Ping
> Le 20 oct. 2018 à 12:18, Romain Geissler <romain.geiss...@amadeus.com> a
> écrit :
>
> Hi,
>
> I would like to raise again the question of supporting -fuse-ld=ldd. A
> patch implementing it was already submitted in
> https://gcc.gnu.org/ml/gcc-patches/2016-06/msg01722.html by Davide
> Italiano. This patch still applies correctly to current trunk. I am CC-ing
> the original author and re-posting it here unchanged for reference.
>
> I think we can consider this patch as relevant despite the goals and
> licence difference of LLVM vs GNU, based on what was written by Mike Stump
> in https://gcc.gnu.org/ml/gcc-patches/2016-07/msg00157.html
>
> Back then, the technical problem raised by lld was reported as
> https://bugs.llvm.org/show_bug.cgi?id=28414 now closed. In this bug, every
> reported problems have been fixed except the last one. H.J. Lu mentions
> this last problem (lld does not produces symbol versions predecessor
> relationship while ld.bfd and ld.gold do, which seems to be a decision
> taken on purpose and advertised as a harmless change) as being one reason
> against supporting in -fuse-ld=ldd in gcc. Is it still the case today, and
> if yes, why ?
>
> Is there any other reason why -fuse-ld=ldd shall not be supported by gcc ?
>
> Cheers,
> Romain
>
> 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;
