configure: Allow LD to be LLD 13.0.0 or above [BZ #26558]

When using LLD (LLVM linker) as the linker, configure prints a confusing
message.

    *** These critical programs are missing or too old: GNU ld

LLD>=13.0.0 can build glibc --enable-static-pie. (8.0.0 needs one
workaround for -Wl,-defsym=_begin=0. 9.0.0 works with
--disable-static-pie).

XFAIL two tests sysdeps/x86/tst-ifunc-isa-* which have the BZ #28154
issue (LLD follows the PowerPC port of GNU ld for ifunc by placing
IRELATIVE relocations in .rela.dyn, triggering a glibc ifunc fragility).

The set of dynamic symbols is the same with GNU ld and LLD,
modulo unused SHN_ABS version node symbols.

For comparison, gold does not support --enable-static-pie
yet (--no-dynamic-linker is unsupported BZ #22221), yet
has 6 failures more than LLD. gold linked libc.so has
larger .dynsym differences with GNU ld and LLD
(non-default version symbols are changed to default versions
by a version script BZ #28196).

1 files changed, 77 insertions, 4 deletions

diff --git a/configure b/configure
index 61ff26487e..542802ad35 100755
--- a/configure
+++ b/configure
@@ -4664,9 +4664,11 @@ if test $ac_verc_fail = yes; then
 fi
 
 
-if test -n "`$LD --version | sed -n 's/^GNU \(gold\).*$/\1/p'`"; then
+libc_cv_with_lld=no
+case $($LD --version) in
+  "GNU gold"*)
   # Accept gold 1.14 or higher
-  for ac_prog in $LD
+    for ac_prog in $LD
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -4729,8 +4731,76 @@ if test $ac_verc_fail = yes; then
   LD=: critic_missing="$critic_missing GNU gold"
 fi
 
+    ;;
+  "LLD"*)
+  # Accept LLD 13.0.0 or higher
+    for ac_prog in $LD
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_LD+:} false; then :
+  $as_echo_n "(cached) " >&6
 else
-  for ac_prog in $LD
+  if test -n "$LD"; then
+  ac_cv_prog_LD="$LD" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
+    ac_cv_prog_LD="$ac_prog"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+LD=$ac_cv_prog_LD
+if test -n "$LD"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $LD" >&5
+$as_echo "$LD" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+  test -n "$LD" && break
+done
+
+if test -z "$LD"; then
+  ac_verc_fail=yes
+else
+  # Found it, now check the version.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking version of $LD" >&5
+$as_echo_n "checking version of $LD... " >&6; }
+  ac_prog_version=`$LD --version 2>&1 | sed -n 's/^.*LLD.* \([0-9][0-9]*\.[0-9.]*\).*$/\1/p'`
+  case $ac_prog_version in
+    '') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;
+    1[3-9].*|[2-9][0-9].*)
+       ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;
+    *) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;
+
+  esac
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_prog_version" >&5
+$as_echo "$ac_prog_version" >&6; }
+fi
+if test $ac_verc_fail = yes; then
+  LD=: critic_missing="$critic_missing LLD"
+fi
+
+    libc_cv_with_lld=yes
+    ;;
+  *)
+    for ac_prog in $LD
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -4793,7 +4863,10 @@ if test $ac_verc_fail = yes; then
   LD=: critic_missing="$critic_missing GNU ld"
 fi
 
-fi
+    ;;
+esac
+config_vars="$config_vars
+with-lld = $libc_cv_with_lld"
 
 # These programs are version sensitive.
 for ac_prog in gnumake gmake make