I have been running into trouble recently trying to symbolicate a crash log of an iOS app. For some reason the UUID of the dSYM was not indexed in Spotlight. After some manual search and a healthy dose of command line incantations, I managed to symbolicate partially the crash log.
At first I thought the dSYM might be incomplete or something like that, but then I realized that the method calls missing were the ones occurring in C++ code: this project is an Objective-C app that calls into C++ libraries (via Objective-C++) which call back to Objective-C code (again, via Objective-C++ code). The calls that I'm missing are, specifically, the ones that happen in C++ land.
So, my question is: is there some way that the symbolication process can resolve the function calls of C++ code? Which special options do I need to set, if any?
One useful program that comes with the apple sdk is atos (address to symbol). Basically, here's what you want to do:
atos -o myExecutable -arch armv7 0x(address here)
It should print out the name of the symbol at that address.
I'm not well versed in Objective-C, but I'd make sure that the C++ code is being compiled with symbols. Particularly, did you make sure to include -rdynamic and/or -g when compiling the C++ code?
try
dwarfdump --lookup=0xYOUR_ADRESS YOUR_DSYM_FILE
you will have to look up each adress manually ( or write a script to do this ) but if the symbols are ok ( your dSym file is bigger than say 20MB) this will do the job .
Related
Working on a C++ based application, it takes user input and generates a C++ function and compile it to create a .so file and links the function to the main application. Currently had to call an external command "g++" to do it. Wonder if it's possible to call some kind of function, say, "compile" which takes as input an code snippet and produces an .so. More precisely, I need a function that has the following syntax:
sizeOfObjBuf = compile(codeBuf, objBuf);
First parameter is a null terminated string containing a code snippet, the second parameter is the output buffer that hold the compiled code and it returns the size of size of compiled code.
The whole idea is to get rid of dependency on an external program (g++) so the application can run on any Linux system (even when it doesn't have g++ installed).
Thanks.
I'm afraid the answer is "no".
You could implement that function by executing G++ (or some other compiler) in a separate process and waiting for it to finish, but that still requires the user to have a compiler installed.
You can't compile C++ code without a C++ compiler.
I am not going to do the research to figure out how it is done, but I believe the LLVM C++ compiler can be used in this way. All of the parts of LLVM are designed to run as a library, in theory.
OK, a tiny bit of research and I found this: http://clang.llvm.org/docs/LibTooling.html
I built Qt from source (dlls) and am trying to build an application that uses the Qt dlls. I don't have a lot of experience with C++ so I'm running into what I'm sure is a very basic issue.
My builds are failing on the includes with errors like so:
Fatal error: QNetworkProxy: No such file or directory
Here is the g++ command I am using (I also used -L to add the correct folder to the lib path, but that also didn't work):
g++ -l..\..\wkqt\bin\QtCore4.dll -l..\..\wkqt\bin\QtNetwork4.dll -l..\..\wkqt\bin\QtWebKit4.dll -I..\include -Ishared -Ipdf -Ilib -Iimage -o ..\bin\wkhtmltopdf.exe pdf\*.cc lib\*.cc image\*.cc shared\*.cc
I tried in Visual Studio as well (assuming it wouldn't build, but I wanted to see if I could at least include the Qt dlls from there properly) and I am getting the same errors. Am I doing something wrong with the way I am compiling with g++? If I am linking with the Dlls properly then what is the proper way to use Qt functions from my code?
To clarify, I am not looking for how to properly use Qt. My question is: what is the proper way to use functions defined in any Dll from native C++ code? I apologize if this is a very basic question, but I'm unable to find a clear answer on Google and I don't have any experience with C++ and including third party libraries for use from C++ code.
DLLs can be used by dynamicly loading them and calling their used functions.
to call the exposed functions first define their syntax in the begining
suppose function is syntax is
BOOL MyFunction(int a,char* pszString)
then define syntax
#typedef BOOL (WINAPI *PMYFUNCTION)(int a,char* pszString)
then make object
PMYFUNCTION pfnMyFunction;
and get valid pointer by calling GetProcaddress after loadlibrarycall
HMODULE hlib= Loadlibrary("c:\\Mylib.dll");
if(hlib)
{ pfnMyFunction = (PMYFUNCTION)Getprocaddress(hlib,"MyFunction"); }
Hope this helps...
I want to use LEAP Motion in D.
Therefore It doesn't have C library and It has only C++ library.
I tried SWIG 2.0.9 below command.
swig -c++ -d -d2 leap.i
This command output Leap.d, Leap_im.d, Leap_wrap.cxx, Leap_wrap.h.
However, I don't know how to use to wrapper in D and I can't find how to use the wrapper.
Link error displays to use it intact.
How use these wrapper in D2?
And can I use without Leap.cpp (source of Leap.dll)?
Update:
Thanks two answers. and sorry for reply late because of busy.
Say first conclusion I could build Leap sample code on Win64 by following the steps below.
Output wrappers by above command.
Create x64 DLL with VC2010 from Leap_wrap.cxx, Leap_wrap.h, and import Leap.lib(x64).
Compile Leap.d and Leap_im.d with dmd -c.
Build LeapTest.d with Leap.obj and Leap_im.obj
all command is below.
swig -c++ -d -d2 leap.i
dmd -c Leap.d Leap_im.d -m64
dmd LeapTest.d Leap.obj Leap_im.obj -m64
execute LeapTest.exe (require x64 Leap.dll and Leap_wrap.dll)
I could run Leap Program.
But program crach onFrame event callback.
I'll try again on x86 and investigate the causes.
Few helpful links (some information may be outdated):
http://klickverbot.at/blog/2010/11/announcing-d-support-in-swig/
http://www.swig.org/Doc2.0/D.html
http://www.swig.org/tutorial.html
I have never used SWIG personally but my guess based on general knowledge about SWIG:
Leap_wrap.cxx is C++ source file that wraps calls to C++ functions from target library in extern(C) calls
Leap_wrap.h is header file with all extern(C) wrappers listed
Leap_im.d is D module based on Leap_wrap.h with same extern(C) function listed
Leap.d is D module that uses Leap_im.d as an implementation and reproduces API similar to original C++ one.
So in your D code you want to import Leap.d module. Than compile Leap_wrap.cxx to an object file with your C++ compiler and provide D object files, Leap_wrap.o and target library at linking stage. That should do the trick.
P.S. Leap.cpp source should not be needed. All stuff links directly from Leap_wrap.cxx to target library binary.
Go to IRC, either FreeNode, or OFTC, channel #D. In order to help you, we have to see what is in those files. My first guess is that you have to compile both D files, and the C++ file into object files, and link them together. I suppose SWIG is going to flatten the C++ API into bunch of C functions, and that is probably what Leap_wrap.cxx does.
If the LEAP API is not complex (ie. just bunch of simple C++ classes), it may be possible to directly interface with it. Read more about it here: http://dlang.org/cpp_interface.html .
I'm working on a bare-metal cortex-M3 in C++ for fun and profit. I use the STL library as I needed some containers. I thought that by simply providing my allocator it wouldn't add much code to the final binary, since you get only what you use.
I actually didn't even expect any linking process at all with the STL
(giving my allocator), as I thought it was all template code.
I am compiling with -fno-exception by the way.
Unfortunately, about 600KB or more are added to my binary. I looked up what symbols are included in the final binary with nm and it seemed a joke to me. The list is so long I won't try and past it. Although there are some weak symbols.
I also looked in the .map file generated by the linker and I even found the scanf symbols
.text
0x000158bc 0x30 /CodeSourcery/Sourcery_CodeBench_Lite_for_ARM_GNU_Linux/bin/../arm-none-linux-gnueabi/libc/usr/lib/libc.a(sscanf.o)
0x000158bc __sscanf
0x000158bc sscanf
0x000158bc _IO_sscanf
And:
$ arm-none-linux-gnueabi-nm binary | grep scanf
000158bc T _IO_sscanf
0003e5f4 T _IO_vfscanf
0003e5f4 T _IO_vfscanf_internal
000164a8 T _IO_vsscanf
00046814 T ___vfscanf
000158bc T __sscanf
00046814 T __vfscanf
000164a8 W __vsscanf
000158bc T sscanf
00046814 W vfscanf
000164a8 W vsscanf
How can I debug this? For first I wanted to understand what exactly GCC is using for linking (I'm linking through GCC). I know that if symbol is found in a text segment, the
whole segment is used, but still that's too much.
Any suggestion on how to tackle this would really be appreciated.
Thanks
Using GCC's -v and -Wl,-v options will show you the linker commands (and version info of the linker) being used.
Which version of GCC are you using? I made some changes for GCC 4.6 (see PR 44647 and PR 43863) to reduce code size to help embedded systems. There's still an outstanding enhancement request (PR 43852) to allow disabling the inclusion of the IO symbols you're seeing - some of them come from the verbose terminate handler, which prints a message when the process is terminated with an active exception. If you're not using execptions then some of that code is useless to you.
The problem is not about the STL, it is about the Standard library.
The STL itself is pure (in a way), but the Standard Library also includes all those streams packages and it seems that you also managed to pull in the libc as well...
The problem is that the Standard Library has never been meant to be picked apart, so there might not have been much concern into re-using stuff from the C Standard Library...
You should first try to identify which files are pulled in when you compile (using strace for example), this way you can verify that you only ever use header-only files.
Then you can try and remove the linking that occurs. There are options to pass to gcc to precise that you would like a standard library-free build, something like --nostdlib for example, however I am not well versed enough in those to instruct you exactly here.
I'm trying to build a simple unit test executable, using cpputest. I've built the cpputest framework into a static library, and am now trying to link that into an executable. However, I'm tied into a fairly complicated Makefile setup, because of the related code.
This is my command line:
/usr/bin/qcc -V4.2.4,gcc_ntoarmle_acpp-ne -lang-c++ -O2 -g -g -o Application/UnitTests/Tests/symbols/UnitTestExe -Wl,--start-group Application/UnitTests/Tests/../.objs/main.o Application/UnitTests/lib/libcpputest.a -Wl,--end-group -lm
I'm getting many errors like the following:
Application/UnitTests/lib/libcpputest.a(CommandLineTestRunner.o): In function `CommandLineTestRunner::parseArguments(TestPlugin*)':
Application/UnitTests/cpputest/src/CppUTest/.objs/../CommandLineTestRunner.cpp:114: undefined reference to `operator new(unsigned int, char const*, int)'
I can't figure out what's causing this. Don't I get operator new for free with C++?
You probably need to link with the C++ support runtime library. This happens automatically when you invoke g++. On Linux, this is achieved by adding the -lstdc++ flag to the linker. You have to figure out how to do the same on your platform.
Maybe you're calling gcc, the C compiler instead of g++, which is the C++ compiler.
There's very little information in your question to work from, but it looks like some code uses some form of placement new, and while that special operator new is declared (the compiler finds it and compiles the code using it), the linker can't find its definition.
(Since this old answer of mine seems to still get attention: See here for an extensive discussion on declaration vs. definition.)
You need to rebuild your code from scratch, including the library. I got this error because I inadvertently copied object files compiled on another machine (with the rest of the source) to my machine. Most likely this disturbs the linking step since there are now two types of object files, native (for modified source files) and non-native (all others). I am guessing here, but the operator 'new' means slightly different things on different architectures and that's why you are getting this error.
p.s. I know this is way too late for a useful answer but I'm still posting this for the record.
For QNX 6.5.0 I have specified flag -lang-c++ for qcc (gcc) to avoid the error.
Like the original post, in my case this error happened while trying to link a software using CppUTest framework.
In my case, the source of the problem seems to be related to the fact I disabled the MEMORY_LEAK_DETECTION compile option of CppUTest. I enabled it again, which solved the problem.
Sometimes adding -lstdc++ is not enough. You should add it to the right place. For example I had list like this, not working:
target_link_libraries(cfr2 pthread m stdc++ "${CMAKE_SOURCE_DIR}/compressor/libcompressor.a" )
But this one works fine:
target_link_libraries(cfr2 pthread m "${CMAKE_SOURCE_DIR}/compressor/libcompressor.a" stdc++)
It'd be great if someone explained it in the comment section.