MantisBT - CMake
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IDProjectCategoryView StatusDate SubmittedLast Update
0015650CMakeCMakepublic2015-07-14 07:072016-06-10 14:31
ReporterAbigail 
Assigned ToKitware Robot 
PrioritynormalSeveritymajorReproducibilityalways
StatusclosedResolutionmoved 
PlatformApple MacOSMac OS XOS Version10.10.3
Product VersionCMake 3.2.3 
Target VersionFixed in Version 
Summary0015650: Linking large files on OS X can result in linker failing with "command line too long" error
DescriptionWhen a project contains sufficiently many source files - the one I'm compiling has 1689 .cpp files - the linker will fail, with the message "Error running link command: Argument list too long".

When using response lists (via set(CMAKE_CXX_USE_RESPONSE_FILE_FOR_OBJECTS 1)), the issue still occurs. This is because the response file is specified as a linker flag with @ResponseFile.rsp syntax, which is expanded by the compiler driver rather than being passed through and then expanded internally by the linker.

OS X's linker, ld64, doesn't support the @ResponseFile.rsp syntax, so it's not possible to work around this with set(CMAKE_CXX_RESPONSE_FILE_LINK_FLAG "-Wl,@"). However, it does support -filelist, but this requires the file to be newline-separated rather than space-separated.
Steps To ReproduceIn an empty directory:

for i in {0000..9999}; echo "void f$i() {}" >> $i.c
find . > files.txt
cat << EOF > CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
project(long_file_test)
file(STRINGS "files.txt" files)
add_executable(long_file_test ${files})
EOF
cmake . && cmake --build . -- -j 24

...This will compile everything correctly, and then at the end emit:

[100%] Linking C executable long_file_test
Error running link command: Argument list too long
make[2]: *** [long_file_test] Error 2
make[1]: *** [CMakeFiles/long_file_test.dir/all] Error 2
make: *** [all] Error 2
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Issue History
Date ModifiedUsernameFieldChange
2015-07-14 07:07AbigailNew Issue
2015-07-14 09:19AbigailNote Added: 0039136
2015-07-14 09:38Brad KingNote Added: 0039137
2016-06-10 14:29Kitware RobotNote Added: 0042808
2016-06-10 14:29Kitware RobotStatusnew => resolved
2016-06-10 14:29Kitware RobotResolutionopen => moved
2016-06-10 14:29Kitware RobotAssigned To => Kitware Robot
2016-06-10 14:31Kitware RobotStatusresolved => closed

Notes
(0039136)
Abigail   
2015-07-14 09:19   
I've compiled a patched version with a fix/workaround - the needed changes are https://github.com/AbigailBuccaneer/CMake/commit/0c6ff4e4c3e95adbcee65f716d31a2fba69a7539 [^]

With this, I can then use:

if(APPLE)
    set(CMAKE_CXX_USE_RESPONSE_FILE_FOR_OBJECTS 1)
    set(CMAKE_CXX_RESPONSE_FILE_LINK_FLAG "-Wl,-filelist,")
    set(CMAKE_CXX_OBJECT_RESPONSE_FILE_SEPARATOR "\n")
endif()

in my CMake file and successfully link the project.

However, these settings should presumably be set in a standard CMake module based on whether the linker is ld64 or not, and I've not yet investigated where to set them.
(0039137)
Brad King   
2015-07-14 09:38   
Re 0015650:0039136: Thanks! Indeed those should be set by the platform modules rather than project code. Look at "Modules/Platform/Darwin-{Clang,GNU,Intel}.cmake" for adding them.
(0042808)
Kitware Robot   
2016-06-10 14:29   
Resolving issue as `moved`.

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