On Wed, Nov 28, 2012 at 8:18 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
>
> Binutils supports 2 linkers, ld.gold and ld.bfd. One of them is
> configured as the default linker, ld, which is used by GCC. Sometimes,
> we want to use the alternate linker with GCC at run-time. This patch
> adds -fuse-ld=bfd and -fuse-ld=gold options to GCC driver. It changes
> collect2.c to pick either ld.bfd or ld.gold. It also adds
> ORIGINAL_LD_BFD_FOR_TARGET and ORIGINAL_LD_GOLD_FOR_TARGET to
> exec-tool.in to add -fuse-ld=bfd and -fuse-ld=gold support to
> collect-ld. Since ld.bfd nor ld.gold know the new options, you
> will get
>
> # ./xgcc -B./ /tmp/x.c -fuse-ld=gold -v
> ...
> ./collect-ld --eh-frame-hdr -m elf_x86_64 -dynamic-linker
> /lib64/ld-linux-x86-64.so.2 -fuse-ld=gold /lib/../lib64/crt1.o
> /lib/../lib64/crti.o ./crtbegin.o -L. -L/lib/../lib64 -L/usr/lib/../lib64
> /tmp/cclVWcGz.o -v -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc
> --as-needed -lgcc_s --no-as-needed ./crtend.o /lib/../lib64/crtn.o
> GNU gold (Linux/GNU Binutils 2.23.51.0.7.20121127) 1.11
> /usr/local/bin/ld.gold: fatal error: -f/--auxiliary may not be used without
> -shared
> collect2: error: ld returned 1 exit status
>
> This is because we pass everything to ld and ld.bfd/ld.gold doesn't
> understand -fuse-ld=bfd/-fuse-ld=gold. It isn't a problem for collect2
> since it will filter-out -fuse-ld=bfd/-fuse-ld=gold. I will submit a
> binutils patch to ignore -fuse-ld=bfd/-fuse-ld=gold, similar to -flto
> options.
>
> OK to install?
>
> Thanks.
>
>
> H.J.
> ---
> 2012-11-28 Nick Clifton <ni...@redhat.com>
> Matthias Klose <d...@debian.org>
> Doug Kwan <dougk...@google.com>
> H.J. Lu <hongjiu...@intel.com>
>
> PR driver/55470
> * collect2.c (main): Support -fuse-ld=bfd and -fuse-ld=gold.
>
> * common.opt: Add fuse-ld=bfd and fuse-ld=gold.
>
> * gcc.c (LINK_COMMAND_SPEC): Pass -fuse-ld=* to collect2.
>
> * opts.c (comman_handle_option): Ignore -fuse-ld=bfd and
> -fuse-ld=gold.
>
> * doc/invoke.texi: Document -fuse-ld=bfd and -fuse-ld=gold.
Here is the minimum patch for 4.8. OK to install?
--
H.J.
---
diff --git a/gcc/collect2.c b/gcc/collect2.c
index 49c4030..4e8cdf0 100644
--- a/gcc/collect2.c
+++ b/gcc/collect2.c
@@ -842,8 +842,21 @@ maybe_run_lto_and_relink (char **lto_ld_argv,
char **object_lst,
int
main (int argc, char **argv)
{
- static const char *const ld_suffix = "ld";
- static const char *const plugin_ld_suffix = PLUGIN_LD_SUFFIX;
+ enum linker_select
+ {
+ USE_DEFAULT_LD,
+ USE_PLUGIN_LD,
+ USE_GOLD_LD,
+ USE_BFD_LD,
+ USE_LD_MAX
+ } selected_linker = USE_DEFAULT_LD;
+ static const char *const ld_suffixes[USE_LD_MAX] =
+ {
+ "ld",
+ PLUGIN_LD_SUFFIX,
+ "ld.gold",
+ "ld.bfd"
+ };
static const char *const real_ld_suffix = "real-ld";
static const char *const collect_ld_suffix = "collect-ld";
static const char *const nm_suffix = "nm";
@@ -854,16 +867,13 @@ main (int argc, char **argv)
static const char *const strip_suffix = "strip";
static const char *const gstrip_suffix = "gstrip";
+ const char *full_ld_suffixes[USE_LD_MAX];
#ifdef CROSS_DIRECTORY_STRUCTURE
/* If we look for a program in the compiler directories, we just use
the short name, since these directories are already system-specific.
But it we look for a program in the system directories, we need to
qualify the program name with the target machine. */
- const char *const full_ld_suffix =
- concat(target_machine, "-", ld_suffix, NULL);
- const char *const full_plugin_ld_suffix =
- concat(target_machine, "-", plugin_ld_suffix, NULL);
const char *const full_nm_suffix =
concat (target_machine, "-", nm_suffix, NULL);
const char *const full_gnm_suffix =
@@ -877,13 +887,11 @@ main (int argc, char **argv)
const char *const full_gstrip_suffix =
concat (target_machine, "-", gstrip_suffix, NULL);
#else
- const char *const full_ld_suffix = ld_suffix;
- const char *const full_plugin_ld_suffix = plugin_ld_suffix;
- const char *const full_nm_suffix = nm_suffix;
- const char *const full_gnm_suffix = gnm_suffix;
#ifdef LDD_SUFFIX
const char *const full_ldd_suffix = ldd_suffix;
#endif
+ const char *const full_nm_suffix = nm_suffix;
+ const char *const full_gnm_suffix = gnm_suffix;
const char *const full_strip_suffix = strip_suffix;
const char *const full_gstrip_suffix = gstrip_suffix;
#endif /* CROSS_DIRECTORY_STRUCTURE */
@@ -900,6 +908,7 @@ main (int argc, char **argv)
char **ld1_argv;
const char **ld1;
bool use_plugin = false;
+ bool use_collect_ld = false;
/* 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
@@ -919,6 +928,15 @@ main (int argc, char **argv)
int first_file;
int num_c_args;
char **old_argv;
+ int i;
+
+ for (i = 0; i < USE_LD_MAX; i++)
+ full_ld_suffixes[i]
+#ifdef CROSS_DIRECTORY_STRUCTURE
+ = concat(target_machine, "-", ld_suffixes[i], NULL);
+#else
+ = ld_suffixes[i];
+#endif
p = argv[0] + strlen (argv[0]);
while (p != argv[0] && !IS_DIR_SEPARATOR (p[-1]))
@@ -980,7 +998,6 @@ main (int argc, char **argv)
are called. We also look for the -flto or -flto-partition=none
flag to know
what LTO mode we are in. */
{
- int i;
bool no_partition = false;
for (i = 1; argv[i] != NULL; i ++)
@@ -998,7 +1015,14 @@ main (int argc, char **argv)
{
use_plugin = true;
lto_mode = LTO_MODE_NONE;
+ 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;
+
#ifdef COLLECT_EXPORT_LIST
/* since -brtl, -bexport, -b64 are not position dependent
also check for them here */
@@ -1095,21 +1119,18 @@ main (int argc, char **argv)
ld_file_name = find_a_file (&cpath, real_ld_suffix);
/* Likewise for `collect-ld'. */
if (ld_file_name == 0)
- ld_file_name = find_a_file (&cpath, collect_ld_suffix);
+ {
+ ld_file_name = find_a_file (&cpath, collect_ld_suffix);
+ 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,
- use_plugin
- ? plugin_ld_suffix
- : ld_suffix);
+ ld_file_name = find_a_file (&cpath, ld_suffixes[selected_linker]);
/* 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,
- use_plugin
- ? full_plugin_ld_suffix
- : full_ld_suffix);
+ ld_file_name = find_a_file (&path, full_ld_suffixes[selected_linker]);
#ifdef REAL_NM_FILE_NAME
nm_file_name = find_a_file (&path, REAL_NM_FILE_NAME);
@@ -1266,6 +1287,13 @@ main (int argc, char **argv)
"configuration");
#endif
}
+ else if (!use_collect_ld
+ && strncmp (arg, "-fuse-ld=", 9) == 0)
+ {
+ /* Do not pass -fuse-ld={bfd|gold} to the linker. */
+ ld1--;
+ ld2--;
+ }
#ifdef TARGET_AIX_VERSION
else
{
diff --git a/gcc/common.opt b/gcc/common.opt
index 4c8bd11..7b36ba3 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2171,6 +2171,12 @@ funwind-tables
Common Report Var(flag_unwind_tables) Optimization
Just generate unwind tables for exception handling
+fuse-ld=bfd
+Common Var(flag_use_ld_bfd) Negative(fuse-ld=gold) Undocumented
+
+fuse-ld=gold
+Common Var(flag_use_ld_gold) Negative(fuse-ld=bfd) Undocumented
+
fuse-linker-plugin
Common Undocumented
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 51b6e85..3558f43 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -425,7 +425,7 @@ Objective-C and Objective-C++ Dialects}.
-funit-at-a-time -funroll-all-loops -funroll-loops @gol
-funsafe-loop-optimizations -funsafe-math-optimizations -funswitch-loops @gol
-fvariable-expansion-in-unroller -fvect-cost-model -fvpt -fweb @gol
--fwhole-program -fwpa -fuse-linker-plugin @gol
+-fwhole-program -fwpa -fuse-ld=@var{linker} -fuse-linker-plugin @gol
--param @var{name}=@var{value}
-O -O0 -O1 -O2 -O3 -Os -Ofast -Og}
@@ -8419,6 +8419,12 @@ the comparison operation before register
allocation is complete.
Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+@item -fuse-ld=gold
+Use the @command{gold} linker instead of the default linker.
+
+@item -fuse-ld=bfd
+Use the @command{ld.bfd} linker instead of the default linker.
+
@item -fcprop-registers
@opindex fcprop-registers
After register allocation and post-register allocation instruction splitting,
diff --git a/gcc/gcc.c b/gcc/gcc.c
index 13e93e5..e0fee40 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -705,7 +705,8 @@ proper position among the other output files. */
LINK_PLUGIN_SPEC \
"%{flto|flto=*:%<fcompare-debug*} \
%{flto} %{flto=*} %l " LINK_PIE_SPEC \
- "%X %{o*} %{e*} %{N} %{n} %{r}\
+ "%{fuse-ld=*:-fuse-ld=%*}\
+ %X %{o*} %{e*} %{N} %{n} %{r}\
%{s} %{t} %{u*} %{z} %{Z} %{!nostdlib:%{!nostartfiles:%S}}\
%{static:} %{L*} %(mfwrap) %(link_libgcc) %o\
%{fopenmp|ftree-parallelize-loops=*:%:include(libgomp.spec)%(link_gomp)}\
diff --git a/gcc/opts.c b/gcc/opts.c
index b3a9afe..ff1b51e 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -1753,6 +1753,8 @@ common_handle_option (struct gcc_options *opts,
dc->max_errors = value;
break;
+ case OPT_fuse_ld_bfd:
+ case OPT_fuse_ld_gold:
case OPT_fuse_linker_plugin:
/* No-op. Used by the driver and passed to us because it starts with f.*/
break;
