libtool-patches
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH 1/2] Use POSIX nm to simplify AIX export_symbols_cmds.


From: David Edelsohn
Subject: Re: [PATCH 1/2] Use POSIX nm to simplify AIX export_symbols_cmds.
Date: Mon, 21 Mar 2016 10:47:49 -0400

On Mon, Mar 21, 2016 at 4:49 AM, Michael Haubenwallner
<address@hidden> wrote:
>
> On 03/20/2016 01:04 AM, David Edelsohn wrote:
>> I agree with this in principle, but I'm not convinced that the patch
>> itself is correct.
>
> Thanks!
>
>> I also would have split the MS-compatible part of the patch as a
>> separate step.  It is not listed in the ChangeLog and just confuses
>> the patch.
>
> This is just a reordering of existing code - these lines are removed
> below, and the ChangeLog part is "Reorder to allow for platform specific
> hooks during transformation of global_symbol_pipe into C source code."
>
>> I don't see that this emits TLS symbols.  Global TLS symbols are not
>> in the symcode list.
>
> Isn't the "L" for TLS symbols?
>
> +    symcode='[[BDLTVWZ]]'

Sorry, I was confused by the two cases for "aix" and the case for
"GNU" within AIX.

>
> But indeed I've failed to identify the symcode of "weak TLS" symbols,
> except for "L*" with AIX nm in unspecified mode (nm -l, no -B or -P)
> Neither AIX nm nor GNU nm docs explicitly tell about weak TLS symbols.
> Is it possible for TLS symbols to be weak at all?
>
>> Global symbol pipe and exclude symbols somehow restricts the symbols
>> to the non "dot" symbols?
>
> Yes - but this is what the existing code does as well:
> '... && ([substr](\$ 1,1,1) != ".") ..'

Is that in your patch or existing code?  Your patch removes the
current substr($3,1,1).

>
>> The export_symbols_cmds awk command does not have matching quotes, so
>> I don't know what is going on.
>>
>> awk '\''{ kw = "" } /^[[VWZ]] / { kw = " weak" } { print $ 3 kw }'\''
>>
>> you're starting and ending with '\" which seems odd. why aren't these
>> complementary?
>
> The awk argument is passed between ['], as it contains ["].
> Escaping [\] the ['] is done outside any other string. Read as:
> _LT_TAGVAR(...)=['$NM ... | awk '][\']['{ ... }'][\'][' | sort ...']
> Indeed I can add [] here if you like.

Ah, well, this is turning into a very complex statement.  GCC requires
GNU Awk and most developers use Bash, but does this work correctly
with AIX awk and AIX Ksh?

Thanks, David

>
> Thanks!
> /haubi/
>
>>
>> Thanks, David
>>
>> On Wed, Mar 2, 2016 at 11:19 AM, Michael Haubenwallner
>> <address@hidden> wrote:
>>> * m4/libtool.m4 (LT_PATH_NM): Detect POSIX-compatible nm for AIX.  In
>>> BSD mode, the AIX nm does not tell whether a symbol is weak, need to use
>>> POSIX mode instead.
>>> (_LT_CMD_GLOBAL_SYMBOLS): Support POSIX-compatible nm.  Reorder to allow
>>> for platform specific hooks during transformation of global_symbol_pipe
>>> into C source code.  For AIX, set hook to transform even weak text
>>> symbols as text symbols.
>>> (_LT_LINKER_SHLIBS): Use global_symbol_pipe to simplify forming the
>>> export_symbols_cmds for AIX.
>>> ---
>>>  m4/libtool.m4 | 101 
>>> ++++++++++++++++++++++++++++++++--------------------------
>>>  1 file changed, 55 insertions(+), 46 deletions(-)
>>>
>>> diff --git a/m4/libtool.m4 b/m4/libtool.m4
>>> index 2c0e657..6134522 100644
>>> --- a/m4/libtool.m4
>>> +++ b/m4/libtool.m4
>>> @@ -3755,10 +3755,10 @@ _LT_DECL([], [want_nocaseglob], [1],
>>>
>>>  # LT_PATH_NM
>>>  # ----------
>>> -# find the pathname to a BSD- or MS-compatible name lister
>>> +# find the pathname to a BSD-, POSIX- or MS-compatible name lister
>>>  AC_DEFUN([LT_PATH_NM],
>>>  [AC_REQUIRE([AC_PROG_CC])dnl
>>> -AC_CACHE_CHECK([for BSD- or MS-compatible name lister (nm)], lt_cv_path_NM,
>>> +AC_CACHE_CHECK([for BSD-, POSIX- or MS-compatible name lister (nm)], 
>>> lt_cv_path_NM,
>>>  [if test -n "$NM"; the
>>>    # Let the user override the test.
>>>    lt_cv_path_NM=$NM
>>> @@ -3808,6 +3808,26 @@ else
>>>    : ${lt_cv_path_NM=no}
>>>  fi])
>>>  if test no != "$lt_cv_path_NM"; then
>>> +  case $host_os in
>>> +  aix[[4-9]]*)
>>> +    # With AIX nm we need the '-l' flag to get the "weak" information
>>> +    # for the Import File, but '-l' is ignored with the '-B' flag.  So
>>> +    # we use the '-P' (POSIX) flag instead.  As users often provide the
>>> +    # '-B' flag, which conflicts with '-P', we drop any provided flag.
>>> +    # AIX nm needs the '-C' flag to disable demangling.  For both GNU
>>> +    # and AIX nm, the '-g' flag shows public (global) symbols only,
>>> +    # and the '-p' flag disables sorting to improve performance.
>>> +    set dummy $lt_cv_path_NM
>>> +    case address@hidden|@2 -V 2>&1` in
>>> +    *GNU* | *'with BFD'*)
>>> +      lt_cv_path_NM="@S|@2 -Bgp"
>>> +      ;;
>>> +    *)
>>> +      lt_cv_path_NM="@S|@2 -PlCgp"
>>> +      ;;
>>> +    esac
>>> +    ;;
>>> +  esac
>>>    NM=$lt_cv_path_NM
>>>  else
>>>    # Didn't find any BSD compatible name lister, look for dumpbin.
>>> @@ -3832,7 +3852,7 @@ fi
>>>  test -z "$NM" && NM=nm
>>>  _LT_SET_TOOL_ABI_FLAG([NM])
>>>  AC_SUBST([NM])
>>> -_LT_DECL([], [NM], [1], [A BSD- or MS-compatible name lister])dnl
>>> +_LT_DECL([], [NM], [1], [A BSD-, POSIX- or MS-compatible name lister])dnl
>>>
>>>  AC_CACHE_CHECK([the name lister ($NM) interface], [lt_cv_nm_interface],
>>>    [lt_cv_nm_interface="BSD nm"
>>> @@ -3847,6 +3867,8 @@ AC_CACHE_CHECK([the name lister ($NM) interface], 
>>> [lt_cv_nm_interface],
>>>    cat conftest.out >&AS_MESSAGE_LOG_FD
>>>    if $GREP 'External.*some_variable' conftest.out > /dev/null; then
>>>      lt_cv_nm_interface="MS dumpbin"
>>> +  elif $GREP '^[[       ]]*_*some_variable' conftest.out > /dev/null; then
>>> +    lt_cv_nm_interface="POSIX nm"
>>>    fi
>>>    rm -f conftest*])
>>>  ])# LT_PATH_NM
>>> @@ -4012,8 +4034,33 @@ symcode='[[BCDEGRST]]'
>>>  # Regexp to match symbols that can be accessed directly from C.
>>>  sympat='\([[_A-Za-z]][[_A-Za-z0-9]]*\)'
>>>
>>> +if test "$lt_cv_nm_interface" = "MS dumpbin"; then
>>> +  # Gets list of data symbols to import.
>>> +  lt_cv_sys_global_symbol_to_import="sed -n -e 's/^I .* \(.*\)$/\1/p'"
>>> +  # Adjust the below global symbol transforms to fixup imported variables.
>>> +  lt_cdecl_hook=" -e 's/^I .* \(.*\)$/extern __declspec(dllimport) char 
>>> \1;/p'"
>>> +  lt_c_name_hook=" -e 's/^I .* \(.*\)$/  {\"\1\", (void *) 0},/p'"
>>> +  lt_c_name_lib_hook="\
>>> +  -e 's/^I .* \(lib.*\)$/  {\"\1\", (void *) 0},/p'\
>>> +  -e 's/^I .* \(.*\)$/  {\"lib\1\", (void *) 0},/p'"
>>> +else
>>> +  # Disable hooks by default.
>>> +  lt_cv_sys_global_symbol_to_import=
>>> +  lt_cdecl_hook=
>>> +  lt_c_name_hook=
>>> +  lt_c_name_lib_hook=
>>> +fi
>>> +
>>>  # Define system-specific variables.
>>>  case $host_os in
>>> +aix[[4-9]]*)
>>> +  case `$NM -V 2>&1` in
>>> +  *GNU* | *'with BFD'*) ;;
>>> +  *)
>>> +    symcode='[[BDLTVWZ]]'
>>> +    lt_cdecl_hook=" -e 's/^W/T/p'" # weak text symbol
>>> +  esac
>>> +  ;;
>>>  aix*)
>>>    symcode='[[BCDT]]'
>>>    ;;
>>> @@ -4054,23 +4101,6 @@ case `$NM -V 2>&1` in
>>>    symcode='[[ABCDGIRSTW]]' ;;
>>>  esac
>>>
>>> -if test "$lt_cv_nm_interface" = "MS dumpbin"; then
>>> -  # Gets list of data symbols to import.
>>> -  lt_cv_sys_global_symbol_to_import="sed -n -e 's/^I .* \(.*\)$/\1/p'"
>>> -  # Adjust the below global symbol transforms to fixup imported variables.
>>> -  lt_cdecl_hook=" -e 's/^I .* \(.*\)$/extern __declspec(dllimport) char 
>>> \1;/p'"
>>> -  lt_c_name_hook=" -e 's/^I .* \(.*\)$/  {\"\1\", (void *) 0},/p'"
>>> -  lt_c_name_lib_hook="\
>>> -  -e 's/^I .* \(lib.*\)$/  {\"\1\", (void *) 0},/p'\
>>> -  -e 's/^I .* \(.*\)$/  {\"lib\1\", (void *) 0},/p'"
>>> -else
>>> -  # Disable hooks by default.
>>> -  lt_cv_sys_global_symbol_to_import=
>>> -  lt_cdecl_hook=
>>> -  lt_c_name_hook=
>>> -  lt_c_name_lib_hook=
>>> -fi
>>> -
>>>  # Transform an extracted symbol line into a proper C declaration.
>>>  # Some systems (esp. on ia64) link data and code symbols differently,
>>>  # so use this general approach.
>>> @@ -4128,6 +4158,9 @@ for ac_symprfx in "" "_"; do
>>>  "     s[1]~/address@hidden/{print f,s[1],s[1]; next};"\
>>>  "     s[1]~prfx {split(s[1],t,\"@\"); print 
>>> f,t[1],substr(t[1],length(prfx))}"\
>>>  "     ' prfx=^$ac_symprfx]"
>>> +  elif test "$lt_cv_nm_interface" = "POSIX nm"; then
>>> +    symxfrm="\\2 $ac_symprfx\\1 \\1"
>>> +    lt_cv_sys_global_symbol_pipe="sed -n -e 's/^[[      
>>> ]]*$ac_symprfx$sympat[[         ]][[    ]]*\($symcode$symcode*\)[[      
>>> ]][[    ]]*.*$opt_cr$/$symxfrm/p'"
>>>    else
>>>      lt_cv_sys_global_symbol_pipe="sed -n -e 's/^.*[[    
>>> ]]\($symcode$symcode*\)[[       ]][[    
>>> ]]*$ac_symprfx$sympat$opt_cr$/$symxfrm/p'"
>>>    fi
>>> @@ -5009,19 +5042,7 @@ m4_if([$1], [CXX], [
>>>    _LT_TAGVAR(exclude_expsyms, 
>>> $1)=['_GLOBAL_OFFSET_TABLE_|_GLOBAL__F[ID]_.*']
>>>    case $host_os in
>>>    aix[[4-9]]*)
>>> -    # If we're using GNU nm, then we don't want the "-C" option.
>>> -    # -C means demangle to GNU nm, but means don't demangle to AIX nm.
>>> -    # Without the "-l" option, or with the "-B" option, AIX nm treats
>>> -    # weak defined symbols like other global defined symbols, whereas
>>> -    # GNU nm marks them as "W".
>>> -    # While the 'weak' keyword is ignored in the Export File, we need
>>> -    # it in the Import File for the 'aix-soname' feature, so we have
>>> -    # to replace the "-B" option with "-P" for AIX nm.
>>> -    if $NM -V 2>&1 | $GREP 'GNU' > /dev/null; then
>>> -      _LT_TAGVAR(export_symbols_cmds, $1)='$NM -Bpg $libobjs $convenience 
>>> | awk '\''{ if (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == "B") || (\$ 2 
>>> == "W")) && ([substr](\$ 3,1,1) != ".")) { if (\$ 2 == "W") { print \$ 3 " 
>>> weak" } else { print \$ 3 } } }'\'' | sort -u > $export_symbols'
>>> -    else
>>> -      _LT_TAGVAR(export_symbols_cmds, $1)='`func_echo_all $NM | $SED -e 
>>> '\''s/B\([[^B]]*\)$/P\1/'\''` -PCpgl $libobjs $convenience | awk '\''{ if 
>>> (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == "B") || (\$ 2 == "L") || (\$ 2 
>>> == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) && ([substr](\$ 1,1,1) != ".")) 
>>> { if ((\$ 2 == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) { print \$ 1 " weak" 
>>> } else { print \$ 1 } } }'\'' | sort -u > $export_symbols'
>>> -    fi
>>> +    _LT_TAGVAR(export_symbols_cmds, $1)='$NM $libobjs $convenience | 
>>> $global_symbol_pipe | $EGREP -v " ($exclude_expsyms)$" | awk '\''{ kw = "" 
>>> } /^[[VWZ]] / { kw = " weak" } { print $ 3 kw }'\'' | sort -u > 
>>> $export_symbols'
>>>      ;;
>>>    pw32*)
>>>      _LT_TAGVAR(export_symbols_cmds, $1)=$ltdll_cmds
>>> @@ -5464,19 +5485,7 @@ _LT_EOF
>>>         exp_sym_flag='-Bexport'
>>>         no_entry_flag=
>>>        else
>>> -       # If we're using GNU nm, then we don't want the "-C" option.
>>> -       # -C means demangle to GNU nm, but means don't demangle to AIX nm.
>>> -       # Without the "-l" option, or with the "-B" option, AIX nm treats
>>> -       # weak defined symbols like other global defined symbols, whereas
>>> -       # GNU nm marks them as "W".
>>> -       # While the 'weak' keyword is ignored in the Export File, we need
>>> -       # it in the Import File for the 'aix-soname' feature, so we have
>>> -       # to replace the "-B" option with "-P" for AIX nm.
>>> -       if $NM -V 2>&1 | $GREP 'GNU' > /dev/null; then
>>> -         _LT_TAGVAR(export_symbols_cmds, $1)='$NM -Bpg $libobjs 
>>> $convenience | awk '\''{ if (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == 
>>> "B") || (\$ 2 == "W")) && ([substr](\$ 3,1,1) != ".")) { if (\$ 2 == "W") { 
>>> print \$ 3 " weak" } else { print \$ 3 } } }'\'' | sort -u > 
>>> $export_symbols'
>>> -       else
>>> -         _LT_TAGVAR(export_symbols_cmds, $1)='`func_echo_all $NM | $SED -e 
>>> '\''s/B\([[^B]]*\)$/P\1/'\''` -PCpgl $libobjs $convenience | awk '\''{ if 
>>> (((\$ 2 == "T") || (\$ 2 == "D") || (\$ 2 == "B") || (\$ 2 == "L") || (\$ 2 
>>> == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) && ([substr](\$ 1,1,1) != ".")) 
>>> { if ((\$ 2 == "W") || (\$ 2 == "V") || (\$ 2 == "Z")) { print \$ 1 " weak" 
>>> } else { print \$ 1 } } }'\'' | sort -u > $export_symbols'
>>> -       fi
>>> +       _LT_TAGVAR(export_symbols_cmds, $1)='$NM $libobjs $convenience | 
>>> $global_symbol_pipe | $EGREP -v " ($exclude_expsyms)$" | awk '\''{ kw = "" 
>>> } /^[[VWZ]] / { kw = " weak" } { print $ 3 kw }'\'' | sort -u > 
>>> $export_symbols'
>>>         aix_use_runtimelinking=no
>>>
>>>         # Test if we are trying to use run time linking or normal
>>> --
>>> 2.4.6
>>>



reply via email to

[Prev in Thread] Current Thread [Next in Thread]