On 7/3/20 7:18 PM, Fāng-ruì Sòng wrote:
On 2020-07-03, Martin Liška wrote:
On 7/2/20 9:34 PM, Fāng-ruì Sòng wrote:
On 2020-07-01, Fāng-ruì Sòng wrote:
On 2020-07-01, Martin Liška wrote:
On 6/30/20 5:32 PM, Fāng-ruì Sòng wrote:
There is some concern about clang's -fuse-ld=path
http://lists.llvm.org/pipermail/cfe-dev/2020-June/065710.html and use
of COMPILER_PATH vs PATH.
Shall we introduce another option like -fld-path=path (PATH is used,
COMPILER_PATH is not used)?
I would recommend first landing a patch to LLVM and then we can do
a corresponding change to GCC.
Martin
Thank a lot for you welcoming words! This is what I intend to add for clang:
https://reviews.llvm.org/D83015
I'll create a GCC patch superseding this one later.
Attached the new patch.
Thank you for the update patch:
From e7f86cdcaf03e4ddb98d0df9d07894d9ffb7d91a Mon Sep 17 00:00:00 2001
From: Fangrui Song <mask...@google.com>
Date: Thu, 2 Jul 2020 12:26:09 -0700
Subject: [PATCH] Add -fld-path= to specify an arbitrary executable as the
linker
The value can be either a relative path (relative to a COMPILER_PATH
directory or a PATH directory) or an absolute path. -fld-path=
complements -fuse-ld={bfd,gold,lld} which specifies the linker flavor.
PR driver/93645
* common.opt (-fld-path=): Add -fld-path=
* opts.c (common_handle_option): Handle OPT_fld_path_.
* gcc.c (driver_handle_option): Likewise.
* collect2.c (main): Likewise.
* doc/invoke.texi: Document -fld-path=.
---
gcc/collect2.c | 57 ++++++++++++++++++++++++++++++++-------------
gcc/common.opt | 4 ++++
gcc/doc/invoke.texi | 6 +++++
gcc/gcc.c | 2 +-
gcc/opts.c | 1 +
5 files changed, 53 insertions(+), 17 deletions(-)
diff --git a/gcc/collect2.c b/gcc/collect2.c
index f8a5ce45994..efa652f7f82 100644
--- a/gcc/collect2.c
+++ b/gcc/collect2.c
@@ -844,6 +844,7 @@ main (int argc, char **argv)
const char **ld1;
bool use_plugin = false;
bool use_collect_ld = false;
+ const char *ld_path = NULL;
/* The kinds of symbols we will have to consider when scanning the
outcome of a first pass link. This is ALL to start with, then might
@@ -961,12 +962,21 @@ main (int argc, char **argv)
if (selected_linker == USE_DEFAULT_LD)
selected_linker = USE_PLUGIN_LD;
}
- else if (strcmp (argv[i], "-fuse-ld=bfd") == 0)
- 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;
+ else if (strncmp (argv[i], "-fuse-ld=bfd", 9) == 0
+ && selected_linker != USE_LD_MAX)
+ {
This does not seem correct to me. You match -fuse-ld=bfd and then
test other option values in the following block.
This is correct but I probably should use:
- strncmp (argv[i], "-fuse-ld=bfd", 9) == 0
+ strncmp (argv[i], "-fuse-ld=", 9) == 0
Yes, that would be much better.
+ if (strcmp (argv[i] + 9, "bfd") == 0)
+ selected_linker = USE_BFD_LD;
+ else if (strcmp (argv[i] + 9, "gold") == 0)
+ selected_linker = USE_GOLD_LD;
+ else if (strcmp (argv[i] + 9, "lld") == 0)
+ selected_linker = USE_LLD_LD;
+ }
+ else if (strncmp (argv[i], "-fld-path=", 10) == 0)
+ {
+ ld_path = argv[i] + 10;
+ selected_linker = USE_LD_MAX;
+ }
else if (strncmp (argv[i], "-o", 2) == 0)
{
/* Parse the output filename if it's given so that we can make
@@ -1117,14 +1127,27 @@ main (int argc, char **argv)
ld_file_name = find_a_file (&cpath, collect_ld_suffix, X_OK);
use_collect_ld = ld_file_name != 0;
}
- /* Search the compiler directories for `ld'. We have protection against
- recursive calls in find_a_file. */
- if (ld_file_name == 0)
- ld_file_name = find_a_file (&cpath, ld_suffixes[selected_linker], X_OK);
- /* Search the ordinary system bin directories
- for `ld' (if native linking) or `TARGET-ld' (if cross). */
- if (ld_file_name == 0)
- ld_file_name = find_a_file (&path, full_ld_suffixes[selected_linker],
X_OK);
+ if (selected_linker == USE_LD_MAX)
+ {
+ /* If -fld-path= does not contain a slash, search for the command using
+ the PATH environment variable. */
We also support file systems like Windows where the comment about a slash will
be misleading.
You can just mention relative vs. absolute path.
The behavior is modeled after
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html
Command Search and Execution
e. Otherwise, the command shall be searched for using the PATH environment
variable as described in XBD Environment Variables :
is performed if "the command name does not contain any <slash> characters".
For your suggestion, I think 'word' can mean a relative path as well, along
with 'rel\path' and 'rel/path'.
Should I say
If -fld-path= does not contain a path component separator (e.g. slash),
search for the command using
?
Seems file to me.
+ if (lbasename (ld_path) == ld_path)
Does it really return the same pointer? Maybe strcmp can be needed?
lbasename returns a const char * referencing a place of the string.
lto-wrapper.s has a similar use case:
Fine then.
1542: if (!dumppfx || lbasename (dumppfx) == dumppfx)
+ ld_file_name = find_a_file (&path, ld_path, X_OK);
+ else if (file_exists (ld_path))
+ ld_file_name = ld_path;
+ }
+ else
+ {
+ /* Search the compiler directories for `ld'. We have protection against
+ recursive calls in find_a_file. */
+ if (ld_file_name == 0)
+ ld_file_name = find_a_file (&cpath, ld_suffixes[selected_linker], X_OK);
+ /* Search the ordinary system bin directories
+ for `ld' (if native linking) or `TARGET-ld' (if cross). */
+ if (ld_file_name == 0)
+ ld_file_name =
+ find_a_file (&path, full_ld_suffixes[selected_linker], X_OK);
+ }
#ifdef REAL_NM_FILE_NAME
nm_file_name = find_a_file (&path, REAL_NM_FILE_NAME, X_OK);
@@ -1297,9 +1320,11 @@ main (int argc, char **argv)
#endif
}
else if (!use_collect_ld
- && strncmp (arg, "-fuse-ld=", 9) == 0)
+ && (strncmp (arg, "-fuse-ld=", 9) == 0 ||
+ strncmp (arg, "-fld-path=", 10) == 0))
{
- /* Do not pass -fuse-ld={bfd|gold|lld} to the linker. */
+ /* Do not pass -fuse-ld={bfd|gold|lld} or -fld-path= to the
+ linker. */
ld1--;
ld2--;
}
diff --git a/gcc/common.opt b/gcc/common.opt
index df8af365d1b..d5dfbb5c9c6 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2919,6 +2919,10 @@ fuse-ld=lld
Common Driver Negative(fuse-ld=lld)
Use the lld LLVM linker instead of the default linker.
+fld-path=
+Common Driver Joined
+Use the specified executable 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 e21d8a5217b..bfb6222f96b 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -14651,6 +14651,12 @@ Use the @command{gold} linker instead of the default
linker.
@opindex fuse-ld=lld
Use the LLVM @command{lld} linker instead of the default linker.
+@item -fld-path=@var{linker}
+@opindex fld-path=linker
+Use the specified executable named @var{linker} instead of the default linker.
+If @var{linker} does not contain any slash character, the linker will be
+searched for using @env{PATH}. This option overrides @option{-fuse-ld=}.
The slash comment applies here as well.
Martin
Ack. Will update when I get a clarification regarding the previous comment.
Thanks,
Martin
+
@cindex Libraries
@item -l@var{library}
@itemx -l @var{library}
diff --git a/gcc/gcc.c b/gcc/gcc.c
index c0eb3c10cfd..a57a3d0aec4 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -1077,7 +1077,7 @@ proper position among the other output files. */
LINK_PLUGIN_SPEC \
"%{flto|flto=*:%<fcompare-debug*} \
%{flto} %{fno-lto} %{flto=*} %l " LINK_PIE_SPEC \
- "%{fuse-ld=*:-fuse-ld=%*} " LINK_COMPRESS_DEBUG_SPEC \
+ "%{fuse-ld=*:-fuse-ld=%*} %{fld-path=*:-fld-path=%*} "
LINK_COMPRESS_DEBUG_SPEC \
"%X %{o*} %{e*} %{N} %{n} %{r}\
%{s} %{t} %{u*} %{z} %{Z} %{!nostdlib:%{!r:%{!nostartfiles:%S}}} \
%{static|no-pie|static-pie:} %@{L*} %(mfwrap) %(link_libgcc) " \
diff --git a/gcc/opts.c b/gcc/opts.c
index 340d99434b3..c4507d53abc 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -2750,6 +2750,7 @@ common_handle_option (struct gcc_options *opts,
case OPT_fuse_ld_bfd:
case OPT_fuse_ld_gold:
case OPT_fuse_ld_lld:
+ case OPT_fld_path_:
case OPT_fuse_linker_plugin:
/* No-op. Used by the driver and passed to us because it starts with f.*/
break;
--
2.27.0.383.g050319c2ae-goog
