Can't yield item from ValueRef iterator.

Store instruction in llvm ir. i would like to get second operand. “<pointer>” by using next function. but how many use next. it always return first operand. python for clause works. but next function doesn’t work.

I did something wrong? my test code like this.

def applyConstraint(instruction: llvm.ValueRef):
	if instruction.opcode == 'store':
		print(instruction.operands.next())
		print(instruction.operands.next())
		for i in instruction.operands:
			print(i)

[dbwodlf3]

I appreciate your answer!

[gmarkall]

Thanks for the details - I can now see the issue. When you call instruction.operands.next(), instruction.operands gives you a new _OperandsIterator - so when you call next() on it, you get the first operand. When you then do instruction.operands.next() on the following line, instruction.operands gives a new _OperandsIterator again, so calling next() on it gives you the first operand again.

Your code:

for function in module.functions:
    for block in function.blocks
        for instruction in block.instructions:
            # HERE operands IS NOT LIST.
            # HERE operands is ITERATOR TYPE.
            # _OperandsIterator TYPE.       
            for operand in instruction.operands:
                print(operand)

written using next() instead could look like this to accomplish what you were originally trying to do:

for function in module.functions:
    for block in function.blocks:
        for instruction in block.instructions:
            if instruction.opcode == 'store':
                ops = instruction.operands # ops holds the _OperandsIterator
                print(ops.next()) 
                print(ops.next())

With your simple2.ll file, this gives me the output:

i32 %foo
  %alloca_ins1 = alloca i32
i8 1
  %alloca_ins1 = alloca i8
i16 2
  %alloca_ins2 = alloca i16
i32 3
  %alloca_ins3 = alloca i32
i64 4
  %alloca_ins4 = alloca i64