Svadev mailing list

[John Criswell <criswell AT illinois.edu>]

On 5/24/12 11:04 PM, Daniel Huang wrote:

Ahh, forgot to reinstall the libLTO stuff, thanks. After reinstalling, I've tried running these 3 command line combinations ...

1) clang -flto -fmemsafety test.c -S -o test.ll

Compiles, but no pools.

2) clang -flto -fmemsafety -emit-llvm test.c -S -o test.ll

clang: warning: argument unused during compilation: '-flto'

Compiles, but no pools.

The above two commands do not invoke the linker which is why you don't get any pool allocation.

3) clang -flto -fmemsafety test.c -o test.o

Pool allocating 6 global nodes!

[main] 5 nodes pool allocatable

So it looks like the 3rd one works, but its not in a human readable form ... Is there any way to get safecode to output the pools in a human-readable form?

I think the only way to do that is to add a BitcodeWriter pass after the pool allocation pass to write the output to a file.  I can add that first thing tomorrow morning.

-- John T.

Thanks!

On Thu, May 24, 2012 at 7:04 PM, John Criswell <criswell AT illinois.edu> wrote:

On 5/24/12 5:56 PM, Daniel Huang wrote:

I added -DPOOLALLOC but still haven't been able to get any programs to emit poolalloc or poolinit instructions. Perhaps I misunderstood you, but I modified safecode's Makefile.common SC_FLAGS with -DPOOLALLOC.

Did you recompile the code?  Did you reinstall the SAFECode libLTO after the recompile?  Are you giving clang the proper command-line arguments to make it use libLTO?

Poolalloc is performed by libLTO.  If you aren't using libLTO (or if you've installed it incorrectly), then the automatic pool allocation transform won't be run.  You need to use the SAFECode libLTO; directions can be found in the SAFECode Install Guide and User's Guide on the SAFECode web page.

Also, do you have an example program which will cause the tool to emit these instructions?

With the SAFECode heuristic, pretty much any code with memory allocations will generate pool functions.  You might want to try using code examples from the SAFECode or Poolalloc papers.

I'm really curious to see where pools are created and destroyed. For example, can they be created in the middle of the function, or are they only ever created at the beginning of a function and destroyed at the end.

I believe dynamically allocated pools are always created a function entry and destroyed at function exit.

-- John T.