue());
> > @@ -237,6 +234,7 @@ void LinkerDriver::readConfigs(opt::Inpu
> > Config->ICF = Args.hasArg(OPT_icf);
> > Config->NoInhibitExec = Args.hasArg(OPT_noinhibit_exec);
> > Config->NoUndefined = Args.hasArg(OPT_no_undefined);
> > + Config->Nostdlib = Args.hasArg(OPT_nostdlib);
> > Config->PrintGcSections = Args.hasArg(OPT_print_gc_sections);
> > Config->Relocatable = Args.hasArg(OPT_relocatable);
> > Config->Shared = Args.hasArg(OPT_shared);
> > @@ -279,6 +277,14 @@ void LinkerDriver::readConfigs(opt::Inpu
> >
> > for (auto *Arg : Args.filtered(OPT_undefined))
> > Config->Undefined.push_back(Arg->getValue());
> > +
> > + if (!Config->Nostdlib) {
> > + Config->SearchPaths.push_back("=/lib");
> > + Config->SearchPaths.push_back("=/usr/lib");
> > + }
> > +
> > + for (auto *Arg : Args.filtered(OPT_L))
> > + Config->SearchPaths.push_back(Arg->getValue());
> > }
> >
> > void LinkerDriver::createFiles(opt::InputArgList &Args) {
> >
> > Modified: lld/trunk/ELF/LinkerScript.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LinkerScript.cpp?rev=262910&r1=262909&r2=262910&view=diff
> >
> ==============================================================================
> > --- lld/trunk/ELF/LinkerScript.cpp (original)
> > +++ lld/trunk/ELF/LinkerScript.cpp Mon Mar 7 22:06:27 2016
> > @@ -396,7 +396,9 @@ void ScriptParser::readOutputFormat() {
> >
> > void ScriptParser::readSearchDir() {
> > expect("(");
> > - Config->SearchPaths.push_back(next());
> > + StringRef Path = next();
> > + if (!Config->Nostdlib)
> > + Config->SearchPaths.push_back(Path);
> > expect(")");
> > }
> >
> >
> > Modified: lld/trunk/ELF/Options.td
> > URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Options.td?rev=262910&r1=262909&r2=262910&view=diff
> >
> ==============================================================================
> > --- lld/trunk/ELF/Options.td (original)
> > +++ lld/trunk/ELF/Options.td Mon Mar 7 22:06:27 2016
> > @@ -91,6 +91,9 @@ def noinhibit_exec : Flag<["--"], "noinh
> > def no_undefined : Flag<["--"], "no-undefined">,
> > HelpText<"Report unresolved symbols even if the linker is creating a
> shared library">;
> >
> > +def nostdlib: Flag<["-", "--"], "nostdlib">,
> > + HelpText<"Only search directories specified on the command line">;
> > +
> > def o : JoinedOrSeparate<["-"], "o">, MetaVarName<"<path>">,
> > HelpText<"Path to file to write output">;
> >
> >
> > Added: lld/trunk/test/ELF/Inputs/nostdlib.s
> > URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/Inputs/nostdlib.s?rev=262910&view=auto
> >
> ==============================================================================
> > --- lld/trunk/test/ELF/Inputs/nostdlib.s (added)
> > +++ lld/trunk/test/ELF/Inputs/nostdlib.s Mon Mar 7 22:06:27 2016
> > @@ -0,0 +1,3 @@
> > +.globl foo
> > +foo:
> > + ret
> >
> > Added: lld/trunk/test/ELF/nostdlib.s
> > URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/nostdlib.s?rev=262910&view=auto
> >
> ==============================================================================
> > --- lld/trunk/test/ELF/nostdlib.s (added)
> > +++ lld/trunk/test/ELF/nostdlib.s Mon Mar 7 22:06:27 2016
> > @@ -0,0 +1,16 @@
> > +# REQUIRES: x86
> > +
> > +# RUN: mkdir -p %t.dir/lib
> > +# RUN: mkdir -p %t.dir/usr/lib
> > +# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t1.o
> > +# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux
> %p/Inputs/nostdlib.s -o %t2.o
> > +# RUN: ld.lld -shared -o %t.dir/lib/libfoo.so %t2.o
> > +# RUN: ld.lld -shared -o %t.dir/usr/lib/libbar.so %t2.o
> > +# RUN: ld.lld --sysroot=%t.dir -o %t %t1.o -lfoo
> > +# RUN: ld.lld --sysroot=%t.dir -o %t %t1.o -lbar
> > +# RUN: not ld.lld --sysroot=%t.dir -nostdlib -o %t %t1.o -lfoo
> > +# RUN: not ld.lld --sysroot=%t.dir -nostdlib -o %t %t1.o -lbar
> > +
> > +.globl _start
> > +_start:
> > + ret
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org
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>
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