Analyze across the call graph #8
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- Need to implement invalidation - Need to work out a better way to trigger the upper-level pass from the lower-level one / put it in the pipeline
For some reason, this is getting bogged down in the _loop analysis_ part of the per-function evaluation...eh? Weird.
The same pass (`FunctionBoundedTermination`) completes as expected when invoked from a function-level transform pass (`print<function-bounded-termination>`), but not when invoked from a module-level transform pass `print<bounded-termination>` Is this something weird with the proxy?
Several (all?) testdata files were failing when the `FunctionTerminationPass` was run via proxy (from the module-level pass), instead of being run at the function level. Unfortunately, "run from the module" is the only way we think we can handle the call-graph level analysis. The symptom was LLVM stalling out -- looping forever? -- when we asked for `ScalarEvolutionAnalysis`. I opened up LLDB and stepped through, and... it was fine! Looking at `simple.c`, the pass produced results for `get_value` and `main` just fine. ...but our functions are not the only functions listed in a module! For instance, `simple.c` invokes `malloc`; as a result, `malloc` gets a `declare`d in our module, without a function body. And *that's* where the analysis was stalling out -- our pass was running on `F.getName() == "malloc"`! Apparently, function-level passes are only run across functions `define`d in the module -- but the listing of module contents includes functions `define`d or `declare`d. I haven't really checked this, but it is consistent with what we've seen, and would explain the difference between running in function/module modes. My fix (this commit) is to return `Unknown` if the function does not have a body, i.e. has no basic blocks. This gets us back to a passing -- though incorrect -- state.
This doesn't propagate it back via the worklist, but it does tell us about recursive loops.
cceckman
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...I think this does what it's supposed to.