Hi,
Thanks Chris. Following your suggestion, I wrote the code to hide the visible string. Thanks again. Finially, I just realized my LLVM still is 1.2, not 1.3. Now I update it to 1.3.
> > 5. Insert the for loop that translates the string when main runs.
> >
> > For #5, write the for loop you want, compile it with llvmgcc, then figure
> > out how to generate it at compile time. Alternatively, you could put the
> > 'decryption' routine in a library and just insert a call to the library.
For decode part. I can write a pass to decode the hide-string bytecode( after hide string pass, I create a globalvariable to store the Key for decode routine. And on the decode pass, I use this Key to recover the orignal bytecode.
It seems not good way to decode. The better way should be to embed the decode routine into the bytecode in the entry of main. So the question is how to do it?
What I can do is that,
I can create call instruction and insert it into entry BB of main. And this call function is able to call the a function of the external library which I could create as I want( just using C style). And I can write decode pass, but I don't know how to build a library as the way you mentioned. Actually, I was thinking the pass I wrote is a dynamic library as libdecode.so. So could I use it? if not, how to build the library you mentioned? I thought the library you mentioned should be similar with the pass. However, I have no idea how combine them?
Thanks
Qiuyu
Hi,
Thanks Chris. Following your suggestion, I wrote the code to hide the
visible string. Thanks again. Finially, I just realized my LLVM still is
1.2, not 1.3. Now I update it to 1.3.
ok.
> > > 5. Insert the for loop that translates the string when main runs.
> > >
> > > For #5, write the for loop you want, compile it with llvmgcc, then figure
> > > out how to generate it at compile time. Alternatively, you could put the
> > > 'decryption' routine in a library and just insert a call to the library.
For decode part. I can write a pass to decode the hide-string bytecode(
after hide string pass, I create a globalvariable to store the Key for
decode routine. And on the decode pass, I use this Key to recover the
orignal bytecode.
Sure.
It seems not good way to decode. The better way should be to embed the
decode routine into the bytecode in the entry of main. So the question
is how to do it?
That's fine, take a look at how the profiling instrumentation code works
in lib/Transforms/Instrumentation. That should give you examples of how
to insert function calls. grep for 'new CallInst'.
What I can do is that,
I can create call instruction and insert it into entry BB of main.
And this call function is able to call the a function of the external
library which I could create as I want( just using C style). And I can
write decode pass, but I don't know how to build a library as the way
you mentioned. Actually, I was thinking the pass I wrote is a dynamic
library as libdecode.so. So could I use it? if not, how to build the
library you mentioned? I thought the library you mentioned should be
similar with the pass. However, I have no idea how combine them?
Yes, this is no problem. The profiling instrumentation inserts function
calls which get resolved to the llvm/runtime/libprofile library. Please
look at how that works and you can pattern off of that.
-Chris