Using cmake with an alternate toolchain

[dbry]

Since there have been numerous changes to the cmake stuff here, including the ability to build the winamp plugin for Window using mingw, I thought I would experiment with this (if for no other reason to test the generated winamp plugin and see if it actually works). I have mingw installed and use it to generate Windows executables all the time (by itself, or with Autotools to build WavPack), so I thought this would be fairly straightforward.

Initially I had no idea how to start so I Googled and found this page. I tried that and got pretty far, but it fails with both mingw versions here:

Performing C SOURCE FILE Test COMPILER_SUPPORTS_SYMBOL_MAPS failed with the following compile output:
Change Dir: /home/david/WavPack/build/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/make cmTC_be63c/fast && /usr/bin/make -f CMakeFiles/cmTC_be63c.dir/build.make CMakeFiles/cmTC_be63c.dir/build
make[1]: Entering directory '/home/david/WavPack/build/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_be63c.dir/src.c.obj
/usr/bin/x86_64-w64-mingw32-gcc   -DCOMPILER_SUPPORTS_SYMBOL_MAPS -Wl,--version-script=/home/david/WavPack/build//CMakeFiles/conftest.map   -o CMakeFiles/cmTC_be63c.dir/src.c.obj   -c /home/david/WavPack/build/CMakeFiles/CMakeTmp/src.c
Linking C executable cmTC_be63c.exe
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTC_be63c.dir/link.txt --verbose=1
/usr/bin/cmake -E remove -f CMakeFiles/cmTC_be63c.dir/objects.a
/usr/bin/x86_64-w64-mingw32-ar cr CMakeFiles/cmTC_be63c.dir/objects.a @CMakeFiles/cmTC_be63c.dir/objects1.rsp
/usr/bin/x86_64-w64-mingw32-gcc  -DCOMPILER_SUPPORTS_SYMBOL_MAPS -Wl,--version-script=/home/david/WavPack/build//CMakeFiles/conftest.map    -Wl,--whole-archive CMakeFiles/cmTC_be63c.dir/objects.a -Wl,--no-whole-archive  -o cmTC_be63c.exe -Wl,--out-implib,libcmTC_be63c.dll.a -Wl,--major-image-version,0,--minor-image-version,0 @CMakeFiles/cmTC_be63c.dir/linklibs.rsp
/usr/bin/x86_64-w64-mingw32-ld:/home/david/WavPack/build//CMakeFiles/conftest.map:8: ignoring invalid character `\' in script
make[1]: Leaving directory '/home/david/WavPack/build/CMakeFiles/CMakeTmp'

Figuring Google would rescue me again I Googled COMPILER_SUPPORTS_SYMBOL_MAPS but found to my surprise that the only place on the whole Internet where that string exists is my CMakeLists.txt, which of course means I'm stuck.

Could anyone kindly put me on the right track? @evpobr @sezero

Also, is there an easy way to switch to clang?

Thanks!

[evpobr]

WavPack/CMakeLists.txt

Line 353 in ce01373

check_c_linker_flag("-Wl,--version-script=${PROJECT_BINARY_DIR}/${CMAKE_FILES_DIRECTORY}/conftest.map" COMPILER_SUPPORTS_SYMBOL_MAPS)

It checks -Wl,--version-script linker flag. I suspect that MinGW GCC does not support this.

Actually correct path is:

WavPack/CMakeLists.txt

Line 330 in ce01373

if(BUILD_SHARED_LIBS AND (WIN32 OR CYGWIN))

I am almost one hundred percent sure that this should work with MinGW on Windows.

[evpobr]

/usr/bin/x86_64-w64-mingw32-ld:/home/david/WavPack/build//CMakeFiles/conftest.map:8: ignoring invalid character `' in script

This is also very strange.

[evpobr]

Run Build Command(s):/usr/bin/make

Also this is strange. Not sure it is correct version. Maybe something is not installed.

[evpobr]

Probably generator must be MinGW Makefiles.

[sezero]

found this page.

For what it's worth, this is my toolchain file for cross-compilation purposes:

SET(CMAKE_SYSTEM_NAME Windows)

SET(CMAKE_C_COMPILER /opt/cross_win64/bin/x86_64-w64-mingw32-gcc)
SET(CMAKE_CXX_COMPILER /opt/cross_win64/bin/x86_64-w64-mingw32-g++)
SET(CMAKE_RC_COMPILER /opt/cross_win64/bin/x86_64-w64-mingw32-windres)

# where is the target environment
SET(CMAKE_FIND_ROOT_PATH /opt/cross_win64 /opt/cross_win64/x86_64-w64-mingw32)

# adjust the default behaviour of the FIND_XXX() commands:
# search headers and libraries in the target environment, search
# programs in the host environment
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

WavPack/CMakeLists.txt

Line 353 in ce01373

check_c_linker_flag("-Wl,--version-script=${PROJECT_BINARY_DIR}/${CMAKE_FILES_DIRECTORY}/conftest.map" COMPILER_SUPPORTS_SYMBOL_MAPS)

It checks -Wl,--version-script linker flag. I suspect that MinGW GCC does not support this.

It actually should, if I remember correctly

[snipping other stuff]

Could anyone kindly put me on the right track?

I am mentioned, but I don't speak and not proficient in cmake, I don't
like cmake, I detest cmake, [append more here ...]

I don't know whether he'd be interested in, but @madebr did quite a lot
of cmake work in SDL projects, and he is proficient.

[madebr]

The error is about an invalid stray \ in conftest.map

/usr/bin/x86_64-w64-mingw32-ld:/home/david/WavPack/build//CMakeFiles/conftest.map:8: ignoring invalid character `\' in script

This file is generated here:

WavPack/CMakeLists.txt

Lines 351 to 352 in ce01373

	set(CONFTTEST_CONTENTS "VERS_1 {\n global: sym\;\n\n};\n\nVERS_2 {\n global: sym;\n} VERS_1\;")
	file(WRITE ${PROJECT_BINARY_DIR}/${CMAKE_FILES_DIRECTORY}/conftest.map "${CONFTTEST_CONTENTS}")

I ran these 2 lines locally, and it generated

VERS_1 {
    global: sym\;

};

VERS_2 {
    global: sym;
} VERS_1\;

which looks incorrect.

The string should not escape the semicolons.
When fixing this, perhaps also add a final newline.

[sezero]

Interestingly, the generated map file I get has no stray \ characters on my linux.
cmake version is 3.9.6, if that matters.

[madebr]

No idea why that's happening.
I just downloaded a CMake 3.9.6 binary,
created /tmp/a.cmake with:

set(CONFTTEST_CONTENTS "VERS_1 {\n    global: sym\;\n\n};\n\nVERS_2 {\n    global: sym;\n} VERS_1\;")
file(WRITE conftest.map "${CONFTTEST_CONTENTS}")

And ran:

cmake -P /tmp/a.cmake

Both 3.9.6 and my system CMake 3.24.2 generated the same conftest.map.

[sezero]

In any case, removal of escaping semicolons should not hurt.

[madebr]

No, the escape is only needed when you need to embed a semicolon as member of a list.
I verified without any escape and it worked on both 3.9.6 and 3.22.4.

[sezero]

So, the following is a go? (I couldn't make it to emit the missing newline to end, though.)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 597efac..5bd290f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -350,3 +350,3 @@ elseif(CMAKE_SYSTEM_NAME MATCHES "Darwin")
 else()
-    set(CONFTTEST_CONTENTS "VERS_1 {\n    global: sym\;\n\n};\n\nVERS_2 {\n    global: sym;\n} VERS_1\;")
+    set(CONFTTEST_CONTENTS "VERS_1 {\n    global: sym;\n\n};\n\nVERS_2 {\n    global: sym;\n} VERS_1;")
     file(WRITE ${PROJECT_BINARY_DIR}/${CMAKE_FILES_DIRECTORY}/conftest.map "${CONFTTEST_CONTENTS}")

[sezero]

Off-topic to this ticket: would the existing wavpack cmake'ry work when embedding in other projects? I.e.: I might cook wavpack support to our SDL_mixer (hopefully soon (TM)).

[dbry]

I believe that embedding in other projects was part of the original intent. WavPack was recently added to Audacity, and I believe that's how they did it (but really have only a passing knowledge).

On-topic, the fix above eliminates the warning message (which occurs with regular CC also). However, apparently it wasn't the cause of the error return. It still fails there, this time with no syntax warning message:

Performing C SOURCE FILE Test COMPILER_SUPPORTS_SYMBOL_MAPS failed with the following compile output:
Change Dir: /home/david/WavPack/build/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/make cmTC_48e24/fast && /usr/bin/make -f CMakeFiles/cmTC_48e24.dir/build.make CMakeFiles/cmTC_48e24.dir/build
make[1]: Entering directory '/home/david/WavPack/build/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_48e24.dir/src.c.obj
/usr/bin/i686-w64-mingw32-gcc   -DCOMPILER_SUPPORTS_SYMBOL_MAPS -Wl,--version-script=/home/david/WavPack/build//CMakeFiles/conftest.map   -o CMakeFiles/cmTC_48e24.dir/src.c.obj   -c /home/david/WavPack/build/CMakeFiles/CMakeTmp/src.c
Linking C executable cmTC_48e24.exe
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTC_48e24.dir/link.txt --verbose=1
/usr/bin/cmake -E remove -f CMakeFiles/cmTC_48e24.dir/objects.a
/usr/bin/i686-w64-mingw32-ar cr CMakeFiles/cmTC_48e24.dir/objects.a @CMakeFiles/cmTC_48e24.dir/objects1.rsp
/usr/bin/i686-w64-mingw32-gcc  -DCOMPILER_SUPPORTS_SYMBOL_MAPS -Wl,--version-script=/home/david/WavPack/build//CMakeFiles/conftest.map    -Wl,--whole-archive CMakeFiles/cmTC_48e24.dir/objects.a -Wl,--no-whole-archive  -o cmTC_48e24.exe -Wl,--out-implib,libcmTC_48e24.dll.a -Wl,--major-image-version,0,--minor-image-version,0 @CMakeFiles/cmTC_48e24.dir/linklibs.rsp
make[1]: Leaving directory '/home/david/WavPack/build/CMakeFiles/CMakeTmp'

So @sezero , I assume this step passes in your setup? I thought this would be easy considering that you were doing basically the same thing, but it's certainly not critical to what I'm doing (I still use Autotools for day-to-day work).

Thanks @madebr and @evpobr !

[madebr]

FILE_CONTENTS is also handled weird. It's a string, which is appended as a cmake list.
CMake has string(APPEND), but not in cmake 3.2.

I'll fork and take a looksy.

[madebr]

With #147, I can build wavpack targeting Linux and MinGW, on my Linux machine.