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[Baozeng <sploving1 AT gmail.com>]

2012/6/14 John Criswell 
<criswell AT illinois.edu>:
> On 6/13/12 8:37 AM, Baozeng wrote:
>>
>> Hello,
>> I use current BBC implementation to test an example (buffer.c):
>>
>> #include<stdio.h>
>> #include<stdlib.h>
>>
>> int main (int argc, char ** argv) {
>>   char array[17];
>>   return array[17];
>> }
>>
>> $ clang -g -fmemsafety -bbc buffer.c -o mytest
>> -L/home/sploving/llvm/projects/safecode/Debug/lib
>> $ ./mytest
>>
>> It output this:
>> 0xbfd00b9b, 0xbfd00b80, 17 Not aligned
>>
>> This related code is in the function __internal_register in
>> BaggyBoundsCheck.cpp:
>>
>> if(Source1 != Source) {
>>     printf("%p, %p, %u Not aligned\n", (void*)Source, (void*)Source1,
>> NumBytes);
>>     assert(0&&  "Memory objects not aligned");
>>   }
>
>
> I think the problem is that the stack object being registered isn't aligned
> on a power-of-two boundary like it should be.
>
yep.
I debugged and found that the function adjustAlloca is not called.
I inserted some printf statement in the following function:

void
InsertBaggyBoundsChecks::adjustAllocasFor (Function * F) {
  //
  // If there is no such function, do nothing.
  //
  if (!F) return;
  printf("test1\n");     // It output!
  //
  // Scan through all uses of the function and process any allocas used by it.
  //
  for (Value::use_iterator FU = F->use_begin(); FU != F->use_end(); ++FU) {
    printf("test2\n");   // It does not ouput!
    if (CallInst * CI = dyn_cast<CallInst>(*FU)) {
printf("test3\n");   // It does not ouput!
      Value * Ptr = CI->getArgOperand(2)->stripPointerCasts();
      if (AllocaInst * AI = dyn_cast<AllocaInst>(Ptr)){
        adjustAlloca (AI);
   printf("test4\n");    // It does not ouput!
      }
    }
  }

  return;
}

Only test1 was printed out. So the statements in the for loop are not
executed. why?
> Does the transform that does that work yet?  If so, then maybe something
> else is causing the problem (like the poolargvregister() function).
>
> -- John T.
>
>>
>> Source1 should be equal with Source if Source satisfy some conditions.
>> What conditions should Source satisfy? Maybe this is related to pool
>> handler? How to fix this?
>>
>>
>>
>>
>



-- 
     Best Regards,
                                                                 Baozeng Ding
                                                                 
OSTG,NFS,ISCAS