[LLVMdev] Another Pass Manager Assertion

[John Criswell]

Devang Patel wrote:
> On Dec 18, 2007, at 10:55 AM, John Criswell wrote:
>   
Thanks!.  I didn't realize that functions needed bodies in order to pull 
up their analysis information.

-- John T.
>   
>> Dear All,
>>
>> The attached code (which is a contrived test case) hits the following
>> assertion:
>>
>> test:
>> /home/vadve/criswell/src/llvm22/include/llvm/PassAnalysisSupport.h:
>> 226:
>> AnalysisType& llvm::Pass::getAnalysisID(const llvm::PassInfo*,
>> llvm::Function&) [with AnalysisType = Pass1]: Assertion `ResultPass &&
>> "getAnalysis*() called on an analysis that was not " "'required' by
>> pass!"' failed.
>> Abort
>>
>> Does anyone see anything wrong with my use of the pass manager
>> interface?  As far as I can tell, the code looks correct.
>>     
>
> Your pass manager interface is OK.
>
> You are requesting PassManager to make a Function level analysis pass
> (Pass1) available to Module level transformation pass (BottomPass).
> In real life you could use it to request Dominator information for a
> module level pass. This is supported and it works. The reason it fails
> for your test case is that the function "main" is just a declaration.
> There is no analysis info to generate.
>
> If you add a "main" function body in your module then it should work.
> Or you should check whether F.isDeclaration() is true or not before
> invoking getAnalysis<Pass1>(F);
>
> I agree, the assertion message is not very helpful here.
>
> -
> Devang
>
>
>   
>> -- John T.
>>
>> #include "llvm/Pass.h"
>> #include "llvm/Module.h"
>> #include "llvm/PassManager.h"
>> #include "llvm/Type.h"
>>
>> using namespace llvm;
>>
>> struct Pass1 : public FunctionPass {
>>  public :
>>    static char ID;
>>    Pass1 () : FunctionPass ((intptr_t) &ID) {}
>>    const char *getPassName() const { return "Pass 1"; }
>>    virtual bool runOnFunction(Function &F) {
>>      return false;
>>    }
>>    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
>>      return;
>>    }
>> };
>>
>> struct BottomPass : public ModulePass {
>>  public :
>>    static char ID;
>>    BottomPass () : ModulePass ((intptr_t) &ID) {
>>    }
>>    const char *getPassName() const { return "Bottom Pass"; }
>>    virtual bool runOnModule(Module &M) {
>>      for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
>>        Function &F = *I;
>>        Pass1 &P = getAnalysis<Pass1>(F);
>>      }
>>      return false;
>>    }
>>    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
>>      AU.addRequired<Pass1>();
>>    }
>> };
>>
>> int main(int argc, char **argv) {
>>  Module M("testmodule");
>>  M.getOrInsertFunction ("main", Type::VoidTy, NULL);
>>  PassManager Passes;
>>  Passes.add(new BottomPass());
>>  Passes.run(M);
>>  return 1;
>> }
>>
>> char Pass1::ID = 0;
>> char BottomPass::ID = 0;
>>
>> RegisterPass<Pass1> R1("p1","Pass 1");
>> RegisterPass<BottomPass> R3("b","Bottom Pass");
>>
>> _______________________________________________
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>>     
>
> -
> Devang
>
>
>
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