llvm dev - Jul 2009 - [LLVMdev] Pass Scheduling Information without using opt

Daniel Dunbar wrote:
> Ah, in this case llvm_shutdown isn't what you are looking for. I've
> never looked at the Statistic implementation so I can't be any help
> here, but if you poke around starting with "llvm/ADT/Statistic.h"
you
> may find a way to do what you want.
I looked into that already, but Statistic.h only gives me the
possibility to implement tracking and printing of my own statistics.
What I want should be located somewhere in the PassManagers, but I do
not find anything helpful. DbgInfoPass only prints out the cfg, same for
CFGPrinterPass (which I can do better by using viewCFG() anyways).
I also found PMDataManager::dumpPassInfo(), but could not get any
information out of it - however, I am also not sure how to use it
correctly and I guess it will probably also not provide statistics about
the PassManager run as a whole.

Here is some example code that describes what I am doing:

MyPass : ModulePass {

bool runOnModule(mod) {

for some Functions f in mod {
(do some stuff)

ExistingModuleProvider mp(mod);
FunctionPassManager* fpm new FunctionPassManager(&mp);

fpm->add(createLowerSwitchesPass());
fpm->add(createBreakCriticalEdgesPass());
fpm->add(createLoopSimplifyPass());

fpm2->run(*f);

mp.releaseModule();

(do more stuff)
}

}

}


Now what I want to have is some runtime-output of the pass manager that
tells me what passes were run in what order, give me timing information
if possible etc.

I hope my explanation is better this time :).

Cheers,
Ralf

On Mon, Jul 27, 2009 at 1:43 AM, Ralf Karrenberg<Chareos at gmx.de>
wrote:
> Here is some example code that describes what I am doing:
>
> MyPass : ModulePass {
>
> bool runOnModule(mod) {
>
> for some Functions f in mod {
> (do some stuff)
>
> ExistingModuleProvider mp(mod);
> FunctionPassManager* fpm > new FunctionPassManager(&mp);
I think creating a new Function Pass Manager inside a module pass is
not ideal, however...
>
> fpm->add(createLowerSwitchesPass());
> fpm->add(createBreakCriticalEdgesPass());
> fpm->add(createLoopSimplifyPass());
>
> fpm2->run(*f);
>
> mp.releaseModule();
>
> (do more stuff)
> }
>
> }
>
> }
>
>
> Now what I want to have is some runtime-output of the pass manager that
> tells me what passes were run in what order, give me timing information
> if possible etc.
You can set global PassDebugging enum. The pass manager will print
useful info while it is running. See initial part of
VMCore/PassManager.cpp for more information on PassDebugging enum.

-
Devang

Hey Devang,

thanks for your answer! :)

Devang Patel schrieb:
> I think creating a new Function Pass Manager inside a module pass is
> not ideal, however...
>   
Currently, I don't see any other way to do it - I need to generate new 
functions and thus need to have access to the whole module. Plus, the 
pass involves some overhead that only has to be computed once per module 
instead of once per function.
However, the module pass itself is not really used: the class is 
instantiated directly using a wrapper...
If you have any general suggestions on how you would try to handle this, 
please tell me. :)
> You can set global PassDebugging enum. The pass manager will print
> useful info while it is running. See initial part of
> VMCore/PassManager.cpp for more information on PassDebugging enum.
I tried that, but I don't understand how this is working and how/what I 
should set :(.

Regards,
Ralf