William A. Hoffman wrote:
At 05:11 PM 10/11/2006, Eran Guendelman wrote:
Hi, we are trying to track down why cmake 2.4 is crashing when generating the
VisualStudio 7 build files whereas cmake 2.2 worked fine. I built a debug
version of cmake and narrowed it down to the following issue:
In cmLocalGenerator::ComputeLinkInformation it goes through the libraries and
tries to add their information to the linkLibraries vector. It gets to a
library called xerces-c_2D. It checks whether this is a cmake target (using
FindTarget), and indeed finds that it is. So it then has the line
std::string linkItem = tgt->GetDirectory(0)
This is where the crash occurs, and the cause is as follows. In our build
environment, xerces-c_2D is built as a custom target (see below for why), so
its cmTarget::TargetType is UTILITY, and cmTarget::GetDirectory returns 0 in
this case. Hence trying to assign 0 to an std::string causes the crash.
Looking at cmTarget::GetDirectory, my instinct for "fixing" this is to change
default:
return 0;
to
default:
this->Directory = "";
so that the subsequent check of if(this->Directory.empty()) will take care of
this case. But then again, I don't really know anything about how this code is
supposed to work so this was just a guess (that at least did fix the crash and
succeeded in generating project files -- though I haven't tried to build them).
Anyway, as for why we use ADD_CUSTOM_TARGET to build xerces-c_2D, it's because
this is a third party library we are trying to build as part of our build
system, and since the library came with a VC7 .sln file but no CMakeLists.txt
files we basically made its CMakeLists.txt look something like:
ADD_CUSTOM_TARGET(xerces-c_2 ALL devenv
${OpenSim_SOURCE_DIR}/Vendors/xerces-c-src2_4_0/Projects/Win32/VC7/xerces-all/xerces-all.sln
/build Release)
i.e. we build the library by essentially making a system call to visual studio
and passing it their supplied .sln.
So basically:
- If you think GetDirectory could be fixed in a way that correctly handles the
UTILITY target type then hopefully that should resolve things and we'll be able
to upgrade to cmake 2.4.
- But if you think one should never try to link to a UTILITY target then we'll
need to come up with a different way to incorporate building this third party
library as part of our regular build and any pointers to doing this nicer would
be appreciated.
So, we should fix the crash of course.
However, if you change the target name to xerces-c_2D_cmake and leave the
target_link_libraries at xerces-c_2D it should work. You can use add_dependency
to make the custom target depend on other targets. I am not sure this was really
working for you with cmake 2.2. It may have been working by luck. Since this
is not really a cmake target linking to it does not make sense. I am assuming
that
the library name is xerces-c_2D?
Yeah, the library name is xerces-c_2D. In any case, your suggested
solution makes sense, so I'll try that out.
Thanks a lot.
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