Hi,
For libstdc++ and libsupc++, I can their source code in l4/pkg/libstdc++-v3/contrib, but I couldn't fine the source code for libgcc. Where is the source code for libgcc?
Thanks a lot. Yuxin
On Sat, Jun 27, 2015 at 5:30 PM, Adam Lackorzynski adam@os.inf.tu-dresden.de wrote:
On Fri Jun 26, 2015 at 19:01:21 -0400, Yuxin Ren wrote:
Hi,
I just want to make sure that you do not misunderstand my questions. All my questions are related the user level, that is l4re, not the kernel.
Ok, I see, when you mention Fiasco I always think of the kernel. So for userland:
Regarding new/delete: No changes Regarding modifying libstdc++, libsupc++ and libgcc: No changes, except libgcc on ARM where Linux specific atomic ops are exchanged with L4 ones. Regarding locks: We build against pthreads.
One more question, does Fiasco provide its owner gthred wrappers to the gcc?
No.
Adam
On Fri, Jun 26, 2015 at 6:34 PM, Adam Lackorzynski adam@os.inf.tu-dresden.de wrote:
On Fri Jun 26, 2015 at 22:44:07 +0800, Yuxin Ren wrote:
You said Fiasco implements its own new/delete operator, could you show me where the code for those is?
There are several placement new's, for example in thread.cpp and task.cpp. Just look for "operator new" in those files.
In addition, does Fiasco modify the code of libstdc++, libsupc++ and libgcc?
Fiasco, the kernel, does not use libstdc++ nor libsupc++, and it also does not modify libgcc as far as it is using it.
I think inside those libraries, they may use locks. And we need to use the Fiasco's lock implementation, not Linux's.
Generally, libstdc++ does not depend on Linux, it can for example also use pthreads internally.
Another confusion comes from the local static object. In order to guarantee its constructor only run once, the compiler will insert lock around the constructor. but does the gcc know which lock implementation to use?
This is disabled by using -fno-threadsafe-statics.
Adam
Adam adam@os.inf.tu-dresden.de Lackorzynski http://os.inf.tu-dresden.de/~adam/
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