Re: [PATCH] [cygwin|mingw] fix dlpreopen with --disable-static

[Charles Wilson]

Ralf Wildenhues wrote:
>> The point is, we perhaps STARTED with the .la file, but the whole point
>> of the dlpreopen $pass is to replace each .la file in $dlprefiles with
>> the name of the object from which the symbols should be extracted, to
>> build the symbol table. So, pick one: either the DLL, or the import
>> library (there is no static lib, the failure mode in question occurs
>> when --disable-static).
>>
>> If you pick "DLL" -- then it's real hard to get the symbols (objdump
>> ugliness, plus figuring out which ones are DATA).
>>
>> If you pick "implib" -- then it's real hard to get the correct DLL name
>> (but not nearly as hard as extracting the correct symbols from the dll).
>>
>> But the name of the .la file is no longer available.
> 
> But that's a problem that can be solved.
> 
> # turn $1 into a string suitable for a shell variable name
> func_tr_sh ()
> {
>  ... # typically forks, except maybe with bash ${var/subst/repl}
> }
> 
> # when treating $dlprefile, save the corresponding .la file name:
> func_tr_sh "$dlprefile"
> eval "libfile_$tr_sh_result=\$corresponding_dotla_file"
> 
> # later, when searching for the .la file, test libfile$tr_sh_result
> # for contents
> 
> What do you think?

That would work. But it only gets rid of the grotty "find the name of
the DLL given the implib" problem -- which is not a small thing, of course.

But that presupposes that my change to the dlpreopen $pass, where on
cygwin|mingw we replace the la file in the $dlprefiles list with the
implib, stands. Did I convince you we needed this bit:

-         elif test -n "$dlname"; then
-           newdlprefiles="$newdlprefiles $dir/$dlname"
+         # Except on mingw|cygwin, where we must use the import library,
+         # so lt_dlopen is handled in another way
          else
-           newdlprefiles="$newdlprefiles $dir/$linklib"
+           case "$host" in
+             *cygwin* | *mingw* )
+               newdlprefiles="$newdlprefiles $dir/$linklib"
+                ;;
+             * )
+               if test -n "$dlname"; then
+                 newdlprefiles="$newdlprefiles $dir/$dlname"
+               else
+                 newdlprefiles="$newdlprefiles $dir/$linklib"
+               fi
+                ;;
+           esac

If so, then I guess the other code section would look like

     func_verbose "extracting global C symbols from \`$dlprefile'"
     func_basename "$dlprefile"
     name="$func_basename_result"
-    $opt_dry_run || {
-      eval '$ECHO ": $name " >> "$nlist"'
-      eval "$NM $dlprefile 2>/dev/null | $global_symbol_pipe >> '$nlist'"
-    }
+    case $host in
+      *cygwin | *mingw* )
+        # if an import library, we need to obtain dlname
+        if func_win32_import_lib_p "$dlprefile"; then
+          func_tr_sh "$dlprefile"
+          eval "curr_lafile=\$libfile_$tr_sh_result"
+          $opt_dry_run || {
+            if test -n "$curr_lafile" && func_lalib_p "$curr_lafile"; then
+              # geez. does this need to happen in a subshell, to
+              # avoid clobbering our current variable values?
+              source "$curr_lafile"
+              if test -n "$dlname" ; then
+                func_basename "$dlname"
+                dlbasename="$func_basename_result"
+                eval '$ECHO ": $dlbasename" >> "$nlist"'
+              else
+                func_warning "Could not compute DLL name from $name"
+                eval '$ECHO ": $name " >> "$nlist"'
+              fi
+            else
+              func_warning "Could not determing .la name from $name"
+              eval '$ECHO ": $name " >> "$nlist"'
+            fi
+            eval "$NM $dlprefile 2>/dev/null | $global_symbol_pipe |
+              $SED -e '/I __imp/d' -e 's/I __nm_/D /;s/_nm__//' >>
'$nlist'"
+          }
+        else # not an import lib
+          $opt_dry_run || {
+          eval '$ECHO ": $name " >> "$nlist"'
+          eval "$NM $dlprefile 2>/dev/null | $global_symbol_pipe >>
'$nlist'"
+          }
+        fi
+        ;;
+      *)
etc.

Is that the idea?

--
Chuck