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NuxiNL / cloudlibc

CloudABI's standard C library
BSD 2-Clause "Simplified" License
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CMake having trouble finding sprintf / stdio.h #24

Closed mcandre closed 5 years ago

mcandre commented 5 years ago

Hey, I'm glad to report mild success with CloudABI, building some very simple C and Rust apps! Unfortunately, when I try to use sprintf, I'm getting build errors. Am I doing something wrong?

Source

My "issue-115" branch of my tonixxx project, in the examples/fewer C project directory:

https://github.com/mcandre/tonixxx/tree/issue-115/examples/fewer

Trace (Ubuntu)

$ CC=x86_64-unknown-cloudabi-cc CXX=x86_64-unknown-cloudabi-c++ cmake .
$ cmake --build . --config Release
[ 33%] Linking C executable bin/fewer
/usr/bin/x86_64-unknown-cloudabi-ld: error: undefined symbol: sprintf
>>> referenced by fewer.c
>>>               CMakeFiles/fewer.dir/lib/fewer.c.o:(render_boi)
clang: error: linker command failed with exit code 1 (use -v to see invocation)
CMakeFiles/fewer.dir/build.make:120: recipe for target 'bin/fewer' failed
make[2]: *** [bin/fewer] Error 1
CMakeFiles/Makefile2:227: recipe for target 'CMakeFiles/fewer.dir/all' failed
make[1]: *** [CMakeFiles/fewer.dir/all] Error 2
Makefile:94: recipe for target 'all' failed
make: *** [all] Error 2

This is weird, as I am able to access other cloudlibc entities such as dprintf() and fopen() just fine in my main.c source file. Perhaps cmake is getting confused about where libc comes from when dealing with the separate file fewer.c?

Note: I am running these commands from an Ubuntu 18.04 Bionic Beaver instance in VirtualBox on macOS. When I try to build this CMake project directly on my macOS host, I can't even get the initial CMake cache to complete:

Trace (macOS)

$ CC=x86_64-unknown-cloudabi-cc CXX=x86_64-unknown-cloudabi-c++ cmake .
-- The C compiler identification is Clang 6.0.0
-- The CXX compiler identification is Clang 6.0.0
-- Check for working C compiler: /usr/local/bin/x86_64-unknown-cloudabi-cc
-- Check for working C compiler: /usr/local/bin/x86_64-unknown-cloudabi-cc -- broken
CMake Error at /usr/local/Cellar/cmake/3.13.2/share/cmake/Modules/CMakeTestCCompiler.cmake:52 (message):
  The C compiler

    "/usr/local/bin/x86_64-unknown-cloudabi-cc"

  is not able to compile a simple test program.

  It fails with the following output:

    Change Dir: /Users/andrew/go/src/github.com/mcandre/tonixxx/examples/fewer/CMakeFiles/CMakeTmp

    Run Build Command:"/usr/local/bin/gmake" "cmTC_9b5a3/fast"
    /usr/local/bin/gmake -f CMakeFiles/cmTC_9b5a3.dir/build.make CMakeFiles/cmTC_9b5a3.dir/build
    gmake[1]: Entering directory '/Users/andrew/go/src/github.com/mcandre/tonixxx/examples/fewer/CMakeFiles/CMakeTmp'
    Building C object CMakeFiles/cmTC_9b5a3.dir/testCCompiler.c.o
    /usr/local/bin/x86_64-unknown-cloudabi-cc    -o CMakeFiles/cmTC_9b5a3.dir/testCCompiler.c.o   -c /Users/andrew/go/src/github.com/mcandre/tonixxx/examples/fewer/CMakeFiles/CMakeTmp/testCCompiler.c
    Linking C executable cmTC_9b5a3
    /usr/local/Cellar/cmake/3.13.2/bin/cmake -E cmake_link_script CMakeFiles/cmTC_9b5a3.dir/link.txt --verbose=1
    /usr/local/bin/x86_64-unknown-cloudabi-cc   -Wl,-search_paths_first -Wl,-headerpad_max_install_names   CMakeFiles/cmTC_9b5a3.dir/testCCompiler.c.o  -o cmTC_9b5a3 
    /usr/local/bin/x86_64-unknown-cloudabi-ld: error: unknown argument: -search_paths_first
    clang-6.0: error: linker command failed with exit code 1 (use -v to see invocation)
    gmake[1]: *** [CMakeFiles/cmTC_9b5a3.dir/build.make:87: cmTC_9b5a3] Error 1
    gmake[1]: Leaving directory '/Users/andrew/go/src/github.com/mcandre/tonixxx/examples/fewer/CMakeFiles/CMakeTmp'
    gmake: *** [Makefile:121: cmTC_9b5a3/fast] Error 2

  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  CMakeLists.txt:3 (project)

Update

I spent some more time configuring my CMakeLists.txt so that the compiler options are closer to the cloudabi compiler defaults, but I am still getting this strange error. Clearly, fewer.c is #includeing the <stdio.h> file, so I am scratching my head wondering what part of this system is dropping the ball.

One thing I've noticed is that cmake tends to compile executables in multiple stages, compared to using x86_64-unknown-cloudabi-cc directly. Perhaps the compiler is dropping information about where libraries are defined, when object files are built and linked, versus building an executable all at once?

mcandre commented 5 years ago

Ah, sprintf() is there but feature gated. When I replace that call with snprintf(), then everything compiles!