[LLVMdev] Another Pass Manager Assertion

[Devang Patel]

On Dec 18, 2007, at 10:55 AM, John Criswell wrote:

> 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