[PATCH v3] winegcc: Implement -Wl,--out-implib

Kevin Puetz PuetzKevinA at JohnDeere.com
Wed Nov 25 13:41:43 CST 2020


This allows a CMake toolchain (or other caller) to treat winegcc like MinGW,
specifying that it produce a separate file for imports, e.g.

set(CMAKE_IMPORT_LIBRARY_PREFIX lib)
set(CMAKE_IMPORT_LIBRARY_SUFFIX .a)
string(APPEND CMAKE_C_CREATE_SHARED_LIBRARY " -Wl,--out-implib,<TARGET_IMPLIB>")

Signed-off-by: Kevin Puetz <PuetzKevinA at JohnDeere.com>
---
makedep.c isn't changed to use use this because the few cases in which wine
currently uses #pragma implib (and thus winebuild --implib) involve
putting some (but not all) of the object files into the libfoo.a as well.

The motive is to fix our CMake toolchain for wineg++ to support using
target_link_libraries to link other SHARED_LIBRARY targets in the project.
This broke when wine-5.7 removed __wine_spec_init from winecrt0; the issue
is that CMake links to with an absolute path to the .so (i.e. foo.dll.so).
So we had been (unnnoticed until it quit working) getting an ELF DT_NEEDED
instead of a PE import. This "worked" before, since __wine_spec_init
would still register the builtin dll loaded in such a fashion. Now the
dependency's own dllimports (from kernel32, etc) don't get loaded anymore.
And I'm pretty sure it only worked before by happy accident.

CMake supports windows-style DLL/implib separation, but it really wants
the link rule to produce both artifacts (as MSVC/MinGW do) and the implib
needs to be a file that can be passed to linking as an absolute path.
And (for least surprise) it seems like that filename should work with -lfoo
too, even though CMake will always pass a full path. libfoo.def doesn't,
because winegcc sees libfoo.def as the spec_file (i.e. --export). The only
way I could find to pass a libfoo.def file and have it be imports (besides
having winegcc find it via -lfoo) was to conceal it in -Wb,libfoo.def,
which feels rather hacky.

Just forwarding the mingw-style -Wl,--out-implib to winebuild --implib
seemed easy and MinGW-like (which winegcc often seems to aim for).
add_undef_import is subtle, but it's already there (for #pragma implib)
so I didn't see any a reason to prefer a libfoo.def over a libfoo.a,
when the latter already works as a filename and as -lfoo.

If I've overlooked some reason it's preferable to use .def files, perhaps
there could be a distinct extension (.impdef, .a.def, or .lib ala MSVC?)
which get_file_type treats as file_dll and guess_lib_type (also?) searches.
Then --out-implib could check the extension and use winebuild --def
vs winebuild --implib accordingly (like how winegcc already reacts to the
extension of -o to decide between generate_app_loader, --fake, etc).

Signed-off-by in the sense that I think this is correct and adequate,
but I'm happy to take feedback if there's other use-cases an upstream
submission should try to address...
---
 tools/winegcc/winegcc.c      | 39 +++++++++++++++++++++++++++++++++++-
 tools/winegcc/winegcc.man.in |  3 +++
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/tools/winegcc/winegcc.c b/tools/winegcc/winegcc.c
index 9268a5dfd1d..e9707a73774 100644
--- a/tools/winegcc/winegcc.c
+++ b/tools/winegcc/winegcc.c
@@ -141,6 +141,7 @@ static const char* app_loader_template =
 
 static const char *output_file_name;
 static const char *output_debug_file;
+static const char *output_implib;
 static int keep_generated = 0;
 static strarray* tmp_files;
 #ifdef HAVE_SIGSET_T
@@ -231,6 +232,7 @@ struct options
     const char* entry_point;
     const char* prelink;
     const char* debug_file;
+    const char* out_implib;
     strarray* prefix;
     strarray* lib_dirs;
     strarray* args;
@@ -273,6 +275,7 @@ static void cleanup_output_files(void)
 {
     if (output_file_name) unlink( output_file_name );
     if (output_debug_file) unlink( output_debug_file );
+    if (output_implib) unlink( output_implib );
 }
 
 static void clean_temp_files(void)
@@ -522,6 +525,9 @@ static strarray *get_link_args( struct options *opts, const char *output_name )
         if (opts->debug_file && strendswith(opts->debug_file, ".pdb"))
             strarray_add(link_args, strmake("-Wl,-pdb,%s", opts->debug_file));
 
+        if (opts->out_implib)
+            strarray_add(link_args, strmake("-Wl,--out-implib,%s", opts->out_implib));
+
         if (!try_link( opts->prefix, link_args, "-Wl,--file-alignment,0x1000" ))
             strarray_add( link_args, strmake( "-Wl,--file-alignment,%s",
                                               opts->file_align ? opts->file_align : "0x1000" ));
@@ -554,6 +560,10 @@ static strarray *get_link_args( struct options *opts, const char *output_name )
             strarray_add(link_args, "-Wl,-debug");
             strarray_add(link_args, strmake("-Wl,-pdb:%s", opts->debug_file));
         }
+
+        if (opts->out_implib)
+            strarray_add(link_args, strmake("-Wl,-implib:%s", opts->out_implib));
+
         else if (!opts->strip)
             strarray_add(link_args, "-Wl,-debug:dwarf");
         strarray_add( link_args, strmake( "-Wl,-filealign:%s", opts->file_align ? opts->file_align : "0x1000" ));
@@ -1085,7 +1095,7 @@ static void add_library( struct options *opts, strarray *lib_dirs, strarray *fil
 static void build(struct options* opts)
 {
     strarray *lib_dirs, *files;
-    strarray *spec_args, *link_args, *tool;
+    strarray *spec_args, *link_args, *implib_args, *tool;
     char *output_file, *output_path;
     const char *spec_o_name, *libgcc = NULL;
     const char *output_name, *spec_file, *lang;
@@ -1430,6 +1440,7 @@ static void build(struct options* opts)
 
     output_file_name = output_path;
     output_debug_file = opts->debug_file;
+    output_implib = opts->out_implib;
     atexit( cleanup_output_files );
 
     spawn(opts->prefix, link_args, 0);
@@ -1460,6 +1471,26 @@ static void build(struct options* opts)
         strarray_free(tool);
     }
 
+    if (opts->out_implib && !is_pe)
+    {
+        if (!spec_file)
+            error("--out-implib requires a .spec or .def file\n");
+
+        implib_args = get_winebuild_args( opts );
+        if ((tool = build_tool_name( opts, TOOL_CC ))) strarray_add( implib_args, strmake( "--cc-cmd=%s", strarray_tostring( tool, " " )));
+        if ((tool = build_tool_name( opts, TOOL_LD ))) strarray_add( implib_args, strmake( "--ld-cmd=%s", strarray_tostring( tool, " " )));
+
+        strarray_add(implib_args, "--implib");
+        strarray_add(implib_args, "-o");
+        strarray_add(implib_args, opts->out_implib);
+        strarray_add(implib_args, "--export");
+        strarray_add(implib_args, spec_file);
+        strarray_addall(implib_args, opts->winebuild_args);
+
+        spawn(opts->prefix, implib_args, 0);
+        strarray_free (implib_args);
+    }
+
     /* set the base address with prelink if linker support is not present */
     if (opts->prelink && !opts->target)
     {
@@ -1972,6 +2003,11 @@ int main(int argc, char **argv)
                                 strarray_add( opts.files, strmake( "-Wl,%s", Wl->base[j] ));
                                 continue;
                             }
+                            if (!strcmp(Wl->base[j], "--out-implib"))
+                            {
+                                opts.out_implib = strdup( Wl->base[++j] );
+                                continue;
+                            }
                             if (!strcmp(Wl->base[j], "-static")) linking = -1;
                             strarray_add(opts.linker_args, strmake("-Wl,%s",Wl->base[j]));
                         }
@@ -2056,5 +2092,6 @@ int main(int argc, char **argv)
 
     output_file_name = NULL;
     output_debug_file = NULL;
+    output_implib = NULL;
     return 0;
 }
diff --git a/tools/winegcc/winegcc.man.in b/tools/winegcc/winegcc.man.in
index 8a14dd59fd1..5ee1456fed9 100644
--- a/tools/winegcc/winegcc.man.in
+++ b/tools/winegcc/winegcc.man.in
@@ -72,6 +72,9 @@ Do not add the winecrt0 library when linking.
 .IP \fB-Wb,\fIoption\fR
 Pass an option to winebuild.  If \fIoption\fR contains
 commas, it is split into multiple options at the commas.
+.IP "\fB-b,--target \fItarget\fR"
+.IP "\fB-Wl,--out-implib,\fIlib.a\fR"
+This option should be used while linking a dll. \fBwinebuild --implib\fR is used for non-PE targets whose linker does not natively have such an option, so a \fIlib.spec\fR or \fIlib.def\fR is required.
 .SH ENVIRONMENT
 .TP
 .B WINEBUILD
-- 
2.29.2




More information about the wine-devel mailing list