[glibc/maskray/lld] configure: Allow LD to be LLD 13.0.0 or above [BZ #26558]

[Fangrui Song <maskray@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c658d24e55609b16d8a0129e6cee617663d49caf

commit c658d24e55609b16d8a0129e6cee617663d49caf
Author: Fangrui Song <maskray@google.com>
Date:   Thu Aug 5 09:11:21 2021 -0700

    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).
    
    With BZ #28153 (glibc bug exposed by testing with LLD) fixed,
    `make check` only has 2 more failures with LLD than with GNU ld:
    BZ #28154 (LLD follows the PowerPC port of GNU ld for ifunc by
    placing IRELATIVE relocations in .rela.dyn).
    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
    (ISTM non-default version symbols are changed to default versions
    by a version script).
    
    ---
    
    I identified the lack of support of
    
    * version script on non-default version symbols
    * copy relocations on non-default version symbols
    
    in an earlier snapshot of LLD 13.0.0 and fixed them.
    The functionality of the LLD linked libc.so and ld.so looks pretty good.

Diff:
---
 configure    | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 configure.ac | 20 ++++++++++++----
 2 files changed, 88 insertions(+), 9 deletions(-)

diff --git a/configure b/configure
index 9b966196d4..050f1a29cf 100755
--- a/configure
+++ b/configure
@@ -4664,9 +4664,10 @@ if test $ac_verc_fail = yes; then
 fi
 
 
-if test -n "`$LD --version | sed -n 's/^GNU \(gold\).*$/\1/p'`"; then
+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 +4730,75 @@ 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 :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$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
-  for ac_prog in $LD
+  # 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
+
+    ;;
+  *)
+    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 +4861,8 @@ if test $ac_verc_fail = yes; then
   LD=: critic_missing="$critic_missing GNU ld"
 fi
 
-fi
+    ;;
+esac
 
 # These programs are version sensitive.
 for ac_prog in gnumake gmake make
diff --git a/configure.ac b/configure.ac
index 17a4c9a1ab..5632277f9c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -995,18 +995,28 @@ AC_CHECK_PROG_VER(AS, $AS, --version,
 		  [2.1[0-9][0-9]*|2.2[5-9]*|2.[3-9][0-9]*|[3-9].*|[1-9][0-9]*],
 		  AS=: critic_missing="$critic_missing as")
 
-if test -n "`$LD --version | sed -n 's/^GNU \(gold\).*$/\1/p'`"; then
+case $($LD --version) in
+  "GNU gold"*)
   # Accept gold 1.14 or higher
-  AC_CHECK_PROG_VER(LD, $LD, --version,
+    AC_CHECK_PROG_VER(LD, $LD, --version,
 		    [GNU gold.* \([0-9][0-9]*\.[0-9.]*\)],
 		    [1.1[4-9]*|1.[2-9][0-9]*|1.1[0-9][0-9]*|[2-9].*|[1-9][0-9]*],
 		    LD=: critic_missing="$critic_missing GNU gold")
-else
-  AC_CHECK_PROG_VER(LD, $LD, --version,
+    ;;
+  "LLD"*)
+  # Accept LLD 13.0.0 or higher
+    AC_CHECK_PROG_VER(LD, $LD, --version,
+		    [LLD.* \([0-9][0-9]*\.[0-9.]*\)],
+		    [1[3-9].*|[2-9][0-9].*],
+		    LD=: critic_missing="$critic_missing LLD")
+    ;;
+  *)
+    AC_CHECK_PROG_VER(LD, $LD, --version,
 		    [GNU ld.* \([0-9][0-9]*\.[0-9.]*\)],
 		    [2.1[0-9][0-9]*|2.2[5-9]*|2.[3-9][0-9]*|[3-9].*|[1-9][0-9]*],
 		    LD=: critic_missing="$critic_missing GNU ld")
-fi
+    ;;
+esac
 
 # These programs are version sensitive.
 AC_CHECK_PROG_VER(MAKE, gnumake gmake make, --version,