[LLVMdev] CFG as DOT: where do node addresses come from?

[Trevor Harmon]

Hi,

The -dot-cfg option of opt will write a diagram of an analyzed  
function's CFG to DOT format. If you then open the DOT file, you will  
see that the BasicBlocks are uniquely identified with hexadecimal  
addresses. For example, an edge from one block to another may look like:

	Node0x10026b0:s0 -> Node0x1004c20;

I've been trying to figure out where these hexadecimal addresses come  
from. I've been up and down the code but remain at a loss. I can see  
where GraphWriter.h is actually writing the strings to the DOT file,  
and I can see that some of the DOT data is coming from DOTGraphTraits  
in CFGPrinter.h. But the hexadecimal addresses are a mystery. I  
thought perhaps a BasicBlock method, such as getName, might be  
producing the addresses, but no.

Can anyone shed some light on this for me? Thanks,

Trevor