[ Error while running my pass with opt]

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1

Hi,

you need something like this in your pass:

void YourPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addRequired<DominatorTree>();
}

because you need to specify which analysis you are using.

Tobi

2

But this is already present in my pass.
And I am not able to understand the cause for the error:

opt: /home/ambika/llvm_3/llvm-2.6/include/llvm/PassAnalysisSupport.h:203: AnalysisType& llvm::Pass::getAnalysisID(const llvm::PassInfo*) const [with AnalysisType = llvm::DominatorTree]: Assertion `ResultPass && "getAnalysis*() called on an analysis that was not " "'required' by pass!"' failed.

What can possibly cause this. Any ideas will also help.

Tobias Grosser wrote:

3

Try setting breakpoint in your getAnalysisUsage() and see if it's
actually called. Maybe there's a subtle difference in signature.
Failing that, try breaking on assertion failure and examining it more closely.

4

ambika wrote:

But this is already present in my pass.
And I am not able to understand the cause for the error:
  
Can you send a copy of your getAnalysisUsage() method for your pass? There are some funny errors that can occur when you do things that the PassManager cannot handle.

For example, if you're requiring a transform pass, that can cause strange assertions from the PassManager. Requiring a BasicBlock pass from a FunctionPass might also hit assertions within PassManager (I think).

If you post your getAnalysisUsage() method, I can take a quick look to see if you're doing something that I know is unsupported by PassManager.

-- John T.

5

Here is getAnalysisUsage() i am using,

   void getAnalysisUsage(AnalysisUsage &AU) const {
      AU.setPreservesAll();
      AU.addRequired<DominatorTree>();
    }

and then I use it as,

bool ptrTest::runOnModule(Module &M) {

  DominatorTree &DT = getAnalysis<DominatorTree>();
  ......

}

John Criswell wrote:

6

ambika wrote:

Here is getAnalysisUsage() i am using,

   void getAnalysisUsage(AnalysisUsage &AU) const {
      AU.setPreservesAll();
      AU.addRequired<DominatorTree>();
    }

and then I use it as,

bool ptrTest::runOnModule(Module &M) {

  DominatorTree &DT = getAnalysis<DominatorTree>();
  ......

}
  
Weird. There is nothing unusual about your getAnalysisUsage() method at all.

I assume ptrTest is either a ModulePass or FunctionPass, correct?

A few other questions:

1) Is ptrTest part of an analysis group?

2) Does ptrTest has a static ID member whose address is passed into its constructor as a default parameter? The code should look something like this:

public :
    static char ID;
    ptrTest () : FunctionPass ((intptr_t) &ID) { }

-- John T.

7

John Criswell wrote:

ambika wrote:

Here is getAnalysisUsage() i am using,

    void getAnalysisUsage(AnalysisUsage&AU) const {
       AU.setPreservesAll();
       AU.addRequired<DominatorTree>();
     }

and then I use it as,

bool ptrTest::runOnModule(Module&M) {

   DominatorTree&DT = getAnalysis<DominatorTree>();

DominatorTree is per-function. In a ModulePass you need to pass a Function in order for it to know which function you want the DominatorTree for.

Nick

8

Yaah Dominator tree is generated per function. It worked out when I used it as

   AU.addRequired<DominatorTree>(F);

Thanks to all for helping me.

Nick Lewycky wrote: