diff options
Diffstat (limited to 'm4/find_ld.m4')
| -rw-r--r-- | m4/find_ld.m4 | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/m4/find_ld.m4 b/m4/find_ld.m4 new file mode 100644 index 0000000000..a6b5c9c598 --- /dev/null +++ b/m4/find_ld.m4 @@ -0,0 +1,70 @@ +# FIND_LD +# --------- +# Find the version of `ld` to use and figure out how to get gcc to use it for +# linking (if --enable-ld-override is enabled). This is used in both in the top +# level configure.ac and in distrib/configure.ac.in. +# +# $1 = the platform +# $2 = the variable to set with GHC options to configure gcc to use the chosen linker +# +AC_DEFUN([FIND_LD],[ + AC_ARG_ENABLE(ld-override, + [AS_HELP_STRING([--disable-ld-override], + [Prevent GHC from overriding the default linker used by gcc. If ld-override is enabled GHC will try to tell gcc to use whichever linker is selected by the LD environment variable. [default=override enabled]])], + [], + [enable_ld_override=yes]) + + find_ld() { + # Make sure the user didn't specify LD manually. + if test "z$LD" != "z"; then + AC_CHECK_TARGET_TOOL([LD], [ld]) + return + fi + + # Manually iterate over possible names since we want to ensure that, e.g., + # if ld.lld is installed but gcc doesn't support -fuse-ld=lld, that we + # then still try ld.gold and -fuse-ld=gold. + for possible_ld in ld.lld ld.gold ld; do + TmpLd="" # In case the user set LD + AC_CHECK_TARGET_TOOL([TmpLd], [$possible_ld]) + if test "x$TmpLd" = "x"; then continue; fi + + out=`$TmpLd --version` + case $out in + "GNU ld"*) + FP_CC_LINKER_FLAG_TRY(bfd, $2) ;; + "GNU gold"*) + FP_CC_LINKER_FLAG_TRY(gold, $2) + if test "$cross_compiling" = "yes"; then + AC_MSG_NOTICE([Using ld.gold and assuming that it is not affected by binutils issue 22266]); + fi + ;; + "LLD"*) + FP_CC_LINKER_FLAG_TRY(lld, $2) ;; + *) AC_MSG_NOTICE([unknown linker version $out]) ;; + esac + if test "z$$2" = "z"; then + AC_MSG_NOTICE([unable to convince '$CC' to use linker '$TmpLd']) + # a terrible hack to prevent autoconf from caching the previous + # AC_CHECK_TARGET_TOOL result since next time we'll be looking + # for another ld variant. + $as_unset ac_cv_prog_ac_ct_TmpLd + else + LD="$TmpLd" + return + fi + done + + # Fallback + AC_CHECK_TARGET_TOOL([LD], [ld]) + } + + if test "x$enable_ld_override" = "xyes"; then + find_ld + else + AC_CHECK_TARGET_TOOL([LD], [ld]) + fi + + CHECK_LD_COPY_BUG([$1]) +]) + |