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Why does a 2-stage command-line build with clang not generate a dSYM directory?
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My compile command is in macOS Sierra is
clang -std=c11 -g -Wall -Werror -fsanitize=address -file.c -o file
after it compiles, it also generates an extra file.dSYM file which included all debug symbols. However, when I use WSL or other *nix system it will not generate such file, debug symbols were embedded into executable binaries.
So I just wondering is there a way to do the same in macOS with clang.
When you compile a program in one pass, clang actually runs dsymutil for you, which is responsible for creating the .dSYM file. Thus, the solution to your problem is to compile and link separately, in which case clang won't automatically call dsymutil.
Check this SO question for more details!
Related
I'm using mingw-w64 (gcc 7.3.0) and when I compile any C++ program using the following command:
g++ file.cpp -fsanitize=undefined
I get the following error:
...mingw32/bin/ld.exe: cannot find -lubsan
I'm able to successfully compile and run my programs if I remove the -fsanitize=undefined flag, though. After some research I found out that this means the library ubsan (Undefined Behavior Sanitizer) is missing, but I couldn't find anything about the library. How do I fix this?
This is well known issue with mingw see for instance this msys github issue. No proper solution known but there are several WAs.
Install WSL, ubuntu over WSL and you will have ubsan inside it
Build GCC under Windows from source enabling sanitizers build. They are present in GCC sources they are just not here in mingw.
Use -fsanitize=undefined -fsanitize-undefined-trap-on-error to just not use libubsan rich logging capabilities but get it trap on undefined instruction.
Hope one of this helps.
I working on trying to compile a code written in C++ and Root on my Mac. The code is from a colleague who works on a Linux laptop. In addition to the different OS's, I have both a different version of gcc and Root than her and I am not sure which difference is causing the code not to compile on my machine.
She has g++ 4.8 and root 5.(something). I have gcc 5.3.0 and root 6.06/02.
She has given to me the a line of code she uses to get her machine to compile the code
gcc -Wall -o executable_name code_name.cc `root-config --cflags --glibs`
But when I write on my machine, Terminal gives me the error
gcc: error: unrecognized command line option ‘-stdlib=libc++’
gcc: error: unrecognized command line option ‘-stdlib=libc++’
I need help generating the correct line to get gcc to compile the code.
The problem here is two-fold: You're on OSX and you are using GCC.
The problem with this is that root-config assumes that since you're on OSX you will be using the OSX-standard Clang compiler which have the -stdlib flag. Since you're not using Clang, but GCC (which doesn't have this flag) you get an error.
You have two possible solutions: Use clang++ instead of g++ to compile and build (requires you to install the compiler if it's not installed already, it comes with Xcode), or to modify the root-config script so it doesn't add -stdlib=libc++. There might be environment variables or flags that the root-config script checks that alter the behavior, but I don't know anything about the script, you have to check it for that.
I have a simple project I want to debug want to produce dSYM folder with debugging symbols.
Running:
clang++ -std=c++14 -stdlib=libc++ -g -o Lazy Lazy.cpp
Creates Lazy.dSYM as I expect.
However:
clang++ -std=c++14 -stdlib=libc++ -g -c Lazy.cpp
clang++ -stdlib=libc++ -g -o Lazy Lazy.o
Does not create Lazy.dSYM (It seems that the symbols are embedded in the binary).
Sadly the 2-step build is what my modified makefile does. How can I generate Lazy.dSYM from a 2-stage compile-and-link build?
I don't need a dSYM directory, just debugging symbols, but would like to understand when and why it is created.
The creation of the .dSYM bundle is done by a tool called dsymutil. When Apple added support for DWARF debugging information, they decided to separate "executable linking" from "debug information linking". As such, the debug information linking is not done by the normal linker, it's done by dsymutil.
As a convenience, when you build a program all in one step, the compiler invokes dsymutil on your behalf. That's because it knows it has all of the inputs. If you add the -v (a.k.a. --verbose) option to the compile command, you will see the invocation of dsymutil as the last step it does.
In other cases, though, it doesn't do that. It leaves the debug information linking step for the user to do manually. You can do it by simply issuing the command:
dsymutil <your_program>
Here's an article by an Apple engineer who helped design and implement Apple's support for DWARF explaining their thinking. He also answered a question here on Stack Overflow about this stuff.
I am compiling a c++14 project on MacOsX10.10 using cmake, clang++, boost and openCV (static linkage - compilation flags: -Wall -std=c++14 -O3). How can I make sure the program runs out-of-the-box in older MacOsX versions? (and in other mac computers as well?) I've tested the binary on an older macbook running os X 10.7 and it failed. With xcode it's possible to build a program against some particular SDK, can I do something similar from the command line?
P.S. This is a more general question, but the source code for this particular project can be found here: https://github.com/MarinosK/oiko-nomic-threads
You need to make sure that all dependencies are linked statically into your executable. So this not only includes the .a (static libraries or object archives) but also the C++ (and possibly C) standard libraries.
For example:
clang --std=c++14 -stdlib=libstdc++ main.cpp -o main thirdparty.a -static -lstdc++
I've recently built libc++ from scratch as my prject needs some features that are not yet implemnted in libstdc++.
I try to compile the hello world program located in src/main.cpp with line
clang -Wall -stdlib=libc++ -std=c++11 -c src/main.cpp -obuild/main.o
and the build suceeds
Then I link it with
clang -lc++ build/main.o -o qasix
and the linking suceeds too.
But when I run the program with
./qasix
I get the following error:
./qasix: symbol lookup error: /usr/local/lib/libc++.so.1: undefined symbol: _ZTVN10__cxxabiv120__si_class_type_infoE
I would like to know why this is occurring and also how to fix it.
I am on Xubuntu 13.10 if that's of any help.
PS: This problem popped up yesterday. Earlier other libc++ programs would compile fine.
This started when I did a debug build of a program with the -g flag and it compiled and ran fine, but all later programs complained about this symbol lookup failure. Please help.
it appears that you need the support library "libc++abi". It provides things like low-level exception support, type_info support, etc.
For Ubuntu (as opposed to Xubuntu), it appears that you can get it here: http://www.ubuntuupdates.org/package/core/saucy/universe/base/libc++abi-dev