437215 - XPIDL cross compile config error

Status: RESOLVED INVALID

(Firefox Build System :: General, defect)

Description

[Bo Yang]

Attachment: Patch to disable building target xpidl when we are not building for WINCE

Now, in cross compile, we did not create the target xpidl file.  This is written in the file:

xpcom/typelib/xpidl/Makefile.in

like following:

# Cross-compiling

# Don't build xpidl for the target.  This is not intended to be a permanent
# solution.  It's necessary because it is presently difficult to build
# xpidl's prerequisites (libIDL and glib) as fat and suitable for a cross.
# This will be fixed.  -mm

But when I make a cross compile on Linux for mingw32, the build system start to make a target xpidl because some of the wrong Makefile.in config. And this patch is used to repair it.

Comment 1

[Benjamin Smedberg]

Comment on attachment 323715 [details] [diff] [review]
Patch to disable building target xpidl when we are not building for WINCE

Hrm. Normally when cross-compiling you should have the target libidl/glib as well as the host libidl/glib... is that not the case? That way we will produce both a target xpidl binary as well as a host host_xpidl binary.

Comment 2

[Bo Yang]

(In reply to comment #1)
> (From update of attachment 323715 [details] [diff] [review])
> Hrm. Normally when cross-compiling you should have the target libidl/glib as
> well as the host libidl/glib... is that not the case? That way we will produce
> both a target xpidl binary as well as a host host_xpidl binary.
> 

Yeah, but the comment said, we will do this later. Maybe it is time to do this. We need both host and target xpidl. I think I can figure out a solution, can I take this bug?

Comment 3

[Benjamin Smedberg]

So, there are people who cross-compile for mingw already without this change, so I don't understand why any change at all is required.

Comment 4

[Bo Yang]

(In reply to comment #3)
> So, there are people who cross-compile for mingw already without this change,
> so I don't understand why any change at all is required.

En, I have cross-compiled Mozilla with Mingw without this change, too. But I need to set some LIBIDL_CFLAGS and LDFLAGS evn variables to make the cross-compiler to find the right headers and libraries of libIDL and glib for the target platform. And I think that is just a workaround. 
And, I don't find any document/manual about cross-compiling mingw. Could you please give me some URLs about how to cross-compile with mingw if you have seen? Thanks very much!

Comment 5

[Benjamin Smedberg]

http://www.mozilla.org/build/cross-compiling.html has the general cross-compiling instructions. Important is the section about "Cross-compile glib, libIDL & gtk+"

Assuming you have cross-compiling enabled properly, configure should be setting HOST_LIBIDL_CFLAGS and HOST_LIBIDL_LIBS separately from LIBIDL_CFLAGS and LIBIDL_LIBS, see the configure block at http://mxr.mozilla.org/mozilla/source/configure.in#7210

Comment 6

[Benjamin Smedberg]

Comment on attachment 323715 [details] [diff] [review]
Patch to disable building target xpidl when we are not building for WINCE

You're welcome to hack this locally if that unblocks other work, but I don't think it's correct.

Comment 7

[Bo Yang]

(In reply to comment #5)
> http://www.mozilla.org/build/cross-compiling.html has the general
> cross-compiling instructions. Important is the section about "Cross-compile
> glib, libIDL & gtk+"
> Assuming you have cross-compiling enabled properly, configure should be setting
> HOST_LIBIDL_CFLAGS and HOST_LIBIDL_LIBS separately from LIBIDL_CFLAGS and
> LIBIDL_LIBS, see the configure block at
> http://mxr.mozilla.org/mozilla/source/configure.in#7210
> 

I still feel there is something wrong in two place. 
One is at xpcom/typelib/xpidl/Makefile.in:

At http://mxr.mozilla.org/mozilla/source/xpcom/typelib/xpidl/Makefile.in#47, it said it will compile a Program for non-WINCE platform whether we are cross-compiling or not. 
But at http://mxr.mozilla.org/mozilla/source/xpcom/typelib/xpidl/Makefile.in#97, it said we will not produe an XPIDL for target platform, so the following code http://mxr.mozilla.org/mozilla/source/xpcom/typelib/xpidl/Makefile.in#105 set the PROGRAM to NULL. 
I think the above two parts of code are conflicting to each other. The result is for non-WINCE platform, we always has a target XPIDL compiled whether we are cross-compiling. And this absolutely conflicts with the the comments at http://mxr.mozilla.org/mozilla/source/xpcom/typelib/xpidl/Makefile.in#97. 
And I think, my patch will remove the conflict and make sure there is no target XPIDL produced when cross-compiling. Just like the the comment said. So, I think maybe the comment should be removed or there is a logic confilt here.

The second one is at the configure.in.
From your reply, I think you must want both the HOST and TARGET XPIDL to compiled when cross-compiling. And I think that should be this case, too. And, compiling target XPIDL needs the libIDL/glib for the target platform. I can use LIBIDL_CFLAGS to set the headers of the target platform's libIDL/glib. But I find the LIBIDL_LIBS did not work at all.I mean, by adding a LIBIDL_LIBS in .mozconfig file, it affect nothing to the compiling progress. I think it is better to make sure the two VAR are all workable. And further more, I think specifying where to find the target platform's libIDL/glib headers and libs through configure's options may be better than just set the env variables. How do you think about this?

Comment 8

[cls]

Regarding the first problem, you're comparing 2 platform-specific assignments that do not apply to this case.  For WINCE (line 47), building xpidl is disabled for the target platform due to WINCE-specific compiler issue.  For Darwin/OSX (line 97), building xpidl is also disabled for the target due to the reasons listed in the Makefile.

Regarding the second problem, the default scenario when cross-compiling is to build both the host & target versions of xpidl.  A properly configured mingw32 cross-compiled build will already do this.  I believe your specific build issues come from setting LIBIDL_CFLAGS/LIBS in .config rather than setting LIBIDL_CONFIG and using the -config scripts.  While setting those variable may work sometimes, configure was designed to use the -config script (or pkg-config output) when possible so it's very likely that configure is overriding the settings from the .mozconfig.  When cross-compiling, you will need to specify HOST_LIBIDL_CONFIG as the cross-compiling document states.