llvm dev - Jun 2010 - [LLVMdev] Why google-perftools fails on the JITted code?

I am trying to run some code allocating a lot of memory and not 
releasing it in JIT under google-perftools. Just one function 'main' 
calling 'malloc'.
google-perftools fails to correctly read stack when malloc is called 
from inside the JITted code, and as a result perftools report is wrong: 
address of 'main' procedure appears shifted 0x3946e1d0->0x3946e1ed
and
is not aligned. And calling it procedure (runFunction) is skipped, but 
higher in stack methods are shown correctly.

This causes me to ask this question: when the code is run in JIT, are 
the stack frames (and prologs) different from when the code results from 
compiler? Is it still possible to read this stack correctly using the 
same procedure for both JITted and regular code?

Yuri

Now I see that JITted code doesn't have standard prolog, on x86 each 
procedure instead begins with 'sub    $0x4,%esp'.

Is there an option to make JIT generate regular prologs?

Yuri

On Jun 18, 2010, at 3:29 AM, Yuri wrote:
> Now I see that JITted code doesn't have standard prolog, on x86 each 
> procedure instead begins with 'sub    $0x4,%esp'.
> 
> Is there an option to make JIT generate regular prologs?
Try turning off frame pointer elimination.  On the llc command line, this is
-disable-fp-elim

-Chris

> 
> Yuri
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