Hi Heming,
If you run the example with just the return and without local vars, you should
check in the assembly.ll to see if the call is not removed.
Local variables are removed on function return, check ExecutionState.cpp:112
You can maybe check the # of bytes removed, there could be a bug.
Cristi
On Apr 1, 2010, at 5:33 AM, Heming Cui wrote:
> Dear Daniel and Cristian,
> One more thing is, if I do not declare any local var at foo() and just
> return (as below), the memory usage is only about 1%.
> void foo() {
> return;
> }
>
>
> 2010/3/31 Heming Cui <heming at cs.columbia.edu>
> Dear Daniel and Cristian,
> I am Heming Cui, Prof. Junfeng Yang's student. May I ask you a question,
> please? Recently I was running klee with some long running programs and found
> a question about the memory usage of local variable of functions in klee.
> Please refer to the source code below (and also in the attachment). Foo()
> dedclares a function local var, and the main function calls fool() again and
> again. If I compile this code with llvm-gcc and run the bit code with klee,
> the memory usage increases to more than 90% as soon as the program starts and
> never drops. The memory in my machine is 2GB. If I compile this code with gcc
> and run it natively, and the memory usage is only 0.1% and never increases.
> If I change "int a[100000];" to be "int a;", the memory usage would
> increase to more than 90% after about 10 seconds of start, and never drops.
> It seems to me that we might need to unbind local vars in klee memory
> address space after a function exits? I am a little confused of this part,
> since if my program runs for a long time, this problem would happen and
> affect the speed.
>
> Memory usage of klee is 93.3%:
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
>
> 3099 heming 20 0 1773m 469m 4 D 1.7 93.3 0:04.18 klee
>
>
> Source code (also attached):
>
> #include <stdio.h>
> void foo() {
> int a[100000];
> return;
> }
>
> int main(int argc, char * argv[]) {
> while (1) {
> foo();
> }
>
> return 0;
> }
>
> --
> Regards,
> Heming Cui
>
>
>
>
> --
> Regards,
> Heming Cui
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