Call PassManager's debug hook even after a failing pass #4626
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vlstill
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| if (node) { | ||
| node->apply(toP4); | ||
| } else { | ||
| *stream << "No P4 program returned by the pass" << std::endl; |
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So this only happens when there is an error right? I would clarify this in the message.
ir/pass_manager.cpp
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| if (stop_on_error && ::errorCount() > initial_error_count) break; | ||
| if ((program = after) == nullptr) break; | ||
| if (stop_on_error && ::errorCount() > initial_error_count) early_exit_flag = true; | ||
| if ((program = after) == nullptr) early_exit_flag = true; |
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What does it mean when (program = after) == nullptr? Unclear to me.
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I think this is C/C++'s fun "you can embed assignment statements inside of expressions" thing, semantically equivalent to doing:
program = after;
if (program == nullptr) early_exit_flag = true;
Or maybe I don't understand your question.
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Oh yes, it was more meant as a clarification question under which circumstances the after is nullptr.
But that expression should also be simplified while we are at it.
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At least the Transform's code suggests it is possible to return nullptr in the pre/postorder and if you do that for root the entire apply would yield nullptr. This would be quite weird I guess, but it is allowed.
I've pushed a commit that eliminates the after variable altogether.
One effect I can see is that the compiler will attempt to dump P4 also form the pass that triggered an error. That would of course happen only if dumping is enabled, so in develompment. The rest will depend on the debug hooks used by downstream projects, which is hard to know... If this turns out to be problematic, the hook can always check |
breaking change: Debug hooks in
PassManagercan now be called with the IR::Node beingnullptr. This indicates that the last executed pass failed and did not return any value.This allows running a debug hook also after a failing pass too. This can be useful e.g. to check diagnostic counts for the pass in the debug hook.