On Mon, Jul 4, 2016 at 9:12 AM, H.J. Lu <hjl.to...@gmail.com> wrote:
> On Sun, Jul 3, 2016 at 9:38 PM, Davide Italiano <dccitali...@gmail.com> wrote:
>> On Thu, Jun 23, 2016 at 9:11 PM, Davide Italiano <dccitali...@gmail.com>
>> wrote:
>>> + HJ who wrote the code for the option originally.
>>>
>>> On Thu, Jun 23, 2016 at 9:01 PM, Davide Italiano <dccitali...@gmail.com>
>>> wrote:
>>>> LLVM currently ships with a new ELF linker http://lld.llvm.org/.
>>>> I experiment a lot with gcc and lld so it would be nice if
>>>> -fuse-ld=lld is supported (considering the linker is now mature enough
>>>> to link large C/C++ applications).
>>>>
>>>> Also, IMHO, -fuse-ld should be a generic facility which accept other
>>>> linkers (as long as they follow the convention ld.<arg>), and should
>>>> also support absolute path, e.g. -fuse-ld=/usr/local/bin/ld.mylinker.
>>>> Probably outside of the scope of this patch, but I thought worth
>>>> mentioning.
>>>>
>>>> Thanks,
>>>>
>>
>> Hi, can anybody take a look?
>>
>> Thanks,
>
> lld won't build on Fedora 24/x86-64 with GCC 6:
>
> [ 39%] Building CXX object
> tools/lld/ELF/CMakeFiles/lldELF.dir/OutputSections.cpp.o
> /export/gnu/import/git/llvm/tools/lld/ELF/OutputSections.cpp: In
> member function ‘void
> lld::elf::GnuHashTableSection<ELFT>::addSymbols(std::vector<std::pair<lld::elf::SymbolBody*,
> long unsigned int> >&)’:
> /export/gnu/import/git/llvm/tools/lld/ELF/OutputSections.cpp:585:8:
> error: inconsistent deduction for ‘auto’: ‘auto’ and then
> ‘__gnu_cxx::__normal_iterator<std::pair<lld::elf::SymbolBody*, long
> unsigned int>*, std::vector<std::pair<lld::elf::SymbolBody*, long
> unsigned int> > >’
> tools/lld/ELF/CMakeFiles/lldELF.dir/build.make:302: recipe for target
> 'tools/lld/ELF/CMakeFiles/lldELF.dir/OutputSections.cpp.o' failed
> gmake[4]: *** [tools/lld/ELF/CMakeFiles/lldELF.dir/OutputSections.cpp.o]
> Error 1
>
> Can you fix it?
>> --
>> Davide
>>
>>>> --
>>>> Davide
>>>>
>>>> From 323c23d79c91d7dcee2f29b9ced8c1c00703d346 Mon Sep 17 00:00:00 2001
>>>> From: Davide Italiano <dccitali...@gmail.com>
>>>> Date: Thu, 23 Jun 2016 20:51:53 -0700
>>>> Subject: [PATCH] Driver: Add support for -fuse-ld=lld.
>>>>
>>>> * collect2.c (main): Support -fuse-ld=lld.
>>>>
>>>> * common.opt: Add fuse-ld=lld
>>>>
>>>> * doc/invoke.texi: Document -fuse-ld=lld
>>>>
>>>> * opts.c: Ignore -fuse-ld=lld
>>>> ---
>>>> gcc/collect2.c | 11 ++++++++---
>>>> gcc/common.opt | 4 ++++
>>>> gcc/doc/invoke.texi | 4 ++++
>>>> gcc/opts.c | 1 +
>>>> 4 files changed, 17 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/gcc/collect2.c b/gcc/collect2.c
>>>> index bffac80..6a8387c 100644
>>>> --- a/gcc/collect2.c
>>>> +++ b/gcc/collect2.c
>>>> @@ -831,6 +831,7 @@ main (int argc, char **argv)
>>>> USE_PLUGIN_LD,
>>>> USE_GOLD_LD,
>>>> USE_BFD_LD,
>>>> + USE_LLD_LD,
>>>> USE_LD_MAX
>>>> } selected_linker = USE_DEFAULT_LD;
>>>> static const char *const ld_suffixes[USE_LD_MAX] =
>>>> @@ -838,7 +839,8 @@ main (int argc, char **argv)
>>>> "ld",
>>>> PLUGIN_LD_SUFFIX,
>>>> "ld.gold",
>>>> - "ld.bfd"
>>>> + "ld.bfd",
>>>> + "ld.lld"
>>>> };
>>>> static const char *const real_ld_suffix = "real-ld";
>>>> static const char *const collect_ld_suffix = "collect-ld";
>>>> @@ -1004,6 +1006,8 @@ main (int argc, char **argv)
>>>> selected_linker = USE_BFD_LD;
>>>> else if (strcmp (argv[i], "-fuse-ld=gold") == 0)
>>>> selected_linker = USE_GOLD_LD;
>>>> + else if (strcmp (argv[i], "-fuse-ld=lld") == 0)
>>>> + selected_linker = USE_LLD_LD;
>>>>
>>>> #ifdef COLLECT_EXPORT_LIST
>>>> /* These flags are position independent, although their order
>>>> @@ -1093,7 +1097,8 @@ main (int argc, char **argv)
>>>> /* Maybe we know the right file to use (if not cross). */
>>>> ld_file_name = 0;
>>>> #ifdef DEFAULT_LINKER
>>>> - if (selected_linker == USE_BFD_LD || selected_linker == USE_GOLD_LD)
>>>> + if (selected_linker == USE_BFD_LD || selected_linker == USE_GOLD_LD ||
>>>> + selected_linker == USE_LLD_LD)
>>>> {
>>>> char *linker_name;
>>>> # ifdef HOST_EXECUTABLE_SUFFIX
>>>> @@ -1307,7 +1312,7 @@ main (int argc, char **argv)
>>>> else if (!use_collect_ld
>>>> && strncmp (arg, "-fuse-ld=", 9) == 0)
>>>> {
>>>> - /* Do not pass -fuse-ld={bfd|gold} to the linker. */
>>>> + /* Do not pass -fuse-ld={bfd|gold|lld} to the linker. */
>>>> ld1--;
>>>> ld2--;
>>>> }
>>>> diff --git a/gcc/common.opt b/gcc/common.opt
>>>> index 5d90385..2a95a1f 100644
>>>> --- a/gcc/common.opt
>>>> +++ b/gcc/common.opt
>>>> @@ -2536,6 +2536,10 @@ fuse-ld=gold
>>>> Common Driver Negative(fuse-ld=bfd)
>>>> Use the gold linker instead of the default linker.
>>>>
>>>> +fuse-ld=lld
>>>> +Common Driver Negative(fuse-ld=lld)
>>>> +Use the lld LLVM linker instead of the default linker.
>>>> +
>>>> fuse-linker-plugin
>>>> Common Undocumented Var(flag_use_linker_plugin)
>>>>
>>>> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
>>>> index 2c87c53..4b8acff 100644
>>>> --- a/gcc/doc/invoke.texi
>>>> +++ b/gcc/doc/invoke.texi
>>>> @@ -10651,6 +10651,10 @@ Use the @command{bfd} linker instead of the
>>>> default linker.
>>>> @opindex fuse-ld=gold
>>>> Use the @command{gold} linker instead of the default linker.
>>>>
>>>> +@item -fuse-ld=lld
>>>> +@opindex fuse-ld=lld
>>>> +Use the LLVM @command{lld} linker instead of the default linker.
>>>> +
>>>> @cindex Libraries
>>>> @item -l@var{library}
>>>> @itemx -l @var{library}
>>>> diff --git a/gcc/opts.c b/gcc/opts.c
>>>> index 7406210..f2c86f7 100644
>>>> --- a/gcc/opts.c
>>>> +++ b/gcc/opts.c
>>>> @@ -2178,6 +2178,7 @@ common_handle_option (struct gcc_options *opts,
>>>>
>>>> case OPT_fuse_ld_bfd:
>>>> case OPT_fuse_ld_gold:
>>>> + case OPT_fuse_ld_lld:
>>>> case OPT_fuse_linker_plugin:
>>>> /* No-op. Used by the driver and passed to us because it starts
>>>> with f.*/
>>>> break;
>>>> --
>>>> 2.5.5
>
>
>
> --
> H.J.
FWIW, this should be fixed upstream.
