glibc/trunk/reenable_DT_HASH.patch

   1 From e47de5cb2d4dbecb58f569ed241e8e95c568f03c Mon Sep 17 00:00:00 2001
   2 From: Florian Weimer <fweimer@redhat.com>
   3 Date: Fri, 29 Apr 2022 16:37:51 +0200
   4 Subject: [PATCH] Do not use --hash-style=both for building glibc shared
   5  objects
   6
   7 The comment indicates that --hash-style=both was used to maintain
   8 compatibility with static dlopen, but we had many internal ABI
   9 changes since then, so this compatiblity does not add value anymore.
  10
  11 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
  12 ---
  13  Makeconfig     |  9 +++++++++
  14  Makerules      |  7 +++++++
  15  config.make.in |  1 +
  16  configure      | 28 ++++++++++++++++++++++++++++
  17  configure.ac   | 16 ++++++++++++++++
  18  5 files changed, 61 insertions(+)
  19
  20 diff --git b/Makeconfig a/Makeconfig
  21 index 760f14e92f..0aa5fb0099 100644
  22 --- b/Makeconfig
  23 +++ a/Makeconfig
  24 @@ -362,6 +362,15 @@ relro-LDFLAGS = -Wl,-z,relro
  25  LDFLAGS.so += $(relro-LDFLAGS)
  26  LDFLAGS-rtld += $(relro-LDFLAGS)
  27
  28 +ifeq (yes,$(have-hash-style))
  29 +# For the time being we unconditionally use 'both'.  At some time we
  30 +# should declare statically linked code as 'out of luck' and compile
  31 +# with --hash-style=gnu only.
  32 +hashstyle-LDFLAGS = -Wl,--hash-style=both
  33 +LDFLAGS.so += $(hashstyle-LDFLAGS)
  34 +LDFLAGS-rtld += $(hashstyle-LDFLAGS)
  35 +endif
  36 +
  37  ifeq (no,$(build-pie-default))
  38  pie-default = $(no-pie-ccflag)
  39  else # build-pie-default
  40 diff --git b/Makerules a/Makerules
  41 index 354528b8c7..428464f092 100644
  42 --- b/Makerules
  43 +++ a/Makerules
  44 @@ -557,6 +557,13 @@ $(common-objpfx)shlib.lds: $(common-objpfx)config.make $(..)Makerules
  45                   -Wl,--verbose 2>/dev/null | \
  46           sed > $@T \
  47               -e '/^=========/,/^=========/!d;/^=========/d' \
  48 +             $(if $(filter yes,$(have-hash-style)), \
  49 +                  -e 's/^.*\.gnu\.hash[        ]*:.*$$/  .note.ABI-tag : { *(.note.ABI-tag) } &/' \
  50 +                  -e '/^[      ]*\.hash[       ]*:.*$$/{h;d;}' \
  51 +                  -e '/DATA_SEGMENT_ALIGN/{H;g}' \
  52 +               , \
  53 +                  -e 's/^.*\.hash[     ]*:.*$$/  .note.ABI-tag : { *(.note.ABI-tag) } &/' \
  54 +              ) \
  55               -e 's/^.*\*(\.dynbss).*$$/& \
  56                  PROVIDE(__start___libc_freeres_ptrs = .); \
  57                  *(__libc_freeres_ptrs) \
  58 diff --git b/config.make.in a/config.make.in
  59 index fff4c78dd0..bf728c71c0 100644
  60 --- b/config.make.in
  61 +++ a/config.make.in
  62 @@ -70,6 +70,7 @@ have-libcap = @have_libcap@
  63  have-cc-with-libunwind = @libc_cv_cc_with_libunwind@
  64  fno-unit-at-a-time = @fno_unit_at_a_time@
  65  bind-now = @bindnow@
  66 +have-hash-style = @libc_cv_hashstyle@
  67  use-default-link = @use_default_link@
  68  have-cxx-thread_local = @libc_cv_cxx_thread_local@
  69  have-loop-to-function = @libc_cv_cc_loop_to_function@
  70 diff --git b/configure a/configure
  71 index 716dc041b6..5a730dc5fc 100755
  72 --- b/configure
  73 +++ a/configure
  74 @@ -622,6 +622,7 @@ libc_cv_cc_nofma
  75  libc_cv_mtls_dialect_gnu2
  76  fno_unit_at_a_time
  77  libc_cv_has_glob_dat
  78 +libc_cv_hashstyle
  79  libc_cv_fpie
  80  libc_cv_z_execstack
  81  ASFLAGS_config
  82 @@ -6193,6 +6194,33 @@ $as_echo "$libc_cv_fpie" >&6; }
  83
  84
  85
  86 +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for --hash-style option" >&5
  87 +$as_echo_n "checking for --hash-style option... " >&6; }
  88 +if ${libc_cv_hashstyle+:} false; then :
  89 +  $as_echo_n "(cached) " >&6
  90 +else
  91 +  cat > conftest.c <<EOF
  92 +int _start (void) { return 42; }
  93 +EOF
  94 +if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
  95 +                           -fPIC -shared -o conftest.so conftest.c
  96 +                           -Wl,--hash-style=both -nostdlib 1>&5'
  97 +  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
  98 +  (eval $ac_try) 2>&5
  99 +  ac_status=$?
 100 +  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
 101 +  test $ac_status = 0; }; }
 102 +then
 103 +  libc_cv_hashstyle=yes
 104 +else
 105 +  libc_cv_hashstyle=no
 106 +fi
 107 +rm -f conftest*
 108 +fi
 109 +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_hashstyle" >&5
 110 +$as_echo "$libc_cv_hashstyle" >&6; }
 111 +
 112 +
 113  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for GLOB_DAT reloc" >&5
 114  $as_echo_n "checking for GLOB_DAT reloc... " >&6; }
 115  if ${libc_cv_has_glob_dat+:} false; then :
 116 diff --git b/configure.ac a/configure.ac
 117 index d08ad4d64e..a045f6608e 100644
 118 --- b/configure.ac
 119 +++ a/configure.ac
 120 @@ -1360,6 +1360,22 @@ LIBC_TRY_CC_OPTION([-fpie], [libc_cv_fpie=yes], [libc_cv_fpie=no])
 121
 122  AC_SUBST(libc_cv_fpie)
 123
 124 +AC_CACHE_CHECK(for --hash-style option,
 125 +              libc_cv_hashstyle, [dnl
 126 +cat > conftest.c <<EOF
 127 +int _start (void) { return 42; }
 128 +EOF
 129 +if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
 130 +                           -fPIC -shared -o conftest.so conftest.c
 131 +                           -Wl,--hash-style=both -nostdlib 1>&AS_MESSAGE_LOG_FD])
 132 +then
 133 +  libc_cv_hashstyle=yes
 134 +else
 135 +  libc_cv_hashstyle=no
 136 +fi
 137 +rm -f conftest*])
 138 +AC_SUBST(libc_cv_hashstyle)
 139 +
 140  AC_CACHE_CHECK(for GLOB_DAT reloc,
 141                libc_cv_has_glob_dat, [dnl
 142  cat > conftest.c <<EOF
 143 --
 144 2.37.1
 145