git-x86_64-remove-pie-check

commit 115d242456de158e698ffb0f9a5fee3118e9e825
Author: Fangrui Song <maskray@google.com>
Date:   Thu Jul 8 14:26:22 2021 -0700

    x86_64: Remove unneeded static PIE check for undefined weak diagnostic

    https://sourceware.org/bugzilla/show_bug.cgi?id=21782 dropped an ld
    diagnostic for R_X86_64_PC32 referencing an undefined weak symbol in
    -pie links.  Arguably keeping the diagnostic like other ports is more
    correct, since statically resolving movl foo(%rip), %eax to the
    link-time zero address produces a corrupted output.

    It turns out that --enable-static-pie builds do not depend on the ld
    behavior. GCC generates GOT indirection for weak declarations for
    -fPIE/-fPIC, so what ld does with the PC-relative relocation doesn't
    really matter.

    Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Gbp-Pq: Topic amd64
Gbp-Pq: Name git-x86_64-remove-pie-check.diff

diff --git a/sysdeps/x86_64/configure b/sysdeps/x86_64/configure
index 84f82c24068ef04b9ea55ad9bdc92cf1a70da0cf..fc1840e23faaef644701d8fc481b55456034289f 100644 (file)
--- a/sysdeps/x86_64/configure
+++ b/sysdeps/x86_64/configure
@@ -107,39 +107,6 @@ if test x"$build_mathvec" = xnotset; then
   build_mathvec=yes
 fi
 
-if test "$static_pie" = yes; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for linker static PIE support" >&5
-$as_echo_n "checking for linker static PIE support... " >&6; }
-if ${libc_cv_ld_static_pie+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  cat > conftest.s <<\EOF
-       .text
-       .global _start
-       .weak foo
-_start:
-       leaq    foo(%rip), %rax
-EOF
-  libc_cv_pie_option="-Wl,-pie"
-  if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&5'
-  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; }; then
-    libc_cv_ld_static_pie=yes
-  else
-    libc_cv_ld_static_pie=no
-  fi
-rm -f conftest*
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_ld_static_pie" >&5
-$as_echo "$libc_cv_ld_static_pie" >&6; }
-  if test "$libc_cv_ld_static_pie" != yes; then
-    as_fn_error $? "linker support for static PIE needed" "$LINENO" 5
-  fi
-fi
-
 $as_echo "#define PI_STATIC_AND_HIDDEN 1" >>confdefs.h
 
 

diff --git a/sysdeps/x86_64/configure.ac b/sysdeps/x86_64/configure.ac
index cdaba0c075abfb2cca89d812cae32dd3e391dc16..611a7d9ba3fdfb8f1317e3713f695783745719d1 100644 (file)
--- a/sysdeps/x86_64/configure.ac
+++ b/sysdeps/x86_64/configure.ac
@@ -53,31 +53,6 @@ if test x"$build_mathvec" = xnotset; then
   build_mathvec=yes
 fi
 
-dnl Check if linker supports static PIE with the fix for
-dnl
-dnl https://sourceware.org/bugzilla/show_bug.cgi?id=21782
-dnl
-if test "$static_pie" = yes; then
-  AC_CACHE_CHECK(for linker static PIE support, libc_cv_ld_static_pie, [dnl
-cat > conftest.s <<\EOF
-       .text
-       .global _start
-       .weak foo
-_start:
-       leaq    foo(%rip), %rax
-EOF
-  libc_cv_pie_option="-Wl,-pie"
-  if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&AS_MESSAGE_LOG_FD); then
-    libc_cv_ld_static_pie=yes
-  else
-    libc_cv_ld_static_pie=no
-  fi
-rm -f conftest*])
-  if test "$libc_cv_ld_static_pie" != yes; then
-    AC_MSG_ERROR([linker support for static PIE needed])
-  fi
-fi
-
 dnl It is always possible to access static and hidden symbols in an
 dnl position independent way.
 AC_DEFINE(PI_STATIC_AND_HIDDEN)