Hi all,
I have a code with three passes (one loop pass and two module passes)
and my own pass manager. If I schedule the loop pass between the others,
my code segfaults. Is there any explanation why loop passes cannot be
scheduled between two module passes? Perhaps I misunderstood the
behaviour of pass managers.
I paste here my "usage" information:
int main(...){
Module m = ... //Read module
PassManager pm;
pm.add(new ModPass1);
pm.add(new LoopPass);
pm.add(new ModPass2);
pm.run(m);
}
class ModPass1 : public ModulePass{
virtual void getAnalysisUsage(AnalysisUsage&AU) const{
AU.setPreservesAll();
}
};
class LoopPass : public LoopPass{
virtual void getAnalysisUsage(AnalysisUsage&AU) const{
AU.setRequires<ModPass1>();
AU.setPreservesAll();
}
};
class ModPass2 : public ModulePass{
virtual void getAnalysisUsage(AnalysisUsage&AU) const{
AU.setRequires<LoopPass>();
AU.setPreservesAll();
}
};
If I remove any of the passes (updating the usage information), it's OK.
If I transform the loop pass into a module pass, it also works.
Thanks ahead,
--
Pablo Barrio
Dpt. Electrical Engineering - Technical University of Madrid
Office C-203
Avda. Complutense s/n, 28040 Madrid
Tel. (+34) 915495700 ext. 4234
@: pbarrio at die.upm.es
Hi Pablo,> I have a code with three passes (one loop pass and two module passes) > and my own pass manager. If I schedule the loop pass between the others, > my code segfaults.when developing with LLVM you should configure with --enable-assertions. That way you should get an assert failure with a helpful message rather than a crash. Is there any explanation why loop passes cannot be> scheduled between two module passes? Perhaps I misunderstood the > behaviour of pass managers. > > I paste here my "usage" information: > > int main(...){ > > Module m = ... //Read module > PassManager pm; > > pm.add(new ModPass1); > pm.add(new LoopPass); > pm.add(new ModPass2); > pm.run(m); > > } > > class ModPass1 : public ModulePass{ > > virtual void getAnalysisUsage(AnalysisUsage&AU) const{ > AU.setPreservesAll(); > } > }; > > class LoopPass : public LoopPass{ > > virtual void getAnalysisUsage(AnalysisUsage&AU) const{ > AU.setRequires<ModPass1>();I'm pretty sure a LoopPass cannot require a ModulePass. Ciao, Duncan.> AU.setPreservesAll(); > } > }; > > class ModPass2 : public ModulePass{ > > virtual void getAnalysisUsage(AnalysisUsage&AU) const{ > > AU.setRequires<LoopPass>(); > AU.setPreservesAll(); > } > }; > > > If I remove any of the passes (updating the usage information), it's OK. > If I transform the loop pass into a module pass, it also works. > > Thanks ahead, >
Hi Duncan,> Hi Pablo, > >> I have a code with three passes (one loop pass and two module passes) >> and my own pass manager. If I schedule the loop pass between the others, >> my code segfaults. > when developing with LLVM you should configure with --enable-assertions. > That way you should get an assert failure with a helpful message rather > than a crash.Sorry, I forgot to add the assertion failure: PassManager.cpp:540: void llvm::PMTopLevelManager::setLastUser(const llvm::SmallVectorImpl<llvm::Pass*>&, llvm::Pass*): Assertion `AnalysisPass && "Expected analysis pass to exist."' failed.> class ModPass1 : public ModulePass{ > > virtual void getAnalysisUsage(AnalysisUsage&AU) const{ > AU.setPreservesAll(); > } > }; > > class LoopPass : public LoopPass{ > > virtual void getAnalysisUsage(AnalysisUsage&AU) const{ > AU.setRequires<ModPass1>(); > I'm pretty sure a LoopPass cannot require a ModulePass.Is it possible to overcome this limitation? I need to access and modify the loops in a function. Is it possible to do that from the function itself, or is the loop pass the only way to get Loop objects? If I can do it from a Module (or another) pass, I don't mind. Loop passes just sound to me like the most straightforward way. Thanks for your time, -- Pablo Barrio Dpt. Electrical Engineering - Technical University of Madrid Office C-203 Avda. Complutense s/n, 28040 Madrid Tel. (+34) 915495700 ext. 4234 @: pbarrio at die.upm.es